A histone deacetylase network regulates epigenetic reprogramming and viral silencing in HIV infected cells

Approximately 70% of the HIV-1 latent reservoir originates from infections of CD4 T cells that occur in the months near the time of ART initiation, raising the possibility that interventions during this period might prevent reservoir seeding and reduce reservoir size. We identify class 1 histone deacetylase inhibitors (HDACi) as potent agents of latency prevention. Inhibiting HDACs in productively infected cells caused extended maintenance of HIV expression and this activity was associated with persistently elevated H3K9 acetylation and reduced H3K9 methylation at the viral LTR promoter region. HDAC inhibition in HIV-infected CD4 T cells during effector-to-memory transition led to striking changes in the memory phenotype of infected cells. Proviral silencing is accomplished through distinct activities of HDAC1/2 and HDAC3. Thus HDACs regulate a critical gateway process for HIV latency establishment and are required for the development of CD4 T-cell memory subsets that preferentially harbor long-lived, latent provirus.