Potent HIV fusion inhibitors against Enfuvirtide-resistant HIV-1 strains

Human immunodeficiency virus (HIV) gp41 plays a key role in viral fusion; the N-and C-terminal heptad repeats (N-HR and C-HR) of gp41 form a stable 6-helical conformation for fusion. Therefore, HR-derived peptides, such as enfuvirtide (T-20), inhibit HIV-1 fusion by acting as decoys, and have been used for the treatment of HIV-1 infection. However, the efficacy of T-20 is attenuated by resistance mutations in gp41, including V38A and N43D. To suppress the resistant variants, we previously developed electrostatically constrained peptides, SC34 and SC34EK, and showed that both exhibited potent anti-HIV-1 activity against wild-type and T-20-resistant variants. In this study, to clarify the resistance mechanism to this next generation of fusion inhibitors, we selected variants with resistance to SC34 and SC34EK in vitro. The resistant variants had multiple mutations in gp41. All of these mutations individually caused less than 6-fold resistance to SC34 and SC34EK, indicating that there is a significant genetic barrier for high-level resistance. Cross-resistance to SC34 and SC34EK was reduced by a simple difference in the polarity of two intramolecular electrostatic pairs. Furthermore, the selected mutations enhanced the physicochemical interactions with N-HR variants and restored activities of the parental peptide, C34, even to resistant variants. These results demonstrate that our approach of designing gp41-binding inhibitors using electrostatic constraints and information derived from resistance studies produces inhibitors with enhanced activity, high genetic barrier, and distinct resistance profile from T-20 and other inhibitors. Hence, this is a promising approach for the design of future generation peptide fusion inhibitors.

Section: Table 3 Antiviral Activity Of Fusion Inhibitors To Sc34-and mentioning

confidence: 99%

Resistance Profiles of Novel Electrostatically Constrained HIV-1 Fusion Inhibitors

Shimura

Nameki

Kajiwara

et al. 2010

“…Specifically, the C-peptides CP-32 (aa 621-652) and CP-32M, which contain an AVERY-binding motif, QIWNNMT (aa 621-627) (Fig. 1B), are more potent than T20 in blocking 6-HB formation and inhibiting infection by HIV-1 strains, including those resistant to T20 and C34 (28,29). N28 contains the 17-mer pocket-forming sequence (N17) plus the hexamer IEAQQH (aa 559 -564) sequence and the 5-mer AVERY motif at the N and C termini of N17 sequence, respectively (Fig.…”

Section: Design Of N36fd and N28fdmentioning

confidence: 99%

Novel Recombinant Engineered gp41 N-terminal Heptad Repeat Trimers and Their Potential as Anti-HIV-1 Therapeutics or Microbicides

Chen

et al. 2010

Self Cite

Peptides derived from N-terminal heptad repeat (NHR) of the HIV-1 gp41 are generally poor inhibitors of HIV-1 entry, because they tend to aggregate and do not form a trimeric coiled-coil. In this study, we have fused portions of gp41 NHR, e.g. N36 or N28, to the T4 fibritin trimerization domain, Foldon (Fd), thus constructing novel NHR trimers, designated N36Fd or N28Fd, which could be expressed in Escherichia coli cells. The purified N36Fd and N28Fd exhibited SDS-resistant trimeric coiled-coil conformation with improved ␣-helicity compared with the corresponding N-peptides. They could interact with a C-peptide (e.g. C34) to form stable six-helix bundle and possessed potent anti-HIV-1 activity against a broad spectrum of HIV-1 strains. N28Fd was effective against T20-resistant HIV-1 variants and more resistant to proteinase K compared with T20 (enfuvirtide), a C-peptide-based HIV fusion inhibitor. Therefore, N28Fd trimer has great potentials for further development as an affordable therapeutic or microbicide for treatment and prevention of HIV-1 infection.

“…In this fusion-active gp41 core structure, three N-terminal heptad repeat regions (NHR) form a central trimeric coiled coil, whereas three C-terminal heptad repeat regions (CHR) around the NHR pack as antiparallel helices into hydrophobic grooves (3)(4)(5)(6). A number of synthetic peptides derived from the NHR and CHR of gp41 can efficiently inhibit HIV-1 infection by competitively binding to the exposed NHR or CHR in the gp41 pre-hairpin state, hence blocking 6-HB formation in a dominant-negative manner (7)(8)(9)(10)(11)(12)(13)(14)(15). Among them, T20 (Enfuvirtide, Fuzeon) has been approved for clinical use as the first member of a new class of anti-HIV drugs, HIV fusion inhibitors (9,16,17).…”

mentioning

confidence: 99%

“…In succession to T20, the second-generation peptide fusion inhibitor T1249 was developed with increased antiviral potency, but its clinical development was halted due to the drug formulation problem (14,22,23). Among a series of more potent third generation fusion inhibitors (10,(12)(13)(14)(15), sifuvirtide (SFT) is one in advance stages. It has been evaluated by the phase I clinical trials and is currently under phase II clinical studies (13,24).…”

mentioning

confidence: 99%

Broad Antiviral Activity and Crystal Structure of HIV-1 Fusion Inhibitor Sifuvirtide

Xue

Chong

Zhang

et al. 2012

Self Cite

Background: Sifuvirtide (SFT) is an HIV peptide fusion inhibitor under phase II clinical trials. Results: Crystal structure of SFT complexed with gp41 NHR peptide and the potent activity of SFT against diverse HIV-1 variants were determined. Conclusion: Crystal structure fully supports earlier peptide design. Significance: Our data present important information for developing SFT for clinical use and for designing novel HIV fusion inhibitors.