Effects of Insulin Resistance on the 12/15-Lipoxygenase Pathway in Visceral Fat

胰岛素抵抗对内脏脂肪中 12/15-脂氧合酶途径的影响

• 批准号: 7328788
• 负责人: Michael D Williams
• 金额: $ 5.53万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7328788
• 关键词: Adipocytes; Animals; Arachidonate 15-Lipoxygenase; Atherosclerosis; C57BL/6 Mouse; Cardiovascular system; Central obesity; Condition; Coronary; Development; Diabetes Mellitus; Diet; Event; Fatty acid glycerol esters; Fluorescence-Activated Cell Sorting; Gene Expression; Genes; Harvest; Immunoassay; Immunohistochemistry; Incidence; Infiltration; Inflammation; Inflammatory; Insulin Receptor; Insulin Resistance; Interleukin-12; Link; Measures; Mediating; Metabolic syndrome; Modeling; Monocyte Chemoattractant Protein-1; Mus; Obesity; Pathway interactions; Play; Polymerase Chain Reaction; Population; Prevalence; Process; Production; Proteins; Public Health; Research; Risk; Role; Standards of Weights and Measures; Techniques; Testing; Thinking; Time; Transgenic Organisms; United States; Visceral; Week; chemokine; cytokine; feeding; insulin receptor substrate 1 protein; macrophage; mortality; mouse model; response; saturated fat; trafficking

DESCRIPTION (provided by applicant): Diabetes mellitus and obesity are increasing in prevalence, and are associated with increased risk for atherosclerotic cardiovascular disease. Activation of inflammatory processes in visceral fat is thought to contribute to the link between insulin resistance and atherosclerosis. The specific mechanisms involved in this inflammation, however, remain unclear. The hypothesis to be tested in the proposed research is that the 12/15-lipoxygenase (12/15-LO) pathway is important in mediating inflammatory changes in visceral fat, including cytokine production and macrophage infiltration, seen in states of insulin resistance. One specific aim is to evaluate the impact of varying degrees of insulin resistance on 12/15-LO pathway activation in visceral fat and in macrophages within visceral fat. Genetically insulin-resistant mice, which are heterozygous null at the insulin receptor and insulin receptor substrate-1 gene loci on the C57BL/6 background, will be fed along with wild-type C57BL/6 mice either a standard chow diet or a "western" diet which is high in saturated fat and precipitates or worsens insulin resistance. After either 15 or 30 weeks of feeding, visceral adipocytes and macrophages from visceral fat will be harvested, inflammatory gene expression will be measured using quantitative real-time PCR, and cytokine proteins will be studied by immunoassay. Trafficking of macrophages into visceral fat will be quantitated by fluorescence-activated cell sorting and immunohistochemistry. It is expected that more severely insulin-resistant animals will demonstrate higher levels of inflammatory activation. A second aim is to determine the importance of 12/15-LO activity in the inflammatory gene expression, cytokine production, and macrophage trafficking associated with insulin resistance. Mice which either have a deletion at the 12/15-LO gene locus or are transgenic for 12/15-LO, both on the C57BL/6 background, will be fed along with wild-type C57BL/6 mice either chow or the western diet. The techniques outlined above will be used to measure markers of inflammation. It is expected that visceral fat inflammatory activation in response to insulin resistance will vary directly with the genetically predetermined activity of 12/15-LO. This research has potential to identify the currently unclear inflammatory processes activated by insulin resistance in fat, and therefore facilitate specific targeted therapy to reduce development of atherosclerosis in the setting of diabetes and pre-diabetes. The ability to apply such measures to the population at large could greatly impact the currently increasing incidence of coronary events and cardiovascular mortality.

描述（由申请人提供）：糖尿病和肥胖症的患病率正在增加，并且与动脉粥样硬化心血管疾病的风险增加有关。内脏脂肪中炎症过程的激活被认为有助于胰岛素抵抗与动脉粥样硬化之间的联系。但是，这种炎症中涉及的具体机制尚不清楚。在拟议的研究中要检验的假设是，在介导内脏脂肪的炎症变化（包括细胞因子的产生和巨噬细胞浸润，在胰岛素抵抗状态下），12/15-脂氧合酶（12/15-LO）途径在介导内脏脂肪的炎症变化方面很重要。一个具体目的是评估不同程度的胰岛素抵抗对内脏脂肪和内脏脂肪内巨噬细胞中12/15-LO途径激活的影响。胰岛素受体和胰岛素受体底物-1基因座的杂合无效的遗传性胰岛素耐药小鼠将与野生型C57BL/6小鼠一起食用，或者是标准的鸡肉饮食或饱和脂肪中的高脂肪和降低的固有蛋白质的野生型C57BL/6小鼠。喂食15或30周后，将收集内脏脂肪细胞和巨噬细胞，并使用定量实时PCR来测量炎症基因表达，并通过免疫测定研究细胞因子蛋白。将巨噬细胞运输到内脏脂肪中，将通过荧光激活的细胞分选和免疫组织化学来定量。预计更严重的胰岛素动物将表现出更高水平的炎症激活。第二个目的是确定12/15-LO活性在炎症基因表达，细胞因子产生和与胰岛素抵抗相关的巨噬细胞运输中的重要性。在12/15-LO基因基因座上具有缺失的小鼠，或者在C57BL/6背景下为12/15-LO的转基因，将与野生型C57BL/6小鼠一起食用。上面概述的技术将用于测量炎症的标记。预计对胰岛素抵抗的响应内脏脂肪炎性激活将直接随12/15-LO的遗传预定活性而变化。这项研究有可能识别脂肪中胰岛素抵抗激活的当前不清楚的炎症过程，因此促进了特定的靶向疗法，以减少糖尿病和糖尿病前期动脉粥样硬化的发展。将此类措施应用于总体人口的能力可能会极大地影响冠状动脉事件和心血管死亡率的发生率增加。