HIV-Associated Macrophage Alterations and Progressive Liver Disease

 描述(由申请人提供)： 艾滋病毒的混合感染加速了丙型肝炎病毒和乙肝病毒相关的肝病的进展，是一个重大的公共卫生问题。慢性炎症是慢性病毒性肝炎的标志，其特点是炎症细胞群的渗透，包括激活的巨噬细胞，这也是艾滋病毒的重要宿主。活化的肝巨噬细胞两极分化为M1/促炎或M2/促纤维化表型，可激活肝星状细胞，导致纤维化。循环中的可溶性CD163(SCD163)是M2标志物，与慢性丙型肝炎和乙肝的纤维化密切相关。重要的是，在艾滋病毒感染中也观察到高水平的sCD163。我们的初步数据显示，与单独感染艾滋病毒或丙型肝炎病毒相比，艾滋病毒/丙型肝炎合并感染患者的sCD163水平显著增加，并且sCD163水平与肝纤维化分期显著相关。我们还观察到，成功的抗逆转录病毒治疗显著降低了艾滋病毒/丙型肝炎病毒重叠感染患者的sCD163水平。我们还发现，在体外，艾滋病毒和丙型肝炎病毒共同诱导M2表型。我们假设，HIV直接和间接地促进了促纤维化的M2巨噬细胞的扩张，进而在病毒性肝炎的背景下加剧了肝纤维化。最近有报道称，表达表皮生长因子受体(EGFR)的巨噬细胞通过IL-6依赖机制在促进肝细胞癌中发挥重要作用。由于IL-6可以诱导M2极化，而HIV被证明可以增强感染细胞中的EGFR信号，我们进一步假设EGF信号介导了HIV对促纤维化状态的形成。我们建议通过以下目标进一步探索这些假说：(1)确定患有和不患有慢性病毒性肝病的患者中HIV感染与M2标志物的关联。使用慢性丙型肝炎和乙肝患者的肝组织，我们将评估每种情况是否与HIV合并感染的肝内M2表型增强有关。我们还将通过评估无肝病证据的HIV单一感染者的肝组织，并与正常肝组织进行比较，来评估HIV单一感染是否与M2肝谱相关。(2)进行机制研究，其目的是明确HIV如何促进纤维前巨噬细胞极化的扩张。我们将使用RNA-Seq专门评估HIV对肝巨噬细胞的影响，并将通过进行抑制剂研究来评估EGFR信号对HIV对巨噬细胞种群影响的贡献。我们还将使用星状细胞共培养评估HIV对纤维化形成的促进作用。(3)体内外评价HIV抗逆转录病毒抑制对肝巨噬细胞的作用。后一项研究将使用接受抗逆转录病毒治疗的艾滋病毒/丙型肝炎混合感染者的肝脏细针抽吸物进行。我们将检验这一假设，即成功的HIV抑制部分但不能完全逆转HIV对促纤维化巨噬细胞表型改变的影响。这些研究将阐明巨噬细胞在HIV相关性肝纤维化进展中的作用。

 DESCRIPTION (provided by applicant): HIV co-infection accelerates HCV- and HBV-related liver disease progression and represents a major public health problem. Chronic inflammation, the hallmark of chronic viral hepatitis, is characterized by infiltration of inflammatory cell populations, including activated macrophages, which are also important reservoirs for HIV. Activated hepatic macrophages polarize into M1/pro-inflammatory or M2/profibrotic phenotypes that can activate hepatic stellate cells, leading to fibrosis. Circulating levels of soluble CD163 (sCD163), a characteristic M2 marker, have been strongly associated with fibrosis in chronic HCV and HBV. Importantly, high levels of sCD163 are also observed in HIV infection. Our preliminary data demonstrate significantly greater increase of sCD163 in HIV/HCV co-infection compared to HIV or HCV alone and that sCD163 levels significantly correlate with liver fibrosis stage. We also observed that successful anti-retroviral therapy in HIV/HCV coinfection significantly decreased sCD163 levels. We have also shown that HIV and HCV together cooperatively induce the M2 phenotype in vitro. We hypothesize that HIV directly and indirectly contributes to the expansion of profibrotic M2 macrophages, which in turn exacerbate liver fibrosis in the setting of viral hepatitis. Intriguingl, macrophages expressing epidermal growth factor receptor (EGFR) have been recently reported to play an essential role in promoting hepatocellular carcinoma via IL-6 dependent mechanisms. Since IL-6 can induce M2 polarization and HIV has been shown to enhance EGFR signaling in infected cells, we further hypothesize that EGF signaling mediates HIV's contribution to generation of the profibrogenic state. We propose to further explore these hypotheses through the following aims: (1) Determine the association of HIV infection with M2 markers in patients with and without chronic viral liver disease. Using liver tissue from patients with chronic HCV and HBV, we will assess whether each condition is associated with enhanced intrahepatic M2 phenotype in HIV coinfection. We will also assess whether HIV monoinfection is associated with the M2 hepatic profile by evaluating liver tissue from HIV monoinfected persons without evidence of liver disease and comparing to normal liver tissue. (2) Perform mechanistic studies whose goal is to define how HIV promotes expansion of profibrotic macrophage polarization. We will specifically evaluate HIV's effects on liver macrophages using RNA-Seq, and will assess the contribution of EGFR signaling to HIV's effects on the macrophage population by performing inhibitor studies. We will also assess HIV's promotion of fibrogenesis using stellate cell cocultures. (3) Evaluate the effects of antiretroviral suppression of HIV on hepatic macrophages in vitro and in vivo. The latter studies will be carried out using hepatic fine needle aspirates frm HIV/HCV coinfected persons undergoing initiation of ART. We will test the hypothesis that successful HIV suppression partially but does not fully reverse the effect of HIV on alteration of the profibrogenic macrophage phenotype. These studies will shed great light on the contribution of the macrophage to HIV-associated liver fibrosis progression.