Wikstrol B reactivates latent human immunodeficiency virus (HIV-1) via the nuclear factor-κB (NF-κB) pathway

Combination antiretroviral therapy (cART) and latency-reversing agents (LRAs) have not achieved a successful cure of HIV infection, due to latent HIV reservoir for the former, and insufficient efficacy and adverse side effects for the latter. Therefore, candidate LRAs with high antiviral efficacy and low cytotoxicity are critical for achieving a functional cure of HIV-1 infection.

To identify promising flavonoids with dual functions in reactivating latent HIV-1 and inhibiting viral infection, and to explore the mechanisms involved therein.

We screened 21 flavonoids from Stellera chamaejasme and selected wikstrol B as a promising LRA candidate. The effects of the candidate on latent HIV-1 reactivation were assessed using enzyme-linked immunosorbent assay (ELISA), reverse-transcription quantitative PCR (RT-qPCR), and flow cytometry. Its cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry, western blot (WB) analysis, confocal microscopy and chromatin immunoprecipitation (ChIP) assay were applied for mechanism exploration. Anti-HIV-1 activity was assessed with ELISA, and the effect of wikstrol B on the Vif/hA3G complex was evaluated by co-immunoprecipitation (Co-IP) assay. Additionally, synergy of wikstrol B with cART drugs or other LRAs were also tested.

Wikstrol B effectively reversed HIV-1 latency in both latently infected cell lines and primary CD4⁺ T cells at low micromolar concentrations with minimal cytotoxicity. As for mechanisms, wikstrol B specifically induced HIV-1 long terminal repeat (LTR) transactivation and reactivated latent HIV-1 transcription by modulating the NF-κB signaling pathway. Additionally, wikstrol B demonstrated potent inhibitory activity against the laboratory-adapted HIV-1_IIIB strain by blocking Vif-mediated degradation.

Wikstrol B is capable of both reactivating latent HIV-1 and inhibiting HIV-1 infection with few adverse effects, and may be applied, preferably in synergistic combination with cART drugs and other LRAs, in the "shock and kill" strategy for treating Acquired Immune Deficiency Syndrome (AIDS).