Limitations of antiretroviral therapy (ART) include poor patient adherence, drug toxicities, viral resistance, and failure to penetrate viral reservoirs. Recent developments in nanoformulated ART (nanoART) could overcome such limitations. To this end, we now report a novel effect of nanoART that facilitates drug depots within intracellular compartments at or adjacent to the sites of the viral replication cycle. Poloxamer 407-coated nanocrystals containing the protease inhibitor atazanavir (ATV) were prepared by high-pressure homogenization. These drug particles readily accumulated in human monocyte-derived macrophages (MDM). NanoATV concentrations were~1,000 times higher in cells than those that could be achieved by the native drug. ATV particles in late and recycling endosome compartments were seen following pulldown by immunoaffinity chromatography with Rab-specific antibodies conjugated to magnetic beads. Confocal microscopy provided cross validation by immunofluorescent staining of the compartments. Mathematical modeling validated drug-endosomal interactions. Measures of reverse transcriptase activity and HIV-1 p24 levels in culture media and cells showed that such endosomal drug concentrations enhanced antiviral responses up to 1,000-fold. We conclude that late and recycling endosomes can serve as depots for nanoATV. The colocalization of nano- ATV at endosomal sites of viral assembly and its slow release sped antiretroviral activities. Long-acting nanoART can serve as a drug carrier in both cells and subcellular compartments and, as such, can facilitate viral clearance.
ASJC Scopus subject areas
- Insect Science