Abstract：
Reprogramming of somatic cells into a pluripotent state is known to be accompanied by extensive restructuring of mitochondria and switch in metabolic requirements. Here we utilized Leber\'s hereditary optic neuropathy (LHON) as a mitochondrial disease model to study the effects of homoplasmic mtDNA mutations and subsequent oxidative phosphorylation (OXPHOS) defects in reprogramming. We obtained fibroblasts from a total of 6 LHON patients and control subjects, and showed a significant defect in complex I respiration in LHON fibroblasts by high-resolution respiratory analysis. Using episomal vector reprogramming, our results indicated that human induced pluripotent stem cell (hiPSC) generation is feasible in LHON fibroblasts. In particular, LHON-specific OXPHOS defects in fibroblasts only caused a mild reduction and did not significantly affect reprogramming efficiency, suggesting that hiPSC reprogramming can tolerate a certain degree of OXPHOS defects. Our results highlighted the induction of genes involved in mitochondrial biogenesis (TFAM, NRF1), mitochondrial fusion (MFN1, MFN2) and glycine production (GCAT) during reprogramming. However, LHON-associated OXPHOS defects did not alter the kinetics or expression levels of these genes during reprogramming. Together, our study provides new insights into the effects of mtDNA mutation and OXPHOS defects in reprogramming and genes associated with various aspects of mitochondrial biology.
摘要：
已知将体细胞重编程为多能状态伴随着线粒体的广泛重组和代谢需求的转变。在这里，我们利用Leber的遗传性视神经病变（LHON）作为线粒体疾病模型来研究同质mtDNA突变和随后的氧化磷酸化（OXPHOS）缺陷在重编程中的影响。我们从总共6名LHON患者和对照受试者中获得成纤维细胞，并通过高分辨率呼吸分析显示LHON成纤维细胞的复杂I呼吸存在明显缺陷。使用附加型载体重编程，我们的结果表明，人诱导多能干细胞（hiPSC）在LHON成纤维细胞中的产生是可行的。特别是,成纤维细胞中的LHON特异性OXPHOS缺陷仅引起轻度减少，并没有显着影响重编程效率，表明hiPSC重编程可以容忍一定程度的OXPHOS缺陷。我们的结果强调了参与线粒体生物发生的基因的诱导(TFAM，NRF1),重编程过程中的线粒体融合（MFN1，MFN2）和甘氨酸产生（GCAT）。然而,LHON相关的OXPHOS缺陷在重编程过程中不会改变这些基因的动力学或表达水平。一起,我们的研究为mtDNA突变和OXPHOS缺陷在重编程和与线粒体生物学各个方面相关的基因中的影响提供了新的见解.
