Nicotine and Alcoholic Liver Disease

 描述(申请人提供)：酗酒是一个严重的全球健康问题。长期饮酒可导致酒精性肝病，范围从脂肪变性(脂肪肝)到脂肪性肝炎、纤维化和肝硬变。大约90%的酗酒者会患上酒精性脂肪肝(AFL)，这是酒精性肝病的一种发病。最近，我们发现慢性酒精摄入诱导了细胞色素P450 2A5的表达，而酒精中毒患者体内的细胞色素P450 2A6水平升高。细胞色素P450 2A5/6是一种主要的尼古丁代谢酶。酒精和烟草经常被滥用，烟草烟雾会增加酒精性脂肪肝。我们的初步结果表明，尼古丁可以增加AFL和高甘油三酯血症(HTG)，这在WT小鼠中观察到，但在cyp2a5-/-小鼠中没有观察到。在AIM 1中，我们将通过AAV8将CYP2A5重新引入cyp2a5/-小鼠，以确认CYP2A5在尼古丁增强的AFL和HTG中的重要作用，并应用可替宁和抗氧化剂来研究CYP2A5产生的尼古丁代谢物和氧化应激在尼古丁增强的AFL和HTG中的作用。FGF21是一种新的代谢调节因子，在肝脏中高表达。肝脏FGF21受PPARα调控。在cyp2a5-/-小鼠肝脏中观察到PPARα-FGF21的结构性升高。重组人成纤维细胞生长因子21可阻断乙醇诱导的α-/-小鼠酒精性高血糖，但在WT小鼠中未观察到。FGF21通过主要表达于脂肪组织的成纤维细胞生长因子受体1(FR1)来调节细胞活性。肝脏FGF21可以释放到血液中，以内分泌方式发挥作用。FGF21可刺激脂肪细胞分泌脂联素，进而作用于肝脏，改善AFL。在目标2中，我们将通过应用PPARα和FGF21、肝脏特异的FGF21基因敲除小鼠和PPARα特异性激动剂WY-14,643来研究PPARα-FGF21轴在尼古丁增强的AFL和HTG中的作用。在AIM 3脂肪特异性受体基因敲除小鼠和脂联素基因敲除小鼠中，将评估PPARα调控的肝脏FGF21是否通过脂联素，即α-FGF21-脂联素在脂肪组织中发挥作用，以调节尼古丁增加的AFL和HTG。最后，应用脂联素和CYP2A5双基因敲除小鼠来研究脂联素在观察尼古丁增强的AFL和HTG中的作用，而在cyp2a5-/-小鼠中观察不到。

 DESCRIPTION (provided by applicant): Alcohol abuse is a significant global health problem. Chronic alcohol drinking can induce alcoholic liver disease, which ranges from steatosis (fatty liver) to steatohepatitis, fibrosis and cirrhosis. About 90% of heavy alcohol drinkers develop alcoholic fatty livers (AFL), an onset of alcoholic liver disease. Recently, we found that CYP2A5 is induced by chronic ethanol feeding and CYP2A6 is elevated in alcoholic patients. CYP2A5/6 is a major nicotine metabolic enzyme. Alcohol and tobacco are frequently co-abused and tobacco smoke can increase alcoholic fatty liver. Our preliminary results indicate that nicotine can enhance AFL and hypertriglyceridemia (HTG), which was observed in WT mice but not in cyp2a5-/- mice. In AIM 1 we will reintroduce CYP2A5 back to cyp2a5-/- mice via AAV8 to confirm the essential role of CYP2A5 in the nicotine-enhanced AFL and HTG and apply cotinine and antioxidants to examine the role of CYP2A5-produced nicotine metabolites and oxidative stress in the nicotine-enhanced AFL and HTG. FGF21 is a novel metabolic regulator highly expressed in liver. Liver FGF21 is regulated by PPARα. Constitutive elevation of PPARα-FGF21 in liver was observed in cyp2a5-/- mice. Ethanol-induced HTG, which was observed in pparα-/- mice but not in WT mice, can be blocked by rFGF21. FGF21 modulates cellular activity through FGF receptor 1 (FR1), which is mainly expressed in adipose tissues. Liver FGF21 can be released into blood to act in an endocrine manner. FGF21 can stimulate adipocytes to secret adiponectin, which in turn acts on the liver to ameliorate AFL. In AIM 2 we will examine the role of a PPARα-FGF21 axis in the nicotine- enhanced AFL and HTG by applying PPARα and FGF21, liver-specific FGF21 knockout mice and PPARα specific agonist WY-14,643. In AIM 3 adipose-specific FR1 knockout mice and adiponectin knockout mice will be applied to evaluate if PPARα-regulated liver FGF21 exerts its action in adipose tissue through adiponectin i.e. the PPARα-FGF21-adiponectin to regulate nicotine-enhanced AFL and HTG. At last, adiponectin and CYP2A5 double knockout mice will be applied to investigate the role of adiponectin in the observation that nicotine-enhanced AFL and HTG was observed in WT mice but not in cyp2a5-/- mice.