Gesicles packaging dCas9-VPR ribonucleoprotein complexes can combine with vorinostat and promote HIV proviral transcription.

Abstract

Despite the success of combination antiretroviral therapies (cART) in HIV treatment, a cure for HIV remains elusive. Scientists postulate that HIV latent reservoirs may be a vital target in curative strategies. Vorinostat is a latency-reversing agent which has demonstrated some effectiveness in reactivating latent HIV, but complementary therapies may be essential to enhance its efficacy. One such approach may utilize the CRISPR/Cas9 system which has evolved to include transcriptional activators such as dCas9-VPR. In this study, we explored the effects of combining vorinostat coupled with gesicle-mediated delivery of dCas9-VPR in promoting the transcription of integrated HIV proviruses in HIV-NanoLuc CHME-5 microglia and J-Lat 10.6 lymphocytes. We confirmed that dCas9-VPR ribonucleoprotein complexes can be packaged into gesicles and application to cells successfully induced HIV transcription through interactions with the HIV LTR. Vorinostat also induced significant increases in proviral transcription but generated inhibition of cellular proliferation (microglia) or cell viability (lymphocytes) starting at 1000nM and higher concentrations. Experiments combining dCas9-VPR gesicles and vorinostat confirmed the enhanced transcriptional activation of the HIV provirus in microglia but not lymphocytes. Thus, a combination of dCas9-VPR gesicles with other latency reversing agents may provide a complementary method to activate latent HIV in future studies utilizing patient-derived cells or small animal models.