Ongoing projects

Screening platform for peripheral neuropathies in induced pluripotent stem cell derived 2D and 3D models. 01/01/2022 - 31/12/2022

Abstract

Charcot-Marie-Tooth (CMT) neuropathies are progressive peripheral neuropathies resulting in muscle weakness and atrophy. The development of efficient therapies is complicated by the tremendous clinical and genetic heterogeneity of these incurable hereditary neuropathies. Most CMT therapeutic studies are in a laboratory or pre-clinical phase, and only one phase III clinical study was reached for the most common form CMT type 1A. So far, all therapeutic studies have been performed in specific small animal models mimicking one specific gene mutation causing a CMT disease subtype. It is only theoretically possible to create an animal model for every gene mutation that causes CMT (more than a thousand mutations), and it involves high cost and ethical objections (3R principle for the use of laboratory animals). In addition, since the disease symptoms typically only appear in (young) adulthood, complications that can arise during the development of transgenic laboratory animals and a long lead time must be taken in consideration. Moreover, the metabolism between humans and small laboratory animals differs significantly, which can have implications for determining the correct dose and the long-term effects of a drug. The iPSC technology offers a solution for this. We have recently been able to demonstrate that induced pluripotent stem cell (iPSC)-derived nerve cells from CMT type 2 patients, caused by different gene mutations, share common features. We also showed that we could partially restore progressive mitochondrial dysfunction in these iPSC neurons by means of a therapeutic molecule. The test platform developed by us consists so far of: - Measuring nerve outgrowth; - Determining the axonal transport; - Characterizing the mitochondrial dysfunction; - Phenotyping by means of microscopic techniques. SCREEN4PN aims to further optimize, build and standardize the platform, and most importantly, extend it from a 2D to a 3D cell model by introducing neuromuscular organoids (NMOs). The goal is to offer this 2D and 3D platform to the pharmaceutical industry, clinical research organizations (CROs), and academic institutions. Initially, SCREEN4PN will be a testing platform for CMT-targeted therapies, but this will be extended to other peripheral neuropathies and neuromuscular disorders. The iPSC testing platform (2D and 3D), SCREEN4PN, should significantly shorten the process for testing drug candidates and biomarkers for this diverse group of hereditary neuropathies; by a factor of 5 compared to animal research (from more than a year to 4 months). The cost of screening candidate therapeutic molecules should also be reduced by a factor of 4. The number of experiments and the experimental variability, inherent to animal research, should also reduce. The SCREEN4PN platform, consisting of patient and control-derived iPSC neurons and NMOs (2D and 3D cultures), combined with standardized assays, will benefit the pharmaceutical industry in evaluating and/or validating their therapies or biomarkers in a relevant model; not only for CMT but also for other related neuromuscular and neurodegenerative disorders. The ultimate intention is to offer this niche CRO activity to the pharmaceutical industry, CROs and academia through a Spin In or Spin Off.

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Research team(s)

Protein quality control on the outer mitochondrial membrane: characterization of a unique role of small heat shock proteins (HSPBs) 01/11/2021 - 31/10/2023

Abstract

Small heat shock proteins (HSPBs) are ATP-independent chaperones that are involved in maintaining the proteome integrity by preventing aberrant protein aggregation. They form highly dynamic, polydisperse oligomeric ensembles, and contain long intrinsically disordered regions. Experimental challenges posed by these aforementioned properties have greatly hindered our understanding of HSPBs. Unpublished work from our lab has shown that HSPBs execute an unexpected dual role in mitochondrial protein quality control. We found out that HSPBs are able to translocate to the mitochondrial intermembrane space (IMS) under basal condition where they prevent protein aggregation; however, after heat shock (42°C for 1 hour) to induce protein misfolding, they immediately translocate to the outer mitochondrial membrane (OMM) for a reason that is unknown. Remarkable is that a P182L mutant of HSPB1 (causing peripheral neuropathy) exhibits the enrichment of the HSPB1 protein on the OMM even under the basal condition, triggering mis-signaling of an unknown pathway that subsequently leads to mitochondrial dysfunctions. In this PhD proposal, I will systematically characterize the function of HSPBs on the OMM, identify their upstream regulators for immediate translocation to the OMM post heat shock and the turn of events following it, which is particularly relevant under different cellular states.

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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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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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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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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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Targeting and delineating autophagic deficits caused by small heat shock protein mutations in CMT. 01/11/2019 - 31/10/2023

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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Research team(s)

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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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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Project website

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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Past projects

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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Research team(s)

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.

Researcher(s)

Research team(s)

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.

Researcher(s)

Research team(s)

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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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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Research team(s)

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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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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VIB-Identification of potential drug targets emerging from common pathomechanisms in Charcot-Marie-Tooth disease. 01/01/2016 - 31/12/2016

Abstract

"Charcot-Marie-Tooth neuropathy type 2 (CMT2) is an inherited axonal neuropathy which is very heterogeneous both clinically and genetically. With this ABMM project we will investigate the common links between 4 of the most frequent CMT2 causal genes to identify potential therapeutic strategies. Our primary objective is to characterize the key common-signature-pathway (CSP) of axonal degeneration. For this, we will perform a proteome analysis on neurons derived from CMT2 patient inducible pluripotent stem cells. Validated CSP will be targeted using known pharmacologically active drugs."

Researcher(s)

  • Promotor: Juneja Manisha

Research team(s)

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 the wild type and mutant small heat shock protein HSPB8 in axon homeostasis. 01/01/2015 - 31/10/2016

Abstract

Our purpose is to decipher the role of HSPB8 in axonal homeostasis (axonal integrity versus degeneration) and macroautophagy in relation to the pathomechanisms of CMT neuropathies by using our recently engineered transgenic mice.

Researcher(s)

  • Promotor: Bouhy Delphine

Research team(s)

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.

Researcher(s)

Research team(s)

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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VIB-The role of ribostasis in axonal Charcot-Marie-Tooth neuropathies caused by mutant HSPB1. 01/01/2014 - 31/12/2014

Abstract

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

Researcher(s)

  • Promotor: Bouhy Delphine

Research team(s)

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.

Researcher(s)

Research team(s)

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

Researcher(s)

Research team(s)

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)

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.

Researcher(s)

Research team(s)

VIB-Use of transgenic models to dissect the pathomechanisms caused by mutant HSPB1 and HSPB8 in axonal Charcot-Marie-Tooth neuropathies. 01/01/2012 - 31/12/2012

Abstract

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

Researcher(s)

  • Promotor: Bouhy Delphine

Research team(s)

In vivo modelling of two ulcero-mutilating neuropathies in Drosophila melanogaster 01/07/2011 - 31/12/2015

Abstract

The aim of this project is to develop fruit fly models of two phenotypically similar neurodegenerative disorders of the peripheral nervous system, Charcot-Marie-Tooth type 2B and Hereditary Sensory Neuropathy type I. The wild-type and mutant versions of the responsible genes, RAB7 and SPTLC2, will be expressed in Drosophila melanogaster. This will allow us to investigate the pathomechanism of both diseases in great detail and to investigate the possibility of a shared etiology for both disorders. Moreover, the fly models can serve as screening platforms for therapeutic compounds.

Researcher(s)

Research team(s)

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.

Researcher(s)

Research team(s)

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.

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Research team(s)

Molecular biology research of HSPB8 mutations associated with hereditary motor neuropathy. 01/01/2009 - 30/09/2011

Abstract

Our main research question is why do mutations in HSPB8 predominantly affect the the peripheral neurons while the other cell types which express equally the mutant HSPB8 are spared. Small HSPs can protect the cell from stress situations by: (1) binding to unfolded proteins, (2) regulating apoptosis and (3) stabilizing the cytoskeletal network. The effects of mutation on the function and interaction properties of HSPB8 are not completely understood. Mutation in sHSPs could disrupt the interaction pathways via the formation of protein accumulation (aggregates). The biological relevance of mutant HSPB8 protein aggregation in vivo (spinal cord) still needs to be confirmed. It is plausible that mutant protein aggregation could induce changes in the neurofilament network and disturb axonal transport. The axonal transport in the peripheral neurons is essential for the retrograde and anterograde transport of proteins, cargos and vesicles along the microtubules. Spinal motor neuron consists of the longest axons which innervate the most distal muscles; it is possible that changes in the axonal cargo transport could contribute to the development of peripheral neuropathy. Despite the fact that studies of biological processes in cell culture will yield useful information, generation of animal models are essential towards understanding the pathological mechanism, and the possibility to study the effects of potential drug therapy. Of note is that an animal model, for example a mouse model, will enable us to study the two most important cell types involved in peripheral neuropathy, the neurons and Schwann cells.

Researcher(s)

  • Promotor: Irobi-Devolder Joy

Research team(s)

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)

Research team(s)

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)

Research team(s)

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.

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Research team(s)

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)

The role of the innate immune system in neurodegeneration and neuroprotection. 01/07/2008 - 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)

  • Promotor: Janssens Sophie

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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Research team(s)

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)

Research team(s)

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.

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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)

Research team(s)

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)

Research team(s)

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

Abstract

Researcher(s)

Research team(s)

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

Abstract

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Research team(s)

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

Abstract

Researcher(s)

Research team(s)

Molecular genetics and biology of mutations in small heat shock proteins HSP22 and HSP27 in relation to motor neuropathies. 01/07/2006 - 31/12/2010

Abstract

Distal hereditary motor neuropathies (distal HMN) are genetically and clinically heterogeneous diseases of the peripheral nervous system (PNS). We recently found pathogenic mutations in two small heat shock proteins HSP22 and HSP27 as a cause for distal HMN. This projects aims: 1. Genotype-phenotype correlations in distal HMN and other inherited diseases of the PNS, 2. Association studies of HSP22 and HSP27 as risk or protective factors for amyotrophic lateral sclerosis (ALS), 3. Functional analysis of HSP22 and HSP27 mutations, 4. Construction of transgenic mice overexpressing specific HSP22 and HSP27 mutations.

Researcher(s)

  • Promotor: Irobi-Devolder Joy

Research team(s)

Project website

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.

Researcher(s)

Research team(s)

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.

Researcher(s)

Research team(s)

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

Abstract

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Research team(s)

Identification of the gene for distal hereditary motor neuropathy type II. 07/12/2005 - 31/12/2006

Abstract

Distal hereditary motor neuropathies (distal HMN, MIM#158590) are pure motor disorders of the peripheral nervous system resulting in severe atrophy and wasting of distal limb muscles[1]. We recently ascertained a large Czech family with 34 affected individuals with a phenotype strikingly similar to the previously reported Belgian distal HMN II family[2]. In both families we performed a haplotype analysis and identified several recombinants reducing the locus from 5 Mb[2] to 1.7 Mb. From this refined region we excluded several genes [3;4], and recently, identified two missense mutations (K141N and K141E) occurring in the same codon, within the ¿-crystallin domain of the small heat shock protein 22 (HSP22) gene. A c.423G>C (K141N) mutation was identified in Belgian CMT-M and Czech CMT-196 pedigrees while the second mutation, c.421A>G (K141E) was found in Bulgarian AJ-12 and English CMT-355 families. Both HSP22 mutations were absent in 400 Caucasian control chromosomes. Since the Belgian/Czech and Bulgarian/English shared respectively the K141N and K141E mutations, we performed haplotype analysis, and the results suggest that all families are genetically not closely related[5]. Both mutations target the same amino acid critical for the structural and functional integrity of the sHSP ¿A-crystallin[6]. This positively charged residue, when mutated in other sHSP gene members, results in various human disorders[7],[8]. Co-immunoprecipitation showed an increased binding of both HSP22 mutants to the interacting partner HSP27. Expression of mutant HSP22 in cultured cells promoted formation of intracellular aggregates. Our findings provide further evidence that mutations in heat shock proteins play an important role in neurodegenerative disorders.

Researcher(s)

  • Promotor: Irobi-Devolder Joy

Research team(s)

Molecular biology of small heat shock protein HSP22 en HSP27 mutations in relation to distal hereditary motor neuropathies. 01/10/2005 - 31/12/2007

Abstract

Researcher(s)

  • Promotor: Irobi-Devolder Joy

Research team(s)

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).

Researcher(s)

Research team(s)

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.

Researcher(s)

Research team(s)

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.

Researcher(s)

Research team(s)

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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Research team(s)

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.

Researcher(s)

Research team(s)

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

Abstract

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Research team(s)

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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Research team(s)

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.

Researcher(s)

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.

Researcher(s)

Research team(s)

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.

Researcher(s)

Research team(s)

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.

Researcher(s)

Research team(s)

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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Research team(s)

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).

Researcher(s)

Research team(s)

Identification of new candidate genes for hereditary peripheral neuropathies, by differential gene expression in motor and sensory neurons. 01/01/2002 - 31/12/2004

Abstract

Researcher(s)

  • Promotor: Verhoeven Kristien

Research team(s)

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)

Research team(s)

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.

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Research team(s)