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Reactivation of the latent HIV-1 reservoir is a first step toward triggering reservoir decay. Here, we investigated the impact of the BAF complex inhibitor pyrimethamine on the reservoir of people living with HIV-1 (PLWH). Twenty-eight PLWH on suppressive antiretroviral therapy were randomized (1:1:1:1 ratio) to receive pyrimethamine, valproic acid, both, or no intervention for 14 days. The primary end point was change in cell-associated unspliced (CA US) HIV-1 RNA at days 0 and 14. We observed a rapid, modest, and significant increase in (CA US) HIV-1 RNA in response to pyrimethamine exposure, which persisted throughout treatment and follow-up. Valproic acid treatment alone did not increase (CA US) HIV-1 RNA or augment the effect of pyrimethamine. Pyrimethamine treatment did not result in a reduction in the size of the inducible reservoir. These data demonstrate that the licensed drug pyrimethamine can be repurposed as a BAF complex inhibitor to reverse HIV-1 latency in vivo in PLWH, substantiating its potential advancement in clinical studies.

HIV-1 infection remains non-curative due to the latent reservoir, primarily a small pool of resting memory CD4+ T cells bearing replication-competent provirus. Pharmacological reversal of HIV-1 latency followed by intrinsic or extrinsic cell killing has been proposed as a promising strategy to target and eliminate HIV-1 viral reservoirs. Latency reversing agents have been extensively studied for their role in reactivating HIV-1 transcription in vivo , although no permanent reduction of the viral reservoir has been observed thus far. This is partly due to the complex nature of latency, which involves strict intrinsic regulation at multiple levels at transcription and RNA processing. Still, the molecular mechanisms that control HIV-1 latency establishment and maintenance have been almost exclusively studied in the context of chromatin remodeling, transcription initiation and elongation and most known LRAs target LTR-driven transcription by manipulating these. RNA metabolism is a largely understudies but critical mechanistic step in HIV-1 gene expression and latency. In this review we provide an update on current knowledge on the role of RNA processing mechanisms in viral gene expression and latency and speculate on the possible manipulation of these pathways as a therapeutic target for future cure studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Crespo, Rao and Mahmoudi.)

A major pharmacological strategy toward HIV cure aims to reverse latency in infected cells as a first step leading to their elimination. While the unbiased identification of molecular targets physically associated with the latent HIV-1 provirus would be highly valuable to unravel the molecular determinants of HIV-1 transcriptional repression and latency reversal, due to technical limitations, this has been challenging. Here we use a dCas9 targeted chromatin and histone enrichment strategy coupled to mass spectrometry (Catchet-MS) to probe the differential protein composition of the latent and activated HIV-1 5'LTR. Catchet-MS identified known and novel latent 5'LTR-associated host factors. Among these, IKZF1 is a novel HIV-1 transcriptional repressor, required for Polycomb Repressive Complex 2 recruitment to the LTR. We find the clinically advanced thalidomide analogue iberdomide, and the FDA approved analogues lenalidomide and pomalidomide, to be novel LRAs. We demonstrate that, by targeting IKZF1 for degradation, these compounds reverse HIV-1 latency in CD4+ T-cells isolated from virally suppressed people living with HIV-1 and that they are able to synergize with other known LRAs., (© The Author(s) 2022. Published by Oxford University Press on behalf of Nucleic Acids Research.)

To identify novel host factors as putative targets to reverse HIV-1 latency, we performed an insertional mutagenesis genetic screen in a latent HIV-1 infected pseudohaploid KBM7 cell line (Hap-Lat). Following mutagenesis, insertions were mapped to the genome, and bioinformatic analysis resulted in the identification of 69 candidate host genes involved in maintaining HIV-1 latency. A select set of candidate genes was functionally validated using short hairpin RNA (shRNA)-mediated depletion in latent HIV-1 infected J-Lat A2 and 11.1 T cell lines. We confirmed ADK, CHD9, CMSS1, EVI2B, EXOSC8, FAM19A, GRIK5, IRF2BP2, NF1, and USP15 as novel host factors involved in the maintenance of HIV-1 latency. Chromatin immunoprecipitation assays indicated that CHD9, a chromodomain helicase DNA-binding protein, maintains HIV-1 latency via direct association with the HIV-1 5' long terminal repeat (LTR), and its depletion results in increased histone acetylation at the HIV-1 promoter, concomitant with HIV-1 latency reversal. FDA-approved inhibitors 5-iodotubercidin, trametinib, and topiramate, targeting ADK, NF1, and GRIK5, respectively, were characterized for their latency reversal potential. While 5-iodotubercidin exhibited significant cytotoxicity in both J-Lat and primary CD4 + T cells, trametinib reversed latency in J-Lat cells but not in latent HIV-1 infected primary CD4 + T cells. Importantly, topiramate reversed latency in cell line models, in latently infected primary CD4 + T cells, and crucially in CD4 + T cells from three people living with HIV-1 (PLWH) under suppressive antiretroviral therapy, without inducing T cell activation or significant toxicity. Thus, using an adaptation of a haploid forward genetic screen, we identified novel and druggable host factors contributing to HIV-1 latency. IMPORTANCE A reservoir of latent HIV-1 infected cells persists in the presence of combination antiretroviral therapy (cART), representing a major obstacle for viral eradication. Reactivation of the latent HIV-1 provirus is part of curative strategies which aim to promote clearance of the infected cells. Using a two-color haploid screen, we identified 69 candidate genes as latency-maintaining host factors and functionally validated a subset of 10 of those in additional T-cell-based cell line models of HIV-1 latency. We further demonstrated that CHD9 is associated with HIV-1's promoter, the 5' LTR, while this association is lost upon reactivation. Additionally, we characterized the latency reversal potential of FDA compounds targeting ADK, NF1, and GRIK5 and identify the GRIK5 inhibitor topiramate as a viable latency reversal agent with clinical potential.

An innovative approach to eliminate HIV-1-infected cells emerging out of latency, the major hurdle to HIV-1 cure, is to pharmacologically reactivate viral expression and concomitantly trigger intracellular pro-apoptotic pathways in order to selectively induce cell death (ICD) of infected cells, without reliance on the extracellular immune system. In this work, we demonstrate the effect of DDX3 inhibitors on selectively inducing cell death in latent HIV-1-infected cell lines, primary CD4+ T cells and in CD4+ T cells from cART-suppressed people living with HIV-1 (PLWHIV). We used single-cell FISH-Flow technology to characterise the contribution of viral RNA to inducing cell death. The pharmacological targeting of DDX3 induced HIV-1 RNA expression, resulting in phosphorylation of IRF3 and upregulation of IFNβ. DDX3 inhibition also resulted in the downregulation of BIRC5, critical to cell survival during HIV-1 infection, and selectively induced apoptosis in viral RNA-expressing CD4+ T cells but not bystander cells. DDX3 inhibitor treatment of CD4+ T cells from PLWHIV resulted in an approximately 50% reduction of the inducible latent HIV-1 reservoir by quantitation of HIV-1 RNA, by FISH-Flow, RT-qPCR and TILDA. This study provides proof of concept for pharmacological reversal of latency coupled to induction of apoptosis towards the elimination of the inducible reservoir.

Men who have sex with men (MSM) and transgender women (TGW) are highly affected by HIV and need novel prevention strategies. Using HIV self-testing (HIVST) kits to screen sexual partners may represent a viable risk-reduction alternative; however, more research is needed on effective strategies for broaching HIVST with partners. In the ISUM study, 136 MSM and TGW were given ten HIVST kits for self- and partner-testing. After 3 months, they returned for a follow-up assessment; thirty participants were also selected for in-depth interviews about their experiences initiating HIVST with partners. Most found proposing HIVST to a diverse array of partners relatively easy. They employed strategies such as joint testing and integrating HIVST into larger discussions about protection and sexual health, with moderate success. Nonetheless, real or anticipated negative partner reactions were a significant barrier. Future research can inform best practices for safely and successfully broaching HIVST with sexual partners.

For those most at risk of contracting HIV, new strategies for preventing transmission and increasing testing are needed. As part of a multi-site, randomized, controlled trial, we explored attitudes and preferences among 272 HIV-negative men who have sex with men and HIV-negative transgender women using an HIV self-testing (HIVST) kit to test partners. Less than one quarter had previously self-tested with HIVST kits (21.7%) and few had partner-tested (4.8%). Most preferred gum swab (96%) over fingerprick tests (69%), but would prefer a blood test if it gave results for other sexually transmitted infections (STIs) (86%). Five percent reported difficulties performing the test, four percent with storage, and 26% with portability. Ninety-three percent reported likelihood of using HIVST to test partners in future, but only 3% were willing to pay the current price. Efforts to improve HIVST uptake should focus on incorporating testing for other STIs, reducing test kit size, and reducing cost.

Two constructs from the information-motivation-behavioral skills model were used to predict HIV-serostatus among a sample of men and transgender women who have sex with men. Hypotheses were that lower levels of HIV knowledge and lower levels of motivation to remain HIV-negative would be associated with an increased likelihood of receiving a positive HIV test result at a study eligibility-screening session. Results of a backwards stepwise logistic regression analysis demonstrated that lower levels of HIV knowledge, lower levels of motivation to remain HIV-negative, lower levels of education, and identifying as Hispanic/Latinx were associated with greater odds of receiving a positive HIV test result. These findings are consistent with the broader HIV-prevention literature that demonstrates that information and motivation are fundamental determinants of HIV preventive behavior. This work has implications for informing the development and improvement of HIV-prevention interventions.

Secondary distribution of HIV self-tests to sexual partners is acceptable but concerns remain about reactions if a partner tests HIV-positive. We report on 14 participants whose sexual partners tested HIV-positive during the "I'll Show You Mine" Study, a randomized controlled trial (N = 272) of HIV self- and partner-testing among men who have sex with men (MSM) and transgender women (TGW). All 14 were MSM and racial/ethnic minorities, mean age was 36.6 years; 86% were gay-identified. Twenty-four partners tested positive; about half were new partners. Six participants had multiple partners test positive. During in-depth interviews with 10 of these participants, they reported their partners' reactions ranged from tearful and worried among those whose result was unexpected, to resignation among those who suspected a positive result, to nonchalance among partners who participants concluded knew of their HIV infection. After testing, some HIV-positive partners disclosed prior knowledge of their status. No partner reacted violently. Participants typically comforted their partners and encouraged confirmatory testing. Four participants had anal intercourse with partners who tested positive. Participants and partners were able to effectively handle situations in which the partner tested HIV-positive.

HIV partner-testing (PT) may represent a unique and empowering HIV prevention strategy for groups that face structural and institutional barriers to HIV testing and care, including transgender women. We report on in-depth interviews (IDIs) with N = 10 transgender women who used HIV self-test kits for three months to screen potential sexual partners in a randomized controlled trial (iSUM; "I'll Show You Mine") that took place in New York City and San Juan, Puerto Rico. Participants were assigned to intervention (supplied with 10 self-test kits immediately) or control groups (received 6 test kits after 3 months). We conducted IDIs with the first N = 10 transgender women to enroll in the intervention group after three months in the study (after participants used kits with partners) to understand their experiences. Themes discussed in IDIs included: partners' reaction to HIV testing, participants' reactions to partners' test results or refusal to test, partners' own reaction to their test results, and decision-making around test use. Data were independently analyzed by two coders. Overwhelmingly, participants' experiences with PT was positive. Participants reported kits were convenient and acceptable to most partners. Transgender women felt that PT could pose additional risk for them; one woman experienced violence related to kit use. Furthermore, the availability of kits appeared to encourage participants and their partners to think about their HIV status and, in some cases, modify sexual behavior. Work suggests that HIV PT could be a viable risk-reduction strategy for transgender women.

A leading pharmacological strategy toward HIV cure requires "shock" or activation of HIV gene expression in latently infected cells with latency reversal agents (LRAs) followed by their subsequent clearance. In a screen for novel LRAs, we used fungal secondary metabolites as a source of bioactive molecules. Using orthogonal mass spectrometry (MS) coupled to latency reversal bioassays, we identified gliotoxin (GTX) as a novel LRA. GTX significantly induced HIV-1 gene expression in latent ex vivo infected primary cells and in CD4 + T cells from all aviremic HIV-1 + participants. RNA sequencing identified 7SK RNA, the scaffold of the positive transcription elongation factor b (P-TEFb) inhibitory 7SK small nuclear ribonucleoprotein (snRNP) complex, to be significantly reduced upon GTX treatment of CD4 + T cells. GTX directly disrupted 7SK snRNP by targeting La-related protein 7 (LARP7), releasing active P-TEFb, which phosphorylated RNA polymerase II (Pol II) C-terminal domain (CTD), inducing HIV transcription., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

ISUM ("I'll show you mine") was a randomized controlled trial in which 272 transgender women and men who have sex with men in New York, NY (NYC) and San Juan, Puerto Rico (SJU) were assigned to an intervention group (n = 136), in which they had access to free HIV self-testing (ST) kits, or to a control group (n = 136). The trial aimed to determine whether the intervention group would use ST to screen sexual partners and have fewer condomless anal intercourse (CAI) occasions with serodiscordant or unknown status partners than the control group. The intervention group had on average 10 (32%) fewer CAI occasions; though clinically relevant, this difference fell short of statistical significance (p = .08). In NYC (n = 166) intervention participants had significantly fewer CAI occasions, whereas in SJU (n = 106) they reported non-significantly more CAI occasions. Two devastating hurricanes hit SJU during the study and may have impacted results in unmeasured ways.

Transgender female sex workers (TFSW) are highly affected by HIV, with a global prevalence of 27%. HIV self-testing (HIVST) to screen sexual partners has helped men who have sex with men and female sex workers make informed sexual decisions and avoid HIV exposure. This is the first report on TFSW's experiences screening clients using HIVST. Ten TFSW were each given ten HIVST kits and returned after 3 months to complete an online questionnaire and undergo an interview. Eight of them reported using HIVST with potential partners. Among fifty potential partners who were asked in person to test, 42 (84%) were clients. Thirty-four out of fifty (68%) accepted and 16 (32%) refused. Very few violent incidents occurred, and participants felt empowered by offering HIVST to others. Nevertheless, HIVST market cost was prohibitive for future use. HIVST use with clients could be feasible for TFSW if the cost were lowered or subsidized.

Men who have sex with men and transgender women are hard-to-reach populations for research. Social media-based tools may overcome certain barriers in accessing these groups and are being tested in an ongoing study exploring HIV home-test kit use to reduce risk behavior. We analyzed pre-screening responses about how volunteers learned about the study (n = 896) and demographic data from eligible participants who came for an initial study visit (n = 216) to determine the strengths and weaknesses of recruitment strategies. Social media-based strategies resulted in the highest number of individuals screened (n = 444, 26% eligible). Dating sites/apps reached large numbers of eligible participants. White-Hispanics and African-Americans were more likely to be recruited through personal contacts; community events successfully reached Hispanic volunteers. Incorporating recruitment queries into pre-screening forms can help modify recruitment strategies for greater efficacy and efficiency. Findings suggest that recruitment strategies need to be tailored to reach specific target populations.