HIV Tat and HBV HBx in HIV/HBV Coinfection-associated Liver Disease

摘要 在全球范围内，估计有2.5亿人慢性感染乙肝病毒(乙肝病毒)，估计 3800万人感染了人类免疫缺陷病毒1型(HIV-1)。10%-25%的艾滋病毒感染者 个人会同时感染乙肝病毒。慢性乙肝病毒感染是肝细胞癌最常见的危险因素 癌症(HCC)。HIV感染对肝脏也有病理影响，并增加了患肝癌的风险 艾滋病毒/乙肝病毒混合感染。HIV/HBV二重感染引起肝病的分子机制尚不清楚 明白了。当接受抗病毒治疗(AT)时，无论是单一感染还是联合感染，HIV-1和 乙肝病毒可能是检测不到的。对于HIV来说，这会将疾病推向与增加相关的慢性状态 合并症，包括几种癌症。批准的抗HIV和抗HBVAT不能阻断病毒蛋白 在HIV或乙肝病毒感染的细胞中合成，即使在AT中也表达HIV TAT和HBx蛋白。HBX 是体内复制乙肝病毒所必需的，调节细胞信号，如凋亡信号，影响 致癌，并在HBx转基因小鼠中引起肝癌。TAT在慢性HIV疾病中也有作用，可以改变 凋亡信号，并导致TAT转基因小鼠的肝癌。乙肝病毒感染肝细胞；然而，艾滋病毒是否 在自然感染中感染肝细胞的机制尚不清楚，如果是这样的话，研究表明这是无效的。在一个感染了艾滋病毒的人中 就个人而言，即使在AT患者的循环血液中，TAT也存在，在艾滋病毒/乙肝病毒混合感染的情况下，循环TAT可能 在肝脏中提供信号以增强乙肝病毒诱导的肝细胞癌。库普弗细胞(KCs)是驻留在肝脏的巨噬细胞 它可能被艾滋病毒感染，预计会在肝脏中分泌促炎细胞因子和TAT。 我们假设，在艾滋病毒/乙肝病毒混合感染中，Tat作为一种细胞外蛋白或其组合的影响 与来自HIV感染的KCs的其他细胞大分子一起，增强HBx驱动的细胞信号调节 乙肝病毒复制和/或肝细胞凋亡，导致包括肝癌在内的肝脏疾病的风险增加，如 与单一感染相比。这项提案的目标是确定HBX和TAT的合作活动 影响乙肝病毒感染的肝细胞的复制和凋亡，并确定其机制 协同效应。我们将：1)确定TAT如何与HBx合作影响乙肝病毒复制和肝细胞 细胞凋亡；以及2)确定艾滋病毒感染的KCs如何影响乙肝病毒复制和肝细胞凋亡以及如何 这与TAT活动有关。我们将使用表达乙肝病毒或HBx的重组腺病毒(AdHBx)感染 原代培养人肝细胞(PHHs)。TAT将作为外源纯化蛋白提供，作为一个组成部分 来自HIV感染的KCs的条件细胞培养液，或来自HIV感染的KCs与乙肝病毒-或 AdHBx感染的PHHs。我们将评估TAT如何单独或与艾滋病毒感染者产生的因素结合起来 KCS，影响乙肝病毒复制和肝细胞凋亡。这些研究应该会带来翻译机会， 例如开发TAT和HBx信号相互作用的抑制剂，或诊断增加的肝细胞癌风险。

SUMMARY Globally, an estimated 250 million people are chronically infected with hepatitis B virus (HBV) and an estimated 38 million people are infected with human immunodeficiency virus type 1 (HIV-1). 10-25% of HIV-infected individuals are co-infected with HBV. A chronic HBV infection is the most common risk factor for hepatocellular carcinoma (HCC). HIV infection also has pathological effects in the liver and increases the risk for HCC in HIV/HBV co-infection. The molecular mechanisms underlying liver disease in HIV/HBV co-infection are poorly understood. When treated with antiviral therapy (AT), either for mono- or co-infection, the viral load of HIV-1 and HBV can be undetectable. For HIV, this pushes the disease to a chronic state that is associated with increased comorbidities, including several types of cancer. Approved anti-HIV and anti-HBV AT do not block viral protein synthesis in HIV- or HBV-infected cells, and the HIV Tat and HBV HBx proteins are expressed even with AT. HBx is required for in vivo HBV replication, regulates cell signals, such as apoptotic signals, that influence carcinogenesis, and causes HCC in HBx-transgenic mice. Tat also has a role in chronic HIV disease, can alter apoptotic signals, and causes HCC in Tat-transgenic mice. HBV infects hepatocytes; however, whether HIV infects hepatocytes in a natural infection is unclear, and if so, studies indicate this is inefficient. In an HIV-infected individual, Tat is in the circulating blood even with AT, and in an HIV/HBV co-infection, circulating Tat could provide signals in the liver to enhance HBV-induced HCC. Kupffer cells (KCs) are liver-resident macrophages that can be infected by HIV and would be expected to secrete pro-inflammatory cytokines and Tat in the liver. We hypothesize that in an HIV/HBV co-infection, the effects of Tat, as an extracellular protein or in combination with other cellular macromolecules from HIV-infected KCs, enhance HBx-driven cellular signals that regulate HBV replication and/or hepatocyte apoptosis, leading to an elevated risk for liver disease, including HCC, as compared to mono-infection. The goal of this proposal is to determine whether cooperative HBx and Tat activities affect HBV replication and apoptosis in HBV-infected hepatocytes and define mechanisms underlying cooperative effects. We will: 1) Determine how Tat cooperates with HBx to affect HBV replication and hepatocyte apoptosis; and 2) Determine how HIV-infected KCs affect HBV replication and hepatocyte apoptosis and how this is linked to Tat activities. We will use HBV- or HBx-expressing recombinant adenovirus (AdHBx)-infected cultured primary human hepatocytes (PHHs). Tat will be provided as exogenous purified protein, as a component of conditioned cell culture medium from HIV-infected KCs, or from co-culture of HIV-infected KCs with HBV- or AdHBx-infected PHHs. We will assess how Tat, alone or in combination with factors produced in HIV-infected KCs, affects HBV replication and hepatocyte apoptosis. These studies should lead to translational opportunities, such as developing inhibitors for interacting Tat and HBx signals or diagnostics for increased HCC risk.