Atypical PKC Knockout Models: Effect on Glucose and Lipid Homeostasis

非典型 PKC 敲除模型：对血糖和脂质稳态的影响

• 批准号: 8762424
• 负责人: ROBERT V FARESE
• 金额: --
• 依托单位: JAMES A. HALEY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8762424
• 关键词: 1-Phosphatidylinositol 3-Kinase; Accounting; Address; Adenoviruses; Adipocytes; Adipose tissue; Alleles; B-Lymphocytes; Binding Proteins; Carbohydrates; Cardiovascular Diseases; Cardiovascular system; Central obesity; Clinical; Defect; Development; Disease; Elements; Embryo; Enzymes; Fasting; Fatty acid glycerol esters; Gluconeogenesis; Glucose; Glucose Intolerance; Glycerol; Health; Hepatic; Homeostasis; Hyperglycemia; Hyperinsulinism; Hyperlipidemia; Impairment; Inflammatory; Insulin; Insulin Receptor; Insulin Resistance; Islets of Langerhans; Knock-out; Knockout Mice; Leptin; Lipids; Liver; Mediating; Medical center; Metabolic; Metabolic syndrome; Metabolism; Modeling; Mus; Muscle; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Pathogenesis; Pathway interactions; Patients; Phenotype; Phosphoenolpyruvate Carboxylase; Phosphotransferases; Population; Process; Production; Protein Kinase C Alpha; Protein Kinase C Inhibitor; Reporting; Rest; Role; Serum; Signal Transduction; Sterols; Testing; Thinness; Tissues; Veterans; adenoviral-mediated; age related; atypical protein kinase C; blood glucose regulation; cytokine; diabetic; drug development; feeding; glucose output; glucose production; glucose tolerance; glucose transport; glucose-6-phosphatase; hepatic gluconeogenesis; impaired glucose tolerance; improved; inhibitor/antagonist; insulin receptor substrate 1 protein; insulin sensitivity; insulin signaling; knockout gene; novel; prevent; protein kinase C lambda; receptor; receptor binding; recombinase

DESCRIPTION (provided by applicant): Insulin stimulates glucose transport in muscle and adipocytes, and lipid synthesis in liver by activating atypical protein kinase C (aPKC) and Akt (PKB). Muscle-specific knockout of one PKC-lambda allele (Het-Mlambda KO) diminishes glucose transport, thus causing impaired glucose tolerance, insulin resistance, abdominal obesity, hepatosteatosis, and hyperlipidemia, i.e., a "metabolic syndrome" (MS), and ultimately type 2 diabetes mellitus (T2DM). Hyperinsulinemia in Het-M KO mice inordinately activates hepatic sterol receptor element receptor binding protein-1c (SREBP-1c) and NF B, and resultant increases in lipid and cytokine production presumably contribute to insulin resistance, and this is probably abetted by recently observed increases in hepatic activities of conventional and novel PKCs (alpha,B2,epsilon,theta ) in older Het-Mlambda KO mice, We have also generated adipocyte (A)-specific PKC-lambda KO (Alambda KO) mice and glucose transport is diminished in isolated adipocytes. However, unlike Mlambda KO mice, Alambda -KO mice are lean and have normal glucose tolerance, normal serum levels of insulin and lipids, and clamp studies reveal increases in hepatic insulin sensitivity and suppression of hepatic glucose output, owing to decreased expression of phosphoenolpyruvate carboxykinase (PEPCK). We postulate that diminished glucose transport in Alambda -KO adipocytes limits glycerol-PO4 availability for fat synthesis, and resulting leanness, possibly via hypoleptinemia, downregulates hepatic PEPCK expression and thereby confers "metabolic protection". Liver-specific PKC-lambda KO (Llambda KO) also protects lipid and glucose homeostasis by diminishing activation of hepatic SREBP-1c and NF B, and by diminishing fasting-dependent expression of PEPCK and glucose-6-phosphatase (G6Pase). Thus, specific inhibition of hepatic aPKC by adenoviral-mediated expression of kinase-inactive aPKC, or our newly developed PKC-lambda inhibitors, diminishes insulin activation of SREBP-1c/NF B, and fasting expression of PEPCK/G6Pase, thereby markedly improving obesity, hyperlipidemia, hyperglycemia, insulin signaling in muscle, and insulin resistance in obese/T2DM mice. We have also generated mice with total body loss of one PKC-lambda allele (Het-TBlambda KO) and as expected glucose transport in muscle and adipose tissues is diminished; however, these mice unexpectedly have poor activation of the insulin receptor and Akt, as well as aPKC, in muscle, adipose and liver tissues. Despite these signaling defects, aside from mild glucose intolerance and hyperinsulinemia, Het-TBlambda KO mice do not develop MS or T2DM. We postulate that partial loss of hepatic PKC-lambda in Het-TB KO confers "metabolic protection" by diminishing activity/expression of SREBP-1c, NF B, PEPCK and G6Pase. In Specific Objective 1, to define mechanisms underlying leanness and metabolic protection in AlambdaKO mice, we will examine: lipogenic and lipolytic processes in adipocytes; factors that contribute to leanness; alterations in hepatic lipogenic, inflammatory and gluconeogenic pathways during high-fat feeding; and, the role of hypoleptinemia in diminishing hepatic gluconeogenesis. In Specific Objective 2, we will test the idea that the partial loss of hepatic PKC-lambda confers metabolic protection in Het-TB KO mice by replenishing hepatic aPKC. In Specific Objective 3, we will examine age-dependent alterations in activities of conventional and novel PKCs in tissues of Het-Mlambda KO mice and correlate these alterations with impairments in insulin signaling as these mice become progressively diabetic.

描述（由申请人提供）： 胰岛素通过激活非典型蛋白激酶C（APKC）和AKT（PKB）来刺激肌肉和脂肪细胞中的葡萄糖转运以及肝脏中的脂质合成。 Muscle-specific knockout of one PKC-lambda allele (Het-Mlambda KO) diminishes glucose transport, thus causing impaired glucose tolerance, insulin resistance, abdominal obesity, hepatosteatosis, and hyperlipidemia, i.e., a "metabolic syndrome" (MS), and ultimately type 2 diabetes mellitus (T2DM). Het-M KO小鼠中的高胰岛素血症非洲非胰岛素激活肝固醇受体元素受体结合蛋白1C（SREBP-1C）和NF B，并导致脂质和细胞因子产生的增加可能有助于胰岛素抵抗，最近在常规和新的肝素活性中增加了这种胰岛素的耐药性，这可能会增加。 （alpha，b2，epsilon，theta）在较老的het-mlambda ko小鼠中，我们还产生了脂肪细胞（A）特异性的PKC-LAMBDA KO（Alambda KO）小鼠，葡萄糖转运在分离的脂肪细胞中减小。然而，与mlambda ko小鼠不同，alambda -ko小鼠苗条并且具有正常的葡萄糖耐受性，正常的血清胰岛素和脂质水平，并且夹紧研究揭示了肝胰岛素敏感性和肝葡萄糖输出抑制的增加，因此由于磷酸烯醇丙烯酸甲酰基二甲酰基二碳酸酯酶（Pepck）的表达降低。我们假设在Alambda -KO脂肪细胞中葡萄糖转运减少，限制了甘油-PO4的脂肪合成可用性，并可能通过低肽血症通过低肽血症，从而降低了肝pepck的表达，从而使“代谢保护”上调节。肝脏特异性PKC-LAMBDA KO（LLAMBDA KO）还通过减少肝SREBP-1C和NF B的激活来保护脂质和葡萄糖稳态，并通过减少pepck和pepck和葡萄糖-6-磷酸酶（G6Pase）的禁食依赖性表达（G6Pase）。 Thus, specific inhibition of hepatic aPKC by adenoviral-mediated expression of kinase-inactive aPKC, or our newly developed PKC-lambda inhibitors, diminishes insulin activation of SREBP-1c/NF B, and fasting expression of PEPCK/G6Pase, thereby markedly improving obesity, hyperlipidemia, hyperglycemia, insulin signaling in肥胖/T2DM小鼠的肌肉和胰岛素抵抗。我们还产生了一个小鼠，其全身损失的一只PKC-Lambda等位基因（Het-Tblambda KO），并且肌肉和脂肪组织中预期的葡萄糖转运也减少了。然而，这些小鼠意外地在肌肉，脂肪和肝组织中，胰岛素受体和AKT以及APKC的激活差。尽管存在这些信号传导缺陷，除了轻度的葡萄糖不耐症和高胰岛素血症外，Het-Tblambda KO小鼠还不会发展MS或T2DM。我们假设HET-TB KO中肝PKC-LAMBDA的部分损失通过减少SREBP-1C，NF B，PEPCK和G6Pase的活性/表达来赋予“代谢保护”。在特定目标1中，要定义Alambdako小鼠瘦弱和代谢保护的机制，我们将检查：脂肪细胞中的脂肪生成和脂溶性过程；导致瘦身的因素；高脂进食过程中肝脂肪生成，炎症和糖原的途径的改变；并且，低肽血症在减少肝糖异生中的作用。在特定目标2中，我们将测试肝PKC-Lambda的部分损失通过补充肝APKC来赋予HET-TB KO小鼠中的代谢保护的想法。在特定目标3中，我们将检查HET-Mlambda KO小鼠组织中常规和新型PKC的活性的年龄依赖性改变，并将这些改变与胰岛素信号传导中的损害相关联，因为这些小鼠逐渐糖尿病。