Research progress and perspectives of dual-target inhibitors

The occurrence and development of diseases are complex, and single-target drugs that affect only a single target or pathway often fail to achieve the expected therapeutic effect. The simultaneous effect on two key targets could not only increase patient tolerance but also accelerate disease remission. Dual-target inhibitors have already been studied the most intensively in the development of dual-target drugs. This article briefly introduces the function of drug therapy targets, and mainly summarizes the design strategies and research progress of dual-target inhibitors in neurodegenerative diseases, infectious diseases, metabolic diseases and cardiovascular diseases.

A patent review of hepatitis B virus core protein allosteric modulators (2019-present)

INTRODUCTION

The hepatitis B virus (HBV) core protein is a significant therapeutic target due to its essential role in HBV replication. Over the past five years, numerous structurally unique CpAMs have been patented. However, no compounds have been approved due to various issues such as poor pharmacokinetics (PK) and hepatotoxicity. As a result, there is an urgent need to develop novel CpAMs without these limitations.

AREAS COVERED

This review provides a comprehensive analysis of patents related to CpAMs from 2019 to the present, with the aim of delineating the chemical evolution that has occurred in the pursuit of more promising CpAMs. The sources of patent information included databases of the European Patent Office, the China Patent Office and the U.S.A. Patent Office, while relevant research articles were accessed through PubMed.

EXPERT OPINION

During the optimization of CpAMs, striking a good balance between activity and druggability usually poses a certain challenge while the emergence of drug resistance issues further complicates the development process. A comprehensive analysis of the structural features of CpAMs and identification of essential patterns in chemical evolution can reveal common principles that improve pharmacodynamic (PD) and PK profiles, thereby facilitating the discovery of next-generation CpAMs.

Bacterial reverse transcriptase synthesizes long poly-A-rich cDNA for antiphage defense

Prokaryotic defense-associated reverse transcriptases (DRTs) were recently identified with antiviral functions; however, their functional mechanisms remain largely unexplored. Here we show that DRT9 forms a hexameric complex with its upstream non-coding RNA (ncRNA) to mediate antiphage defense by inducing cell growth arrest via abortive infection. Upon phage infection, the phage-encoded ribonucleotide reductase NrdAB complex elevates intracellular dATP levels, activating DRT9 to synthesize long, poly-A-rich single-stranded cDNA, which likely sequesters the essential phage SSB protein and disrupts phage propagation. We further determined the cryo-electron microscopy structure of the DRT9-ncRNA hexamer complex, providing mechanistic insights into its cDNA synthesis. These findings highlight the diversity of RT-based antiviral defense mechanisms, expand our understanding of RT biological functions, and provide a structural basis for developing DRT9-based biotechnological tools.

Impact of training healthcare professionals in the detection and management of neuropsychiatric comorbidities in people with HIV: The CONECTAR project in Spain

INTRODUCTION

Although anxiety, depression and insomnia in people with HIV (PWH) are prevalent and have a major impact on clinical outcomes and quality of life, physicians fail to evaluate them routinely. The CONECTAR Project [Neuropsychiatric Comorbidity (NPC): Key to Antiretroviral Treatment] aimed to improve NPC clinical care in PWH in Spain by upskilling healthcare professionals (HCPs).

METHODS

A group of HCPs developed a training programme, supported by national and international guidelines, to improve expertise on detecting and managing NPCs in PWH. The programme was conducted through workshops for physicians and nurses in various Spanish regions from April to November 2023; survey questionnaires were administered to physicians before the commencement of training and 15 days after. Later, a workshop was held for nurses who manage NPCs in PWH.

RESULTS

The programme was completed by 64 physicians (22 had completed both questionnaires) and 11 nurses (no feedback obtained). Feedback from physicians reflected that the programme boosted awareness and self-perception of being more qualified, knowledgeable and able to use management tools and resources. Physicians also reported improved perception of time available for visits and more frequent enquiries about patients' NPC symptoms. Despite their satisfaction with the workshops, half of the physicians recognized the need for more training.

CONCLUSION

The CONECTAR Project was a successful training programme that was well received and valued by HCPs who routinely manage NPCs in PWH. Institutions involved in HCP training to manage anxiety, depression and insomnia more effectively in PWH should consider similar proposals to reinforce clinical practices.

Xerostomia and associated factors among adults with HIV on HAART attending voluntary counseling and testing (VCT) clinics in Dar Es Salaam

BACKGROUND

Adequate saliva quantity and quality are necessary for proper oral function and protection. Xerostomia, or dry mouth, is a common complaint among people living with HIV (PLHIV) which increases their risk of acquiring oral diseases. This study aimed to assess the magnitude of xerostomia and the associated factors in this group of patients.

METHODS

A descriptive cross-sectional hospital-based study was conducted among 420 PLHIV on highly active antiretroviral therapy (HAART) aged 18 years and above. Informed consent was obtained from the participants during data collection. The xerostomia was assessed using a questionnaire. Pearson's χ2 test was used to correlate independent (sociodemographic factors, oral health-related, and HIV-related factors) and dependent variables (xerostomia). Univariate and adjusted multinomial logistic regression were used to determine the odds ratio (OR) of xerostomia.

RESULTS

Xerostomia was observed in 36.3% of the respondents. The chi-square test showed a significantly higher proportion of xerostomia among the unemployed (p = 0.014), those who were HIV diagnosed up to five years (p = 0.014), and those having CD4+ counts ≥ 500 cells/ mm³ (p = 0.03). In multivariate analysis, higher odds of having xerostomia were found among participants with higher viral load (OR = 2.6; CI = 1.07-6.3), whereas lower odds were found among self-employed participants (OR = 0.48; CI = 0.28-0.82) and employed participants (OR = 0.52; CI = 0.27-0.98).

CONCLUSION

The prevalence of xerostomia is moderately high among PLHIV. Higher viral load and unemployment were the associated factors with xerostomia. Low CD4+ counts, duration of HAART use, and HAART regime were not associated with xerostomia.

Characterization of the gut microbiota in different immunological responses among PLWH

Despite gut microbial dysbiosis has been demonstrated in people living with HIV (PLWH), the association between gut microbial and inflammatory cytokines in PLWH with different immunoreaction to antiretroviral therapy (ART) is poorly understood. The purpose of this study is to explore between gut microbial and inflammatory cytokines in PLWH with different immunoreaction. 68 PLWH and 27 healthy controls(HCs) in Anhui Province were recruited from December 2021 to March 2022, including 35 immunological responders (IRs) (CD4+T-cell count ≥ 350 cells/µL) and 33 immunological non-responders (INRs) (CD4+T-cell count < 350 cells/µL) without comorbidities. Blood and stool samples were collected from all participants. Blood was used to detect microbial translocation biomarkers and inflammatory cytokines. Luminex Multifactor Detection Technology was performed to quantify plasma microbial translocation biomarkers and inflammation cytokines. Bacterial 16S rDNA sequencing was performed on stool samples. Microbiome sequencing revealed that the relative abundances of Fusobacteria, Actinobacteria, Verrucomicrobiaceae Acidaminococcaceae, Fusobacteriaceae and Megasphaera were greater, whereas Verrucomicrobia, Ruminococcaceae, Megamonas, Faecalibacterium, Roseburia and Dialister were more depleted in the HIV groups than those in the HCs (all P < 0.05). In the INRs group, the relative abundances of Actinomycetales, Micrococcaceae, Actinomyces, Intestinibacter, Rothia were greater (all P < 0.05), whereas Sutterellaceae, Parabacteroides, Veillonella, Butyricimonas resulted less abundant than in the IRs (all P < 0.05). TNF-ɑ are negatively correlated with the abundances of Dialiste (P = 0.022). CD54 are negatively correlated with Dialister and Subdoligranulum (P = 0.011). Recent and baseline CD4+T cells counts are directly proportional to Butyricimonas and Parabacteroides, while are inversely proportional with Veillonella and Rothia (all P < 0.05). Dysbiosis of the gut microbial might be one of the factors leading to the different immunoreaction and therapeutic effects of ART.

Dynamic Regulation of 5-Formylcytidine on tRNA

Post-transcriptional modifications on RNA play an important role in biological processes, but we lack an understanding of the molecular mechanisms underlying the function of many modifications. Here we characterize the distribution and dynamic regulation of 5-formylcytidine (f5C), a modification primarily found on tRNAs, across different cell lines, mouse tissues, and in response to environmental stress. We identify perturbation in bulk f5C levels using nucleoside LC-MS and quantify individual modification stoichiometry at the wobble base of mt-tRNA-Met and tRNA-Leu-CAA using nucleotide resolution f5C sequencing technology. Our studies show that f5C modifications on tRNAs are dynamic, and responsive to fluctuations in cellular iron levels and O2 concentration. Further, we show using a translation reporter assay that decoding of Leu UUA codons is impaired in cells lacking f5C, implicating f5C(m)34 on tRNA-Leu-CAA in wobble decoding. Together, our work illuminates dynamic epitranscriptomic mechanisms regulating protein translation in response to environment.

Therapeutic Potential of Tricyclic Pyridazinone-Based Molecules: An Overview

Pyridazin-3(2H)one-based molecules have always attracted the attention of medicinal chemists due to their different pharmacological properties. The incorporation of such nuclei in therapeutically active molecules either as monocyclic units or as fused bi- or tricyclic scaffolds results in a wide range of pharmacological effects such as anti-inflammatory, analgesic, anticancer, antimicrobial, antiviral, cardiovascular-protective, antiulcer, and many other useful pharmacological activities. In accordance with our consolidated experience gained over the years in the chemistry and biology of tricyclic pyridazin-3(2H)ones, this review summarizes SAR studies of such pyridazinone-based polycyclic compounds endowed with various biological and therapeutic properties.

Understanding therapeutic tolerance through a mathematical model of drug-induced resistance

There is growing recognition that phenotypic plasticity enables cancer cells to adapt to various environmental conditions. An example of this adaptability is the ability of an initially sensitive population of cancer cells to acquire resistance and persist in the presence of therapeutic agents. Understanding the implications of this drug-induced resistance is essential for predicting transient and long-term tumor dynamics subject to treatment. This paper introduces a mathematical model of drug-induced resistance which provides excellent fits to time-resolved in vitro experimental data. From observational data of total numbers of cells, the model unravels the relative proportions of sensitive and resistance subpopulations and quantifies their dynamics as a function of drug dose. The predictions are then validated using data on drug doses that were not used when fitting parameters. Optimal control techniques are then utilized to discover dosing strategies that could lead to better outcomes as quantified by lower total cell volume.

Osteoimmunology: Crosstalk Between T Cells and Osteoclasts in Osteoporosis

Osteoporosis, a common metabolic condition that affects the bones, increases the risk of fractures, thereby diminishing one's quality of life and, in severe cases, can even result in life-threatening conditions. Osteoporosis is becoming increasingly prevalent worldwide as the population ages. Previous research on osteoporosis has focused on skeletal cellular components such as osteoblasts and osteoclasts. The emerging field of "osteoimmunology" has recently been introduced through new research. The concept highlights the critical impact of bone-immune system interactions on osteoporosis progression. The pathogenesis of osteoporosis is significantly influenced by T cells, particularly cytotoxic and helper T cells, which modulate osteoclast differentiation and activity. A crucial aspect of understanding osteoporosis is how T lymphocytes interact with osteoclasts. However, the precise mechanisms underlying T cell-osteoclast crosstalk remain poorly understood. This review systematically examines T cell and osteoclast involvement in osteoimmunology, with a particular focus on their involvement in osteoporosis. It seeks to elucidate the immune mechanisms driving the progression of osteoporosis and identify key molecules involved in T cell-osteoclast interactions. This aims to discover novel molecular targets and intervention strategies to improve early diagnosis and management of osteoporosis. Furthermore, this article will explore the potential of intervening in T cell-osteoclast interactions using conventional therapies, traditional Chinese medicine, immunomodulatory agents, and nanomaterial-based treatments, providing new perspectives for future osteoporosis management.

Natural and Designed Cyclic Peptides as Potential Antiviral Drugs to Combat Future Coronavirus Outbreaks

The COVID-19 pandemic has underscored the need for effective and affordable antiviral drugs. Anthropogenic activities have increased interactions among humans, animals, and wildlife, contributing to the emergence of new and re-emerging viral diseases. RNA viruses pose significant challenges due to their rapid mutation rates, high transmissibility, and ability to adapt to host immune responses and antiviral treatments. The World Health Organization has identified several diseases (COVID-19, Ebola, Marburg, Zika, and others), all caused by RNA viruses, designated as being of priority concern as potential causes of future pandemics. Despite advances in antiviral treatments, many viruses lack specific therapeutic options, and more importantly, there is a paucity of broad-spectrum antiviral drugs. Additionally, the high costs of current treatments such as Remdesivir and Paxlovid highlight the need for more affordable antiviral drugs. Cyclic peptides from natural sources or designed through molecular modeling have shown promise as antiviral drugs with stability, low toxicity, high target specificity, and low antiviral resistance properties. This review emphasizes the urgent need to develop specific and broad-spectrum antiviral drugs and highlights cyclic peptides as a sustainable solution to combat future pandemics. Further research into these compounds could provide a new weapon to combat RNA viruses and address the gaps in current antiviral drug development.

Point-of-care nucleic acid testing - a step forward in controlling the HIV epidemic: A review

INTRODUCTION

The HIV/AIDS epidemic, with 85.6 million infections and 40.4 million AIDS-related deaths globally, remains a critical public health challenge. Current diagnostic methods, primarily fourth-generation immunoassays, have limitations due to their long window periods, and most viral load assays require centralized testing protocols that result in delays, especially in remote regions.

NUCLEIC ACID TESTING

Point-of-care (POC) nucleic acid amplification testing (NAAT) presents a transformative approach by reducing the window period for detection to one week and significantly shortening turnaround times for viral load monitoring.

DISCUSSION

This review highlights the clinical utility of POC NAAT for acute HIV infection diagnosis, its role in timely combination antiretroviral therapy adjustments, and its potential to reduce the basic reproduction number (R0), a critical threshold for suppressing the epidemic.

CONCLUSION

By improving early detection and facilitating faster clinical decisions, POC NAAT enhances the effectiveness of HIV prevention and treatment programmes, particularly in high-risk and remote communities, and supports the global effort to achieve the ambitious UNAIDS 95-95-95 targets.

Comparison of HIV-1 RNA and HIV-1 DNA Genotypic Drug Resistance Testing in Women of Childbearing Age Infected with HIV-1 in Liangshan Prefecture

This study focuses on women of childbearing age infected with HIV-1 in Liangshan Prefecture and analyses their HIV-1 RNA and HIV-1 DNA genotypic drug resistance to provide a theoretical basis and technical support for monitoring the spread of resistant strains and formulating and optimizing antiretroviral therapy regimens. The study subjects were women of childbearing age infected with HIV-1 who were followed up in the county of Liangshan Prefecture from January to September 2023. Peripheral venous blood samples were collected from each subject. The samples were centrifuged to separate the plasma and blood cells for HIV-1 RNA quantitative testing and HIV-1 genotypic drug resistance testing. A total of 47 participants were included in this study. When HIV-1 RNA were <50 copies/mL and between 50 and 1,000 copies/mL, the success rate of HIV-1 DNA pol gene amplification was significantly higher than that of HIV-1 RNA pol gene amplification. Among the 47 subjects, 17 (17/47, 36.17%) indicated successfully amplified HIV-1 RNA and HIV-1 DNA genotypic drug resistance in each region simultaneously, and 9 (9/17, 52.94%) developed any degree of resistance. Among these nine cases, five had consistent resistance, while four indicated inconsistent resistance. Among the five cases with identical drug resistance, there were three cases with inconsistent drug resistance mutations (DRMs). Among the four cases with inconsistent drug resistance results, one had DRMs at the HIV-1 DNA level but no DRMs at the HIV-1 RNA level, while the other three had more DRMs at the HIV-1 RNA level than at the HIV-1 DNA level. The combination of HIV-1 RNA and HIV-1 DNA genotypic drug resistance testing can improve the drawbacks of current single HIV-1 RNA genotypic drug resistance testing, especially when HIV-1 RNA is ≤1,000 copies/mL, and significantly improve the efficiency of HIV-1 genotypic drug resistance testing.

Induction of hepatitis B core protein aggregation targeting an unconventional binding site

The hepatitis B virus (HBV) infection is a major global health problem, with chronic infection leading to liver complications and high death toll. Current treatments, such as nucleos(t)ide analogs and interferon-α, effectively suppress viral replication but rarely cure the infection. To address this, new antivirals targeting different components of the HBV molecular machinery are being developed. Here we investigated the hepatitis B core protein (HBc) that forms the viral capsids and plays a vital role in the HBV life cycle. We explored two distinct binding pockets on the HBV capsid: the central hydrophobic pocket of HBc-dimers and the pocket at the tips of capsid spikes. We synthesized a geranyl dimer that binds to the central pocket with micromolar affinity, and dimeric peptides that bind the spike-tip pocket with sub-micromolar affinity. Cryo-electron microscopy further confirmed the binding of peptide dimers to the capsid spike tips and their capsid-aggregating properties. Finally, we show that the peptide dimers induce HBc aggregation in vitro and in living cells. Our findings highlight two tractable sites within the HBV capsid and provide an alternative strategy to affect HBV capsids.

Pathogenesis and clinical management of arboviral diseases

Arboviral diseases are viral infections transmitted to humans through the bites of arthropods, such as mosquitoes, often causing a variety of pathologies associated with high levels of morbidity and mortality. Over the past decades, these infections have proven to be a significant challenge to health systems worldwide, particularly following the considerable geographic expansion of the dengue virus (DENV) and its most recent outbreak in Latin America as well as the difficult-to-control outbreaks of yellow fever virus (YFV), chikungunya virus (CHIKV), and Zika virus (ZIKV), leaving behind a substantial portion of the population with complications related to these infections. Currently, the world is experiencing a period of intense globalization, which, combined with global warming, directly contributes to wider dissemination of arbovirus vectors across the globe. Consequently, all continents remain on high alert for potential new outbreaks. Thus, this review aims to provide a comprehensive understanding of the pathogenesis of the four main arboviruses today (DENV, ZIKV, YFV, and CHIKV) discussing their viral characteristics, immune responses, and mechanisms of viral evasion, as well as important clinical aspects for patient management. This includes associated symptoms, laboratory tests, treatments, existing or developing vaccines and the main associated complications, thus integrating a broad historical, scientific and clinical approach.

PLGA-Encapsulated Elvitegravir and Curcumin Modulates ART Penetration, Oxidative Stress, and Inflammation

Background/Objectives: HIV persists in central nervous system (CNS) reservoirs, where infected microglia and macrophages drive neuroinflammation, oxidative stress, and neuronal damage, contributing to HIV-associated neurocognitive disorder (HAND). Nanoparticle-based drug delivery systems, particularly poly(lactic-co-glycolic acid) (PLGA) nanoparticles, offer a promising strategy to improve CNS antiretroviral therapy (ART) delivery. This study aimed to evaluate the efficacy of co-administration of PLGA nanoparticles (NPs) encapsulating elvitegravir (EVG) and curcumin (CUR) in targeting CNS reservoirs, reducing neuroinflammation, and mitigating oxidative stress. Methods: PLGA NPs encapsulating EVG and CUR (PLGA-EVG and PLGA-CUR) were prepared via the nanoprecipitation method. The NPs were characterized for size, zeta potential, and encapsulation efficiency (EE). Their therapeutic efficacy was evaluated in vitro using U1 macrophages and in vivo in Balb/c mice. Key parameters, including cytokine levels, oxidative stress markers, and neuronal marker expression, were analyzed. Results: The PLGA-EVG and PLGA-CUR NPs demonstrated high EE% (~90.63 ± 4.21 for EVG and 87.59 ± 3.42 for CUR) and sizes under 140 nm, ensuring blood-brain barrier (BBB) permeability. In vitro studies showed enhanced intracellular EVG concentrations and reductions in proinflammatory cytokines (IL-1β, TNFα, and IL-18) and improved antioxidant capacity in U1 macrophages. In vivo, the co-administration of NPs improved CNS drug delivery, reduced neuroinflammation and oxidative stress, and preserved neuronal markers (L1CAM, synaptophysin, NeuN, GFAP). Conclusions: PLGA-based co-delivery of EVG and CUR enhances ART CNS drug delivery, mitigating neuroinflammation and reducing oxidative stress. These findings highlight the potential of nanoparticle-based ART strategies to address limitations in current regimens and pave the way for more effective HAND therapies. Future studies should focus on optimizing formulations and evaluating safety in chronic HIV settings.

In Vitro Transcribed Artificial Primary MicroRNA for the Inhibition of Hepatitis B Virus Gene Expression in Cultured Cells

Available interventions for the management of chronic hepatitis B (hepB) exhibit limited efficacy and barriers to vaccination against the hepatitis B virus (HBV) have hampered prophylaxis programmes. Development of potent therapeutics capable of functional cure of chronic hepB thus remains a relevant medical objective. RNA interference (RNAi) can be exploited to effect potent and specific silencing of target genes through the introduction of RNA sequences that mimic the natural activators of the pathway. To achieve a therapeutic effect, artificial primary microRNAs (pri-miRNAs) have been used extensively to target various viruses, including HBV. To date artificial pri-miRNAs have exclusively been produced from DNA expression cassettes. Although this achieves impressive silencing, eventual translation of this platform to the clinic is complicated by the requirement for viral vectors to deliver DNA. Consequently, clinical translation has been slow. Recently, the use of in vitro transcribed RNA, specifically to produce mRNA vaccines at industrial scale, has gained significant interest. We therefore sought to evaluate the feasibility of using in vitro transcribed artificial pri-miRNAs for the inhibition of HBV gene expression. Artificial HBV-targeting pri-miR-31 sequences, which are highly effective when expressed in cells from a DNA template, demonstrated modest silencing of viral replication when incorporated into mRNA that was transcribed in vitro. Off-target effects were also observed. Characterisation revealed that intracellular processing of the artificial pri-miRNAs was inefficient and non-specific effects were caused by stimulation of the interferon response. Nevertheless, optimised nuclear delivery of the artificial pri-miRNAs should improve their processing and achieve better anti-hepB efficacy.

Development and characterization of a double-fluorescent HIV-1 reporter cellular model to tackle the Rev-dependent export pathway

The Rev-dependent nuclear export of unspliced and singly-spliced transcripts of human immunodeficiency virus type 1 (HIV-1) constitutes a critical yet poorly characterized post-transcriptional event essential for effective viral replication. In this study, we engineered a dual-fluorescent HIV-1-based cellular reporter system to elucidate the mechanisms underpinning Rev-dependent export. By generating multiple stably integrated inducible cellular clones, we ensured the expression of two distinct fluorescent proteins, mKO2, and ECFP, from unspliced (Rev dependent) and multiply spliced (Rev independent) HIV-1 transcripts, respectively. Utilizing flow cytometry, we performed quantitative analyses of dual-fluorescent cell populations. The developed tool enables precise assessment of the Rev-dependent export, and we validated it using known inhibitors of this pathway (leptomycin D), as well as targeted depletion of MATR3, an essential cofactor of Rev, and CRNKL1, a repressor of unspliced HIV-1 RNA export.IMPORTANCEThe developed dual-fluorescent reporter system represents a powerful and handy tool for the identification and characterization of novel molecular players involved in the Rev-dependent export pathway. This system not only holds promise for advancing our understanding of human immunodeficiency virus type 1 (HIV-1) biology but also serves as an invaluable platform for high-throughput drug screening aimed at targeting post-transcriptional HIV-1 RNA processes, particularly nuclear export. Consequently, this study offers significant implications for the development of novel therapeutic strategies to eradicate the virus.

Potential therapeutics and vaccines: Current progress and challenges in developing antiviral treatments or vaccines for Oropouche virus

Oropouche virus (OROV), an emerging arbovirus, poses a significant public health challenge in tropical and subtropical regions, with no licensed vaccines or antiviral therapies currently available. This review explores recent advancements in therapeutic strategies and vaccine development for OROV, focusing on molecular mechanisms of viral replication, identification of potential antiviral targets, and the role of immunotherapy in managing infections. Promising antiviral candidates, including ribavirin, mycophenolic acid, and interferon, have demonstrated efficacy in in vitro studies, offering a foundation for further investigation. The challenges of preclinical and clinical development, such as high mutation rates, immune response variability, and vaccine delivery hurdles, are critically analyzed. By addressing the progress and remaining gaps, this article aims to provide a comprehensive overview to inform future research and facilitate the development of effective antiviral strategies and vaccines for OROV.

Deciphering the enigmas of non-nucleoside reverse transcriptase inhibitors (NNRTIs): A medicinal chemistry expedition towards combating HIV drug resistance

The pivotal involvement of reverse transcriptase activity in the pathogenesis of the progressive HIV virus has stimulated gradual advancements in drug discovery initiatives spanning three decades. Consequently, nonnucleoside reverse transcriptase inhibitors (NNRTIs) have emerged as a preeminent category of therapeutic agents for HIV management. Academic institutions and pharmaceutical companies have developed numerous NNRTIs, an essential component of antiretroviral therapy. Six NNRTIs have received Food and Drug Administration approval and are widely used in clinical practice, significantly improving the quality of HIV patients. However, the rapid emergence of drug resistance has limited the effectiveness of these medications, underscoring the necessity for perpetual research and development of novel therapeutic alternatives. To supplement the existing literatures on NNRTIs, a comprehensive review has been compiled to synthesize this extensive dataset into a comprehensible format for the medicinal chemistry community. In this review, a thorough investigation and meticulous analysis were conducted on the progressions achieved in NNRTIs within the past 8 years (2016-2023), and the experiences and insights gained in the development of inhibitors with varying chemical structures were also summarized. The provision of a crucial point of reference for the development of wide-ranging anti-HIV medications is anticipated.

Changes in the lipid profile in people with HIV after one year of antiretroviral therapy - the significance of immune parameters

Objectives

This study aimed to analyze lipid profiles among people with HIV and observe changes in lipid parameters during 1 year of antiretroviral therapy (ART), with particular reference to immune parameters.

Methods

We analyzed adult newly diagnosed people with HIV (PWH) who started ART, continued uninterruptedly for 1 year and achieved complete viral suppression. Patients were not receiving lipid-lowering therapy. The cluster of differentiation (CD4) count, CD4:CD8 ratio, HIV type 1 viral load, and lipid profile were examined at HIV diagnosis and after 12 months of ART.

Results

The study included 70 patients. Significant increases in total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol and decreases in triglyceride concentrations after 1 year of ART were observed. A baseline CD4 count <200/µl was associated with higher baseline LDL cholesterol (P = 0.036), and female sex with elevated total, LDL, and non-HDL cholesterol (P = 0.005; P = 0.011; P = 0.008). Patients with baseline CD4 counts <200/µl had significantly higher total, LDL, and non-HDL cholesterol (P = 0.033; P = 0.009; P = 0.009) and triglyceride (P = 0.003) levels after 1 year of ART than patients with CD4 levels ≥200/µl.

Conclusions

Lipid parameters should be regularly assessed in all PWH receiving ART, especially in patients with baseline CD4 counts <200/µl.

Preclinical testing of antiviral siRNA therapeutics delivered in lipid nanoparticles in animal models - a comprehensive review

The advent of RNA interference (RNAi) technology through the use of short-interfering RNAs (siRNAs) represents a paradigm shift in the fight against viral infections. siRNAs, with their ability to directly target and silence specific posttranscriptional genes, offer a novel mechanism of action distinct from that of traditional pharmacotherapeutics. This review delves into the growing field of siRNA therapeutics against viral infections, highlighting their critical role in contemporary antiviral strategies. Importantly, this review will solely focus on the use of lipid nanoparticles (LNPs) as the ideal antiviral siRNA delivery agent for use in vivo. We discuss the challenges of siRNA delivery and how LNPs have emerged as a pivotal solution to enhance antiviral efficacy. Specifically, this review focuses on work that have preclinically tested LNP formulated siRNA on virus infection animal models. Since the COVID-19 pandemic, we have witnessed a resurgence in the field of RNA-based therapies, including siRNAs against viruses including, SARS-CoV-2. Notably, the critical importance of LNPs as the ideal carrier for precious 'RNA cargo' can no longer be ignored with the advent of mRNA-LNP based COVID-19 vaccines. siRNA-based therapeutics represents an emerging class of anti-infective drugs with a foreseeable future as suitable antiviral agents.

Challenges for Novel Antiretroviral Development in an Era of Widespread tenofovir-disoproxil/lamivudine (or emtricitabine)/dolutegravir availability (TLD) Availability

More than 80% of people with human immunodeficiency virus (HIV) in low- and middle-income countries (LMICs) take first-line tenofovir-disoproxil/lamivudine (or emtricitabine)/dolutegravir (TLD). Due to hard-fought activism, TLD now costs <$45 per person per year in more than 100 LMICs under Voluntary License. With final dolutegravir (DTG) patents expiring by 2029, generic TLD will soon be available globally. Here, we identify seven critical benchmarks that underpin TLDs' success which novel antiretroviral therapy (ART) should now meet, and an eighth benchmark for which novel ART should aim. These benchmarks are superior efficacy; high genetic barrier to resistance; safety in hepatitis B coinfection; favourable drug interaction profiles; HIV2 efficacy; safety in pregnancy, long-acting formulation availability and affordable pricing. We compare the generic TLD availability timeline with development timelines for two case-study novel ART combinations: islatravir/doravirine and cabotegravir/rilpivirine. We demonstrate that currently these regimens and trial programs will not meet key benchmarks required to compete with TLD.

Cannabis Use in HIV: Impact on Inflammation, Immunity and the Microbiome

PURPOSE OF REVIEW

This review explores how cannabis impacts the gut microbiome, immune system, and ART outcomes in people with HIV (PWH). Given the increasing prevalence of cannabis use among PWH, we investigated its potential to reduce chronic inflammation and enhance gut health, both of which can influence HIV pathogenesis.

RECENT FINDINGS

Cannabis has immunomodulatory and anti-inflammatory effects, including reducing systemic inflammatory biomarkers (such as MCP-1 and IP-10) and improving gut barrier integrity through increased short-chain fatty acid (SCFA) production. Studies have shown that cannabis use is associated with increased gut mucosal immunity, decreased immune activation, and a unique microbiome composition. Preliminary evidence indicates that cannabis may influence HIV reservoirs, although the results remain inconclusive. Cannabis shows promise in managing inflammation, gut dysbiosis, and immune dysfunction in PWH. However, its effects on HIV reservoirs, adherence to antiretroviral therapy, and long-term outcomes need further investigation through rigorous clinical trials using standardized formulations.

Enhancing thermostability of Moloney murine leukemia virus reverse transcriptase through greedy combination of multiple mutant residues

Reverse transcription is crucial in bioengineering and biomedical fields, particularly for genome sequencing and virus diagnosis. Enhancing the thermostability of reverse transcriptase can significantly improve its efficiency and accuracy by enabling it to function at higher temperatures, thereby reducing RNA secondary structures and minimizing interference from contaminating enzymes, particularly in clinical samples. Here, using a combinatorial strategy, a variant of Moloney Murine Leukemia Virus reverse transcriptase (MMLV RT) with improved activity across a wide temperature range (30-50 °C) was identified and maintained 100% activity after incubation at 50 °C for 10 min. Eleven hot-spot residues were mutated in various combinations, and the mutant proteins were rapidly expressed in a cell-free system for reverse transcription activity testing. Variant M5, which carries five mutated residues (E47K/E280R/T284R/L413G/D631V), exhibited enhanced thermostability and activity compared to any variant with a single residue mutation. Using purified recombinant protein for precise characterization, the melting temperature (Tm) of M5 increased by 4.7 °C when assembled with a nucleotide template-primer (T/P). Consequently, the half-life of M5 at 50 °C extended to approximately 60 min, in contrast to less than 4 min for the wild type. These findings demonstrate that the epistasis of combining multiple mutant residues holds excellent potential for significantly enhancing enzyme activity, even with existing knowledge. This heat-stable MMLV RT variant M5 may potentially improve efficiency and accuracy in molecular biology research and clinical diagnostics.

Quality assessment strategy development and analytical method selection of GMP grade biological drugs for gene and cell therapy

Biological drugs with gene and cell therapy potentials, including natural or rationally created biomacromolecules, recombinant proteins/enzymes, gene-carrying DNA/RNA fragments, oncolytic viruses, plasmid and viral vectors or other gene delivering vehicles with specific therapeutic genes and gene manipulation tools, and genetically modified and reprogrammed human cells comprise a large fraction of drug development candidates in modern precision and regeneration medicine. These drugs have displayed unique capabilities in treating patients with previously incurable diseases. However, most of the drug preparations have complex multimolecular structures and require specific biomanufacturing systems and many other additional biological active materials for drug synthesis, cell expansion, and production enhancement. Thus, the final products would have to be subjected to sequential extensive purification processes to exclude impurities and to concentrate the drug products after manufacturing. The quality evaluation for each drug product is an individualized process and must be specifically designed and performed according to the characteristics of the drug and its manufacturing and purification methods. Some of the Quality Control (QC) assays may be very costly and time-consuming, frequently with inconsistent test results from batch-to-batch. This review focuses on QC assessment strategy development for common gene and cell therapy drugs which use prokaryotic or eukaryotic cells for manufacturing or cell factories for in vitro expansions, especially for drug identification and concentration determination, impurity detection and quantification, drug potency, stability, and safety evaluations; and discusses some key issues for drug quality assessments in different categories and emphasizes the importance of individualized QC strategy design.

Playing Around the Coumarin Core in the Discovery of Multimodal Compounds Directed at Alzheimer's-Related Targets: A Recent Literature Overview

Alzheimer's disease (AD) causes a great socioeconomic burden because of its increasing prevalence and the lack of effective therapies. The multifactorial nature of AD prompts researchers to search for new strategies for discovering disease-modifying therapeutics. To this extent, the multitarget approach holds the potential of synergic or cooperative activities arising from compounds that are properly designed to address two or more pathogenetic mechanisms. As a privileged and nature-friendly scaffold, coumarin has successfully been enrolled as the heterocyclic core in the design of multipotent anti-Alzheimer's agents. Herein, we comprehensively summarize the most recent literature (2018-2023), covering the rational design and the discovery of coumarin-containing multitarget directed ligands (MTDLs) whose anti-AD profile encompassed at least two different biological activities relevant for disease onset and progression. To enhance the clarity of presentation, synthetic coumarin-based MTDLs are categorized into four clusters based on their substitution pattern and reported bioactivities: (i) mono-, (ii) di-, and (iii) polysubstituted coumarins directed at protein targets, and (iv) coumarins directed at protein targets with additional metal-chelating features. Before discussing multimodal coumarins, the rationale for addressing each biological target is briefly presented.

Predicting antiretroviral medication adherence among substance-using people with HIV: test and extension of the information-motivation-behavioral skills model

Antiretroviral therapy (ART) is effective in reducing HIV transmission and mortality, yet daily adherence remains a challenge for many people with HIV (PWH). Suboptimal adherence can lead to virological failure and increased mortality, particularly among those with substance use disorders, such as cocaine use disorder (CUD). The Information-Motivation-Behavioral (IMB) skills model offers a framework to understand and enhance ART adherence by addressing individual and social barriers. In this study, we tested the IMB skills model among 80 cocaine-using PWH currently on ART, and found that behavioral skills significantly predicted adherence. In the extension of the IMB skills model, the addition of practical barriers altered the relationship by showing that motivational barriers such as treatment fatigue and practical barriers significantly affected ART adherence. The findings suggest that for PWH with substance use disorders, addressing practical barriers and motivational factors may be crucial for improving ART adherence, in addition to building behavioral skills.

A tale of two drugs: Molnupiravir and Paxlovid

The orally administered antiviral drug Lagevrio or molnupiravir (MOV) and the combination antiviral drug nirmatrelvir/ritonavir or Paxlovid (PAX) have been shown to reduce the likelihood of hospitalization and death for high-risk patients with COVID-19. Clinical studies, including those comparing PAX and MOV, were reviewed; both drugs are effective in reducing morbidity and mortality in COVID patients, although PAX generally appears to be more efficacious. Both drugs received Emergency Use Authorization in the United States for mild to moderate COVID-19 infection, while only PAX has subsequently been given full FDA approval. The principal disadvantage of PAX is that it interacts with many commonly used drugs, while MOV does not. The purpose of this review is to summarize current information and knowledge about these two drugs. The two drugs have completely different mechanisms of action. PAX inhibits viral replication while MOV induces viral replication errors that are expected to lead to viral inactivation. There is, however, the potential that MOV also could mutate host DNA and cause the virus to mutate into variants with new features. The package insert for MOV states that patients should be notified of relevant toxicity issues before administration. Sensitive mutation detection/analysis studies, such as error corrected Next Generation Sequencing (ecNGS) or HPRT mutation detection assays, in MOV-treated patients are needed to establish the safety of MOV.

Engineering a live-attenuated porcine reproductive and respiratory syndrome virus vaccine to prevent RNA recombination by rewiring transcriptional regulatory sequences

Recombination is a significant factor driving the evolution of RNA viruses. The prevalence and variation of porcine reproductive and respiratory syndrome virus (PRRSV) in China have been increasing in complexity due to extensive interlineage recombination. When this recombination phenomenon occurs in live vaccine strains, it becomes increasingly difficult to prevent and control PRRSV. Reverse genetic manipulation to engineer a different transcriptional regulatory sequence (TRS) circuit introduces genetic traps into the viral genome that are lethal to recombinant RNA progeny viruses. In this study, major interlineage recombination patterns were identified between lineage 1 (L1) PRRSVs and lineage 8 (L8) PRRSVs in China, from 2019 to 2023. The recombinant mutant virus, vA-TRSall, was constructed and successfully rescued by rewiring the entire TRS circuit without changing the amino acid-coding sequence in the genome of the PRRSV live vaccine strain vHuN4-F112. The vA-TRSall, with a brand new TRS circuit, provided effective immune protection against the highly pathogenic L8 PRRSV (vHuN4) and epidemic NADC30-like L1 PRRSV (vZJqz21). Recombination analysis in vitro and in vivo showed that, compared with the vHuN4-F112 and vZJqz21 co-infection groups, the incidence rates of mutation breakpoints and template-switching recombination in the vA-TRSall and vZJqz21 co-infected groups were effectively reduced. The results have enriched our understanding of the critical role of TRS circuits in PRRSV recombination mechanisms and indicate a successful redesign that can endow PRRSV live vaccines with recombination-resistant capabilities.

IMPORTANCE

Porcine reproductive and respiratory syndrome viruses (PRRSVs) are genetically diverse, and this is due in part to their extensive recombination. Live vaccines are widely used to prevent and control PRRS in China. However, owing to the wide variety of live vaccines, non-standard use, and the wild viruses prevalent on pig farms, new strains, generated via RNA recombination, are continuously emerging. Vaccine strains are also involved in PRRSV recombination, which leads to the emergence of new variants and alterations in virulence and pathogenesis. A recombination-resistant genome was engineered by rewiring the entire transcriptional regulatory sequence (TRS) circuit of the live PRRSV vaccine strain. Theoretically, after clinical application, once the virus recombines with the genome of the epidemic strain, the base pairing between the two sets of TRS circuits should be disrupted, resulting in a fatal genetic trap for the generation of an RNA recombinant progeny virus. Therefore, the remodeled PRRSV TRS mutant generated in this study can serve as a recombination-resistant platform for the rational design of safe PRRS vaccines in the future.

Clinical events associated with poor CD4+ T-cell recovery in people living with HIV following ART: A systematic review and meta-analysis

BACKGROUND

Antiretroviral therapy (ART) has significantly improved outcomes for people living with HIV (PLWH), but poor CD4+ T-cell recovery remains a challenge. This study aimed to evaluate the relationship between poor CD4+ T-cell recovery and the morbidity of clinical events (CEs) in PLWH after ART initiation.

METHODS

We conducted a comprehensive search of the EMBASE, PubMed, Web of Science, and Cochrane Library databases up to February 19, 2024, and included studies that reported the number of CEs along with the CD4 count at the time of the CEs or the most recent CD4 count prior to the CEs. A random-effects model was employed for meta-analysis to calculate odds ratios (ORs) and their 95% confidence intervals (CIs) for CEs at different CD4 count thresholds.

FINDINGS

We included 15 studies with 54,766 PLWH and reported a significant inverse correlation between CD4+ T-cell counts and the morbidity of both AIDS-defining events (ADEs) and non-AIDS-defining infections (NADIs). However, CD4+ T-cell counts were not significantly associated with non-AIDS-defining noninfections (NADNIs). Compared with individuals with normal CD4 counts (>500 cells/μL), those with CD4 counts <200 cells/μL and 200-350 cells/μL exhibited higher ADEs morbidity, with ORs of 7·04 (95% CI: 1·77-28·03) and 1·63 (95% CI: 1·36-1·97), respectively. Similarly, individuals with CD4 counts <200 cells/μL showed a higher morbidity of NADIs (OR = 2·82, 95% CI: 1·50-5·31). However, no significant difference in NADNI morbidity was observed between groups with poor CD4+ T-cell recovery and those with normal CD4 counts.

INTERPRETATION

This meta-analysis revealed an inverse relationship between CD4+ T-cell counts and morbidity associated with ADEs and NADIs in PLWH after ART initiation, with key thresholds of 350 cells/μL and 200 cells/μL. No significant associations were found between CD4 counts and NADNIs. These results highlight the need for comprehensive patient care that goes beyond monitoring only CD4 counts.

Deciphering the Molecular Mechanisms of HAART-Induced Hepatotoxicity

Highly active antiretroviral therapy (HAART), consisting of three or more antiretroviral drugs, is recommended for patients with HIV infection. HAART effectively reduces HIV RNA levels, lowers the risk of opportunistic infections, and improves immune function and survival rates. However, it is also associated with an increased risk of liver injury in HIV-infected individuals. This review aims to summarize the mechanisms underlying HAART-induced liver injury. A comprehensive search was conducted in PubMed and EMBASE using keywords such as "Antiretroviral/ARV drugs and drug-induced liver injury (DILI)," "HAART and DILI," "Antiretroviral therapy and DILI," and "HIV infection and DILI." Relevant papers published before March 2024 were included. Experimental studies have demonstrated that zidovudine and efavirenz can cause structural alterations in mitochondria, impair the respiratory chain, generate free radicals, and deplete mitochondrial DNA, leading to oxidative and endoplasmic reticulum stress, as well as the accumulation of advanced glycation end products in liver tissue. Zidovudine disrupts lipid homeostasis by increasing fatty acid synthesis and reducing metabolism. Efavirenz and its metabolite, 8-hydroxyefavirenz, induce hepatocellular death and activate proapoptotic markers through c-Jun N-terminal kinase signaling. Additionally, lamivudine has been shown to induce liver injury and oxidative stress in rats. Clinically, approximately 50% of HIV patients on HAART regimens containing non-nucleoside reverse transcriptase inhibitors experience mild to moderate liver injury. HAART regimens that include efavirenz, lamivudine, and tenofovir impair glucose and lipid homeostasis in rats, highlighting the need for caution in HIV patients with fatty liver disease. Patients with viral hepatitis coinfection, those taking antitubercular drugs or cotrimoxazole, and those on nevirapine-containing regimens are at particularly high risk. Regular monitoring of liver function is essential to prevent liver damage associated with HAART in HIV-infected patients. While HAART significantly improves survival rates in HIV patients, it also poses a considerable risk of liver injury, necessitating careful monitoring and management.

Chronic Hepatitis B Virus Persistence: Mechanisms and Insights

Chronic hepatitis B (CHB) virus infection can lead to severe liver diseases, including cirrhosis and hepatocellular carcinoma. The chronicity of the hepatitis B virus (HBV) occurs because of the persistence of viral covalently closed circular DNA (cccDNA) within hepatocytes. The cccDNA serves as the template for viral replication and is central to HBV, maintaining a viral reservoir within the host. Despite therapeutic advancements, eliminating cccDNA remains elusive due to its evasion of immune surveillance. This review explores the formation and maintenance of cccDNA, highlighting host factors influencing cccDNA stability and viral replication. It also discusses current treatment strategies, including interferon-based therapies and nucleoside/nucleotide analogs, which aim to suppress viral replication. Emerging therapies such as gene editing and molecular interventions hold promise for targeting cccDNA directly. Currently, research is focused on making medications that target host factors of interest to disrupt or clear the viral reservoir. However, future research should focus on innovative approaches that directly target the cccDNA minichromosome, aiming for sustained viral suppression and potentially a cure for the HBV infection.

Hepatitis B core-related antigen as a promising serological marker for monitoring hepatitis B virus cure

Hepatitis B virus (HBV) infection is a global health concern. The current sequential endpoints for the treatment of HBV infection include viral suppression, hepatitis B e antigen (HBeAg) seroconversion, functional cure, and covalently closed circular DNA (cccDNA) clearance. Serum hepatitis B core-related antigen (HBcrAg) is an emerging HBV marker comprising three components: HBeAg, hepatitis B core antigen, and p22cr. It responds well to the transcriptional activity of cccDNA in the patient's liver and is a promising alternative marker for serological testing. There is a strong correlation, and a decrease in its level corresponds to sustained viral suppression. In patients with chronic hepatitis B (CHB), serum HBcrAg levels are good predictors of HBeAg seroconversion (both spontaneous and after antiviral therapy), particularly in HBeAg-positive patients. Both low baseline HBcrAg levels and decreasing levels early in antiviral therapy favored HBsAg seroconversion, which may serve as a good surrogate option for treatment endpoints. In this review, we summarize the role of serum HBcrAg in the treatment of CHB. Therefore, long-term continuous monitoring of serum HBcrAg levels contributes to the clinical management of patients with CHB and optimizes the choice of treatment regimen, making it a promising marker for monitoring HBV cure.

Next-Generation Sequencing Methods to Determine the Accuracy of Retroviral Reverse Transcriptases: Advantages and Limitations

Retroviruses, like other RNA viruses, mutate at very high rates and exist as genetically heterogeneous populations. The error-prone activity of viral reverse transcriptase (RT) is largely responsible for the observed variability, most notably in HIV-1. In addition, RTs are widely used in biotechnology to detect RNAs and to clone expressed genes, among many other applications. The fidelity of retroviral RTs has been traditionally analyzed using enzymatic (gel-based) or reporter-based assays. However, these methods are laborious and have important limitations. The development of next-generation sequencing (NGS) technologies opened the possibility of obtaining reverse transcription error rates from a large number of sequences, although appropriate protocols had to be developed. In this review, we summarize the developments in this field that allowed the determination of RNA-dependent DNA synthesis error rates for different RTs (viral and non-viral), including methods such as PRIMER IDs, REP-SEQ, ARC-SEQ, CIR-SEQ, SMRT-SEQ and ROLL-SEQ. Their advantages and limitations are discussed. Complementary DNA (cDNA) synthesis error rates obtained in different studies, using RTs and RNAs of diverse origins, are presented and compared. Future improvements in methodological pipelines will be needed for the precise identification of mutations in the RNA template, including modified bases.

Identification of HIV-1 Reverse Transcriptase-Associated Ribonuclease H Inhibitors Based on 2-Hydroxy-1,4-naphthoquinone Mannich Bases

There is a strong demand for new and efficient antiviral compounds. A series of 2-hydroxy-1,4-naphthoquinone Mannich bases were screened for their HIV-1-RNase H inhibitory activity. An HIV-1-RNase H assay was used to study the RNase H inhibition by the test compounds. Docking of active derivatives into the active site of the enzyme was carried out. Compounds 1e and 2k showed distinctly higher HIV-1-RNase H inhibitory activity (IC50 = 2.8-3.1 µM) than the known inhibitors RDS1759 and compound 13. The binding mode and possible interactions of 1e and 2k with the HIV-1-RNase H active site were determined using molecular docking, which led to the identification of salient and concealed pharmacophoric features of these molecules. The docking analysis revealed that there are significant differences in the binding mode of these compounds within the active site of the target enzyme. A selection of HIV-1-RNase H-inhibitory Mannich bases was tested for antiviral activity against HIV-1, and compound 2k showed the highest activity at low toxicity to host cells. The lawsone Mannich bases 1e and 2k also underwent a preliminary screening for activity against SARS-CoV-2, and compound 1e was found to inhibit SARS-CoV-2 replication (IC50 = 11.2 µM).

Harnessing antiviral RNAi therapeutics for pandemic viruses: SARS-CoV-2 and HIV

Using the knowledge from decades of research into RNA-based therapies, the COVID-19 pandemic response saw the rapid design, testing and production of the first ever mRNA vaccines approved for human use in the clinic. This breakthrough has been a significant milestone for RNA therapeutics and vaccines, driving an exponential growth of research into the field. The development of novel RNA therapeutics targeting high-threat pathogens, that pose a substantial risk to global health, could transform the future of health delivery. In this review, we provide a detailed overview of the two RNA interference (RNAi) pathways and how antiviral RNAi therapies can be used to treat acute or chronic diseases caused by the pandemic viruses SARS-CoV-2 and HIV, respectively. We also provide insights into short-interfering RNA (siRNA) delivery systems, with a focus on how lipid nanoparticles can be functionalized to achieve targeted delivery to specific sites of disease. This review will provide the current developments of SARS-CoV-2 and HIV targeted siRNAs, highlighting strategies to advance the progression of antiviral siRNA along the clinical development pathway.

Systematic evaluation of intratumoral and peripheral BCR repertoires in three cancers

The current understanding of humoral immune response in cancer patients suggests that tumors may be infiltrated with diffuse B cells of extra-tumoral origin or may develop organized lymphoid structures, where somatic hypermutation and antigen-driven selection occur locally. These processes are believed to be significantly influenced by the tumor microenvironment through secretory factors and biased cell-cell interactions. To explore the manifestation of this influence, we used deep unbiased immunoglobulin profiling and systematically characterized the relationships between B cells in circulation, draining lymph nodes (draining LNs), and tumors in 14 patients with three human cancers. We demonstrated that draining LNs are differentially involved in the interaction with the tumor site, and that significant heterogeneity exists even between different parts of a single lymph node (LN). Next, we confirmed and elaborated upon previous observations regarding intratumoral immunoglobulin heterogeneity. We identified B cell receptor (BCR) clonotypes that were expanded in tumors relative to draining LNs and blood and observed that these tumor-expanded clonotypes were less hypermutated than non-expanded (ubiquitous) clonotypes. Furthermore, we observed a shift in the properties of complementarity-determining region 3 of the BCR heavy chain (CDR-H3) towards less mature and less specific BCR repertoire in tumor-infiltrating B-cells compared to circulating B-cells, which may indicate less stringent control for antibody-producing B cell development in tumor microenvironment (TME). In addition, we found repertoire-level evidence that B-cells may be selected according to their CDR-H3 physicochemical properties before they activate somatic hypermutation (SHM). Altogether, our work outlines a broad picture of the differences in the tumor BCR repertoire relative to non-tumor tissues and points to the unexpected features of the SHM process.

Recent advances in screening methods enabling the discovery of novel anti-hepatitis B virus drug candidates

The global population affected by Hepatitis B virus (HBV) is approximately 296 million, but few drugs have been able to completely eradicate HBV and the range of effective treatments remains limited. Recent advancements in molecular biology and artificial intelligence, as well as a comprehensive understanding of the molecular structure of HBV, have greatly aided the rational development of anti-HBV agents. Such advancements have facilitated an increasing array of candidate drugs transitioning into clinical trials, however, no novel target-based compounds have been approved for clinical application. To expedite the progression of anti-HBV drug development, establishing a reliable and robust in vitro HBV infection system is of great importance. However, owing to the host and tissue specificity of HBV, identifying a stable and dependable cell culture system for screening all anti-HBV agents poses significant challenges. In this review, we summarize recent advances in screening methods for small-molecule inhibitors that target key stages of the HBV replication cycle from a medicinal chemistry perspective.

Non-lytic spread of poliovirus requires the nonstructural protein 3CD

Non-enveloped viruses like poliovirus (PV) have evolved the capacity to spread by non-lytic mechanisms. For PV, this mechanism exploits the host secretory autophagy pathway. Virions are selectively incorporated into autophagosomes, double-membrane vesicles that travel to the plasma membrane, fuse, and release single-membrane vesicles containing virions. Loading of cellular cargo into autophagosomes relies on direct or indirect interactions with microtubule-associated protein 1B-light chain 3 (LC3) that are mediated by motifs referred to as LC3-interaction regions (LIRs). We have identified a PV mutant with a severe defect in non-lytic spread. An F-to-Y substitution in a putative LIR of the nonstructural protein 3CD prevented virion incorporation into LC3-positive autophagosomes and virion trafficking to the plasma membrane for release. Using high-angle annular dark-field scanning transmission electron microscopy to monitor PV-induced autophagosome biogenesis, for the first time, we show that virus-induced autophagic signals yield normal autophagosomes, even in the absence of virions. The F-to-Y derivative of PV 3CD was unable to support normal autophagosome biogenesis. Together, these studies make a compelling case for the direct role of a viral nonstructural protein in the formation and loading of the vesicular carriers used for non-lytic spread that may depend on the proper structure, accessibility, and/or dynamics of its LIR. The studies of PV 3CD protein reported here will hopefully provoke a more deliberate look at the presence and function of LIR motifs in viral proteins of viruses known to use autophagy as the basis for non-lytic spread.

IMPORTANCE

Poliovirus (PV) and other enteroviruses hijack the cellular secretory autophagy pathway for non-lytic virus transmission. While much is known about the cellular factors required for non-lytic transmission, much less is known about viral factors contributing to transmission. We have discovered a PV nonstructural protein required for multiple steps of the pathway leading to vesicle-enclosed virions. This discovery should facilitate the identification of the specific steps of the cellular secretory autophagy pathway and corresponding factors commandeered by the virus and may uncover novel targets for antiviral therapy.

Discovery of novel fused-heterocycle-bearing diarypyrimidine derivatives as HIV-1 potent NNRTIs targeting tolerant region I for enhanced antiviral activity and resistance profile

As an important part of anti-AIDS therapy, HIV-1 non-nucleoside reverse transcriptase inhibitors are plagued by resistance and toxicity issues. Taking our reported XJ-18b1 as lead compound, we designed a series of novel diarypyrimidine derivatives by employing a scaffold hopping strategy to discover potent NNRTIs with improved anti-resistance properties and drug-like profiles. The most active compound 3k exhibited prominent inhibitory activity against wild-type HIV-1 (EC50 = 0.0019 μM) and common mutant strains including K103 N (EC50 = 0.0019 μM), L100I (EC50 = 0.0087 μM), E138K (EC50 = 0.011 μM), along with low cytotoxicity and high selectivity index (CC50 = 21.95 μM, SI = 11478). Additionally, compound 3k demonstrated antiviral activity against HIV-2 with EC50 value of 6.14 μM. The enzyme-linked immunosorbent assay validated that 3k could significantly inhibit the activity of HIV-1 reverse transcriptase (IC50 = 0.025 μM). Furthermore, molecular dynamics simulation studies were performed to illustrate the potential binding mode and binding free energy of the RT-3k complex, and in silico prediction revealed that 3k possessed favorable drug-like profiles. Collectively, 3k proved to be a promising lead compound for further optimization to obtain anti-HIV drug candidates.

Drug Discovery and Exploration of Heterocycles for the Development of Anti-HIV Agents

It is a known fact that HIV infection remains a serious public health problem throughout the world, and the need to constantly develop new antiretroviral drugs to combat HIV emerges from the fact that repetitive mutations occurring in viral enzymes make this virus resistant to antiretroviral drugs. This resistance causes failure of treatment, and hence, for many years, extensive research has been to discover newer possibilities for fighting this disease at a molecular level, along with many long-standing and expensive clinical trials. Many scientific research programs have either been discarded or unsuccessful. However, the research has not stopped, and in the process, many heterocyclic scaffolds have been used to build up novel drug molecules to combat this disease. A literature survey reveals that many heterocycles have been explored and were found to be very useful in treating different types of viral infections. This concise and rigorous literature explains the journey and highlights the various strategies to develop new anti-HIV drug candidates.

Discovery of pentacyclic triterpene conjugates as HBV polymerase/NTCP dual-targeting inhibitors with potent anti-HBV activities

The inhibition of HBV DNA and elimination of HBsAg has already been established as an indicator for HBV clinic cure, and a novel dual-targeting inhibitors of HBV polymerase/entry are designed and synthesized in this study. Pentacyclic triterpenes (PTs) scaffold of exhibiting a high affinity to NTCP, including glycyrrhitinic acid (GA), oleanolic acid (OA), ursolic acid (UA), and betulinic acid (BA) were linked neatly with the nucleoside drug zidovudine (AZT) through a molecular hybrid strategy to synthesize twenty of PTs-AZT conjugates for targeting HBV polymerase as well as sodium taurocholate cotransporting polypeptide (NTCP). The conjugates showed significant inhibitory effects on the secretion of HBsAg and HBeAg in HepG2.2.15 cells, and the activity on HBsAg were better. Moreover, HBV DNA replication was also notably suppressed after incubated with the conjugates. The IC50 value of BA-AZT1 on HBsAg inhibition was 0.65 ± 0.07 μM, and it was 284.2 times and 442.2 times higher comparing to corresponding parent compound BA and AZT. Additionally, the therapeutic index (TI) was also improved by 87.8 times than AZT. And the IC50 value of BA-AZT1 on inhibition of HBV DNA replication was 0.70 ± 0.02 μM, 10.4 times higher than that of AZT besides conspicuous TI. Molecular docking suggested that AZT skeleton of conjugate BA-AZT1 interacted with B region of HBV Polymerase reverse transcription region, and BA structure simultaneously targeted to C region of polymerase via hydrophobic chain, establishing strong binding interactions with the HBV Pol protein. In addition, docked with NTCP, BA-AZT1 with flat pentacyclic structure inserted into the interface and also formed hydrogen bonds, hydrophobic and van der Waals forces with the amino residue 157-165 of NTCP. Further SPR analysis demonstrated the binding affinity of BA-AZT1 to C region of polymerase was 19.55 μM, stronger than 53.21 μM of BA and 31.82 μM of AZT. BA-AZT1 selectively bound to the 157-165 epitopes of NTCP receptors in host cell but not PreS1 of virus. As a result, we deduced that the designed conjugates targeted NTCP and HBV polymerase, not only prevented HBV from entering host cells via selective binding NTCP, but also inhibited HBV DNA replication through obstructing the function of HBV polymerase, and it could potentially serve as a promising dual-functional and dual-target inhibitor with both replication and entry inhibition to exert anti-HBV activity.

Evolution of hepatitis B virus polymerase and surface genes in patients receiving finite antiviral therapy

BACKGROUND AND AIM

Hepatitis B virus (HBV) reactivation could develop after withdrawal following a finite course of nucleoside analog (NA) therapy, leading to virological and clinical relapses. The genetic heterogeneity in the HBV surface and polymerase genes during finite NA therapy has not been carefully studied.

METHODS

Seven chronic HBV-infected patients experiencing relapses following entecavir (ETV; n = 5; Patients 1 to 5) or tenofovir disoproxil fumarate (TDF; n = 2; Patients 6 and 7) withdrawal were included. Sera obtained before treatment and at relapses were retrieved and submitted for DNA extraction and amplicon-specific deep sequencing.

RESULTS

ETV-treated patients had a longer time-to-relapse than that of TDF-treated patients (P = 0.0357). No drug-resistance related polymerase mutation was detected during relapses, except for a low percentage (1.4%) of rtM204I mutation in Patient 1. Two surface truncation mutations (sW216*; 40.9% and sW182*; 4.7%) detected before treatment in two TDF-treated patients (Patients 6 and 7, respectively) were overtaken by the wild types during subsequent drug-withdrawal-related relapses. The simultaneous presence of sG44E (T-cell epitope) and sE164G (B-cell epitope) mutations was associated with failure of HBV e antigen (HBeAg) seroclearance in ETV-treated patients.

CONCLUSIONS

In conclusion, HBV genome continues to evolve during the courses of finite antiviral therapies. Pre-existing surface truncation mutations can be overtaken by the wild types after relapses. The sG44E/sE164G mutations are associated with failure of HBeAg seroclearance.

p62 Binding to Protein Kinase C Regulates HIV-1 gp120 V3 Loop Induced Microglial Inflammation

The main pathogenic mechanism of HIV-associated neurocognitive disorders (HAND) is neuronal apoptosis induced by inflammatory mediators, in which microglial inflammation plays a crucial role. However, the exact pathogenic mechanism remains unclear. Previous studies have shown that the HIV-1 gp120 V3 loop can trigger inflammation in CHME-5 microglia. p62 is a post-translational modified multidomain protein that is involved in the regulation of autophagy and is closely related to neuroinflammation. In this study, we found that p62 knockout down-regulated the expression of MCP-1, IL-6 and COX-2, and improved the inflammation of HIV-1 gp120 V3 loop induced microglia, while overexpression of p62 up-regulated the expression of MCP-1, IL-6 and COX-2, and promoted the inflammation of microglia. In addition, protein kinase C (PKC) knockout down-regulated the expression of MCP-1, IL-6 and COX-2 and inhibited the activation of IKK/ NF-κ B pathway, while tumor necrosis factor receptor-associated factor 6 (TRAF6) knockout had no significant effect on the expression of MCP-1, IL-6 and COX-2. Co-immunoprecipitation showed that p62 was bound and interacted with PKC. Inhibition of IKK/ NF-κ B pathway can down-regulate the expression of MCP-1, IL-6 and COX-2, and improve the inflammatory response of microglia. Our research further found that inhibition of IKK/ NF-κ B can decrease the expression of Caspase-3 and reduce the apoptosis of neurons in the co-culture of CHME-5 microglia and primary mouse neurons. The results of this study suggest that HIV-1 gp120 V3 loop induced CHME-5 microglial inflammation may be activated by the direct binding of p62 and PKC through the IKK/ NF-κ B signaling pathway, and these findings provide an important reference for the prevention and treatment of HAND.

Sensitive quantification of fibroblast activation protein and high-throughput screening for inhibition by FDA-approved compounds

Fibroblast activation protein (FAP) has been extensively studied as a cancer biomarker for decades. Recently, small-molecule FAP inhibitors have been widely adopted as a targeting moiety of experimental theranostic radiotracers. Here we present a fast qPCR-based analytical method allowing FAP inhibition screening in a high-throughput regime. To identify clinically relevant compounds that might interfere with FAP-targeted approaches, we focused on a library of FDA-approved drugs. Using the DNA-linked Inhibitor Antibody Assay (DIANA), we tested a library of 2667 compounds within just a few hours and identified numerous FDA-approved drugs as novel FAP inhibitors. Among these, prodrugs of cephalosporin antibiotics and reverse transcriptase inhibitors, along with one elastase inhibitor, were the most potent FAP inhibitors in our dataset. In addition, by employing FAP DIANA in the quantification mode, we were able to determine FAP concentrations in human plasma samples. Together, our work expands the repertoire of FAP inhibitors, analyzes the potential interference of co-administered drugs with FAP-targeting strategies, and presents a sensitive and low-consumption ELISA alternative for FAP quantification with a detection limit of 50 pg/ml.

Targeting HBV cccDNA Levels: Key to Achieving Complete Cure of Chronic Hepatitis B

Chronic hepatitis B (CHB) caused by HBV infection has brought suffering to numerous people. Due to the stable existence of HBV cccDNA, the original template for HBV replication, chronic hepatitis B (CHB) is difficult to cure completely. Despite current antiviral strategies being able to effectively limit the progression of CHB, complete CHB cure requires directly targeting HBV cccDNA. In this review, we discuss strategies that may achieve a complete cure of CHB, including inhibition of cccDNA de novo synthesis, targeting cccDNA degradation through host factors and small molecules, CRISP-Cas9-based cccDNA editing, and silencing cccDNA epigenetically.

Technologies for Targeted RNA Degradation and Induced RNA Decay

The vast majority of the human genome codes for RNA, but RNA-targeting therapeutics account for a small fraction of approved drugs. As such, there is great incentive to improve old and develop new approaches to RNA targeting. For many RNA targeting modalities, just binding is not sufficient to exert a therapeutic effect; thus, targeted RNA degradation and induced decay emerged as powerful approaches with a pronounced biological effect. This review covers the origins and advanced use cases of targeted RNA degrader technologies grouped by the nature of the targeting modality as well as by the mode of degradation. It covers both well-established methods and clinically successful platforms such as RNA interference, as well as emerging approaches such as recruitment of RNA quality control machinery, CRISPR, and direct targeted RNA degradation. We also share our thoughts on the biggest hurdles in this field, as well as possible ways to overcome them.

Chronic Hepatitis B Genotype C Mouse Model with Persistent Covalently Closed Circular DNA

Hepatitis B virus (HBV) can cause chronic infections, significantly increasing the risk of death from cirrhosis and hepatocellular carcinoma (HCC). A key player in chronic HBV infection is covalently closed circular DNA (cccDNA), a stable episomal form of viral DNA that acts as a persistent reservoir in infected hepatocytes and drives continuous viral replication. Despite the development of several animal models, few adequately replicate cccDNA formation and maintenance, limiting our understanding of its dynamics and the evaluation of potential therapeutic interventions targeting cccDNA. In this study, we aimed to develop a mouse model to investigate cccDNA formation and maintenance. We infected C57BL/6 mice with recombinant adeno-associated virus (rAAV) carrying a 1.3-overlength HBV genome (genotype C) and collected liver tissue at various time points to assess cccDNA levels and viral replication. Our results demonstrated the successful establishment of a chronic hepatitis B mouse model using rAAV-HBV1.3, which supported persistent HBV infection with sustained cccDNA expression in hepatocytes. Serum levels of HBsAg and HBeAg were elevated for up to 12 weeks, while alanine transaminase (ALT) levels remained within the normal range, indicating limited liver damage during this period. We confirmed HBV DNA expression in hepatocytes, and importantly, cccDNA was detected using qPCR after Plasmid-Safe ATP-Dependent DNase treatment, which selectively removes non-cccDNA forms. Additionally, Southern blot analysis confirmed the presence of cccDNA isolated using the Hirt extraction method. This established model provides a valuable platform for studying the long-term maintenance of cccDNA in chronic HBV infection and offers an important tool for testing novel therapeutic strategies aimed at targeting cccDNA.

Novel mechanistic insights - A brand new Era for anti-HBV drugs

Hepatitis B Virus (HBV) remains a critical global health issue, with substantial morbidity and mortality. Current therapies, including interferons and nucleoside analogs, often fail to achieve complete cure or functional eradication. This review explores recent advances in anti-HBV agents, focusing on their innovative mechanisms of action. HBV entry inhibitors target the sodium taurocholate cotransporting polypeptide (NTCP) receptor, impeding viral entry, while nucleus translocation inhibitors disrupt key viral life cycle steps, preventing replication. Capsid assembly modulators inhibit covalently closed circular DNA (cccDNA) formation, aiming to eradicate the persistent viral reservoir. Transcription inhibitors targeting cccDNA and integrated DNA offer significant potential to suppress HBV replication. Immunomodulatory agents are highlighted for their ability to enhance host immune responses, facil-itating better control and possible eradication of HBV. These novel approaches represent significant advancements in HBV therapy, providing new strategies to overcome current treatment limitations. The development of cccDNA reducers is particularly critical, as they directly target the persistent viral reservoir, offering a promising pathway towards achieving a functional cure or complete viral eradication. Continued research in this area is essential to advance the effectiveness of anti-HBV therapies.