MITOBIOPATH · DISCOVERING NEW DISEASE PATHWAYS AFFECTING mtDNA METABOLISM
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2016-05-01 → 2018-04-30
- EU contribution
- €195,455
- Participants
- 2
- Scheme
- MSCA-IF-EF-RI
Lines connect the coordinator with its partners.
Results in brief
DISCOVERING NEW DISEASE PATHWAYS AFFECTING mtDNA METABOLISM
Mitochondrial disorders are a group of genetically and clinically heterogeneous conditions that have emerged as the most common cause of metabolic disease in children and adults with a minimum estimated prevalence of 1/5000 live birth. Defects in mitochondrial DNA (mtDNA) metabolism (replication and translation) cause a substantial fraction of mitochondrial disorders, characterized by combined defective activities of mtDNA-dependent respiratory chain complexes. Genetically, they are Mendelian inherited as autosomal dominant, recessive or X-linked trait. Clinically, defect in mtDNA metabolism present as a spectrum of disorders ranging from: a) severe infantile multi-systemic disease, rapidly progressing to exitus; b) to childhood myopathy slowly progressing to severe motor dysfunction in adult age; c) or tissue-specific disorders manifesting at any age of life. The clinical and molecular genetics variability challenges the diagnosis and 60% of patients still lack of molecular diagnosis. In MITOBIOPATH project I aimed to discover new mitochondrial disease genes and proteins, and to elucidate new disease-associated metabolic pathways, which are key steps toward the development of treatment strategies. I achieved these major goals by applying whole exome sequencing (Work package 1) to DNA samples from a cohort of patients with suspected mitochondrial disorders and multiple OXPHOS defect and by studying the pathomechanism in in vitro models (Work package 2). Other than a primary role in genetically inherited mitochondrial disorders, proteins operating the control of the mtDNA metabolism are involved in the mechanism of genetic or aging-related neurodegenerative disorders. Therefore, in the work package 3, I have focused my research activity on Fbxl4 protein that, based on preliminary studies on patients’ fibroblasts, has been hypothesized playing role in mtDNA biogenesis and mitochondrial network organization. The overall project led to the discovery of new disease-causing genes for complex mitochondrial disorders, to the identification of new pathways involving proteins whose main function is outside of mitochondria (cytoskeleton or cytoplasm) and to the definition of new phenotypes and/or additional function for known mitochondrial proteins. Advances on Fbxl4 protein function were also made who resulted to be essential for life in the KO mouse model.
Data: CORDIS, © European Union
Project objective
Defects of mitochondrial DNA (mtDNA) metabolism (maintenance, integrity and expression) are the most common cause of multiple mitochondrial respiratory chain (MRC) defects in children. Several new disease genes have been identified in these complex pathways but the functional link between mutant protein and mtDNA metabolism is unknown or poorly understood. Example of the latter is FBXL4 (F-box and leucine-rich repeat protein 4) gene, mutations of which have been recently found in 28 patients with a multisystem complex syndrome, hallmarked by combined MRC defect and reduction of mtDNA copy number in muscle and fibroblasts. Approximately 60% of patients still lack genetic definition of their disease. Objective of MITOBIOPATH proposal is the discovery and characterization of novel mitochondrial biogenetic and maintenance pathways by implementing three specific aims. 1) Gene discovering by whole exome sequencing (WES): unbiased WES screening will be applied to a large cohort of paediatric patients presenting early onset hypotonia, developmental delay, failure to thrive, severe encephalomyopathy and/or liver failure associated with combined MRC defects. 2) Pathogenic pathways revealed by new gene defects: functional studies using cellular and animal models (knock-out zebrafish or mouse models) will be performed to establish the pathogenic mechanism of the mutation(s) and the function of unknown disease-associated protein(s); 3) FBXL4 function in cellular and in vivo models: immortalized cell lines expressing six different FBXL4 mutations will be generated by using CRISP/Cas9 technology and characterized with a combined molecular, biochemical and proteomic approaches. In addition, proteins in the Parkin-proteasome complex were recently identified as potential partners of FBXl4, and they will be further analyzed. Knock-out mouse model of Fbxl4 will be also investigated. Overall results will have impact on both mitochondrial disorders and other neurodegenerative disease.
Original text from CORDIS.
Participants
- THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE · CAMBRIDGECoordinatorUnited Kingdom
- UNITED KINGDOM RESEARCH AND INNOVATION · SWINDONUnited Kingdom
Links
Data: CORDIS, © European Union