Epigenetic control of spermatogonial stem cell self-renewal

项目摘要 在精原干细胞更新的推动下，男性在成年期间不断地产生精子 (SSCS)。这项申请的长期目标是确定一种新的表观遗传学计划的作用，该计划 我们最近发现，在调节成年SSCs的更新方面。SSCS既可以自我更新，也可以生产 将分化以启动精子发生的前体精原细胞。平衡SSC自我和 更新和分化是成年男性终生生产精子的关键。干细胞移植和 在体外，SSC培养使SSC的功能研究成为可能，并允许促进翻译 在动物转基因中的应用。然而，尽管人们对精子发生有很多了解，但对精子发生的调控 SSC的自我更新仍然鲜为人知。干细胞更新既需要干细胞内在因素，也需要 外部生态位因素，只有少数几个已被确定(PLZF、RB、NANOS2、GDNF、ETV5等)。 值得注意的是，它们在SSC自我更新中的作用已经通过遗传学研究得到了揭示。尽管如此 随着研究的进展，对SSC的分子生物学控制仍然知之甚少。我们已经确定了一个 表观遗传因子DOT1L，唯一的H3K79甲基转移酶，作为小鼠SSC自我调节的新的主调控因子 更新。此外，通过化学抑制DOT1L，我们能够识别可能 为续签SSC做出贡献。我们提出了一种创新的多管齐下的(遗传、化学、基因组和 蛋白质组学)的方法，全面阐明这一新的表观遗传程序在SSCs。AS在SSC中出现故障 自我更新导致精子生成不足，从而导致男性不育，该项目的完成将为 为干细胞更新的分子解剖奠定坚实的基础，开辟干细胞研究的新途径 生物学和生殖医学。

Project Summary Males produce sperm continuously through adult life, driven by the renewal of spermatogonial stem cells (SSCs). The long-term objective of this application is to determine the role of a novel epigenetic program that we have recently identified in regulating the renewal of adult SSCs. SSCs can both self-renew and produce progenitor spermatogonia that will differentiate to initiate spermatogenesis. The balance between SSC self- renewal and differentiation is key for life-long production of sperm in adult males. Both SSC transplantation and in vitro SSC cultures have enabled functional studies of SSC and allowed for advancement of translational applications in animal transgenesis. However, while much is known about spermatogenesis, the regulation of SSC self-renewal remains poorly understood. Stem cell renewal requires both stem cell-intrinsic factors and external niche factors, only a handful of which have been identified (PLZF, RB, NANOS2, GDNF, ETV5, etc.). Notably, their functions in SSC self-renewal have been revealed through genetic studies. Despite these advances, the molecular biological control of SSC remains poorly understood. We have identified an epigenetic factor DOT1L, the sole H3K79 methyltransferase, as a novel master regulator of mouse SSC self- renewal. Moreover, by chemically inhibiting DOT1L, we were able to identify specific target genes that likely contribute to SSC renewal. We propose an innovative multi-pronged (genetic, chemical, genomic, and proteomic) approach to comprehensively elucidate this novel epigenetic program in SSCs. As failure in SSC self-renewal leads to a lack of sperm production and thus male infertility, completion of this project will lay a firm foundation for molecular dissection of SSC stem cell renewal and open new avenues of research in SSC biology and reproductive medicine.