CCR5 as a Coreceptor for Human Immunodeficiency Virus and Simian Immunodeficiency Viruses: A Prototypic Love-Hate Affair

Tracing the evolutionary history of the CCR5delta32 deletion via ancient and modern genomes

The chemokine receptor variant CCR5delta32 is linked to HIV-1 resistance and other conditions. Its evolutionary history and allele frequency (10%-16%) in European populations have been extensively debated. We provide a detailed perspective of the evolutionary history of the deletion through time and space. We discovered that the CCR5delta32 allele arose on a pre-existing haplotype consisting of 84 variants. Using this information, we developed a haplotype-aware probabilistic model to screen 934 low-coverage ancient genomes and traced the origin of the CCR5delta32 deletion to at least 6,700 years before the present (BP) in the Western Eurasian Steppe region. Furthermore, we present strong evidence for positive selection acting upon the CCR5delta32 haplotype between 8,000 and 2,000 years BP in Western Eurasia and show that the presence of the haplotype in Latin America can be explained by post-Columbian genetic exchanges. Finally, we point to complex CCR5delta32 genotype-haplotype-phenotype relationships, which demand consideration when targeting the CCR5 receptor for therapeutic strategies.

Pathogenesis of HIV-associated depression: contributing factors and underlying mechanisms

Cumulative evidence indicates that compared to HIV negative individuals, people living with HIV (PLWH) have a higher likelihood of developing depression, anxiety, and cognitive disorders. Depression, which is known to be a persistent and overwhelming feeling of sadness accompanied by a loss of interest in usual activities, is one of the most common mental illnesses encountered during HIV infection. Experts believe that several factors such as neuroinflammation, life stressors, lack of sleep, poor nutritional state, opportunistic infections and comorbidities, and HIV medications are contributing factors favoring the development of depression in PLWH. However, the fundamental mechanisms which underlie the involvement of these factors in the emergence of depression in the context of HIV remain poorly explored. Past researches describing the role of one or two of the preceding factors do exist; however, very few articles tackle this important topic while considering the several different putative causative factors comprehensively in the particular context of HIV infection. Herein, we elaborate on the factors currently understood to be responsible for the development of depression, and discuss the particular fundamental mechanisms whereby each factor may result in the outcome of depression. We believe that the understanding of these factors and of their underlying mechanisms is essential for the development of future therapeutic interventions to alleviate the burden of depression commonly seen in PLWH, and therefore facilitate the development of strategies to improve their overall quality of life.

Addition of a short HIV-1 fusion-inhibitory peptide to PRO 140 antibody dramatically increases its antiviral breadth and potency

PRO 140, a humanized anti-HIV monoclonal antibody targeting the cell coreceptor CCR5, is currently under clinical trials, but it only affects CCR5-tropic viruses. In this study, we have engineered two tandem fusion proteins (2P23-PRO140SC and 2P23-PRO140-Fc) with bifunctional activity by adding short fusion-inhibitory peptide 2P23 to the single-chain fragment variable (scFv) of PRO 140 (PRO140SC) with or without the Fc domain of human IgG4. We first demonstrated that 2P23-PRO140SC and 2P23-PRO140-Fc could efficiently bind to the cell membranes through CCR5 anchoring, which did not affect the expression level of CCR5 on the cell surface. We then verified that the addition of 2P23 peptide to PRO140SC enabled a very potent activity against CXCR4-tropic HIV-1 isolates. As expected, the bispecific fusion proteins exhibited highly potent activities in inhibiting divergent HIV-1 subtypes and viral mutants that were resistant to the fusion inhibitors 2P23 and T20, and they displayed relatively low in vitro cytotoxicity. Furthermore, both the fusion proteins had robust in vivo anti-HIV activities in rats, with 2P23-PRO140-Fc much better than 2P23-PRO140SC. In conclusion, our studies have provided bispecific HIV-1 inhibitors that overcome the drawbacks of PRO 140 antibody and offered novel tools for studying the mechanisms of HIV-1 infection.IMPORTANCEGiven that HIV-1 evolves with high variability and drug resistance, the development of novel antivirals is important. CCR5-directed antibody PRO 140 is currently under clinical trials, but it only inhibits CCR5-tropic HIV-1 isolates. The designed fusion proteins by adding a minimum fusion-inhibitory peptide to PRO 140 enable dramatically increased activities in inhibiting both CCR5-tropic and CXCR4-tropic viruses, thus offering novel antiviral agents with a bispecific functionality that can overcome the drawbacks of PRO 140 antibody.

Nampt: a new therapeutic target for modulating NAD+ levels in metabolic, cardiovascular, and neurodegenerative diseases

NAD+ is an important cofactor involved in regulating many biochemical processes in cells. An imbalance in NAD+/NADH ratio is linked to many diseases. NAD+ is depleted in diabetes, cardiovascular and neurodegenerative diseases, and in aging, and is increased in tumor cells. NAD+ is generated in cells via the de novo, Preiss-Handler, and salvage pathways. Most of the cellular NAD+ is generated through Nampt activation, a key rate-limiting enzyme that is involved in the salvage pathway. Restoration of NAD+/NADH balance offers therapeutic advantages for improving tissue homeostasis and function. NAD+ is known to benefit and restore the body's physiological mechanisms, including DNA replication, chromatin and epigenetic modifications, and gene expression. Recent studies elucidate the role of NAD+ in cells utilizing transgenic mouse models. Translational new therapeutics are positioned to utilize the NAD+ restoration strategies for overcoming the drawbacks that exist in the pharmacological toolkit. The present review highlights the significance of Nampt-NAD+ axis as a major player in energy metabolism and provides an overview with insights into future strategies, providing pharmacological advantages to address current and future medical needs.

HIV viremic non-progressors: More clues and more questions

Viremic non-progressors are a unique subset of untreated people living with HIV who remarkably maintain high CD4+ T cell counts despite continuous high plasma viral loads. To better understand this rare phenotype, Bayón-Gil et al. explored host genetic and immunologic factors distinguishing viremic non-progressors from individuals with progressive disease.

Repurposing lapatinib as a triple antagonist of chemokine receptors 3, 4, and 5

Chemokine receptors CCR3, CCR4, and CCR5 are G protein-coupled receptors implicated in diseases like cancer, Alzheimer's, asthma, human immunodeficiency virus (HIV), and macular degeneration. Recently, CCR3 and CCR4 have emerged as potential stroke targets. Although only the CCR5 antagonist maraviroc is US Food and Drug Administration-approved (for HIV), we curated data on CCR3, CCR4, and CCR5 antagonists from ChEMBL to develop and validate machine learning models. The top 5-fold cross-validation statistics for these models were high for both classification and regression models for CCR3 (receiver operating characteristic [ROC], 0.94; R2 = 0.8), CCR4 (ROC, 0.98; R2 = 0.57), and CCR5 (ROC, 0.96; R2 = 0.78). The models for CCR3/4 were used to screen a small library of US Food and Drug Administration-approved drugs and 17 were initially tested in vitro against both CCR3/4 receptors. A promising compound lapatinib, a dual tyrosine kinase inhibitor, was identified as an antagonist for CCR3 (IC50, 0.7 μM) and CCR4 (IC50, 1.8 μM). Additional testing also identified it as an CCR5 antagonist (IC50, 0.9 μM), and it showed moderate in vitro HIV I inhibition. We demonstrated how machine learning can be used to identify molecules for repurposing as antagonists for G protein-coupled receptors such as CCR3, CCR4, and CCR5. Lapatinib may represent a new orally available chemical probe for these 3 receptors, and it provides a starting point for further chemical optimization for multiple diseases impacting human health. SIGNIFICANCE STATEMENT: We describe the building of machine learning models for the chemokine receptors CCR3, CCR4, and CCR5 trained on data from the ChEMBL database. Using these models, we identified lapatinib as a potent inhibitor of CCR3, CCR4, and CCR5. Our study illustrates the potential of machine learning in identifying molecules for repurposing as antagonists for G protein-coupled receptors, including CCR3, CCR4, and CCR5, which have various therapeutic applications.

Rapid systemic spread and minimal immune responses following SIVsab intrarectal transmission in African green monkeys

African green monkeys (AGMs) are natural hosts of SIV whose infection does not progress to AIDS. Since early events of infection may be critical to pathogenesis in nonnatural hosts, we investigated early SIV infection in 29 adult male AGMs intrarectally inoculated with SIVsab92018 (SIVsab) and serially sacrificed throughout acute into early chronic infection to understand patterns of viral establishment, dissemination, and their effect on disease progression. Using this model, we showed that foci of virus replication could be detected at the site of inoculation and in the draining lymphatics as early as 1-3 days postinfection (dpi). Furthermore, testing with ultrasensitive assays showed rapid onset of viremia (2-4 dpi). After systemic spread, virus was detected in all tissues surveyed. Multiple transmitted/founder viruses were identified, confirming an optimal challenge dose, while demonstrating a moderate mucosal genetic bottleneck. Resident CD4+ T cells were the initial target cells; other immune cell populations were not significantly altered at the site of entry. Thus, intrarectal SIVsab infection is characterized by swift dissemination of the virus, a lack of major target cell recruitment, and no window of opportunity for interventions to prevent virus dissemination during the earliest stages of infection, similar to intrarectal transmission but different from vaginal transmission in macaques.

SiRNAs as antiviral drugs - Current status, therapeutic potential and challenges

Traditionally, antiviral drugs target viral enzymes and or structural proteins, identified through large drug screens or rational drug design. The screening, chemical optimisation, small animal toxicity studies and clinical trials mean time to market is long for a new compound, and in the event of a novel virus or pandemic, weeks, and months matter. Small interfering RNAs (siRNAs) as a gene silencing platform is an alluring alternative. SiRNAs are now approved for use in the clinic to treat a range of diseases, are cost effective, scalable, and can be easily programmed to target any viral target in a matter of days. Despite the large number of preclinical studies that clearly show siRNAs are highly effective antivirals this has not translated into clinical success with no products on the market. This review provides a comprehensive overview of both the clinical and preclinical work in this area and outlines the challenges the field faces going forward that need to be addressed in order to see siRNA antivirals become a clinical reality.

Virulence and Replicative Fitness of HIV-1 Transmitted/Founder (T/F) Viruses Harbouring Drug Resistance-Associated Mutation

The biological characteristics of early transmitted/founder (T/F) variants are crucial factors for viral transmission and constitute key determinants for the development of better therapeutics and vaccine strategies. The present study aimed to generate T/F viruses and to characterize their biological properties. For this purpose, we constructed 18 full-length infectious molecular clones (IMCs) of HIV from recently infected infants. All the clones were characterized genotypically through whole genome sequencing and phenotypically for infectivity, replication kinetics, co-receptor usage, as well as their susceptibility to neutralizing antibodies and entry inhibitors using standard virological assays. Genotypic analysis revealed that all the T/F clones were of non-recombinant subtype C, but some of them harboured the Y181C drug resistance mutation associated with resistance to the non-nucleoside reverse transcriptase inhibitor (NNRTI) class of antiretroviral drugs. In vitro studies showed that while all the IMCs were capable of replicating in PBMCs and utilized the CCR5 co-receptor for cellular entry, the drug-resistant variants had significantly lower replicative capacity and per particle infectivity than the drug-sensitive viruses. Both exhibited similar sensitivities to a standard panel of broadly neutralizing monoclonal antibodies and viral entry inhibitors. These findings suggest that despite their diminished replicative fitness, the drug-resistant T/F variants retain transmission fitness and remain susceptible to neutralizing antibody-based interventions and viral entry inhibitors.

Exploring CCR5 + T regulatory cell subset dysfunction in type 1 diabetes patients: implications for immune regulation

T regulatory lymphocytes (Treg) expressing CCR5 exhibit strong suppression activity in various autoimmune disorders. However, there remains a lack of comprehensive understanding regarding their involvement in the development of type 1 diabetes (T1D). In this study, we examined the role of the CCR5/CCL5 axis in regulating inflammatory response and its impact on regulatory T cells in type 1 diabetes (T1D). We hypothesize that dysregulation of the CCR5/CCL5 axis contributes to the development and progression of T1D through modulation of Treg-dependent immune responses. We analyzed the expression levels of CCR5 on Tregs isolated from individuals with T1D, as well as the plasma concentration of its main ligands. We found that Tregs from T1D patients exhibited decreased expression of CCR5 compared to healthy controls. Additionally, we observed a correlation between the expression levels of CCR5 on Tregs and their immunosuppressive function in T1D patients. Our results indicate the impaired migratory capacity of CCR5 + Tregs, suggesting a possible link between the dysregulation of the CCR5/CCL5 axis and impaired immune regulation in T1D. In line with previous studies, our findings support the notion that dysregulation of the CCR5/CCL5 axis contributes to the development and progression of type 1 diabetes (T1D) by modulating Treg-dependent immune responses. The decreased expression of CCR5 on Tregs in T1D patients suggests a potential impairment in the migratory capacity of these cells, which could compromise their ability to suppress autoreactive T cells and maintain immune homeostasis. Furthermore, our study highlights the importance of CCR5 as a biomarker for identifying dysfunctional Tregs in T1D.

HIV vaccination: Navigating the path to a transformative breakthrough-A review of current evidence

Background and Aim

Human immunodeficiency virus (HIV) remains a significant global health challenge, with approximately 39 million people living with HIV worldwide as of 2022. Despite progress in antiretroviral therapy, achieving the UNAIDS "95-95-95" target to end the HIV epidemic by 2025 faces challenges, particularly in sub-Saharan Africa. The pursuit of an HIV vaccine is crucial, offering durable immunity and the potential to end the epidemic. Challenges in vaccine development include the lack of known immune correlates, suitable animal models, and HIV's high mutation rate. This study aims to explore the current state of HIV vaccine development, focusing on the challenges and innovative approaches being investigated.

Methods

In writing this review, we conducted a search of medical databases such as PubMed, ResearchGate, Web of Science, Google Scholar, and Scopus. The exploration of messenger ribonucleic acid vaccines, which have proven successful in the SARS-CoV-2 pandemic, presents a promising avenue for HIV vaccine development. Understanding HIV-1's ability to infiltrate various bodily compartments, establish reservoirs, and manipulate immune responses is critical. Robust cytotoxic T lymphocytes and broadly neutralizing antibodies are identified as key components, though their production faces challenges. Innovative approaches, including computational learning and advanced drug delivery systems, are being investigated to effectively activate the immune system.

Results and Conclusions

Discrepancies between animal models and human responses have hindered the progress of vaccine development. Despite these challenges, ongoing research is focused on overcoming these obstacles through advanced methodologies and technologies. Addressing the challenges in HIV vaccine development is paramount to realizing an effective HIV-1 vaccine and achieving the goal of ending the epidemic. The integration of innovative approaches and a deeper understanding of HIV-1's mechanisms are essential steps toward this transformative breakthrough.

T Cell Responses during Human Immunodeficiency Virus/Mycobacterium tuberculosis Coinfection

Coinfection with Mycobacterium tuberculosis (Mtb) and the human immunodeficiency virus (HIV) is a significant public health concern. Individuals infected with Mtb who acquire HIV are approximately 16 times more likely to develop active tuberculosis. T cells play an important role as both targets for HIV infection and mediators of the immune response against both pathogens. This review aims to synthesize the current literature and provide insights into the effects of HIV/Mtb coinfection on T cell populations and their contributions to immunity. Evidence from multiple in vitro and in vivo studies demonstrates that T helper responses are severely compromised during coinfection, leading to impaired cytotoxic responses. Moreover, HIV's targeting of Mtb-specific cells, including those within granulomas, offers an explanation for the severe progression of the disease. Herein, we discuss the patterns of differentiation, exhaustion, and transcriptomic changes in T cells during coinfection, as well as the metabolic adaptations that are necessary for T cell maintenance and functionality. This review highlights the interconnectedness of the immune response and the pathogenesis of HIV/Mtb coinfection.

Investigating the Potential Impact of CCR5-Δ32 Variant on COVID-19 Outcome: A Case-Control Study in Iranian Population

Background

The impact of CCR5-Δ32 on COVID-19 outcomes has been the focus of much research. This genetic variant may protect against SARS-CoV-2 infection, while others have produced conflicting results. Given the controversial results of previous research on different populations, we aimed to investigate the possible association between the CCR5-Δ32 variant and COVID-19 severity in an Iranian population.

Methods

This case-control study was conducted between 25th of April till 10th of October 2021 at Rasoul Akram Hospital of Iran University of Medical Sciences, Tehran, Iran. We investigated the association between CCR5-Δ32 genotype and COVID-19 severity in 200 unrelated Iranian patients. The patients were divided into 2 groups: 100 patients with severe COVID-19 (case group) and 100 patients with mild COVID-19 (control group). Genotyping of CCR5-Δ32 was performed using the polymerase chain reaction (PCR) technique.

Results

The frequency of CCR5-Δ32 allele was 11 in the case group and 16 in the control group. However, no significant association was found between this genetic variant and the clinical outcomes of COVID-19.

Conclusion

The CCR5-Δ32 variant cannot serve as a reliable predictive factor for identifying individuals prone to developing severe COVID-19 in Iranian population. Additionally, targeting CCR5 would not be a viable treatment approach for COVID-19 in Iranians.

Inclusion body myositis, viral infections, and TDP-43: a narrative review

The ubiquitous RNA-processing molecule TDP-43 is involved in neuromuscular diseases such as inclusion body myositis, a late-onset acquired inflammatory myopathy. TDP-43 solubility and function are disrupted in certain viral infections. Certain viruses, high viremia, co-infections, reactivation of latent viruses, and post-acute expansion of cytotoxic T cells may all contribute to inclusion body myositis, mainly in an age-shaped immune landscape. The virally induced senescent, interferon gamma-producing cytotoxic CD8+ T cells with increased inflammatory, and cytotoxic features are involved in the occurrence of inclusion body myositis in most such cases, in a genetically predisposed host. We discuss the putative mechanisms linking inclusion body myositis, TDP-43, and viral infections untangling the links between viruses, interferon, and neuromuscular degeneration could shed a light on the pathogenesis of the inclusion body myositis and other TDP-43-related neuromuscular diseases, with possible therapeutic implications.

An in vitro study to elucidate the effects of product Nkabinde on immune response in peripheral blood mononuclear cells of healthy donors

Introduction: A significant number of the South African population still rely on traditional medicines (TM) as their primary healthcare due to their belief in their holistic healing and immune-boosting properties. However, little to no scientific data is available on the effects of most TM products on cytokine and cellular biomarkers of the immune response. Here, we evaluated the impact of traditional medicine [Product Nkabinde (PN)] in inducing cellular and cytokine biomarkers of inflammation in peripheral blood mononuclear cells (PBMCs) from eight healthy volunteers. Methods: PN was supplied by a local Traditional Health Practitioner (THP). The IC50 (half maximum concentration) of the standardized extract on isolated PBMCs was established using the cell viability assay over 24 h of incubation. Luminex and flow cytometry assays were used to measure cytokine and cellular levels in PBMCs stimulated with PN and/or PHA over 24, 48, and 72 h, respectively. Results: The IC50 concentration of PN in treated PBMCs was established at 325.3 μg/mL. In the cellular activation assay, the percentages of CD38-HLA-DR + on total CD4+ T cells were significantly increased in PBMCs stimulated with PN compared to unstimulated controls after 24 h (p = 0.008). PN significantly induced the production of anti-inflammatory IL-10 (p = 0.041); proinflammatory cytokines IL-1α (p = 0.003), TNF-α (p < 0.0001); and chemokine MIP-1β (p = 0.046) compared to the unstimulated control after 24 h. At 48 h incubation, the production of proinflammatory cytokines IL-1α (p = 0.034) and TNF-α (p = 0.011) were significantly induced following treatment with PN. Conclusion: We conclude that the PN possesses in vitro immunomodulatory properties that may influence immune and inflammatory responses. More studies using PN are needed to further understand key parameters mediating induction, expression, and regulation of the immune response in the context of pathogen-associated infections.

The chemokine receptor CCR5: multi-faceted hook for HIV-1

Chemokines are cytokines whose primary role is cellular activation and stimulation of leukocyte migration. They perform their various functions by interacting with G protein-coupled cell surface receptors (GPCRs) and are involved in the regulation of many biological processes such as apoptosis, proliferation, angiogenesis, hematopoiesis or organogenesis. They contribute to the maintenance of the homeostasis of lymphocytes and coordinate the function of the immune system. However, chemokines and their receptors are sometimes hijacked by some pathogens to infect the host organism. For a given chemokine receptor, there is a wide structural, organizational and conformational diversity. In this review, we describe the evidence for structural variety reported for the chemokine receptor CCR5, how this variability can be exploited by HIV-1 to infect its target cells and what therapeutic solutions are currently being developed to overcome this problem.

Advancements in Cell-Based Therapies for HIV Cure

The treatment of human immunodeficiency virus (HIV-1) has evolved since the establishment of combination antiretroviral therapy (ART) in the 1990s, providing HIV-infected individuals with approaches that suppress viral replication, prevent acquired immunodeficiency syndrome (AIDS) throughout their lifetime with continuous therapy, and halt HIV transmission. However, despite the success of these regimens, the global HIV epidemic persists, prompting a comprehensive exploration of potential strategies for an HIV cure. Here, we offer a consolidated overview of cell-based therapies for HIV-1, focusing on CAR-T cell approaches, gene editing, and immune modulation. Persistent challenges, including CAR-T cell susceptibility to HIV infection, stability, and viral reservoir control, underscore the need for continued research. This review synthesizes current knowledge, highlighting the potential of cellular therapies to address persistent challenges in the pursuit of an HIV cure.

A Pocket Guide to CCR5-Neurotropic Flavivirus Edition

CCR5 is among the most studied chemokine receptors due to its profound significance in human health and disease. The notion that CCR5 is a functionally redundant receptor was challenged through the demonstration of its unique protective role in the context of West Nile virus in both mice and humans. In the nearly two decades since this initial discovery, numerous studies have investigated the role of CCR5 in the context of other medically important neurotropic flaviviruses, most of which appear to support a broad neuroprotective role for this receptor, although how CCR5 exerts its protective effect has been remarkably varied. In this review, we summarize the mechanisms by which CCR5 controls neurotropic flaviviruses, as well as results from human studies evaluating a genetic link to CCR5, and propose unexplored areas of research that are needed to unveil even more exciting roles for this important receptor.

Association of Viral and Host Genetic Architecture with the Status of Neurocognitive Disorder in HIV-Infected Individuals

The polymorphisms in host genes such as CCR5, CCR2, stromal derived factor (SDF), and MBL (mannose-binding lectin) as well as the viral nef gene have been shown to influence human immunodeficiency virus (HIV) infection, followed by the development of HIV-associated neurocognitive disorder (HAND). In this preliminary study with a limited number of samples, we have tried to associate the genetic polymorphism from the host and viral genetic factors with the neurocognitive status along with immuno-virological parameters. The total RNA was isolated from 10 unlinked plasma samples containing 5 samples from each group with and without HAND based on the International HIV Dementia Scale (IHDS) score <9.5 and >9.5, respectively. The CCR5, CCR2, SDF, MBL, and HIV nef genes were amplified and digested with restriction enzymes, except for the nef gene amplicon. Restrictions fragment length polymorphism (RFLP) was used to determine whether allelic variations were present in the digested host gene products, while sequencing was done for HIV nef amplicons without digestion. CCR5 delta 32 heterozygous variants were present in two samples from the HAND group. Three samples with HAND showed SDF-1 3' heterozygous allelic variant, while the MBL-2 gene presented with a homozygous mutant allele (D/D) in codon 52, heterozygous mutant allele (A/B) in codon 54, and codon 57 (A/C) for all samples except IHDS-2 irrespective of dementia status. Furthermore, amino acid alignment of Nef sequences confirmed the heterogeneity, while prediction of the human leukocyte antigen binding epitopes further explored its effect on functional motifs with variable binding efficiency such as epitopes GAFDLSFFL (aa 83) and LTFGWCFKL (aa 138) binding with HLA molecules at 60% and 80%, respectively. Thus, host genetics evidently influence predisposition to HIV infection and HAND. The genetic variability in the nef gene from both groups resulted in altering the functionality of specific domains and showing its impact on the progression of the disease, which needs to be explored.

Adverse effect of VEGFR-2 (rs1870377) polymorphism on the clinical course of COVID-19 in females and males in an age-dependent manner

The COVID-19 pandemic has affected people worldwide with varying clinical presentations ranging from mild to severe or fatal, and studies have found that age, gender, and some comorbidities can influence the severity of the disease. It would be valuable to have genetic markers that might help predict the likely outcome of infection. For this objective, genes encoding VEGFR-2 (rs1870377), CCR5Δ32 (rs333), and TLR3 (rs5743313) were analyzed for polymorphisms in the peripheral blood of 160 COVID-19 patients before COVID-19 vaccine was available in Türkiye. We observed that possession of the VEGFR-2 rs1870377 mutant allele increased the risk of severe/moderate disease in females and subjects ≥65 years of age, but was protective in males <65 years of age. Other significant results were that the CCR5Δ32 allele was protective against severe disease in subjects ≥65 years of age, while TLR3 rs5743313 polymorphism was found to be protective against severe/moderate illness in males <65 years of age. The VEGFR-2 rs1870377 mutant allele was a risk factor for severe/moderate disease, particularly in females over the age of 65. These findings suggest that genetic polymorphisms have an age- and sex-dependent influence on the severity of COVID-19, and the VEGFR-2 rs1870377 mutant allele could be a potential predictor of disease severity.

Intravenous Bacille Calmette-Guérin vaccination protects simian immunodeficiency virus-infected macaques from tuberculosis

Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), is the most common cause of death in people living with human immunodeficiency virus (HIV). Intra-dermal Bacille Calmette-Guérin (BCG) delivery is the only licensed vaccine against tuberculosis; however, it offers little protection from pulmonary tuberculosis in adults and is contraindicated in people living with HIV. Intravenous BCG confers protection against Mtb infection in rhesus macaques; we hypothesized that it might prevent tuberculosis in simian immunodeficiency virus (SIV)-infected macaques, a model for HIV infection. Here intravenous BCG-elicited robust airway T cell influx and elevated plasma and airway antibody titres in both SIV-infected and naive animals. Following Mtb challenge, all 7 vaccinated SIV-naive and 9 out of 12 vaccinated SIV-infected animals were protected, without any culturable bacteria detected from tissues. Peripheral blood mononuclear cell responses post-challenge indicated early clearance of Mtb in vaccinated animals, regardless of SIV infection. These data support that intravenous BCG is immunogenic and efficacious in SIV-infected animals.

Next generation 3D-printed intravaginal ring for prevention of HIV and unintended pregnancy

Globally, there are 20 million adolescent girls and young women living with HIV who have limited access to long-acting, effective, women-controlled preventative methods. Additionally, although there are many contraceptive methods available, globally, half of all pregnancies remain unintended. Here we report the first 3D-printed multipurpose prevention technology (MPT) intravaginal ring (IVR) for HIV prevention and contraception. We utilized continuous liquid interface production (CLIP™) to fabricate MPT IVRs in a biocompatible silicone-based resin. Etonogestrel (ENG), ethinyl estradiol (EE), and islatravir (ISL) were loaded into the silicone poly(urethane) IVR in a controlled single step drug loading process driven by absorption. ENG/EE/ISL IVR promoted sustained release of drugs for 150 days in vitro and 14 days in sheep. There were no adverse MPT IVR-related findings of cervicovaginal toxicity or changes in vaginal biopsies or microbiome community profiles evaluated in sheep. Furthermore, ISL IVR in macaques promoted sustained release for 28 days with ISL-triphosphate levels above the established pharmacokinetic benchmark of 50-100 fmol/106 PBMCs. The ISL IVR was found to be safe and well tolerated in the macaques with no observed mucosal cytokine changes or alterations in peripheral CD4 T-cell populations. Collectively, the proposed MPT IVR has potential to expand preventative choices for young women and girls.

The Potential Role of RANTES in Post-Stroke Therapy

One of the key response mechanisms to brain damage, that results in neurological symptoms, is the inflammatory response. It triggers processes that exacerbate neurological damage and create the right environment for the subsequent repair of damaged tissues. RANTES (Regulated upon Activation, Normal T Cell Expressed and Presumably Secreted) chemokine(C-C motif) ligand 5 (CCL5) is one of the chemokines that may have a dual role in stroke progression involving aggravating neuronal damage and playing an important role in angiogenesis and endothelial repair. This study concerned patients with ischemic stroke (AIS), whose CCL5 concentration was measured at various time intervals and was compared with the control group. In addition, the effect of this biomarker on neurological severity and functional prognosis was investigated. Compared to healthy patients, a higher concentration of this chemokine was demonstrated in less than 4.5 h, 24 h and on the seventh day. Differences in CCL5 levels were found to be dependent on the degree of disability and functional status assessed according to neurological scales (modified Rankin Scale, National Institutes of Health Stroke Scale). In addition, differences between various subtypes of stroke were demonstrated, and an increase in CCL5 concentration was proven to be a negative predictor of mortality in patients with AIS. The deleterious effect of CCL5 in the acute phase of stroke and the positive correlation between the tested biomarkers of inflammation were also confirmed.

Prevalence of CCR5 Delta 32 Genetic Variant in the Turkmen Population of Golestan Province, Northeast of Iran

The 32 bp deletion in the chemokine receptor (C-C motif) 5 gene (CCR5Δ32) is a natural loss of function polymorphism that prevents the protein from locating on the cell surface. This genetic variation acts as a double-edge sword in the pathogenesis/defense mechanism of different health conditions, such as viral infections, autoimmune diseases, and cancers. Here, we evaluated the prevalence of the CCR5Δ32 polymorphism in the Turkmen population of Golestan province, northeast of Iran. Blood samples were collected from 400 randomly selected Turkmen populations (199 women and 201 men), and genomic DNA was extracted. Characterization of CCR5Δ32 genotypes was performed by PCR using primers flanking the 32-nucleotide deletion in the CCR5 gene. The amplified DNA fragments were visualized on 2% agarose gel electrophoresis with cybergreen staining under UV light. All individuals were of Turkmen ethnicity and lived in the Golestan province, northeast of Iran. The mean age of all participants was 35.46 years, with a 20-45 year range. All the studied subjects were healthy without any severe conditions such as autoimmune disease and viral infections. All individuals had no history of HIV infection. The PCR product visualization showed that all the samples are at the 330 bp size, which means the CCR5Δ32 allele was utterly absent from the study population. The presence of the CCR5Δ32 allele among Turkmens may be attributed to the admixture with European descent people. We conclude that the CCR5Δ32 polymorphism may be absent in the Iranian Turkmen population, and further studies with a large population are needed.

Vaccination with intravenous BCG protects macaques with pre-existing SIV infection from tuberculosis

Tuberculosis (TB) is the most common cause of death in people living with HIV. BCG delivered intradermally (ID) is the only licensed vaccine to prevent TB. However, it offers little protection from pulmonary TB in adults. Intravenous (IV) BCG, but not ID BCG, confers striking protection against Mycobacterium tuberculosis (Mtb) infection and disease in rhesus macaques. We investigated whether IV BCG could protect against TB in macaques with a pre-existing SIV infection. There was a robust influx of airway T cells following IV BCG in both SIV-infected and SIV-naïve animals, with elevated antibody titers in plasma and airways. Following Mtb challenge, all 7 SIV-naïve and 9 out of 12 SIV-infected vaccinated animals were completely protected, without any culturable bacilli in their tissues. PBMC responses post-challenge indicated early clearance of Mtb in vaccinated animals regardless of SIV infection. These data support that IV BCG is immunogenic and efficacious in SIV-infected animals.

Ascorbate formulation improves healing efficacy in excisional wound mice model through interplay between pro and anti-inflammatory cytokines and angiogenic markers

BACKGROUND AND OBJECTIVE

Biomedical research in regenerative medicine prompts researchers to formulate cost-effective therapeutics for wound healing. The present study was conducted to characterize the ascorbate based formulation vis-a-vis investigating the molecular dynamics of the formulation.

MATERIALS AND METHODS

To characterize the formulation, particle size, zeta potential, thermal stability, compatibility, anti-oxidant, and permeation prospective were measured using standard protocols. The in-vitro healing potential and safety formulae were evaluated using the L929 cell line. For molecular unravelling of the pharmacodynamics of formulation, an excision wound model was used, and 54 mice were randomly and equally divided into three groups, i.e., untreated, betadine-treated, and formulation-treated, to ascertain the interplay between cytokines and chemokines and their culminative role in the release of growth factors.

RESULTS

The ascorbate formulae were found to be amorphous, biocompatible, safe, and long-lasting, with particle sizes and zeta potentials of 389.7 ± 0.69 nm and -38.1 ± 0.65 mV, respectively, and anti-oxidative potential. An in-vitro study revealed that the formulation has a significant (p<0.05) migration potential and is non-toxic. Expression profiling of TGF-β, FGF-2, VEGF, and collagen III & I showed significant (p<0.05) up-regulation, whereas significant (p<0.05) down-regulation of pro-inflammatory genes like IL-1α, IL-1β, TNF-α, IL-6, and temporal change in CCR-5 was observed in formulae-treated animals as compared to other groups.

CONCLUSION

By up-regulating angiogenic and collagen-promoting growth factor gene expression while down-regulating pro-inflammatory gene expression, ascorbate formulation promotes wound healing via extracellular matrix and granulation tissue deposition with significant improvement in tensile strength.

Walk on the wild side: SIV infection in African non-human primate hosts-from the field to the laboratory

HIV emerged following cross-species transmissions of simian immunodeficiency viruses (SIVs) that naturally infect non-human primates (NHPs) from Africa. While HIV replication and CD4+ T-cell depletion lead to increased gut permeability, microbial translocation, chronic immune activation, and systemic inflammation, the natural hosts of SIVs generally avoid these deleterious consequences when infected with their species-specific SIVs and do not progress to AIDS despite persistent lifelong high viremia due to long-term coevolution with their SIV pathogens. The benign course of natural SIV infection in the natural hosts is in stark contrast to the experimental SIV infection of Asian macaques, which progresses to simian AIDS. The mechanisms of non-pathogenic SIV infections are studied mainly in African green monkeys, sooty mangabeys, and mandrills, while progressing SIV infection is experimentally modeled in macaques: rhesus macaques, pigtailed macaques, and cynomolgus macaques. Here, we focus on the distinctive features of SIV infection in natural hosts, particularly (1): the superior healing properties of the intestinal mucosa, which enable them to maintain the integrity of the gut barrier and prevent microbial translocation, thus avoiding excessive/pathologic immune activation and inflammation usually perpetrated by the leaking of the microbial products into the circulation; (2) the gut microbiome, the disruption of which is an important factor in some inflammatory diseases, yet not completely understood in the course of lentiviral infection; (3) cell population shifts resulting in target cell restriction (downregulation of CD4 or CCR5 surface molecules that bind to SIV), control of viral replication in the lymph nodes (expansion of natural killer cells), and anti-inflammatory effects in the gut (NKG2a/c+ CD8+ T cells); and (4) the genes and biological pathways that can shape genetic adaptations to viral pathogens and are associated with the non-pathogenic outcome of the natural SIV infection. Deciphering the protective mechanisms against SIV disease progression to immunodeficiency, which have been established through long-term coevolution between the natural hosts and their species-specific SIVs, may prompt the development of novel therapeutic interventions, such as drugs that can control gut inflammation, enhance gut healing capacities, or modulate the gut microbiome. These developments can go beyond HIV infection and open up large avenues for correcting gut damage, which is common in many diseases.

Do CCR5 (CCR5Δ32) and TLR3 (RS5743313) gene polymorphisms prevent chronic hepatitis B infection?

Hepatitis B virus (HBV) is still a significant health problem in human. HBV severity or sensitivity of patients may be based on the individual genetic factors significantly. The aim of this study is to investigate the association of CCR5 (CCR5Δ32), TLR3 (rs5743313) functional gene polymorphisms, interferon-gamma (IFN-ɣ) level in HBV infection, which are thought to play an important role in innate and acquired immunity in patients who have undergone HBV seroconversion and those who have chronic hepatitis B disease and receive treatment. One hundred patients who are became naturally immune against HBV infection (HBsAg negative, anti-HBc IgG, and anti-HBs IgG positive), and 100 patients with chronic hepatitis B infection (>6 months HBsAg positive) who are receiving oral antiviral therapy were compared for CCR5Δ32, TLR3 (rs5743313) genotypes and serum IFN-ɣ level. It was found that CCR5Δ32 polymorphism (Wt/Δ32 and Δ32/Δ32) was significantly higher in the chronic hepatitis B group (p = 0.048) but not for TLR3 gene polymorphism. However, serum IFN-ɣ level was significantly higher in the HBV seroconversion group (75 ± 89 ng/ml) than in the chronic hepatitis B group (4.35 ± 17.27 ng/ml) (p < 0.001). In conclusion, a higher CCR5Δ32 allele frequency in patients with chronic hepatitis B might be considered as a marker of progression to chronic hepatitis.

The Elusive Coreceptors for the SARS-CoV-2 Spike Protein

Evidence suggests that the N-terminal domain (NTD) of the SARS-CoV-2 spike protein interacts with host coreceptors that participate in viral entry. Resolving the identity of coreceptors has important clinical implications as it may provide the basis for the development of antiviral drugs and vaccine candidates. The majority of characteristic mutations in variants of concern (VOCs) have occurred in the NTD and receptor binding domain (RBD). Unlike the RBD, mutations in the NTD have clustered in the most flexible parts of the spike protein. Many possible coreceptors have been proposed, including various sugars such as gangliosides, sialosides, and heparan sulfate. Protein coreceptors, including neuropilin-1 and leucine-rich repeat containing 15 (LRRC15), are also proposed coreceptors that engage the NTD.

Unique profile of predominant CCR5-tropic in CRF07_BC HIV-1 infections and discovery of an unusual CXCR4-tropic strain

CRF07_BC is one of the most prevalent HIV-1 strains in China, which contributes over one-third of the virus transmissions in the country. In general, CRF07_BC is associated with slower disease progression, while the underlying mechanisms remain unclear. Our study focused on envelope proteins (Env) and its V3 loop which determine viral binding to co-receptors during infection of cells. We studied a large dataset of 3,937 env sequences in China and found that CRF07_BC had a unique profile of predominantly single CCR5 tropism compared with CCR5 and CXCR4 dual tropisms in other HIV-1 subtypes. The percentages of the CXCR4-tropic virus in B (3.7%) and CRF01_AE (10.4%) infection are much higher than that of CRF07_BC (0.1%), which is supported by median false-positive rates (FPRs) of 69.8%, 25.5%, and 13.4% for CRF07_BC, B, and CRF01_AE respectively, with a cutoff FPR for CXCR4-tropic at 2%. In this study, we identified the first pure CXCR4-tropic virus from one CRF07_BC-infected patient with an extremely low CD4⁺T cell count (7 cells/mm³). Structural analysis found that the V3 region of this virus has the characteristic 7T and 25R and a substitution of conserved “GPGQ” crown motif for “GPGH”. This study provided compelling evidence that CRF07_BC has the ability to evolve into CXCR4 strains. Our study also lay down the groundwork for studies on tropism switch, which were commonly done for other HIV-1 subtypes, for the long-delayed CRF07_BC.

I've looked at gut from both sides now: Gastrointestinal tract involvement in the pathogenesis of SARS-CoV-2 and HIV/SIV infections

The lumen of the gastrointestinal (GI) tract contains an incredibly diverse and extensive collection of microorganisms that can directly stimulate the immune system. There are significant data to demonstrate that the spatial localization of the microbiome can impact viral disease pathogenesis. Here we discuss recent studies that have investigated causes and consequences of GI tract pathologies in HIV, SIV, and SARS-CoV-2 infections with HIV and SIV initiating GI pathology from the basal side and SARS-CoV-2 from the luminal side. Both these infections result in alterations of the intestinal barrier, leading to microbial translocation, persistent inflammation, and T-cell immune activation. GI tract damage is one of the major contributors to multisystem inflammatory syndrome in SARS-CoV-2-infected individuals and to the incomplete immune restoration in HIV-infected subjects, even in those with robust viral control with antiretroviral therapy. While the causes of GI tract pathologies differ between these virus families, therapeutic interventions to reduce microbial translocation-induced inflammation and improve the integrity of the GI tract may improve the prognoses of infected individuals.