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

描述(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很大的提高。这些模型对于将生物医学的基本知识转化为人类疾病的预防或新疗法特别有用，并为疾病的病因和生物学提供了宝贵的见解。因此，根据R21计划公告(PA-07-336)“用于研究的动物模型和相关生物学模型的发展”，本探索性应用的目的是表征一种特定于β细胞的P53蛋白缺陷的小鼠模型，以直接检测其在胰岛素产生2细胞的功能、生长和存活中的作用。此外，根据计划公告的要求，鼠标模型将与两个不同的研究所-NIDDK和NCI-相关，最重要的是，该模型将根据联邦共享有机体的要求向研究社区提供。这位研究人员长期以来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。这些研究将与胰腺癌领域(NCI)的领导者D.Hanahan PhD(UCSF)进行磋商。因此，该应用程序符合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缓慢地被解开。由于在人体内研究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，显然没有提供对调控2-细胞生长的途径的真正见解。因此，包括我们实验室在内的许多研究人员都以小鼠为模型来研究介导2-细胞生长和凋亡的蛋白质和途径。虽然这一建议风险很高，因为在突变小鼠中可能没有主要的表型，但我们认为，根据我们的初步数据，这是不太可能的。相反，这些研究很可能会为与2-细胞生长和有丝分裂相关的途径提供关键线索。具体目标包括：可诱导的2细胞特异性p53基因敲除小鼠(I-2p53KO)的表型特征；检验2-细胞中可诱导的p53基因敲除可导致2-细胞增殖和潜在肿瘤形成的假说；检验高脂喂养阻止I-2p53KO小鼠2-细胞代偿性生长反应的假说；利用I-2p53KO小鼠的原代胰岛剖析生长因子信号转导通路与p53之间的联系的机制并鉴定蛋白质。与公共健康相关：该提案中概述的研究解决了胰岛生物学中的一个重要问题--了解胰岛素分泌的β细胞生长和增殖的途径和蛋白质。使用独特的基因工程小鼠模型和细胞生物学技术，我们将识别对理解途径至关重要的蛋白质，这些途径对于控制大量产生胰岛素的β细胞至关重要。拟议的研究旨在制定治疗策略以预防或延缓癌症和糖尿病的发展这一长期目标。

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.