Epigenetic Regulation by FoxO1 in Pancreatic Beta Cells

项目摘要 在过去的30年里，糖尿病已经成为一种流行病。2型糖尿病是最常见的一种 糖尿病和胰腺β细胞衰竭在这种代谢紊乱的发病机制中起关键作用。恢复β信元 通过诱导β细胞，其功能在开发治疗糖尿病的方法中占据了中心地位 增殖、再分化和再生。然而，β细胞的质量和数量都较少 比理想要好得多。促进这些过程以产生“完美的”β细胞的一个关键方面是理解 表观遗传学变化参与β细胞的形成和维持。越来越多的证据表明 组蛋白修饰和染色质重塑在β细胞发育、细胞命运决定、 增殖和再生。关键的β细胞转录因子FOXO1是维持β细胞成熟度所必需的。 去除β细胞中的FoxO1会导致β细胞去分化，这是一个成熟的β细胞失去身份的过程 以及制造和分泌胰岛素的能力。在健康的β细胞中，FOXO1是不活跃的，存在于细胞质中。在……里面 对应激源的反应，如衰老和多胎，FoxO1移位到细胞核中，并引发 转录网络保护β细胞健康。在晚期2型糖尿病中，FoxO1从β细胞中消失 由于降解增加，导致代谢缺乏灵活性，并为去分化铺平道路。 然而，FOXO1对β细胞失败的保护作用是否涉及维持表观基因组 景观尚未被研究过。拟议的研究将填补FoxO1和FoxO1之间的知识空白， 表观遗传学、功能基因组学和糖尿病。PI提供了初步数据来确定FoxO1的作用 在带有RNAseq和组蛋白修饰ChIPseq的表观遗传学中(即，H3K4me3、H3K27me3和H3K27ac) 用FAC分选β细胞特异性FoxO1KO小鼠的β细胞。PI将继续建设一体化的 胰腺β细胞FoxO1高C、甲基化和FoxO1ChIPseq的调控图谱。H3K27ac主题 分析和核糖核酸图谱表明FOXO1和HNF4α之间存在不平衡的调节，因此，PI将 进行葡萄糖钳夹试验、葡萄糖耐量试验、葡萄糖和精氨酸刺激的胰岛素分泌 β细胞特异性FoxO_1和HnF_4α双KO小鼠，以确定其上位性。 Foxo1和HNF4α。PI还将从功能上表征FoxO1靶标，以识别治疗性基因 利息。量身定做的研究培训和职业发展活动将帮助PI实现其职业生涯 目标：成为一名独立的学术研究者，推动糖尿病研究领域的发展。

Project Summary Over the last 30 years, diabetes has become a pandemic. Type 2 diabetes is the most common form of diabetes, and pancreatic β cell failure is pivotal in the pathogenesis of this metabolic disorder. Restoring β cell function has taken center stage in developing therapeutics to “cure” diabetes, through inducing β cell proliferation, re-differentiation, and regeneration. However, the quality and quantity of “β cell” obtained are less than ideal. One critical aspect to facilitate these processes to generating “perfect” β cell is to understand the epigenetic changes involved in β cell formation and maintenance. More and more evidence suggests that histone modification and chromatin remodeling play critical roles in β cell development, cell fate commitment, proliferation, and regeneration. Key β cell transcription factor FoxO1 is required to maintain β cell maturity. Ablation of FoxO1 in β cells leads to β cell dedifferentiation, a process where mature β cells lose their identity and ability to produce and secret insulin. In healthy β cells, FoxO1 is inactive and resides in the cytoplasm. In response to stressors, such as aging and multiparity, FoxO1 translocates into the nucleus, and elicits transcriptional networks to defend β cell health. In advanced type 2 diabetes, FoxO1 disappears from β cells as a result of increased degradation, leading to metabolic inflexibility and paving the way for dedifferentiation. However, whether the protective role of FoxO1 against β cell failure involves maintaining the epigenomic landscape has not been studied. The proposed studies will fill the gap of knowledge between FoxO1, epigenetics, functional genomics, and diabetes. The PI presented preliminary data to establish a role of FoxO1 in epigenetics with RNAseq and histone modification ChIPseq (i.e., H3K4me3, H3K27me3, and H3K27ac) using FAC sorted β cells in β cell-specific FoxO1 KO mice. The PI will continue to build the integrative regulatory map of FoxO1 in pancreatic β-cell with Hi-C, DNA methylation, and FoxO1 ChIPseq. H3K27ac motif analysis and RNA profiling suggest an imbalanced regulation between FoxO1 and Hnf4α, therefore, the PI will perform glucose clamps, glucose tolerance test, glucose- and arginine-stimulated insulin secretion in isolated islets, and RNAseq using β cell-specific FoxO1 and Hnf4α double KO mice to determine the epistasis of FoxO1 and Hnf4α. The PI will also functionally characterize FoxO1 targets to identify genes of therapeutic interest. The tailored research training and career development activities will assist the PI to achieve her career goals: becoming an independent academic investigator and advancing the field of diabetes research.