Gliotoxin, identified from a screen of fungal metabolites, disrupts 7SK snRNP, releases P-TEFb, and reverses HIV-1 latency

Liquid-liquid phase separation of LARP7 restrains HIV-1 replication

HIV-1 initiates replication by its transactivator Tat, hijacking the positive transcription elongation factor b (P-TEFb) in the host cell. Most P-TEFb is maintained in an inactive state by 7SK snRNP until it is brought to the transcription initiation complex by cellular or viral transactivators that accelerate transcription and facilitate the production of full-length viral transcripts. Here, we report that HIV-1 infection triggers liquid-liquid phase separation of LARP7, a central component of 7SK snRNP. Tat is incorporated into HIV-1-induced LARP7 condensates after infection. Conserved lysine residues in the intrinsically disordered region of LARP7 are essential for both its phase separation and the inhibition of Tat-mediated transcription. These findings identify a mechanism wherein P-TEFb and Tat are sequestered within LARP7 condensates, restraining HIV-1 transcription.

Transcriptome-proteome integration analysis identifies elevated expression of LARP7 promoting the tumorigenesis and development of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the digestive tract, with c-kit and PDGFRA mutations being the primary causes. However, GIST pathogenesis is not still fully understood. Differential expression analysis, Univariate Cox regression and Kaplan-Meier curves were utilized to screen for up-regulated and prognostically relevant genes. The expression distribution was compared across various demographics and clinical groups. The relationship between gene expression and cytokine pathway activation was assessed via CytoSig. Immune cell infiltration was analyzed using TIMER2.0. Four paired GIST and adjacent normal tissues were collected to validate the expression trend. CCK8 assays and scratch wound healing assays were conducted in GIST-T1 and GIST-882 cells. Results indicated that LARP7 was up-regulated in GISTs at both mRNA and protein levels. This elevated expression was associated with poor prognosis, particularly in GISTs located in the small intestine and those with larger tumor sizes. LARP7 was implicated in the expression of IFN-induced genes and the negative regulation of viral processes. Predictions of cytokine pathways supported these findings, and immune cell infiltration analysis revealed a higher presence of CD8+ T cells in GISTs with high LARP7 expression. The lncRNA (H19 or LINC00665)-miRNA(hsa-miR-138-5p) axis targeted LARP7. Furthermore, LARP7 was elevated in imatinib-resistant GISTs, with some other drugs predicted to aid in therapy. LARP7 knockdown resulted in reduced proliferation and migration of GIST-T1 and GIST-882 cells. Overall, high expression of LARP7 correlates with poor prognosis in GISTs, highlighting its potential as a therapeutic target.

Release of P-TEFb from the Super Elongation Complex promotes HIV-1 latency reversal

The persistence of HIV-1 in long-lived latent reservoirs during suppressive antiretroviral therapy (ART) remains one of the principal barriers to a functional cure. Blocks to transcriptional elongation play a central role in maintaining the latent state, and several latency reversal strategies focus on the release of positive transcription elongation factor b (P-TEFb) from sequestration by negative regulatory complexes, such as the 7SK complex and BRD4. Another major cellular reservoir of P-TEFb is in Super Elongation Complexes (SECs), which play broad regulatory roles in host gene expression. Still, it is unknown if the release of P-TEFb from SECs is a viable latency reversal strategy. Here, we demonstrate that the SEC is not required for HIV-1 replication in primary CD4+ T cells and that a small molecular inhibitor of the P-TEFb/SEC interaction (termed KL-2) increases viral transcription. KL-2 acts synergistically with other latency reversing agents (LRAs) to reactivate viral transcription in several cell line models of latency in a manner that is, at least in part, dependent on the viral Tat protein. Finally, we demonstrate that KL-2 enhances viral reactivation in peripheral blood mononuclear cells (PBMCs) from people living with HIV (PLWH) on suppressive ART, most notably in combination with inhibitor of apoptosis protein antagonists (IAPi). Taken together, these results suggest that the release of P-TEFb from cellular SECs may be a novel route for HIV-1 latency reactivation.

Effective in vivo reactivation of HIV-1 latency reservoir via oral administration of EK-16A-SNEDDS

The latent reservoir of human immunodeficiency virus (HIV) is a major obstacle in the treatment of acquired immune deficiency syndrome (AIDS). The "shock and kill" strategy has emerged as a promising approach for clearing HIV latent reservoirs. However, current latency-reversing agents (LRAs) have limitations in effectively and safely activating the latent virus and reducing the HIV latent reservoirs in clinical practice. Previously, EK-16A was extracted from Euphorbia kansui, which had the effect of interfering with the HIV-1 latent reservoir and inhibiting HIV-1 entry. Nevertheless, there is no suitable and efficient EK-16A oral formulation for in vivo delivery and clinical use. In this study, an oral EK-16A self-nanoemulsifying drug delivery system (EK-16A-SNEDDS) was proposed to "shock" the HIV-1 latent reservoir. This system aims to enhance the bioavailability and delivery of EK-16A to various organs. The composition of EK-16A-SNEDDS was optimized through self-emulsifying grading and ternary phase diagram tests. Cell models, pharmacokinetic experiments, and pharmacodynamics in HIV-1 latent cell transplant animal models suggested that EK-16A-SNEDDS could be absorbed by the gastrointestinal tract and enter the blood circulation after oral administration, thereby reaching various organs to activate latent HIV-1. The prepared EK-16A-SNEDDS demonstrated safety and efficacy, exhibited high clinical experimental potential, and may be a promising oral preparation for eliminating HIV-1 latent reservoirs.

Anti-HIV Activity and Immunomodulatory Properties of Fractionated Crude Extracts of Alternaria alternata

Developing new anti-human immunodeficiency virus (HIV) drug candidates that target different sites in HIV-1 replication, with better resistance profiles and lower drug toxicity, is essential to eradicating HIV. This study investigated the potential of fractionated crude extracts of Alternaria alternata as immunomodulatory or anti-HIV drug candidates. Solid-phase extraction (SPE) was used to fractionate A. alternata PO4PR2 using three different columns: MAX (Mixed-mode, strong Anion-eXchange), MCX (Mixed-mode, strong Cation-eXchange), and HLB (Hydrophilic-Lipophilic Balance) with methanol gradient methods (5%, 45%, and 95%). An MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay was used to assess the cell viability and cytotoxicity of the fractionated crude extract A. alternata PO4PR2 in the TZM-bl cell lines. This was followed by a luciferase-based antiviral assay to assess the antiviral activity of A. alternata PO4PR2. A time of addition (TOA) assay was performed to ascertain the mechanism of inhibition employed by the fractionated crude extract of A. alternata PO4PR2 in the HIV life cycle. The p24 titer was determined using an ELISA, while a luciferase-based antiviral assay was used to evaluate the HIV percentage inhibition for different HIV-1 replication cycles. The TOA assay was established using antiviral drugs that target different sites in the HIV replication cycle. These included maraviroc, azidothymidine, raltegravir, and amprenavir. The immunomodulatory effect of the fractionated crude extracts on CD4+ T cells was measured by a flow cytometric analysis, for which fluorochrome-labelled monoclonal antibodies were used as markers for activation (CD38 and HLA-DR) and exhaustion (PD-1). The MCX fraction demonstrated a more significant anti-HIV inhibition than that of the fractions generated in other columns, with an IC50 of 0.3619 µg/mL, an HIV inhibition of 77%, 5% HLB (IC50: 0.7232 µg/mL; HIV inhibition of 64%), and 5% MAX (IC50: 5.240 µg/mL; HIV inhibition of 67%). It was evident from the time of addition data that the crude extract and the 5% MCX fraction inhibited viral binding (68%), reverse transcription (75%), integration (98%), and proteolysis (77%). It was shown that A. alternata (the MCX fraction) have a significant inhibitory effect on reverse transcription (75% HIV inhibition) and integration (100% HIV inhibition). The 5% MCX (p = 0.0062), 5% HLB (p = 0.0269), and 5% MAX (p = 0.0117) fractionated A. alternata crude extracts had low levels of CD4+ T cell (CD38 + HLA-DR+) activation compared to those of the AZT treatment, while CD4+ T cell activation was insignificant. The 5% MAX and HLB A. alternata fractions may possess immunomodulatory compounds with less anti-HIV-1 activity. A. alternata could be a key source of innovative anti-HIV drugs with immunomodulatory characteristics.

Release of P-TEFb from the Super Elongation Complex promotes HIV-1 latency reversal

The persistence of HIV-1 in long-lived latent reservoirs during suppressive antiretroviral therapy (ART) remains one of the principal barriers to a functional cure. Blocks to transcriptional elongation play a central role in maintaining the latent state, and several latency reversal strategies focus on the release of positive transcription elongation factor b (P-TEFb) from sequestration by negative regulatory complexes, such as the 7SK complex and BRD4. Another major cellular reservoir of P-TEFb is in Super Elongation Complexes (SECs), which play broad regulatory roles in host gene expression. Still, it is unknown if the release of P-TEFb from SECs is a viable latency reversal strategy. Here, we demonstrate that the SEC is not required for HIV-1 replication in primary CD4+ T cells and that a small molecular inhibitor of the P-TEFb/SEC interaction (termed KL-2) increases viral transcription. KL-2 acts synergistically with other latency reversing agents (LRAs) to reactivate viral transcription in several cell line models of latency in a manner that is, at least in part, dependent on the viral Tat protein. Finally, we demonstrate that KL-2 enhances viral reactivation in peripheral blood mononuclear cells (PBMCs) from people living with HIV on suppressive ART, most notably in combination with inhibitor of apoptosis protein antagonists (IAPi). Taken together, these results suggest that the release of P-TEFb from cellular SECs may be a novel route for HIV-1 latency reactivation.

Epigenetic Induction of Secondary Metabolites Production in Endophytic Fungi Penicillium chrysogenum and GC-MS Analysis of Crude Metabolites with Anti-HIV-1 Activity

The continuous burden of human immunodeficiency virus-1 in Sub-Saharan Africa, coupled with the inability of antiretroviral agents to eradicate HIV-1 from viral reservoirs, the potential risks of drug resistance development, and the development of adverse effects, emphasizes the need to develop a new class of HIV-1 inhibitors. Here, we cultivated four endophytic fungal isolates from a medicinal plant, Albizia adianthifolia with the addition of small epigenetic modifiers, sodium butyrate, and valproic acid, to induce the expression of biosynthetic gene clusters encoding active secondary metabolites with probable anti-HIV activities. We identified a non-toxic crude extract of the endophytic fungus Penicillium chrysogenum treated with sodium butyrate to possess significantly greater anti-HIV activity than the untreated extracts. Penicillium chrysogenum P03MB2 showed anti-HIV activity with an IC₅₀ of 0.6024 µg/mL compared to untreated fungal crude extract (IC₅₀ 5.053 µg/mL) when treated with sodium butyrate. The profile of secondary metabolite compounds from the bioactive, partially purified extracts were identified by gas chromatography-mass spectrometry (GC-MS), and more bioactive compounds were detected in treated P. chrysogenum P03MB2 fractions than in untreated fractions. Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro (13.64%), cyclotrisiloxane, hexamethyl (8.18%), cyclotetrasiloxane, octamethyl (7.23%), cyclopentasiloxane, decamethyl (6.36%), quinoline, 1,2-dihydro-2,24-trimethyl (5.45%), propanenitrile (4.55%), deca-6,9-diene (4.55%), dibutyl phthalate (4.55%), and silane[1,1-dimethyl-2-propenyl)oxy]dimethyl (2.73%) were the most abundant compounds. These results indicate that treatment of endophytic fungi with small epigenetic modifiers enhances the secretion of secondary metabolites with stronger anti-HIV-1 properties, acknowledging the feasibility of epigenetic modification as an innovative approach for the discovery of cryptic fungal metabolites which can be developed into therapeutic compounds.

Developments in Exploring Fungal Secondary Metabolites as Antiviral Compounds and Advances in HIV-1 Inhibitor Screening Assays

The emergence of drug-resistant Human Immunodeficiency Virus-1 strains against anti-HIV therapies in the clinical pipeline, and the persistence of HIV in cellular reservoirs remains a significant concern. Therefore, there is a continuous need to discover and develop new, safer, and effective drugs targeting novel sites to combat HIV-1. The fungal species are gaining increasing attention as alternative sources of anti-HIV compounds or immunomodulators that can escape the current barriers to cure. Despite the potential of the fungal kingdom as a source for diverse chemistries that can yield novel HIV therapies, there are few comprehensive reports on the progress made thus far in the search for fungal species with the capacity to produce anti-HIV compounds. This review provides insights into the recent research developments on natural products produced by fungal species, particularly fungal endophytes exhibiting immunomodulatory or anti-HIV activities. In this study, we first explore currently existing therapies for various HIV-1 target sites. Then we assess the various activity assays developed for gauging antiviral activity production from microbial sources since they are crucial in the early screening phases for discovering novel anti-HIV compounds. Finally, we explore fungal secondary metabolites compounds that have been characterized at the structural level and demonstrate their potential as inhibitors of various HIV-1 target sites.

Medicinal Chemistry of Anti-HIV-1 Latency Chemotherapeutics: Biotargets, Binding Modes and Structure-Activity Relationship Investigation

The existence of latent viral reservoirs (LVRs), also called latent cells, has long been an acknowledged stubborn hurdle for effective treatment of HIV-1/AIDS. This stable and heterogeneous reservoir, which mainly exists in resting memory CD4⁺ T cells, is not only resistant to highly active antiretroviral therapy (HAART) but cannot be detected by the immune system, leading to rapid drug resistance and viral rebound once antiviral treatment is interrupted. Accordingly, various functional cure strategies have been proposed to combat this barrier, among which one of the widely accepted and utilized protocols is the so-called 'shock-and-kill' regimen. The protocol begins with latency-reversing agents (LRAs), either alone or in combination, to reactivate the latent HIV-1 proviruses, then eliminates them by viral cytopathic mechanisms (e.g., currently available antiviral drugs) or by the immune killing function of the immune system (e.g., NK and CD8+ T cells). In this review, we focuse on the currently explored small molecular LRAs, with emphasis on their mechanism-directed drug targets, binding modes and structure-relationship activity (SAR) profiles, aiming to provide safer and more effective remedies for treating HIV-1 infection.

Ten decadal advances in fungal biology leading towards human well-being

Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being. In the current paper, we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research. These examples concern recently introduced drugs for the treatment of infections and neurological diseases; application of -OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production; as well as some highlights of mushroom cultivaton in Asia. Examples for new diagnostic tools in medical mycology and the exploitation of new candidates for therapeutic drugs, are also given. In addition, two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided. Some other areas where there have been and/or will be significant developments are also included. It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward many new fungal and fungus-derived products.

A synthetic resveratrol analog termed Q205 reactivates latent HIV-1 through activation of P-TEFb

The persistence of HIV-1 latent reservoir creates the major obstacle toward an HIV-1 cure. The "shock and kill" strategy aims to reverse HIV-1 proviral latency using latency-reversing agents (LRAs), thus boosting immune recognition and clearance to residual infected cells. Unfortunately, to date, none of these tested LRA candidates has been demonstrated effectiveness and/or safety in reactivation HIV-1 latency. The discovery and development of effective, safe and affordable LRA candidates are urgently needed for creating an HIV-1 functional cure. Here, we designed and synthesized a series of small-molecule phenoxyacetic acid derivatives based on the resveratrol scaffold and found one of them, named 5, 7-dimethoxy-2-(5-(methoxymethyl) furan-2-yl) quinazolin-4(3H)-one (Q205), effectively reactivated latent HIV-1 in latent HIV-1-infected cells without a corresponding increase in induction of potentially damaging cytokines. The molecular mechanism of Q205 is shown to increase the phosphorylation of the CDK9 T-loop at position Thr186, dissociate positive transcription elongation factor b (P-TEFb) from BRD4, and promote the Tat-mediated HIV-1 transcription and RNA polymerase II (RNAPII) C-terminal domain (CTD) on Ser (CTD-Ser2P) to bind to the HIV promoter. This study provides a unique insight into resveratrol modified derivatives as promising leads for preclinical LRAs, which in turn may help toward inhibitor design and chemical optimization for improving HIV-1 shock-and kill-based efforts.

A Two-Color Haploid Genetic Screen Identifies Novel Host Factors Involved in HIV-1 Latency

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.

The Toxic Mechanism of Gliotoxins and Biosynthetic Strategies for Toxicity Prevention

Gliotoxin is a kind of epipolythiodioxopiperazine derived from different fungi that is characterized by a disulfide bridge. Gliotoxins can be biosynthesized by a gli gene cluster and regulated by a positive GliZ regulator. Gliotoxins show cytotoxic effects via the suppression the function of macrophage immune function, inflammation, antiangiogenesis, DNA damage by ROS production, peroxide damage by the inhibition of various enzymes, and apoptosis through different signal pathways. In the other hand, gliotoxins can also be beneficial with different doses. Low doses of gliotoxin can be used as an antioxidant, in the diagnosis and treatment of HIV, and as an anti-tumor agent in the future. Gliotoxins have also been used in the control of plant pathogens, including Pythium ultimum and Sclerotinia sclerotiorum. Thus, it is important to elucidate the toxic mechanism of gliotoxins. The toxic mechanism of gliotoxins and biosynthetic strategies to reduce the toxicity of gliotoxins and their producing strains are summarized in this review.

Launching a multidisciplinary European collaboration towards a cure for HIV: The EU2Cure Consortium

We felt the urgency to launch the EU2Cure Consortium to support research and find a cure for the human immunodeficiency virus (HIV) infection through intensified collaboration within Europe. This consortium is open to stakeholders on cure in Europe from academia and the community to connect. The aim of this consortium is to intensify the research collaboration amongst European HIV cure groups and the community and facilitate interactions with other academic and community cure consortia, private parties, and policy makers. Our main aim is to create a European research agenda, data sharing, and development of best practice for clinical and translational science to achieve breakthroughs with clinically feasible HIV cure strategies. This consortium should also enable setting up collaborative studies accessible to a broader group of people living with HIV. Besides reservoir studies, we have identified three overlapping scientific interests in the consortium that provide a starting point for further research within a European network: developing “shock and kill” cure strategies, defining HIV cure biomarkers, and connecting cure cohorts. This strategy should aid stakeholders to sustain progress in HIV cure research regardless of coincidental global health or political crises.

Selective cell death in HIV-1-infected cells by DDX3 inhibitors leads to depletion of the inducible reservoir

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.