The role of Spry2 in beta cell function and the unfolded protein response

 说明（由申请人提供）胰腺β细胞是生理水平胰岛素的唯一生产者。2型糖尿病的发生是由于胰岛β细胞在胰岛素抵抗增加的情况下出现功能障碍。目前没有糖尿病药物可以预防β细胞衰竭。 我们建议进一步了解控制正常β细胞功能的途径将允许更合理地设计可以预防β细胞衰竭的糖尿病疗法。为此，我们进行了全基因组RNA干扰筛选，并将Spry 2鉴定为胰岛素产生的新型调节剂。有趣的是，Spry 2附近的单核苷酸多态性（SNP）与2型糖尿病相关，表明它在糖尿病发病机制中起作用。我们在胰岛素转录的最高调节因子之间生成了一个系统性遗传相互作用图，以了解Spry 2可能如何发挥作用。该图谱预测Spry 2可能与Wfs 1相互作用，Wfs 1是一种已知通过激活未折叠蛋白反应（UPR）引起人类糖尿病的基因。事实上，我们表明，Spry 2是由普遍定期审议和调节。该提案的总体目标是确定Spry 2在β细胞功能、UPR和人类糖尿病中的作用和机制。具体来说，我们假设Spry 2通过与Wfs 1的相互作用对β细胞功能和UPR很重要。我们的具体目标是：目标1：证明Spry 2在体内β细胞功能中的作用。我们将表征Spry 2的β细胞特异性敲除。目的2：阐明Spry 2对UPR的作用机制。我们将测试Wfs 1/Spry 2相互作用的功能重要性，并绘制其调节UPR所需的Spry 2位点。目的3：检测Spry 2在人类胰岛中的功能，并鉴定Spry 2附近控制Spry 2表达的致病SNP。在目标的第一部分中，我们将减少人类胰岛中的Spry 2表达，并测量胰岛素的产生，分泌和未折叠蛋白反应。在目标的第二部分，我们将使用基因组编辑来测试潜在的致病性2型糖尿病SNPs调节Spry 2表达的能力。该提案的贡献是将Spry 2确立为β细胞UPR和2型糖尿病发病机制中的新参与者。

 DESCRIPTION (provided by applicant) The pancreatic beta cell is the sole producer of physiologic levels of insulin. Type 2 diabetes develops when the pancreatic beta cell fails in the setting of increased insulin resistance. No current diabetes medication prevents beta cell failure. We propose that further understanding the pathways that control normal beta cell function will allow the more rational design of diabetes therapies that can prevent beta cell failure. To that end, we performed a whole genome RNA interference screen and identified Spry2 as a novel regulator of insulin production. Intriguingly, a single nucleotide polymorphism (SNP) near Spry2 is associated with type 2 diabetes, suggesting that it plays a role in diabetes pathogenesis. We generated a systemic genetic interaction map between top regulators of insulin transcription to understand how Spry2 might function. This map predicts that Spry2 may interact with Wfs1, a gene known to cause human diabetes via activation of the unfolded protein response (UPR). Indeed, we show that Spry2 is regulated by and regulates the UPR. The overall objective of this proposal is to define the role and mechanism of Spry2 in beta cell function, the UPR, and human diabetes. Specifically, we hypothesize that Spry2 is important for beta cell function and the UPR through an interaction with Wfs1. Our specific aims are: Aim 1: Demonstrate a role for Spry2 in beta cell function in vivo. We will characterize a beta cell specific knockout of Spry2. Aim 2: Elucidate the mechanism of Spry2 action on the UPR. We will test the functional importance of a Wfs1/Spry2 interaction and map the sites of Spry2 that are required for its modulation of the UPR. Aim 3: Test the function of Spry2 in human islets and identify the causative SNP near Spry2 that controls Spry2 expression. In the first part of the aim we will reduce Spry2 expression in human islets and measure insulin production, secretion and the unfolded protein response. In the second part of the aim, we will use genome editing to test potential causative type 2 diabetes SNPs for their ability to modulate Spry2 expression. The contribution of this proposal is the establishment of Spry2 as a new player in the beta cell UPR and in the pathogenesis of type 2 diabetes.