P2X1 selective antagonists block HIV-1 infection through inhibition of envelope conformation-dependent fusion

Purinergic receptors detect extracellular ATP and promote inflammatory processes. Emerging literature has demonstrated that inhibition of these proinflammatory receptors can block HIV-1 productive infection. The specificity of receptor type and mechanism of interaction has not yet been determined. Here we characterize the inhibitory activity of P2X1 receptor antagonists, NF279 and NF449 in cell lines, primary cells, and in a variety of envelope clades. NF279 and NF449 blocked productive infection at the level of viral membrane fusion with a range of inhibitory activities against different HIV-1 envelopes. A mutant virus carrying a truncation deletion of the C-terminal tail of HIV-1 envelope (Env) glycoprotein 41 (gp41) showed reduced sensitivity to P2X1 antagonists, indicating that the sensitivity of inhibition by these molecules is modulated by Env conformation. By contrast, a P2X7 antagonist, A438079, had limited effect on productive infection and fusion. Inhibition with NF449 interfered with the ability of the V1V2 targeted broadly neutralizing antibody PG9 to block productive infection, suggesting that these drugs may antagonize HIV-1 Env at gp120 V1V2 to block viral membrane fusion. Our observations indicate that P2X1 antagonism can inhibit HIV-1 replication at the level of viral membrane fusion through interaction with Env. Future studies will probe the nature of these compounds in inhibiting HIV-1 fusion and in development of a different class of small molecules to block HIV-1 entry.\n\nIMPORTANCEWhile effective treatment can lower the severe morbidity and mortality associated with HIV-1 infection, patients infected with HIV-1 suffer from significantly higher rates of non-communicable comorbidities associated with chronic inflammation. Emerging literature suggests a key role for P2X1 receptors in mediating this chronic inflammation but the mechanism is still unknown. Here, we demonstrate that HIV-1 infection is reduced by P2X1 receptor antagonism. This inhibition is mediated by interference with HIV-1 Env and can impact a variety of viral clades. These observations highlight the importance of P2X1 antagonists as potential novel therapeutics that could serve to block a variety of different viral clades with additional benefits for their anti-inflammatory properties.