HIV-1 Vpr combats the PU.1-driven antiviral response in primary human macrophages

The HIV-1 accessory protein, Vpr, is an enigmatic protein required for efficient spread of HIV from macrophages to T cells, a necessary step for propagation of infection. To illuminate the role of Vpr in HIV-infection of primary macrophages, we used single-cell RNA sequencing to capture the transcriptional changes during an HIV-1 spreading infection plus and minus Vpr. We found that Vpr reprogramed HIV-infected macrophage gene expression by targeting the master transcriptional regulator, PU.1. PU.1 was required for efficient induction of the host innate immune response to HIV, including upregulation of ISG15, LY96, and IFI6. In contrast, we did not observe direct effects of PU.1 on HIV gene transcription. Single cell gene expression analysis also revealed Vpr countered an innate immune response to HIV-infection within bystander macrophages via a PU.1-independent mechanism. The capacity of Vpr to target PU.1 and disrupt the anti-viral response was highly conserved across primate lentiviruses including HIV-2 and several SIVs. By demonstrating how Vpr overcomes a critical early warning system of infection, we identify a crucial reason why Vpr is necessary for HIV infection and spread.