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

总结 在全球范围内，估计有2.5亿人慢性感染B型肝炎病毒（HBV）， 3 800万人感染了人类免疫缺陷病毒1型（艾滋病毒-1）。10-25%的艾滋病毒感染者 个人同时感染HBV。慢性HBV感染是肝细胞癌最常见的危险因素。 癌（HCC）。艾滋病毒感染还对肝脏产生病理影响，并增加患肝癌的风险。 HIV/HBV合并感染。HIV/HBV合并感染引起肝病的分子机制尚不清楚， 明白当接受抗病毒治疗（AT）时，无论是单一感染还是合并感染，HIV-1的病毒载量和 HBV可以检测不到。对于艾滋病毒，这将疾病推向慢性状态， 合并症，包括几种癌症。获批的抗HIV和抗HBV AT不阻断病毒蛋白 在HIV或HBV感染的细胞中合成，并且HIV达特和HBV HBx蛋白甚至与AT一起表达。HBX 是体内HBV复制所需的，调节细胞信号，如凋亡信号，影响 致癌作用，并导致HBx转基因小鼠中的HCC。达特在慢性艾滋病中也有作用，可以改变 凋亡信号，并导致Tat转基因小鼠中的HCC。HBV感染肝细胞;然而， 在自然感染中感染肝细胞尚不清楚，如果是这样，研究表明这是低效的。hiv感染 在个体中，达特甚至与AT一起存在于循环血液中，并且在HIV/HBV合并感染中，循环达特可以 在肝脏中提供信号以增强HBV诱导的HCC。枯否细胞（KCs）是肝脏驻留的巨噬细胞 其可被HIV感染并预期在肝脏中分泌促炎细胞因子和达特。 我们假设，在HIV/HBV合并感染中，达特作为细胞外蛋白或联合作用 与来自HIV感染的KC的其他细胞大分子一起，增强HBx驱动的细胞信号， HBV复制和/或肝细胞凋亡，导致肝病（包括HCC）风险升高， 与单一感染相比。本提案的目标是确定HBx和达特合作活动是否 影响HBV感染肝细胞中HBV复制和细胞凋亡，并确定其机制 协同效应我们将：1）确定达特如何与HBx合作影响HBV复制和肝细胞 细胞凋亡;和2）确定HIV感染的KC如何影响HBV复制和肝细胞凋亡，以及如何影响HBV复制和肝细胞凋亡。 这与达特的活动有关。我们将使用表达HBV或HBx的重组腺病毒（AdHBx）感染 培养的原代人肝细胞（PHH）。达特将作为外源性纯化蛋白提供，作为组分 来自HIV感染的KCs的条件细胞培养基，或来自HIV感染的KCs与HBV-或 AdHBx感染的PHH。我们将评估达特，单独或与艾滋病毒感染者产生的因素相结合， KCs影响HBV复制和肝细胞凋亡。这些研究应该会带来转化的机会， 例如开发用于相互作用的达特和HBx信号的抑制剂或用于增加HCC风险的诊断。

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.