Translating preclinical studies of mitochondrial disease mice towards monitoring disease progression in patients

点击翻译按钮获取中文摘要

Overall Aim: Establish a novel mice model of mitochondrial disease using patient specific variant MRPL44(L156R) and leverage multi-omics to build a comprehensive pathophysiology of mitochondrial disorders. Mitochondrial disorders are inherited multi-systemic genetic disorder with heterogeneous presentation. The mitochondria have their own separate protein synthesis mechanism which mitochondrial ribosomes (mitoribosomes) are part of. New emerging disease group of mitochondrial diseases are mutation in the mitoribosome; typically affecting production of proteins encoded by the mitochondrial DNA. Thus, a common biochemical deficiency found in patients of mitoribosome mutations are deficiency in the complexes of oxidative phosphorylation. MRPL44 is a protein of the large subunit and its variant L156R was found to be pathogenic originally in infantile cardiomyopathy patient. To date, there are 9 patients of MRPL44 mutations and all of the patients carry at least one allele of the L156R making it a key variant of interest. Additionally, there profound lack of robust animal models of mitochondrial disorders which is proving to be an hinderance in the development of therapeutics. Therefore, we want to first make a knock-in mice model using key patient specific variant MRPL44(L156R) that is accurately emulating patient phenotypes and then characterise the mice using multi-omics deep phenotyping looking at all the differences in the RNA, protein and metabolites. This will help to establish the mechanism of pathogenesis of mitochondrial disorders and find candidate biomarkers which is invaluable tool for monitoring the progression of disease which is particularly relevant in mitochondrial disorders. MethodsPhase one: validation of the MRPL44(L156R) mice as an accurate animal model of mitochondrial disorders. As the molecular phenotypes of the heart and liver were established already, we will demonstrate these molecular phenotypes in skeletal muscle and brain. The progressive nature of the disease will be validated using 4 different age groups: 1m, 3m, 6m and 12m. Phase two: deep phenotyping and characterisation of the MRPL44(L156R) mice using omics technology. RNA sequencing of a bigger cohort using different tissues will be performed. Moreover, Tandem-mass spectrometry will be performed on the key tissues in different age groups for proteomic and metabolomic analysis. This will be used to find candidate biomarkers. Phase three: the validation of biomarkers identified from the model in mitochondrial disease patient samples. This will require use of human tissues and will be done complying to the human tissue act. Ethical considerations: Although, this project uses mice as the subject of the primary investigation, this arm of the project does not require ethical approvals as the samples from the mice are already collected and there are no alive mice. This project will mainly consist of molecular analysis of mice tissues. Cell lines are not covered by human tissue act.