HIV-1 Nef induces astrocytes proliferation, inflammatory response, A1-like astrocytes polarization and subsequent neuronal apoptosis via NF-κB signaling pathway

Currently, human immunodeficiency virus-1 (HIV-1) spreads around the globe and half of HIV-1-positive individuals suffer from HIV-associated neurocognitive disorder (HAND). HIV-1 Infection of astrocytes leads to neuroinflammation and neuronal injury. However, the underlying molecular mechanisms of HIV-1 negative factor (Nef)-mediated astrocytic dysfunction, remain largely unclear. In the present study, our data showed that astrocytic Nef expression facilitated astrocytes proliferation, pro-inflammatory cytokines production and A1-like astrocytes polarization. Mechanistically, Nef-activated NF-κB p65 directly bound to the promoter regions of the proliferative marker (CyclinD1), the inflammatory genes (IL-6, Ccl2, Ccl5 and Cxcl10) and the A1-specific marker (C3), and upregulated these genes expression at transcriptional levels. Conversely, NF-κB signaling inhibitor BAY11-7082 (2 μM) or RNA interference targeting of NF-κB p65 markedly mitigated astrocytes-mediated Nef neurotoxicity. Moreover, Nef-transduced astrocytes-derived conditioned media induced large amount of apoptotic HT-22 and SH-SY5Y neural cells, which was remarkably reversed in response to NF-κB inhibition. Finally, in animal models, we determined that knockdown of NF-κB p65 effectively ameliorated Nef‑induced neuroinflammation, A1-like astrocytes polarization and neuronal death. Taken together, our data suggest that Nef induces astrocytes proliferation, inflammatory response, A1-like astrocytes polarization and neuronal death in a NF-κB-dependent manner. Our findings propose that NF-κB signaling might be a desirable therapeutic target for relief of astrocytes-mediated Nef neurotoxicity.