The Hypoxia-regulated Ectonucleotidase CD73 is a Host Determinant of HIV Latency [RNA-seq]

Deciphering the mechanisms underlying viral persistence is critical to achieving a cure for HIV infection. Here, we implement a systems approach to discover molecular signatures of HIV latently-infected CD4+ T cells, identifying the immunosuppressive, adenosine-producing ectonucleotidase CD73 as a key surface marker of latent cells. Hypoxic conditioning, reflecting the lymphoid tissue microenvironment, increases the frequency of CD73+ CD4+ T cells and promotes HIV latency. Transcriptomic profiles of CD73+ CD4+ T cells favor viral quiescence, immune evasion, and cell survival. CD73+ CD4+ T cells are capable of harboring a functional HIV reservoir and reinitiating productive infection ex vivo. CD73 or adenosine receptor blockade facilitates latent HIV reactivation in vitro, mechanistically linking adenosine signaling to viral quiescence. Finally, tissue imaging of lymph nodes from HIV-infected individuals on antiretroviral therapy reveals spatial association between CD73 expression and HIV persistence in vivo. Our findings warrant development of HIV cure strategies targeting the hypoxia-CD73-adenosine axis. Overall design: Relatively little is known about the relevance and function of CD73 in human CD4+ T cells. To address this gap, the transcriptome of blood-derived, primary CD73+ and CD73- CD4+ T cells was characterized by RNA sequencing. To that purpose, CD73-/+ cells were isolated from primary CD4+ T cells by fluorescence-activated cell sorting and analyzed by RNA sequencing.

解析病毒持续感染的潜在机制对于实现HIV感染的治愈至关重要。本研究采用系统生物学方法，挖掘HIV潜伏感染CD4阳性T细胞（CD4+ T cells）的分子特征，鉴定出免疫抑制性腺苷生成型胞外核苷酸酶CD73（CD73）作为潜伏感染细胞的关键表面标志物。模拟淋巴组织微环境的低氧处理可提升CD73阳性CD4阳性T细胞的占比，并促进HIV潜伏。CD73阳性CD4阳性T细胞的转录组谱（transcriptomic profiles）特征有利于病毒静息、免疫逃逸与细胞存活。该类细胞可携带功能性HIV储存库（HIV reservoir）并在离体环境中重新启动产毒性感染（productive infection）。阻断CD73或腺苷受体可在体外促进潜伏HIV的激活，从而从机制上将腺苷信号通路与病毒静息关联起来。最后，对接受抗逆转录病毒治疗（antiretroviral therapy）的HIV感染者的淋巴结进行组织成像，发现体内CD73的表达与HIV持续感染存在空间关联。本研究结果支持针对低氧-CD73-腺苷轴开发HIV治愈策略。
实验设计：目前学界对CD73在人CD4阳性T细胞中的相关性与功能所知甚少。为填补这一研究空白，本研究通过RNA测序（RNA sequencing）对血液来源的原代CD73阳性与CD73阴性CD4阳性T细胞的转录组进行了表征。具体而言，研究人员通过荧光激活细胞分选术（fluorescence-activated cell sorting）从原代CD4阳性T细胞中分离出CD73阳性与CD73阴性细胞，并通过RNA测序进行分析。