DNA-PK inhibition to abolish HIV gene products - Project Summary: Despite years of effective antiretroviral therapy (ART), people living with HIV (PLWH) still experience persistent residual inflammation and immune activation. This is due to the fact that ART regimens lack transcriptional inhibitors, making ART unable to fully control HIV gene expression. Consequently, the continuous presence of HIV RNA and proteins contributes to a chronic inflammatory state, even when viral replication is fully suppressed. The ultimate long-term goal is to develop novel strategies and therapeutics to eliminate HIV transcripts and proteins, thereby reducing persistent immune activation and inflammation in PWH, even under effective ART. We discovered the essential role of DNA-dependent protein kinase (DNA-PK) in supporting HIV transcription, replication, and latency reactivation. Consequently, we found that partial DNA-PK inhibition, using less than one-fifth amount of in-human tested DNA-PK inhibitor (DNA-PKi), as cancer therapeutics, was sufficient to restrict HIV transcription without any cell toxicity in patients’ PBMCs, suggesting the therapeutic value of DNA- PKi. The objective of this grant is to establish the safety and therapeutic potential of in-human-tested DNA-PKi. Based on our several publications on this subject, we have hypothesized that partial DNA-PK inhibition, using clinically evaluated DNA-PKi, will profoundly suppress HIV transcription, but moderate in affecting cellular gene expression and physiology. In Aim 1, we will assess the impact of two highly specific and clinically evaluated DNA-PKi in restricting HIV transcription; besides regulation of host cell gene expression to assess cell toxicity due to HIV gene products. In Aim 2, using a well-characterized HIV infected humanized mouse model, we will evaluate the therapeutic value of DNA-PKi in restricting HIV transcription, viral load, and rebound, and limit HIV reservoir; thus, protecting cells from the toxicity of HIV gene products. Upon conclusion of the study, we will establish the translational potential of DNA-PKi in limiting HIV gene expression, viral load and reservoir, besides restricting comorbidities associated with HIV gene products, including immune activation and inflammation. Our rationale is that since latency is primarily regulated at the transcriptional level, mechanism(s) that regulate HIV transcription will not only offer new therapeutic avenues to target HIV reservoirs, but also to reduce the downstream chronic health complications of PLWH on ART, such as inflammation and immune activation. Proposed research is innovative because the study will test a well-defined therapeutic target in the form of DNA-PK, and this new knowledge will be valuable for both basic and translational research. This contribution is significant, since we will test the clinical relevance of DNA-PK inhibitors in restricting HIV gene expression, besides viral load and rebound upon ART interruption. This analysis will enable the designing of optimized therapies targeting HIV gene expression and their associated comorbidities in PLWH under effective ART. Additionally, while providing the Proof-of concept, the study will demonstrate the feasibility of partially inhibiting DNA-PK as an effective and safe means to suppress HIV transcription; thus, contributing to cure approaches.
