piRNA-34871调控线粒体功能在卵巢储备减退中的作用及机制研究

Premature ovarian aging (POA) is a condition where a woman’s ovaries don’t produce enough eggs and/or only eggs of bad quality relative to the woman’s age. In approximately 10 percent of women suffer from POA; however, the underlying molecular mechanisms of aging remain largely elusive. Many theories of aging have been proposed, including the free-radical and mitochondrial theories of aging. Both theories speculate that cumulative damage to mitochondria caused by reactive oxygen species (ROS) is one of the causes of aging. Piwi-interacting RNAs (piRNAs) are 26-31 nt small noncoding RNAs that are processed from their longer precursor transcripts by Piwi proteins. Localization of Piwi and piRNA has been reported mostly in nucleus and cytoplasm of higher eukaryotes germ-line cells, where it is believed that known piRNA sequences are located in repeat regions of nuclear genome in germ-line cells. However, localization of PIWI and piRNA in mitochondria and the role of mitochondria piRNA in POA yet remain unknown. Using small RNA-Sequence, we have identified specific piRNA from POA patients. Most target sequences of abnormal piRNAs located in mtDNA. Further support for the role of piR-34871 in follicle development, was provided by qRT-PCR, Norther Blot, transfection of in vitro cultured mouse ovary and TUNEL assay. The main purpose of the present study is to explore the role of piRNA in POA and mitochondria function. In this study, we will express or inhibit specific piRNA to investigate that 1) cell proliferation and apoptosis; 2) oxidative stress induced damage; 3) follicle development. These results will provide new insight into the properties of the piRNA and establish the hypothesis that piRNA-associated mitochondria damage is one possible cause of POA.

卵巢提早老化（Premature Ovarian Aging, POA）表现为月经周期正常女性卵巢储备功能降低，人群中约有9%的女性表现POA症状。目前病因尚不明确，氧化压力及其造成的线粒体损伤可能与之相关。本项目前期建立了POA患者卵泡颗粒细胞差异表达piRNA谱，发现并验证了piR-34871在POA患者中表达水平异常上调，体外小鼠卵巢组织培养中的研究发现piR-34871过表达可导致线粒体形态异常、促进细胞凋亡，减少原始和初级卵泡数，干扰卵泡发育。推测piR-34871可能通过影响线粒体功能参与卵巢储备调节。本项目拟通过分子及细胞生物学等手段，在细胞及卵巢组织中调整piR-34871的表达，结合施加氧化压力，分析细胞生长凋亡、线粒体功能、氧化压力耐受度及氧化损伤改变，验证piR-34871对卵泡发育的影响，研究piRNA调节卵巢储备功能的机制，为卵巢储备功能提早减退提供防治的新线索。