Sulfated Glycans in HIV Infection and Therapy

The Human Immunodeficiency Virus (HIV) is the infectious agent causative of the Acquired Immune Deficiency Syndrome (AIDS). The number of HIV-infected people in the globe is incredibly large. Contrary to the big contamination rates, the incidence rate recently reported of AIDS-related deaths is fairly lower, less than 5% of the total infected population. The reduced rates of the AIDS-associated deaths rely primarily on the growing availability, variety and efficiency of the antiretroviral treatments. During the initial molecular events of the HIV infectivity, the glycoprotein gp120 on the HIV envelop must interact with CD4 and Heparan Sulfate (HS) proteoglycans on the surface of the host cells in order to enable HIV attachment, fusion and entry into these cells. In addition, the Trans-Activator Transcription (Tat), capable to enhance transcription and HIV virulence during infectivity, also binds to HS proteoglycans. The HS binding enables translocation of Tat proteins into the host cells. Certain chemokines and HS competitors such as exogenous glycosaminoglycans and other sulfated glycans, including those isolated from marine organisms, have been extensively studied as potential antiretroviral agents. This article is centered on revisiting the three above-mentioned functions of the sulfated glycans in the HIV infectivity and therapy: the essential roles played by HS in interactions with (1) gp120 during the HIV-host interaction, and (2) with Tat for its translocation into the host cells, and (3) the potential antiretroviral effects exerted by exogenous sulfated glycans of varying structures and origins.