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Bosque, A.

Publications and source records attributed to Bosque, A..

2 recordsLinked to original sources
bioRxiv2021

The HIV latency reversal agent HODHBt enhances NK Cell effector and memory-like functions by increasing IL-15 mediated-STAT activation

Elimination of latent HIV reservoirs is a critical endpoint to eradicate HIV. One therapeutic intervention against latent HIV is shock and kill. This strategy is based on the transcriptional activation of latent HIV with a Latency-Reversing Agent (LRA) with the consequent killing of the reactivated cell by either the cytopathic effect of HIV or the immune system. We have previously found that the small molecule 3-Hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) act as an LRA by increasing Signal Transducers and Activators of Transcription (STAT) activation mediated by IL-15 in cells isolated from aviremic participants. The IL-15 superagonist (N-803) is currently under clinical investigation to eliminate latent reservoirs. IL-15 and N-803 share similar mechanism of action by promoting the activation STATs and have shown some promise in pre-clinical models directed towards HIV eradication. In this work, we evaluated the ability of HODHBt to enhance IL-15 signaling in NK cells and the biological consequences associated with increased STAT activation in NK effector and memory-like functions. We showed that HODHBt increased IL-15-mediated STAT phosphorylation in NK cells, resulting in increased secretion of CXCL10 and IFN-{gamma} and expression of cytotoxic proteins including Granzyme B, Granzyme A, Perforin, Granulysin, FASL and TRAIL. This increased cytotoxic profile results in an increase cytotoxicity against different tumor cell lines and HIV-infected cells. HODHBt also improved the generation of cytokine-induced memory-like NK cells. Overall, our data demonstrate that enhancing the magnitude of IL-15 signaling with HODHBt favors NK cell cytotoxicity and memory-like generation, and targeting this pathway could be further explored for HIV cure interventions. Author SummarySeveral clinical trials targeting the HIV latent reservoir with LRAs have been completed. In spite of a lack of clinical benefit of these trials, they have been crucial to elucidate hurdles that shock and kill strategies have to overcome to promote an effective reduction of the latent reservoir leading. These hurdles include low reactivation potential mediated by LRAs; the negative influence of some LRAs on the activity of Natural Killer and CD8T effector cells; an increased resistance to apoptosis of latently infected cells; and an exhausted immune system due to chronic inflammation. To that end, finding therapeutic strategies that can overcome some of these challenges could improve the outcome of shock and kill strategies aimed towards HIV eradication. In here, we showed that the LRA HODHBt also improves IL-15 mediated NK effector and memory-like functions. As such, pharmacological enhancement of IL-15 mediated STAT activation can open new therapeutic venues towards an HIV cure.

cell biology↗
bioRxiv2020

Selective BCL-XLAntagonists Eliminate Infected Cells from a Primary Cell Model of HIV Latency but not from Ex Vivo Reservoirs

HIV persists, despite antiviral immune responses and effective antiretroviral therapy, in viral reservoirs that seed rebound viremia if therapy is interrupted. Previously, we showed that the BCL-2 protein contributes to HIV persistence by conferring a survival advantage to reservoir-harboring cells. Here, we demonstrate that many of the BCL-2 family members are overexpressed in HIV-infected CD4+ T-cells, indicating increased tension between pro-apoptotic and pro-survival family members - as well as raising the possibility that the inhibition of pro-survival members may disproportionately affect the survival of HIV-infected cells. Based on these results, we chose to further study BCL2L1 (encoding the protein BCL-XL), due to its consistent overexpression and the availability of selective antagonists. Infection of primary CD4+ T-cells with either a clinical isolate, a CCR5-tropic strain, or a CXCR4-tropic strain of HIV resulted in increased BCL-XL protein expression; and treatment with two selective BCL-XL antagonists, A-1155463 and A-1551852, led to disproportionate cell death compared to uninfected CD4+ T-cells. In a primary cell model of latency, both BCL-XL antagonists drove significant reductions in total HIV DNA and in infectious cell frequencies both alone and in combination with the latency reversing agent bryostatin-1, with little off-target cytotoxicity. However, these antagonists, with or without bryostatin-1, or in combination with the highly potent latency reversing agent combination PMA + ionomycin, failed to reduce total HIV DNA and infectious reservoirs in ex vivo CD4+ T-cells from ART-suppressed donors. Our results add to growing evidence that bonafide reservoir-harboring cells are resistant to multiple "kick and kill" modalities - relative to latency models - and uncover BCL-XL antagonists as a facile approach to probing mechanistic underpinnings. We also interpret our results as encouraging of further exploration of BCL-XL antagonists for cure, where combination approaches may unlock the ability to eliminate ex vivo reservoirs.

microbiology↗