The effect of latency reversal agents (LRA) on type I interferon signaling in immune cells from people living with HIV
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Abstract
INTRODUCTION: Human Immunodeficiency Virus-1 infection has remained a global health challenge for over the past 40 years. Although combination therapies exist to reduce viremia to undetectable levels in HIV-1-positive individuals, these are costly and require lifelong adherence, causing many researchers to push for the development of an HIV-1 cure. The major obstacle to an HIV-1 cure is the presence of a latent viral reservoir that is undetectable by the host immune system. One approach to a cure is using latency reversal agents to reactivate latent HIV so it may be detected and cleared by immune effector cells. Thus, it is critically important to understand the effect of latency reversal agents on the functionality of the innate immune system, including type I interferon signaling, which is responsible for inducing antiviral effects within the cell. In addition, biological sex differences in type I interferon signaling have been reported and require further investigation. Therefore, this paper aims to investigate the effect of latency reversal agents on type 1 interferon-stimulated gene signaling in both uninfected and HIV-positive individuals and evaluate expression differences between men and women.
METHODS: CD4+ T cells from a total of 5 uninfected donors (2 males, 3 females) and 5 HIV-1-positive donors (3 males, 2 females) were isolated from PBMCs and evaluated for expression of various interferon-stimulated genesfollowing treatment with various classes of latency reversal agents (LRAs). Exposure to IFN𝛼 was used as positive control. Random selection was employed to include cells from individuals of both biological sexes. This study was performed using biosafety level 2 (BSL-2) and biosafety level 2+ (BSL-2+) standard practices and precautions.
RESULTS: Data collected from CD4+ cells from the 5 uninfected donors indicated that treatment with positive control IFN𝛼 was correlated with higher ISG56, IRF7, and IFI6 gene expression compared to untreated CD4+ cells (p < 0.05). Treatment of uninfected CD4+ T cells with PEP005 was correlated with an overall decrease in ISG56 expression and increase in ISG15 expression compared to untreated controls (p < 0.05). Treatment of uninfected CD4+ T cells with VOR did not yield a significant difference in ISG expression compared to untreated controls. In HIV-positive CD4+ T cells, treatment with PEP005 was correlated with an overall increase in IRF7, IFI27, and IFI16 expression compared to untreated, HIV-positive CD4+ cells. Treatment of HIV-positive CD4+ T cells with VOR did not yield a significant difference in ISG expression compared to untreated, HIV-positive controls. Further analysis is required to confirm these preliminary data trends in ISG expression in HIV-positive CD4+ cells.
CONCLUSION: Although the results indicate the ability of IFN𝛼, VOR, and PEP005 to modulate ISG expression in CD4+ cells from HIV-negative individuals, more donors are required to confirm these preliminary results, as well as elucidate the relationship of biological sex on LRA exposure and ISG expression. Furthermore, more samples from HIV-1-positive individuals are required to compare ISG expression between uninfected and virally infected individuals. Future directions of this study aim to include more donor samples, evaluate ISG expression in other immune effector cells such as NK cells, CD8+ T cells, and pDCs, confirm ISG translation into detectable protein via Western blot analysis, and characterize the effect of other LRAs on ISG expression.
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2024