PROJECT SUMMARY/ABSTRACT HIV remains a global threat despite the tremendous progress of combinatorial antiretroviral therapy (cART). Chronic inflammation and immune activation support an increased risk of non-AIDS co-morbidities in cART- treated HIV patients. This condition is attributed to various factors including antiretroviral (ARV) toxicity and viral persistence in secondary lymphoid tissues (SLTs) which has been linked to low ARV penetration in these reservoir sites. Furthermore, uptake of daily antiretrovirals (ARVs) remains a burden resulting in poor adherence that can lead to viral rebound from the SLTS. In this project, we propose to develop a long-acting “stealth” nanoformulation composed of lipid wrapped poly-lactic acid nanoparticles (GM3-PLA-NPs) loaded with a non-nucleoside reverse transcriptase inhibitor, Rilpivirine (RPV) and integrase inhibitor, Cabotegravir (CAB). These GM3-PLA-NPs have innovative targeting and design features that will increase drug entry and retention in SLTs, in addition to modulating inflammatory responses. Indeed, the membrane incorporated monosialo di-hexosylganglioside (GM3) enables specific binding to the sialic acid lectin receptor CD169 on myeloid cells (macrophages and dendritic cells), leading to the formation of non-acidic membrane invaginations which can prevent NP degradation, and lead to long-term establishment of cellular drug depots. These NP collecting compartments (NPCCs) are identical to the previously defined virus containing compartments (VCCs) formed upon capture of HIV-1 by CD169. Since VCCs are also involved in myeloid cell- mediated HIV transmission to CD4+ T cells (trans-infection) through the virological synapse, I hypothesize that NPCCs could potentially promote sustained ARV release to bystander T cells through macrophage – T cell synaptic junctions. Our preliminary data have demonstrated that these GM3-PLA-NPs are successfully preserved in NPCCs of CD169+ macrophages over time which extended anti-viral potency in these cells for a month in vitro. Subsequently, sustained viral inhibition in bystander Jurkat T cells was observed upon co- culture with NP-exposed CD169+ macrophages. Additionally, our findings suggest that the GM3 lipid coating confers “stealth” properties to suppress non-specific immune activation induced by loaded ARVs and nanoparticle core. Thus, in aim 1, we will investigate the extracellular drug release mechanism from CD169+ macrophages to CD4+ T cells. In aim 2, we will assess the long-term toxicity and stealth mechanism of GM3- PLA-NPs. Finally, we will confirm these results in vivo by assessing the spatial distribution and stealth phenotype of GM3-PLA-NPs in SLTs in aim 3. These studies will elucidate a new approach for safe and effective delivery of long-acting therapeutics to SLTs which could be beneficial for HIV prevention and treatment as well as other diseases such as metastatic cancer.

Project Narrative Viral persistence due to low antiretroviral (ARV) penetration in secondary lymphoid tissues (SLTs) and poor adherence to daily ARV regimen remain major barriers to achieving a functional cure for HIV. We want to develop “stealth” long-acting lipid polymeric nanoparticles (GM3-PLA-NPs) that can potentially increase ARV entry and retention in SLTs by forming cellular drug depots in CD169+ macrophages. Our proposed studies will investigate the stealth and biodistribution mechanisms of GM3-PLA-NPs to elucidate new strategies for targeted delivery of safe long-acting drugs in the SLTs and hence aid in the development of nanotherapeutics for prevention and treatment of HIV.