Inflammation, miRNA and autophagy in diabetes

糖尿病中的炎症、miRNA 和自噬

基本信息

批准号：
8711702
负责人：
Paras Kumar Mishra
金额：
$ 37.5万
依托单位：
UNIVERSITY OF NEBRASKA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-01-07 至 2018-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8711702
关键词：
Ablation Address Antioxidants Attenuated Autophagocytosis Binding Sites Biological Assay Biological Markers Blood Breeding C3H/HeJ Mouse Cardiac Cardiac Myocytes Cardiomyopathies Cardiovascular Diseases Clinical Research Confocal Microscopy Diabetes Mellitus Dose Down-Regulation Endopeptidases Enhancers Fibrosis Functional disorder Gel Gelatin Zymography Gelatinase B Gene Targeting Genes Genetic Transcription Glucose Goals Heart Heart Hypertrophy Heart failure Hybrids Hydrogen Peroxide Hyperglycemia Impairment In Situ Inflammation Inhibition of Matrix Metalloproteinases Pathway Lead Luciferases Measures Mediating MicroRNAs Molecular Morbidity - disease rate Mus Muscle Fibers Myocardium Myosin ATPase Nuclear Oxidants Oxidative Stress Patients Plasmids Play Proteins Pump Regulation Reporter Reporter Genes Resistance Role Skeletal Muscle Streptozocin Subfamily lentivirinae Testing Transfection Untranslated Regions Up-Regulation Western Blotting attenuation diabetic diabetic cardiomyopathy glucose uptake improved mortality tempol therapeutic target

项目摘要

Project Summary: A major cause of diabetes is impairment of glucose uptake by skeletal muscle that causes pumping of extra glucose into blood leading to hyperglycemia. Clinical studies revealed that diabetes causes cardiomyopathy and the chances of heart failure increases if the patient has diabetes. One of the mechanisms of cardiac dysfunction associated with diabetes is oxidative stress that activates latent matrix metalloproteinase-9 (MMP9), which in turn induces fibrosis and contractile dysfunction. However, the specific mechanisms for how oxidative stress activates MMP9, which leads to contractile dysfunction, have not been investigated. Our preliminary studies on HL1 cardiomyocytes suggest that inhibition of miR-133 induces MMP9 and over expression of miR-133 inhibits MMP9. The luciferase reporter assay revealed that miR-133 targets MMP9. Interestingly, glucose mediated induction of MMP9 is abrogated by miR-133. In the heart of diabetic Akita mice, myosin enhancer factor 2c (Mef2c- an inducer of miR-133) is alleviated, miR-133 is down regulated and MMP9 is robust. These results lead us to hypothesize that oxidative stress inhibits Mef2c causing attenuation of miR-133 that induces MMP9 leading to contractile dysfunction in diabetes. To address the hypothesis, we formulated three specific aims: Aim#1: To determine whether the miR-133 directly or indirectly inhibits the activation of MMP9. Hypothesis: MiR-133 directly inhibits MMP9 by targeting its 3/ UTR. It also indirectly inhibits MMP9 by inducing miR-466 and abrogating miR-705. Aim# 2: To determine whether the oxidative stress inhibits Mef2c causing attenuation of miR-133 in diabetes. Hypothesis: The oxidative stress inhibits Mef2c that causes attenuation of miR-133 in diabetes. Aim # 3: To determine whether the over-expression of miR-133 or Mef2c will inhibit MMP9 that in turn improve glucose uptake in skeletal muscle and ameliorates contractile dysfunction in diabetes. Hypothesis: The over expression of miR-133 and Mef2c inhibits MMP9 that enhances glucose uptake by skeletal muscle and mitigates contractile dysfunction of cardiomyocytes in diabetes. Our proposal unravels a new mechanism of regulation of MMP9 by miR-133. It also provides a new concept that miRNA inhibits a gene not only by directly targeting it rather it also induces / inhibits other miRNAs that indirectly influences the target gene. At translational level, the proposal will provide concrete evidence that over expression of miR-133 or ablation of MMP9 can ameliorate diabetic cardiomyopathy.

项目概要：糖尿病的一个主要原因是骨骼肌对葡萄糖的摄取受损，从而导致将额外的葡萄糖泵入血液导致高血糖。临床研究表明糖尿病会导致心肌病，如果患者有以下情况，则心力衰竭的几率会增加糖尿病。与糖尿病相关的心功能障碍的机制之一是氧化激活潜在基质金属蛋白酶 9 (MMP9) 的应激，进而诱导纤维化和收缩功能障碍。然而，氧化应激激活的具体机制导致收缩功能障碍的 MMP9 尚未得到研究。我们的初步对 HL1 心肌细胞的研究表明，抑制 miR-133 会诱导 MMP9 及以上 miR-133 的表达抑制 MMP9。荧光素酶报告基因检测显示 miR-133 靶向 MMP9。有趣的是，葡萄糖介导的 MMP9 诱导被 miR-133 消除。在糖尿病秋田小鼠的心脏中，肌球蛋白增强因子 2c（Mef2c - miR-133 的诱导剂）是缓解后，miR-133 下调且 MMP9 稳定。这些结果使我们推测氧化应激抑制 Mef2c，导致诱导 MMP9 的 miR-133 减弱导致糖尿病的收缩功能障碍。为了解决这个假设，我们制定了三个具体目标：目标#1：确定 miR-133 是否直接或间接抑制基质金属蛋白酶9。假设：MiR-133 通过靶向 MMP9 的 3/ UTR 直接抑制 MMP9。也间接抑制了 MMP9 通过诱导 miR-466 并消除 miR-705。目标# 2：确定氧化应激是否会抑制 Mef2c，从而导致 Mef2c 减弱 miR-133 在糖尿病中的作用。假设：氧化应激抑制 Mef2c，导致糖尿病中 miR-133 减弱。目标#3：确定 miR-133 或 Mef2c 的过表达是否会抑制 MMP9 进而改善骨骼肌的葡萄糖摄取并改善收缩糖尿病的功能障碍。假设：miR-133 和 Mef2c 的过度表达会抑制 MMP9，从而增强血糖骨骼肌摄取并减轻糖尿病心肌细胞的收缩功能障碍。我们的提议揭示了 miR-133 调节 MMP9 的新机制。它还提供了一个新概念，即 miRNA 不仅通过直接靶向基因来抑制基因，而且还通过基因本身来抑制基因诱导/抑制其他间接影响靶基因的 miRNA。在翻译层面上，该提案将提供具体证据，证明 miR-133 的过度表达或 miR-133 的消融 MMP9可以改善糖尿病心肌病。