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Viruses May 2024Repression of human cytomegalovirus (HCMV) immediate-early (IE) gene expression is a key regulatory step in the establishment and maintenance of latent reservoirs. Viral...
cGAS-STING-TBK1 Signaling Promotes Valproic Acid-Responsive Human Cytomegalovirus Immediate-Early Transcription during Infection of Incompletely Differentiated Myeloid Cells.
Repression of human cytomegalovirus (HCMV) immediate-early (IE) gene expression is a key regulatory step in the establishment and maintenance of latent reservoirs. Viral IE transcription and protein accumulation can be elevated during latency by treatment with histone deacetylase inhibitors such as valproic acid (VPA), rendering infected cells visible to adaptive immune responses. However, the latency-associated viral protein UL138 inhibits the ability of VPA to enhance IE gene expression during infection of incompletely differentiated myeloid cells that support latency. UL138 also limits the accumulation of IFNβ transcripts by inhibiting the cGAS-STING-TBK1 DNA-sensing pathway. Here, we show that, in the absence of UL138, the cGAS-STING-TBK1 pathway promotes both IFNβ accumulation and VPA-responsive IE gene expression in incompletely differentiated myeloid cells. Inactivation of this pathway by either genetic or pharmacological inhibition phenocopied UL138 expression and reduced VPA-responsive IE transcript and protein accumulation. This work reveals a link between cytoplasmic pathogen sensing and epigenetic control of viral lytic phase transcription and suggests that manipulation of pattern recognition receptor signaling pathways could aid in the refinement of MIEP regulatory strategies to target latent viral reservoirs.
Topics: Humans; Valproic Acid; Myeloid Cells; Signal Transduction; Membrane Proteins; Cytomegalovirus; Nucleotidyltransferases; Protein Serine-Threonine Kinases; Cytomegalovirus Infections; Virus Latency; Transcription, Genetic; Cell Differentiation; Gene Expression Regulation, Viral; Genes, Immediate-Early; Interferon-beta
PubMed: 38932169
DOI: 10.3390/v16060877 -
Viruses May 2024Treatment of hepatitis C among people who inject drugs (PWID) may be complicated by loss to follow-up and reinfection. We aimed to evaluate sustained virologic response...
Treatment of hepatitis C among people who inject drugs (PWID) may be complicated by loss to follow-up and reinfection. We aimed to evaluate sustained virologic response (SVR) and reinfection, and to validate complete pharmacy dispensation as a proxy for cure among PWID enrolled in a trial of opportunistic HCV treatment. Data were obtained by reviewing the electronic patient files and supplemented by outreach HCV RNA testing. Reinfection was defined based on clinical, behavioral, and virological data. Intention to treat SVR ≥ 4 within 2 years after enrolment was accomplished by 59 of 98 (60% [95% CI 50-70]) during intervention conditions (opportunistic treatment) and by 57 of 102 (56% [95% CI 46-66]) during control conditions (outpatient treatment). The time to end of treatment response (ETR) or SVR ≥ 4 was shorter among intervention participants (HR 1.55 [1.08-2.22]; = 0.016). Of participants with complete dispensation, 132 of 145 (91%) achieved ETR or SVR > 4 (OR 12.7 [95% CI 4.3-37.8]; < 0.001). Four cases of reinfection were identified (incidence 3.8/100 PY [95% CI 1.0-9.7]). Although SVR was similar, the time to virologic cure was shorter among intervention participants. Complete dispensation is a valid correlate for cure among individuals at risk of loss to follow-up. Reinfection following successful treatment remains a concern.
Topics: Humans; Male; Female; Reinfection; Adult; Substance Abuse, Intravenous; Sustained Virologic Response; Middle Aged; Antiviral Agents; Hepacivirus; Follow-Up Studies; Hepatitis C; Treatment Outcome; Hospitalization; RNA, Viral
PubMed: 38932151
DOI: 10.3390/v16060858 -
Viruses May 2024The devastating effects of COVID-19 have highlighted the importance of prophylactic and therapeutic strategies to combat respiratory diseases. Stimulator of interferon...
The devastating effects of COVID-19 have highlighted the importance of prophylactic and therapeutic strategies to combat respiratory diseases. Stimulator of interferon gene (STING) is an essential component of the host defense mechanisms against respiratory viral infections. Although the role of the cGAS/STING signaling axis in the innate immune response to DNA viruses has been thoroughly characterized, mounting evidence shows that it also plays a key role in the prevention of RNA virus infections. In this study, we investigated the role of STING activation during Influenza virus (IFV) infection. In both mouse bone marrow-derived macrophages and monocytic cell line THP-1 differentiated with PMA, we found that dimeric amidobenzimidazole (diABZI), a STING agonist, had substantial anti-IFV activity against multiple strains of IFV, including A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. On the other hand, a pharmacological antagonist of STING (H-151) or the loss of STING in human macrophages leads to enhanced viral replication but suppressed IFN expression. Furthermore, diABZI was antiviral against IFV in primary air-liquid interface cultures of nasal epithelial cells. Our data suggest that STING agonists may serve as promising therapeutic antiviral agents to combat IFV.
Topics: Animals; Humans; Immunity, Innate; Mice; Antiviral Agents; Macrophages; Membrane Proteins; THP-1 Cells; Virus Replication; Influenza, Human; Dogs; Mice, Inbred C57BL; Orthomyxoviridae Infections; Orthomyxoviridae; Benzimidazoles; Signal Transduction
PubMed: 38932148
DOI: 10.3390/v16060855 -
Viruses May 2024The viral interferon regulatory factors (vIRFs) of KSHV are known to dysregulate cell signaling pathways to promote viral oncogenesis and to block antiviral immune...
The viral interferon regulatory factors (vIRFs) of KSHV are known to dysregulate cell signaling pathways to promote viral oncogenesis and to block antiviral immune responses to facilitate infection. However, it remains unknown to what extent each vIRF plays a role in gene regulation. To address this, we performed a comparative analysis of the protein structures and gene regulation of the four vIRFs. Our structure prediction analysis revealed that despite their low amino acid sequence similarity, vIRFs exhibit high structural homology in both their DNA-binding domain (DBD) and IRF association domain. However, despite this shared structural homology, we demonstrate that each vIRF regulates a distinct set of KSHV gene promoters and human genes in epithelial cells. We also found that the DBD of vIRF1 is essential in regulating the expression of its target genes. We propose that the structurally similar vIRFs evolved to possess specialized transcriptional functions to regulate specific genes.
Topics: Humans; Interferon Regulatory Factors; Herpesvirus 8, Human; Epithelial Cells; Viral Proteins; Gene Expression Regulation, Viral; Promoter Regions, Genetic; Transcription, Genetic; Genome, Viral; Cell Line
PubMed: 38932139
DOI: 10.3390/v16060846 -
Pharmaceuticals (Basel, Switzerland) Jun 2024The open-source drug library, namely, MMV Pandemic Response Box, contains 153 antiviral agents, a chemically and pharmacologically diverse mixture of early-stage,...
The open-source drug library, namely, MMV Pandemic Response Box, contains 153 antiviral agents, a chemically and pharmacologically diverse mixture of early-stage, emerging anti-infective scaffolds, and mature compounds currently undergoing clinical development. Hence, the Pandemic Response Box might contain compounds that bind and interfere with target molecules or cellular pathways that are conserved or shared among the closely related viruses with enterovirus A71 (EV-A71). This study aimed to screen antiviral agents included in the Pandemic Response Box for repurposing to anti-EV-A71 activity and investigate the inhibitory effects of the compounds on viral replication. The compounds' cytotoxicity and ability to rescue infected cells were determined by % cell survival using an SRB assay. The hit compounds were verified for anti-EV-A71 activity by virus reduction assays for viral RNA copy numbers, viral protein synthesis, and mature particle production using qRT-PCR, Western blot analysis, and CCID assay, respectively. It was found that some of the hit compounds could reduce EV-A71 genome replication and protein synthesis. D-D7 (2-pyridone-containing human rhinovirus 3C protease inhibitor) exhibited the highest anti-EV-A71 activity. Even though D-D7 has been originally indicated as a polyprotein processing inhibitor of human rhinovirus 3C protease, it could be repurposed as an anti-EV-A71 agent.
PubMed: 38931452
DOI: 10.3390/ph17060785 -
Pharmaceuticals (Basel, Switzerland) May 2024Microbicides, which are classified as topical antiseptic agents, are a revolutionary advancement in HIV prevention aimed to prevent the entry of infectious agents into... (Review)
Review
Microbicides, which are classified as topical antiseptic agents, are a revolutionary advancement in HIV prevention aimed to prevent the entry of infectious agents into the human body, thus stopping the sexual transmission of HIV and other sexually transmitted diseases. Microbicides represent the promise of a new age in preventive measures against one of the world's most pressing health challenges. In addition to their direct antiviral effects during HIV transmission, microbicides also influence vaginal mucosal immunity. This article reviews microbicides by presenting different drug classifications and highlighting significant representatives from each group. It also explains their mechanisms of action and presents information about vaginal mucosal immune responses, emphasizing the critical role they play in responding to HIV during sexual transmission. The article discusses the following groups of microbicides: surfactants or membrane disruptors, vaginal milieu protectors, anionic polymers, dendrimers, carbohydrate-binding proteins, HIV replication inhibitors (reverse transcriptase inhibitors), and multi-purpose prevention technologies, which combine protection against HIV, other sexually transmitted diseases, and contraception. For each chemical compound, the article provides a brief overview of relevant preclinical and clinical research, emphasizing their potential as microbicides. The article offers insights into the multifaceted impact of microbicides, which signify a pivotal step forward in the pursuit of effective and accessible pre-exposure prophylaxis (PrEP).
PubMed: 38931337
DOI: 10.3390/ph17060668 -
Nutrients Jun 2024The immune system is affected by the dietary products humans intake. Immune system regulation by nutrition has uses in the clinical context, but it can also benefit... (Randomized Controlled Trial)
Randomized Controlled Trial
Prospective, Randomized, Double-Blind Parallel Group Nutritional Study to Evaluate the Effects of Routine Intake of Fresh vs. Pasteurized Yogurt on the Immune System in Healthy Adults.
The immune system is affected by the dietary products humans intake. Immune system regulation by nutrition has uses in the clinical context, but it can also benefit healthy populations by delaying or preventing the emergence of immune-mediated chronic illnesses. In this study, the purpose was to describe and compare the modulator effects on the immune system of the routine ingestion of fresh vs. pasteurized yogurt. A unicentral, prospective, randomized, double-blind, parallel group 8-week nutritional study was carried out comparing the ingestion of 125 g of the products in healthy adults three times a day. A complete battery of in vitro tests on the activity of the immune system, processes and phenomena was performed. Exclusive immune-modulatory effects of fresh yogurt with respect to base line were found in terms of increased systemic IgM (primary immune responses), increased synthesis of IFN-gamma upon stimulation (Th1) and increased peripheral T cells (mainly "naive" CD4s). In the three interventions, we observed an increased phagocytic activity and burst test in granulocytes, together with increased secretion of IL-6, IL-1 β and IL-8 (pro-inflammatory) and increased CD16 expression (FcR favoring phagocytosis) in granulocytes. Overall, it is concluded that regardless of bacteria being alive or thermally inactivated, yogurt has common effects on the innate system, but the presence of live bacteria is necessary to achieve a potentiating effect on the specific immune response.
Topics: Yogurt; Humans; Double-Blind Method; Adult; Male; Female; Prospective Studies; Pasteurization; Phagocytosis; Cytokines; Young Adult; Immunoglobulin M; Interferon-gamma; Middle Aged; Granulocytes; Immune System; Receptors, IgG
PubMed: 38931322
DOI: 10.3390/nu16121969 -
Microorganisms Jun 2024CRL1505 possesses immunomodulatory activities in the gastrointestinal and respiratory tracts when administered orally. Its adhesion to the intestinal mucosa does not...
CRL1505 possesses immunomodulatory activities in the gastrointestinal and respiratory tracts when administered orally. Its adhesion to the intestinal mucosa does not condition its beneficial effects. The intranasal administration of CRL1505 is more effective than the oral route at modulating immunity in the respiratory tract. Nonetheless, it has not yet been established whether the adherence of the CRL1505 strain to the respiratory mucosa is needed to provide the immune benefits to the host. In this study, we evaluated the role of adhesion to the respiratory mucosa of the mucus-binding factor (mbf) knock-out CRL1505 mutant ( CRL1505) in the context of a Toll-like receptor 3 (TLR3)-triggered innate immunity response. In vitro adhesion studies in porcine bronchial epitheliocytes (PBE cells) indicated that CRL1505 adhered weakly compared to the wild-type strain. However, in vivo studies in mice demonstrated that the CRL1505 also reduced lung damage and modulated cytokine production in the respiratory tract after the activation of TLR3 to a similar extent as the wild-type strain. In addition, the mutant and the wild-type strains modulated the production of cytokines and antiviral factors by alveolar macrophages in the same way. These results suggest that the Mbf protein is partially involved in the ability of CRL1505 to adhere to the respiratory epithelium, but the protein is not necessary for the CRL1505 strain to exert its immunomodulatory beneficial effects. These findings are a step forward in the understanding of molecular interactions that mediate the beneficial effects of nasally administered probiotics.
PubMed: 38930591
DOI: 10.3390/microorganisms12061209 -
Microorganisms May 2024Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health... (Review)
Review
Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.
PubMed: 38930417
DOI: 10.3390/microorganisms12061035 -
Antioxidants (Basel, Switzerland) May 2024Statins are 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors widely used in the treatment of hyperlipidemia. The inhibition of HMG-CoA reductase in...
Statins are 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors widely used in the treatment of hyperlipidemia. The inhibition of HMG-CoA reductase in the mevalonate pathway leads to the suppression of cell proliferation and induction of apoptosis. The cyclic GMP-AMP synthase (cGAS) stimulator of the interferon genes (STING) signaling pathway has been suggested to not only facilitate inflammatory responses and the production of type I interferons (IFN), but also activate other cellular processes, such as apoptosis. It has not been studied, however, whether cGAS-STING activation is involved in the apoptosis induced by statin treatment in human colorectal cancer cells. In this study, we reported that lovastatin impaired mitochondrial function, including the depolarization of mitochondrial membrane potential, reduction of oxygen consumption, mitochondrial DNA (mtDNA) integrity, and mtDNA abundance in human colorectal cancer HCT116 cells. The mitochondrial dysfunction markedly induced ROS production in mitochondria, whereas the defect in mitochondria respiration or depletion of mitochondria eliminated reactive oxygen species (ROS) production. The ROS-induced oxidative DNA damage by lovastatin treatment was attenuated by mitochondrial-targeted antioxidant mitoquinone (mitoQ). Upon DNA damage, mtDNA was released into the cytosol and bound to DNA sensor cGAS, thus activating the cGAS-STING signaling pathway to trigger a type I interferon response. This effect was not activated by nuclear DNA (nuDNA) or mitochondrial RNA, as the depletion of mitochondria compromised this effect, but not the knockdown of retinoic acid-inducible gene-1/melanoma differentiation-associated protein 5 (RIG-I/MDA5) adaptor or mitochondrial antiviral signaling protein (MAVS). Moreover, lovastatin-induced apoptosis was partly dependent on the cGAS-STING signaling pathway in HCT116 cells as the knockdown of cGAS or STING expression rescued cell viability and mitigated apoptosis. Similarly, the knockdown of cGAS or STING also attenuated the antitumor effect of lovastatin in the HCT116 xenograft model in vivo. Our findings suggest that lovastatin-induced apoptosis is at least partly mediated through the cGAS-STING signaling pathway by triggering mtDNA accumulation in the cytosol in human colorectal cancer HCT116 cells.
PubMed: 38929118
DOI: 10.3390/antiox13060679