ATF5 in the developing pancreas and survival functions in the mature beta cell.

描述(由申请人提供)：胰腺胰岛素分泌细胞的正常功能、发育和存活对于预防糖尿病至关重要。因此，这些功能的中介对于了解糖尿病的发展和发现可行的治疗方法是非常重要的。激活转录因子5(ATF5)是一种转录因子，在嗅觉神经元、造血细胞和多种肿瘤中显示出抗凋亡、促存活和分化的作用。初步数据表明，ATF5在胚胎胰腺发育过程中表达，在成熟的？细胞中表达，并在胰岛表达丰富。然而，ATF5在发育和成熟的胰腺中的作用尚不清楚。该提案的目标1将通过对一只可获得的全局Atf5/-小鼠与WT胎在整个妊娠发育过程中的胰腺和胰岛的形态和基因表达进行分析，确定ATF5在胰腺发育中的作用。结果将描绘ATF5在胰腺、内分泌室和胰岛结构发育中重要的特定靶点。初步数据表明，ATF5是PDX1在成熟细胞中调控的直接靶点。已知PDX1在成熟的？细胞中具有促生存作用，与内质网应激敏感性有关。该提案的目标2将重点放在PDX1促进生存的作用和ATF5调控的成熟细胞在压力刺激(如营养剥夺、氧化应激、内质网应激)背景下的调节作用。通过ATF5在成熟细胞中的过表达挽救PDX1缺乏所导致的表型，将揭示ATF5在PDX1信号通路和促生存功能中的作用。ATF5将通过免疫荧光染色、免疫沉淀、分级和质谱学进一步表征，以揭示以前未知的结合伙伴、细胞内的亚细胞定位和激活机制。这一建议对于在有害刺激和可能的糖尿病预防性治疗的背景下操纵？细胞存活的一组新靶点的发现具有重要意义。

DESCRIPTION (provided by applicant): Proper function, development, and survival of the pancreatic insulin secreting ß-cell is critical for the prevention of diabetes. Thus mediators of these functions are highly important in the understanding of diabetes development and for discovery of feasible therapies. Activating transcription factor 5 (ATF5) is a transcription factor that has demonstrated anti-apoptotic, pro-survival, and differentiation roles in olfactory sensory neurons, hematopoietic cells, and several cancers. Preliminary data indicate that ATF5 is expressed during embryonic pancreatic development, in mature ß-cells, and enriched in pancreatic islets. However, the role of ATF5 in the developing and mature pancreas is not known. Aim 1 of this proposal will determine the role of ATF5 in pancreatic development through morphological and gene expression analysis of the pancreas and islets of an available global Atf5-/- mouse compared to WT littermates throughout gestational development. Results will delineate the specific targets important for ATF5 in the development of the pancreas, endocrine compartment, and islet architecture. Preliminary data indicate that ATF5 is a direct target of regulation by PDX1 in the mature ß-cell. PDX1 is known to have pro-survival roles pertaining to ER stress susceptibility in the mature ß-cell. Aim 2 of this proposal will focus on the mediation of PDX1 pro-survival roles and targets regulated by ATF5 in the mature ß-cell in the context of stress stimuli (e.g. nutrient deprivation, oxidative stress, ER stress) known to be detrimental to the ß-cell. Rescue of phenotypes resulting from PDX1 deficiency by overexpression of ATF5 in mature ß-cells will reveal the role of ATF5 in PDX1 signaling pathways and pro- survival functions. ATF5 will be further characterized by immunofluorescent staining, immunoprecipitation, fractionation, and mass spectrometry to reveal previously unknown binding partners, subcellular localization within the cell, and mechanisms of activation. This proposal is important as a point of discovery for a new set of targets for manipulation of ß-cell survival in the context of deleterious stimuli as well as possible preventive therapies for diabetes.