线粒体基因组不稳定影响hiPSC分化及线粒体糖尿病发生的研究

Mitochondrial genomic stability is essential for the function of mitochondrial, cell respiration and metabolism. Once the mitochondrial genomic stability is compromised, a series of mitochondrial dysfunction and diseases including mitochondrial diabetes would occur. One mitochondrial DNA polymerase, DNA polymerase gamma (polγ) is responsible for maintaining mitochondrial genomic stability. A specific mutation of polγ(D257A) leads to mitochondrial dysfunction during embryonic development and mitochondrial diabetes in mice. However, whether the two events are molecularly correlated is still unclear. Here we seek to use human induced pluripotent stem cells (hiPSC) to address this question. Using genomic knock-in mediated by homologous recombination, we established hiPSC cell models bearing the human polγ(D274A) mutation which is conserved with polγ(D257A) in mice. The mitochondrial genome sequencing is also carried on in order to find mutations that may be responsible for defects in embryonic development and for mitochondrial diabetes. We will further study two related questions: 1) How would mitochondrial genomic mutations alter cell respiration and metabolism during hiPSC differentiation? 2) Whether the pathogenesis of mitochondrial diabetes is the consequence of mitochondrial mutations mediated defects in cell respiration. Understanding these mechanisms would provide new insight into how the genomic stability of mitochondrial plays roles in the development of mitochondrial diabetes.

线粒体基因组稳定性是线粒体活性和细胞呼吸代谢的重要保证。破坏其基因组稳定性会导致细胞呼吸代谢紊乱并引发代谢疾病。小鼠线粒体DNA 聚合酶γ(polγ)复制校正功能活性突变引起胚胎发育缺陷的同时也导致小鼠线粒体糖尿病的发生，但两者的内在联系和分子机制尚不清楚。为了阐明此问题，我们在人诱导多能干细胞(hiPSC)导入与小鼠保守的人polγ突变形式polγD274A，模拟线粒体糖尿病状态，深入研究线粒体基因组不稳定如何影响hiPSC分化过程中线粒体功能和呼吸代谢方式的转变。我们前期研究已成功构建含polγD274A突变的 hiPSC并正在进行线粒体基因组测序。将以此为基础重点研究两个相互关联的内容：1)hiPSC分化过程中polγD274A导致线粒体基因组不稳定对细胞呼吸代谢方式转换的影响2)线粒体基因组不稳定对呼吸代谢的影响是否是线粒体糖尿病发生的主要因素，为线粒体糖尿病基因治疗提供理论支持。