HSV-2 triggers upregulation of MALAT1 in CD4+ T cells and promotes HIV latency reversal

Abstract

HSV-2 coinfection is associated with increased HIV-1 viral loads and expanded tissue reservoirs, but the mechanisms are not well-defined. HSV-2 recurrences result in an influx of activated CD4+ T cells to sites of viral replication and an increase in activated CD4+ T cells in peripheral blood. We hypothesized that HSV-2 induces changes in these cells that facilitate HIV-1 reactivation and replication and tested this hypothesis in human CD4+ T cells and 2D10 cells, a model of HIV-1 latency. HSV-2 promoted latency reversal in HSV-2 infected and bystander 2D10 cells. Bulk and single-cell RNA sequencing studies of activated primary human CD4+ T cells identified decreased expression of HIV-1 restriction factors and increased expression of transcripts including MALAT1 that could drive HIV replication in both the HSV-2-infected and bystander cells. Transfection of 2D10 cells with VP16, an HSV-2 protein that regulates transcription, significantly upregulated MALAT1 expression, decreased trimethylation of lysine 27 on histone H3 protein, and triggered HIV latency reversal. Knockout of MALAT1 from 2D10 cells abrogated the response to VP16 and reduced the response to HSV-2 infection. These results demonstrate that HSV-2 contributes to HIV-1 reactivation through diverse mechanisms including upregulation of MALAT1 to release epigenetic silencing. Brief summary: HSV-2 triggers transcriptional changes in CD4+ T cells including upregulation of the long noncoding RNA MALAT to promote HIV reactivation and replication.frequency of CCR5+, CXCR4+, PD-1+, and CD69+ and decreased frequency of CCR10+ and CCR6+ CD4+ T-cells. These changes were associated with higher levels of cell-associated HIV-1 DNA. Paradoxically, IL-32, a proinflammatory cytokine, was lower in subpopulations of CD4+ T-cells in HSV-2 + versus HSV-2women and the addition of recombinant IL-32γ blocked HIV reactivation in CD4+ T-cells treated with phytohemagglutinin (PHA) (12,13). Other studies found that siRNA targeting IL-32 resulted in an increase in HIV replication (13). Together these findings suggested that the phenotypic changes in CD4+ T cells including the decrease in IL-32γ associated with HSV-2 may promote HIV-1 reactivation and/or replication. However, the molecular mechanisms underlying these changes and their effects on HIV-1 reactivation are not known.Activated CD4+ T cells are susceptible to HSV-2 infection in vitro ( 14) and virus has been detected in CD4+ T cells isolated from vesicle fluid of genital lesions and within biopsies of HSV-2 skin lesions (15). The recruitment and persistence of activated CD4+ T cells to the genital mucosa during HSV-2 reactivation (5) and potential for activated peripheral blood CD4+ T cells to be exposed to HSV during episodes of transient prompted us to postulate that HSV-2 might have direct or indirect bystander effects on CD4+ T cells to promote HIV-1 reactivation and/or replication. We therefore analyzed the effects of HSV-2 infection of activated primary CD4+ T cells and an immortalized human CD4+ T cell line model o...

Targeting noncoding RNAs to reactivate or eliminate latent HIV reservoirs

“…Consistent with these observations, a recent study reported upregulation of MALAT1 concomitant with HIV reactivation in 2D10 cells by another HDACi, romidepsin [33 ▪ ]. When MALAT1 was knocked out, the ability of romidepsin to induce latency reversal in 2D10 cells was reduced [33 ▪ ].…”

“…An example of LRAs inducing HIV reactivation, in part, via modulation of ncRNAs is the upregulation of MALAT1 with the concomitant reduction of the LTR occupancy by EZH2 following treatment with either phytohemagglutinin-P (PHA-P) or SAHA [42]. Consistent with these observations, a recent study reported upregulation of MALAT1 concomitant with HIV reactivation in 2D10 cells by another HDACi, romidepsin [33 ▪ ]. When MALAT1 was knocked out, the ability of romidepsin to induce latency reversal in 2D10 cells was reduced [33 ▪ ].…”

“…Unfortunately, basic studies investigating ncRNA mechanisms of action highly rely on cell lines and do not consider individual cell subsets when using primary cells. Of the 32 mechanistic studies investigating ncRNA function (Table 1), the majority were conducted using T cell ( N = 28 studies [15–42]) or monocytic ( N = 4 studies [43,44 ▪▪ ,45,46]) cell lines. In ten studies [15–24], there were no experiments that used primary cells.…”

“…In ten studies [15–24], there were no experiments that used primary cells. In ten studies [25–34], ncRNA expression was detected and characterized in primary cells during viral infection; in seven studies [35–41] experimental manipulation (e.g. knockdown or overexpression) of ncRNAs was shown to affect HIV in primary cells.…”

Purging viral latency by a bifunctional HSV-vectored therapeutic vaccine in chronically SIV-infected macaques

“…Significantly, epidemiological research suggests a synergistic effect between HSV and HIV infections, with HSV infection in HIV patients being associated with increased HIV-1 viral load and disease progression (Looker et al, 2017, Calistri et al, 2003, Heng et al, 1994). Some studies have further unveiled the ability of HSV to activate HIV latent reservoirs (Amici et al, 2004, Amici et al, 2001, Pierce et al, 2023). Given the potential of HSV to simultaneously induce antigen-specific immune responses and reactivate latent viral reservoirs, we propose a proof-of-concept strategy to achieve an HIV functional cure using a modified bifunctional HSV-vectored therapeutic vaccine.…”