Search Results (46)

Background/Objectives: HBeAg-positive chronic hepatitis B (CHB) patients with very high viral replication are often clinically considered a homogeneous, low-risk population. However, substantial biochemical, virological, and fibrosis-related heterogeneity may exist. This study aimed to characterize this heterogeneity in treatment-naive, HBeAg-positive CHB patients with ultra-high viral loads (HBV DNA ≥ 7.0 log₁₀ IU/mL). Furthermore, we sought to identify predictors of significant fibrosis and detect clinically relevant discordant phenotypes, such as silent disease progression despite normal alanine aminotransferase (ALT) levels. Methods: This single-center, retrospective, cross-sectional study analyzed consecutively screened eligible patients. A liver stiffness measurement (LSM, kPa) and controlled attenuation parameter (CAP, dB/m) were obtained via transient elastography. Significant fibrosis was defined as an LSM ≥ 7.0 kPa. Statistical evaluations included Spearman’s correlation, multivariable regression, ALT-LSM stratification, and K-means clustering. Results: Among 413 included patients, age and aspartate aminotransferase (AST) emerged as independent risk factors for significant fibrosis, whereas log10 HBV DNA and log10 HBsAg were independent negative predictors. Patients with HBsAg ≥ 25,000 IU/mL exhibited significantly lower LSM values than those with lower HBsAg levels. Notably, 18.4% of patients with strictly normal ALT (≤40 U/L) presented with an LSM ≥ 7.0 kPa, indicating silent progression. Cluster analysis further identified two distinct patient phenotypes characterized by differing age, ALT, viral load, and fibrosis profiles. Conclusions: An ultra-high viral load in HBeAg-positive CHB does not guarantee a uniformly benign clinical state. By quantifying biochemical, virological, and fibrotic heterogeneity, this study highlights a critical subgroup with silent fibrosis progression that risks being overlooked by ALT-based assessments alone. Full article

Viral helicases are conserved nucleic acid-dependent ATPases that drive genome replication, gene expression, and virion assembly, thereby playing a central role in viral replication and pathogenicity. Here, we discuss structural, biochemical, and virological data to compare helicase superfamilies, their conserved motifs, and translocation models that couple ATP hydrolysis to strand separation. We then analyze how viral helicases regulate replication fork progression, transcription and translation of viral RNAs, viral genome remodeling during replication, genome-packaging strategies, and evasion of innate immune signaling. Mechanistic examples from picornaviruses, flaviviruses, herpesviruses, and coronaviruses demonstrate how helicase architecture, substrate specificity, and cofactors control these activities. Finally, we discuss the opportunities and drawbacks of targeting viral helicases with antiviral drugs, recent screening and structure-guided discovery efforts, and emerging resistance mechanisms. Overall, this review provides a virus-centered synthesis of helicase structure, function, and inhibition that links conserved enzymatic activities to diverse infection outcomes and antiviral strategies across viral families. Full article

Chronic hepatitis B remains difficult to cure because viral persistence is maintained within hepatocytes through covalently closed circular DNA and integrated viral sequences that continue to drive antigen production even when viral replication is effectively suppressed. Although current antiviral therapies improve clinical outcomes and slow disease progression, they rarely achieve a durable functional cure, defined as sustained loss of hepatitis B surface antigen (HBsAg), with or without anti-HBs seroconversion. This limitation has shifted attention toward therapeutic strategies that depend on precise and reliable drug delivery to the liver. Several recent reviews have focused on antiviral mechanisms or immune modulation. However, the specific contribution of drug delivery to therapeutic success has not been systematically addressed. This review examines hepatocyte-targeted drug delivery as a central determinant of success for emerging hepatitis B therapies. Rather than cataloging individual therapeutic agents, this review adopts a delivery-centered framework that links viral persistence biology with translational feasibility across therapeutic classes. Recent advances in ligand-mediated hepatocyte targeting have demonstrated consistent liver specificity and clinical feasibility, enabling meaningful reductions in viral transcripts and antigens. At the same time, we discuss why more complex delivery platforms continue to face challenges related to intracellular access, immunogenicity, scalability, and safety during repeated dosing, particularly for strategies intended to act within the nucleus. Translational and clinical considerations, including differences between experimental models and human infection, manufacturing and regulatory constraints, and the demands of long-term treatment, are also addressed. Overall, this review supports a pragmatic path toward functional cure based on rational combination therapies, coordinated delivery strategies, and patient-tailored approaches, with delivery science serving as the critical link between biological insight and durable clinical benefit. Full article

Curcumin, the major polyphenolic constituent of Curcuma longa, has been widely investigated as a hepatoprotective adjunct due to its antioxidant and immunomodulatory properties. This review evaluates the relevance of curcumin for the prevention and management of liver dysfunction and hepatitis in pigs by synthesizing available porcine evidence and integrating mechanistic insights from translational liver injury models where pig-specific data remain limited. Across experimental hepatic injury contexts, curcumin administration is most consistently associated with reduced biochemical and structural indicators of hepatocellular damage, including decreased aminotransferase activity, attenuation of lipid peroxidation, and enhancement of endogenous antioxidant defenses. These effects are mechanistically linked to suppression of pro-inflammatory signaling pathways, particularly NF-κB-related transcriptional activity and inflammasome-associated responses, together with reduced expression of key cytokines such as TNF-α, IL-1β, and IL-6. Concurrent activation of Nrf2-centered cytoprotective pathways and induction of phase II antioxidant enzymes (including HO-1, GST, and NQO1) appear to constitute a conserved axis supporting hepatic oxidative stress resilience. In swine-relevant infectious settings, available data further support antiviral activity against selected porcine pathogens, including classical swine fever virus and porcine reproductive and respiratory syndrome virus, potentially mediated through interference with lipid-dependent stages of viral replication and modulation of Kupffer cell activation. Although combination strategies with established hepatoprotective approaches are conceptually attractive, current synergy evidence remains heterogeneous and largely extrapolated. Overall, curcumin represents a plausible adjunct candidate for supporting porcine liver health; however, translation into practice will depend on resolving formulation-dependent bioavailability constraints and strengthening the pig-specific evidence base. Full article

Interferon-stimulated genes (ISGs) are classically recognized for their direct antiviral functions, such as viral genome degradation or replication blockade. However, emerging evidence reveals that ISGs orchestrate a broader landscape of host defense by rewiring cellular metabolism. These mechanisms are still not fully understood in the context of antiviral immunity. This review synthesizes recent advances in understanding how ISGs modulate metabolic pathways (e.g., glycolysis, lipid metabolism, amino acids, and nucleotide metabolism) to create an antiviral cellular environment. However, viruses have developed strategies to evade or counteract ISG-encoded proteins, and some even hijack certain ISGs to their advantage. Therefore, we further explore how viruses subvert these ISG-driven metabolic to evade host defenses. Overall, we summarize the current state of knowledge on the interactions between viruses and ISGs and propose that ISGs act as “protective” or “pathogenic” regulators at the dimensions of metabolism, offering new perspectives for targeting host-centered pathways to combat viral infections. Full article

Background and Objectives: Antiretroviral therapy used during pregnancy in HIV infected women effectively reduces vertical transmission, though concerns about potential adverse newborn outcomes persists. This study focused on prematurity and low birth weight in antiretroviral HIV-exposed children in two major Romanian centers, Bucharest and Constanța, in the context of free access to antiretroviral treatment for pregnant women in Romania since 2001. Materials and Methods: A retrospective observational study was performed including couples of HIV-infected women and their live singleton newborns from 2006 and 2012. Preterm delivery was defined as birth before week 37 and low birth weight was defined as birth weight less than 2500 g in full-term babies. Results: A total number of 352 children and 313 women were enrolled. Mean maternal age at delivery was 23.1 years. Mean newborn birth weight was 2726 g. In the children group, 191 (54.2%) were boys, and the rate of HIV transmission was 13.9%. The prematurity rate was 21.5% and low birth weight rate was 25.56%. Preterm birth was associated with high HIV RNA in the third trimester, HIV-positive final status in infants, and vaginal delivery. Low birth weight was associated with lack of antiretroviral treatment during pregnancy and HIV-positive status in infants. No association was found between prematurity and low birth weight in full-term newborns and exposure to any antiretroviral class, any specific antiviral drug, or with any number of maternal regimens, duration of antiretroviral treatment prior to conception, or maternal exposure during puberty. Conclusions: In our study, preterm birth was significantly associated with HIV vertical transmission in newborns and with exposure to high maternal viral replication during the last trimester of pregnancy. Low birth weight in full-term babies was significantly associated with lack of antiretroviral exposure in utero in our analysis. Full article

Background: Heart failure (HF) remains a major global health challenge, with orthotopic heart transplantation (OHT) serving as the gold-standard therapy for end-stage disease. Chronic immunosuppression required to prevent graft rejection increases the risk of infections and malignancies. The COVID-19 pandemic underscored the particular vulnerability of transplant recipients to severe SARS-CoV-2 infection. Specific immunosuppressive agents used in OHT patients may differentially affect SARS-CoV-2 infection. In particular, mTOR inhibitors may modulate viral replication and immune responses, potentially influencing disease severity. Objectives: This study evaluated the impact of immunosuppressive regimens—particularly mTOR inhibitors—on COVID-19 outcomes in heart transplant recipients, comparing mTOR-based therapy (with or without calcineurin inhibitors, CNIs) to non-mTOR-based regimens. Methods: This single-center retrospective observational study included 556 orthotopic heart transplant recipients (76.3% male; median age, 58 years) followed from March 2020 to March 2024. To compare patients receiving mTOR inhibitors with similar non-mTOR recipients, 3:1 propensity score matching was performed based on age, sex, and body mass index. Among the study population, 88 patients (15.8%) received mTOR inhibitors (everolimus or sirolimus), of whom 66 were concomitantly treated with calcineurin inhibitors and 22 without. Data were obtained from the National Health Fund database and clinical follow-ups. Results: Overall mortality was 13.5%, and COVID-19-related mortality 3.2%. COVID-19 incidence was 33% in the mTOR group versus 36.7% in the non-mTOR group (p = 0.52). Hospitalization rates were 3.4% and 6.4% (p = 0.29), respectively. All-cause mortality was higher among mTOR users (21.6% vs. 11.7%, p = 0.02), especially in the mTOR+CNI subgroup. Notably, no COVID-19-related deaths occurred in the mTOR CNI-free group. Conclusions: mTOR-based immunosuppression was non-inferior to standard therapy for COVID-19 outcomes. The absence of COVID-19-related deaths in patients on mTOR CNI-free regimens suggests potential protective effects that merit further investigation. Full article

HIV causes intense polyclonal activation of B cells, resulting in increased numbers of spontaneously antibody-secreting cells in the circulation and hypergammaglobulinemia. It is accompanied by significant perturbations in various B cell subsets, such as increased frequencies of immature/transitional B cells, activated memory B cells, atypical memory B cells, short-lived plasmablasts and regulatory B cells, as well as by decreased frequencies of resting memory and resting naïve B cells. Furthermore, both memory and antigen-inexperienced naïve B cells show exhausted and immune-senescent phenotypes. HIV also drives the expansion and functional impairment of CD4⁺ T follicular helper cells, which provide help to B cells, crucial for the generation of germinal center reactions and production of long-lived plasma and memory B cells. By suppressing viral replication, anti-retroviral therapy reverses the virus-induced perturbations and functional defects, albeit inadequately. Due to HIV’s lingering impact on B cells, immune senescence and residual chronic inflammation, people with HIV (PWH), especially immune non-responders, are immunocompromised and mount suboptimal antibody responses to vaccination for SARS-CoV-2. Here, we review how functionally and phenotypically distinct B cell subsets are induced in response to a vaccine and an infection and how HIV infection and anti-retroviral therapy (ART) impact them. We also review the role played by HIV-induced defects and perturbations in B cells in the induction of humoral immune responses to currently used anti-SARS-CoV-2 vaccines in PWH on ART. We also outline different strategies that could potentially enhance the vaccine-induced antibody responses in PWH. The review will provide guidance and impetus for further research to improve the immunogenicity of these vaccines in this human population. Full article

Human coronavirus 229E (HCoV-229E) is an alpha coronavirus that infects humans and bats. In common with all positive-strand RNA viruses, 229E infection causes rearrangements of the host’s intracellular membranes to form replication organelles, a highly conserved and vital step in the viral replication cycle. Here, we investigated the role of the ESCRT protein VPS4A in 229E infection. We found that functional VPS4A was required for the formation of replication organelles and localizing viral RNA to these structures in host cells to facilitate viral genome replication. We validated this effect using small molecule inhibitors to VPS4A, significantly reducing virus replication. We also showed that other ESCRTS, like CHMP4B, were required for the virus replication step, whereas VPS37A was involved in the post-replication stages. The absence of a functional VPS4A prevented the remodeling of membranes to form viral replication centers and, therefore, exposed the viral RNA, triggering an inflammatory immune response as indicated by elevated levels of IL-6. Interestingly, we observed the role of VPS4A to be similar for the OC43 coronavirus, indicating it could be conserved across all four coronavirus genera, including SARS-CoV-2. Understanding more about the replication of coronaviruses is imperative to finding more effective ways to control them. Full article

Proteases represent common targets in combating infectious diseases, including COVID-19. The 3-chymotrypsin-like protease (3CLpro) is a validated molecular target for COVID-19, and it is key for developing potent and selective inhibitors for inhibiting viral replication of SARS-CoV-2. In this review, we discuss structural relationships and diverse subsites of 3CLpro, shedding light on the pivotal role of dimerization and active site architecture in substrate recognition and catalysis. Our analysis of bioinformatics and other published studies motivated us to investigate a novel catalytic mechanism for the SARS-CoV-2 polyprotein cleavage by 3CLpro, centering on the triad mechanism involving His41-Cys145-Asp187 and its indispensable role in viral replication. Our hypothesis is that Asp187 may participate in modulating the pK_a of the His41, in which catalytic histidine may act as an acid and/or a base in the catalytic mechanism. Recognizing Asp187 as a crucial component in the catalytic process underscores its significance as a fundamental pharmacophoric element in drug design. Next, we provide an overview of both covalent and non-covalent inhibitors, elucidating advancements in drug development observed in preclinical and clinical trials. By highlighting various chemical classes and their pharmacokinetic profiles, our review aims to guide future research directions toward the development of highly selective inhibitors, underscore the significance of 3CLpro as a validated therapeutic target, and propel the progression of drug candidates through preclinical and clinical phases. Full article

Based on the assumption that the process of understanding is partly narrative, this study explores the potential benefits and limitations of using narrative writing in biology education. We investigate what contribution a student-centered narrative intervention can make to the conceptual understanding of protein biosynthesis in the context of viral infections and virus replication. After a teaching sequence on this topic, 68 secondary school students (M = 15.7 years, SD = 0.57 years) explained virus replication in a written text. One subsample (n = 46) was instructed to write a narrative text, while the other one (n = 22) was asked to write an expository (non-fictional) text. Our data analysis encompassed an analysis of the structural narrativity in the student texts, as well as a concept-related rating of the level of scientific correctness in three categories. A post-test questionnaire (35 items) was used to depict the learners’ viewpoints on their respective text production and the learning process that they experienced. Our findings indicate that most learners actually produced the text type they were supposed to, with exceptions in both sub-samples. As to the level of concept-related scientific correctness, we found no major differences between the two interventions. However, for two concepts, compartmentalization and levels of organization, the data indicate the significant advantage of the narrative intervention. We conclude from our results that to some extent, the effective learning properties of narrative texts, derived from the theoretical foundations, could indeed successfully be demonstrated in the field of virus replication. However, narrative text production is not equally beneficial for all aspects of the biological topic, and it also poses specific problems for some learners. Full article

SARS-CoV-2 infection remains a global burden. Despite intensive research, the mechanism and dynamics of early viral replication are not completely understood, such as the kinetics of the formation of genomic RNA (gRNA), sub-genomic RNA (sgRNA), and replication centers/organelles (ROs). We employed single-molecule RNA-fluorescence in situ hybridization (smRNA-FISH) to simultaneously detect viral gRNA and sgRNA and immunofluorescence to detect nsp3 protein, a marker for the formation of RO, and carried out a time-course analysis. We found that single molecules of gRNA are visible within the cytoplasm at 30 min post infection (p.i.). Starting from 2 h p.i., most of the viral RNA existed in clusters/speckles, some of which were surrounded by single molecules of sgRNA. These speckles associated with nsp3 protein starting at 3 h p.i., indicating that these were precursors to ROs. Furthermore, RNA replication was asynchronous, as cells with RNA at all stages of replication were found at any given time point. Our probes detected the SARS-CoV-2 variants of concern, and also suggested that the BA.1 strain exhibited a slower rate of replication kinetics than the WA1 strain. Our results provide insights into the kinetics of SARS-CoV-2 early post-entry events, which will facilitate identification of new therapeutic targets for early-stage replication to combat COVID-19. Full article

The recent Mpox virus (MPV) outbreak in Europe and North America, primarily among men who have sex with men (MSM), raised concerns about various transmission sources. We examined patients with Mpox from an urban STI center in Lombardy, Italy, between May and August 2022. Demographic, transmission, and clinical data were collected using a standardized form. Initial and subsequent tests were conducted using the RealStar Orthopoxvirus PCR Kit 1.0 (Altona Diagnostics, Hamburg, Germany) for skin lesions and oropharyngeal swabs. A total of 15 patients were recruited, all MSM, with 40% being HIV-positive. Almost all reported recent unprotected sexual activity. Oropharyngeal symptoms were observed in a minority, and oral cavity lesions were present in 20% of cases. MPV DNA was detected in skin lesions of 93% of patients and in oropharyngeal swabs of 87%. Skin samples exhibited a higher viral load than pharyngeal samples, with the latter persisting longer. Prospective follow-up of 11 individuals revealed an average pharyngeal persistence of 5.3 days beyond skin lesion clearance, reaching up to 80 days in an immunosuppressed case. Our findings indicate that MPV replication can persist in the pharynx asymptomatically and for an extended period. Full article

In light of the COVID-19 global pandemic caused by SARS-CoV-2, ongoing research has centered on minimizing viral spread either by stopping viral entry or inhibiting viral replication. Repurposing antiviral drugs, typically nucleoside analogs, has proven successful at inhibiting virus replication. This review summarizes current information regarding coronavirus classification and characterization and presents the broad clinical consequences of SARS-CoV-2 activation of the angiotensin-converting enzyme 2 (ACE2) receptor expressed in different human cell types. It provides publicly available knowledge on the chemical nature of proposed therapeutics and their target biomolecules to assist in the identification of potentially new drugs for the treatment of SARS-CoV-2 infection. Full article

Minute Virus of Mice (MVM) is an autonomous parvovirus of the Parvoviridae family that replicates in mouse cells and transformed human cells. MVM genomes localize to cellular sites of DNA damage with the help of their essential non-structural phosphoprotein NS1 to establish viral replication centers. MVM replication induces a cellular DNA damage response that is mediated by signaling through the ATM kinase pathway, while inhibiting induction of the ATR kinase signaling pathway. However, the cellular signals regulating virus localization to cellular DNA damage response sites has remained unknown. Using chemical inhibitors to DNA damage response proteins, we have discovered that NS1 localization to cellular DDR sites is independent of ATM or DNA-PK signaling but is dependent on ATR signaling. Pulsing cells with an ATR inhibitor after S-phase entry leads to attenuated MVM replication. These observations suggest that the initial localization of MVM to cellular DDR sites depends on ATR signaling before it is inactivated by vigorous virus replication. Full article