Membrane role in the rational design of HIV fusion inhibitors

HOLLMANN, A; AUGUSTO, MT; GREGORIO, S; POROTTO M ; PESSI A; CASTANHO M; SANTOS NC

Sierra de la Ventana

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Biofísica; 2014

Sociedad Argentina de Biofisica

The Human Immunodeficiency Virus type 1 (HIV-1) is a highly pathogenic and evasive virus, for which no cure has yet been achieved. Fusion of viral and host cell membranes is a crucial step in virus infectivity, therefore the development of viral entry inhibitors has great advantages since they prevent the release of the viral content into the host cell. In this work, we found that boosting membrane affinity of the established HIV fusion inhibitors C34 and enfuvirtide, by conjugation with lipid moieties, results in a dramatic increase of their antiviral activity. We demonstrated, by fluorescent partition, dipole potential assays and surface pressure assays, that these novel fusion inhibitors have membranotropic behavior towards biomembrane model systems and human blood cells membranes. The ability that these peptides have to bind to cell membranes facilitates the delivery of the peptides to this confined environment, as some peptide is already locally present. Beside the ability of membranes to concentrate the inhibitors locally, their role in the presentation of the peptide in the proper orientation for gp41 binding should also be considered. In this context, we also evaluated the location of the different peptides in the membrane, using aqueous and lipophilics quenchers. Overall, the results of this study offer a rational basis for the design of improved viral fusion inhibitors, since they suggest that maximizing antiviral activity requires finding the proper balance of membrane affinity and exposure of the peptide moiety. Moreover, we offer an experimental strategy to guide the development of the structure-activity relationship (SAR) towards this goal.