Research Albena Jordanova

Abstract

Many Mendelian diseases have benefited from next-generation sequencing (NGS) technologies for molecular diagnosis and gene discovery. However, the technical limitations of NGS pose a challenge for the identification of mutational mechanisms in genomic regions impenetrable by these technologies. I hypothesize that single nucleotide variants and small indels in NGS inaccessible regions, as well as structural variants, can explain a significant proportion of missing heritability in many diseases. To this end, I propose to explore such intractable genomic regions in Charcot-Marie-Tooth disease, the most common genetic affliction of the peripheral nervous system, to bridge the missing heritability gap in this disease. I will utilize long-read nanopore sequencing in a unique patient cohort to look for potentially disease-causing variants that were missed by previous NGS analyses. I will then adopt genetic and functional in vitro and in vivo approaches to characterize the identified genomic variants and ascertain the associated functional genes that most likely underlie molecular pathology. The findings of my pioneering study will highlight the contribution of new mutational classes in peripheral neurodegeneration, discover causal variants long overlooked by state-of-the-art technologies, and deliver in vivo models that might provide clues for therapeutic approaches for peripheral nerve disorders with common etiology.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Candayan Niron Ayşe

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Many Mendelian diseases have benefited from next-generation sequencing (NGS) technologies for molecular diagnosis and causal gene discovery. However, the technical limitations of NGS pose a challenge for the identification of mutational mechanisms in genomic regions impenetrable by these technologies. I hypothesize that single nucleotide variants and small indels in NGS inaccessible regions, as well as large structural variants, can explain a significant proportion of missing heritability in many diseases. To this end, I propose to explore such intractable genomic regions in Charcot-Marie-Tooth disease, the most common genetic affliction of the peripheral nervous system, to bridge the heritability gap in this disease. I will utilize long-read nanopore sequencing in a unique patient cohort to look for potentially disease-causing variants that were missed by previous NGS analyses. I will then adopt genetic and functional in vitro and in vivo approaches to characterize the identified genomic variants and ascertain the associated functional genes that most likely underlie molecular pathology. The findings of my pioneering study will highlight the contribution of new mutational classes in peripheral neurodegeneration, discover causal variants long overlooked by state-of-the-art technologies, and deliver in vivo models that might provide clues for therapeutic approaches for peripheral nerve disorders with common etiology.

Researcher(s)

• Promoter: Candayan Niron Ayşe
• Co-promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Aminoacyl-tRNA synthetases (ARS) are the largest protein family implicated in Charcot-Marie-Tooth disease (CMT), the commonest inherited peripheral neuropathy. CMT is currently incurable. Our lab reported that mutations in tyrosyl-tRNA synthetase (YARS) cause CMT. YARS catalyzes a critical step in translation, but loss of this function is not required for CMT occurrence. It remains unknown how dysregulation of such ubiquitous protein leads to a disease manifesting in a length-dependent manner and affecting the peripheral neurons (PNs) only. Our lab demonstrated presence of YARS in different neuronal compartments, where it likely executes various functions. Moreover, YARS mutations induce transcriptome and phosphorylation changes in invertebrate and vertebrate models. Using unique patient biosamples, I will investigate how whole transcriptome and specific protein profiles are spatially organized within the PNs and how these differ compared to muscle tissue. I will also explore where and how much the phosphorsignaling axis is dysregulated. Bioinformatics integration of RNA and protein datasets will guide selection of differentially regulated key molecules to be evaluated genetically and pharmacologically for their therapeutic potential in a YARS-CMT fly model. I will also explore if the YARS pathomechanism is shared with other CMT-causing ARS, broadening the impact of my findings and facilitating the development of drugs for a greater number of patients.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Malcorps Matilde

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Over the last decade, organoids emerged as an attractive middle ground between 2D cell cultures, which do not fully recapitulate the 3D environment and animal models, which pose technical and ethical limits. In particular, cerebral organoids are emerging as the next step in patient-derived in vitro models for both neurodevelopmental as well as neurodegenerative diseases. However, cerebral organoids have mostly been based on neuronal cells alone, while evidence increases that the role of non-neuronal types (microglia, astrocytes, endothelial cells) is critical in these conditions. Integration of these cell types will more closely mimic the in vivo cellular environment in health and disease and constitutes the major challenge of this project. The established neuroimmune organoid technology will find a wide range of applications as models for studying fundamental mechanisms underlying cellular biology and genetic pathophysiology as well as for efficient drug screening.

Researcher(s)

• Promoter: Sleegers Kristel
• Co-promoter: Jordanova Albena
• Co-promoter: Malysheva Valeriya
• Co-promoter: Mancuso Renzo
• Co-promoter: Weckhuysen Sarah

Research team(s)

• VIB CMN - Genetics of Alzheimer’s Disease

Project type(s)

• Research Project

Abstract

Aminoacyl-tRNA synthetases (ARS) are the largest protein family implicated in Charcot-Marie-Tooth disease (CMT), the commonest inherited peripheral neuropathy that is currently incurable. Our lab reported that mutations in tyrosyl-tRNA synthetase (YARS) cause CMT. YARS catalyzes a critical step in translation, but loss of this function is unessential for CMT. It is unknown how this ubiquitous protein leads to a disease manifesting in a length-dependent manner and affecting the peripheral neurons (PNs) only. Our lab found YARS in different neuronal compartments, where it likely executes various functions. Moreover, YARS mutations induce transcriptome and phosphorylation changes in invertebrate and vertebrate models. Using unique patient biosamples and novel spatial profiling technology, we will investigate how whole transcriptome and specific protein profiles are spatially organized within the PNs and how these differ from non-neuronal tissues within the same patient, or controls. We will also explore where and how much the phosphor-signaling axis is dysregulated. Processing and multimodal integration of RNA and protein datasets will guide selection of differentially regulated key genes to be evaluated genetically and pharmacologically for their therapeutic potential in a YARS-CMT fly model. We will also explore if the YARS pathomechanism is shared with other ARS, broadening the impact of our findings and facilitating the development of drugs for a greater number of patients.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

In 2012, our research group reported that HINT1 is associated with Charcot-Marie-Tooth neuropathy (CMT), the most common genetic disorder of the peripheral nerves. Mutations in HINT1 contribute significantly to the CMT morbidity, however, the mechanisms triggered by the loss of HINT1 function are unknown. The encoded protein is a ubiquitous purine phosphoramidase acting as a transcriptional regulator, but the physiological role of HINT1 in peripheral neurons and its connection to disease is unclear. In this project, I will take advantage of unique patient biomaterials and fly models to understand the tissue-specific nature of HINT1 neuropathy and translate this knowledge into therapeutic opportunities for CMT. I will perform an unbiased, spatially-defined differential profiling of the neuronal transcriptome at the site of CMT lesion and compare it to non-neuronal tissues from the same patients, and to controls. Endogenous HINT1 and related proteins will also be profiled in patients and controls. The bioinformatics integration of omics data will reveal components of neuronal pathways misregulated by the HINT1 deficiency and will guide selection of key molecules to be evaluated genetically and pharmacologically for their therapeutic potential in HINT1-KO fly model and patient-derived iPSC-motoneurons. Altogether, my findings will deliver mechanistic insights into the HINT1 function and related neurodegeneration, and will provide tangible opportunities for therapy development.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Ekshteyn Alexandra

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Many Mendelian diseases have benefited from next-generation sequencing (NGS) technologies for molecular diagnosis and gene discovery. However, technical limitations of NGS pose a challenge for identification of mutational mechanisms in genomic regions impenetrable by these technologies. I hypothesize that complex genomic rearrangements called structural variants (SVs) in these loci can explain a significant proportion of missing heritability in many diseases. To this end, I propose to explore the involvement of SVs in Charcot-Marie-Tooth disease (CMT), the most common genetic affliction of the peripheral nervous system. I will utilize long-read nanopore sequencing in a unique patient cohort to look for potentially disease-causing SVs. I will then adopt genetic and functional in vitro and in vivo approaches to characterize the identified genomic variants, and ascertain the associated functional genes that most likely underlie molecular pathology. The findings of my pioneering study will highlight the contribution of structural variants in peripheral neurodegeneration, discover non-conventional mutational mechanisms long overlooked by state-of-the-art technologies, and deliver in vivo models that might provide clues for therapeutic approaches for peripheral nerve disorders with common etiology.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Candayan Niron Ayşe

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

CHARCOT-MARIE-TOOTH DISEASE (CMT), ALSO KNOWN AS HEREDITARY MOTOR AND SENSORY NEUROPATHY (HMSN), IS THE MOST COMMON FORM OF INHERITED PERIPHERAL NEUROPATHY, WITH AN ESTIMATED PREVALENCE OF 1 IN 2500 INDIVIDUALS, EQUATING TO APPROXIMATELY 125,000 PEOPLE IN THE UNITED STATES. CMT SPECIFICALLY TARGETS PERIPHERAL NERVES AND IS CHARACTERIZED BY WEAKNESS AND WASTING OF THE DISTAL LIMB MUSCLES LEADING TO PROGRESSIVE MOTOR IMPAIRMENT, SENSORY LOSS, AND SKELETAL DEFORMITIES. NO CURATIVE THERAPY IS AVAILABLE FOR CMT PATIENTS. THE LARGEST GENE FAMILY IMPLICATED IN CMT ENCODES AMINOACYL-TRNA SYNTHETASES (AARSS), WHICH ARE ESSENTIAL ENZYMES CATALYZING A KEY REACTION IN PROTEIN BIOSYNTHESIS, NAMELY, THE CHARGING OF TRANSFER RNAS (TRNAS) WITH THEIR COGNATE AMINO ACIDS. SO FAR, THE CAUSALITY BETWEEN DOMINANT AARS MUTATIONS AND CMT HAS BEEN FIRMLY ESTABLISHED IN 5 FAMILY MEMBERS (YARS1, GARS1, AARS1, HARS1, AND WARS1). DESPITE SOME HETEROGENEITIES, CLINICAL PRESENTATIONS OF CMT PATIENTS WITH AARSS MUTATIONS ARE HIGHLY SIMILAR, IMPLYING SHARED DISEASE MECHANISMS. NOTABLY, WE AND OTHERS HAVE DEMONSTRATED THAT CMT-CAUSING MUTATIONS DO NOT NECESSARILY AFFECT THE TRNA AMINOACYLATION FUNCTION OF THE ENZYMES. INSTEAD, A POTENTIALLY COMMON NEUROTOXIC GAIN OF FUNCTION IS THOUGHT TO BE RESPONSIBLE FOR THE NEUROPATHY, HOWEVER, ITS MOLECULAR BASIS REMAINS LARGELY ELUSIVE. IN THIS PROPOSAL, WE AIM TO TEST A UNIFYING CENTRAL HYPOTHESIS THAT DYSREGULATION OF A NEW ARM OF THE INTEGRATED STRESS RESPONSE (ISR), SPECIFICALLY REGULATED BY AARSS IN THE NUCLEUS, CONTRIBUTES TO THE ETIOLOGY OF CMT. WE PROPOSE THAT THIS NEW ARM OF ISR IS RELATED TO - BUT DISTINCT FROM - THE CLASSICAL EIF2A PHOSPHORYLATION MEDIATED ISR PATHWAY. BECAUSE OF THE DIFFERENT TIMELINE OF THIS STRESS RESPONSE, WE NAME IT THE LATE INTEGRATES STRESS RESPONSE (LISR). WE SPECULATE THAT CMT-LINKED AARSS MIGHT ALL BE LISR-REGULATING AARSS AND THAT DYSREGULATION OF THE CELLULAR STRESS RESPONSE SYSTEM BY CMT MUTATIONS RESULTS IN NEURODEGENERATION. THE PROJECT WILL BE CARRIED OUT IN CLOSE COLLABORATION BETWEEN YANG AND JORDANOVA LABS TO EXPLORE THE SHARED MOLECULAR MECHANISM BY WHICH DOMINANT MUTATIONS IN 5 DIFFERENT AARSS CAUSE CMT. OUR EXPLORATION WILL DIRECT FUTURE IN-DEPTH MECHANISTIC STUDIES AND DRUG DEVELOPMENT PROGRAMS FOR THIS SEVERE DISEASE. MOREOVER, THIS PROJECT WILL ADVANCE OUR UNDERSTANDING OF BASIC BIOLOGY THROUGH ESTABLISHING A NEW STRESS RESPONSE PATHWAY SPECIALLY REGULATED BY AARSS.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth disease (CMT) is caused by dying-back degeneration of peripheral neurons (PNs). Dominant mutations in aminoacyl-tRNA synthetases (ARS) lead to CMT. ARS are essential for protein biosynthesis, however loss of aminoacylation is not the disease mechanism. By studying the tyrosyl-tRNA synthetase (YARS), we aim to understand why and how defects in indispensable ARS proteins specifically affect PNs. In unique neuronal and non-neuronal patient-derived biopsies we will perform spatial characterization of their RNA and protein signatures. Key molecules identified in patient biopsies will be validated as therapeutic targets in vivo in Drosophila. Our study will address the tissue specificity of YARS- CMT and uncover strategies for curing neurodegeneration. The gained knowledge might apply to other ARS- related neuropathies and other neurodegenerative disorders.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth neuropathies (CMT) represent the most common neuromuscular disorder. CMT is currently incurable, while the symptomatic treatment cannot alleviate the main symptoms of patients. Therefore, a better understanding of the disease pathomechanisms and generation of efficient drugs are urgently needed. We reported that Dominant Intermediate CMT type C (DI-CMTC) is caused by mutations in the tyrosyl-tRNA synthetase (YARS)2. To dissect the molecular mechanisms underlying YARS-related CMT, my host lab generated and characterized Drosophila models for DI-CMTC, which reproduced the cellular and molecular hallmarks of disease pathology in humans.. In frame of this project, we will characterize the signaling state of CMT-(SHSY-5Y and iPSC) neurons not only via classical morphological and functional parameters but we also aim to establish their signaling status in a spatially resolved manner. Specifically, I envisage to evaluate the subcellular protein and mRNA localization of YARS and putative YARS interactors with Digital Spatial Profiling (DSP, Nanostring Technologies) of CMT-neurons. Given that I am interested in both the phosphorylation- and mRNA-expression signature of CMT-MNs, this technique seems to be ideally suited for my purpose.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: Petrovic-Erfurth Maria-Luise

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

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.

Researcher(s)

• Promoter: De Vos Winnok
• Co-promoter: Caljon Guy
• Co-promoter: De Meyer Guido
• Co-promoter: Jordanova Albena
• Co-promoter: Rademakers Rosa
• Co-promoter: Timmerman Vincent
• Co-promoter: Timmermans Jean-Pierre
• Co-promoter: Vissenberg Kris
• Co-promoter: Weckhuysen Sarah

Research team(s)

• Laboratory of cell biology and histology

Project type(s)

• Research Project

Abstract

Aminoacyl-tRNA synthetases (ARS) are the largest protein family implicated in Charcot-Marie-Tooth disease (CMT), the commonest inherited peripheral neuropathy. We reported that mutations in tyrosyl-tRNA synthetase (YARS) cause Dominant Intermediate CMT type C (DI-CMTC). ARS are ubiquitous enzymes essential for protein biosynthesis. It is unknown which cellular mechanisms are triggered by the mutant enzymes and how this causes neurodegeneration. To gain pathomechanistic insights, we established Drosophila and neuroblastoma models and performed extensive genetic, transcriptomics and biochemical studies. We discovered unique DI-CMTC signatures suggesting that imbalance in phosphor-signaling might underlie the neuropathy. Here, we aim to establish how YARS interacts with phosphor-signaling and to validate our exciting preliminary findings in the most disease-relevant cell model, the patient-derived motoneurons. Next to in-depth mo hological and functional characterization, we will assess their phosphorylation and transcription profiles. We will integrate and match our findings to reconstruct the cellular mechanisms affected by mutant YARS and to pinpoint molecular targets for further manipulation. Finally, we will attempt to pharmacologically reverse the identified disease signatures in the motoneurons to provide a proof of concept for therapy development. Our study will provide mechanistic insights on DI-CMTC and will give tangible clues for designing therapeutic strategies.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth neuropathies (CMT) are severe and incurable disorders, representing the most common genetic affliction of PNs. Autosomal recessive CMT forms (ARCMT) have an earlier onset and a more severe disease cause. Molecular genetics and biology of ARCMT, as CMT in general, is poorly understood due to the extensive genetic and pathophysiological heterogeneity. The diversity of gene functions known so far make CMT an ideal paradigm to study the mechanistic basis of peripheral neurons homeostasis and dysfunction. In this project, we will study a cohort of 135 ARCMT families using exome sequencing, positional cloning, bioinformatics and functional genomics in Drosophila models in order to identify new putative ARCMT genes and their interactions' patterns. Our findings will: i) pinpoint genes maintaining PNS homeostasis in health and disease; ii) highlight relationships between causal genes; iii) unravel novel pathomechanisms of neurodegeneration or strengthen the importance of known ones; iv) give clues to predict phenotypic outcome in response to different genetic background; v) deliver disease models suitable for therapeutic applications; vi) improve the molecular diagnosis, prognosis and prevention of CMT neuropathies. The knowledge gained will be relevant not only to CMT, but will potentially make a larger contribution in the understanding and treatment of other inherited or acquired neurodegenerative disorders.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Armirola Ricaurte Maria Camila

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth neuropathies (CMT) represent the most common neuromuscular disorder. CMT is currently incurable, while the symptomatic treatment cannot alleviate the main symptoms of patients. Therefore, a better understanding of the disease pathomechanisms and generation of efficient drugs are urgently needed. We reported that Dominant Intermediate CMT type C (DI-CMTC) is caused by mutations in the tyrosyl-tRNA synthetase (YARS)2. To dissect the molecular mechanisms underlying YARS-related CMT, my host lab generated and characterized Drosophila models for DI-CMTC, which reproduced the cellular and molecular hallmarks of disease pathology in humans.. In frame of this project, we will characterize the signaling state of CMT-(SHSY-5Y and iPSC) neurons not only via classical morphological and functional parameters but we also aim to establish their signaling status in a spatially resolved manner. Specifically, I envisage to evaluate the subcellular protein and mRNA localization of YARS and putative YARS interactors with Digital Spatial Profiling (DSP, Nanostring Technologies) of CMT-neurons. Given that I am interested in both the phosphorylation- and mRNA-expression signature of CMT-MNs, this technique seems to be ideally suited for my purpose.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: Petrovic-Erfurth Maria-Luise

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Aminoacyl-tRNA synthetases (ARS) are the largest family of proteins implicated in Charcot-Marie- Tooth disease (CMT), the most common inherited peripheral neuropathy. CMT is a life-long and incurable disease. ARS are ubiquitous essential enzymes normally required for protein biosynthesis. However, in neurodegeneration, a distinct unknown cellular mechanism triggered by the CMT mutations in ARS is at play. We have established Drosophila and cellular CMT models and studied the pathways altered in presence of mutations in tyrosyl-tRNA synthetase (YARS). By utilizing these models in a complimentary manner, we have solid evidence that dysregulated phosphor-signaling might underlie ARS-related CMT. Here, I propose to translate these exciting findings from flies and neuroblastoma cells to human motorneurons (MNs), the primary cell type affected by the CMT-ARS mutations. I will establish iPSC derived MNs from YARS-CMT patients and will assess spatially and quantitatively their phosphorylation profile. Then I will attempt to pharmacologically revert the disease profile signatures to healthy state. Thereby, I will not only provide a proof of concept for future CMT therapies, but will also characterize a novel role of the YARS protein in phosphor-signaling.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Petrovic-Erfurth Maria-Luise

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

In 2012, our research group reported that HINT1 is associated with Charcot-Marie-Tooth neuropathy (CMT), the most common genetic disorder of the peripheral nerve. The HINT1 enzyme catalyzes the hydrolysis of purine phosphoramidases and all CMT-causing mutations result in a loss of its function. Mutations in HINT1 contribute significantly to the CMT morbidity, however, the physiological role of HINT1 in peripheral neurons and its connection to disease are unclear. In this project, I will create and characterize HINT1 patient-derived motor neurons in order to identify disease-related signatures. To this end, I will make use of transcriptomic profiling, coupled with indepth morphological characterization and functional analyses, including electrophysiological investigations. These findings will allow me to construct the HINT1 regulatory network in neuronal cells. Finally, I will attempt to pharmacologically reverse the identified disease signature(s) in the patient-derived motor neurons to provide proof-of-concept for future therapy development. As a whole, this study will decipher the fundamental role of HINT1 in neuronal homeostasis, will provide mechanistic insights on HINT1-related CMT, and will give tangible clues for designing therapeutic strategies.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Peeters Kristien

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth disease is an incurable hereditary neurodegenerative disorder characterized by severe and progressive sensori-motor deficits. More than 80 genes have been described to cause this pathology and among them there are 6 aminoacyl tRNA-synthetases (ARS) rendering them a prominent CMT-causing genes family. Interestingly, all the mutations lead to an axonal phenotype. ARS are ubiquitously expressed enzyme involved in the initial step of protein biosynthesis, therefore they are indispensable for cell viability. So far, it still remains mysterious how molecular defects in these proteins could cause neurodegeneration with the same spectrum of neuropathic symptoms. My project is to investigate if there is an existence of a common toxic pathway in mutant ARS associated with CMT. I will employ a unique combination of experimental approaches (cell biology, proteomics, microscopy, Drosophila genetics and behavioral assay) using experiment tools (human neuroblastoma cells and Drosophila fly model) to systematically dissect the ARS proteins network and to identify a common pathogenic pathway involved in CMT. Based on the mechanistic insight, I will provide new model to study CMT and a new concept to alleviate mutant-specific neurodegenerative phenotypes. Ultimately, my findings can be extended to other acquired and inherited neuropathies and will facilitate the development of pharmacological strategies for the treatment of these debilitating disease.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: Petrovic-Erfurth Maria-Luise
• Fellow: Morant Laura

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth (CMT) neuropathy is the most common inherited neuromuscular disorder in humans. The disease is characterized by progressive muscle atrophy, sensory loss and bone deformities. The treatment of CMT patients is only supportive, as there are no drugs able to halt or slow the disease progression. Four different aminoacyl-tRNA synthetases are etiologically linked to CMT and mutations in one of them – tyrosyl-tRNA synthetase (YARS) – cause Dominant Intermediate CMT type C (DI-CMTC). In this project, I will use the Drosophila DI-CMTC model, which closely resembles the disease hallmarks, as a platform for preclinical drug discovery in CMT. Using this in vivo tool, I will test the pharmacological effect of small molecules with established safety profiles in humans. The compounds will be initially screened for their ability to suppress the fly developmental lethality caused by ubiquitous expression of one of the DI-CMTC-causing alleles (E196K) in YARS. Further validation assays will pinpoint the most potent drug candidates, able to rescue two different neuron-specific phenotypes in the mutant flies and therefore biologically relevant to the disease. Drosophila has only recently gained popularity in drug development and similar drug screenings have not been performed in CMT. This proof-of-concept study will pinpoint pertinent drug candidates having the potential to cure DI-CMTC and with prospective therapeutic effects on other forms of inherited or acquired neuropathies.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

In 2012, our research group reported that HINT1 is associated with Charcot-Marie-Tooth neuropathy (CMT), the most common genetic disorder of the peripheral nerves. Mutations in HINT1 contribute significantly to the CMT morbidity, however, the mechanisms triggered by the loss of HINT1 function are unknown. The encoded protein is a purine phosphoramidase, but the physiological role of HINT1 in neurons and its connection to disease is unclear. In this project, we will take advantage of the evolutionary conservation of HINT1 function and will integrate studies in yeast and human cells to understand how mutations in HINT1 lead to CMT. In a genetic complementation screen we will search for neuronally-expressed human genes rescuing Hnt1 deficiency in yeast. Also, we will create and characterize patient-derived motor neurons and will perform transcriptomics on them to identify disease-specific mis-regulated transcripts. The results obtained with these complementary approaches will allow us to build the HINT1 regulatory network in neuronal cells. Finally, we will pharmacologically target druggable components of the HINT1 network to provide a proof of concept. Altogether, this study will decipher the fundamental role of HINT1 in neuronal homeostasis, will provide mechanistic insights on HINT1-related CMT, and will give tangible clues for designing therapeutic strategies.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Dominant intermediate Charcot-Marie-Tooth disease type C (DI-CMTC) is an incurable hereditary neurodegenerative disorder characterized by severe and progressive sensory-motor deficits. DICMTC is caused by mutations in the tyrosyl-tRNA synthetase (YARS), an essential enzyme involved in the initial steps of protein biosynthesis and therefore indispensable for cell viability. It remains enigmatic how molecular defects in this housekeeper protein could cause degeneration restricted to peripheral nerves. Our goal is to unravel the molecular mechanisms underlying YARS neurotoxicity and to translate these findings into potential pharmacological therapies for DI-CMTC. I will employ a combination of systematic "omics" approaches (proteomics, interactomics, functional genomics) and unique experimental tools (Drosophila and neuroblastoma genetic models) in order to unravel the neuronal signaling response elicited by mutant YARS proteins. The identified key molecular players will be functionally characterized and used to alleviate mutantspecific neurodegenerative phenotypes in the only existing animal model of DI-CMTC (Drosophila melanogaster). Ultimately, my findings can be extended to other inherited or acquired neuropathies and will facilitate the development of pharmacological strategies for the treatment of these debilitating diseases.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Petrovic-Erfurth Maria-Luise

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

My project aims at better understanding of the molecular basis of autosomal recessive Charcot-Marie-Tooth (ARCMT) by the identification of novel causative genes. To this end, exome sequencing and bioinformatics are combined with intra- and inter-familial homozygosity mapping, haplotype sharing and linkage analyses. I am studying a large collection of nuclear ARCMT families with documented consanguinity and/or geographic or ethnic clustering, facilitating the gene hunting efforts. The novel genes may unravel novel pathomechanisms of neurodegeneration or strengthen the importance of already known ones, will create opportunities for improved molecular diagnostics, prognosis and disease prevention and possibly will pinpoint potential drug targets for treatment.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Atkinson Derek

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

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.

Researcher(s)

• Promoter: Timmermans Jean-Pierre
• Co-promoter: Adriaensen Dirk
• Co-promoter: De Meyer Guido
• Co-promoter: De Vos Winnok
• Co-promoter: D'Haese Patrick
• Co-promoter: Giugliano Michele
• Co-promoter: Jordanova Albena
• Co-promoter: Keliris Georgios A.
• Co-promoter: Knapen Dries
• Co-promoter: Maudsley Stuart
• Co-promoter: Ponsaerts Peter
• Co-promoter: Timmerman Vincent
• Co-promoter: Vissenberg Kris

Research team(s)

• Laboratory of cell biology and histology

Project type(s)

• Research Project

Abstract

In 2012, our research group reported that genetic defects in HINT1 are associated with Charcot-Marie-Tooth neuropathy (CMT), the most common inherited disorder of the peripheral nerves. Mutations in HINT1 contribute significantly to the CMT morbidity; however the molecular mechanisms triggered by the loss of HINT1 function are unknown. The encoded protein is a purine phosphoramidase, but the physiological role of HINT1 in neurons and its connection to disease is utterly undiscovered. My project aims to understand how mutations in HINT1 lead to neurodegeneration and to translate this knowledge into therapeutic opportunities for peripheral neuropathies. The study will be performed in the Molecular Neurogenomics group led by Prof. Albena Jordanova at the VIB Department of Molecular Genetics, University of Antwerp. Taking advantage of the evolutionary conservation of HINT1 function, I will integrate studies in yeast and patient-derived model systems to identify the genetic and functional interactors of this protein. Hnt1-deficient yeasts grow normally at physiological conditions, but have reduced viability under stress. Thus, this organism has compensatory mechanisms rescuing the Hnt1 dysfunction. Similar alternative mechanisms might exist in mammals and their identification offers particular translational advantages. In a large-scale genetic complementation study, I will search for neuronally-expressed human genes rescuing the Hnt1 deficiency in yeast. The suppressor screen will be supplemented with RNA sequencing of induced neurons established from HINT1 patients. Their expression profiling will uncover neuronal transcripts mis-regulated in a disease-specific manner. The results obtained with these complementary approaches will allow me to implicate HINT1 in a network of cellular pathways and, simultaneously, to explore compensatory mechanisms that counteract the pathological effects of HINT1 deficiency. I will pharmacologically target in yeast the most suitable protein hits coming out of my combined screenings, as to provide a proof of concept. Like this, I will use the yeast model not only as a genetic tool to unravel disease etiology, but also as a pre-clinical drug discovery platform for inherited peripheral neuropathies. Ultimately, my strategy will deliver mechanistic insights into HINT1-related CMT, and will provide avenues for rational drug design to treat this devastating disorder.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Amor Barris Silvia

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Aminoacyl-tRNA synthetases are essential enzymes, governing the precise translation of genetic information into proteins. Mutations in six of them lead to different subtypes of Charcot-Marie-Tooth disease (CMT), the most common inherited peripheral neuropathy. We established that Dominant Intermediate CMT type C (DI-CMTC) is caused by genetic defects in tyrosyl-tRNA synthetase (YARS). It is challenging to understand how mutations in this primordial enzyme lead to a specific neuronal degeneration. To gain insights in disease pathology, we developed a Drosophila DI-CMTC model, which successfully recapitulated several hallmarks of CMT pathophysiology. Here, we will use this model to validate the hypothesis that neuronal toxicity of YARS is exerted in the nucleus, where DI-CMTC mutations interfere with an ex-translational function of this protein. We will combine different "omics" approaches to identify regulatory networks and pathways of neurotoxicity triggered by the DI-CMTC mutations in the nucleus. Subsequently, the effect of their therapeutic targeting will be evaluated in an in vivo chemical genetic screen in Drosophila. In this way, we will use our fly DI-CMTC model not only as a genetic tool to unravel disease mechanisms, but also as a preclinical platform for CMT drug discovery. Our findings will contribute to a better understanding of the fundamental role of tRNA synthetases in organismal biology, will provide mechanistic insights on the neurodegenerative process associated with DI-CMTC and other disorders with common etiology, and will open avenues for the development of novel treatment strategies for CMT patients.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Palaima Paulius

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

We aim to generate a more complete understanding of the molecular basis of dying back axonal degeneration by identification of genes causing CMT and HSP. Using single-gene mutations as perturbations, we will provide a direct route to the biology of these devastating disorders and subsequent clinical translation.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Estrada Alejandro

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

My project aims at better understanding of the molecular basis of autosomal recessive Charcot-Marie-Tooth (ARCMT) by the identification of novel causative genes. To this end, exome sequencing and bioinformatics are combined with intra- and inter-familial homozygosity mapping, haplotype sharing and linkage analyses. I am studying a large collection of nuclear ARCMT families with documented consanguinity and/or geographic or ethnic clustering, facilitating the gene hunting efforts. The novel genes may unravel novel pathomechanisms of neurodegeneration or strengthen the importance of already known ones, will create opportunities for improved molecular diagnostics, prognosis and disease prevention and possibly will pinpoint potential drug targets for treatment.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Atkinson Derek

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Aminoacyl-tRNA synthetases are essential enzymes, governing the precise translation of genetic information into proteins. Mutations in four of them lead to different subtypes of Charcot-Marie-Tooth disease (CMT), the most common inherited peripheral neuropathy. We established that Dominant Intermediate CMT type C (DI-CMTC) is caused by genetic defects in the tyrosyl-tRNA synthetase (YARS). It is challenging to understand how mutations in this primordial enzyme lead to a specific neuronal degeneration. To gain insights in disease pathology, we developed a Drosophila DI-CMTC model, which successfully recapitulated several hallmarks of CMT pathophysiology. Here, we will use this model as a functional platform to validate the hypothesis that neuronal toxicity of YARS is exerted in the nucleus, where DI-CMTC mutations interfere with an extranslational function of this protein. Supported by exciting preliminary data, we will combine different "omics" approaches in Drosophila and neuroblastoma cells to identify regulatory networks and pathways of neurotoxicity triggered by the DI-CMTC mutations in the nucleus. Our findings will contribute to a better understanding of the fundamental role of tRNA synthetases in organismal biology, will provide mechanistic insights on the neurodegenerative process associated with DI-CMTC and other disorders with common etiology, and will open avenues for the development of novel treatment strategies for CMT patients.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Aminoacyl-tRNA synthetases are essential enzymes, governing the precise translation of genetic information into proteins. Mutations in four of them lead to different subtypes of Charcot-Marie-Tooth disease (CMT), the most common inherited peripheral neuropathy. We established that Dominant Intermediate CMT type C (DI-CMTC) is caused by genetic defects in tyrosyl-tRNA synthetase (YARS). It is challenging to understand how mutations in this primordial enzyme lead to a specific neuronal degeneration. To gain insights in disease pathology, we developed a Drosophila DI-CMTC model, which successfully recapitulated several hallmarks of CMT pathophysiology. Here, we will use this model as a functional platform to validate the hypothesis that neuronal toxicity of YARS is exerted in the nucleus, where DI-CMTC mutations interfere with an ex-translational function of this protein. Supported by exciting preliminary data, we will combine different "omics" approaches to identify regulatory networks and pathways of neurotoxicity triggered by the DI-CMTC mutations in the nucleus. Our findings will contribute to a better understanding of the fundamental role of tRNA synthetases in organismal biology, will provide mechanistic insights on the neurodegenerative process associated with DI-CMTC and other disorders with common etiology, and will open avenues for the development of novel treatment strategies for CMT patients.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Bervoets Sven

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

This proposal aims to generate a more complete understanding of the molecular architecture of peripheral nerves by unraveling the molecular basis of Charcot-Marie-Tooth disease. We will use "omics" technologies to study patients and model organisms (yeast, Drosophila, mouse), focusing on the identification of causative and modifier CMT genes and the regulatory networks which they are involved in. Armed with this library of data, we will provide cues to the mechanistic and systems basis of peripheral nerve homeostasis and dysfunction.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

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)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

My project aims at better understanding of the molecular basis of autosomal recessive Charcot-Marie-Tooth (ARCMT) by the identification of novel causative genes. To this end, exome sequencing and bioinformatics are combined with intra- and inter-familial homozygosity mapping, haplotype sharing and linkage analyses. I am studying a large collection of nuclear ARCMT families with documented consanguinity and/or geographic or ethnic clustering, facilitating the gene hunting efforts. The novel genes may unravel novel pathomechanisms of neurodegeneration or strengthen the importance of already known ones, will create opportunities for improved molecular diagnostics, prognosis and disease prevention and possibly will pinpoint potential drug targets for treatment.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Atkinson Derek

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

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

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

In this study we aim to deliver a better understanding of the molecular basis and genetic epidemiology of CMT by finding novel causative genes and performing genotype-phenotype correlations, as they offer partical advantages form a biological and translational perspective. Our unique entry point is an ethnically diverse collection of families and sporadic patients from Northeast Brazil, a geographic area not representied on the epidemiological map of Charcot-Marie-Tooth.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

The overall objective of this proposal is to generate a more complete understanding of the molecular basis of ARCMT using large-scale genetic, functional genomics and transcriptomics approaches. By focusing on the identification of causative genes and the regulatory networks their encoded products are involved, we aim to provide the most direct route to the biology of these devastating disorders and subsequent clinical translation.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

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

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

My project aims at better understanding of the molecular basis of autosomal recessive Charcot-Marie-Tooth (ARCMT) by the identification of novel causative genes. To this end, exome sequencing and bioinformatics are combined with intra- and inter-familial homozygosity mapping, haplotype sharing and linkage analyses. I am studying a large collection of nuclear ARCMT families with documented consanguinity and/or geographic or ethnic clustering, facilitating the gene hunting efforts. The novel genes may unravel novel pathomechanisms of neurodegeneration or strengthen the importance of already known ones, will create opportunities for improved molecular diagnostics, prognosis and disease prevention and possibly will pinpoint potential drug targets for treatment.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Atkinson Derek

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy and is clinically and genetically extremely heterogeneous. During the last two decades, molecular genetic studies have led to the successful identification of over 36 CMT-genes. Currently, only a few CMT-loci remain unresolved. This project addresses the identification of CMT-causing mutations and genes in two of them: DI-CMTA and CMT2G. Because of their private nature and large linkage intervals with high gene content, these loci so far represented a challenge for researchers. The immerging next generation sequencing technologies offer an attractive opportunity to tackle such orphan CMT-subtypes. Taking advantage of these new possibilities we aim to identify the disease-causing CMT-defects in DI-CMTA and CMT2G forms using whole genome sequencing. Once identified, we will search for additional pathogenic mutations in our extended collection of well characterized nuclear families affected with DI-CMT or CMT2, thus providing additional evidence for the causality of our findings. Our selected cohort will also be used for systematic screening of known DICMT/ CMT2-genes in order to delineate the mutation spectrum of both CMT-subtypes. Extensive genotypephenotype correlation will provide valuable insights concerning the clinical determinants of these entities and will aid future diagnostics and help uncover the neuropathy pathomechanisms.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: De Jonghe Peter
• Fellow: Peeters Kristien

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

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.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: Timmerman Vincent
• Fellow: Ermanoska Biljana

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

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

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

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

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

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

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Hereditary spastic paraplegias (HSP) are a group of rare neurodegenerative disorders of the upper motor neurons characterized by extreme clinical and genetic heterogeneity. The HSP disease is currently untreatable and poorly understood, warranting research on its etiology and potential targets for intervention. We aim at clarifying the biological complexity underlying this condition focusing on the identification of novel genes and disease-causing mutations involved in HSP pathogenesis. Our special "research tool" will be the unique genetic heritage of Gypsies/Roma - the largest genetic and socio-cultural isolate of Europe. Research on HSP in this unique founder population provides a substantial and yet unexplored potential, as limited genetic diversity, large traditional families and shared ancestral mutations could simplify the etiological complexity of this disease. In collaboration with the group of Prof. Ivaylo Tournev, Department of Neurology, Sofia Medical University we collected extended genealogical and clinical information of Gypsy familial and sporadic HSP cases. With this genetic material we will pursue four objectives: (i) Large scale SNP genotyping to search for disease associated loci using homozygosity mapping and linkage analysis. (ii) Patients linked to already known loci and genes will be further analyzed to identify the disease-causing mutations. (iii) Patients linked to unknown loci will be further compared to identify overlapping HSP-associated regions and shared haplotypes. Subsequently, (iv) whole exome/genome sequencing in selected individuals, (v) hit validation in patient cohorts from Gypsy and outbreed communities, and (vi) functional genomics approaches will allow identification of novel HSP genes. The results of this study should contribute to identification of novel genetic entities and to a catalogue of genes and disease-causing genetic variants causing HSP that can subsequently be genotyped in large outbreed populations. In this way, our findings will be of general relevance for the research field and will be applicable to all national health care systems. The mutation identification will allow genotype-phenotype correlations and will have an important impact on the diagnostic of spastic paraplegias, genetic counseling and disease prevention.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Most of the identified genes and loci in ARCMT have resulted from studies of large inbred families originating from particular geographic areas or specific ethnic groups (e.g. Gypsies). Although there are no reported attempts in the literature to target small families with this disease, some studies have shown that, as a proof of principle, such strategy can be successful (7, 8). Using our collection of families and by following the approach for mapping of recessive disorders together with genotyping technologies, we aim to create a powerful tool for ARCMT locus and gene identification. Furthermore, novel technologies now also allow targeting of small families.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: De Jonghe Peter
• Fellow: Zimon Magdalena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

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.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy and is clinically and genetically extremely heterogeneous. During the last two decades, molecular genetic studies have led to the successful identification of over 36 CMT-genes. Currently, only a few CMT-loci remain unresolved. This project addresses the identification of CMT-causing mutations and genes in two of them: DI-CMTA and CMT2G. Because of their private nature and large linkage intervals with high gene content, these loci so far represented a challenge for researchers. The immerging next generation sequencing technologies offer an attractive opportunity to tackle such orphan CMT-subtypes. Taking advantage of these new possibilities we aim to identify the disease-causing CMT-defects in DI-CMTA and CMT2G forms using whole genome sequencing. Once identified, we will search for additional pathogenic mutations in our extended collection of well characterized nuclear families affected with DI-CMT or CMT2, thus providing additional evidence for the causality of our findings. Our selected cohort will also be used for systematic screening of known DICMT/ CMT2-genes in order to delineate the mutation spectrum of both CMT-subtypes. Extensive genotypephenotype correlation will provide valuable insights concerning the clinical determinants of these entities and will aid future diagnostics and help uncover the neuropathy pathomechanisms.

Researcher(s)

• Promoter: De Jonghe Peter
• Promoter: Jordanova Albena
• Co-promoter: De Jonghe Peter
• Fellow: Peeters Kristien

Research team(s)

• VIB CMN - Molecular Neurogenomics
• Neurogenetics Group

Project type(s)

• Research Project

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.

Researcher(s)

• Promoter: Jordanova Albena
• Fellow: Ermanoska Biljana

Research team(s)

• VIB CMN - Molecular Neurogenomics
• Neurogenetics Group

Project type(s)

• Research Project

Abstract

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

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• Neurogenetics Group
• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Charcot-Marie-Tooth disease (CMT) is the most common human 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. Mutations in more than 30 genes have been identified in the past 15 years providing more accurate diagnosis to CMT patients. 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 slowly progressive neuropathy, intermediate nerve conduction velocities along peripheral nerves and histological evidence of both axonal and Schwann cell involvement. We were the first to describe this genetic entity and demonstrated that it is caused by different mutations in the gene coding for tyrosyl-tRNA synthetase. This study will be 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 a Drosophila model for DI-CMTC. In this way we will be able to gain original information on DI-CMTC pathomechanisms. The knowledge gained will be relevant also to other inherited and acquired neuropathies.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• VIB CMN - Molecular Neurogenomics
• Neurogenetics Group

Project type(s)

• Research Project

Abstract

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

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• Neurogenetics Group
• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

Our current hypothesis is that DI-CMTC associated mutations in YARS may result in the activation of protein degradation pathways, either directly (e.g. due to mischarging of tRNATyr and misincorporation of non-cognate amino acids in cellular proteins) or indirectly (through interfering with downstream protein quality control pathways). In both cases, this is expected to result in overload of the UPS and activation of cellular stress responses, including induction of autophagy, ER stress and ultimately apoptosis. Here, we propose to study the potential derailment of these cellular pathways in more detail.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• Neurogenetics Group

Project type(s)

• Research Project

Abstract

Most of the identified genes and loci in ARCMT have resulted from studies of large inbred families originating from particular geographic areas or specific ethnic groups (e.g. Gypsies). Although there are no reported attempts in the literature to target small families with this disease, some studies have shown that, as a proof of principle, such strategy can be successful (7, 8). Using our collection of families and by following the approach for mapping of recessive disorders together with genotyping technologies, we aim to create a powerful tool for ARCMT locus and gene identification. Furthermore, novel technologies now also allow targeting of small families.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: De Jonghe Peter
• Fellow: Zimon Magdalena

Research team(s)

• Neurogenetics Group
• VIB CMN - Molecular Neurogenomics

Project type(s)

• Research Project

Abstract

We aim to perform a large-scale study on the molecular basis or ARCMT, taking advantage of our unique collection of nuclear inbred families from different geographic regions and ethnic groups of the world. We will apply an approach of simultaneous genetic search for several trait-causing loci with large scale genotyping, that will allow identification of novel loci, genes and disease-causing mutations, respecting at the same time the genetic heterogeneity of ARCMT.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: De Jonghe Peter

Research team(s)

• VIB CMN - Molecular Neurogenomics
• Neurogenetics Group

Project website

Project type(s)

• Research Project

Abstract

Autosomal-recessive forms of Charcot-Marie-Tooth disease (ARCMT) are rare disorders of the peripheral nervous system showing extreme clinical and genetic heterogeneity. So far eleven genes and three loci have been implicated in the pathology of only a small number of ARCMT families. Most of the genes have been identified using homozygosity mapping of large inbred families, however there are no reported attempts in the literature to target small families with this disease. Finding novel loci and genes in single patients, together with identifying the disease-causing mutations in already reported genes is a major challenge for the current research and diagnostic in this field. We propose to conduct a large-scale study on the molecular basis of ARCMT, taking advantage of our unique collection of nuclear inbred families from different geographic regions and ethnic groups of the world. We will perform large scale SNP genotyping to search simultaneously for several trait-causing loci using homozygosity mapping. Our disease model ideally suits this genetic approach, because the rarer the disease the more pronounced the homozygozity effect. Patients linked to already known loci and genes will be further analysed to identify the disease-causing mutations. Patients linked to unknown loci will be further genotyped to delineate the minimal genetic region, common to all of them. Subsequent search of positional and functional candidate genes will allow identification of novel ARCMT genes. Considering the high density of the SNP array and the degree of consanguinity in the families, we estimate that our study has the potential to identify several novel ARCMT loci and genes. The identification of genes causing ARCMT will contribute to the understanding of the pathophysiology of these disorders by revealing new disease mechanisms or strengthen the importance of the known ones. The mutations that will be found will allow genotype-phenotype correlations and will have an important impact on the diagnostic of peripheral neuropathies, genetic counseling and disease prevention.

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• Neurogenetics Group

Project website

Project type(s)

• Research Project

Abstract

This study is a starting point for the creation of a unique research profile into molecular genetics of autosomal-recessive forms of Charcot-Marie-Tooth disease (ARCMT) - severe and disabling genetic disorders of the peripheral nervous system, where limited research was done so far worldwide. The identification of genes and mutations causing ARCMT will contribute to the understanding of the pathophysiology of these disorders by revealing new disease mechanisms or strengthen the importance of the known ones. This will allow genotype-phenotype correlations and will have an important impact on the diagnostic of peripheral neuropathies, genetic counseling and disease prevention. The proposed research line will add and complement to the research and diagnostic capacity and international recognition of the VIB Department of Molecular Genetics by i) implementing a specific research project that has been put on hold because of the previous lack of capacity; ii) accumulation of a critical mass of expertise; iii) initiation of further collaborations, and iv) increased output and higher quality of publications in international peer-reviewed journals. UA 2007 ¿ ZAP-Startkredieten

Researcher(s)

• Promoter: Jordanova Albena

Research team(s)

• Neurogenetics Group

Project website

Project type(s)

• Research Project

Abstract

This project proposal aims to study the genetics of epilepsies in the population of European Romas (Gypsies). For this purpose the Neurogenetics group, Department of Molecular Genetics and the group of Prof. Luba Kalaydjieva, Center for Medical Research, Western Australian Institute for Medical Research will joint their patient collections, data and expertise to gain original knowledge of interst for the whole scientific community and for the society. Identification of loci and genes influencing susceptibility to epilepsy could facilitate early identification of individuals at risk and their adequate treatment.

Researcher(s)

• Promoter: Jordanova Albena
• Co-promoter: De Jonghe Peter

Research team(s)

• Neurogenetics Group
• VIB CMN - Molecular Neurogenomics

Project website

Project type(s)

• Research Project

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)

• Promoter: Timmerman Vincent
• Co-promoter: Jordanova Albena
• Fellow: Gonçalves Ricardo

Research team(s)

• Peripheral Neuropathies Group

Project type(s)

• Research Project

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.

Researcher(s)

• Promoter: Timmerman Vincent
• Co-promoter: Jordanova Albena

Research team(s)

• Peripheral Neuropathies Group

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Timmerman Vincent
• Co-promoter: Jordanova Albena
• Fellow: Gonçalves Ricardo

Research team(s)

• Peripheral Neuropathies Group

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Timmerman Vincent
• Co-promoter: Jordanova Albena

Research team(s)

• Peripheral Neuropathies Group

Project type(s)

• Research Project

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)

• Promoter: Jordanova Albena
• Co-promoter: De Jonghe Peter
• Co-promoter: Timmerman Vincent

Research team(s)

• Peripheral Neuropathies Group

Project type(s)

• Research Project

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)

• Promoter: Timmerman Vincent
• Co-promoter: De Jonghe Peter
• Fellow: Jordanova Albena

Research team(s)

• Peripheral Neuropathies Group

Project type(s)

• Research Project

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)

• Promoter: Van Broeckhoven Christine
• Co-promoter: De Jonghe Peter
• Co-promoter: Timmerman Vincent
• Fellow: Jordanova Albena

Research team(s)

Project type(s)

• Research Project

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)

• Promoter: Timmerman Vincent
• Fellow: Jordanova Albena

Research team(s)

Project type(s)

• Research Project