非线粒体定位Sirtuins在人类干细胞稳态和衰老中的作用及机制研究

Aging populations is becoming a tough challenge faced by China. Stem cell homeostasis maintenance may retard aging, which provides new thoughts to meet this challenge. The sirtuins family is a class of proteins closely related to lifespan extension. The non-mitochondrial sirtuins encoded in humans include SIRT1, SIRT2, SIRT6 and SIRT7. Preliminary studies indicate that SIRT6 maintains the balance of human mesenchymal stem cells by regulating redox homeostasis, however, the regulatory mechanism of SIRT1/2/7 related to human stem cell homeostasis and the role of SIRT6 in homeostasis maintenance in other types of stem cells remain unclear. Besides, it is unknown what is the difference or connection of functions between the non-mitochondrial sirtuins. In this project, we will generate isogenic non-mitochondrial sirtuins-null human embryonic stem cells (SIRT1/2/6/7 knockout hESCs) via the CRISPR/Cas9 mediated gene editing technique, and further differentiate them into adult stem cells and terminally differentiated cells. With the combination of phenotype and multi-omics analyses, we expect to systematically elucidate the non-mitochondrial sirtuins regulatory mechanism in the homeostasis and aging of human pluripotent stem cells. This project would contribute to a better understanding of the mechanism of human adult stem cell aging, and provide a theoretical basis for aging interventions.

如何科学应对衰老及相关疾病带来的社会压力是我国正在面临的严峻挑战。维持干细胞的稳态可以一定程度上延缓个体衰老，为应对这一挑战提供了思路。Sirtuins家族是一类与个体寿命延长密切相关的蛋白，人类编码的非线粒体定位Sirtuins包括SIRT1/2/6/7。初步研究表明SIRT6通过调节氧化还原稳态维持了人间充质干细胞平衡，但SIRT1/2/7与人类干细胞稳态相关的调节机制以及SIRT6在其它类型干细胞稳态维持中的作用尚不明确，并且缺乏SIRT1/2/6/7之间功能的比较。本项目拟通过利用CRISPR/Cas9介导的基因编辑技术分别产生SIRT1/2/6/7基因敲除的人胚胎干细胞系，并将其进一步分化为成体干细胞和终末分化细胞，结合生物学表型和多组学联合分析，系统阐明非线粒体定位的Sirtuins在人多能干细胞稳态维持及衰老中的作用和分子机制，为认识人类干细胞衰老和有效干预衰老提供理论依据。

伴随着全球老龄化程度的日益加深，人口老龄化及衰老相关疾病高发已成为中国乃至世界面临的重大社会和科学问题。干细胞耗竭是衰老的主要标志之一，寻找干细胞耗竭的关键靶点对于实现衰老相关疾病的预警和干预、实现健康老龄化具有重要的研究意义。Sirtuins家族是一个著名的长寿基因家族，是一类进化保守的NAD+依赖的去乙酰化酶，在诸多生物学过程中发挥着重要的调控作用。研究表明非线粒体定位的Sirtuins与衰老过程密切相关，但其在人成体干细胞的稳态调控中功能的区别与联系仍有待进一步研究。本研究基于CRISPR/Cas9介导的基因组靶向编辑技术，构建了非线粒体定位的Sirtuins——SIRT1、SIRT2、SIRT6和SIRT7缺失的人胚胎干细胞。通过定向分化获得了SIRT1、SIRT2、SIRT6和SIRT7缺失的人间充质干细胞，发现其出现多种衰老表型。进一步对其转录组、组蛋白修饰、DNA甲基化修饰进行全基因组范围解析，旨在揭示非线粒体定位Sirtuins在人成体干细胞稳态维持中的作用机制，绘制其与靶基因和互作蛋白的分子调控网络，从而为干预衰老提供理论依据和潜在的分子靶标。