Novel mechanisms to increase beta cell regeneration by p27

p27 促进 β 细胞再生的新机制

• 批准号: 8662377
• 负责人: Senta K Georgia
• 金额: $ 10.88万
• 依托单位: CHILDREN'S HOSPITAL OF LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-10 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8662377
• 关键词: Novel; mechanisms; increase; beta; cell

DESCRIPTION (provided by applicant): As of 2008, approximately 81 million people in the US have diabetes or pre-diabetes. As complications arising from diabetes represent the single largest cost to the US health care system, it is an imperative public health crisis to develop better therapies that treat, and potentially cure, the underlying cause of diabetes: hyperglycemia resulting from insufficient insulin production, due to either autoimmune destruction of insulin-producing beta cells or an inadequate mass of functional insulin-producing beta cells. This application seeks to improve our understanding of how to increase beta cell mass by investigating the mechanisms that govern the expansion of beta mass during embryogenesis and in response to diet-induced insulin resistance. Specifically, we propose to investigate how mechanisms that govern the accumulation or degradation of p27, a protein that functions to inhibit the expansion of beta cell mass, can be exploited to expand beta cell mass. We propose that Spy1A, a cell novel cell cycle regulator that can bypass p27-mediated inhibition of cell expansion, can be overexpressed to increase beta cell mass. We have also identified that Rap1A, a small GTPase activated during beta cell differentiation, may induce cell cycle arrest by upregulation of p27. We will use transgenic mouse models to investigate if spy1A overexpression or rap1A deletion can increase beta cell mass. We have discovered previously unidentified roles for skp2 and p27 in enteroendocrine differentiation from gut progenitor cells, which will serve as an alternative in vivo model to understand how beta cells may differentiate from adult progenitor cells to expand beta cell mass. We will use purified cell populations, cell culture models, lentiviral transfections, and siRNA knockdown experiments to assess how these proteins activate or repress p27 transcription and degradation. We expect that the results from the proposed aims of this grant will directly contribute to potential therapies to regenerate functional beta cell mass for diabetic patients. The theme of this research directly addresses the Beta Cell Therapy Research Program programmatic thrust of the NIDDK's division of Diabetes, Endocrinology and Metabolic Diseases. The research proposed in this grant will foster the transition of Dr. Senta K. Georgia from junior faculty to an independent research career. The theme of this grant is an extension of her established publication record in the field of beta cell differentiation and regeneration. Though she is building on her previous publication record, the experiments proposed in this application expose her to new techniques and new model systems for understanding beta cell differentiation and expansion. Under the mentorship of Dr. Mart¿n Mart¿n and co-mentorship of Dr. Anil Bhushan, Dr. Georgia will pursue cutting edge research at UCLA, with access to state-of-the-art equipment, cores, and resources to facilitate the production and analysis of data. In addition to her research, this proposal outlines specific mentorship activities that will foster Dr. Georgia's independence, including (but not limited to) attendance at new investigator workshops, presentation of her work at relevant international conferences, and detailed benchmarking of her progress by a personalized career development plan. We expect that the research proposed in this application will result in 3 high impact publications within the next 5 years that will advance the field of regenerative medicine and islet biology. With protected research time, freedom from the responsibility of didactic teaching responsibilities, participation in intellectually stimulating and education seminars, exposure to new model systems and new techniques, immersion in a stimulating and supportive environment, and active mentorship to encourage critical assessment of data and publication, we are very confident that Dr. Georgia will be an outstanding candidate for a tenure track independent research position at the end of the granting period of this award. PUBLIC HEALTH RELEVANCE: The 81 million Americans that are diabetic or are pre-diabetic suffer from the condition because the body's insulin-producing cells, either because of autoimmune destruction or the inability of the cells to function properly, are unable to maintain normal blood sugar levels. The proposed studies are targeted to understand how functional insulin-producing cells normally reproduce themselves. Results from these studies will contribute to the design of therapies to generate more insulin-producing cells as an effective cure for diabetes.

描述（由申请人提供）：截至 2008 年，美国约有 8100 万人患有糖尿病或糖尿病前期。由于糖尿病引起的并发症是美国医疗保健系统最大的单一成本，因此迫切需要开发更好的疗法来治疗并可能治愈糖尿病的根本原因：由于产生胰岛素的β细胞的自身免疫性破坏或产生胰岛素的功能性β细胞质量不足而导致胰岛素产生不足而导致的高血糖。 该应用旨在通过研究胚胎发生过程中控制β细胞质量扩张以及响应饮食诱导的胰岛素抵抗的机制，提高我们对如何增加β细胞质量的理解。具体来说，我们建议研究如何利用控制 p27（一种抑制 β 细胞质量扩张的蛋白质）积累或降解的机制来扩大 β 细胞质量。我们提出，Spy1A 是一种新型细胞周期调节因子，可以绕过 p27 介导的细胞增殖抑制，可以过表达以增加 β 细胞质量。我们还发现 Rap1A（一种在 β 细胞分化过程中激活的小 GTP 酶）可能通过上调 p27 诱导细胞周期停滞。我们将使用转基因小鼠模型来研究spy1A过度表达或rap1A缺失是否可以增加β细胞质量。我们发现了之前未确定的 skp2 和 p27 在肠道祖细胞肠内分泌分化中的作用，这将作为另一种体内模型来了解 β 细胞如何从成体祖细胞分化以扩大 β 细胞质量。我们将使用纯化的细胞群、细胞培养模型、慢病毒转染和 siRNA 敲低实验来评估这些蛋白质如何激活或抑制 p27 转录和降解。我们预计这笔赠款拟议目标的结果将直接有助于糖尿病患者再生功能性 β 细胞团的潜在疗法。这项研究的主题直接涉及 NIDDK 糖尿病、内分泌和代谢疾病部门的 Beta 细胞治疗研究计划的计划主旨。 这笔赠款中提出的研究将促进 Senta K. Georgia 博士从初级教师向独立研究职业的转变。这笔资助的主题是扩展她在 β 细胞分化和再生领域已建立的出版记录。尽管她是在之前的发表记录的基础上进行的，但本申请中提出的实验使她接触到了理解 β 细胞分化和扩增的新技术和新模型系统。在 Martn Martn 博士和 Anil Bhushan 博士的共同指导下，Georgia 博士将在加州大学洛杉矶分校进行前沿研究，获得最先进的设备、核心和资源，以促进数据的生成和分析。除了她的研究之外，该提案还概述了促进乔治亚博士独立性的具体指导活动，包括（但不限于）参加新研究者研讨会、在相关国际会议上介绍她的工作，以及通过个性化职业发展计划对她的进展进行详细基准测试。 我们预计本申请中提出的研究将在未来 5 年内发表 3 篇高影响力的出版物，从而推动再生医学和胰岛生物学领域的发展。凭借受保护的研究时间、免于教学责任的自由、参与智力刺激和教育研讨会、接触新模型系统和新技术、沉浸在刺激和支持性环境中，以及鼓励对数据和出版进行批判性评估的积极指导，我们非常有信心乔治亚博士将在该奖项授予期结束时成为终身教授独立研究职位的杰出候选人。 公共健康相关性：8100 万美国人患有糖尿病或糖尿病前期，因为体内的胰岛素产生细胞由于自身免疫破坏或细胞无法正常运作而无法维持正常的血糖水平。拟议的研究旨在了解功能性胰岛素生成细胞如何正常自我繁殖。这些研究的结果将有助于治疗方法的设计，以产生更多的胰岛素产生细胞，作为糖尿病的有效治疗方法。