端粒由DNA重复序列（TTAGGG)n及相关蛋白组成,位于染色体末端维持染色体稳定性。端粒随着细胞增殖、分化或年龄增长而缩短。端粒缩短及其功能紊乱会影响生殖细胞、颗粒细胞及微环境，可导致卵巢衰老及不孕不育。在本项目申请中，我们期望验证这样一个假设：通过多能干细胞技术可以使卵子及颗粒细胞的端粒得到再生，从而有效用于卵巢功能重建。并进一步探究端粒变短影响生殖细胞及前体颗粒细胞分化、引起卵巢早衰及不育的分子机制。我们以小鼠作为实验模型，提出了三个主要研究内容：1）卵子端粒再生用于卵巢功能重建；2）颗粒细胞端粒再生用于卵巢功能重建；3）通过修复端粒酶基因使端粒和卵巢功能恢复。最终，我们期望通过重建卵巢功能，恢复自然衰老小鼠、化疗小鼠及端粒酶敲除小鼠的生殖和内分泌功能。本项目在小鼠模型研究中获得成果，期望会对人类卵巢功能重建及卵巢衰老机制提供新的认识和有重要意义的前期基础。

Telomeres are composed of repeated DNA sequences (TTAGGG)n and associated proteins located at the chromosome ends, and maintain chromosomal stability. Telomeres shorten with age, in general, and particularly dysfunction of ovaries including their germ cells, follicular granulosa cells and niches occurs with age and these compartments also show telomere shortening and dysfunction. We previously showed that telomere shortening causes infertility and premature ovarian aging using telomerase knockout mouse model. In this proposal, we intend to test the hypothesis that telomeres can be rejuvenated in germ cells and granulosa cells （pre-granulosa cells）by pluripotent stem cell technology and that telomere-rejuvenated germ cells and granulosa cells （pre-granulosa cells）can be used for reconstruction of functional ovaries. We also will investigate the mechanisms underlying the negative impacts of short telomeres on differentiation of germ cells and granulosa cells (pre-granulosa cells), causing infertility and premature ovarian aging. To achieve these goals, we propose three main research areas of studies: 1) Telomere rejuvenation by creating pluripotent stem cells from oocytes for differentiation to germ cells and granulosa cells (pre-granulosa cells) to reconstruct ovarian function; 2) Telomere rejuvenation by creating pluripotent stem cells from granulosa cells (pre-granulosa cells) for differentiation to germ cells and granulosa cells（pre-granulosa cells）to reconstruct ovarian function; 3) Telomere rejuvenation and reconstruction of ovarian function in ovarian premature aging mouse model using telomerase knockout mice. Eventually, we aim at reconstituting artificial ovaries for recover of ovarian functions using different mouse models including natural ovarian aging mice, chemo-treated mice, and telomerace knockout mice with premature ovarian aging. If proven to be successful in mouse models, this will be significant for combating natural ovarian aging in women, and for improving reproductive life span of chemo-therapy and premature ovarian aging patients.