Immunologic Mechanisms of Alcoholic Liver Disease

酒精性肝病的免疫学机制

• 批准号: 8746472
• 负责人: bin gao
• 金额: $ 88.82万
• 依托单位: NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8746472
• 关键词: Acetaldehyde; Acute; Adrenal Cortex Hormones; Affect; Agreement; Alanine Transaminase; Alcohol consumption; Alcoholic Hepatitis; Alcoholic Liver Diseases; Asians; Attenuated; Autoimmune Hepatitis; Blood alcohol level measurement; Carbon Tetrachloride; Cells; Chronic; Cirrhosis; Concanavalin A; Diet; Disease Progression; Endocannabinoids; Enzymes; Ethanol; Ethanol Metabolism; Exhibits; Fatty Liver; Fibrosis; Galactosylceramides; Genes; Glucocorticoid Receptor; Goals; Hepatic; Hepatitis; Hepatocellular Damage; Human; Immunologics; In Vitro; Individual; Inflammation; Inflammatory; Inflammatory Response; Interleukin-6; Kupffer Cells; Laboratories; Liquid substance; Liver; Liver Fibrosis; Liver Regeneration; Liver diseases; Malondialdehyde; Mediating; Modeling; Mus; National Institute on Alcohol Abuse and Alcoholism; Neutrophil Infiltration; Oral; Organ; Pathogenesis; Patients; Primary carcinoma of the liver cells; Production; Reporting; Resistance; Role; Serum; Signaling Molecule; Slice; Staging; Stat3 protein; Steatohepatitis; Steroid therapy; Steroids; System; Therapeutic; Wild Type Mouse; acetaldehyde dehydrogenase; adduct; aldehyde dehydrogenases; chronic alcohol ingestion; chronic liver disease; feeding; hepatotoxin; in vivo; interleukin-22; liver inflammation; liver injury; liver repair; macrophage; mouse model; neutrophil; new therapeutic target; paracrine; prednisolone; prevent; problem drinker; regenerative

Our laboratory has been actively studying the pathogenesis of alcoholic liver disease, focusing on the role of acetaldehyde dehydrogenase 2 (ALDH2) and prednisolone in alcoholic liver injury, and we have also developed a mouse model of chronic plus binge ethanol feeding model, which represents early stages of human alcoholic steatohepatitis. Chronic alcohol consumption is a leading cause of chronic liver disease worldwide, leading to cirrhosis and hepatocellular carcinoma. Currently, the most widely used model for alcoholic liver injury is ad libitum feeding with the Lieber-DeCarli liquid diet containing ethanol for 4-6 weeks; however, this model, without the addition of a secondary insult, only induces mild steatosis, slight elevation of serum alanine transaminase (ALT) and little or no inflammation. During this reporting period, we developed a simple mouse model of alcoholic liver injury by chronic ethanol feeding (10-d ad libitum oral feeding with the Lieber-DeCarli ethanol liquid diet) plus a single binge ethanol feeding. This chronic-plus-single-binge ethanol feeding synergistically induces liver injury, inflammation and fatty liver, which mimics acute-on-chronic alcoholic liver injury in patients. Chronic-binge ethanol feeding leads to high blood alcohol levels; thus, this simple model will be very useful for the study of alcoholic liver disease (ALD) and of other organs damaged by alcohol consumption. Aldehyde dehydrogenase 2 (ALDH2) is the major enzyme that metabolizes acetaldehyde produced from alcohol metabolism. Approximately 40 to 50% of East Asians carry an inactive ALDH2 gene and exhibit acetaldehyde accumulation after alcohol consumption. However, the role of ALDH2 deficiency in the pathogenesis of alcoholic liver injury remains obscure. During this reporting period, we have used wild-type (WT) and ALDH2-/- mice to examine the roles of ALDH2 in alcoholic liver injury and fibrosis by using ethanol feeding and/or carbon tetrachloride (CCl4) treatment. Compared with WT mice, ethanol-fed ALDH2-/- mice had higher levels of malondialdehyde and acetaldehyde (MAA) adduct and greater hepatic inflammation, with higher hepatic interleukin-6 (IL-6) expression but surprisingly lower levels of steatosis and serum ALT. Higher IL-6 levels were also detected in ethanol-treated precision-cut-liver slices from ALDH2-/- mice and in Kupffer cells isolated from ethanol-fed ALDH2-/- mice than those levels in WT mice. In vitro incubation with MAA enhanced the LPS-mediated stimulation of IL-6 production in Kupffer cells. In agreement with these findings, hepatic activation of the major IL-6 downstream signaling molecule signal transducer and activator of transcription 3 (STAT3) was higher in ethanol-fed ALDH2-/- mice than in WT mice. An additional deletion of hepatic STAT3 resulted in increased steatosis and hepatocellular damage in ALDH2-/- mice. Finally, ethanol-fed ALDH2-/- mice were more prone to CCl4-induced liver inflammation and fibrosis than ethanol-fed WT mice. CONCLUSIONS: ALDH2-/- mice are resistant to ethanol-induced steatosis but prone to inflammation and fibrosis via MAA-mediated paracrine activation of IL-6 in Kupffer cells. These findings suggest that ALDH2-deficient individuals may be resistant to steatosis, but are prone to liver inflammation and fibrosis following alcohol consumption. Prednisolone is a corticosteroid that has been used to treat inflammatory liver diseases, such as autoimmune hepatitis and alcoholic hepatitis. However, the results have been controversial, and how prednisolone affects liver disease progression remains unknown. During this reporting period, we examined the effect of prednisolone treatment on several models of liver injury, including T/NKT cell hepatitis induced by concanavalin A (Con A) and -galactosylceramide (-GalCer), and hepatotoxin-mediated hepatitis induced by carbon tetrachloride (CCl4). Prednisolone administration attenuated ConA- and -GalCer-induced hepatitis and systemic inflammatory responses. Treating mice with prednisolone also suppressed inflammatory responses in a model of hepatotoxin (CCl4)-induced hepatitis, but surprisingly exacerbated liver injury and delayed liver repair. Immunohistochemical and flow cytometric analyses demonstrated that prednisolone treatment inhibited hepatic macrophage and neutrophil infiltration in CCl4-induced hepatitis and suppressed their phagocytic activities in vivo and in vitro. Macrophage and/or neutrophil depletion aggravated CCl4-induced liver injury and impeded liver regeneration. Finally, conditional disruption of glucocorticoid receptor in macrophages and neutrophils abolished prednisolone-mediated exacerbation of hepatotoxin-induced liver injury. Conclusion: Prednisolone treatment prevents T/NKT cell hepatitis but exacerbates hepatotoxin-induced liver injury by inhibiting macrophage- and neutrophil-mediated phagocytic and regenerative functions. These findings may not only increase our understanding of the steroid treatment mechanism but also help us to better manage steroid therapy in liver diseases. In addition, we are also collaborating with Drs. George Kunos and Pal Pacher from NIAAA to investigate the role of the endocannabinoid system in alcoholic liver disease.

我们的实验室一直在积极研究酒精性肝病的发病机理，重点是乙醛脱氢酶2（ALDH2）和泼尼松龙在酒精性肝损伤中的作用，我们还开发了慢性小鼠模型的小鼠模型，代表了人类酒精锻炼的早期阶段。 慢性饮酒是全球慢性肝病的主要原因，导致肝硬化和肝细胞癌。目前，最广泛的酒精肝损伤模型是用含有乙醇的lieber-decarli液体饮食的多次进食4-6周。但是，该模型在不增加继发性损伤的情况下只会诱导轻度的脂肪变性，血清丙氨酸转氨酶（ALT）的轻微升高，几乎没有或没有炎症。在此报告期间，我们通过慢性乙醇喂养（用Lieber-Decarli乙醇液体饮食）和单个暴饮暴食乙醇喂养开发了一种简单的小鼠肝损伤小鼠模型。这种慢性 - 伴侣乙醇的喂养可以协同诱导肝损伤，炎症和脂肪肝，这模仿了患者的急性智力酒精肝损伤。慢性饮食乙醇喂养可导致高血液酒精水平；因此，这个简单的模型对于研究酒精性肝病（ALD）和其他因饮酒而损害的器官的研究将非常有用。 醛脱氢酶2（ALDH2）是代谢通过酒精代谢产生的乙醛的主要酶。大约40％至50％的东亚携带不活跃的ALDH2基因，并在饮酒后表现出乙醛积累。然而，AldH2缺乏在酒精性肝损伤发病机理中的作用仍然晦涩难懂。在此报告期间，我们使用野生型（WT）和Aldh2 - / - 小鼠来检查Aldh2通过使用乙醇喂食和/或四氯化碳（CCL4）处理来检查ALDH2在酒精肝损伤和纤维化中的作用。与WT小鼠相比，乙醇喂养的ALDH2 - / - 小鼠具有更高水平的丙二醛和乙醛加合物（MAA）加合物和较大的肝发炎，肝介体介体6（IL-6）表达较高，但出乎意料地较低的steatosis和Sateatosis和Serm Alt水平较低。在乙醇处理的精确切割切片中还检测到来自aldh2 - / - 小鼠的精确切割切片，以及从乙醇喂养的Aldh2 - / - 小鼠中分离出的kupffer细胞中的IL-6水平。与MAA的体外孵育增强了LPS介导的Kupffer细胞中IL-6产生的刺激。与这些发现一致，在乙醇喂养的ALDH2 - / - 小鼠中，主要IL-6下游信号分子信号传感器和转录3（STAT3）的激活因素高于WT小鼠中的肝激活。肝Stat3的另一种缺失导致脂肪变性和肝细胞损伤增加了ALDH2 - / - 小鼠。最后，与乙醇喂养的WT小鼠相比，乙醇喂养的ALDH2 - / - 小鼠更容易发生CCL4诱导的肝脏炎症和纤维化。结论：ALDH2 - / - 小鼠对乙醇诱导的脂肪变性有抵抗力，但易于通过MAA介导的kupffer细胞中IL-6的旁分泌激活炎症和纤维化。这些发现表明，ALDH2缺陷的个体可能对脂肪变性具有抵抗力，但饮酒后容易发生肝炎和纤维化。 泼尼松龙是一种皮质类固醇，已用于治疗炎性肝疾病，例如自身免疫性肝炎和酒精性肝炎。但是，结果一直存在争议，泼尼松龙如何影响肝病进展仍然未知。在此报告期间，我们检查了泼尼松酮治疗对几种肝损伤模型的影响，包括浓蛋白乳蛋白酶A（CON A）（CON A）和-Actosylcerylceramide（-galcer）和肝毒素介导的肝炎诱导的T/NKT细胞肝炎。泼尼松龙的给药减弱了康纳氏菌和galcer诱导的肝炎和全身性炎症反应。用泼尼松龙治疗小鼠在肝毒素（CCL4）诱导的肝炎模型中还抑制了炎症反应，但出乎意料地加剧了肝损伤并延迟了肝脏修复。免疫组织化学和流式细胞术分析表明，泼尼松龙治疗在CCL4诱导的肝炎中抑制肝巨噬细胞和中性粒细胞浸润，并在体内和体外抑制其吞噬活性。巨噬细胞和/或中性粒细胞耗尽加剧CCL4诱导的肝损伤和阻碍肝脏再生。最后，巨噬细胞和中性粒细胞中糖皮质激素受体的有条件破坏废除了泼尼松龙介导的肝毒素诱导的肝损伤的加重。结论：泼尼松龙治疗可防止T/NKT细胞肝炎，但通过抑制巨噬细胞和中性粒细胞介导的吞噬和再生功能，加剧了肝毒素诱导的肝损伤。这些发现不仅可以增加我们对类固醇治疗机制的理解，而且还可以帮助我们更好地管理肝病中的类固醇治疗。 此外，我们还与DRS合作。 NIAAA的乔治·库诺斯（George Kunos）和帕尔·帕切（Pal Pacher）研究内源性大麻素系统在酒精性肝病中的作用。