The role of GATA6 and GATA4 in pancreatic beta cell function and development

项目摘要/摘要 GATA6和GATA4是锌指转录因子GATA家族的两个成员，具有 已被证明对胰腺发育很重要。GATA6和GATA6基因杂合性突变 GATA4在胰腺发育不全患者中占大多数。然而，GATA6和 GATA4显然在胰腺发育和功能中扮演着更复杂的角色 杂合子突变可导致某些个体的不同起病和严重程度的糖尿病 胰腺发育不全，即使在携带相同突变的家庭成员中也是不同的。影响因素 单倍体功能不全引起的疾病可能是特别重要的治疗目标 它们行为的改变可能是疾病和正常功能之间的区别。因此， 了解GATA因子的作用将促进我们对β细胞功能的了解。尽管 这些蛋白质已经在小鼠身上进行了研究，它们不能概括人类的表型，使 对人类细胞的研究是必要的。区分人类多能性的技术的发展 干细胞(HPSCs)进入胰腺细胞允许使用人类系统，在其中 完成这些调查。我们小组的初步数据显示，GATA6是 HPSCs分化过程中内胚层的正常诱导和GATA6的缺失导致缺陷 葡萄糖刺激分化的胰岛β细胞胰岛素分泌。此外，初步的 研究表明，维甲酸可以诱导GATA6和GATA4的表达 参与胰腺细胞分化的信号，提示两者之间存在相互作用 小路。这项提案中描述的研究将使用两种人体模型的胰腺β细胞， 研究GATA6和GATA4在hPSCs和人β细胞系中的作用 并确定GATA因子和GATA因子之间的相互作用 维甲酸信号。通过选择性地敲除和过度表达成熟期的GATA因子 我们将能够确定它们对胰岛素分泌的影响，而不是依赖于它们的 对发展的影响。在分化和成熟的胰岛β细胞中使用同样的技术 细胞在修饰维甲酸信号时，我们将能够表征相互作用 GATA4/6和维甲酸。这些研究将有助于增进我们对胰岛β细胞的了解。 功能和发育，因此允许更好地理解病理生理学 由他们的功能障碍引起的潜在疾病，包括糖尿病。

Project Summary/Abstract GATA6 and GATA4 are two members of the GATA family of zinc finger transcription factors and have been shown to be important for pancreatic development. Heterozygous mutations in GATA6 and GATA4 account for the majority of cases of patients with pancreatic agenesis. However, GATA6 and GATA4 clearly play a more complex role in pancreatic development and function as these same heterozygous mutations can result in diabetes of varying onset and severity in some individuals without pancreatic agenesis, differing even within family members carrying the same mutations. Factors that cause disease due to haploinsufficiency can be particularly important therapeutic targets as small modifications in their action could be the difference between disease and normal function. Therefore, understanding the role of the GATA factors will advance our knowledge of beta cell function. Though these proteins have been studied in mice, they do not recapitulate the human phenotype, making studies in human cells necessary. The development of techniques to differentiate human pluripotent stem cells (hPSCs) into pancreatic cells has allowed for the use of a human system in which to accomplish these investigations. Preliminary data from our group show that GATA6 is necessary for normal endoderm induction during differentiation of hPSCs, and that loss of GATA6 results in defective glucose-stimulated insulin secretion in differentiated pancreatic beta cells. Additionally, preliminary studies show that GATA6 and GATA4 expression can be induced by retinoic acid, one of the inductive signals involved in the differentiation of pancreatic cells, suggesting interaction between the two pathways. The research described in this proposal will use two human models of pancreatic beta cells, differentiated hPSCs and a human beta cell line, to characterize the role of GATA6 and GATA4 in glucose-stimulated insulin secretion and to define the interaction between the GATA factors and retinoic acid signaling. By selectively knocking down and overexpressing the GATA factors in mature pancreatic beta cells, we will be able to determine their effect on insulin secretion independent of their effect on development. Utilizing this same technique in both differentiating and mature pancreatic beta cells while modifying retinoic acid signaling, we will be able to characterize the interaction between GATA4/6 and retinoic acid. These studies will help advance our knowledge of pancreatic beta cell function and development and therefore allow for a better understanding of the pathophysiology underlying diseases resulting from their dysfunction, including diabetes.