Functional cure of HIV: the scale of the challenge

BRD4 modulator ZL0580 and LEDGINs additively block and lock HIV-1 transcription

The persistence of HIV-1 in a latent state within long-lived immune cells remains a major barrier to a cure for HIV-1 infection. The "block-and-lock" strategy aims to silence the HIV-1 provirus permanently using latency promoting agents (LPAs). LEDGINs, a well-known class of LPAs, inhibit the interaction between viral integrase and LEDGF/p75, reducing viral integration and retargeting the provirus to regions resistant to reactivation. However, proximity to enhancers may still permit residual transcription. Given BRD4's central role in the enhancer biology, we now test two BRD4 modulators, JQ1 and ZL0580. Mechanistic studies reveal that JQ1 and ZL0580 have contrasting effects on Tat-dependent HIV-1 transcription, resulting in JQ1 promoting viral reactivation and ZL0580 inducing transcriptional silencing. Combining ZL0580 with LEDGINs has an additive effect in blocking HIV-1 transcription and reactivation, in both cell lines and primary cells. These findings demonstrate the potential of ZL0580 to enhance the block-and-lock cure strategy.

CAR-NK cell therapy: a potential antiviral platform

Viral infections persist as a significant cause of morbidity and mortality worldwide. Conventional therapeutic approaches often fall short in fully eliminating viral infections, primarily due to the emergence of drug resistance. Natural killer (NK) cells, one of the important members of the innate immune system, possess potent immunosurveillance and cytotoxic functions, thereby playing a crucial role in the host's defense against viral infections. Chimeric antigen receptor (CAR)-NK cell therapy has been developed to redirect the cytotoxic function of NK cells specifically towards virus-infected cells, further enhancing their cytotoxic efficacy. In this manuscript, we review the role of NK cells in antiviral infections and explore the mechanisms by which viruses evade immune detection. Subsequently, we focus on the optimization strategies for CAR-NK cell therapy to address existing limitations. Furthermore, we discuss significant advancements in CAR-NK cell therapy targeting viral infections, including those caused by severe acute respiratory syndrome coronavirus 2, human immunodeficiency virus, hepatitis B virus, human cytomegalovirus, and Epstein-Barr virus.

Mechanism for evolution of diverse autologous antibodies upon broadly neutralizing antibody therapy of people with HIV

Antiretroviral therapy (ART) inhibits Human Immunodeficiency Virus (HIV) replication to maintain undetectable viral loads in people living with HIV, but does not result in a cure. Due to the significant challenges of lifelong ART for many, there is strong interest in therapeutic strategies that result in cure. Recent clinical trials have shown that administration of broadly neutralizing antibodies (bnAbs) when there is some viremia can lead to ART-free viral control in some people; however, the underlying mechanisms are unclear. Our computational modeling shows that bnAbs administered in the presence of some viremia promote the evolution of autologous antibodies (aAbs) that target diverse epitopes of HIV spike proteins. This "net" of polyclonal aAbs could confer control since evasion of this response would require developing mutations in multiple epitopes. Our results provide a common mechanistic framework underlying recent clinical observations upon bnAb/ART therapy, and they should also motivate and inform new trials.

Tracking HIV persistence across T cell lineages during early ART-treated HIV-1-infection using a reservoir-marking humanized mouse model

Human immunodeficiency virus (HIV) infection depletes CD4 T-cells, and long-term persistence of latent virus prevents full clearance of HIV even in the presence of effective antiretroviral therapy (ART), Here we present the HIV-1-induced lineage tracing (HILT) system, a model that irreversibly marks infected cells within a humanized mouse model, which detects rare latently infected cells. Immunodeficient mice transplanted with genetically modified hematopoietic stem cells develop a human immune system, in which CD4 T-cells contain a genetic switch that permanently labels cells infected by HIV-1 expressing cre-recombinase. Through single-cell RNA sequencing of HILT-marked cells during acute infection and post-ART treatment, we identify distinct CD4+ T-cell transcriptional lineages enriched in either active or latent infections. Comparative gene expression analysis highlights common pathways modulated in both states, including EIF2, Sirtuin, and protein ubiquitination. Critical regulators of these pathways, including JUN, BCL2, and MDM2, change to opposite directions in the two states, highlighting gene expression programs that may support HIV persistence across T-cell lineages and states.

HIV controllers: hope for a functional cure

Elite controllers (ECs) and post-treatment controllers (PTCs) represent important models for achieving a functional cure for HIV. This review synthesizes findings from immunological, genetic, and virological studies to compare the mechanisms underlying HIV suppression in ECs and PTCs. Although ECs maintain viral control without antiretroviral therapy (ART), PTCs achieve suppression following ART discontinuation. Both groups rely on adaptive and innate immunity, host genetic factors, and characteristics of the HIV reservoir; however, they exhibit distinct immune responses and genetic profiles. These differences provide insights into strategies for sustained ART-free remission. Understanding the shared and unique mechanisms in ECs and PTCs can inform the development of novel therapeutic approaches, including immune-based therapies and genome editing, to achieve a functional cure for HIV-1.

PET imaging of HIV-1 envelope protein gp120 using 18F-labeled nanobodies

Radiolabeled antibodies against the HIV-1 envelope protein, gp120, have been previously tested in animal models and in people with HIV (PWH). Nanobodies offer advantages over antibodies, including smaller size and faster clearance, which allow labeling with fluorine-18. In this study, three nanobodies (J3, 3E3, B9) chosen based on their binding properties to the conserved CD4-binding site of gp120 were labeled with fluorine-18 and used for PET imaging in mice bearing wild-type (WT) and/or gp120-expressing (Env+) tumors. [18F]J3 and [18F]3E3 selectively targeted Env+ tumors and not WT tumors, with minimal background signal. Switching from non-site-specific radiolabeling method to sortase A-mediated site-specific conjugation at the C-terminus improved binding to Env+ tumors for all nanobodies. Site-specifically 18F-labeled J3 nanobody is the most promising candidate with the highest level of binding. These results establish an Env+ imaging method that will enable next stage testing in an HIV-1 preclinical infection model and potentially in PWH.

Interrelationship between altered metabolites and the gut microbiota in people living with HIV with different immune responses to antiretroviral therapy

Background

Antiretroviral therapy (ART) effectively reduces opportunistic infections and mortality in people living with HIV (PLWH); however, some patients exhibit poor immune recovery. This study explores the connections among immune responses, metabolites, and the gut microbiota in PLWH with differing reactions to ART.

Methods

We analyzed the gut microbiota composition, metabolites, and immune markers in 38 PLWH who showed an immunological response (IR) and 32 who did not (INR), as classified according to CD4+ T-cell levels after 24 months of ART. Additionally, in vitro assays using cell counting kit 8, flow cytometry, and quantitative real-time reverse transcription PCR were employed to assess the effects of the metabolites on cell viability, immune marker expression, and cytokine levels.

Results

Gut microbiota and metabolic profiles differed significantly between the IR and INR groups. Enterococcus was more abundant in the INR group, whereas [Ruminococcus]_gnavus_group levels were reduced. Significant metabolic pathway alterations included decreased folate biosynthesis and biotin metabolism. We observed negative associations of Parabacteroides with activation markers on CD4+ T-cells, and positive correlations with CD4/CD8 ratios. Enterococcus showed inverse relationships with these markers. Indole-3-acetyl-beta-1-D-glucoside (area under the curve value = 0.8931), had the best discriminatory ability. Further experiments showed that Indole-3-acetyl-beta-1-D-glucoside significantly decreased the proportions of CD4+CD57+, effector CD4+, CD4+PD1+, CD8+CD57+, effector CD8+, and CD8+HLA-DR+ T cells. Moreover, mRNA expression analysis showed that Indole-3-acetyl-beta-1-D-glucoside treatment led to a suppression of pro-inflammatory cytokines.

Conclusion

The multi-omics approach highlighted potential biomarkers for immune recovery in HIV, suggesting avenues for further research into treatment strategies.

High frequency CCR5 editing in human hematopoietic stem progenitor cells protects xenograft mice from HIV infection

The only cure of HIV has been achieved in a small number of people who received a hematopoietic stem cell transplant (HSCT) comprising allogeneic cells carrying a rare, naturally occurring, homozygous deletion in the CCR5 gene. The rarity of the mutation and the significant morbidity and mortality of such allogeneic transplants precludes widespread adoption of this HIV cure. Here, we show the application of CRISPR/Cas9 to achieve >90% CCR5 editing in human, mobilized hematopoietic stem progenitor cells (HSPC), resulting in a transplant that undergoes normal hematopoiesis, produces CCR5 null T cells, and renders xenograft mice refractory to HIV infection. Titration studies transplanting decreasing frequencies of CCR5 edited HSPCs demonstrate that <90% CCR5 editing confers decreasing protective benefit that becomes negligible between 54% and 26%. Our study demonstrates the feasibility of using CRISPR/Cas9/RNP to produce an HSPC transplant with high frequency CCR5 editing that is refractory to HIV replication. These results raise the potential of using CRISPR/Cas9 to produce a curative autologous HSCT and bring us closer to the development of a cure for HIV infection.

"Pseudosubstrate Envelope"/Free Energy Perturbation-Guided Design and Mechanistic Investigations of Benzothiazole HIV Capsid Modulators with High Ligand Efficiency

Based on our proposed "pseudosubstrate envelope" concept, 25 benzothiazole-bearing HIV capsid protein (CA) modulators were designed and synthesized under the guidance of free energy perturbation technology. The most potent compound, IC-1k, exhibited an EC50 of 2.69 nM against HIV-1, being 393 times more potent than the positive control PF74. Notably, IC-1k emerged as the highest ligand efficiency (LE = 0.32) HIV CA modulator, surpassing that of the approved drug lenacapavir (LE = 0.21). Surface plasmon resonance assay and crystallographic analysis confirmed that IC-1k targeted HIV-1 CA within the chemical space of the "pseudosubstrate envelope". Further mechanistic studies revealed a dual-stage inhibition profile: IC-1k disrupted early-stage capsid-host-factor interactions and promoted late-stage capsid misassembly. Preliminary pharmacokinetic evaluations demonstrated significantly improved metabolic stability in human liver microsomes for IC-1k (T1/2 = 91.3 min) compared to PF74 (T1/2 = 0.7 min), alongside a favorable safety profile. Overall, IC-1k presents a promising lead compound for further optimization.

Anti-PD-L1 antibody ASC22 in combination with a histone deacetylase inhibitor chidamide as a "shock and kill" strategy for ART-free virological control: a phase II single-arm study

The combination of ASC22, an anti-PD-L1 antibody potentially enhancing HIV-specific immunity and chidamide, a HIV latency reversal agent, may serve as a strategy for antiretroviral therapy-free virological control for HIV. People living with HIV, having achieved virological suppression, were enrolled to receive ASC22 and chidamide treatment in addition to their antiretroviral therapy. Participants were monitored over 24 weeks to measure changes in viral dynamics and the function of HIV-specific CD8+ T cells (NCT05129189). 15 participants completed the study. At week 8, CA HIV RNA levels showed a significant increase from baseline, and the values returned to baseline after discontinuing ASC22 and chidamide. The total HIV DNA was only transiently increased at week 4 (P = 0.014). In contrast, integrated HIV DNA did not significantly differ from baseline. Increases in the proportions of effector memory CD4+ and CD8+ T cells (TEM) were observed from baseline to week 24 (P = 0.034 and P = 0.002, respectively). The combination treatment did not succeed in enhancing the function of HIV Gag/Pol- specific CD8+ T cells. Nevertheless, at week 8, a negative correlation was identified between the proportions of HIV Gag-specific TEM cells and alterations in integrated DNA in the T cell function improved group (P = 0.042 and P = 0.034, respectively). Nine adverse events were solicited, all of which were graded 1 and resolved spontaneously. The combined treatment of ASC22 and chidamide was demonstrated to be well-tolerated and effective in activating latent HIV reservoirs. Further investigations are warranted in the context of analytic treatment interruption.

Gaining momentum: stem cell therapies for HIV cure

PURPOSE OF REVIEW

Durable HIV-1 remission has been reported in a person who received allogeneic stem cell transplants (SCTs) involving CCR5 Δ32/Δ32 donor cells. Much of the reduction in HIV-1 burden following allogeneic SCT with or without donor cells inherently resistant to HIV-1 infection is likely due to cytotoxic graft-versus-host effects on residual recipient immune cells. Nonetheless, there has been growing momentum to develop and implement stem cell therapies that lead to durable long-term antiretroviral therapy (ART)-free remission without the need for SCT.

RECENT FINDINGS

Most current research leverages gene editing techniques to modify hematopoietic stem cells which differentiate into immune cells capable of harboring HIV-1. Approaches include targeting genes that encode HIV-1 co-receptors using Zinc Finger Nucleases (ZFN) or CRISPR-Cas-9 to render a pool of adult or progenitor cells resistant to de-novo infection. Other strategies involve harnessing multipotent mesenchymal stromal cells to foster immune environments that can more efficiently recognize and target HIV-1 while promoting tissue homeostasis.

SUMMARY

Many of these strategies are currently in a state of infancy or adolescence; nonetheless, promising preclinical and first-in-human studies have been performed, providing further rationale to focus resources on stem cell therapies.

CRISPR/CAS as a Powerful Tool for Human Immunodeficiency Virus Cure: A Review

Despite care and the availability of effective antiretroviral treatment, some human immunodeficiency virus (HIV)-infected individuals suffer from neurocognitive disorders associated with HIV (HAND) that significantly affect their quality of life. The different types of HAND can be divided into asymptomatic neurocognitive impairment, mild neurocognitive disorder, and the most severe form known as HIV-associated dementia. Little is known about the mechanisms of HAND, but it is thought to be related to infection of astrocytes, microglial cells, and macrophages in the human brain. The formation of a viral reservoir that lies dormant as a provirus in resting CD4+ T lymphocytes and in refuge tissues such as the brain contributes significantly to HIV eradication. In recent years, a new set of tools have emerged: the gene editing based on the clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 system, which can alter genome segments by insertion, deletion, and replacement and has great therapeutic potential. This technology has been used in research to treat HIV and appears to offer hope for a possible cure for HIV infection and perhaps prevention of HAND. This approach has the potential to directly impact the quality of life of HIV-infected individuals, which is a very important topic to be known and discussed.

Reshaping the narrative: Tracing the historical trajectory of HIV/AIDS, gay men, and public health in Sweden

The human immunodeficiency virus (HIV) emerged as an endemic health crisis in the United States during the early 1980s. Initially labelled a "gay disease" due to its prevalence among gay men, the spread of HIV led to widespread fear and moral panic, as there was limited medical knowledge on preventing its transmission. While HIV is often associated with Sub-Saharan Africa, this article focuses on Sweden, a pioneering nation that became the first to achieve the remarkable Joint UNAIDS/WHO 90-90-90 continuum in addressing the epidemic. However, despite this significant milestone, the punitive legislation and attitudes prevalent in Sweden have had a counterproductive effect on curbing the virus's spread. Drawing upon a comprehensive triangulation of various data and sources on the evolution of public policy in Sweden, this article argues for the urgent need to reduce stigma surrounding HIV and AIDS. By undertaking further measures to combat stigmatisation, we not only have the potential to prevent the spread of HIV but also significantly enhance the quality of life for individuals living with the virus. An essential step in this journey is to eliminate the legally-enforced mandatory disclosure of one's HIV status, which would mark a tremendous victory for all those affected. With limited evidence to support the effectiveness of criminalisation and penal laws, no longer being viewed as criminals for non-disclosure would be a monumental achievement, positively transforming the lives of people living with HIV and fostering a more inclusive and supportive society.

Cocaine regulates antiretroviral therapy CNS access through pregnane-x receptor-mediated drug transporter and metabolizing enzyme modulation at the blood brain barrier

BACKGROUND

Appropriate interactions between antiretroviral therapies (ART) and drug transporters and metabolizing enzymes at the blood brain barrier (BBB) are critical to ensure adequate dosing of the brain to achieve HIV suppression. These proteins are modulated by demographic and lifestyle factors, including substance use. While understudied, illicit substances share drug transport and metabolism pathways with ART, increasing the potential for adverse drug:drug interactions. This is particularly important when considering the brain as it is relatively undertreated compared to peripheral organs and is vulnerable to substance use-mediated damage.

METHODS

We used an in vitro model of the human BBB to determine the extravasation of three first-line ART drugs, emtricitabine (FTC), tenofovir (TFV), and dolutegravir (DTG), in the presence and absence of cocaine, which served as our illicit substance model. The impact of cocaine on BBB integrity and permeability, drug transporters, metabolizing enzymes, and their master transcriptional regulators were evaluated to determine the mechanisms by which substance use impacted ART central nervous system (CNS) availability.

RESULTS

We determined that cocaine had a selective impact on ART extravasation, where it increased FTC's ability to cross the BBB while decreasing TFV. DTG concentrations that passed the BBB were below quantifiable limits. Interestingly, the potent neuroinflammatory modulator, lipopolysaccharide, had no effect on ART transport, suggesting a specificity for cocaine. Unexpectedly, cocaine did not breach the BBB, as permeability to albumin and 4 kDa FITC-dextran, as well as tight junction proteins and adhesion molecules remained unchanged. Rather, cocaine selectively decreased the pregnane-x receptor (PXR), but not constitutive androstane receptor (CAR). Consequently, drug transporter expression and activity decreased in endothelial cells of the BBB, including p-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 4 (MRP4). Further, cytochrome P450 3A4 (CYP3A4) enzymatic activity increased following cocaine treatment that coincided with decreased expression. Finally, cocaine modulated adenylate kinases that are required to facilitate biotransformation of ART prodrugs to their phosphorylated, pharmacologically active counterparts.

CONCLUSION

Our findings indicate that additional considerations are needed in CNS HIV treatment strategies for people who use cocaine, as it may limit ART efficacy through regulation of drug transport and metabolizing pathways at the BBB.

Discovery, Crystallographic Studies, and Mechanistic Investigations of Novel Phenylalanine Derivatives Bearing a Quinazolin-4-one Scaffold as Potent HIV Capsid Modulators

Optimization of compound 11L led to the identification of novel HIV capsid modulators, quinazolin-4-one-bearing phenylalanine derivatives, displaying potent antiviral activities against both HIV-1 and HIV-2. Notably, derivatives 12a2 and 21a2 showed significant improvements, with 2.5-fold over 11L and 7.3-fold over PF74 for HIV-1, and approximately 40-fold over PF74 for HIV-2. The X-ray co-crystal structures confirmed the multiple pocket occupation of 12a2 and 21a2 in the binding site. Mechanistic studies revealed a dual-stage inhibition profile, where the compounds disrupted capsid-host factor interactions at the early stage and promoted capsid misassembly at the late stage. Remarkably, 12a2 and 21a2 significantly promoted capsid misassembly, outperforming 11L, PF74, and LEN. The substitution of easily metabolized amide bond with quinolin-4-one marginally enhanced the stability of 12a2 in human liver microsomes compared to controls. Overall, 12a2 and 21a2 highlight their potential as potent HIV capsid modulators, paving the way for future advancements in anti-HIV drug design.

A follow-up study: 6-year cART-free virologic control of rhesus macaques after PD-1-based DNA vaccination against pathogenic SHIVSF162P3CN challenge

IMPORTANCE

Efficient strategies for HIV-1 cART-free virologic control are critical for ending the AIDS pandemic. The essential role of effector-memory CD8+ T cells in controlling viremia and eliminating virus-infected cells has made them a promising target for vaccine development. It has been previously reported that PD-1-based DNA vaccination was effective in inducing polyfunctional effector-memory CD8+ T cells for AIDS virus control for 2 years in rhesus monkeys. This follow-up study extends the findings and shows that a viremia-free period of over 6 years was detected in two monkeys immunized with PD-1-based DNA vaccine against pathogenic SHIVSF162P3CN infection in the absence of antiretroviral therapy. Long-term vaccine-induced memory T cell responses were detected. Our results warrant the clinical trials of PD-1-based DNA vaccines for achieving HIV-1 cART-free virologic control used either alone or in combination with other biomedical interventions.

Label-free detection of synthetic, full genomic length HIV-1 RNA at the few-copy level

Oligonucleotide-functionalized graphene biosensors show immense promise for use as label-free point of care devices for detection of nucleic acid biomarkers at clinically relevant levels. Graphene-based nucleic acid sensors can be fabricated at low cost and have been shown to reach limits of detection in the attomolar range. Here we demonstrate devices functionalized with 22mer or 8omer DNA probes are capable of detecting full length genomic HIV-1 subtype B RNA, with a limit of detection below 1 aM in nuclease free water. We also show that these sensors are suitable for detection directly in Qiazol lysis reagent, again with a limit of detection below 1 aM for both 22mer and 8omer probes.

Cocaine Regulates Antiretroviral Therapy CNS Access Through Pregnane-X Receptor-Mediated Drug Transporter and Metabolizing Enzyme Modulation at the Blood Brain Barrier

Background

Appropriate interactions between antiretroviral therapies (ART) and drug transporters and metabolizing enzymes at the blood brain barrier (BBB) are critical to ensure adequate dosing of the brain to achieve HIV suppression. These proteins are modulated by demographic and lifestyle factors, including substance use. While understudied, illicit substances share drug transport and metabolism pathways with ART, increasing the potential for adverse drug:drug interactions. This is particularly important when considering the brain as it is relatively undertreated compared to peripheral organs and is vulnerable to substance use-mediated damage.

Methods

We used an in vitro model of the human BBB to determine the extravasation of three first-line ART drugs, emtricitabine (FTC), tenofovir (TFV), and dolutegravir (DTG), in the presence and absence of cocaine, which served as our illicit substance model. The impact of cocaine on BBB integrity and permeability, drug transporters, metabolizing enzymes, and their master transcriptional regulators were evaluated to determine the mechanisms by which substance use impacted ART central nervous system (CNS) availability.

Results

We determined that cocaine had a selective impact on ART extravasation, where it increased FTC's ability to cross the BBB while decreasing TFV. DTG concentrations that passed the BBB were below quantifiable limits. Interestingly, the potent neuroinflammatory modulator, lipopolysaccharide, had no effect on ART transport, suggesting a specificity for cocaine. Unexpectedly, cocaine did not breach the BBB, as permeability to albumin and tight junction proteins and adhesion molecules remained unchanged. Rather, cocaine selectively decreased the pregnane-x receptor (PXR), but not constitutive androstane receptor (CAR). Consequently, drug transporter expression and activity decreased in endothelial cells of the BBB, including p-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 4 (MRP4). Further, cytochrome P450 3A4 (CYP3A4) enzymatic activity increased following cocaine treatment that coincided with decreased expression. Finally, cocaine modulated adenylate kinases are required to facilitate biotransformation of ART prodrugs to their phosphorylated, pharmacologically active counterparts.

Conclusion

Our findings indicate that additional considerations are needed in CNS HIV treatment strategies for people who use cocaine, as it may limit ART efficacy through regulation of drug transport and metabolizing pathways at the BBB.

Potential biomarkers: Predicting post-treatment viral rebound in rhesus macaques

In this issue of Cell Reports Medicine, Aid and colleagues define peripheral blood biomarkers, which predict viral rebound after antiretroviral therapy (ART) discontinuation in SIV-infected rhesus macaques treated early with ART, providing insights into potential HIV cure strategies.¹.

Impact of misclassified defective proviruses on HIV reservoir measurements

Most proviruses persisting in people living with HIV (PWH) on antiretroviral therapy (ART) are defective. However, rarer intact proviruses almost always reinitiate viral rebound if ART stops. Therefore, assessing therapies to prevent viral rebound hinges on specifically quantifying intact proviruses. We evaluated the same samples from 10 male PWH on ART using the two-probe intact proviral DNA assay (IPDA) and near full length (nfl) Q4PCR. Both assays admitted similar ratios of intact to total HIV DNA, but IPDA found ~40-fold more intact proviruses. Neither assay suggested defective proviruses decay over 10 years. However, the mean intact half-lives were different: 108 months for IPDA and 65 months for Q4PCR. To reconcile this difference, we modeled additional longitudinal IPDA data and showed that decelerating intact decay could arise from very long-lived intact proviruses and/or misclassified defective proviruses: slowly decaying defective proviruses that are intact in IPDA probe locations (estimated up to 5%, in agreement with sequence library based predictions). The model also demonstrates how misclassification can lead to underestimated efficacy of therapies that exclusively reduce intact proviruses. We conclude that sensitive multi-probe assays combined with specific nfl-verified assays would be optimal to document absolute and changing levels of intact HIV proviruses.

Persistent hepatitis B virus and HIV coinfections in dually humanized mice engrafted with human liver and immune system

Chronic hepatitis B (CHB), caused by hepatitis B virus (HBV), remains a major medical problem. HBV has a high propensity for progressing to chronicity and can result in severe liver disease, including fibrosis, cirrhosis, and hepatocellular carcinoma. CHB patients frequently present with viral coinfection, including human immunodeficiency virus type (HIV) and hepatitis delta virus. About 10% of chronic HIV carriers are also persistently infected with HBV, which can result in more exacerbated liver disease. Mechanistic studies of HBV-induced immune responses and pathogenesis, which could be significantly influenced by HIV infection, have been hampered by the scarcity of immunocompetent animal models. Here, we demonstrate that humanized mice dually engrafted with components of a human immune system and a human liver supported HBV infection, which was partially controlled by human immune cells, as evidenced by lower levels of serum viremia and HBV replication intermediates in the liver. HBV infection resulted in priming and expansion of human HLA-restricted CD8+ T cells, which acquired an activated phenotype. Notably, our dually humanized mice support persistent coinfections with HBV and HIV, which opens opportunities for analyzing immune dysregulation during HBV and HIV coinfection, and preclinical testing of novel immunotherapeutics.

Identification of aryl hydrocarbon receptor as a barrier to HIV-1 infection and outgrowth in CD4+ T cells

The aryl hydrocarbon receptor (AhR) regulates Th17-polarized CD4+ T cell functions, but its role in HIV-1 replication/outgrowth remains unknown. Genetic (CRISPR-Cas9) and pharmacological inhibition reveal AhR as a barrier to HIV-1 replication in T cell receptor (TCR)-activated CD4+ T cells in vitro. In single-round vesicular stomatitis virus (VSV)-G-pseudotyped HIV-1 infection, AhR blockade increases the efficacy of early/late reverse transcription and subsequently facilitated integration/translation. Moreover, AhR blockade boosts viral outgrowth in CD4+ T cells of people living with HIV-1 (PLWH) receiving antiretroviral therapy (ART). Finally, RNA sequencing reveals genes/pathways downregulated by AhR blockade in CD4+ T cells of ART-treated PLWH, including HIV-1 interactors and gut-homing molecules with AhR-responsive elements in their promoters. Among them, HIC1, a repressor of Tat-mediated HIV-1 transcription and a tissue-residency master regulator, is identified by chromatin immunoprecipitation as a direct AhR target. Thus, AhR governs a T cell transcriptional program controlling viral replication/outgrowth and tissue residency/recirculation, supporting the use of AhR inhibitors in "shock and kill" HIV-1 remission/cure strategies.

Gene dysregulation in acute HIV-1 infection – early transcriptomic analysis reveals the crucial biological functions affected

Introduction

Transcriptomic analyses from early human immunodeficiency virus (HIV) infection have the potential to reveal how HIV causes widespread and lasting damage to biological functions, especially in the immune system. Previous studies have been limited by difficulties in obtaining early specimens.

Methods

A hospital symptom-based screening approach was applied in a rural Mozambican setting to enrol patients with suspected acute HIV infection (Fiebig stage I-IV). Blood samples were collected from all those recruited, so that acute cases and contemporaneously recruited, uninfected controls were included. PBMC were isolated and sequenced using RNA-seq. Sample cellular composition was estimated from gene expression data. Differential gene expression analysis was completed, and correlations were determined between viral load and differential gene expression. Biological implications were examined using Cytoscape, gene set enrichment analysis, and enrichment mapping.

Results

Twenty-nine HIV infected subjects one month from presentation and 46 uninfected controls were included in this study. Subjects with acute HIV infection demonstrated profound gene dysregulation, with 6131 (almost 13% of the genome mapped in this study) significantly differentially expressed. Viral load was correlated with 1.6% of dysregulated genes, in particular, highly upregulated genes involved in key cell cycle functions, were correlated with viremia. The most profoundly upregulated biological functions related to cell cycle regulation, in particular, CDCA7 may drive aberrant cell division, promoted by overexpressed E2F family proteins. Also upregulated were DNA repair and replication, microtubule and spindle organization, and immune activation and response. The interferome of acute HIV was characterized by broad activation of interferon-stimulated genes with antiviral functions, most notably IFI27 and OTOF. BCL2 downregulation alongside upregulation of several apoptotic trigger genes and downstream effectors may contribute to cycle arrest and apoptosis. Transmembrane protein 155 (TMEM155) was consistently highly overexpressed during acute infection, with roles hitherto unknown.

Discussion

Our study contributes to a better understanding of the mechanisms of early HIV-induced immune damage. These findings have the potential to lead to new earlier interventions that improve outcomes.

The Combination of an mRNA Immunogen, a TLR7 Agonist and a PD1 Blocking Agent Enhances In-Vitro HIV T-Cell Immune Responses

The development of new strategies to achieve a functional cure for HIV remains a priority. We tested a novel HIV therapeutic vaccine using unmodified mRNA (TMEP-B) and mRNA modified by 1-methyl-3'-pseudouridylyl (TMEP-Bmod) expressing both a multiepitopic sequences from Gag, Pol, and Nef proteins, including different CD4 and CD8 T-cell epitopes functionally associated with HIV control in transfected monocyte-derived dendritic cells (MDDCs) obtained from HIV infected patients. In vitro assays were used to test the mRNAs alone and in combination with immunomodulator agents, such as the TLR-7 agonist Vesatolimod and the PD-1 antagonist Nivolumab to try to improve HIV-specific cellular immune responses. Combining the mRNAs with the immunomodulators enhanced HIV-specific T-cell responses, together with the secretion of IFNγ, IP10, MIP-1α, and MIP-1β, which are fundamental mediators of viral control. Our data suggest that the mRNA vaccine prototypes TMEP-B and TMEP-Bmod, when combined with Vesatolimod and/or Nivolumab, could achieve functional cure for patients with HIV.

Determinants of Retroviral Integration and Implications for Gene Therapeutic MLV-Based Vectors and for a Cure for HIV-1 Infection

To complete their replication cycle, retroviruses need to integrate a DNA copy of their RNA genome into a host chromosome. Integration site selection is not random and is driven by multiple viral and cellular host factors specific to different classes of retroviruses. Today, overwhelming evidence from cell culture, animal experiments and clinical data suggests that integration sites are important for retroviral replication, oncogenesis and/or latency. In this review, we will summarize the increasing knowledge of the mechanisms underlying the integration site selection of the gammaretrovirus MLV and the lentivirus HIV-1. We will discuss how host factors of the integration site selection of retroviruses may steer the development of safer viral vectors for gene therapy. Next, we will discuss how altering the integration site preference of HIV-1 using small molecules could lead to a cure for HIV-1 infection.

Health horizons: Future trends and technologies from the European Medicines Agency's horizon scanning collaborations

In medicines development, the progress in science and technology is accelerating. Awareness of these developments and their associated challenges and opportunities is essential for medicines regulators and others to translate them into benefits for society. In this context, the European Medicines Agency uses horizon scanning to shine a light on early signals of relevant innovation and technological trends with impact on medicinal products. This article provides the results of systematic horizon scanning exercises conducted by the Agency, in collaboration with the World Health Organization (WHO) and the European Commission's Joint Research Centre's (DG JRC). These collaborative exercises aim to inform policy-makers of new trends and increase preparedness in responding to them. A subset of 25 technological trends, divided into three clusters were selected and reviewed from the perspective of medicines regulators. For each of these trends, the expected impact and challenges for their adoption are discussed, along with recommendations for developers, regulators and policy makers.

Impact of antiretroviral therapy in primary HIV infection on natural killer cell function and the association with viral rebound and HIV DNA following treatment interruption

Natural Killer (NK) cells play a key role in controlling HIV replication, with potential downstream impact on the size of the HIV reservoir and likelihood of viral rebound after antiretroviral therapy (ART) cessation. It is therefore important to understand how primary HIV infection (PHI) disrupts NK cell function, and how these functions are restored by early ART. We examined the impact of commencing ART during PHI on phenotypic and functional NK cell markers at treatment initiation (baseline), 3 months, 1 year, and 2 years in seven well-characterised participants in comparison to HIV seronegative volunteers. We then examined how those NK cell properties differentially impacted by ART related to time to viral rebound and HIV DNA levels in 44 individuals from the SPARTAC trial who stopped ART after 48 weeks treatment, started during PHI. NK cell markers that were significantly different between the seven people with HIV (PWH) treated for 2 years and HIV uninfected individuals included NKG2C levels in CD56dim NK cells, Tim-3 expression in CD56bright NK cells, IFN-γ expressed by CD56dim NK cells after IL-12/IL-18 stimulation and the fraction of Eomes-/T-bet+ in CD56dim and CD56bright NK cells. When exploring time to viral rebound after stopping ART among the 44 SPARTAC participants, no single NK phenotypic marker correlated with control. Higher levels of IL-12/IL-18 mediated NK cell degranulation at baseline were associated with longer times to viral rebound after treatment interruption (P=0.028). Additionally, we found higher fractions of CD56dim NK cells in individuals with lower levels of HIV DNA (P=0.048). NKG2A and NKp30 levels in CD56neg NK cells were higher in patients with lower HIV DNA levels (p=0.00174, r=-0.49 and p=0.03, r= -0.327, respectively) while CD27 levels were higher in those with higher levels of HIV DNA (p=0.026). These data show NK cell functions are heterogeneously impacted by HIV infection with a mixed picture of resolution on ART, and that while NK cells may affect HIV DNA levels and time to viral rebound, no single NK cell marker defined delayed viral rebound.

Metabolite Identification of HIV-1 Capsid Modulators PF74 and 11L in Human Liver Microsomes

PF74 and 11L, as potent modulators of the HIV-1 capsid protein, have been demonstrated to act at both early and late stages in the HIV-1 life cycle. However, their clearance is high in human liver microsomes (HLMs). The main goal of this study was to clarify the metabolism of PF74 and 11L in HLMs, and provide guidance for future structural optimization. To accomplish this, the phase-I metabolites of PF74 and 11L, resulting from in vitro incubation with HLMs, were investigated via ultra-performance liquid chromatography–ultraviolet–high-resolution mass spectrometry (UPLC–UV–HRMS). The results show that 17 phase-I metabolites were putatively annotated for PF74, whereas 16 phase-I metabolites were found for 11L. The main metabolic pathways of PF74 in HLMs were oxidation and demethylation, and the secondary metabolic pathway was hydrolysis; thus, the di-oxidation and demethylation products (M7, M9, M11, and M14) were found to be major metabolites of PF74 in HLMs. In comparison, the main metabolic pathways of 11L in HLMs were oxidation, demethylation, dehydrogenation, and oxidative deamination, with M6′, M11′, M15′, and M16′ as the main metabolites. We suggest that the indole ring and N-methyl group of PF74, and the aniline group, benzene ring R1′, N-methyl, and methoxy group of 11L, were the main metabolic soft spots. Therefore, our research illuminates structural optimization options in seeking improved HIV-1 CA modulators.

CBX4 contributes to HIV-1 latency by forming phase-separated nuclear bodies and SUMOylating EZH2

The retrovirus HIV-1 integrates into the host genome and establishes a latent viral reservoir that escapes immune surveillance. Molecular mechanisms of HIV-1 latency have been studied extensively to achieve a cure for the acquired immunodeficiency syndrome (AIDS). Latency-reversing agents (LRAs) have been developed to reactivate and eliminate the latent reservoir by the immune system. To develop more promising LRAs, it is essential to evaluate new therapeutic targets. Here, we find that CBX4, a component of the Polycomb Repressive Complex 1 (PRC1), contributes to HIV-1 latency in seven latency models and primary CD4+ T cells. CBX4 forms nuclear bodies with liquid-liquid phase separation (LLPS) properties on the HIV-1 long terminal repeat (LTR) and recruits EZH2, the catalytic subunit of PRC2. CBX4 SUMOylates EZH2 utilizing its SUMO E3 ligase activity, thereby enhancing the H3K27 methyltransferase activity of EZH2. Our results indicate that CBX4 acts as a bridge between the repressor complexes PRC1 and PRC2 that act synergistically to maintain HIV-1 latency. Dissolution of phase-separated CBX4 bodies could be a potential intervention to reactivate latent HIV-1.

Recent Advances in the Discovery and Development of Anti-HIV Natural Products

Acquired immunodeficiency syndrome (AIDS) caused by human immunodeficiency virus (HIV) infection is a serious public problem threatening global health. At present, although "cocktail therapy" has achieved significant clinical effects, HIV still cannot be completely eradicated. Furthermore, long-term antiviral treatment has caused problems such as toxic side effects, the emergence of drug-resistant viruses, and poor patient compliance. Therefore, it is highly necessary to continue to search for high-efficient, low-toxic anti-HIV drugs with new mechanisms. Natural products have the merits of diverse scaffolds, biological activities, and low toxicity that are deemed the important sources of drug discovery. Thus, finding lead compounds from natural products followed by structure optimization has become one of the important ways of modern drug discovery. Nowadays, many natural products have been found, such as berberine, gnidimacrin, betulone, and kuwanon-L, which exert effective anti-HIV activity through immune regulation, inhibition of related functional enzymes in HIV replication, and anti-oxidation. This paper reviewed these natural products, their related chemical structure optimization, and their anti-HIV mechanisms.

Insights into the HIV-1 Latent Reservoir and Strategies to Cure HIV-1 Infection

Since the first discovery of human immunodeficiency virus 1 (HIV-1) in 1983, the targeted treatment, antiretroviral therapy (ART), has effectively limited the detected plasma viremia below a very low level and the technique has been improved rapidly. However, due to the persistence of the latent reservoir of replication-competent HIV-1 in patients treated with ART, a sudden withdrawal of the drug inevitably results in HIV viral rebound and HIV progression. Therefore, more understanding of the HIV-1 latent reservoir (LR) is the priority before developing a cure that thoroughly eliminates the reservoir. HIV-1 spreads through both the release of cell-free particles and by cell-to-cell transmission. Mounting evidence indicates that cell-to-cell transmission is more efficient than cell-free transmission of particles and likely influences the pathogenesis of HIV-1 infection. This mode of viral transmission also influences the generation and maintenance of the latent reservoir, which represents the main obstacle for curing the infection. In this review, the definition, establishment, and maintenance of the HIV-1 LR, along with the state-of-the-art quantitative approaches that directly quantify HIV-1 intact proviruses, are elucidated. Strategies to cure HIV infection are highlighted. This review will renew hope for a better and more thorough cure of HIV infection for mankind and encourage more clinical trials to achieve ART-free HIV remission.

Highly dampened HIV-specific cytolytic effector T cell responses define viremic non-progression

This study reports on HIV-specific T cell responses in HIV-1 infected Viremic Non-Progressors (VNPs), a rare group of people living with HIV that exhibit asymptomatic infection over several years accompanied by stable CD4+ T cell counts in spite of ongoing viral replication. We attempted to identify key virus-specific functional attributes that could underlie the apparently paradoxical virus-host equilibrium observed in VNPs. Our results revealed modulation of HIV-specific CD4+ and CD8+ effector T cell responses in VNPs towards a dominant non-cytolytic profile with concomitantly diminished degranulation (CD107a+) ability. Further, the HIV specific CD8+ effector T cell response was primarily enriched for MIP-1β producing cells. As expected, concordant with better viral suppression, VCs exhibit a robust cytolytic T cell response. Interestingly, PuPs shared features common to both these responses but did not exhibit a CD4+ central memory IFN-γ producing Gag-specific response that was shared by both non-progressor (VC and VNP) groups, suggesting CD4 helper response is critical for non-progression. Our study also revealed that cytolytic response in VNPs is primarily limited to polyfunctional cells while both monofunctional and polyfunctional cells significantly contribute to cytolytic responses in VCs. To further understand mechanisms underlying the unique HIV-specific effector T cell response described here in VNPs we also evaluated and demonstrated a possible role for altered gut homing in these individuals. Our findings inform immunotherapeutic interventions to achieve functional cures in the context of ART resistance and serious non AIDS events.

Awareness of HIV functional cure and willingness in participating in related clinical trials: comparison between antiretroviral naïve and experienced men who have sex with men living with HIV

Background

Human immunodeficiency virus (HIV) functional cure is a novel biomedical strategy characterized by sustained viral suppression without the need for life-long medications. The attitude of people living with HIV (PLHIV) towards functional cure and clinical trials are understudied. We aimed to examine the awareness and levels of anticipation for HIV functional cure among men who have sex with men (MSM) living with HIV, and their willingness to join trials as differentiated by their antiretroviral treatment status.

Methods

MSM living with HIV with and those without treatment history were recruited from Hong Kong’s HIV specialist clinics. Self-administered questionnaires covering behavioral profile, perceived impact of HIV cure, attitude towards HIV functional cure and related clinical trials were collected. Clinical data were separately transcribed. Determinants of perceptions and attitudes were identified by logistic regression models.

Results

Of 356 MSM living with HIV recruited, less than half (42%) were aware of HIV functional cure, but they had a high level of anticipation for it. Treatment-experienced participants were more likely to be aware of HIV functional cure. Awareness was associated with continued engagement in sexual activities after HIV diagnosis and sexually transmitted infection (STI) diagnosis. Higher anticipation was observed among older MSM living with HIV but it was negatively associated with one’s awareness. Over 90% were willing to join functional cure trials, especially those who had previously been diagnosed with STI and had engaged in chemsex in the past year. Advice from healthcare professional was an important factor considered by those willing to join clinical trials. Younger, better educated MSM, and those with lower CD4 counts were more concerned about potential risk of AIDS and potential complications upon trial participation.

Conclusions

MSM living with HIV, especially those sexually active, showed positive attitude towards functional cure and willingness to join related clinical trials despite low awareness. To enhance preparedness for HIV functional cure trials, community education, updated information and appropriate medical advice would be needed. Safety is a major concern for potential enrollees in HIV functional cure trials.

Biallelic, Selectable, Knock-in Targeting of CCR5 via CRISPR-Cas9 Mediated Homology Directed Repair Inhibits HIV-1 Replication

Transplanting HIV-1 positive patients with hematopoietic stem cells homozygous for a 32 bp deletion in the chemokine receptor type 5 (CCR5) gene resulted in a loss of detectable HIV-1, suggesting genetically disrupting CCR5 is a promising approach for HIV-1 cure. Targeting the CCR5-locus with CRISPR-Cas9 was shown to decrease the amount of CCR5 expression and HIV-1 susceptibility in vitro as well as in vivo. Still, only the individuals homozygous for the CCR5-Δ32 frameshift mutation confer complete resistance to HIV-1 infection. In this study we introduce a mechanism to target CCR5 and efficiently select for cells with biallelic frameshift insertion, using CRISPR-Cas9 mediated homology directed repair (HDR). We hypothesized that cells harboring two different selectable markers (double positive), each in one allele of the CCR5 locus, would carry a frameshift mutation in both alleles, lack CCR5 expression and resist HIV-1 infection. Inducing double-stranded breaks (DSB) via CRISPR-Cas9 leads to HDR and integration of a donor plasmid. Double-positive cells were selected via fluorescence-activated cell sorting (FACS), and CCR5 was analyzed genetically, phenotypically, and functionally. Targeted and selected populations showed a very high frequency of mutations and a drastic reduction in CCR5 surface expression. Most importantly, double-positive cells displayed potent inhibition to HIV-1 infection. Taken together, we show that targeting cells via CRISPR-Cas9 mediated HDR enables efficient selection of mutant cells that are deficient for CCR5 and highly resistant to HIV-1 infection.

β-catenin regulates HIV latency and modulates HIV reactivation

Latency is the main obstacle towards an HIV cure, with cure strategies aiming to either elicit or prevent viral reactivation. While these strategies have shown promise, they have only succeeded in modulating latency in a fraction of the latent HIV reservoir, suggesting that the mechanisms controlling HIV latency are not completely understood, and that comprehensive latency modulation will require targeting of multiple latency maintenance pathways. We show here that the transcriptional co-activator and the central mediator of canonical Wnt signaling, β-catenin, inhibits HIV transcription in CD4+ T cells via TCF-4 LTR binding sites. Further, we show that inhibiting the β-catenin pathway reactivates HIV in a primary TCM cell model of HIV latency, primary cells from cART-controlled HIV donors, and in CD4+ latent cell lines. β-catenin inhibition or activation also enhanced or inhibited the activity of several classes of HIV latency reversing agents, respectively, in these models, with significant synergy of β-catenin and each LRA class tested. In sum, we identify β-catenin as a novel regulator of HIV latency in vitro and ex vivo, adding new therapeutic targets that may be combined for comprehensive HIV latency modulation in HIV cure efforts.

Smart design approaches for orally administered lipophilic prodrugs to promote lymphatic transport

Challenges to effective delivery of drugs following oral administration has attracted growing interest over recent decades. Small molecule drugs (<1000 Da) are generally absorbed across the gastrointestinal tract into the portal blood and further transported to the systemic circulation via the liver. This can result in a significant reduction to the oral bioavailability of drugs that are metabolically labile and ultimately lead to ineffective exposure and treatment. Targeting drug delivery to the intestinal lymphatics is attracting increased attention as an alternative route of drug transportation providing multiple benefits. These include bypassing hepatic first-pass metabolism and selectively targeting disease reservoirs residing within the lymphatic system. The particular physicochemical requirements for drugs to be able to access the lymphatics after oral delivery include high lipophilicity (logP>5) and high long-chain triglyceride solubility (> 50 mg/g), properties required to enable drug association with the lipoprotein transport pathway. The majority of small molecule drugs, however, are not this lipophilic and therefore not substantially transported via the intestinal lymph. This has contributed to a growing body of investigation into prodrug approaches to deliver drugs to the lymphatic system by chemical manipulation. Optimised lipophilic prodrugs have the potential to increase lymphatic transport thereby improving oral pharmacokinetics via a reduction in first pass metabolism and may also target of disease-specific reservoirs within the lymphatics. This may provide advantages for current pharmacotherapy approaches for a wide array of pathological conditions, e.g. immune disease, cancer and metabolic disease, and also presents a promising approach for advanced vaccination strategies. In this review, specific emphasis is placed on medicinal chemistry strategies that have been successfully employed to design lipophilic prodrugs to deliberately enable lymphatic transport. Recent progress and opportunities in medicinal chemistry and drug delivery that enable new platforms for efficacious and safe delivery of drugs are critically evaluated.

Optimal Control of an HIV Model with Gene Therapy and Latency Reversing Agents

In this paper, we study the dynamics of HIV under gene therapy and latency reversing agents. While previous works modeled either the use of gene therapy or latency reversing agents, we consider the effects of a combination treatment strategy. For constant treatment controls, we establish global stability of the disease-free equilibrium and endemic equilibrium based on the value of R0. We then consider time-dependent controls and formulate an associated optimal control problem that emphasizes reduction of the latent reservoir. Characterizations for the optimal control profiles are found using Pontryagin’s Maximum Principle. We perform numerical simulations of the optimal control model using the fourth-order Runge–Kutta forward-backward sweep method. We find that a combination treatment of gene therapy with latency reversing agents provides better remission times than gene therapy alone. We conclude with a discussion of our findings and future work.

NK-B cell cross talk induces CXCR5 expression on natural killer cells

B cell follicles (BCFs) in lymph nodes (LNs) are generally exempt of CD8⁺ T and NK cells. African green monkeys (AGMs), a natural host of simian immunodeficiency virus (SIV), display NK cell-mediated viral control in BCF. NK cell migration into BCF in chronically SIVagm-infected AGM is associated with CXCR5⁺ NK cells. We aimed to identify the mechanism leading to CXCR5 expression on NK cells. We show that CXCR5⁺ NK cells in LN were induced following SIVagm infection. CXCR5⁺ NK cells accumulated preferentially in BCF with proliferating B cells. Autologous NK-B cell co-cultures in transwell chambers induced CXCR5⁺ NK cells. Transcriptome analysis of CXCR5⁺ NK cells revealed expression of bcl6 and IL6R. IL-6 induced CXCR5 on AGM and human NK cells. IL6 mRNA was detected in LN at higher levels during SIVagm than SIVmac infection and often produced by plasma cells. Our study reveals a mechanism of B cell-dependent NK cell regulation.

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IL-6 can induce CXCR5 on NK cells

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CXCR5⁺ NK cells expressed high levels of bcl6 and IL6R

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More IL-6⁺ plasmablast/plasma cells in lymph nodes in SIVagm than SIVmac infection

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B cells participate in the regulation of NK cell migration into BCF

Design, synthesis, and mechanistic investigations of phenylalanine derivatives containing a benzothiazole moiety as HIV-1 capsid inhibitors with improved metabolic stability

Further clinical development of PF74, a lead compound targeting HIV-1 capsid, is impeded by low antiviral activity and inferior metabolic stability. By modifying the benzene (region I) and indole of PF74, we identified two potent compounds (7m and 7u) with significantly improved metabolic stability. Compared to PF74, 7u displayed greater metabolic stability in human liver microsomes (HLMs) with half-life (t_1/2) 109-fold that of PF74. Moreover, mechanism of action (MOA) studies demonstrated that 7m and 7u effectively mirrored the MOA of compounds that interact within the PF74 interprotomer pocket, showing direct and robust interactions with recombinant CA, and 7u displaying antiviral effects in both the early and late stages of HIV-1 replication. Furthermore, MD simulation corroborated that 7u was bound to the PF74 binding site, and the results of the online molinspiration software predicted that 7m and 7u had desirable physicochemical properties. Unexpectedly, this series of compounds exhibited better antiviral activity than PF74 against HIV-2, represented by compound 7m whose anti-HIV-2 activity was almost 5 times increased potency over PF74. Therefore, we have rationally redesigned the PF74 chemotype to inhibitors with novel structures and enhanced metabolic stability in this study. We hope that these new compounds can serve as a blueprint for developing a new generation of HIV treatment regimens.

Autophagy-dependent glutaminolysis drives superior IL21 production in HIV-1-specific CD4 T cells

The maintenance of a strong IL21 production in memory CD4 T cells, especially in HIV-1-specific cells, represents a major correlate of natural immune protection against the virus. However, the molecular mechanisms underlying IL21 production during HIV-1 infection, which is only elevated among the naturally protected elite controllers (EC), are still unknown. We recently found out that lipophagy is a critical immune mediator that control an antiviral metabolic state following CD8A T cell receptor engagement, playing an important role in the natural control of HIV-1 infection. This led us to investigate whether the beneficial role of a strong macroautophagy/autophagy, could also be used to ensure effective IL21 production as well. Herein, we confirm that after both polyclonal and HIV-1-specific activation, memory CD4 T cells (Mem) from EC display enhanced activity of the autophagy-mediated proteolysis compared to ART. Our results indicate that the enhanced autophagy activity in EC was controlled by the energy-sensing PRKAA1 (protein kinase AMP-activated catalytic subunit alpha 1). We further confirmed the critical role of the autophagy-mediated proteolysis in the strong IL21 production in EC by using BECN1 gene silencing as well as protease, PRKAA1, and lysosomal inhibitors. Finally, we established that high autophagy-mediated proteolysis in EC fuels their cellular rates of mitochondrial respiration due to glutaminolysis. Our data confirm the critical role of autophagy in dictating the metabolic input, which is required not only to ensure protective cytotoxic CD8A T cell responses, but also to provide strong IL21 production among antiviral CD4 T cells.Abbreviations: AKG: alpha-ketoglutarate; ART: patients under antiretroviral therapy; ATG7: autophagy related 7; BaF: bafilomycin A₁; BECN1: beclin 1; Chloro.: chloroquine; EC: elite controllers; EIF4EBP1: eukaryotic translation initiation factor 4E binding protein 1; FOXO3: forkhead box O3; GLS: glutaminase; GLUD1: glutamate dehydrogenase 1; HIV^neg: HIV-1-uninfected control donors; IFNG/IFN-γ: interferon gamma; IL21: interleukin 21; MTOR: mechanistic target of rapamycin kinase; PBMC: peripheral blood mononuclear cells; PRKAA1: protein kinase AMP-activated catalytic subunit alpha 1; SQSTM1: sequestosome 1; TCA: tricarboxylic acid cycle; ULK1: unc-51 like autophagy activating kinase.

Targeting and Understanding HIV Latency: The CRISPR System against the Provirus

The presence of latently infected cells and reservoirs in HIV-1 infected patients constitutes a significant obstacle to achieve a definitive cure. Despite the efforts dedicated to solve these issues, the mechanisms underlying viral latency are still under study. Thus, on the one hand, new strategies are needed to elucidate which factors are involved in latency establishment and maintenance. On the other hand, innovative therapeutic approaches aimed at eradicating HIV infection are explored. In this context, advances of the versatile CRISPR-Cas gene editing technology are extremely promising, by providing, among other advantages, the possibility to target the HIV-1 genome once integrated into cellular DNA (provirus) and/or host-specific genes involved in virus infection/latency. This system, up to now, has been employed with success in numerous in vitro and in vivo studies, highlighting its increasing significance in the field. In this review, we focus on the progresses made in the use of different CRISPR-Cas strategies to target the HIV-1 provirus, and we then discuss recent advancements in the use of CRISPR screens to elucidate the role of host-specific factors in viral latency.

Assessing proviral competence: current approaches to evaluate HIV-1 persistence

PURPOSE OF REVIEW

Despite decades of suppressive antiretroviral therapy (ART), HIV-1 reservoirs persist and fuel viral rebound if therapy is interrupted. The persistence of viral reservoirs in infected individuals is the main obstacle to achieving HIV-1 eradication or a long-term remission. Accurate assessment of the viral reservoir size is necessary for monitoring the effectiveness of the curative interventions. Here, we review the recent progress in the development of assays to measure HIV-1 persistence, highlighting their key advantages and limitations.

RECENT FINDINGS

To estimate the viral reservoir size, a number of assays have been developed that assess different aspects of HIV-1 persistence in ART-treated individuals. These include viral outgrowth assays to measure proviral replication competence, sequencing-based assays to measure genetic intactness of HIV-1 proviruses, and diverse techniques that measure the ability of proviruses to produce viral RNA and/or proteins (transcription and translation competence), with or without ex vivo stimulation. Recent years have seen the development of next-generation reservoir assays that, in addition to measuring viral persistence markers, assess the proviral integration sites and characterize the HIV-1 reservoir cells on the single-cell level.

SUMMARY

Although no assay yet can measure the HIV-1 reservoir with 100% accuracy, recent technical advances allow reliable estimation of its size and composition.

The accumulation of plasma acylcarnitines are associated with poor immune recovery in HIV-infected individuals

BACKGROUND

Antiretroviral therapy (ART) can reduce opportunistic infections and mortality rates among individuals infected with human immunodeficiency virus (HIV); however, some HIV-infected individuals exhibit poor immune recovery after ART. Hence, we explored the association between metabolome profiles and immune recovery in HIV-infected individuals following ART.

METHODS

An untargeted metabolomics approach was used to analyze plasma samples from 18 HIV-negative individuals and 20 HIV-infected individuals, including 10 immunological non-responders (INR, CD4⁺ T cell rise < 100 cells/μl) and 10 immunological responders (IR, CD4⁺ T cell rise > 300 cells/μl) after 2 years of ART. These individuals were followed for the next 6 years and viral loads and CD4⁺ T cell count were measured regularly. Orthogonal projection on latent structures discriminant analysis (OPLS-DA), ANOVA, correlation, receiver operating characteristic (ROC), and survival analyses were used for selection of discriminant metabolites.

RESULTS

Eighteen lipid metabolites were identified which could distinguish among control, INR, and IR groups. Among them, myristoylcarnitine (MC), palmitoylcarnitine (PC), stearoylcarnitine (SC), and oleoylcarnitine (OC) were significantly elevated in INR plasma samples compared with those from the IR and control groups and were negatively associated with CD4⁺ T cell count. Additionally, ROC analysis using a combination of MC, PC, SC, and OC had high sensitivity and specificity for differentiating INR from IR (AUC = 0.94). Finally, survival analysis for the combination of MC, PC, SC, and OC demonstrated that it could predict CD4⁺ T cell count in patients undergoing long-term ART.

CONCLUSIONS

High levels of lipid metabolites, MC, PC, SC, and OC are associated with poor immune recovery in patients receiving ART and these data provide potential new insights into immune recovery mechanisms.

Addressing an HIV cure in LMIC

HIV-1 persists in infected individuals despite years of antiretroviral therapy (ART), due to the formation of a stable and long-lived latent viral reservoir. Early ART can reduce the latent reservoir and is associated with post-treatment control in people living with HIV (PLWH). However, even in post-treatment controllers, ART cessation after a period of time inevitably results in rebound of plasma viraemia, thus lifelong treatment for viral suppression is indicated. Due to the difficulties of sustained life-long treatment in the millions of PLWH worldwide, a cure is undeniably necessary. This requires an in-depth understanding of reservoir formation and dynamics. Differences exist in treatment guidelines and accessibility to treatment as well as social stigma between low- and-middle income countries (LMICs) and high-income countries. In addition, demographic differences exist in PLWH from different geographical regions such as infecting viral subtype and host genetics, which can contribute to differences in the viral reservoir between different populations. Here, we review topics relevant to HIV-1 cure research in LMICs, with a focus on sub-Saharan Africa, the region of the world bearing the greatest burden of HIV-1. We present a summary of ART in LMICs, highlighting challenges that may be experienced in implementing a HIV-1 cure therapeutic. Furthermore, we discuss current research on the HIV-1 latent reservoir in different populations, highlighting research in LMIC and gaps in the research that may facilitate a global cure. Finally, we discuss current experimental cure strategies in the context of their potential application in LMICs.

Analytical Treatment Interruption in HIV Trials: Statistical and Study Design Considerations

Purpose of Review

Analytical treatment interruption (ATI) remains an essential component in clinical studies investigating novel agents or combination treatment strategies aiming to induce HIV treatment-free remission or long-term viral control. We provide an overview on key study design aspects of ATI trials from the perspective of statisticians.

Recent Findings

ATI trial designs have evolved towards shorter treatment interruption phases and more frequent viral load monitoring aiming to reduce prolonged viremia risks. Criteria for ART resumption have evolved as well. Common outcome measures in modern ATI trials include time to viral rebound, viral control, and viral set point.

Summary

Design of the ATI component in HIV clinical trials is driven by the scientific question and the mechanism of action of the intervention being investigated.

Photoinduced Photosensitizer-Antibody Conjugates Kill HIV Env-Expressing Cells, Also Inactivating HIV

HIV-infected cells persist for decades in patients administered with antiretroviral therapy (ART). Meanwhile, an alarming surge in drug-resistant HIV viruses has been occurring. Addressing these issues, we propose the application of photoimmunotherapy (PIT) against not only HIV Env-expressing cells but also HIV. Previously, we showed that a human anti-gp41 antibody (7B2) conjugated to cationic or anionic photosensitizers (PSs) could specifically target and kill the HIV Env-expressing cells. Here, our photolysis studies revealed that the binding of photoimmunoconjugates (PICs) on the membrane of HIV Env-expressing cells is sufficient to induce necrotic cell death due to physical damage to the membrane by singlet oxygen, which is independent of the type of PSs. This finding persuaded us to study the virus photoinactivation of PICs using two HIV-1 strains, X4 HIV-1 NL4-3 and JR-CSF virus. We observed that the PICs could destroy the viral strains, probably via physical damage on the HIV envelope. In conclusion, we report the application of PIT as a possible dual-tool for HIV immunotherapy and ART by killing HIV-expressing cells and cell-free HIV, respectively.

Emerging Role of Nef in the Development of HIV Associated Neurological Disorders

Despite adherence to treatment, individuals living with HIV have an increased risk for developing cognitive impairments, referred to as HIV-associated neurological disorders (HAND). Due to continued growth in the HIV population, particularly amongst the aging cohort, the neurobiological mechanisms of HAND are increasingly relevant. Similar to other viral proteins (e.g. Tat, Gp120, Vpr), the Negative Factor (Nef) is associated with numerous adverse effects in the CNS as well as cognitive impairments. In particular, emerging data indicate the consequences of Nef may be facilitated by the modulation of cellular autophagy as well as its inclusion into extracellular vesicles (EVs). The present review examines evidence for the molecular mechanisms by which Nef might contribute to neuronal dysfunction underlying HAND, with a specific focus on autophagy and EVs. Based on the these data, we propose an integrated model by which Nef may contribute to underlying neuronal dysfunction in HAND and highlight potentially novel therapeutic targets for HAND. Graphical abstract.

The Interplay of HIV and Autophagy in Early Infection

HIV/AIDS is still a global threat despite the notable efforts made by the scientific and health communities to understand viral infection, to design new drugs or to improve existing ones, as well as to develop advanced therapies and vaccine designs for functional cure and viral eradication. The identification and analysis of HIV-1 positive individuals that naturally control viral replication in the absence of antiretroviral treatment has provided clues about cellular processes that could interact with viral proteins and RNA and define subsequent viral replication and clinical progression. This is the case of autophagy, a degradative process that not only maintains cell homeostasis by recycling misfolded/old cellular elements to obtain nutrients, but is also relevant in the innate and adaptive immunity against viruses, such as HIV-1. Several studies suggest that early steps of HIV-1 infection, such as virus binding to CD4 or membrane fusion, allow the virus to modulate autophagy pathways preparing cells to be permissive for viral infection. Confirming this interplay, strategies based on autophagy modulation are able to inhibit early steps of HIV-1 infection. Moreover, autophagy dysregulation in late steps of the HIV-1 replication cycle may promote autophagic cell-death of CD4⁺ T cells or control of HIV-1 latency, likely contributing to disease progression and HIV persistence in infected individuals. In this scenario, understanding the molecular mechanisms underlying HIV/autophagy interplay may contribute to the development of new strategies to control HIV-1 replication. Therefore, the aim of this review is to summarize the knowledge of the interplay between autophagy and the early events of HIV-1 infection, and how autophagy modulation could impair or benefit HIV-1 infection and persistence, impacting viral pathogenesis, immune control of viral replication, and clinical progression of HIV-1 infected patients.

Reversal of Viral Latency and Induction of Gag-Specific T-Cell Responses in HIV-1-Infected Adults Through Cyclic Treatment Interruption of Rosuvastatin: A Proof-of-Concept Study

BACKGROUND

HIV-1 infection remains incurable through combination antiretroviral therapy. Previous studies have shown statins have immunomodulatory effects, and interruption of statins may cause an immune rebound.

METHODS

In this proof-of-concept study, we longitudinally assessed the impact of immune rebound by cyclic treatment-interruption (CTI) of rosuvastatin on the reversal of HIV latency. The HIV-1-infected persons with stable viral control were considered to be enrolled for CTI of rosuvastatin with a fixed 12-week interval for 72 weeks (3 treatment-interruption cycles). HIV-1 Gag-specific T-cell responses, cell-associated RNA, and proviral DNA were determined.

RESULTS

From Feb 2017 to Dec 2019, 10 subjects were enrolled. During the 72-week follow-up, their CD4+ T-cell counts did not significantly change, and plasma HIV RNA remained undetectable. Transient but remarkable increases in levels of cell-associated RNA, Gag-specific interferon-γ production from CD4+ T cells and Gag-specific CD8+ cytotoxic capacity were detected shortly after stopping rosuvastatin in every cycle of CTI of rosuvastatin. Furthermore, there was a 2.63-fold reduction (range, 1.41-4.82) in proviral DNA levels (P = 0.005) during the 72-week follow-up. A significant linear association was demonstrated between their nadir CD4+ T-cell counts and the fold decrease in proviral DNA levels (R = 0.81, P = 0.004).

CONCLUSION

It may be possible to reverse viral latency in CD4+ T cells, activate Gag-specific T cells, and reduce viral reservoir size through CTI of rosuvastatin in HIV-1-infected subjects with stable combination antiretroviral therapy, especially in those with nadir CD4+ T-cell counts > 350 cells/μL.