Identifying Physiological and Molecular Inducers of Beta Cell Maturation

项目摘要 糖尿病是一种血糖调节紊乱的疾病，在中国有超过8%的人受到影响 美国。在糖尿病患者中，胰岛分泌胰岛素的β细胞不能正常 因胰岛细胞数量不足或胰岛细胞不足而维持正常血糖水平 功能。通过替换胰岛治疗糖尿病已经被提出作为一种治疗策略，但可以移植。 材料是有限的。了解如何从替代来源生产具有功能的贝塔细胞可以绕过 这一限制使胰岛替代疗法成为可能。目前β细胞体外培养方法的研究进展 产生表达胰岛素的细胞，但类似于胎儿或新生儿的β细胞，但对葡萄糖的调节有限 容量。这个项目将研究生理和分子信号通常诱导胰岛 从不成熟、功能较差的状态转变为能够有效血糖的成熟细胞类型 监管。为了实现这一点，我们将首先测试模拟正常葡萄糖诱导的细胞去极化是否通过 在培养的胰岛实验中诱导预定的电活动足以将未成熟的出生后 转化为成熟的、功能齐全的β细胞。电活动将通过表达来控制 光遗传蛋白，特别是在β细胞中，这将产生穿过细胞膜的电流 当细胞暴露在特定波长的光中时。第二，我们将测试是否激活 钙调神经磷酸酶/NFAT信号通路，它感知细胞的钙水平并正常控制β细胞 增殖和功能，足以促进培养的未成熟胰岛的成熟。这些研究将 揭示控制胰岛在发育过程中正常获得功能的细胞和分子刺激，以及 将为从可再生资源中产生新的功能贝塔细胞的努力提供信息。

Project Summary Diabetes mellitus is a disease of disordered regulation of blood sugar, affecting over eight percent of people in the United States. In diabetes, the insulin-producing beta cells of the pancreatic islets are unable to properly maintain normal blood glucose levels because of either insufficient beta cell number or insufficient beta cell function. Treating diabetes by replacing islets has been proposed as a therapeutic strategy, but transplantable material is limited. Understanding how to produce functional beta cells from alternate sources could bypass this limitation and enable islet replacement therapies. Current methods for in vitro generation of beta cells produce cells that express insulin, but that resemble fetal or neonatal beta cells with limited glucose-regulating capacity. This project will investigate the physiological and molecular signals that normally induce islets to transition from an immature less-functional state to a mature cell type capable of effective blood glucose regulation. To achieve this, we will first test whether mimicking normal glucose-induced cell depolarization by experimentally inducing scheduled electrical activity in cultured islets is sufficient to convert immature postnatal beta cells into mature and fully functional beta cells. Electrical activity will be controlled by expressing optogenetic proteins specifically in beta cells, which will produce an electrical current across the cell membrane when cells are exposed to a specific wavelength of light. Second, we will test whether activating the Calcineurin/NFAT signaling pathway, which senses cellular calcium levels and normally controls beta cell proliferation and function, is sufficient to promote maturation of cultured immature islets. These studies will reveal cellular and molecular stimuli that control how islets normally acquire function during development, and will inform efforts at generating new functional beta cells from renewable sources.