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

Abstract

word count: 350 35 Text word count: 6244 36 37 38 39 3 Abstract 40 41 Purinergic receptors detect extracellular ATP and promote inflammatory processes. Emerging literature 42has demonstrated that inhibition of these proinflammatory receptors can block HIV-1 productive infection. The 43 specificity of receptor type and mechanism of interaction has not yet been determined. Here we characterize 44 the inhibitory activity of P2X1 receptor antagonists, NF279 and NF449 in cell lines, primary cells, and in a 45 variety of envelope clades. NF279 and NF449 blocked productive infection at the level of viral membrane 46 fusion with a range of inhibitory activities against different HIV-1 envelopes. A mutant virus carrying a 47 truncation deletion of the C-terminal tail of HIV-1 envelope (Env) glycoprotein 41 (gp41) showed reduced 48 sensitivity to P2X1 antagonists, indicating that the sensitivity of inhibition by these molecules is modulated by 49 Env conformation. By contrast, a P2X7 antagonist, A438079, had limited effect on productive infection and 50 fusion. Inhibition with NF449 interfered with the ability of the V1V2 targeted broadly neutralizing antibody PG9 51 to block productive infection, suggesting that these drugs may antagonize HIV-1 Env at gp120 V1V2 to block 52 viral membrane fusion. Our observations indicate that P2X1 antagonism can inhibit HIV-1 replication at the 53 level of viral membrane fusion through interaction with Env. Future studies will probe the nature of these 54 compounds in inhibiting HIV-1 fusion and in development of a different class of small molecules to block HIV-1 55 entry. 56 57 IMPORTANCE: 58While effective treatment can lower the severe morbidity and mortality associated with HIV-1 infection, patients 59 infected with HIV-1 suffer from significantly higher rates of non-communicable comorbidities associated with 60 chronic inflammation. Emerging literature suggests a key role for P2X1 receptors in mediating this chronic 61 inflammation but the mechanism is still unknown. Here, we demonstrate that HIV-1 infection is reduced by 62 P2X1 receptor antagonism. This inhibition is mediated by interference with HIV-1 Env and can impact a variety 63 of viral clades. These observations highlight the importance of P2X1 antagonists as potential novel 64 therapeutics that could serve to block a variety of different viral clades with additional benefits for their anti-65 inflammatory properties.

Purinergic Receptors: Elucidating the Role of These Immune Mediators in HIV-1 Fusion

“…Numerous studies describe the role of purinergic receptors and their antagonists at various stages of the viral life cycle and downstream impacts on pathogenesis. In the following section, we will review the literature as it pertains to the role of purinergic receptors and their antagonists on HIV- P2X7R and P2YR antagonists have been shown to inhibit HIV-1 infection at potencies similar to those of P2X1R antagonists (94,97,(116)(117)(118)(119), but these compounds do not appear to impact virus-cell membrane fusion. The P2X7R antagonist A740003, which inhibits HIV-1 infection (94), fails to inhibit virus-membrane fusion as measured by BlaM-Vpr assays (94,114,118).…”

“…The same assay demonstrated that the broad-spectrum P2 receptor inhibitor PPADS likewise has no effect on virus-membrane fusion, Our laboratory additionally demonstrated that NF449 and NF279-mediated fusion inhibition relies on intact gp41 and displays varied activity against diverse clades. The inhibitory activity of NF279 and NF449 appeared to interfere specifically with Env, as NF279 and NF449 inhibited viral membrane fusion and impacted PG9 antibody accessibility, which targets the V1V2 region of HIV-1 gp120 (119).…”