Role of the Unfolded Protein Response in Type 2 Diabetes

描述(由申请人提供)： Feroz R.Papa博士是一名内分泌学家，坚定地致力于作为(细胞分子生物学)独立研究员的学术生涯。他特别感兴趣的是内质网(ER)应激在2型糖尿病(DM2)发展中的作用。因此，他在彼得·沃尔特博士的实验室里发起了一项博士后研究计划。加州大学旧金山分校生物化学和生物物理学教授，研究未折叠蛋白反应(UPR)，这是一种真核细胞调整内质网应激的动态平衡机制。内质网应激发生在内质网管腔中正在成熟的客户蛋白的负荷和内质网处理这一负荷的能力之间的不平衡。引发内质网应激的病理生理条件包括缺氧、营养缺乏和多肽突变，这些都会导致蛋白质错误折叠。UPR通过两种机制重塑ER的环境，以响应ER压力：1)编码ER伴侣、酶活性和结构ER成分的基因转录上调；2)整体翻译暂停，从而减少ER客户蛋白的负荷。ER-跨膜蛋白激酶/内切核酸酶Ire1α是UPR转录臂的传感器，ER-跨膜ELF-2α激酶Perk是翻译臂的传感器。Papa博士正在提出一项研究计划，该计划将解决这样一种假设，即使用小分子效应器实时调节UPR可以影响β细胞的功能，最终影响它们的存活。他将通过三个具体目标来解决这一假设。首先，使用化学遗传策略，他将通过将IRE1α基因靶向于一种细胞渗透性的ATP类似物1-NM PP1来敏化Ire1pha，他已经证明，1-NM PP1是通过在酵母中敏化IRE1来传递信号的允许辅助因子。β细胞特异性基因打靶将使该组织在没有1 nm-PP1的情况下无法向UPR的转录臂发出信号。第二，将进行类似的PERK基因打靶，赋予UPR的翻译臂药理学条件。第三，这些操作对β细胞的生物学后果将在这些敲入突变体中进行研究，并在另外三个小鼠突变体的遗传背景中进行研究，这些突变体由于未受控制的内质网应激而产生DM2：Akita、hlAPP和PERK-/-。综上所述，这项工作有望为专业分泌组织(包括但不限于β细胞)如何适应生理和病理生理压力提供重要的见解。爸爸博士将在部门进行这项工作。在Peter Walter博士的指导下，并与Robert Farese，Jr.博士合作，在加州大学旧金山分校担任生物化学和生物物理学教授。格拉斯顿心血管疾病研究所的Kavan Shokat博士和细胞和分子药理学系的Kevin Shokat博士。加州大学旧金山分校医学部完全致力于Papa博士的职业发展，并将提供所有必要的资源，以促进该项目的成功。

DESCRIPTION (provided by applicant): Dr. Feroz R. Papa is an endocrinologist, strongly committed to an academic career as an independent investigator in (-cell molecular biology. His specific interest is the role of endoplasmic reticulum (ER) stress in development of diabetes mellitus type 2 (DM2). Accordingly, he has initiated a postdoctoral fellowship in the lab of Dr. Peter Walter, in the Dept. of Biochemistry and Biophysics at UCSF, studying the Unfolded Protein Response (UPR), a homeostatic mechanism through which eukaryotic cells adjust to ER stress. ER stress occurs when there is an imbalance between the load of client proteins undergoing maturation in the ER lumen and the capacity of the ER to process this load. Pathophysiological conditions provoking ER stress include anoxia, nutrient deprivation, and polypeptide mutations, which result in protein misfolding. The UPR remodels the environment of the ER to respond to ER stress through two mechanisms: 1) a transcriptional upregulation of genes encoding ER chaperones, enzymatic activities, and structural ER components, and 2) a global translational halt, which reduces the load of ER client proteins. The ER-transmembrane kinase/endoribonuclease Ire1alpha is the sensor for the transcriptional arm of the UPR, and the ER-transmembrane elF-2alpha kinase Perk is the sensor for the translational arm. Dr. Papa is proposing a research program which will address the hypothesis that modulating the UPR, in real time using small molecule effectors, can influence the function of beta-cells, and ultimately their survival. He will address this hypothesis through three specific aims. First, using a chemical-genetic strategy, he will sensitize Ire1alpha by gene targeting of IRE1alpha to a cell-permeable ATP analog, 1-NM PP1, which he has demonstrated is a permissive co-factor for signaling by sensitized Ire1 in yeast. Beta-cell-specific gene targeting would render this tissue unable to signal the transcriptional arm of the UPR in the absence of 1NM-PP1 Second, similar gene targeting of PERK will be conducted, conferring pharmacological conditionality on the translational arm of the UPR. Third, the biological consequences of these manipulations on beta-cells will be studied in these knock-in mutants, and in the genetic background of three other mouse mutants which develop DM2 as a consequence of unchecked ER stress: Akita, hlAPP, and perk-/-. Together this work promises to yield important insights into how professional secretory tissues (including, but not limited to beta-cells) adapt to physiological and pathophysiological stresses. Dr. Papa will conduct this work in the Dept. of Biochemistry and Biophysics at UCSF under the mentorship of Dr. Peter Walter, and in collaboration with Dr. Robert Farese, Jr. in the Gladstone Institute of Cardiovascular Disease, and Dr. Kevan Shokat in the Department of Cellular and Molecular Pharmacology. The UCSF Department of Medicine is fully committed to Dr. Papa's career development, and will make all necessary resources available to facilitate the success of the project.