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Development of novel therapeutic strategies that reactivate latent HIV and sensitize reactivated cells to apoptosis is crucial towards elimination of the latent viral reservoir. Among the clinically relevant latency reversing agents (LRA) under investigation, the γc-cytokine IL-15 and the superagonist N-803 have been shown to reactivate latent HIV ex vivo and in vivo. However, their clinical benefit can be hindered by IL-15 promoting survival of infected cells. We previously identified a small molecule, HODHBt, that sensitizes latently infected cells to death upon reactivation with γc-cytokines through a STAT-dependent pathway. In here, we aimed to identify and evaluate FDA-approved compounds that could also sensitize HIV-infected cells to apoptosis. Using the Connectivity Map (CMap), we identified the retinol derivative 13-cis-retinoic acid (Isotretinoin) causes similar transcriptional changes as HODHBt. Isotretinoin enhances IL-15-mediated latency reversal without inducing proliferation of memory CD4 T cells. Ex vivo analysis of PBMCs from ACTG A5325, where Isotretinoin was administered to ART-suppressed people with HIV, showed that Isotretinoin treatment enhances IL-15-mediated latency reversal. Furthermore, we showed that a combination of IL-15 with Isotretinoin promotes the reduction of translation-competent reservoirs ex vivo. Mechanistically, combination of IL-15 and Isotretinoin increases caspase-3 activation specifically in HIV-infected cells but not uninfected cells. Our results suggest that Isotretinoin can be a novel approach to target and eliminate translation-competent HIV reservoirs. Author summary: Even with the development and rapid advancement of antiretroviral therapies (ART) against HIV in the past three decades, there is still no generalized cure for HIV. Identification of novel therapeutic interventions that target the latent reservoir could provide new avenues to find a cure. In this work, we evaluated the ability of the FDA-approved compound Isotretinoin to reactivate latent HIV and promote a reduction of the latent reservoir ex vivo. Our studies found that Isotretinoin can enhance the ability of IL-15 to reactivate latent reservoirs. Furthermore, using samples from clinical trial ACTG A5325 (NCT01969058) we show that Isotretinoin sensitizes latent HIV to reactivation by IL-15. Finally, we demonstrate that Isotretinoin can sensitize reactivated cells to death via apoptosis. Overall, this study demonstrate that Isotretinoin could be used in combinatorial strategies towards the development of an HIV cure to promote reduction of latent reservoirs. [ABSTRACT FROM AUTHOR]

Aim: To investigate Prussian blue nanoparticles (PBNPs) coated with the synthetic analog of dsRNA polyinosinic-polycytidylic acid (polyIC) for their ability to function as HIV latency reversing agents. Methods: A layer-by-layer method was used to synthesize polyIC-coated PBNPs (polyIC-PBNPs). PolyIC-PBNPs were stable and monodisperse, maintained the native absorbance properties of both polyIC and PBNPs and were obtained with high nanoparticle collection yield and polyIC attachment efficiencies. Results: PolyIC-PBNPs were more effective in reactivating latent HIV than free polyIC in a cell model of HIV latency. Furthermore, polyIC-PBNPs were more effective in promoting immune activation than free polyIC in CD4 and CD8 T cells. Conclusion: PBNPs function as efficient carriers of nucleic acids to directly reverse HIV latency and enhance immune activation. HIV is a virus that attacks and weakens the immune system. If left untreated, HIV infection leads to AIDS. To combat this, administration of antiretroviral therapy allows HIV to be controlled, and an infected individual may live a normal life. However, there is no cure for HIV because the virus persists within hidden reservoirs of latently infected cells that remain undetected by the immune system. A cure strategy currently under investigation in the field utilizes a latency reversing agent (LRA) to reactivate latent HIV with the goal of promoting a response from the immune system. To achieve this goal, this study used a nanoparticle-based method to administer LRAs. More specifically, the authors synthesized Prussian blue nanoparticles (PBNPs) coated with the LRA polyinosinic-polycytidylic acid (polyIC), a synthetic analog of dsRNA. This study demonstrates that when administered in the form of nanoparticles, polyIC-coated PBNPs generate both enhanced reactivation of HIV and immune activation when compared with free polyIC. These results indicate a promising potential for using PBNPs to deliver LRAs such as polyIC to enhance current and future HIV cure strategies. [ABSTRACT FROM AUTHOR]

The role of different biological variables including biological sex, age, and sex hormones in Human immunodeficiency virus (HIV) cure approaches is not well understood. The γc-cytokine IL-15 is a clinically relevant cytokine that promotes immune activation and mediates HIV reactivation from latency. In this work, we examined the interplay that biological sex, age, and sex hormones 17β-estradiol, progesterone, and testosterone may have on the biological activity of IL-15. We found that IL-15-mediated CD4+ T cell activation was higher in female donors than in male donors. This difference was abrogated at high 17β-estradiol concentration. Additionally, there was a positive correlation between age and both IL-15-mediated CD8+ T cell activation and IFN-γ production. In a primary cell model of latency, biological sex, age, or sex hormones did not influence the ability of IL-15 to reactivate latent HIV. Finally, 17β-estradiol did not consistently affect reactivation of translation-competent reservoirs in CD4+ T cells from people living with HIV who are antiretroviral therapy (ART) suppressed. Our study has found that biological sex and age, but not sex hormones, may influence some of the biological activities of IL-15. Understanding how different biological variables may affect HIV cure therapies will help us evaluate current and future clinical trials aimed toward HIV cure in diverse populations.

Nonreceptor tyrosine phosphatases (NTPs) play an important role in regulating protein phosphorylation and have been proposed as attractive therapeutic targets for cancer and metabolic diseases. We have previously identified that 3-Hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) enhanced STAT activation upon cytokine stimulation, leading to increased reactivation of latent HIV and effector functions of NK and CD8 T cells. Here, we demonstrate that HODHBt interacted with and inhibited the NTPs PTPN1 and PTPN2 through a mixed inhibition mechanism. We also confirm that PTPN1 and PTPN2 specifically controlled the phosphorylation of different STATs. The small molecule ABBV-CLS-484 (AC-484) is an active site inhibitor of PTPN1 and PTPN2 currently in clinical trials for advanced solid tumors. We compared AC-484 and HODHBt and found similar effects on STAT5 and immune activation, albeit with different mechanisms of action leading to varying effects on latency reversal. Our studies provide the first specific evidence to our knowledge that enhancing STAT phosphorylation via inhibition of PTPN1 and PTPN2 is an effective tool against HIV.

Assays to study HIV persistence are crucial to evaluate therapeutic strategies aimed toward an HIV cure. Several assays have been developed to date that rely on the measurement of nucleic acids. In recent years, the advancement of ultrasensitive technologies for the detection of proteins has improved our understanding of the role of translation-competent reservoirs in HIV persistence. In this chapter, we describe the development of an ultrasensitive p24 ELISA that uses planar array technology. This assay allows for the detection of HIV-1 p24 in the low fg/ml range in different biological matrixes, including cell lysates. This assay can be used to investigate the efficacy of latency reversing agents to reactivate HIV or to evaluate the persistence of translation-competent reservoirs in people living with HIV (PWH) in cells or diverse biological fluids., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Models to study HIV latency have improved our understanding of the mechanisms involved in this process and have helped in the discovery and development of therapeutic strategies to eradicate HIV. Primary cell models are based on the in vitro generation of latently infected cells using CD4T cells isolated from blood, lymph nodes or other lymphoid organs. In this chapter, we describe the generation of HIV latently infected memory CD4T cells using blood naïve CD4T cells from peripheral blood with a phenotype resembling that of central memory CD4T cells. This model can be used to investigate the mechanisms involved in latency as well to develop strategies to target it., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

HIV-specific T cells have diminished effector function and fail to control/eliminate the virus. IL-27, a member of the IL-6/IL-12 cytokine superfamily has been shown to inhibit HIV replication. However, whether or not IL-27 can enhance HIV-specific T cell function is largely unknown. In the present manuscript, we investigated the role of IL-27 signaling in human T cells by evaluating the global transcriptional changes related to the function of HIV-specific T cells. We found that T cells from people living with HIV (PLWH), expressed higher levels of STAT1 leading to enhanced STAT1 activation upon IL-27 stimulation. Observed IL-27 induced transcriptional changes were associated with IFN/STAT1-dependent pathways in CD4 and CD8 T cells. Importantly, IL-27 dependent modulation of T-bet expression promoted IFNγ secretion by TIGIT + HIV Gag -specific T cells. This new immunomodulatory effect of IL-27 on HIV-specific T cell function suggests its potential therapeutic use in cure strategies., Competing Interests: The authors declare no competing interests., (© 2021.)