Xiaofen Jin1,2,3, Juanjuan Zhang4, Qiuzi Yi2,3, Feilong Meng2,3, Jialing Yu1,2,3, Yanchun Ji2,3, Jun Q Mo5, Yi Tong4, Pingping Jiang2,3, Min-Xin Guan1,2,3,6,7. 1. Key Laboratory of Reproductive Genetics, Ministry of Education of PRC, The Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. 2. Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. 3. Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, and National Clinic Research Center for Child Health, Hangzhou, Zhejiang, China. 4. School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China. 5. Department of Pathology, Rady Children's Hospital, University of California School of Medicine, San Diego, California, United States. 6. Zhejiang Provincial Key Laboratory of Genetic and Developmental Disorders, Hangzhou, Zhejiang, China. 7. Zhejiang University-University of Toronto Joint Institute of Genetics and Genome Medicine, Hangzhou, Zhejiang, China.
Abstract
Purpose: To investigate the mechanism underlying the synergic interaction between Leber's hereditary optic neuropathy (LHON)-associated ND1 and mitochondrial tyrosyl-tRNA synthetase (YARS2) mutations. Methods: Molecular dynamics simulation and differential scanning fluorimetry were used to evaluate the structure and stability of proteins. The impact of ND1 3635G>A and YARS2 p.G191V mutations on the oxidative phosphorylation machinery was evaluated using blue native gel electrophoresis and enzymatic activities assays. Assessment of reactive oxygen species (ROS) production in cell lines was performed by flow cytometry with MitoSOX Red reagent. Analysis of effect of mutations on autophagy was undertaken via flow cytometry for autophagic flux. Results: Members of one Chinese family bearing both the YARS2 p.191Gly>Val and m.3635G>A mutations exhibited much higher penetrance of optic neuropathy than those pedigrees carrying only the m.3635G>A mutation. The m.3635G>A (p.Ser110Asn) mutation altered the ND1 structure and function, whereas the p.191Gly>Val mutation affected the stability of YARS2. Lymphoblastoid cell lines harboring both m.3635G>A and p.191Gly>Val mutations revealed more reductions in the levels of mitochondrion-encoding ND1 and CO2 than cells bearing only the m.3635G>A mutation. Strikingly, both m.3635G>A and p.191Gly>Val mutations exhibited decreases in the nucleus-encoding subunits of complex I and IV. These deficiencies manifested greater defects in the stability and activities of complex I and complex IV and overproduction of ROS and promoted greater autophagy in cell lines harboring both m.3635G>A and p.191Gly>Val mutations compared with cells bearing only the m.3635G>A mutation. Conclusions: Our findings provide new insights into the pathophysiology of LHON arising from the synergy between ND1 3635G>A mutation and mitochondrial YARS2 mutations.
Purpose: To investigate the mechanism underlying the synergic interaction between Leber's hereditary optic neuropathy (LHON)-associated ND1 and mitochondrial tyrosyl-tRNA synthetase (YARS2) mutations. Methods: Molecular dynamics simulation and differential scanning fluorimetry were used to evaluate the structure and stability of proteins. The impact of ND1 3635G>A and YARS2p.G191V mutations on the oxidative phosphorylation machinery was evaluated using blue native gel electrophoresis and enzymatic activities assays. Assessment of reactive oxygen species (ROS) production in cell lines was performed by flow cytometry with MitoSOX Red reagent. Analysis of effect of mutations on autophagy was undertaken via flow cytometry for autophagic flux. Results: Members of one Chinese family bearing both the YARS2 p.191Gly>Val and m.3635G>A mutations exhibited much higher penetrance of optic neuropathy than those pedigrees carrying only the m.3635G>A mutation. The m.3635G>A (p.Ser110Asn) mutation altered the ND1 structure and function, whereas the p.191Gly>Val mutation affected the stability of YARS2. Lymphoblastoid cell lines harboring both m.3635G>A and p.191Gly>Val mutations revealed more reductions in the levels of mitochondrion-encoding ND1 and CO2 than cells bearing only the m.3635G>A mutation. Strikingly, both m.3635G>A and p.191Gly>Val mutations exhibited decreases in the nucleus-encoding subunits of complex I and IV. These deficiencies manifested greater defects in the stability and activities of complex I and complex IV and overproduction of ROS and promoted greater autophagy in cell lines harboring both m.3635G>A and p.191Gly>Val mutations compared with cells bearing only the m.3635G>A mutation. Conclusions: Our findings provide new insights into the pathophysiology of LHON arising from the synergy between ND1 3635G>A mutation and mitochondrial YARS2 mutations.