Janevska Marija, Witkowski Wojciech, Vermeire Jolien, Borowicz Marek, Naessens Evelien, Vanderstraeten Hanne, Nauwynck Hans, Favoreel Herman, Verhasselt Bruno
Department of Diagnostic Sciences, Faculty of Medicine and Life Sciences, Ghent University, Ghent, Belgium.
Department of Internal Medicine and Pediatrics, Faculty of Medicine and Life Sciences, Ghent University, Ghent, Belgium.
J Virol. 2025 Apr 15;99(4):e0206624. doi: 10.1128/jvi.02066-24. Epub 2025 Mar 3.
HIV-1 infects several types of CD4+ cells. Among these, dendritic cells (DCs) are considered one of the first to encounter the virus upon sexual transmission. Expression of several restriction factors, of which SAMHD1 is well known, limits productive infection. Still, DCs are essential players in shaping adaptive immune responses that contribute heavily to the pathogenesis of HIV. Here, we set out to identify other factors that potentially contribute to the resistance of dendritic cells to HIV infection. Since endocytosis and the cytoskeleton impact HIV infection, we have put special emphasis on proteins implied in these pathways. In a selective, shRNA-mediated knockdown screen in primary monocyte-derived dendritic cells (MDDCs) infected with HIV in the presence of SAMHD1-disactivating Vpx containing virus-like particles, three proteins hampering HIV-1 infection were identified: FNBP1L, ARHGAP24, and ATP6V1B1. Findings of our research indicate that upon blocking of factors involved in endocytosis, increased viral entry is observed providing supportive evidence for endocytosis mostly being a dead-end entry pathway for HIV infection of MDDCs. Additional experiments show that changes in the cytoskeleton and endosomal pH that lead to impaired fluid-phase endocytosis and phagocytosis are responsible for these shifts in the phenotype observed.IMPORTANCEUnderstanding how HIV-1 interacts with dendritic cells (DCs) is pivotal in deciphering early viral transmission and immune evasion but is subject to a long-standing controversy in HIV virology. Therefore, the identification of endocytosis-related host factors as barriers to productive infection in DCs emphasizes the role of endocytosis as a restrictive pathway for viral entry. By disrupting these processes, we highlight a shift in the cellular environment that could influence viral entry and transmission. These findings challenge existing models of HIV-1 entry into DCs. New insights into how cellular pathways limit viral spread have implications for the development of strategies aimed to curb viral dissemination and reservoir formation. Whether the knockdown of the proteins described simply augments the efficiency of infection via existing pathways or opens additional routes for HIV-1 entry remains to be investigated.
HIV-1可感染多种类型的CD4+细胞。其中，树突状细胞（DCs）被认为是性传播时最早接触该病毒的细胞之一。多种限制因子的表达，其中SAMHD1最为人所知，可限制病毒的有效感染。尽管如此，DCs仍是塑造适应性免疫反应的关键因素，对HIV的发病机制有重大影响。在此，我们着手鉴定其他可能导致树突状细胞对HIV感染产生抗性的因素。由于内吞作用和细胞骨架会影响HIV感染，我们特别关注了这些途径中涉及的蛋白质。在一项选择性的、shRNA介导的敲低筛选实验中，我们使用含有可使SAMHD1失活的Vpx的病毒样颗粒感染原代单核细胞衍生的树突状细胞（MDDCs），鉴定出了三种阻碍HIV-1感染的蛋白质：FNBP1L、ARHGAP24和ATP6V1B1。我们的研究结果表明，在内吞作用相关因子被阻断后，病毒进入增加，这为内吞作用大多是HIV感染MDDCs的一条死胡同式进入途径提供了支持性证据。额外的实验表明，细胞骨架和内体pH的变化导致液相内吞作用和吞噬作用受损，是观察到的表型变化的原因。重要性了解HIV-1如何与树突状细胞（DCs）相互作用对于解读早期病毒传播和免疫逃逸至关重要，但在HIV病毒学领域一直存在长期争议。因此，鉴定与内吞作用相关的宿主因子作为DCs中有效感染的障碍，强调了内吞作用作为病毒进入的限制途径的作用。通过破坏这些过程，我们突出了细胞环境的变化，这种变化可能影响病毒进入和传播。这些发现挑战了现有的HIV-1进入DCs的模型。关于细胞途径如何限制病毒传播的新见解对旨在遏制病毒传播和储存库形成的策略的开发具有重要意义。所描述蛋白质的敲低是仅仅提高了通过现有途径的感染效率，还是为HIV-1进入开辟了额外途径，仍有待研究。
