HIP调控人胎儿胰腺前体细胞向胰岛细胞分化的机制及其移植应用

Human fetal pancreatic progenitor cells (hFPPCs) could differentiated into islet-like clusters by in-vitro induction, which opened another door to resolve the shortage of donor organs for islet transplantation in the diabetic treatment. However, the efficiency of differentiation of human pancreatic progenitor cells is deficient and the transplantation of the hFPPCs-derived islet-like clusters is not satisfying. Here, we found that Human pro-islet peptide (HIP) could improve the differentiation of hFPPCs. With HIP treatment, the expression of β cell related maker genes significantly increased. In this study, we will determine the definitive pathway in which HIP promotes the differentiation of hFPPCs in vitro. In addition, we will find out the epigenetic mechanism by which HIP regulate the β cell related transcription factors. To evaluate the function of HIP treated islet-like clusters, we will transplant them into diabetic nude mice and detect the serum glucose level, insulin secretion and the morphology of the transplanted structures. Our results will be helpful to understand the molecular mechanism of HIP-regulated hFPPCs in vitro differentiation and optimize the induction methods for more effective transplantation.

人胎儿胰腺前体细胞(hFPPCs)经体外诱导分化为类胰岛细胞，为胰岛移植治疗糖尿病所面临的供体严重不足以及免疫排斥等问题提供了新的解决办法。但是其体外诱导分化效率低，时间长，移植之后对糖尿病的治疗效果有限。我们发现人胰岛新生多肽（HIP）能够显著促进hFPPCs的体外诱导分化，添加HIP处理之后，hFPPCs中与β细胞分化相关的转录因子的基因表达水平均显著上调。本项目拟明确HIP调控hFPPCs体外诱导分化的下游通路，深入探讨HIP在该过程中对β细胞分化相关转录因子的表观遗传学调控，最终借助体内移植实验从胰岛素分泌，血糖水平，移植物组织化学分析三个方面探讨HIP处理的hFPPCs经体外诱导分化并移植后，对STZ诱导的糖尿病裸鼠的治疗效果。这将有助于深入揭示HIP参与调控hFPPCs体外诱导分化的分子机制，提高其体外诱导分化效率，优化移植效果，为胰岛细胞移植治疗糖尿病提供新的思路。

在项目资助下，我们阐明了胰岛新生多肽（HIP）促进人胎儿胰腺前体细胞(hFPPCs)分化的作用机制，发现了HIP介导的信号通路与调控胰岛发育分化的FoxO1/menin通路之间的联系。首先，HIP可以促进与胰岛形成相关的转录因子PDX-1，MAFA 和NKX6.1的转录，显著增加分化细胞的胰岛素含量，将HIP处理的分化细胞移植入糖尿病裸鼠模型中，其表现出更强的降糖能力。深入研究发现，HIP通过激活AKT的磷酸化下调了FoxO1的蛋白水平，导致menin蛋白的下调，从而减少menin在胰岛形成相关转录因子的启动子区域的结合，不能招募H3K9甲基转移酶SUV39H1，引起H3K9me3标记减少。随着抑制性H3K9me3标记的减少，启动子激活，PDX-1，MAFA 和NKX6.1转录增强，最终促进了胎儿胰腺前体细胞的体外分化。这些研究结果强烈表明了HIP作为体外诱导的添加剂，促进hFPPCs在体外分化成有功能的β细胞并用于人类糖尿病患者胰岛移植治疗的巨大潜力。