HIV reactivation from latency - role of CD4 T cell maturation phenotype

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 DESCRIPTION (provided by applicant): The "shock and kill" treatment strategy has been envisioned as a controlled induction of virus reactivation in the presence of combination antiretroviral therapy (cART) to reveal latently infected cells for immune system recognition and destruction. Histone deacetylase inhibitors (HDACis) have potential for HIV reactivation in patients; however, further optimization of these strategies is needed to effectively reduce the size of latent reservoir. Emerging evidence from gene expression studies points to existence of secondary mechanisms of action of HDACis that may interfere with induction of HIV expression. Based on differences in the degree of HIV reactivation in response to HDACis in model systems that use different cell types, we propose that these inhibitory effects may vary among CD4+ T cells of different maturation phenotypes. The optimal reactivation strategy would be able to induce HIV expression from all CD4+ T cells with a minimal number of additional interventions; however, it is possible that maturation phenotype-specific interventions would be required. The objective of this proposal is to identify host genes and proteins modulated by HDACis in CD4+ T cells of various maturation phenotypes that can be therapeutically targeted to enhance the activation effect of HDACis. The central hypothesis is that HIV is reactivated by HDACis with different potencies and via different mechanisms depending on CD4+ T cell maturation state, and that reactivation may be augmented by counteracting the secondary effects of HDACis that interfere with HIV expression. The rationale for this study is to improve on existing strategies for HIV reactivation by identifying possible targets to counteract inhibitory effects of HDACis across cells of all majo maturation phenotypes to ensure HIV eradication from the entire CD4+ T cell reservoir. To achieve our goals, we will measure induction of HIV expression in naïve, central memory and effector memory cells using the in vitro latency model developed by Dr. Spina. We will then characterize global gene and protein expression changes induced by HDACis by methods of RNA-Seq and liquid chromatography mass spectrometry (LC-MS), and identify effects that may specifically interfere with HIV expression in CD4+ T cell subsets. Based on RNA-Seq and LC-MS data, a set of targets will be selected for validation studies, including validating changes in expression in a time course and in another latency model (developed by Dr. Karn), and knockdown / overexpression studies in the presence of HDACi to test for synergy. The expected positive impact of this work is identification of therapeutic candidates with strong potential to improve HIV reactivation currently achieved. Dr. Beliakova-Bethell will work with one primary mentor and three co-mentors, who are leaders in the field of HIV research. Exposure to a collaborative and diverse scientific environment, as part of the VA Healthcare System HIV research group, as well as the Center for AIDS Research at the University of California San Diego, will advance her career development. Her long-term career goal is to become a leader in the field of HIV-host interactions, HIV latency and immunology, and a successful VA scientist. During the period of the award, she will focus on obtaining training in: (1) HIV latency and human immunology; (2) proteomics; (3) translational research; and on developing skills necessary to build a solid, independently funded clinically relevant research career. To accomplish these goals, her career plan includes regular interactions with mentors, participation in specific didactic courses in career development, and acquiring expertise in new experimental techniques. Her mentors will help her establish a professional network through introductions to collaborators and will support transitioning to an independent career by serving as co-investigators on future grant proposals. Dr. Beliakova-Bethell will be well suited for independent research career within the VA System, with research focused in areas of importance to the VA.