Polypeptides inhibit HIV-1 replication by interfering viral Vpu-mediated tetherin degradation.

Background: HIV-1 Vpu acts by counteracting the tethering function of tetherin and resulting in the release of HIV-1 virion. Disrupting Vpu-tetherin interactions may provide a promising new target for antiretroviral therapy. Methods: Polypeptides that covered the amino acid sequence on the interface of Vpu-tetherin complex were designed. Phenotypic susceptibilities and cellular toxicities to the polypeptides were measured. The mechanisms of the anti-HIV-1 polypeptides were determined by the Western blot analysis and laser confocal scanning. Seven 20-mer polypeptides from wild-type Vpu amino acid sequence were designed. Results: We report the design and identification of 3 novel anti-HIV-1 polypeptides that derived from Vpu sequence which can efficiently inhibit HIV-1 infection. A pilot mechanism study showed that the active polypeptide could counteract Vpu-mediated tetherin downregulation. Laser confocal image scanning study showed that the polypeptides bound on the cell surface with a receptor specific binding manner, which may target tetherin that expressed on cell surface. Conclusion: Our work provided first evidence that counteracting Vpu-mediated tetherin downregulation could be a target for novel anti-HIV-1 drug design. Future works to provide direct evidence of inhibitors interact with tetherin at atomic resolution and the development of small molecules inhibitors targeting Vpu-tetherin interactions may open a new avenue for novel antiretroviral therapy.