Macrovascular Dysfunction of Diabetes

描述（由申请人提供）：我们的长期目标是研究胰岛素信号在血管组织对其他更有效的有丝分裂原的细胞反应中的作用机制。我们最近的研究表明，胰岛素可以增强PDGF和VEGF在血管平滑肌细胞（VSMC）和内皮细胞（EC）中的作用。因此，我们希望确定这些细胞内串扰的机制，确定治疗药物的分子靶点，并有助于理解糖尿病血管疾病的病理生理。我们假设，代谢胰岛素抵抗状态下的高胰岛素血症，通过增加戊烯基转移酶活性，增强了更有效的有丝分裂原对脉管系统的影响，从而增加了可用于有丝分裂原刺激的GTPloading的戊烯基化Ras和Rho蛋白的数量，导致夸大的细胞反应，导致动脉粥样硬化的发生和进展。我们将测试这个假设使用的两个重要工具:(1)的显性负突变alpha-subunit (DNFTa)治疗(简称ftis)和geranylgeranyltransferase我(GGTase I)帮助确定保险机制,联系其他生长因子信号通路途径,和(2)一个tetracyline-inducible系统来确定什么效果的表达DNFTa在稳定转染血管平滑肌细胞在insulin-stimulation Erk5途径。为了确定这些机制，我们确定了三个主要的具体目标：(1)在胰岛素抵抗的情况下，DNFTa是否抑制高胰岛素血症增强大鼠主动脉血管平滑肌细胞RASMC中其他生长因子的有丝分裂作用的能力；(2)在胰岛素抵抗的情况下，DNFTa是否抑制高胰岛素血症增强其他生长因子在大鼠肺主动脉血管内皮细胞PAVEC中有丝分裂作用的能力；(3)在存在胰岛素抵抗的情况下，DNFTa是否抑制胰岛素刺激的RASMC中Erk5的磷酸化、激活和易位。

DESCRIPTION (provided by applicant): Our long-term goal is to investigate the mechanisms by which insulin signaling effects changes in cellular responses of vascular tissue to other more potent mitogens. We have recently shown that insulin augments the actions of PDGF and VEGF in vascular smooth muscle cells (VSMC) and endothelial cells (EC). Thus, we would like to determine these mechanisms of cross-talk within these cells, determine molecular targets for therapeutic drugs and contribute to the understanding of the pathophysiology of vascular disease in diabetes. We hypothesize that hyperinsulinemia in the state of metabolic insulin resistance, augments the effects of more potent mitogens on the vasculature via increases in prenyltransferase activity, thereby increasing the amounts of prenylated Ras and Rho proteins that are available for mitogen-stimulated GTPloading, resulting in exaggerated cellular responses that lead to the development and progression of atherosclerosis. We will test this hypothesis using two important tools: (1) a dominant-negative mutant of the alpha-subunit (DNFTa) of farnesyltransferase (FTase) and geranylgeranyltransferase I (GGTase I) to help determine the mechanisms that link the insuring signaling pathway to other growth factor pathways, and (2) a tetracyline-inducible system to determine what effects does the expression of DNFTa in stably transfected vascular smooth muscle cells have upon insulin-stimulation of the Erk5 pathway. To determine these mechanisms we have defined three major Specific Aims: (1) Does DNFTa inhibit hyperinsulinemia's ability to potentiate the mitogenic effects of other growth factors in rat aorta vascular smooth muscle cells RASMC in the presence of insulin resistance; (2) Does DNFTa inhibit hyperinsulinemia's ability to potentiate the mitogenic effects of other growth factors in rat pulmonary aortic vascular endothelial cells PAVEC in the presence of insulin resistance; and (3) Does DNFTa inhibit insulin-stimulated phosphorylation, activation and translocation of Erk5 in RASMC in the presence of insulin resistance.