Membrane Protein OTOF Is a Type I Interferon-Induced Entry Inhibitor of HIV-1 in Macrophages.

In humans, HIV-1 infection induces innate immune responses mediated mainly by type I interferon (IFN). Type I IFN restricts HIV-1 replication by upregulating the expression of IFN-stimulated genes with diverse anti-HIV properties. In this study, we report that the cell membrane protein otoferlin (OTOF) acts as a type I IFN-induced effector, inhibiting HIV-1 entry in myeloid lineage macrophages and dendritic cells (DCs). OTOF is significantly induced by type I IFN in macrophages and DCs but not in CD4 ⁺ T lymphocytes. Silencing OTOF abrogates the IFN-mediated suppression of HIV-1 infection in macrophages and DCs. Moreover, OTOF overexpression exhibits anti-HIV activity in macrophages and CD4 ⁺ T cells. Further evidence reveals that OTOF inhibits HIV-1 entry into target cells at the cell membrane. Collectively, OTOF is a downstream molecule induced by type I IFN to inhibit HIV-1 entry in macrophages; it is a new potential agent for the treatment of HIV infection. IMPORTANCE In patients with HIV-1 infection, the virus is recognized by innate immune sensors that trigger the production of type I interferons (IFNs), which are well-known cytokines that exert broad antiviral effects by inducing the expression of antiviral genes. By comparing the gene expression profiles of untreated patients and healthy donors, we systematically identified OTOF as a new antiviral gene induced by IFN-α in primary macrophages and dendritic cells (DCs). Additionally, silencing OTOF alleviates IFN-α-induced resistance to HIV-1 infection in both myeloid cell lineage macrophages and DCs. In contrast, OTOF overexpression potently restricts HIV-1 transmission in macrophages. We further explored the molecular mechanism through which OTOF inhibits the HIV-1 virion across the cell membrane. Overall, OTOF is a newly identified type I IFN-induced antiviral factor that inhibits the transmembrane activity of HIV-1 in myeloid cells.