The Role of Laminin Alpha 4 in Beta-cell Function and Survival

2型糖尿病的患病率在美国迅速增加，影响了至少8%的美国人。 人口该病的发病机制包括肥胖和胰岛素抵抗，但β细胞功能受损， 分泌功能和存活对于高血糖症的发展至关重要。的机制 β细胞功能障碍和死亡仍然不完全清楚，提高我们对这些问题的认识， 这是为这种潜在的衰弱性疾病开发更好疗法的基础。 胰岛细胞外基质（ECM）几乎完全由胰岛内皮细胞合成，是一种重要的细胞外基质。 β细胞的重要信号来源。胰岛细胞外基质成分层粘连蛋白通常促进胰岛素释放 和β细胞存活率。我对2型糖尿病动物模型胰岛内皮细胞的初步数据显示， 这是第一次层粘连蛋白α4的产生减少。此外，在体外培养原代胰岛内皮细胞， 高葡萄糖也导致层粘连蛋白α4产生减少。永生化胰岛中层粘连蛋白α4的敲除 内皮细胞导致胰岛素释放受损，并且在层粘连蛋白α4敲除小鼠中胰岛素释放受损。 因此，我推测，增加胰岛内皮细胞来源的ECM中层粘连蛋白α4的产生， 在高血糖条件下改善β细胞功能。我将通过承诺来解决这个假设 研究确定在高糖培养的原代胰岛内皮细胞中层粘连蛋白α4的过度表达是否 足以在体外改善β细胞功能。关键的是，我还将确定胰岛内皮细胞的感染 层粘连蛋白α4的长期细胞特异性AAV表达改善了体内胰岛素释放。我预计 这些研究将首次证明，增加层粘连蛋白α4的表达足以改善 糖尿病条件下的β细胞功能和存活。 该提案概述了一个全面的13个月计划，重点是科学和专业 发展这项研究将扩大我们对胰岛内皮细胞在胰岛细胞增殖中的作用的理解。 β细胞功能和生存，同时促进我获得胰岛生物学的科学技能，这对我来说是一个新领域。 博士船体在胰岛生物学方面的专业知识以及她提供的特殊指导环境， 我的共同赞助人卡恩博士，将有助于完成这个项目，并对我的职业发展。 参加研讨会、实验室会议、区域和国家会议，以及由NIDDK主办的活动- 糖尿病研究中心（DRC）和营养肥胖研究中心（NORC）在大学的资助 华盛顿将提供丰富的培训和职业发展经验。这些活动将共同 使我能够成功地竞争职业发展（K）奖，并朝着我的目标前进， 成为一个独立的研究者在代谢与重点胰岛生物学。

The prevalence of type 2 diabetes is increasing rapidly in the United States, affecting at least 8% of the population. The pathogenesis of the disease includes obesity and insulin resistance, but impairments in β-cell secretory function and survival are critical for the development of hyperglycemia. The mechanisms underlying β-cell dysfunction and death remain incompletely understood, and improving our knowledge of these is fundamental for the development of better therapies for this potentially debilitating disease. The islet extracellular matrix (ECM), synthesized almost exclusively by the islet endothelial cell, is an important source of signals for the β cell. The islet ECM component laminin normally enhances insulin release and β-cell survival. My preliminary data in islet endothelial cells from animal models of type 2 diabetes show for the first time that laminin α4 production is decreased. Additionally, culturing primary islet endothelial cells in high glucose also results in decreased laminin α4 production. Knockdown of laminin α4 in immortalized islet endothelial cells results in impaired insulin release, and insulin release is impaired in laminin α4-knockout mice. Thus, I hypothesize that increasing laminin α4 production in islet endothelial-derived ECM will improve β-cell function under hyperglycemic conditions. I will address this hypothesis by undertaking studies to determine if overexpression of laminin α4 in primary islet endothelial cells cultured in high glucose is sufficient to improve β-cell function in vitro. Critically, I will also determine if infection of islet endothelial cells with a long-term cell-specific AAV expression of laminin α4 improves insulin release in vivo. I anticipate that these studies will demonstrate for the first time that increasing expression of laminin α4 is sufficient to improve β-cell function and survival under diabetic conditions. This proposal outlines a comprehensive thirteen month plan focused on scientific and professional development. The proposed studies will expand our understanding of the islet endothelial cell's contribution to β-cell function and survival, while facilitating my acquisition of scientific skills in islet biology, a new field for me. Dr. Hull's expertise in islet biology together with the exceptional mentoring environment provided by her and my co-sponsor Dr. Kahn, will contribute to the completion of this project, and to my career development. Participation in seminars, lab meetings, regional and national meetings, and events sponsored by the NIDDK- funded Diabetes Research Center (DRC) and Nutrition Obesity Research Center (NORC) at the University of Washington will contribute to a rich training and career development experience. Together, these activities will enable me to successfully compete for a Career Development (K) Award and progress towards my goal of becoming an independent investigator in metabolism with a focus on islet biology.