Characterization of the inducible-beta-cell-specific p53 knockout mice

描述（由申请人提供）：用于研究与疾病相关的蛋白质功能的基因工程小鼠模型的发展在过去十年中有了相当大的增长。这些模型对于将生物医学基础知识转化为人类疾病的预防或新的治疗方法特别有用，并对疾病的病因和生物学提供宝贵的见解。因此，根据R21计划公告（PA-07-336）“开发动物模型和相关生物学模型用于研究”，本探索性应用的目的是表征β细胞中特异性缺乏p53蛋白的小鼠模型，以直接研究其在产生胰岛素的2细胞的功能、生长和存活中的作用。此外，根据项目公告的要求，小鼠模型将与两个不同的研究所相关- NIDDK和NCI -最重要的是，该模型将根据联邦共享生物要求提供给研究界。长期以来，研究者一直对胰岛细胞中与2型糖尿病（NIDDK）相关的生长因子信号通路感兴趣。这些研究将在D. Hanahan博士（UCSF）的指导下进行，他是胰腺癌领域（NCI）的领导者。因此，该应用程序满足了PA的所有重要要求。与2细胞生长和再生相关的机制和蛋白质只是慢慢地被解开。由于在人体体内研究2细胞生长几乎是不可能的，大多数研究都是基于培养的人类胰岛，显然不能提供调节2细胞生长途径的真正见解。因此，包括我们实验室在内的许多研究人员已经使用小鼠作为模型来研究介导2细胞生长和凋亡的蛋白质和途径。虽然这一建议是高风险的，因为突变小鼠可能没有主要表型，但根据我们的初步数据，我们认为这不太可能。相反，这些研究极有可能为与2细胞生长和有丝分裂相关的途径提供关键线索。具体目的包括：诱导2细胞特异性p53敲除小鼠（i-2p53KO）的表型表征；验证诱导敲除2细胞p53导致2细胞增殖和潜在肿瘤形成的假设；验证高脂肪喂养阻止i-2p53KO小鼠代偿性2细胞生长反应的假设；使用来自i-2p53KO小鼠的原代胰岛解剖机制并鉴定将生长因子信号通路与p53联系起来的蛋白质。公共卫生相关性：本提案中概述的研究解决了胰岛生物学中的一个重要问题-了解胰岛素分泌β细胞生长和增殖的途径和蛋白质。利用独特的基因工程小鼠模型和细胞生物学技术，我们将识别出对理解胰岛素生成β细胞质量控制至关重要的途径至关重要的蛋白质。拟议的研究旨在制定预防或延缓癌症和糖尿病发展的治疗策略的长期目标。

DESCRIPTION (provided by applicant): The development of genetically engineered mouse models for research into the function of proteins relevant for diseases has risen considerably over the last decade. These models are particularly useful for the translation of basic knowledge biomedical to prevention or new treatments for human disease and provide invaluable insights into the cause and biology of diseases. Thus, in accordance with the R21 program announcement (PA-07-336) "Development of animal models and related biological models for research" the objective of this exploratory application is to characterize a mouse model deficient for p53 protein specifically in beta cells to directly examine its role in function, growth and survival of insulin-producing 2-cells. Further, as required by the program announcement, the mouse model will be relevant to two different institutes - NIDDK and NCI - and most importantly, the model will be made available to the research community in accordance with the federal shared organism requirements. The investigator has a long-standing interest in growth factor signaling pathways in islet cells that is relevant to type 2 diabetes (NIDDK). The studies will be performed in consultation with D. Hanahan PhD (UCSF), a leader in the pancreatic cancer field (NCI). Thus, this application meets all the important requirements of the PA. The mechanisms and proteins relevant for 2-cell growth and regeneration are only slowly being unraveled. Since in vivo studies in humans to examine 2-cell growth are virtually impossible most studies are based on cultured human islets and obviously do not provide true insights in the pathways regulating 2-cell growth. Therefore, many investigators including our laboratory have used mice as models to examine the proteins and pathways that mediate 2-cell growth and apoptosis. While this proposal is high risk because there may be no major phenotype in the mutant mice, we believe this is unlikely based on our preliminary data. On the contrary, it is highly likely the studies will yield crucial clues to the pathways that are relevant for 2-cell growth and mitosis. The Specific Aims include: Phenotypic characterization of inducible 2-cell-specific p53 knockout mice (i-2p53KO); test the hypothesis that inducible knockout of p53 in 2-cells leads to 2-cell proliferation and potential tumor formation; Test the hypothesis that high fat feeding prevents compensatory 2-cell growth response in i-2p53KO mice; Dissect the mechanisms and identify proteins that link growth factor signaling pathways with p53 using primary islets derived from i-2p53KO mice. PUBLIC HEALTH RELEVANCE: The studies outlined in this proposal address an important problem in islet biology - understanding the pathways and proteins that underlie the growth and proliferation of insulin-secreting beta-cells. Using unique genetically engineered mouse models and cell biological techniques we will identify the proteins that are critical for understanding the pathways that are critical for the control of mass of insulin-producing beta-cells. The proposed studies are aimed at the long-term goal of developing therapeutic strategies to prevent or delay the development of cancer and diabetes.