Free Radical Mechanism in Obesity Potentiation of Environmental Hepatotoxicity

肥胖环境肝毒性增强中的自由基机制

• 批准号: 8532898
• 负责人: Saurabh Chatterjee
• 金额: $ 24.89万
• 依托单位: UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-17 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8532898
• 关键词: Autoimmune Process; CYP2E1 gene; Cell Death; Chemosensitization; Chronic; Development; Diet; Disinfection; Dose; Environment; Environmental Exposure; Enzyme Inhibitor Drugs; Enzyme Inhibitors; Enzymes; Exposure to; Fatty Liver; Free Radical Formation; Free Radicals; Generations; Granulocyte-Macrophage Colony-Stimulating Factor; Hepatotoxicity; In Vitro; Individual; Inflammation; Inflammatory; Instruction; Interferon Type II; Interferons; Isoenzymes; Knockout Mice; Lead; Leptin; Lipid Peroxidation; Macrophage Activation; Mus; NADPH Oxidase; Obese Mice; Obesity; Population; Proteins; Public Health; Research Project Grants; Risk; Risk Factors; Role; Steatohepatitis; System; Testing; Toxic Environmental Substances; Translations; Tumor Necrosis Factor-alpha; United States; adduct; dietary restriction; hepatotoxin; human TNF protein; in vivo; liver injury; neutralizing antibody; novel; oxidation; research study; response

Obesity associated Nonalcoriolic steatohepatitis (NASH), has become a growing public health concern with increased obesity population in the United States. Progression from steatosis (fatty liver) to steatohepatitis (fatty liver with inflammation) is thought to require a second hit. This second hit can be provided by environmental exposure to hepatotoxins that are reductively metaboiized to form reactive free radicals. Although direct exposure to high doses of environmental hepatotoxins is rare, low exposure from the environment is more com.mon. Low doses may be well tolerated by normal healthy individuals but can be potential risk factors for inflammatory liver injuries like steatohepatitis in obese persons. Thus the long term objective of this research project is to test the hypothesis that low hepatotoxin exposure from the environment can potentiate the risk of progression of steatohepatitis in obese mice. The hypothesis will be tested in three specific aims that include investigating the mechanism of free radical formation and post-translation oxidation adducts of proteins in obese mice in response to the disinfection byproduct (DBP) bromodichloromethane (BDCM). The specific aims will be achieved by using inhibitors of enzymes such as NADPH oxidase and the Cyp450 isozyme CYP2E1 and with knockout mice lacking each of these enzymes. All studies in obesity will be carried out in diet-induced obese (DIG) mice and compared to diet-restricted lean controls. In Aim 2, 1 shall examine how initial lipid peroxidation, interferon-gamma (IFN-y) and granulocyte macrophage colony stimulating factor (GMCSF) lead to activation of macrophages and contribute to the second wave of generation of free radical damage and TNF-alpha secretion following BDCM exposure. This aim will be achieved through experiments using both in vivo and in vitro systems, in aim 3, I shall investigate the role of the proinflammatory adipocytokine leptin in synergizing the effect of environmental hepatotoxins such as bromodichloromethane, a DBP, This aim will be achieved by investigating free radical-induced macrophage activation and cell death in Ieptin knockout mice and using neutralizing antibodies against Ieptin.

随着美国肥胖人口的增加，肥胖相关的非酒精性脂肪性肝炎（NASH）已成为一个日益关注的公共卫生问题。从脂肪变性（脂肪肝）到脂肪性肝炎（脂肪肝伴炎症）的进展被认为需要第二次治疗。这第二次打击可以通过环境暴露于肝毒素提供，肝毒素被还原性代谢形成活性自由基。虽然直接接触高剂量环境肝毒素的情况很少见，但从环境中接触低剂量肝毒素的情况更为常见。正常健康人可以很好地耐受低剂量，但可能是肥胖人群脂肪性肝炎等炎症性肝损伤的潜在危险因素。因此，本研究项目的长期目标是验证这样一种假设，即来自环境的低肝毒素暴露可以增加肥胖小鼠脂肪性肝炎进展的风险。这一假设将在三个具体目标中得到验证，包括研究肥胖小鼠对消毒副产物（DBP）溴二氯甲烷（BDCM）的反应中自由基形成和蛋白质翻译后氧化加合物的机制。具体目标将通过使用诸如NADPH氧化酶和Cyp450同工酶CYP2E1等酶的抑制剂以及缺乏这些酶的敲除小鼠来实现。所有关于肥胖的研究都将在饮食诱导肥胖（DIG）小鼠中进行，并与饮食限制的瘦肉对照组进行比较。在Aim 2中，我将研究初始脂质过氧化、干扰素- γ (IFN-y)和粒细胞巨噬细胞集落刺激因子（GMCSF）如何导致巨噬细胞活化，并促进BDCM暴露后自由基损伤和tnf - α分泌的第二波产生。这一目标将通过体内和体外系统的实验来实现，在目标3中，我将研究促炎脂肪细胞因子瘦素在协同环境肝毒素（如溴二氯甲烷，一种DBP）作用中的作用，这一目标将通过在Ieptin敲除小鼠中研究自由基诱导的巨噬细胞活化和细胞死亡以及使用针对Ieptin的中和抗体来实现。