Research team

Peripheral Neuropathies Group

Expertise

The Peripheral Neuropathy Group has expertise in mapping and identifying genes, and in studying the effect of mutations on the normal functioning of genes via neuronal and non-neuronal cell lines. This information is compared to clinical, neurophysiological and neuropathological data which are essential for genotype/phenotype correlations. The construction of transgenic models is complementary to the clinical and cellular research, and enables to unravel the pathomechanisms for sensory and/or motor neuropathies. We have further expertise in identifying genes through differential suppressive subtraction hybridisation in primary motor and sensory neurons, construction of cDNA libraries, identification of genomic and protein structures, and gene expression in neuronal and non-neuronal cells, including Schwann cells. We make use of transient and stable transformations, but also of the Crispr/Cas9 genome editing technology. In recent years we gained knowledge with microscopy technologies and the phenotyping of mouse and Drosophila models for peripheral neuropathies.

Structural basis for disease-causing mutations in the molecular chaperone HSP27. 01/04/2021 - 31/03/2022

Abstract

Small heat-shock proteins (sHSPs) are ubiquitously expressed molecular chaperones that play vital roles in the maintenance of protein homeostasis. Our structural understanding of these chaperones, however, remains limited because sHSPs assemble into large, heterogeneous oligomers that have proven refractory to traditional structural biology approaches. So far, most work has relied on heavily engineered variants to isolate a single oligomeric form, which may no longer represent a biologically meaningful state. Our recent work showed that this roadblock can be circumvented by studying disease-causing variants that interfere with central properties of these chaperones. Here, we propose to study the structural consequences of HSP27 in which mutations cause motor neuropathies.

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IMARK. Network for image-based biomarker discovery and evaluation 01/01/2021 - 31/12/2026

Abstract

IMARK capitalizes on the deeply rooted expertise in biomedical imaging at the University of Antwerp to push the boundaries of precision medicine. By resolving molecular and structural patterns in space and time, IMARK aims at expediting biomarker discovery and development. To this end, it unites research groups with complementary knowledge and tools that cover all aspects of imaging-centred fundamental research, preclinical validation and clinical evaluation. IMARK harbours high-end infrastructure for electron and light microscopy, mass spectrometry imaging, magnetic resonance imaging, computed tomography, positron emission tomography and single-photon emission computed tomography. Moreover, IMARK members actively develop correlative approaches that involve multiple imaging modalities to enrich information content, and conceive dedicated image analysis pipelines to obtain robust, quantitative readouts. This unique blend of technologies places IMARK in an excellent position as preferential partner for public-private collaborations and offers strategic advantage for expanding the flourishing IP portfolio. The major application fields of the consortium are neuroscience and oncology. With partners from the Antwerp University Hospital and University Psychiatric Centre Duffel, there is direct access to patient data/samples and potential for translational studies.

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Validation of autophagy induction as a therapeutic strategy: from drug discovery and preclinical evaluation to safety investigation and biomarker research. 01/01/2021 - 31/12/2024

Abstract

Autophagy is a ubiquitous process that removes unnecessary or dysfunctional cellular components from the cytoplasm. Defective autophagy is currently emerging as a hallmark of many diseases. In this framework, there is strong interest in pharmacological agents that stimulate autophagy (so-called 'autophagy inducers'), as a potential treatment for these diseases. The unequivocal validation of autophagy induction as a therapeutic strategy, however, is far from established. Many obstacles persist, including the lack of druglike, selective autophagy inducers and readily translatable preclinical results that are obtained with such compounds. In addition, the availability of reliable biomarkers for autophagy and additional fundamental safety data for the approach, would strongly contribute to its validation. This proposal addresses existing limitations in the state-of-the art in the domain. We have recently carried out a phenotypic High-Throughput Screen (HTS) on a curated compound library. Members in this library were preselected from different providers based on in silico druglikeness scores. One compound family that was identified in the screen and maximally validated prior to this application, will be further optimized chemically for autophagy induction potency and biopharmaceutical properties. The biopharmaceutical profile of the best new representative will be thoroughly characterized in vivo, both involving PET-based pharmacokinetics and phenotypic pharmacodynamics. The compound will subsequently be investigated in two mouse models of diseases characterized by defective autophagy: atherosclerosis and Charcot-Marie-Tooth periferal neuropathy. In addition, we propose to investigate whether autophagy induction is intrinsically sufficiently safe as a therapeutic strategy. Existing hypotheses that autophagy induction could accelerate tumorigenesis and/or tumor growth will be investigated in vivo. In the same framework, metabolomics will be relied on to monitor eventual cellular stress fingerprints that result from chronic or long-term autophagy stimulation. Finally, metabolomics will also be relied on to identify cellular biomarkers of autophagy induction. The latter will be validated in plasma samples of animals that were systemically treated with autophagy inducers. Combined, we expect the knowledge and tools that are generated by this proposal to have strong impact on the field of autophagy research and ongoing endeavors to validate autophagy induction as a therapeutic strategy.

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Treatment of autophagy deficits in Charcot-Marie-Tooth disease caused by mutations in the small heat shock proteins HSPB1 and HSPB8. 01/01/2021 - 31/12/2024

Abstract

Autophagy is a normal physiological process that removes unnecessary or dysfunctional cellular components from the cytoplasm. Defective autophagy is currently emerging as a hallmark feature of many diseases, including Charcot-Marie-Tooth (CMT) neuropathy. In this framework, basic research and drug development have a strong need for reliable, drug-like autophagy inducers. We carried out a phenotypic high-throughput screen on compounds that were preselected based on drug likeness parameters. In total, 3 distinct chemical families were identified that previously have not been associated with autophagy induction. After thorough validation, potency and gross mode-of-action studies, the most promising chemical family was prioritized. Structure-activity relationships will be constructed for this chemical family. In addition, chemical optimization will be pursued to obtain novel representatives with further improved potency and a maximally favorable physicochemical profile. Efforts will be done for target finding. All novel compounds will be thoroughly investigated in a cell model for CMT neuropathy associated with mutations in the small heat shock proteins HSPB1 and HSPB8. To fully characterize this translational potential, in vivo evaluation in an established mouse model will be carried out for one maximally optimized compound.

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Neuro-spectrinopathies: approaching the phenotypical heterogeneity issue 01/11/2020 - 31/10/2022

Abstract

Next Generation Sequencing (NGS) technologies have resulted in the accumulation of a large amount of genetic causes for Mendelian diseases, with often no clear-cut link or evident cellular function correlating to the phenotype available. Conversely, a multitude of patients with Rare Diseases, of which many suffer from neuropathies, are lacking a genetic etiology. SPTAN1 (?-II-spectrin) provides an excellent example of this, with a notably high phenotypical heterogeneity but surprisingly little known about its molecular biology and cellular functions. Previously only associated with epilepsy and intellectual disability, we recently published novel mutations in SPTAN1 associated with Hereditary Motor Neuropathy (HMN). Furthermore, our own unpublished data show patients with ataxia and Hereditary Spastic Paraplegia (HSP), widening the phenotypical spectrum even further. I set out to uncover the molecular causes of the phenotypical heterogeneity present in SPTAN1, starting with the curation of an extensive database of SPTAN1 mutations and their associated phenotypes. Leveraging the information contained in this database through the use of machine learning techniques, I will perform experiments in carefully chosen patient-derived induced Pluripotent Stem Cells (iPSCs) that will allow the uncovering of differential effects between variants in SPTAN1 and their associated phenotypes, yield novel candidate genes for such disorders and teach us about the patho-biology of spectrins.

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Characterization of a novel chaperone-system in the mitochondrial intermembrane space. 01/10/2020 - 30/09/2023

Abstract

Mitochondria are composed of ~1100 proteins of which more than 99% are imported. Proteins are imported in an unfolded manner through pores in the outer and inner mitochondrial membrane (TOMs and TIMMs, respectively). Once imported, the unfolded peptides must be refolded into their native conformation. This requires a dedicated protein quality control system in each of the different mitochondrial compartments. To this end, the mitochondrial matrix contains a specific set of molecular chaperones (like mtHSP60 and mtHSP70). However, classical chaperones like Hsp70 and Hsp90 have not been identified in the mitochondrial intermembrane space (IMS). So how proteins are folded in the IMS remains incompletely understood. The mitochondrial IMS developed from the bacterial periplasm and, since the periplasm is devoid of ATP, the periplasm was shown to contain a number of ATP-independent chaperones such as Skp, Spy and HdeA. This suggests that mammalians might possess equivalent chaperones in the IMS. Indeed, we have identified a new class of chaperones that are also ATP-independent and which reside in the mitochondrial IMS. In this proposal we aim to elucidate how this new chaperone system contributes to the mitochondrial proteostasis.

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Multi-well microelectrode array (MEA): a bridge to highthroughput electrophysiology. 01/05/2020 - 30/04/2024

Abstract

This project aims to upgrade the current electrophysiology technologies at UAntwerpen by acquiring a state-of-the-art MicroElectrode Array platform (MEA). To study the electrophysiological properties of excitable cells, currently patch-clamping is the gold standard. However, this is an extremely labour-intensive and invasive technique, limited to short-term measurements of individual cells at single time points. On the other hand, MEAs enable high-throughput non-invasive longitudinal real‐time measurements of functional cellular networks, without disrupting important cell-cell contacts, and thus provide a more physiologically relevant model. The multi-well format allows repeated recordings from cell cultures grown under various experimental conditions, including the opportunity to rapidly screen large drug libraries. Based on these advantages, multi-well MEAs are the most suitable instrument for functionally elucidating the pathomechanisms of neurological/cardiac disorders by performing (1) cardiac activity assays: measurement of field and action potentials from (iPSC-)cardiomyocytes to investigate wave-form, propagation and irregular beating; (2) neural activity assay based on three key measures: frequency of action potential firing, synchrony as measure for synaptic strength and oscillation as hallmark for neuronal organization in time; (3) (iPSC-)vascular smooth muscle contractility assay based on impedance alterations.

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Interactive and intelligent cellomics platform. 01/05/2020 - 30/04/2024

Abstract

Crucial insights in cell and developmental biology have been gained by virtue of live cell imaging technology. Along with a growing complexity of cellular models and the finesse with which they can be genetically engineered, comes a demand for more advanced microscopy. In brief, modern comprehensive cell systems research (cellomics) requires light-efficient, intelligent and interactive imaging modalities. To address this shared need, our consortium has identified a state-of-the art platform that allows ultrafast, yet minimally invasive imaging of small to medium-sized biological samples (from single cells to organoids) at high resolution, so as to capture dynamic events that range in timescale from voltage fluctuations to successive cell divisions. To only focus on those events that are truly of interest, and thereby boost throughput, the system is equipped with online image recognition capabilities. Finally, to allow targeted perturbations such as local damage induction or optogenetic switching, small regions can be selectively illuminated in the field of view. With this level of control, it will become possible to interrogate (sub-)cellular processes with unprecedented detail. The platform readily finds applications in diverse frontline research fields including neuroscience, cardiovascular research and infectious diseases, rendering it an indispensable asset for the applicants, the microscopy core facility and the University of Antwerp.

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Multidimensional analysis of the nervous system in health and disease (µNeuro). 01/01/2020 - 31/12/2025

Abstract

Neuropathological research is an interdisciplinary field, in which imaging and image-guided interventions have become indispensable. However, the rapid proliferation of ever-more inquisitive technologies and the different scales at which they operate have created a bottleneck at the level of integration, a) of the diverse image data sets, and b) of multimodal image information with omics-based and clinical repositories. To meet a growing demand for holistic interpretation of multi-scale (molecule, cell, organ(oid), organism) and multi-layered (imaging, omics, chemo-physical) information on (dys)function of the central and peripheral nervous system, we have conceived μNEURO, a consortium comprising eight established teams with complementary expertise in neurology, biomedical and microscopic imaging, electrophysiology, functional genomics and advanced data analysis. The goal of μNEURO is to expedite neuropathological research and identify pathogenic mechanisms in neurodevelopmental and -degenerative disorders (e.g., Alzheimer's Disease, epilepsy, Charcot-Marie-Tooth disease) on a cell-to-organism wide scale. Processing large spatiotemporally resolved image data sets and cross-correlating multimodal images with targeted perturbations takes center stage. Furthermore, inclusion of (pre)clinical teams will accelerate translation to a clinical setting and allow scrutinizing clinical cases with animal and cellular models. As knowledge-hub for neuro-oriented image-omics, μNEURO will foster advances for the University and community including i) novel insights in molecular pathways of nervous system disorders; ii) novel tools and models that facilitate comprehensive experimentation and integrative analysis; iii) improved translational pipeline for discovery and validation of novel biomarkers and therapeutic compounds; iv) improved visibility, collaboration and international weight fueling competitive advantage for large multi-partner research projects.

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Genome and transcriptome engineering with CRISPR/Cas as a precision medicine for Charcot-Marie-Tooth type 2L. 01/01/2020 - 31/12/2023

Abstract

Patients with Charcot-Marie-Tooth disease (CMT) have a hereditary motor and sensory neuropathy causing a length-dependent degeneration of their peripheral nerves. Most patients have a duplication on chromosome 17 resulting in a higher expression of the peripheral myelin protein 22 (PMP22). Finding ways to reduce PMP22 expression has led to the development of a treatment for this group of patients. However, a significant number of CMT patients are incurable due to rare mutations in more than 90 different genes, complicating the development of effective treatment strategies. In this TOP project we aim to make use of the cutting-edge CRISPR/Cas technology to selectively eliminate or even correct a mutant transcript. As proof-of-concept we will focus on a dominant missense mutation occurring in the small heat shock protein HSPB8 causing an axonal subtype of CMT neuropathy. Complete deletion of this gene is only associated with mild (subclinical) symptoms. This therefore provides a therapeutic window where specific elimination of the mutant allele may lead to amelioration of the phenotype. We will thus first establish a proof-of-principle by introducing CRISPR/Cas9 with adeno-associated virus (AAV) to selectively inactivate the mutant allele in vivo. Then, we will assess if we can obtain the same specificity with CRISPR/Cas13b which selectively degrades RNA molecules and may thus reduce the risk of introducing permanent off-target effects. Finally, we will assess the possibility to correct mutant transcripts back to wild type with disabled Cas13b coupled base editors. These in vivo studies in the Hspb8 knock-in mouse model will be complemented by motor neurons differentiated from HSPB8 patient derived induced pluripotent stem cells (iPSCs). With these cutting-edge genome and transcriptome engineering approaches we aim to explore the potential of this approach for patients with peripheral neuropathies who cannot be treated with current medicines.

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An integrated multi-purpose basic infrastructure for dynamic and sensitive metabolic profiling of cells and embryos. 01/01/2020 - 31/12/2021

Abstract

Mitochondria are the driving force behind virtually all vital cellular processes, including cellular proliferation, differentiation, cell death and epigenetic regulation. Consequently, their dysfunction is intricately connected to altered metabolic states and disease progression. We aim at acquiring a Seahorse XFp Analyzer, which can directly measure mitochondrial respiration and glycolysis through Oxygen Consumption Rate (OCR) and Extracellular Acidification Rate (ECAR) in different biological samples. Determination of cellular metabolic phenotype and mitochondrial activity is crucial for precise characterization of the research models and the pathophysiological alterations studied in various research disciplines across the University of Antwerp; including reproductive biology and toxicology, cell biology, neurodegenerative disease, cardiovascular function, cancer, obesity, diabetes, metabolic disorders, immunology, virology and toxicology, amongst others. This is also a key for drug screening and development of new treatment strategies. Seahorse XF analyzers offer the most sensitive and accurate technology with the highest throughput compared to other alternatives. It has contributed to ground-breaking discoveries demonstrated in an increasing number of publications in different research fields about the critical role of metabolism in a wide variety of diseases. It has been successfully applied on various types of cells and tissues including mammalian gametes, primary cells, adherent and suspension cell lines, cells differentiated from induced pluripotent stem cells, isolated mitochondria, 3D cultures, Zebrafish and mammalian embryos, roundworms, fruit flies and yeast. Adding to the broad applicability of the platform, the XF technology employs a label-free, non-invasive methodology allowing samples to be used post-measurement for other investigations. The Seahorse XFp Analyzer will directly contribute to several ongoing and future research within laboratories belonging to different departments and faculties at UA. Furthermore, this new platform will not only facilitate our on-site accessibility, but will also increase our national and international competitiveness. It will further support multidisciplinary networking and collaboration and shall further increase our scientific research excellence.

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Targeting and delineating autophagic deficits caused by small heat shock protein mutations in CMT. 01/11/2019 - 30/10/2021

Abstract

Small heat shock proteins (sHSP) prevent the formation and accumulation of toxic protein aggregates in cells and help to clear these aggregates through autophagy. Mutations in the small heat shock protein HSPB1 disturb the formation of SQSTM1/P62 bodies, an important structure in the process of the autophagic flux. Also depletion of another family member, HSPB8, impairs the formation of P62 bodies. Mutations in HSPB1 and HSPB8 cause Charcot-Marie- Tooth disease or distal hereditary motor neuropathy, and both inherited peripheral neuropathies (IPN) are currently untreatable. We aim to identify FDA/EMA-approved molecules that are able to reverse the autophagic deficits caused by mutant HSPB1 and HSPB8. We will validate the effect of the selected drugs in motor neurons differentiated from patient-derived induced pluripotent stem cells (iPSC) with the aim to improve the neurodegenerative phenotype. In parallel with the drug screening, we will characterize the role of sHSPs in autophagosome formation, thereby providing insights in the molecular mechanism of this pathway. In summary, this project aims to target autophagy, the first shared pathomechanism between these two genes, and contributes to our understanding of the underlying molecular deficits.

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Targeting the immunodeficiency and neurodegeneration in a hereditary sensory neuropathy (HSAN type I) associated with dysfunction of the serine palmitoyltransferase. 01/10/2019 - 30/09/2023

Abstract

Since the discovery of disease-causing mutations in genes coding for the serine palmitoyltransferase (SPT) subunits SPTLC1 and SPTLC2, much progress has been made in understanding the underlying pathophysiology of hereditary sensory and autonomic neuropathy type I (HSAN-I). Dominant mutations in SPTLC1 and SPTLC2 influence the substrate specificity of the SPT enzyme leading to the formation of toxic deoxysphingolipids. Indeed, the mutant enzyme prefers to metabolise L-alanine or L-glycine instead of its natural substrate L-serine. The formation of neurotoxic deoxysphingolipids induce axonal degeneration in vitro and in vivo. Providing an excess of L-serine, and thereby reducing the relative abundance of L-alanine/L-glycine, was shown to reduce the formation of toxic deoxy-sphingolipids. Encouragingly, these findings were successfully translated from animal models to HSAN-I patients as demonstrated by a recent clinical trial on high-dose L-serine supplementation. However, two downsides of the L-serine supplementation therapy remain unsolved. On one hand, patients need to take very high doses of L-serine on a daily basis in order to maintain the suppressing effect. Secondly, while the treatment is effective in countering the neurodegeneration, it does not rescue the HSAN-I-associated immunodeficiency. In fact, patients on L-serine treatment even show a trend towards more immunological complications. We have preliminary results demonstrating that sphinganine supplementation was able to correct the CD8+ T cell deficiency in HSAN-I patients. This may therefore form a potent, yet simple, therapy which can rescue the T cell-intrinsic defects associated with HSAN-I. Whether sphinganine also provides beneficial effects for the peripheral nervous system remains to be tested. This PhD project therefore aims to investigate if additional supplementation with sphinganine could be beneficial to HSAN-I patients. To this end, we will develop human induced pluripotent stem cells (hiPSC) from HSAN-I patients with a SPTLC1 and SPTLC2 mutation. From the iPSC lines we will generate sensory neurons through optimization of an established protocol. These sensory neuron cultures will be supplemented with sphinganine and/or L-serine to assess their potency on rescuing the neurodegenerative phenotype. In addition, a transcriptomic analysis will be performed on CD8+ T cells treated with either sphinganine or L-serine to profile the underlying molecular differences related to T cell intrinsic defects and potentially identify other therapeutic options for ulcero-mutilating neuropathies.

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A preclinical study to treat neuromuscular disease caused by HSPB8 mutations (MDA577497). 01/08/2018 - 31/07/2021

Abstract

The small heat shock protein B8 (HSPB8) belongs to the 'stress protein family' and is expressed in various tissues and cells. HSPB8 acts as a molecular chaperone by clearing protein aggregates and reducing their toxic accumulation. This protective function has been studied in the context of cancer and neurodegenerative disease. We were the first to report disease causing mutations in the HSPB8 gene in patients with distal hereditary motor neuropathy, a variant of Charcot-Marie-Tooth neuropathy. Patients have a progressive degeneration of their peripheral nerves resulting in muscle weakness and atrophy. We generated a mouse model mimicking the human distal motor neuropathy by introducing a known disease causing mutation in the HSPB8 gene (a knock-in mouse). In addition we also made a model in which we deleted HSPB8 (a knock-out mouse) and these animals develop a mild myopathy. This project aims to identify therapeutic compounds that can rescue or delay the neurodegeneration observed in the knock-in model, or that can result in a milder phenotype as seen in the knock-out animals. The identified small molecule compound acting on the expression of HSPB8 could be beneficial to treat patients affected with distal hereditary motor neuropathy, but also patients with distal myopathies and related neuromuscular disorders.

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Solving the unsolved Rare Diseases (Solve-Rd). 01/01/2018 - 31/12/2022

Abstract

The main ambitions of the Solve-RD proposal are (i) to solve large numbers of RD, for which a molecular cause is not known yet, by sophisticated combined Omics approaches, and (ii) to improve diagnostics of RD patients through a "genetic knowledge web". Solve-RD will pursue a clear visionary and integrated "beyond the exome" approach. The entire Solve-RD proposal has been motivated, designed and put together by a core group of four ERNs, but also reaches out to all 24 ERNs. To tackle diseases which are unsolved by applying cutting edge strategies, Solve-RD has thus formed a consortium that comprises (i) leading clinicians, geneticists and translational researchers of these ERNs, (ii) RD research and diagnostic infrastructures, (iii) patient organisations, as well as (iv) leading experts in the field of -omics technologies, bioinformatics and knowledge management. Solve-RD will deliver 7 main implementation steps: (i) Collect Phenotypes, (ii) New phenotype patterns, (iii) Re-analyse exomes / genomes, (iv) Novel molecular strategies, (v) Functional analysis, (iv) Clinical utility and (vii) Towards therapy. For analysis Solve-RD will apply data driven and expert driven approaches. We anticipate to increase diagnostic yield from 19.000 unsolved exomes/genomes by about 3-5%. Cohort specific innovative -omis strategies will be pursued, also addressing cost-effective issues. Analysis of more than 800 patients with highly peculiar (ultra-rare) phenotypes will highly increase the chance to find novel disease genes and novel disease mechanisms. We anticipate to solve more than 2.000 cases. Finding further matching patients will be secured by newly developed matchmaking approaches and by screening using MIPs technology in the more than 20.000 unclassified patients of the ERNs. For the first time in Europe we will also implement a novel brokerage structure connecting clinicians, gene discoverer and basic researcher to quickly verify novel genes and disease mechanisms.

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A preclinical study to treat neuromuscular disease caused by mutations in the small heat check protein HSPB8. 01/01/2018 - 31/12/2021

Abstract

Patients with autosomal dominant distal hereditary motor neuropathy (dHMN) develop progressive motor impairments, weakness and wasting of lower limb muscles. We identified mutations in the small heat shock protein HSPB8 as one of the underlying genetic causes for this disease. More recently, distal myopathy was also found to be associated with mutations in HSPB8. So far, no treatment is available to delay or cure patients with mutations in HSPB8. Our research group generated a mouse model mimicking the symptoms observed in affected individuals by introducing a known disease-causing mutation (knock-in: KI). Additionally, we also generated a mouse model in which HSPB8 was deleted (knock-out: KO). Strikingly, the latter does not show any sign of neuronal damage or severe myopathy. We therefore hypothesise that reducing the levels of HSPB8 might help to alleviate the symptoms associated with dHMN. This project aims to identify therapeutic compounds that by reducing HSPB8 levels, can rescue or delay the neurodegeneration observed in the KI model. It could therefore deliver the first small molecule treatment for neuropathies and myopathies caused by mutations in HSPB8. Furthermore, this strategy will also open therapeutic possibilities for other neuromuscular and neurodegenerative diseases where HSPB8 plays a role in the pathology.

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Pharmacological modulation of autophagy as treatment for inherited neuropathies. 15/02/2020 - 31/12/2020

Abstract

Autophagy contributes to cellular homeostasis by promoting the bulk degradation of harmful misfolded proteins, aggregates and non-functional organelles from the cytoplasm. As molecular chaperones, small heat shock proteins (sHSP) operate in this pathway by assisting the formation of autophagy-competent vesicles, the autophagosomes. Mutations in the small heat shock protein HSPB1 disturb the formation of P62 bodies, the early seed necessary in the autophagic flux. Moreover, depletion of another family member, HSPB8, impairs the formation of P62 bodies. Mutations in HSPB1 and HSPB8 cause Charcot-Marie-Tooth disease or distal hereditary motor neuropathy, and both inherited peripheral neuropathies are currently untreatable. We aim to identify FDA/EMA-approved molecules that are able to reverse the autophagic deficits caused by mutant HSPB1 and HSPB8. We will validate the ability of the selected drugs to rescue the neurodegenerative phenotype in motor neurons differentiated from patient-derived induced pluripotent stem cells (iPSC). We will provide new insights into the molecular pathology underlying mutations in sHSP and how the candidate drug pharmacologically modulates autophagy. The project as a whole aims to target autophagy, the first shared pathomechanism caused by different mutations in sHSP, occurring in CMT neuropathies.

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Support maintenance scientific equipment (Peripheral Neuropathies). 01/01/2020 - 31/12/2020

Abstract

Maintenance contract of an Axiovert 200 fluorescence microscope with incubation chamber to be used in the research related to the Peripheral Neuropathy research group. This equipment was purchased on a previous FWO research grant.

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Targeting and delineating autophagic deficits caused by small heat shock protein mutations in CMT. 01/01/2019 - 31/10/2019

Abstract

Small heat shock proteins (sHSP) prevent the formation and accumulation of toxic protein aggregates in cells and help to clear these aggregates through autophagy. Mutations in the small heat shock protein HSPB1 disturb the formation of SQSTM1/P62 bodies, an important structure in the process of the autophagic flux. Also depletion of another family member, HSPB8, impairs the formation of P62 bodies. Mutations in HSPB1 and HSPB8 cause Charcot-Marie-Tooth disease or distal hereditary motor neuropathy, and both inherited peripheral neuropathies are currently untreatable. We aim to identify FDA/EMA-approved molecules that are able to reverse the autophagic deficits caused by mutant HSPB1 and HSPB8. We will validate the effect of the selected drugs in motor neurons differentiated from patient-derived induced pluripotent stem cells (iPSC) with the aim to improve the neurodegenerative phenotype. In parallel with the drug screening, we will characterize the role of sHSP in autophagosome formation, thereby providing insights in the mechanism of action of new drugs. In summary, this project aims to target autophagy, the first shared pathomechanism between these two genes, and it will contribute to our understanding of the underlying molecular deficits.

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A preclinical study to treat neuromuscular diseases caused by mutations in the small heat shock protein HSPB8 06/03/2018 - 05/03/2019

Abstract

HSPB8 belongs to the "stress protein family". Patients with HSPB8 mutations have a progressive degeneration of peripheral nerves. More recently mutations in HSPB8 were reported in patients with myofibrillar myopathy. We generated a mouse model mimicking the human distal motor neuropathy by introducing a mutation in the HSPB8 gene (knock-in mouse). In addition we made a model in which we deleted HSPB8 (knock-out mouse) and these animals develop a mild myopathy. We aim to find drugs that can rescue or delay the neurodegeneration observed in the knock-in model, or that can result in a milder phenotype as seen in the knock-out animals. The compound acting on the expression of HSPB8 could be beneficial to treat patients affected with neuromuscular disorders.

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How does mitochondrial dysfunction contribute to the CMT2F pathogenesis caused by HSPB1 mutations. 01/01/2018 - 31/12/2018

Abstract

Mutations in the small heat shock protein B1 (HSPB1) cause an axonal variant of Charcot-Marie-Tooth neuropathy (CMT2F). It remains challenging to understand why mutations in an ubiquitously expressed chaperone only affect the motor and sensory nerves. Moreover, more than 80 genes can cause CMT and it is unknown how small heat shock proteins relate to those other CMT-subtypes. One interesting observation has been that the number of mitochondria is decreased in sensory neurons of post-symptomatic CMT2F mice. This project aims to decipher the mechanistic role of wild type and mutant HSPB1 in mitochondrial functioning.

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Unravelling the novel molecular pathways contributing to distal hereditary motor neuropathy caused by mutant HSPB8 with the aim to identify potential therapeutic targets. 01/01/2017 - 31/12/2017

Abstract

The development of induced pluripotent stem cells (iPSC) has brought together the genetic accuracy of a patient-derived model and the possibility of having the disease-specific cell type. This model promises to influence modern medicine and drug development particularly for neurological disorders by providing an unlimited access to patient-derived neurons. We will take advantage of the iPSC model along with a mouse model to identify and validate translationally relevant pathway(s) leading to axonal degeneration, and with the ambition to select and test promising therapeutic targets.

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Modular confocal microscopy platform with light sheet illumination. 01/05/2016 - 30/04/2020

Abstract

The application concerns an innovative microscopy platform for visualizing cells, tissue specimen and living small model organisms in three dimensions at unprecedented speed and with excellent resolution and contrast. As a unique feature, the platform is equipped with a light-sheet module, which is based on an orthogonal configuration of laser-generated, micrometer-thin plane illumination and sensitive one-shot detection. Seamless integration with confocal modalities enables imaging the same sample from the micro- to the mesoscale. The device has a broad application radius in the neurosciences domain inter alia for studying neurodegeneration and -regeneration (e.g. whole brain imaging, optogenetics); but it also has direct utility in various other fields such as cardiovascular research (e.g. plaque formation and stability), plant developmental research (e.g. protein localization during plant growth) and ecotoxicology (e.g. teratogenicity and developmental defects in zebrafish). Furthermore, its modular construction will enable adaptation and targeted expansion for future imaging needs.

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Identification of the common signature pathways of axonal degeneration in Charcot-Marie-Tooth neuropathies as a framework to develop therapeutic strategies. 01/01/2016 - 31/12/2019

Abstract

Recent research has unraveled some gene-specific disease mechanisms that lead to Charcot-Marie-Tooth (CMT) neuropathies. However, this 'single-gene' approach may prove insufficient to build an efficient therapeutic strategy for a disease, genetically diverse, as CMT. We therefore propose to identify 'common signature pathways' (CSPs) linking different genes involved in the axonal variant of CMT. An "axonal signature" of CMT will be sketched by proteomic analysis of isogenic cell lines containing mutations in CMT genes created with the CRISPR/Cas9 technology. As a proof-of-concept we will evaluate the therapeutic potential of the identified pathways. We will assess the capacity of repurposed drugs on alleviating CMT symptoms using in vitro and in vivo models upon modulation of the CSP. This FWO project will open new and attractive avenues for drug development for CMT neuropathies.

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High throughput microscopy. 01/06/2015 - 31/12/2016

Abstract

In the framework of this project, a method will be established for automated and standardized microscopic evaluation of large numbers of biological samples. Protocols will be tailored for histological tissue preparations and for cell cultures. To this end, a combination of optics, robotics and bio-image informatics will be used.

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Small heat shock proteins in healthy conditions and in disease. 01/01/2015 - 31/12/2019

Abstract

This is a fundamental research project financed by the Research Foundation – Flanders (FWO). The project was subsidized after selection by the FWO-expert panel. Our objective is to generate a more complete understanding on the function of this family of proteins, with the specific goal of explaining how congenital mutations affect activity and lead to disease. The cooperation between the respective laboratories will permit the examination of these proteins at the basic molecular level using modern structural methods and biochemical analysis, with the aim to understand the properties of these proteins and then essentially provide the opportunity to translate these findings into in vivo studies.

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Role of HSPB1 mutations in the mRNA metabolism in Charcot-Marie-Tooth neuropathies. 01/10/2014 - 15/10/2016

Abstract

This project aims to use mouse models to study the ubiquitous, neuron, and Schwann cell specific effects of mutant sHSP. Besides the phenotyping of these mouse models, we will investigate the bioenergetics and antioxidant status in their neurons and the supporting myelinating Schwann cells. As both genes have very similar biological functions, this study will provide further insights into a possible common pathomechanism for peripheral neuropathies.

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Research team(s)

ER/mitochondrial crosstalk and homeostasis as a common pathomechanism for inherited peripheral neuropathies. 01/10/2014 - 30/09/2016

Abstract

The aim of this PhD project is to explore the role of two proteins, SPTLC2 and Mitofusin-2, in endoplasmatic reticulum (ER) / mitochondria homeostasis and crosstalk related to inherited peripheral neuropathies. We will make use of technologies such as: cellular models (cell lines and primary neurons), molecular cell biology, lipidomics, microscopic analysis of mitochondria associated membranes (MAMs) and calcium homeostasis.

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Study of the pathomechanisms of HSPB1 and HSPB8 mutations in iPSC derived motor neurons of Charcot-Marie-Tooth patients. 01/01/2014 - 31/12/2017

Abstract

To further progress towards understanding the disease mechanisms we aim to develop motor neuron cultures differentiated from patient-derived induced pluripotent stem cells (iPSC). This promising and novel functional approach in translational research will allow studying the complex disease mechanisms of small heat shock protein mutations. This project will ultimately contribute to the development of an efficient and relevant drug testing platform for motor neuropathies.

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Macroautophagy: a common pathomechanism of mutant small heat shock proteins causing peripheral neuropathies? 01/10/2013 - 30/09/2016

Abstract

The aim of my project is to dissect common disease mechanisms in inherited peripheral neuropathies caused by mutation in HSPB1 and HSPB8. I propose to study the role of autophagy using novel transgenic mouse models recently generated by the lab.

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VIB-Integrated European -omics research project for diagnosis and therapy in rare neuromuscular and neurodegenerative diseases (NEUROMICS). 01/10/2012 - 30/09/2017

Abstract

This project represents a formal research agreement between UA and on the other hand EU. UA provides EU research results mentioned in the title of the project under the conditions as stipulated in this contract. Neuromics (FP7 framework programme) studies 10 rare neurodegenerative and neuromuscular diseases with the aim to: 1. find novel disease-causing genes, 2. improve diagnostics, and 3. develop novel therapies for these disorders. More details can be found on: http://rd-neuromics.eu

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Role of HSPB1 mutations in the mRNA metabolism and redox balance in Charcot-Marie-Tooth neuropathies. 01/10/2012 - 30/09/2014

Abstract

This project aims to use mouse models to study the ubiquitous, neuron, and Schwann cell specific effects of mutant sHSP. Besides the phenotyping of these mouse models, we will investigate the bioenergetics and antioxidant status in their neurons and the supporting myelinating Schwann cells. As both genes have very similar biological functions, this study will provide further insights into a possible common pathomechanism for peripheral neuropathies.

Researcher(s)

Research team(s)

Identification of molecular players and drug targets for DICMTC neuropathy. 01/10/2012 - 30/09/2014

Abstract

Charcot-Marie-Tooth disease (CMT) is the most common inherited neuromuscular disorder, affecting 1/2500 individuals worldwide. The main symptoms are progressive distal muscle weakness and wasting, sensory loss, reduced tendon reflexes, and foot and hand deformities. More than 500 mutations in over 40 genes have been implicated with this type of pathology providing more accurate CMT diagnosis. However, no effective therapies are available to treat CMT patients. Dominant intermediate CMT type C (DI-CMTC) is a recently defined CMT entity, characterized by axonal degeneration and demyelination of peripheral neurons. We were the first to describe DI-CMTC and demonstrated that it is caused by specific mutations in the gene encoding for tyrosyltRNA syntethase (YARS). This application is focused on the identification of molecular players and potential drug targets for this particular subtype of CMT. We will perform a screen for genetic modifiers of neurodegenerative phenotypes present in our recently generated Drosophila DI-CMTC model. The targeted genes will be selected based on their predicted abilities to interact with drug-like compounds. In this way, we will be able to gain original knowledge on DI-CMTC pathomechanisms and to translate it into a rational and reliable drug discovery program for this and possibly other inherited and acquired neuropathies.

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Negative regulation of the innate immune response in the peripheral nerve. 01/01/2012 - 31/12/2013

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Identification of common molecular pathomechanisms of RAB7 and SPT mutations causing hereditary sensory neuropathies. 01/01/2011 - 31/12/2014

Abstract

The goal of this research project is to investigate the possible common pathomechanism of two severe neurodegenerative diseases of the peripheral nervous system (PNS), Charcot-Marie-Tooth type 2B and Hereditary Sensory Neuropathy type I, in vitro and in vivo.

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CLCI - High end infrastructure for confocal live cell imaging. 22/07/2010 - 28/04/2015

Abstract

This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

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The Biomark Microfluidics system for high throughput genotyping, expression profiling and CNV analysis. 22/07/2010 - 30/09/2013

Abstract

The microfluidic BioMark¿ Genetic Analysis Platform from Fluidigm (www.fluidigm.com) is a fully integrated system enabling high throughput analysis of gene expression, SNP genotyping and absolute quantification of nucleic-acid sequences utilizing Digital and/or Dynamic Array Integrated Fluidic Chip (IFC) technology. Besides increasing the genetic and genomic analysis capacity the system at the same time enables significant reduction in the use of precious DNA/RNA samples and significant reduction (up to 100-fold) of consumable cost due to the nanoliter based reaction volumes (i.e. cost per datapoint).

Researcher(s)

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    Molecular pathomechanisms of HSPB1 and HSPB8 mutations in motor neuropathies: study of protein-protein interactions and axonal transport in cellular and animal models. 01/01/2010 - 31/12/2013

    Abstract

    In recent years more than 30 disease-associated genes for inherited peripheral neuropathies have been identified and at least one third of these encode proteins with housekeeping functions, such as: stress response, RNA processing, translation synthesis, and apoptosis (Timmerman et al., 2006). The motor neurons seem to be particularly vulnerable to defects in these housekeeping proteins likely because their large axons have high metabolic requirements for maintenance, transport over long distances and precise connectivity (Van Den Bosch and Timmerman, 2006). In this 4-year project, we will determine how mutations in small HSPs (HSPB1 and HSPB8) contribute to cellular stress in motor neurons by the development and use of cellular and mouse models. By a proteomics approach, we will identify differentially interacting proteins for the mutant and wild type (wt) HSPB1 and HSPB8. These proteins will provide new insights into the pathomechanisms of motor neuropathies and deliver novel disease associated genes.

    Researcher(s)

    Research team(s)

    Negative regulation of the innate immune response in the peripheral nerve. 01/01/2010 - 31/12/2011

    Abstract

    This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

    Researcher(s)

    Research team(s)

    Molecular biological research of HSPB8 mutations in relation to hereditary neuron disorders. 01/01/2010 - 31/12/2011

    Abstract

    The distal hereditary motor neuropathies (HMN) are a heterogeneous group of disorders characterized by the selective degeneration of motor neurons of the peripheral nervous system. Two disease causing genes, HSPB8 and HSPB1, were identified in our group for distal HMN type II. These genes belong to the super family of the small heat shock proteins (sHSPs). In this project we try to find an answer to the question why mutations in HSPB8 selectively affect peripheral motor neurons. Through in vitro cellular studies we investigate the functional consequences of mutations in HSPB8. Furthermore we will generate a knock-in mouse model to analyse the pathomechanism directly.

    Researcher(s)

    Research team(s)

    Functional consequences of RAB7 mutations in the pathogenesis of an ulcero-mutilating neuropathy. 01/07/2009 - 31/03/2012

    Abstract

    This postdoctoral research project aims at unravelling the pathogenesis of two ulcero-mutilating neuropathies, Charcot-Marie-Tooth 2B and Hereditary Sensory Neuropathy type I. The neuropathies show strong phenotypical similarities, but are caused by mutations in 2 different genes, respectively RAB7 and SPTLC1. Using primary sensory neurons, isolated from rat embryos and virally transduced with wild-type or mutant constructs, I will study the effect of the mutations on e.g. the endosomal population, lipid raft formation and axonal transport. Moreover, I will make a Drosophila model of both disorders, which will allow me to investigate how the mutations affect the peripheral nervous system in vivo and will help me to try to correlate the pathomechanisms of these two neuropathies.

    Researcher(s)

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    The role of the innate immune system in neurodegeneration and neuroprotection. 01/01/2009 - 31/12/2010

    Abstract

    We will study the role the innate immune response in the context of peripheral neurodegeneration. More specifically, we study the balance between neuroprotective and neurodegenerative aspects of the immune response. It will allow us to determine whether a controlled immune response is needed for proper nerve regeneration in the peripheral nervous system. This knowledge will further contribute to our understanding of the role of the innate immune response in nerve protection and nerve repair, and as such this can be important in future therapies for neurodegenerative diseases.

    Researcher(s)

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    Molecular genetic analysis of genes responsible for inherited axonal peripheral neuropathies. 01/01/2009 - 31/12/2010

    Abstract

    In this project, we aim to elucidate the pathomechanisms involved in hereditary sensory neuropathies. Hereditary sensory neuropathy (HSN) is a rare variant of hereditary peripheral neuropathies, characterized by progressive sensory loss in the distal parts of the limbs. Therefore, a genotype-phenotype correlation analysis was performed in a vast HSN-cohort of the known HSN-genes (SPTLC1, RAB7, HSN2, NTRK1, NGFB and CCT5) to provide better counseling, to gain more insight in the underlying disease mechanisms and to select mutations for further functional research. The second aim of this project is to identify novel genes for HSN. This is performed by screening functional and positional candidate genes.

    Researcher(s)

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    Transmission Electron Microscope with cryo-ware. 19/12/2008 - 18/12/2013

    Abstract

    This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

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    Molecular genetics and functional study of HSPB8 mutations associated with hereditary motor neuropathy. 01/10/2008 - 30/09/2011

    Abstract

    In this proposal, I intend to obtain better insights into the precise mechanisms underlying mutant HSPB8 protein resulting in specific neuronal degeneration. Our hypothesis is that distal HMN might be as a result of cell death of peripheral neurons due to aggregation and abnormal interaction of mutant HSPB8 protein. Mutant protein could interfere with the cytoskeleton network and axonal transport pathways, and this could ultimately lead to perikaryal atrophy and axonal loss. Another mechanism might be the impairment of energy production along this specialized axon which might alter axoplasmic transport activities or led to synaptic dysfunction.

    Researcher(s)

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    Molecular Genetics and Biology of Intermediate Charcot-Marie-Tooth neuropathy. 01/10/2008 - 30/09/2010

    Abstract

    In this FWO apirant mandate we will search for novel mutations in YARS associated with dominant intermediate CMT (DI-CMT), which is essential to make genotype-phenotype correlations. The development of animal models where cellular/tissue dysfunction can be evaluated in an in vivo situation is of crucial importance. Developing such a model in the model organism D. melanogaster will allow us to test the hypothesis on how DI-CMTC is triggered and to screen for genetic and chemical modulators of DI-CMT disease.

    Researcher(s)

    Research team(s)

    The role of the innate immune system in neurodegeneration and neuroprotection. 01/10/2008 - 31/12/2008

    Abstract

    We will study the role the innate immune response in the context of peripheral neurodegeneration. More specifically, we study the balance between neuroprotective and neurodegenerative aspects of the immune response. It will allow us to determine whether a controlled immune response is needed for proper nerve regeneration in the peripheral nervous system. This knowledge will further contribute to our understanding of the role of the innate immune response in nerve protection and nerve repair, and as such this can be important in future therapies for neurodegenerative diseases.

    Researcher(s)

    Research team(s)

    Molecular biology of tyrosyl-tRNA synthetase (YARS) mutations associated with peripheral neuropathy. 01/01/2008 - 31/12/2011

    Abstract

    So far, there are no reports of a relationship between YARS' function and maintenance of the PNS in health and disease. It is enigmatic how mutations in an ubiquitously expressed gene of supposedly general function can lead to specific neurodegenerative defects observed in peripheral neuropathies. We will pursue four objectives: (i) Estimate the aminoacylation activity of YARS in vitro and in vivo, and correlate it with the clinical severity of DI-CMTC, (ii) Determine whether YARS acts as a signaling molecule in the PNS, (iii) Identify neuron-specific protein interactions to explain the cell type specific phenotype, and (iv) Generate a fly model for DI-CMTC to study and identify the disease pathomechanism.

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    Molecular genetics and biology of Charcot-Marie-Tooth Neuropathies. 01/01/2008 - 31/12/2010

    Abstract

    We aim to perform an extended molecular and functional genetic research of new genes involved in inherited peripheral neuropathies by which we will gain more insights into the pathological mechanisms. This will lead to more possibilities for genetic counselling to patients and genotype-phenotype correlations. This research is also relevant to screen specific gene mutations in functional assays. An increasing functional knowledge will lead to possible therapeutic tools. The knowledge of novel genetic components in these disorders is also needed to obtain more insights into the disease mechanisms of the peripheral nervous system.

    Researcher(s)

    Research team(s)

    Molecular biological research of HSPB8 mutations in relation to hereditary neuron disorders. 01/01/2008 - 31/12/2009

    Abstract

    The distal hereditary motor neuropathies (HMN) are a heterogeneous group of disorders characterized by the selective degeneration of motor neurons of the peripheral nervous system. Two disease causing genes, HSPB8 and HSPB1, were identified in our group for distal HMN type II. These genes belong to the super family of the small heat shock proteins (sHSPs). In this project we try to find an answer to the question why mutations in HSPB8 selectively affect peripheral motor neurons. Through in vitro cellular studies we investigate the functional consequences of mutations in HSPB8. Furthermore we will generate a knock-in mouse model to analyse the pathomechanism directly.

    Researcher(s)

    Research team(s)

    The impact of the innate immune system in peripheral neuropathies. 01/10/2007 - 28/02/2011

    Abstract

    A neurodegenerative respons in peripheral axons tends to trigger an innate immune response in Schwann cells. In this project we would like to explore the precise role of this response and how it contributes to nerve regeneration and remyelination on one hand or - in cases where it gets out of control - to neurodegeneration on the other hand. A better understanding of these processes will allow us to manipulate and use this inherent capacity of our body for nerve protection and nerve regeneration in future therapies.

    Researcher(s)

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    Molecular genetic, biological and neurological research of inherited peripheral neuropathies: an integrated project. 01/07/2007 - 30/06/2011

    Abstract

    Identification of disease associated mutations in genes is a first step towards understanding of fundamental biological and biochemical processes involved in inherited disorders of the peripheral nervous system. A major topic of this project is therefore further identification of additional loci and genes. Knowledge of structure and function of genes is of major importance for classification and determination of underlying molecular pathomechanisms. In this project we focus on the pathomechanism of distal motor neuropathies, sensory neuropathies and the intermediate type of Charcot-Marie-Tooth. In our research groups we recently identified 3 novel genes and have already initiated functional in vitro and in vivo studies.

    Researcher(s)

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    An integrated approach to the unraveling of the pathogenesis of CNS and PNS neurodegenerative disorders. 01/01/2007 - 31/12/2011

    Abstract

    This network project is designed to apply the unique information provided by sequencing of the human genome to further the understanding of and to develop treatments for neurodegenerative diseases. The association in the proposed network of research groups in clinical research, human genetics and genomics, cell biology, proteomics, bioinformatics, and model organisms (mice, zebrafish and Drosophila), will create an integrated network that should allow identification of novel disease genes, determination of their biological functions, establishing their role in pathophysiological processes and identification of novel avenues for early diagnosis, treatment and prevention. The network will focus its research activities on diseases of the central nervous system (CNS) such as Alzheimer disease, Parkinson disease, frontotemporal dementia and related diseases; and diseases of peripheral nervous system (PNS) such as peripheral motoneuronopathies, amyotrophic lateral sclerosis and related disorders.

    Researcher(s)

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    Molecular genetic analysis of genes responsible for inherited axonal peripheral neuropathies. 01/01/2007 - 31/12/2008

    Abstract

    In this project, we aim to elucidate the pathomechanisms involved in hereditary sensory neuropathies. Hereditary sensory neuropathy (HSN) is a rare variant of hereditary peripheral neuropathies, characterized by progressive sensory loss in the distal parts of the limbs. Therefore, a genotype-phenotype correlation analysis will be performed in a vast HSN-cohort to provide better counseling, to gain more insight in the underlying disease mechanisms and to select mutations for further functional research. The second aim of my project is to identify novel genes for HSN. This is performed by screening functional and positional candidate genes.

    Researcher(s)

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    VIB-Molecular genetics of hereditary sensory neuropathies. 01/01/2007 - 31/12/2007

    Abstract

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    VIB-Molecular genetics of peripheral neuropathies. 05/10/2006 - 31/12/2006

    Abstract

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    Molecular Genetics and Biology of Intermediate Charcot-Marie-Tooth neuropathy. 01/10/2006 - 30/09/2008

    Abstract

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    Research of RAB7 and HSP22/27 in relation to Charcot-Marie-Tooth neuropathy type 2B and distal hereditary motor neuropathy type II. 01/01/2006 - 31/12/2009

    Abstract

    In a different and on-going FWD research project (G.0411.05, 2005-2008) we aim to investigate the molecular and functional genetic aspects of genes involved in inherited peripheral neuropathies. This new FWD project application (2006-2009) aims to extend our functional research with the study of mouse models for CMT28 and distal HMN II. CMT2B and distal HMN II are two extreme phenotypes in which mainly sensory neurons are affected in CMT2B, while motor neurons are affected in distal HMN II. For both phenotypes we identified the disease causing mutations; RAB7 for CMT2B and HSP22 for distal HMN type II. We will also involve HSP27 since it is an interacting partner of HSP22, and mutations in HSP27 cause distal HMN and CMT2F. Mouse models are essential to study the pathological mechanisms, such as neurodegeneration, and allow the study of potential therapies for inherited peripheral neuropathies.

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    Molecular genetic study of distal hereditary motor neuropathies (distal HMN). 01/01/2006 - 31/12/2007

    Abstract

    Distal hereditary motor neuropathies (distal HMN) are pure motor disorders of the peripheral nervous system resulting in severe atrophy and wasting of distal limb muscles. Distal HMNs are clinically and genetically heterogeneous. So far 8 loci and 3 genes have been identified for autosomal dominant and recessive distal HMNs. Recently, we identified missense mutations in a novel gene in distal HMN-II families. Via mutation analysis of these genes in families and isolated patients with a distal HMN phenotype, we will determine the relative frequency of mutations in these genes. Importantly, mutations have so far only been reported in distal HMN patients. We will investigate if mutations in these genes are correlated with a specific phenotype or whether these genes are involved in a wider disease spectrum. We will also investigate if genetic variations have a modulating effect in the disease process of amyotrophic lateral sclerosis (ALS) by performing genetic association studies. Finally, we will perform genome wide scans in distal HMN families not linked to the known distal HMN loci.

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    VIB-Molecular genetics of dominant intermediate Charcot-Marie-Tooth Neuropathies (CI-CMT). 01/01/2006 - 31/12/2006

    Abstract

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    VIB-Molecular genetic and functional analysis of HSP22/HSP27 mutations in relation to motor neuropathies. 01/07/2005 - 30/06/2008

    Abstract

    Our project aims to perform a molecular genetic and functional study of two small heat shock proteins (HSP22, HSP27), whose mutations we showed to be associated to distal hereditary motor neuropathies (distal HMN).

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    Molecular and functional genetic research of genes involved in inherited peripheral neuropathies. 01/01/2005 - 31/12/2008

    Abstract

    The project aims to study the molecular genetics and functional aspects of genes involved in different inherited peripheral neuropathies. The objectives are: Genotype-phenotype correlations in known and novel genes for inherited peripheral neuropathies, molecular and functional genetic research of distal hereditary motor neuropathies and of sensory neuropathies, identification of novel genes for distal hereditary motor neuropathies, sensory neuropathies, CMT2 and dominant intermediate CMT.

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    Molecular genetics and biology of Charcot-Marie-Tooth neuropathies. 01/01/2005 - 31/12/2007

    Abstract

    We aim to identify novel genes in which mutations result in known or currently unknown forms of inherited peripheral neuropathies, in particular Charcot-Marie-Tooth (CMT) disease. Over the years, we have assembled a unique collection of pedigrees, clinical data and DNA samples. In addition, the availability of the human genome project allows new opportunities to identify the disease causing genes using different molecular genetic and functional approaches. Once a gene has been identified we model the mutations in cellular systems or animal models. These tools allow the understanding of the effect of mutations on the normal functioning of the actual gene product. The observed biological mechanisms will be compared with those observed in our patients (genotype/phenotype correlations) using clinical, neurophysiological and neuropathological data. In this project we will focus on the pathomechanisms of distal motor neuropathies and sensory neuropathies through different approaches.

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    Molecular genetic and functional analysis of heat shock protein 22 (HSP22) mutations associated with distal hereditary motor neuropathy. 01/10/2004 - 30/09/2008

    Abstract

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    Molecular genetic and functional research of Rho guanine nucleotide exchange factor 10 (ARHGEF10) : a new gene for hereditary peripheral neuropathy. 01/10/2004 - 30/04/2007

    Abstract

    The general aim of this project is the molecular genetic and functional characterisation of ARHGEF10 (mouse orthologue Gef1 0) , by the following stategy: 1) Genotype/ Phenotype correlations: By mutation analysis of ARHGEF1 0 in families and isolated patients with a peripheral neuropathy, we hope to find additional ARHGEF1 0 mutations. This will help us to determine if the ARHGEF1 0 mutation associated with the phenotype of family CMT -54 is unique, or if the disease spectrum associated with ARHGEF10 can be broadened and a phenotype/genotype correlation can be made. Additional ARHGEF1 0 mutations could also indicate functional domains important for ARHGEF10 functioning in the peripheral nervous system. 2) Additional expression studies of Gef10: At this moment the limited expression information of Gef1 0 that we have, is all based on embryonic tissue results. Therefore we will perform immunohistochemistry and in situ hybridisation on tissues of adult wild-type (WT) mice. This additional Gef10 expression data will greatly facilitate the histomorphological and phenotypical analysis of the Gef10-/- mouse. 3) Generating a 'fioxed' Gef10 mouse for conditional gene deletion: A LoxP flanked Gef10 mouse (Gef1OfI/fl) will be created to study the in vivo function of Gef1 0. By crossing the Gef1OfI/fl mouse with a 'deleter mouse', a total Gef10 knockout mouse (Gef10-/-) will be obtained. The Gef10fl/fl mouse also gives us the possibility to study loss-of-Gef1 0 function in a tissue-specific, temporally restricted or inducible fashion depending on the type of Cre-mouse used. 4) Phenotypic characterization of total Gef10 knockout mice: If total Gef10-/- mice are viable, the phenotypic characterization of the peripheral nervous system in these animals will of course have priority and will be compared to the human phenotype associated with the ARHGEF1 0 mutation.

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    Organisation congres :"First European and North American Charcot-Marie-Tooth Consortium Meeting". 13/09/2004 - 31/12/2004

    Abstract

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    VIB-Genotype-Phenotype correlations and identification of the gene for dominant intermediate CMT Neuropathy type C (DI-CMTC). 01/01/2004 - 31/12/2005

    Abstract

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    Molecular genetic study of distal hereditary motor neuropathies (distal HMN). 01/01/2004 - 31/12/2005

    Abstract

    Distal hereditary motor neuropathies (distal HMN) are pure motor disorders of the peripheral nervous system resulting in severe atrophy and wasting of distal limb muscles. Distal HMNs are clinically and genetically heterogeneous. So far 8 loci and 3 genes have been identified for autosomal dominant and recessive distal HMNs. Recently, we identified missense mutations in a novel gene in distal HMN-II families. Via mutation analysis of these genes in families and isolated patients with a distal HMN phenotype, we will determine the relative frequency of mutations in these genes. Importantly, mutations have so far only been reported in distal HMN patients. We will investigate if mutations in these genes are correlated with a specific phenotype or whether these genes are involved in a wider disease spectrum. We will also investigate if genetic variations have a modulating effect in the disease process of amyotrophic lateral sclerosis (ALS) by performing genetic association studies. Finally, we will perform genome wide scans in distal HMN families not linked to the known distal HMN loci.

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    Research team(s)

    VIB-Identification of the gene for dominant intermediate CMT neuropathy. 01/01/2004 - 31/12/2004

    Abstract

    Dominant Intermediate Charcot-Marie-Tooth (DI-CMT) neuropathy is a genetic and phenotypic variant of classical CMT characterized by intermediate nerve conduction velocities and histological evidence of both axonal and demyelinating features. The first locus for DI-CMT was mapped to chromosome 10q24.1-q25.1 in an Italian family (DI-CMTA) and the second locus was mapped to 19p12-p13.2 in an Australian pedigree (DI-CMTB). So far, the DI-CMT genes have not yet been identified. We mapped a novel DI-CMTC locus on 1p34-p35 in two unrelated pedigrees from Bulgaria and USA. The combined haplotype analysis in both families localized the DI-CMTC gene within a 6.3cM linkage interval on the short arm of chromosome 1. This one-year project aims at identification of the DI-CMTC gene. Through the analysis of these two families we will narrow down the critical region by in silico cloning techniques. Additional families will be screened for linkage to the DI-CMTC locus. Positional and functional candidate genes in the region will be analyzed by sequencing analysis. Nuclear families and isolated patients with a similar phenotype will be examined for pathogenic mutations. Detailed clinical and electrophysiological examinations are available in both families and will be used for genotype-phenotype correlations.

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    Molecular characterization of inherited peripheral neurpathies and related disorders: a population based study. 01/01/2004 - 31/12/2004

    Abstract

    The study aims the characterization of molecular genetic defects in known genes and the identification of novel loci and genes, that may cause Inherited Peripheral Neuropathies and related disorders, using population based approach.

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    Molecular biology of Charcot-Marie-Tooth type 2B neuropathy. 01/10/2003 - 30/09/2005

    Abstract

    Hereditary motor and sensory neuropathy type IIB (HMSN IIB) or Charcot-Marie-Tooth disease type 2B (CMT2B) is an inherited neuropathy of the peripheral nervous system, clinically characterized by sensory loss in feet and legs, with ulcero-mutilating features, and distal muscle weakness and wasting. This disease is caused by missense mutations in the small GTPase late endosomal protein RAB7. In this project we aim to reveal the normal function of RAB7 in neurons and examine how two missense mutations (L129F and V162M) in RAB7 are responsible for the CMT2B phenotype. We will examine Rab7 in vitro in neuronal cells, we will make a transgenic mice model for CMT2B and use the Yeast two-Hybrid method for the identification of proteins that interact with Rab7. In parallel with this project we perform mutation analysis for RAB7 and genes for associated proteins that are identified by Y2H, in a set of patients with distinct types of peripheral neuropathies.

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    Molecular biology of Charcot-Marie-Tooth type 2B neuropathy. 01/01/2003 - 30/09/2003

    Abstract

    Hereditary motor and sensory neuropathy type IIB (HMSN IIB) or Charcot-Marie-Tooth disease type 2B (CMT2B) is an inherited neuropathy of the peripheral nervous system (PNS). CMT2B is clinically characterized by sensory loss in feet and legs, with ulcero-mutilating features, and distal muscle weakness and wasting. The locus maps to chromosome 3q13?q22. Recently, we reduced this candidate region to 2,5 cM and found two missense mutations (L129F and V162M) in the small GTPase late endosomal protein RAB7, associated with the CMT2B phenotype in 3 extended families and 3 isolated patients. RAB7 is a key regulatory protein for aggregation and fusion of late endocytic structures in the perinuclear region. In this project we aim to reveal the normal function of RAB7 in neurons and examine how the missense mutations L129F and V162M in RAB7 are responsible for the CMT2B phenotype. EGFP- or DsRed2- tagged Rab7 wild type (wt), Rab7L129F and Rab7V162M transfected neuronal cells will be analyzed by confocal fluorescence microscopy. A GTP-overlay experiment will indicate whether the mutant Rab7 proteins show an altered affinity for GTP. By means of colocalization with specific fluorescent markers for late endosomes and lysosomes, we will examine whether the mutant Rab7 proteins differ in intracellular localization from the wt. We will examine the influence of the missense mutations on the function of Rab7 in the endosomal pathway by investigation of the transport of sphingolipids to the Golgi-apparatus, the accessibility of lysosomes for endocytic proteins and the acidity of the lysosomes compared to the Rab7wt. We will also make transgenic mice models for CMT2B, by overexpression of constructs with Rab7wt, Rab7L129F or Rab7V162M in the nervous system. Electrophysiological, morphological, immunohistochemical and behavioural investigations will enable us to compare the phenotype of the trangenic mice with the phenotype of CMT2B patients. We will examine the expression of Rab7 in the PNS at different stages of the embryonic development. Nerves of the transgenic animals will be analyzed for the distribution, structure and quantity of late endocytic structures in the neurons. In the second term of the project we will identify proteins that interact with Rab7 using the Yeast two-Hybrid method. Rab7wt, Rab7L129F and Rab7V162M will act as `bait'. As `prey' a mouse cDNA-library of the central nervous system (blind approach) or cDNA of functional candidate proteins (candidate approach) will be used. Rab7-interacting proteins are candidate genes for other peripheral neuropathies. Finally we will perform mutation analysis for RAB7 and genes for associated proteins that are identified by Y2H, in a set of patients with distinct types of peripheral neuropathies

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      Study of the molecular pathology of inherited peripheral neuropathies and related disorders. (A. JORDANOVA, Bulgarije) 16/11/2002 - 15/11/2003

      Abstract

      The research fellowship of Dr. Albena Jordanova, PhD, relates to the ending IUAP programme P4/17 on "Genetics of normal and abnormal differentiation (Genetica van normale en abnormale differentiatie)", in which Prof. Dr. C. Van Broeckhoven, head of the Molecular Genetics Laboratory at the University of Antwerp (UIA) is a sattelite group. This fellowship also fits into the new IUAP programme on "Molecular Genetics and Cell Biology (Moleculaire Genetica en Celbiologie)" submitted by Prof. Dr. C. Van Broeckhoven, project manager, to the University of Antwerp (UA) and DWTC in 2001. Prof. Dr. Peter De Jonghe and Prof. Dr. Vincent Timmerman are members of the steering group and responsible for the section on inherited peripheral neuropathies. Here we aim to contribute to the understanding of degeneration processes in the peripheral nervous system based on genes identified for inherited peripheral neuropathies, i.e. Charcot-Marie-Tooth disease and related disorders. Knowledge of the normal and dysfunction of these genes are expected to learn us the interaction processes of their gene products in myelin formation and maintenance.

      Researcher(s)

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      Molecular genetic and functional analysis of inherited peripheral neuropathies. 01/10/2002 - 30/09/2005

      Abstract

      The inherited peripheral neuropathies are clinical and genetical heterogeneous. This project aims at identifying new genes and pathogenic mutations for inherited peripheral neuropathies. This will result in a better understanding of the neurobiology of the peripheral nervous system, creates opportunities for better DNA diagnosis and provides possibilities to perform genotype/phenotype correlations.

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      Motor versus sensory neurons: differential gene expression to identify novel genes for inherited peripheral neuropathies. 01/10/2002 - 30/09/2004

      Abstract

      We aim to find genes that are differentially expressed in motoneurons (anterior horn cells of the spinal cord) and in sensory neurons (neurons from the dorsal root ganglia, DRG). Defining the functions and characteristics of differentially expressed genes will lead to a better knowledge of the molecular and cell biological processes responsible for the differences between motor- and sensory neurons. Differentially expressed genes that localise within candidate regions for IPN are ideal candidate genes because some types of peripheral neuropathies affect only the motoneurons (HMN) or only the sensory neurons (HSN).

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      Molecular genetics and cell biology. 01/01/2002 - 31/12/2006

      Abstract

      This network proposal has as major theme the molecular genetics and cell biology of human inherited disorders. This network groups 11 excellent research laboratories at the University of Antwerp active in molecular genetics of diseases such as Alzheimer dementia, psychiatric disorders, mental retardation, peripheral neuropathies, hearing impairment and bone disorders. The availability of the human genome sequence will not only provide the molecular geneticists new tools to accelerate their research topics (such as bioinformatics, SNPs, etc.), but also lead to functional studies of the respective disease causing genes. The post-genome era will therefore need the integration of high-throughput techniques and bio-informatics, but also collaboration with excellent cell biology laboratories in the network located at other Belgian universities.

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      Clinical and molecular genetic research of inherited peripheral neuropathies. 01/01/2002 - 31/12/2005

      Abstract

      The inherited neuropathies of the peripheral nervous system have a prevalence of 1/2500. They have been observed in populations with different ethnic background. Some patients remain asymptomatic while others become severely disabled by weakness, muscle atrophy and skeletal deformities. The inherited peripheral neuropathies are genetically very heterogeneous and probably comprise between 50-100 distinct disease entities. The identification of the underlying mutations opens avenues for better diagnosis, correct genetic counseling, prenatal and pre-implantation diagnosis. This research project aims at identifying novel genes en gene defects. The identification of the genes and functional studies of the mutated gene products will result in a better understanding of the neurobiology of the peripheral nervous system. The identification of therapeutic targets potentially has implications for the acquired neuropathies that complicate e.g. diabetes mellitus and chemotherapy.

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      Understanding neurological diseases : a molecular genetic approach. 01/01/2002 - 31/12/2004

      Abstract

      We aim to identify novel genes for Alzheimer Disease (AD), Epilepsy and Charcot-Marie-Tooth (CMT) neuropathy using multiple molecular genetic approaches. Causative genes will be identified using genome-wide scans in informative families that are not explained by mutations in known genes. Genotype/phenotype correlations are made using clinical, neurophysiological and neuropathological data. In vitro studies will be performed with novel mutations in known or newly identified genes. Efforts will be made to construct transgenic mouse models making use either of constructs containing mutations leading to an extremely severe phenotype and/or multiple transgene models. The identification of genes causing neurological diseases is the first step towards a better understanding of fundamental biological processes operating in the central and peripheral nervous system.

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      VIB-Search of a new locus for Charcot-Marie-Tooth disease with ulcero-mutilations. 01/07/2001 - 30/06/2002

      Abstract

      Ulcero-mutilating neuropathies are clinically and genetically heterogeneous. Most patients have both motor symptoms, i.e. weakness and wasting of distal muscles, and sensory symptoms such as lancinating pains and hypo-aesthesia. The most striking feature of these inherited peripheral neuropathies is the occurrence of poorly healing ulcers, sometimes leading to amputations. These ulcerations, due to sensory disturbances, are not present in all patients and they can be prevented by good foot care. Families with autosomal dominant inheritance have been classified as either hereditary motor and sensory neuropathy type 2 (HMSN type II) / Charcot-Marie-Tooth type 2B (CMT2B) or hereditary sensory neuropathy type I (HSN type I) depending on the degree of weakness. Electrophysiological studies and neuropathological examinations have documented a primarily axonal neuropathy. Two loci for ulcero-mutilating neuropathies were found by genetic linkage studies; CMT2B on chromosome 3q13-q22 and HSN I on chromosome 9q22. We previously confirmed linkage to the CMT2B locus in one Scottish family. We ascertained two new large Austrian families. In one of them, molecular genetic studies showed significant linkage to the CMT2B locus and reduced the candidate region to 10 cM. Both the CMT2B and HSN I loci could be excluded in the other family. This one-year project aims to perform a genome-wide search in an extended Austrian pedigree with ulcero-mutilating neuropathy, excluded for the known CMT and HSN loci. Positional and in silico cloning techniques will be used to identify the disease-causing gene for this new locus. Mutation analysis of positional and functional candidate genes will be performed. Other families with ulcero-mutilations will be investigated for pathogenic mutations. Detailed clinical and electrophysiological examinations will be essential to make genotype-phenotype correlations.

      Researcher(s)

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        Molecular genetic and functional research of genes involved in inherited peripheral neuropathies 01/01/2001 - 31/12/2004

        Abstract

        We study the molecular genetics and functional aspects of genes involved in different inherited peripheral neuropathies. These disorders include hereditary motor and sensory neuropathies (demyelinating and axonal forms of Charcot-Marie-Tooth disease - CMT1 and CMT2, Dejerine-Sottas Syndrome - DSS and congenital hypomyelination - CH), hereditary motor neuropathies (spinal form of Charcot-Marie-Tooth disease - distal HMN), hereditary sensory neuropathies (HSN) and hereditary recurrent neuropathies (hereditary neuropathy with liability to pressure palsies - HNPP and hereditary neuralgic amyotrophy - HNA). In this project we aim to localise novel genetic loci, to identify novel genes and disease-causing mutations, to get insights into the physiopathological mechanisms of inherited peripheral neuropathies, to understand the biology of myelination, and to develop diagnosis and treatment for the patients.

        Researcher(s)

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        Charcot-Marie-Tooth disease (CMT) : a genome wide search for new loci. 01/01/2001 - 31/12/2001

        Abstract

        Charcot-Marie-Tooth disease (CMT) is the most frequent inherited disorder of the peripheral nervous system and has an important impact on the socio-economical activities of the patients. CMT type 1 is synonymous to hereditary motor and sensory neuropathy type I (HMSN I) and CMT type 2 is HMSN type II. CMT1 or the hypertrophic form of CMT is characterised by extensive de- and remyelination of peripheral nerves. CMT2 or the neuronal form of CMT is an axonal neuropathy without extensive alterations of the myelin sheath. Four genes and genetic defects are known today for the more common CMT type 1, while only one gene has been identified very recently for CMT2. In this research grant we aim to 1) perform a genome-wide search for CMT2 loci in unlinked CMT2 families, 2) use the positional candidate gene approach to rapidly identify potential genes in the linked regions, 3) perform a mutation analysis in order to identify the gene causing mutation(s). A similar approach will be used to identify a locus for a novel type of CMT in one extended pedigree.

        Researcher(s)

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          Molecular genetics of inherited ulcero-mutilating peripheral neuropathies 01/10/2000 - 30/09/2004

          Abstract

          In this project we will try to identify de genes and gene defects responsible for ulcero-mutilating peripheral neuropathies. Two loci for ulcero-mutilating neuropathies have been described, the HSN type I locus on chromosome 9q22.1-q22.3 and the CMT2B (HMSN type IIB) locus on 3q13-q22. However the responsible genes have not been identified yet. We study five families with hereditary ulcero-mutilating neuropathy. Three of these families are linked to the CMT2B locus. In the remaining two families, the CMT2B and HSN type I loci have been excluded and the underlying gene defect will be located by a genome search. From the CMT2B candidate region, positional and functional candidate genes and EST`s will be selected. These candidates will be screened for the presence of pathogenic mutations. If pathogenic mutations are found, we will check their segregation in families and isolated patients with ulcero-mutilating neuropathies. Genotype-Phenotype correlation studies will be made based on clinical, neurophysiological and neuropathological information. In the end, functional analysis of the disease causing genes will be carried out.

          Researcher(s)

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          01/10/2000 - 30/09/2002

          Abstract

          Researcher(s)

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            Molecular genetic analysis of Bulgarian families with Charcot-Marie-Tooth (CMT) disease. 01/10/2000 - 30/06/2001

            Abstract

            Several inherited peripheral neuropathies were characterised in consanguineous Bulgarian families, e.g. hereditary motor and sensory neuropathies (HMSN) type Lohm and type Russe, and CCFDN (congenital cataract and facial dysmorfic neuropathy). Dr. A. Jordanova will screen these families with molecular genetic tools in our laboratory. Multi-generation families, in which mutations in the known myelin genes are absent, will be subjected to a genetic linkage analysis and homozygosity mapping with the aim to identify novel loci for inherited peripheral neuropathies. We will perform a genome wide scan using 800 genetic markers. These markers represent a 5 - 10 cM (centimorgan) genetic map of the entire human genome. Fragment analysis will be performed with the ABI 3700 DNA sequencer. Functional and positional candidate genes will be analysed for the presence of pathogenic mutations. Gene-prediction programms will be used to determine intron-exon boundaries. DNA sequencing of genes at the genomic and cDNA level in normal individuals and Bulgarian CMT patients will also be performed with the ABI technology. This project is in the frame of a European Consortium on Charcot-Marie-Tooth disorders, of which our laboratory is the coordinator.

            Researcher(s)

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              Molecular anatomy of the paranodal region as starting point for the identification of new disease causing genes responsible for inherited peripheral neuropathies. 01/01/2000 - 30/04/2001

              Abstract

              Schwann cells are required for the myelination of the axon in the peripheral nervous system. Due to the presence of Schwann cells and myelin, the peripheral nerve becomes divided into three regions: the nodus of Ranvier, the paranodal region (paranodus) and the internodus. Paranodus and nodus are both important regions for the peripheral nerve. The inherited peripheral neuropathies have a prevalence of 10 to 40/100.000 and are characterised by clinical and genetical heterogeneity. This project aims to characterise the molecular anatomy of the paranodus and to identify new functional and positional candidate genes responsible for inherited peripheral neuropathies. In the project we will use protein-protein interaction techniques to identify new genes in the peripheral nervous system, essential for the function of the paranodus. For the detection of protein-protein interactions we will use the Yeast Two-Hybrid technology, affinity chromatogaphy and expression cloning. Co-immunoprecipitation will be used for an initial verification of the interaction.

              Researcher(s)

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                Genetic, functional, clinical and anatomopathological research of inherited peripheral neuropathies. 06/12/1999 - 30/09/2002

                Abstract

                The inherited peripheral neuropathies belong to the most frequent neuromuscular diseases and occur in populations of different ethnic origin. Considerable genetic heterogeneity is present in hereditary motor and/or sensory neuropathies (HMSN, HMN and HSN), including Charcot-Marie-Tooth disease (CMT). This leads to considerable diagnostic problems in clinical practice. The expression of the disease phenotype is extremely variable and ranges from almost no symptoms to severe muscle wasting, atrophy and deformities of hands and feet. Some patients have, at an early stage of the disease, a severe handicap and may become wheelchair dependent. The identification of disease causing mutations in different genes will facilitate accurate diagnosis of patients with inherited peripheral neuropathies obviating the need for invasive diagnostic procedures, such as nerve biopsy. Genotype / phenotype correlations are essential for the selection of specific mutations of which the functional impact can be analyzed in cellular or transgenic animal models. In this project we aim to identify novel loci, genes and mutations responsible for different forms of inherited peripheral neuropathies and to contribute to the development of more effective treatments.

                Researcher(s)

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                  Hereditary Neuralgic Amyotrophy (HNA): Identification of the genetic defect by positional cloning. 01/01/1999 - 31/12/1999

                  Abstract

                  Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant recurrent focal neuropathy. HNA patients have episodes of painful brachial plexus neuropathy with muscle weakness and atrophy. Minor dysmorphic features can be present, but these do not always segregate with the disease phenotype. We described a large HNA family showing significant linkage to chromosome 17q24-q25 and defined a candidate region of 16 cM. Genetic analysis of 6 new HNA-families allowed us recently to narrow down the HNA-candidate region to a 9,3 cM interval between the flanking markers D17S785 and D17S836. A North American group defined a HNA-candidate region that overlaps our region and allows to construct a minimal HNA candidate region of 3,5 cM, between the markers D17S785 and D17S802. In addition we have excluded two candidate genes, a putative sialyltransferase and the SFRS2 splicing factor by direct DNA sequencing in our HNA-families. The aims of the proposed research project are: 1. the construction of a clone contig of the latest HNA-candidate region, 2. the mapping of positional and functional candidate genes on the clone contig, 3. the identification of new genes in the HNA-region, and 4. the mutation analysis of genes identified by 2. and 3. through direct DNA sequencing in members of our HNA-families, in order to identify the causative genetic defect.

                  Researcher(s)

                  Research team(s)

                    Molecular genetic analysis of the brachial plexus neuropathy (Hereditary Neuralgic Amyotrophy, HNA). 01/10/1998 - 30/09/2000

                    Abstract

                    HNA is a rare autosomal dominant neuropathy characterised by episodes of attacks of pain followed by muscle weakness and sensory disturbances due to brachial plexus neuritis. Recently, a genetic linkage study in two American HNA families suggested a HNA locus on chromosome 17q. Segregation analysis of STR markers in a Turkish pedigree refined the HNA locus to a 16 cM region on chromosome 17q24-25. In this IWETO research, we aim to identify the HNA gene / mutation. After refinement of the HNA locus we will construct a physical map of the minimal linkage region using yeast artificial chromosomes (YACs). The YAC-contig will be subcloned in sCOGH cosmids. After exontrapping or direct cDNA selection on this cosmid library, mutation analysis on the subtracted genes may lead to the identification of the HNA gene. This will lead to a better understanding of the HNA aetiology and related peripheral neuropathies and provide a DNA diagnosis for HNA patients and asymptomatic individuals.

                    Researcher(s)

                    Research team(s)

                      DNA pooling as new method to perform genome searches for loci involved in inherited peripheral neuropathies. 01/10/1998 - 31/12/1999

                      Abstract

                      Genome searches are essential to map disease loci and genes in the human genome. Several families with inherited peripheral neuropathies have been sampled. Clinical, neurophysiological and histopathological studies were performed. An important reduction in the PCR reactions and gels for fragment analysis in genome searches are obtained by using a DNA pooling method. This method aims to pool DNA samples from patients of a same family and pooling DNA samples of their healthy relatives. Afterwards a PCR reaction is performed with informative DNA markers spread over the whole human genome. Finally, significant results are checked by genetic linkage studies in the whole family in order to confirm or exclude linkage.

                      Researcher(s)

                      Research team(s)

                        VIB-Positional cloning of Charcot-Marie-Tooth type 2 (CMT2). 01/01/1998 - 31/12/1998

                        Abstract

                        Charcot-Marie-Tooth disease (CMT) is the most frequent inherited disorder of the peripheral nervous system. CMT type 2 is the neuronal form of CMT without alterations of the myelin sheath. No genes have been identified for CMT2. This research grant aims to 1) confirm the known CMT2 loci that have been mapped on chromosomes l, 3, 7 and X, 2) perform a genome -wide search for the CMT2 loci in unlinked CMT2 families, 3) construct physical maps of the linked regions in order to isolate gene(s), 4) mutation analysis of positional and functional candidate genes in order to identify the disease causing mutation(s).

                        Researcher(s)

                        Research team(s)

                          A genome-wide search for the gene(s) responsible for Charcot-Marie-Tooth type 2 (CMT2). 01/04/1997 - 31/03/1999

                          Abstract

                          This project is a renewal of a previous project with the aim to identify a gene or genes reponsible for Charcot-Marie-Tooth type 2 (CMT2) disease or the axonal form of CMT. A genome-wide search will be performed with highly polymorphic DNA markers. Once a localisation if found, molecular genetic studies will be performed to identify the gene and mutation responsible for this disease.

                          Researcher(s)

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                            Molecular genetical and functional analysis of genes involved in hereditary motor and/or sensory neuropathies. 01/01/1997 - 31/12/2000

                            Abstract

                            In this project we will use a genome-wide search for genes involved in the different forms of Charcot-Marie-Tooth neuropathy. Also, we will use cellular and animal models to examine the role of disease genes in the neuropathy. Special attention will be given to the myeline Po gene.

                            Researcher(s)

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                              Positional cloning of distal hereditary motor neuropathy type II (distal HMN II). 01/01/1997 - 31/12/1997

                              Abstract

                              The distal hereditary motor neuropathy type II (distal HMN II) or the spinal form of Charcot-Marie-Tooth (CMT) is a rare disorder of the peripheral nervous system. In 1996, we found genetic linkage to chromosome 12q24 in a Belgian distal HMN II family. This project aims to identify the gene defect responsible for the distal HMN II phenotype. To assemble a clone contig of the distal HMN II region, we use yeast artificial chromosomes (YACs), P1-phage derived artificial chromosomes (PACs), cosmids, radiation hybrids (RH) and pulsed field gel electrophoresis (PFGE). Also, positional and functional candidate genes will be analysed for the presence of mutations.

                              Researcher(s)

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                                Molecular genetic research of Charcot-Marie-Tooth neuropathy and related disorders. 05/12/1996 - 05/12/1999

                                Abstract

                                This project aims at localizing the gene of genes for Charcot-Marie-Tooth disease type 2, a peripheral neuropathy. Once the chromosomal location is known, we will use molecular genetic techniques to identify the gene and gene mutation.

                                Researcher(s)

                                Research team(s)

                                  Molecular genetic analysis of the brachial plexus neuropathy (Hereditary Neuralgic Amyotrophy, HNA). 01/10/1996 - 30/09/1998

                                  Abstract

                                  HNA is a rare autosomal dominant neuropathy characterised by episodes of attacks of pain followed by muscle weakness and sensory disturbances due to brachial plexus neuritis. Recently, a genetic linkage study in two American HNA families suggested a HNA locus on chromosome 17q. Segregation analysis of STR markers in a Turkish pedigree refined the HNA locus to a 16 cM region on chromosome 17q24-25. In this research, we aim to identify the HNA gene / mutation. After refinement of the HNA locus we will construct a physical map of the minimal linkage region using yeast artificial chromosomes (YACs). The YAC-contig will be subcloned in sCOGH cosmids. After exontrapping or direct cDNA selection on this cosmid library, mutation analysis on the subtracted genes may lead to the identification of the HNA gene. This will lead to a better understanding of the HNA aetiology and related peripheral neuropathies and provide a DNA diagnosis for HNA patients and asymptomatic individuals.

                                  Researcher(s)

                                  Research team(s)

                                    Positional cloning of the neuronal and spinal forms of Charcot-Marie-Tooth neuropathy. 01/07/1996 - 31/12/2001

                                    Abstract

                                    The project aims at cloning the disease genes for the spinal and neuronal forms of Charcot-Marie-Tooth neuropathy, using a positional cloning approach. First, the gene is localised to a specific chromosonal area by segregation studies in disease families. Second, the gene is cloned using recombinant DNA technology.

                                    Researcher(s)

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                                      Functional analysis of mutations in the myelin gene Po associated with Charcot-Marie-Tooth disease, type I. 01/01/1996 - 31/12/1996

                                      Abstract

                                      Different mutations were detected in the myeline gene Po responsible for Charcot-Marie-Tooth neuropathy, type I. This project aims to study the effect of these mutations on normal functioning of the Po protein and this in relation to the disease pathology.

                                      Researcher(s)

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                                        A genome-wide search for the gene(s) responsible for Charcot-Marie-Tooth neuropathy type 2. 01/04/1995 - 31/03/1997

                                        Abstract

                                        This project aims at the identification of a gene (or genes) for Charcot-Marie-Tooth neuropathie type 2, a peripethal nervous system degenerative disease. A genome-wide search will be performed using highly polymorphic DNA markers. Once a localisation is found molecular genetic techniques will be applied to identify the gene and mutation responsible for this disease.

                                        Researcher(s)

                                        Research team(s)

                                          A genome-wide search for the distal hereditary motor neuropathy gene. 01/01/1994 - 31/12/1994

                                          Abstract

                                          In order to localize the gene for distal hereditary motor neuropathy type II (distal HMN II), we plan a random search of the whole human genome using preferably highly informative DNA markers. We would like to perform this genome-wide search with the facilities of the Human Genome Research Centre, Généthon in Paris.

                                          Researcher(s)

                                          Research team(s)

                                            Positional cloning of Charcot-Marie-Tooth neuropathy, type 2. 01/10/1993 - 05/12/1996

                                            Abstract

                                            This project aims at localizing the gene of genes for Charcot-Marie-Tooth disease type 2, a peripheral neuropathy. Once the chromosomal location is known, we will use molecular genetic techniques to identify the gene and gene mutation.

                                            Researcher(s)

                                            Research team(s)

                                              Linkage analysis of the Charcot-Marie-Tooth disease with genetic DNA markers. 01/10/1991 - 28/02/1993

                                              Abstract

                                              The Charcot-Marie-Tooth type 1a (CMT1a) disease or hereditary motor and sensory neuropathy type Ia is characterized by extensive de- and remyelination with highly reduced nerve conduction velocities. We try to localize the CMT1a gene on chromosome 17p11.2-p12 more precisely by using restriction fragment length polymorphisms, linkage analysis and pulsed field gelelectrophoresis.

                                              Researcher(s)

                                              Research team(s)

                                                Linkage analysis of the Charcot-Marie-Tooth disease with genetic DNA markers. 01/10/1990 - 30/09/1991

                                                Abstract

                                                The Charcot-Marie-Tooth type 1a (CMT1a) disease or hereditary motor abd sensory neuropathy type Ia is characterized by extensive de- and remyelination with highly reduced nerve conduction velocities. We try to localize the CMTIa gene on chromosome 17p11.2-p12 more precisely by using restriction fragment lenght polymorphisms, linkage analysis and pulsed field gelelectrophoresis.

                                                Researcher(s)

                                                Research team(s)

                                                  Linkage analysis of the Charcot-Marie-Tooth disease with genetic DNA markers. 01/10/1989 - 30/09/1990

                                                  Abstract

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                                                  Research team(s)