ATP Binding Cassette Transporters in Health and Disease

摘要 代谢性和慢性肝病是美国的主要死亡原因之一。肝是中枢 它协调调节包括脂质在内的许多营养物质的新陈代谢。肝脏并不储存脂肪 肝脏中脂质的长期积累会导致不同的疾病.甘油三酯在人体内的积累 肝脏引起脂肪变性，可发展为非酒精性脂肪性肝炎(NASH)，两者都是非酒精性脂肪性肝炎的一部分 脂肪肝(NAFLD)谱系。病毒感染、酒精导致的胆汁酸在肝脏中的蓄积 使用或更严重的肝脏损伤会导致胆汁淤积。特异性肺炎的分子机制研究进展 在将促进疾病的途径安全地用于疾病预防之前，促进疾病的途径是必不可少的步骤。 我们的研究将进一步了解过氧化物酶体ABCD转运蛋白在肝脏中的作用。我们有 使用一种无偏见的系统生物学方法来确定在调节脂质代谢方面的新参与者 肝脏。通过这些方法，我们确定了过氧化体转运蛋白ABCD3是一种新的肝脏调节因子 脂类代谢。Abcd3−/−小鼠是部分致死性的，存活的动物失去abcd3改变了肝脏 脂类和导致肝脏肿大和胆汁酸显著减少。为了在体内研究ABCD3，我们 已经开发并验证了一种新的AAV-CRISPR策略，以仅在肝脏内干扰Abcd3，从而 美国将以时间方式干扰成年野生型小鼠的Abcd3，以确定导致 ABCD3缺失后观察到的缺陷。使用这些工具，我们发现成人肝脏ABCD3的急性丢失 小鼠足以概括胆汁中胆汁酸的显著减少。当喂食西方饮食(WD)时，损失 肝脏ABCD3导致肝脏脂质堆积以及血浆肝酶和胆汁酸升高，所有这些 纳什的特征。我们设计了两个具体的目标；在目标1中，我们将测试ABCD3的假设 缺乏会导致胆汁淤积和NASH。在目标2中，我们将确定ABCD3的特定底物并测试 认为过氧酶体脂质缺陷是NASH发生的致病因素和关键。我们的研究 证明ABCD3的缺失对人类是致命的，会导致胆汁淤积症和NASH 血脂水平升高。这些研究的完成将进一步加深对过氧化物酶体ABCD作用的理解 肝脏中的转运蛋白，并牵涉到过氧化脂质代谢作为一种重要的贡献。 NASH的发病机制。

ABSTRACT Metabolic and chronic liver diseases are among the leading causes of death in the US. The liver is a central hub that coordinately regulates the metabolism of many nutrients, including lipids. The liver does not store lipids in the long-term, and lipid accumulation in the liver results in different diseases. Triglyceride accumulation in the liver causes steatosis which can progress to non-alcoholic steatohepatitis (NASH), both part of the non-alcoholic fatty liver disease (NAFLD) spectrum. Accumulation of bile acids in the liver because of viral infections, alcohol use or more advanced liver damage causes cholestasis. Identification of the molecular mechanisms of specific disease-promoting pathways is an essential step before pathways can be safely targeted for disease prevention. Our studies will further the understanding of the role of peroxisomal ABCD transporters in the liver. We have used an unbiased systems biology approach to identify new players in the regulation of lipid metabolism in the liver. Through these methods, we identified the peroxisomal transporter ABCD3 as a novel regulator of hepatic lipid metabolism. Abcd3−/− mice are partially lethal and loss of ABCD3 in surviving animals alters the hepatic lipidome and results in hepatomegaly and profoundly reduced biliary bile acids. To study ABCD3 in vivo, we have developed and validated a novel AAV-CRISPR strategy to disrupt Abcd3 exclusively in the liver, allowing us to disrupt Abcd3 in adult wild-type mice in a temporal fashion to determine the sequelae of events leading to the defects observed after loss of ABCD3. Using these tools, we show that acute loss of hepatic ABCD3 in adult mice is sufficient to recapitulate the dramatic reduction in biliary bile acids. When fed a Western diet (WD), loss of hepatic ABCD3 results in liver lipid accumulation as well as elevated plasma liver enzymes and bile acids, all hallmarks of NASH. We have designed two specific aims; in Aim 1 we will test the hypothesis that ABCD3 deficiency results in cholestasis and NASH. In Aim 2, we will identify specific substrates for ABCD3 and test the hypothesis that peroxisomal lipid defects are pathogenic and key for the development of NASH. Our studies demonstrate that loss of ABCD3, which is lethal in humans, results in cholestasis and NASH in a setting of elevated lipid levels. Completion of these studies will further the understanding of the role of peroxisomal ABCD transporters in the liver, and implicate peroxisomal lipid metabolism as an important contributor in the pathogenesis of NASH.