Objective: Although HAART effectively suppresses viral replication, it fails to eradicate latent viral reservoirs. The ‘shock and kill’ strategy involves the activation of HIV from latent reservoirs and targeting them for eradication. Our goal was to develop new approaches for activating HIV from latent reservoirs.
Design: We investigated capacity of Ingenol B (IngB), a newly modified derivative of Ingenol ester that was originally isolated from a Brazilian plant in Amazon, for its capacity and mechanisms of HIV reactivation.
Methods: Reactivation of HIV-1 by IngB was evaluated in J-Lat A1 cell culture model of HIV latency as well as in purified primary CD4+ T cells from long-term HAART-treated virologically-suppressed HIV-infected individuals. The underlining molecular mechanisms of viral reactivation were investigated using flow cytometry, RT-qPCR and chromatin immunoprecipitation.
Results: IngB is highly effective in reactivating HIV in J-Lat A1 cells with relatively low cellular toxicity. It is also able to reactivate latent HIV in purified CD4+ T cells from HAART-treated HIV-positive individuals ex vivo. Our data show that IngB may reactivate HIV expression by both activating protein kinase C (PKC)δ–nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway and directly inducing NF-κB protein expression. Importantly, IngB has a synergistic effect with JQ1, a BET bromodomain inhibitor, in latent HIV reactivation.
Conclusions: IngB is a new promising compound to activate latent HIV reservoirs. Our data suggest that formulating novel derivatives from Ingenol esters may be an innovative approach to develop new lead compounds to reactivate latent HIV.
aDepartment of Medical Microbiology & Immunology, University of California, Davis
bSection of Infectious Diseases, Department of Medicine, University of California, San Francisco
cDepartment of Molecular & Cellular Biology
dDepartment of Internal Medicine, Division of Infectious Diseases, University of California, Davis, California, USA
eInstitute of Biology and Department of Genetics, UFRJ Rio de Janeiro
fKyoLab, Valinhos, São Paulo, Brazil.
*Guochun Jiang and Erica A. Mendes contributed equally to the writing of this article.
Correspondence to Satya Dandekar, Department of Medical Microbiology and Immunology, University of California, Davis, CA 95616, USA. E-mail: firstname.lastname@example.org
Received 6 December, 2013
Revised 25 March, 2014
Accepted 27 March, 2014