FTO在调节人干细胞稳态和衰老中的作用

Stem cell exhaustion and epigenetic alterations play important roles in aging. Fat mass and obesity-associated gene (FTO), an N6-methyladenosine (m6A) RNA demethylase, is implicated in adipogenesis, neurogenesis and tumorigenesis via affecting m6A levels and thereby changing mRNA fate. However, the functions of FTO in maintaining human stem cell homeostasis and senescence have remained unclear. To study this, we generated FTO-deficient human embryonic stem cells (hESCs) using CRISPR/Cas9 technique. Depletion of FTO did not affect the pluripotency and self-renewal capability in hESCs. FTO-deficient human mesenchymal stem cells (hMSCs) was obtained via directed differentiation and exhibited delayed proliferation rate and premature senescence. In addition, we also have established directed differentiation systems to neural stem cells (hNSCs) and endothelial cells (hECs) from hESCs. In future, we plan to obtain FTO-deficient hNSCs and hECs and investigate regulatory roles of FTO in homeostasis maintenance of hNSCs and hECs. Further, to study the underlying molecular mechanisms, Immunoprecipitation–Mass Spectrometry (IP-MS), RNA-Seq and meRIP-seq will be performed to identify FTO new interacting partners, and to investigate the global m6A levels and m6A targets during stem cell senescence. Therefore, we aim to study the roles of post-transcriptional RNA modification in maintaining stem cell homeostasis and aging and try to provide potential therapeutic strategies to rejuvenate senescence and aging-related disease.

干细胞耗竭和表观遗传学的改变是导致衰老的重要因素。脂肪及肥胖症相关蛋白FTO作为m6A修饰的去甲基化酶，通过改变m6A水平从而影响mRNA命运，参与脂肪代谢、神经发育和癌症发生。但FTO在人干细胞稳态和衰老中作用还不清楚。我们利用CRISPR/Cas9技术在人胚胎干细胞中将FTO敲除，FTO的缺失并不影响人胚胎干细胞的多能性。将敲除FTO的人胚胎干细胞定向分化成人间充质干细胞，发现FTO的缺失会加速人间充质干细胞的细胞衰老。同时我们已经建立和完善了人胚胎干细胞向神经干细胞和终末分化的内皮细胞的分化体系。之后我们将进一步分化获得FTO缺失的神经干细胞等人成体干细胞以及终末分化的内皮细胞，探索FTO在干细胞稳态和衰老的作用。最后通过免疫沉淀质谱分析、RNA-Seq和meRIP-seq等技术探索RNA修饰在干细胞稳态和衰老的分子机制和靶标，寻找延缓衰老和治疗衰老相关疾病的可能干预手段。

干细胞耗竭和表观遗传学的改变是导致衰老的重要因素。脂肪及肥胖症相关蛋白FTO作为m 6A修饰的去甲基化酶，通过改变m6A水平从而影响mRNA命运，参与脂肪代谢、神经发育和癌症发生。但FTO在人干细胞稳态和衰老中作用还不清楚。首先利用CRISPR/Cas9技术在人胚胎干细胞中将FTO敲除，FTO的缺失并不影响人胚胎干细胞的多能性和自我更新能力。将敲除FTO的人胚胎干细胞定向分化成人间充质干细胞，发现FTO的缺失会加速人间充质干细胞的细胞衰老。机制上，我们发现FTO通过m6A非依赖的方式调控MIS12（一种动力蛋白，参与细胞周期调控）的稳定性从而调控细胞衰老进程。综上所述，我们的研究阐述m6A修饰蛋白调节干细胞稳态和衰老的机制，寻找延缓衰老和治疗衰老相关疾病的可能干预靶标。

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