Multi-mtDNA Variants May Be a Factor Contributing to Mitochondrial Function Variety in the Skin-Derived Fibroblasts of Leber's Hereditary Optic Neuropathy Patients

Abstract

Heterogeneity is a major feature of Leber's hereditary optic neuropathy (LHON) and has a significant impact on the manifestation and diagnosis of the disease. This study explored whether multiple variations in mitochondrial genes were associated with the heterogeneity, mainly phenotypic heterogeneity. Ophthalmic examinations were conducted in two probands with LHON with G11778A and multiple mitochondrial DNA gene (mtDNA) variants. Skin fibroblast cell lines were generated from patients and age- and sex-matched controls. ROS levels, mitochondrial membrane potential, cell energy respiration, and metabolic functions were measured. Flow cytometry and cell viability tests were performed to evaluate the cell apoptosis levels and fate. We found that cells with more mtDNA variants had higher ROS levels, lower mitochondrial membrane potential, and weaker respiratory function. Flow cytometry and cell viability testing showed that multiple mtDNA variants are associated with different levels of cell viability and apoptosis. In conclusion, we found that skin-derived fibroblast cells from G11778A LHON patients could be used as models for LHON research. Multi-mtDNA variants contribute to mitochondrial function variety, which may be associated with heterogeneity in patients with LHON.

Superoxide dismutase 2 ameliorates mitochondrial dysfunction in skin fibroblasts of Leber’s hereditary optic neuropathy patients

“…Although fibroblasts cannot used for the study of axon degeneration and neural signaling, multiple studies demonstrated that they can be used as a valuable strategy for studying mitochondrial impairment in neurological disorders ( Olesen et al, 2022 ). In addition, our previous study ( Yao et al, 2022 ) and the current manuscript have proved that fibroblasts could reflect some cellular phenotypes of RGC cells with LHON, such as energy metabolism, mitochondrial dysfunction, and oxidative stress, which was consistent with iPSC. Therefore, in this study, we conducted LHON patients’ skin derived fibroblasts for the study of mitochondria function and inflammation.…”

Proteomic Profiling Reveals Increased Glycolysis, Decreased Oxidoreductase Activity and Fatty Acid Degradation in Skin Derived Fibroblasts from LHON Patients Bearing m.G11778A

“…Multiple studies indicated the derived fibroblasts as a valuable strategy for studying mitochondrial damage in neurological disorders, such as AD (Alzheimer’s Disease) [ 45 , 46 ], PD (Parkinson’s disease) [ 47 , 48 ], HD (Huntington’s disease) [ 49 , 50 ] and ALS (amyotrophic laternal sclerosis) [ 51 , 52 ]. Our previous studies also found mitochondrial dysfunction, respiration disorder and decreased cell viability in patients’ fibroblasts with m.G11778A [ 16 ]. Thus, to some extent, fibroblasts can stimulate the pathological process and can be used as an alternative model to explore molecular changes.…”

“…Finally, they were diagnosed as LHON bearing m.G11778A. Detailed information can be found in a previous article [ 16 ].…”

“…Although fibroblasts are not the primary affected tissues, their pathology changes may represent those in the sensitive cells, especially the mitochondrial function [ 15 ]. Our previous study also showed that LHON patient-derived skin fibroblasts (m.G11778A) presented mitochondrial dysfunction and could be used as a succedaneous cell model [ 16 ].…”

Pathogenicity and Function Analysis of Two Novel SLC4A11 Variants in Patients With Congenital Hereditary Endothelial Dystrophy

“…Finally, a PVDF membrane was exposed to enhanced chemiluminescence using a chemiluminescence apparatus (GelView6000Plus, Guangzhou Biolight Biotechnology, Guangzhou, China). 20 , 22 …”