Role Of Monocytes In AIDS And As Targets For Antiviral Therapy

宿主细胞因子作为破坏HIV生命周期的靶点： 艾滋病毒复杂的生命周期涉及与宿主细胞成分的关键功能相互作用，这些宿主细胞因子可能代表治疗干预的靶点。 此外，设计用于干扰病毒对宿主细胞因子的必要利用的HIV药物被认为比针对易于突变的病毒成分的药物更不可能促进耐药株的发展。HIV结合/进入以及产生性感染所需的细胞基因已被确定为抗HIV药物开发的潜在靶点。因此，鉴定参与早期事件的细胞基因，无论是在病毒体进入、病毒DNA合成或前病毒整合或病毒转录物的产生的水平上，作为阻断病毒生命周期的关键靶标，仍然是高度优先的。参与HIV生命周期的一种宿主细胞分子是载脂蛋白B mRNA编辑催化多肽样3G（APOBEC 3G），其是具有针对HIV的致死活性的先天性细胞内蛋白。最初被认为是组成型表达和耗尽的病毒，我们的研究表明，这种宿主防御分子的水平可以通过干扰素增强，伴随着对HIV的抗性。 在已鉴定的对HIV在巨噬细胞中的成功生命周期具有强制性的其他基因中，有p21，一种细胞周期蛋白依赖性激酶抑制剂1A（CDKN 1A）。HIV病毒蛋白R（Vpr）促进病毒在非分裂细胞中的复制，并且是在组织巨噬细胞中复制的晚期阶段中有效产生HIV-1所必需的，被发现代表HIV-1驱动p21转录的途径。重要的是，通过已知影响p21表达的siRNA、反义或合成的三萜类化合物2-氰基-3，12-二氧代齐墩果烷-1，9-二烯-28-酸（CDDO）抑制p21抑制病毒复制。这些数据暗示p21是病毒复制所必需的巨噬细胞促进剂。 此外，这种分子的调节剂，如CDDO，可以提供一种干预方法来调节HIV-1复制。 HIV感染中的粘蛋白靶向和耐药因素： 人类扁桃体是HIV复制的靶点和潜在储存库。 口服HIV-1传播虽然罕见，但并不排除这种次级淋巴器官在疾病进展时最初或继发严重感染。 为了确定哪些独特的因素有利于扁桃体淋巴组织中观察到的大规模感染，将扁桃体对HIV感染的易感性与外周血单核细胞（PBMC）和静息T淋巴细胞进行了比较。在这些研究中，我们确定了扁桃体微环境的几个独特方面，这些方面可能支持扁桃体对HIV感染的容许性。在培养中，如原位发生的那样，扁桃体细胞对HIV更宽容，不依赖于额外的外源性刺激。通过一系列的分析，包括转录、信号转导和蛋白质组学，我们确定了扁桃体允许逆转录病毒的多个因素。这样的免疫调节模式对于控制免疫激活是必要的，但在抗原和病原体不断轰击的环境中保持准备状态，但不幸的是，这代表了HIV复制的有利条件。在正在进行的研究中，扁桃体Treg，巨噬细胞和树突状细胞作为HIV发病机制中病毒的潜在调节剂和靶标的贡献也正在被剖析。进一步了解这些免疫调节途径及其对HIV发病机制的贡献，将促进操纵脆弱的粘膜隔室的策略。 虽然扁桃体可以作为艾滋病毒复制的储存库，但扁桃体是否可以作为人与人之间传播艾滋病毒的管道仍不清楚。 我们从扁桃体中分离上皮细胞，并将扁桃体上皮细胞的遗传特征与牙龈上皮细胞的遗传特征进行比较。 在这两种组织的变异中，扁桃体上皮细胞中CXCR 4基因的表达明显较高，该基因编码一种表面蛋白，HIV可以在进入细胞前将其自身锚在细胞上。 扁桃体上皮中潜在HIV结合分子的基因表达增加（FcR γ、补体受体2和补体成分），以及具有潜在抗HIV活性的先天免疫分子水平较低（SLPI、β-防御素和血小板反应蛋白），这表明，与HIV结合和进入相关的分子表达增加，加上先天性抗病毒因子减少，可能使扁桃体成为HIV感染的潜在部位。传输这些和其他独特的扁桃体微环境线索有利于环境，使扁桃体细胞易受HIV感染，并强调局部免疫调节机制的作用，这可能是粘膜隔室内HIV感染的选择性。

Host Cell Factors as Targets to Disrupt the HIV Life Cycle: The complex life cycle of HIV involves critical functional interactions with host cell components, and these host cell factors may represent targets for therapeutic intervention. Furthermore, HIV drugs designed to interfere with requisite utilization of host cell factors by the virus are considered less likely to foster development of resistant strains than drugs directed against viral components prone to mutation. Cellular genes required for binding/entry and also productive infection by HIV have been identified as potential targets for anti-HIV drug development. Consequently, identification of cellular genes that are involved in early events, whether at the level of virion entry, viral DNA synthesis or proviral integration or production of viral transcripts remain a high priority as pivotal targets for blocking the viral life cycle. One host cell molecule(s) which is involved in the HIV life cycle is apolipoprotein B mRNA-editing catalytic polypeptide-like 3G (APOBEC3G), which is an innate intracellular protein with lethal activity against HIV. Originally thought to be constitutively expressed and depleted by the virus, our studies demonstrate that the levels of this host defense molecule can be augmented by interferon, concomitant with resistance to HIV. Among the additional genes identified which are obligatory to the successful life cycle of HIV in macrophages is p21, a cyclin-dependent kinase inhibitor 1A (CDKN1A). The HIV viral protein R (Vpr), which facilitates virus replication in non-dividing cells and is required for efficient HIV-1 production in late stages of replication in tissue macrophages, was found to represent a pathway by which HIV-1 drives p21 transcription. Importantly, inhibition of p21 by siRNA, antisense, or a synthetic triterpenoid, 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO), known to influence p21 expression, suppressed viral replication. These data implicate p21 as a requisite macrophage facilitator of viral replication. Moreover, regulators of this molecule, such as CDDO, may provide an interventional approach to modulate HIV-1 replication. Mucosal targeting and resistance factors in HIV infection: The human tonsil represents a target and potential reservoir for HIV replication. Oral HIV-1 transmission, although rare, does not preclude this secondary lymphoid organ from becoming heavily infected either initially or secondarily as the disease progresses. In order to identify what unique factors favor the massive infection seen in tonsil lymphoid tissues, tonsil susceptibility to HIV infection was compared with that of peripheral blood mononuclear cells (PBMC) and resting T lymphocytes. In these studies, we identified several unique aspects of the micromilieu of the tonsil that may support the permissive nature of the tonsil to HIV infection. In culture, as occurs in situ, tonsil cells are more permissive for HIV, independent of additional exogenous stimulation. By a battery of analyses, including transcriptional, signal transduction, and proteomic, we identified multiple contributory elements to the retroviral permissive nature of the tonsil. Such a profile of immune regulation is necessary to control immune activation, yet maintain a state of readiness in an environment constantly bombarded with antigens and pathogens, but which unfortunately represents a favorable condition for HIV replication. In ongoing studies, the contribution of tonsil Treg, macrophages and dendritic cells as potential regulators and targets for the virus in HIV pathogenesis is also being dissected. Further understanding of these immunoregulatory pathways and their contribution to HIV pathogenesis will promote strategies for manipulating vulnerable mucosal compartments. Although tonsils may serve as reservoirs for the replication of HIV, whether the tonsils serve as a conduit for person to person HIV transmission remains unclear. We isolated epithelial cells from the tonsil and compared the genetic profile of the tonsil epithelium with that of gingival epithelial cells. Among the variations in the two tissues was significantly higher expression in the tonsil epithelium of the CXCR4 gene, which encodes a surface protein that HIV can use to anchor itself to cells before entry. Increased gene expression in the tonsil epithelium of potential HIV-binding molecules (FcRgamma, complement receptor 2, and complement components), together with lower levels of innate immune molecules with potential anti-HIV activity (SLPI, beta-defensins, and thrombospondin), suggest that increased expression of molecules associated with HIV binding and entry coupled with decreased innate antiviral factors may render the tonsil a potential site for transmission. These and other unique tonsillar microenvironmental cues favor a milieu that renders tonsil cells susceptible to HIV infection and underscore the role of local immune regulatory mechanisms which may account for the selectivity of HIV infection within mucosal compartments.