YAP signaling in the pathogenesis of NAFLD in people living with HIV

项目总结/摘要 自从采用有效的联合抗逆转录病毒疗法（cART）以来， 从一种致命的疾病转变成一种慢性疾病肝病已成为非- 艾滋病毒感染者与艾滋病有关的死亡。非酒精性脂肪肝（NAFLD）是目前 慢性肝病的一种形式，大约有30%的成年人患病艾滋病毒携带者患病率很高， NAFLD的发病率高达53%，不仅与非酒精性炎症的发生频率较高有关， 脂肪性肝炎（NASH），但也加速肝纤维化进展。此外，在NAFLD/HIV中， 与HIV（-）NAFLD相比，进行性NASH和纤维化的负担不成比例。虽然最近的研究 已经复制了PLWH/NAFLD中所见的加速纤维化进展，精确的机制仍然存在。 定义不好。我们和其他人在证明艾滋病毒本身诱导一个促纤维化程序方面处于领先地位 通过多种途径进入肝脏。Hippo信号通路通过以下途径控制细胞增殖和纤维化 雅普转录共激活因子通过结合TEAD、SMAD 1/2/3和 其他网站.我们最近的研究表明，在NAFLD患者中，YAP相关基因表达增加， 纤维化和小鼠NASH模型。我们还观察到， 肝细胞特异性雅普敲除小鼠喂食NASH饮食。我们还发现HIV诱导雅普激活 在肝细胞和巨噬细胞中通过LPA/PI 3 K和AKT途径。因此，HIV和NAFLD可能 在雅普活化水平上协同作用，导致纤维化和肝损伤。肝脏和单核细胞- 衍生的巨噬细胞，由HIV感染失调，并在肝损伤过程中极化，可能有助于 NAFLD和HIV相关肝病。研究已经观察到， PLWH和其他人将雅普激活与巨噬细胞浸润联系起来。然而，全面研究 关键细胞类型（肝细胞、巨噬细胞和HSC）中雅普激活的体外和体内效应 导致PLWH纤维化的基因缺乏。我们假设HIV和NAFLD发挥独立和叠加作用， 对巨噬细胞和肝细胞群中雅普活化的影响，进而加速肝纤维化 通过其对HSC的作用进展。在这个提议中，使用新的共培养试验，离体肝组织， 和人源化小鼠模型，并结合肝脏发病机制和HIV病毒学/发病机制的努力， 我们将：（1）确定雅普信号转导对巨噬细胞极化、肝细胞和肝细胞的贡献。 HIV/NAFLD中星状细胞（HSC）活化; (2)评估cART方案对巨噬细胞、肝细胞 以及HIV/NAFLD模型中HSC表型和雅普活化。（3）确定雅普的作用 抑制HIV/NAFLD中的纤维形成。详细了解上下游监管机构 雅普在NAFLD/HIV中的作用可能会发现新的NAFLD抗纤维化策略， PLWH中普遍存在进行性肝病。 .

Project Summary/Abstract Since the introduction of effective combination antiretroviral therapy (cART), HIV infection has been converted from a fatal disease into a chronic condition. Liver disease has emerged as the second leading cause of non- AIDS related death in persons living with HIV (PLWH). Nonalcoholic fatty liver disease (NAFLD) is the leading form of chronic liver disease in the U.S., afflicting approximately 30% of adults. PLWH have a high prevalence of NAFLD with rates as high as 53%, associated with not only higher frequency of the inflammatory non-alcoholic steatohepatitis (NASH) but also accelerated liver fibrosis progression. Moreover, in NAFLD/HIV, there is a disproportionate burden of progressive NASH and fibrosis compared with HIV(-) NAFLD. While recent studies have replicated the accelerated fibrosis progression seen in PLWH/NAFLD, the precise mechanisms remain poorly defined. We and others have led the field in demonstrating that HIV itself induces a profibrogenic program in the liver via several pathways. The Hippo signaling pathway controls cell proliferation and fibrogenesis through YAP transcriptional co-activators that regulate more than 400 genes through binding to TEAD, SMAD1/2/3 and other sites. Our recent work has shown increases in YAP-related gene expression among NAFLD patients with fibrosis and in mouse NASH models. We also observed a significant reduction in fibrosis-related parameters in hepatocyte-specific YAP knockout mice fed a NASH diet. We have also shown that HIV induces YAP activation in hepatocytes and macrophages via the LPA/PI3K and AKT pathways. Therefore, HIV and NAFLD likely cooperate at the level of YAP activation to contribute to fibrogenesis and liver damage. Hepatic and monocyte- derived macrophages, dysregulated by HIV infection and polarized during liver injury, are likely to contribute to NAFLD and HIV-related liver disease. Studies have observed increased macrophage content in the livers of PLWH and others have linked YAP activation to macrophage infiltration. However, comprehensive studies of the in vitro and in vivo effects of YAP activation among the key cell types (hepatocytes, macrophages, and HSCs) that drive fibrogenesis in PLWH are lacking. We hypothesize that HIV and NAFLD exert independent and additive effects on YAP activation in both macrophage and hepatocyte populations that in turn accelerate hepatic fibrosis progression through their action on HSCs. In this proposal, using novel coculture assays, ex vivo liver tissue, and a humanized mouse model and combining the efforts of liver pathogenesis and HIV virology/pathogenesis experts, we will: (1) define the contribution of YAP signaling to macrophage polarization, hepatocyte and hepatic stellate cell (HSC) activation in HIV/NAFLD.; (2) assess the effect of cART regimens on macrophage, hepatocyte and HSC phenotypes and YAP activation in models of HIV/NAFLD.; and (3) determine the effects of YAP inhibition on fibrogenesis in HIV/NAFLD. A detailed understanding of the upstream and downstream regulators of YAP in NAFLD/HIV is likely to uncover novel antifibrotic strategies for NAFLD that could block this highly prevalent progressive liver disease in PLWH. .