Search Results (210)

Dengue virus (DENV) and SARS-CoV-2 are emerging viral pathogens that share overlapping clinical features, including fever, fatigue, and respiratory symptoms, complicating differential diagnosis in endemic regions. Their co-circulation has increased the risk of co-infections, which may result in unpredictable disease progression, increased morbidity, and mortality. This overlap presents a significant challenge in managing outbreaks, as both viruses pose a major public health threat. Vaccines and direct-acting antivirals may be rendered ineffective by viral mutations, making it difficult to address evolving strains. Host-directed antivirals offer a promising alternative, potentially maintaining efficacy against a multitude of variants. Both DENV and SARS-CoV-2 rely on host proteases for viral maturation and entry, with furin playing a crucial role in viral glycoprotein cleavage. In DENV, furin cleaves the prM protein, facilitating virion maturation, while in SARS-CoV-2, the polybasic furin cleavage site in the spike protein enhances viral entry. This makes furin a compelling pan-viral target, where inhibiting furin could reduce viral fitness without relying on viral mutations. This review highlights the therapeutic rationale for targeting furin and discusses luteolin, a furin inhibitor showing antiviral activity against both viruses. Furin-targeted therapies may offer a durable antiviral strategy effective across DENV serotypes, SARS-CoV-2 variants, and co-infection settings. Full article

Postprandial variability in glucose and protein levels is one of the elements of insulin resistance (IR) and prediabetes, which is an area precursor to type 2 diabetes mellitus (DM). The objective of the study was a comprehensive proteomic analysis according to glucose tolerance in the general population who did not self-report DM or other diseases. We used Olink^® Reveal, a novel, high-throughput platform by Olink Proteomics based on their Proximity Extension Assay (PEA), to identify levels of 1034 circulating proteins in small volumes (4 µL) of plasma samples. The study enrolled 508 participants (mean age 52 ± 10.5 years, 47.2% men) from the population-based study, Bialystok PLUS Polish Longitudinal University Study. The study population was categorized according to glucose metabolism in comparison to impaired fasting blood glucose (IFG), impaired glucose tolerance (IGT), and newly diagnosed DM. Analysis of variance (ANOVA) adjusted for age, weight, fat mass, lean mass, and body mass index (BMI), identified 19 proteins significantly associated with categories of glucose tolerance. Of the five markers with the greatest ability to distinguish newly diagnosed diabetes from non-diabetic participants, paralemmin 2 performed best (AUC = 0.81; 77% sensitivity, 75% specificity), whereas furin was the most accurate for detecting any abnormal glucose regulation (AUC = 0.69). A linear regression model adjusted for the same confounding factors showed statistically significant associations between Hb_A1c levels and 37 proteins. Our findings highlight multiple proteins with significantly different levels across categories of glucose tolerance, especially between the healthy controls and the group with newly diagnosed DM. The consistent patterns of protein level differences, independent of body composition, suggest potential involvement in the progression of glucose metabolism disturbances and provide unique insights into pathomechanisms. These findings identify PALM2, FURIN, PDZK1, ACAA1, and IL18R1 as potential biomarkers of early dysglycemia. Full article

Background: Aging is accompanied by a progressive decline in skeletal muscle regeneration, largely due to impaired myogenic differentiation. The proprotein convertase FURIN is a key protease responsible for activating several signaling molecules, including precursors of NOTCH receptors, which regulate cell fate and differentiation. In this study, we investigated whether age-associated downregulation of FURIN contributes to impaired NOTCH2/3 signaling and myogenic function. Methods: An initial bioinformatics analysis of public scRNA-seq data from Genotype-Tissue Expression (GTEx) project indicated age-related expression of genes in the NOTCH signaling pathway. In vitro verification used early- and late-passage C2C12 myoblasts as a model of muscle cell aging to compare the expression of these genes. Late-passage C2C12 cells were transiently transfected with FURIN plasmid to assess restoration of differentiation potential, quantified by the fusion index, myogenic marker expression, and morphology. Results: Expression of FURIN, NOTCH2 and NOTCH3 was negatively correlated with age, whereas GZMB increased with age in GTEx dataset. Late-passage myoblasts exhibited impaired myotube formation, reflecting age-associated loss of myogenic capacity. Restoration of FURIN expression in aged myoblasts was associated with reduced GZMB levels, increased expression of embryonic myosin heavy chain IGF1, and partial recovery of myogenic differentiation and myotube formation. Conclusions: These findings suggest that age-associated loss of FURIN contributes to impaired NOTCH2/3 pathways and myogenic dysfunction. Overexpression of FURIN partially rescues the myogenic phenotype and increases expression of early myogenic markers in aged cells, identifying FURIN as a potential regulator of muscle regenerative capacity during aging. We suggest FURIN as a promising candidate target for further investigation into the mechanisms driving aging or age-related decline. Full article

Pregnancy represents a distinct immunological and physiological state that modifies maternal susceptibility to SARS-CoV-2 and influences the clinical and biological course of COVID-19. Accumulating evidence indicates that the interaction between viral entry determinants, gestation-specific immune modulation, placental endocrine–angiogenic pathways, and systemic inflammatory responses underlies the characteristic manifestations of SARS-CoV-2 infection during pregnancy. This review consolidates current understanding of SARS-CoV-2 viral structure, receptor biology, and the gestational regulation of key entry cofactors, including ACE2, TMPRSS2, NRP1, CTSL and FURIN, within reproductive and placental tissues. The review further integrates documented mechanisms of cytokine-mediated immune dysregulation, endothelial injury, thrombo-inflammation, and steroidogenic alteration observed in affected pregnancies, and examines their contribution to placental malperfusion, preeclampsia-like presentations, fetal growth abnormalities and preterm birth. Published molecular and computational studies characterising trophoblast antiviral defenses, receptor expression patterns, and structural determinants of Spike–ACE2 affinity are synthesised to contextualise the biological basis of placental susceptibility and the rarity of confirmed transplacental transmission. Current evidence on maternal clinical outcomes, fetal and neonatal consequences, vaccination efficacy, therapeutic considerations and contemporary management guidelines is also critically reviewed. By integrating molecular, immunological, pathological and clinical insights, this article provides a comprehensive framework for understanding the interaction between SARS-CoV-2 infection and pregnancy-specific physiology, with implications for risk assessment, preventive strategies and maternal–fetal care. Full article

Background/Objectives: Olfactory dysfunction and dysgeusia are common neurosensory manifestations of Coronavirus Disease 2019 (COVID-19), affecting approximately 60% of patients. These symptoms have been mechanistically linked to receptors involved in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) cell entry, including angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), furin, and neuropilin-1 (NRP1), which are highly expressed in the olfactory epithelium. Nevertheless, clinical evidence supporting a direct association between receptor expression and sensory impairment remains inconsistent. Methods: We conducted a multicenter, observational, cross-sectional study including 104 adults with polymerase chain reaction–confirmed SARS-CoV-2 infection during the first and second pandemic waves. Approximately 75 days after diagnosis, nasal and/or pharyngeal samples were obtained to quantify gene expression levels of ACE2, TMPRSS2, furin, and NRP1 using quantitative polymerase chain reaction. Olfactory dysfunction and dysgeusia were recorded as dichotomous variables. Logistic regression analyses were performed with adjustment for age, sex, and race, considering receptor expression as continuous variables and as tertiles. Missing data were addressed using multiple imputation methods. Results: Olfactory dysfunction was reported by 37.5% of participants, and dysgeusia by 36.5%. No statistically significant associations were observed between baseline expression levels of ACE2, TMPRSS2, furin, or NRP1 and the presence of olfactory dysfunction or dysgeusia in either adjusted continuous or categorical models. Although these associations did not reach statistical significance, higher ACE2 and furin expression showed a nonsignificant trend toward an increased probability of sensory alterations, whereas intermediate NRP1 levels were associated with lower disease severity. Conclusions: COVID-19-related olfactory dysfunction and dysgeusia do not appear to be directly determined by isolated baseline expression of SARS-CoV-2 entry receptors. These findings support a multifactorial and dynamic pathophysiological model involving temporal receptor regulation, inflammatory processes, and host-related factors, highlighting the need for longitudinal and interventional studies. Full article

Serine proteases are a class of enzymes that orchestrate an immune response. These proteases can be hijacked by viruses to facilitate entry and spread, while simultaneously supporting the innate immune system in neutralizing pathogens. This review highlights the dual roles of exogenous serine proteases, emphasizing neutrophil serine proteases (NSPs) that facilitate viral entry and promote disease progression while also contributing to antiviral defense by degrading viral glycoproteins. Additionally, the potential to modulate serine protease activity to boost host defenses will be discussed, offering both significant challenges and new opportunities for therapeutic intervention. Full article

A 19 nt fragment that spans the SARS-CoV-2 furin cleavage site (FCS) is identical to the reverse complement of a proprietary human DNA repair gene sequence. Rather than interpreting this overlap as evidence of a laboratory event, this article uses it as a theoretical springboard to explore underappreciated biorisk concerns, specifically in the context of cancer research. Although they are RNA viruses, coronaviruses are capable of hijacking host DNA damage response (DDR) pathways, exploiting nuclear functions to enhance replication and evade innate immunity. Under selective pressures (antivirals, DDR antagonists, or large-scale siRNA libraries designed to silence critical host genes), escape mutants may arise with fitness advantages. Parallel observations involving in vivo RNA interference via chimeric viruses lend plausibility to some of the key aspects underlying unappreciated biorisks. The mechanistic insights that incorporate DNA repair mechanisms, CoVs in the nucleus, specifics of viruses in cancer research, anticancer drugs, automated gene silencing experiments, and gene sequence overlaps identify gaps in biorisk policies, even those unaccounted for by the potent “Sequences of Concern” paradigm. Key concerning attributes, including genome multifunctionality, such as NLS/FCS in SARS-CoV-2, antisense sequences, and their combination, are further described in more general terms. The article concludes with recommendations pairing modern technical safeguards with enduring ethical principles. Full article

Objective: To investigate the mechanism by which sphingosine-1-phosphatase 2 (SGPP2) modulates endoplasmic reticulum stress (ERS) through the SIRT1/AMPK pathway to improve ischemic cardiomyopathy-induced chronic heart failure (IHF). Methods: Key genes of IHF and ERS were identified through bioinformatics analysis, and significantly associated pathways of the key genes were obtained via single-gene enrichment analysis. In vivo, IHF was induced in Sprague–Dawley (male) rats via ligation of the left anterior descending coronary artery, with cardiac function examined through echocardiography. Myocardial tissue injury and fibrosis were evaluated utilizing hematoxylin-eosin, Masson, and TUNEL staining. Serum levels of NT-proBNP and cTnT were measured via ELISA. SGPP2 protein expression was assessed via immunohistochemistry and Western blotting (WB). In vitro, neonatal rat cardiomyocytes (NRCMs) were isolated and underwent oxygen-glucose deprivation (OGD) to establish an IHF model. SGPP2-overexpressing NRCMs were constructed and treated with the ERS inducer tunicamycin (Tu) or the SIRT1 inhibitor EX527. Cell injury was evaluated using Cell Counting Kit-8 and lactate dehydrogenase release assays, as well as flow cytometry. Endoplasmic reticulum structure was examined by transmission electron microscopy. The endoplasmic reticulum was labeled with the ER-Tracker Red molecular probe. WB was utilized to detect the expression of apoptosis- and ERS-linked proteins, and the activity of the SIRT1/AMPK signaling pathway. Results: Six key genes (CTSK, FURIN, SLC2A1, RSAD2, SGPP2, and STAT3) were identified through bioinformatics analysis, with SGPP2 showing the most significant differential expression. Additionally, SGPP2 was found to be downregulated in IHF. Single-gene enrichment analysis showed that SGPP2 exhibited a significant association with the AMPK signaling pathway. Animal experiments demonstrated that rats with IHF exhibited significantly impaired cardiac function, marked myocardial tissue injury and fibrosis, ERS in myocardial tissue, lowered SGPP2 expression, and decreased SIRT1/AMPK signaling pathway activity. In vitro experiments confirmed that SGPP2 overexpression alleviated OGD-induced cardiomyocyte injury by inhibiting ERS and simultaneously activating the SIRT1/AMPK signaling pathway. Rescue experiments further demonstrated that both Tu and EX527 significantly promoted ERS and cellular injury, thereby counteracting the protective effects of SGPP2. Conclusions: SGPP2 alleviates IHF by inhibiting ERS modulated by the SIRT1/AMPK pathway. Full article

Colorectal cancer (CRC) remains one of the most lethal malignancies worldwide, with 5-fluorouracil (5-Fu) as a mainstay of treatment. However, intrinsic and acquired resistance to 5-Fu significantly limits therapeutic success. Furin, a proprotein convertase, is known to activate multiple substrates critical for tumor progression, yet its precise role in CRC remains unclear. In this study, we examined furin expression in a large cohort of CRC patient samples and performed functional analyses in CRC cell lines and xenograft models. Furin overexpression was seen in 46.9% (530/1131) of CRC cases and was significantly correlated with TGF-β and ERK1/2 activation. In vitro, induced furin overexpression enhanced proliferation and clonogenicity, accompanied by upregulation of TGF-β and ERK1/2 phosphorylation, whereas furin silencing attenuated tumor cell growth and TGF-β/ERK signaling. Manipulation of TGF-β revealed a reciprocal regulatory loop, whereby TGF-β upregulated furin expression, establishing a feed-forward circuit that augmented ERK signaling and tumor growth. Notably, 5-Fu-resistant CRC cell lines displayed elevated furin, TGF-β, and phospho-ERK1/2, while furin knockdown restored drug sensitivity. In vivo, furin overexpression enhanced tumor growth in xenografts, whereas its depletion markedly reduced tumor burden and TGF-β/ERK signaling activity. Collectively, these findings demonstrate that furin promotes CRC progression and chemoresistance through a positive feedback loop with TGF-β that sustains ERK activation. Targeting furin, alone or in combination with TGF-β/ERK inhibitors, may offer a promising therapeutic strategy for CRC. Full article

Irisin is a myokine secreted by muscle in response to exercise. It is derived from a transmembrane protein called fibronectin type III domain-containing protein 5 (FNDC5). The Fndc5 gene is expressed in several tissues, including skeletal muscle, brain, adipose tissue, heart, kidney, and lung. Irisin is cleaved from FNDC5 protein by the enzyme furin and released into circulation. In addition to exercise, several drugs have been shown to increase the production of irisin. Administration of exogenous irisin mimics the beneficial actions of exercise. Irisin can cross the blood–brain barrier and exert neuroprotective actions in the brain. It has been shown to reverse Alzheimer’s pathologies in clinical and animal studies. Irisin also exerts protective effects against obesity, diabetes, and cardiovascular disease, diseases that often coexist with aging AD patients. Multiple approaches have been taken to suggest that exercise may act through irisin. Studies have provided direct evidence linking the two using Fndc5 gene deletion and irisin antibodies. Irisin binds to αVβ1/β5 integrins to mediate the activation of integrin-FAK pathways. While exercise as a lifestyle modification for healthy aging is well recognized, it may present limitations in some aging populations, especially those with disease conditions, including Parkinson’s disease. Administration of exogenous irisin or small molecules that increase the expression of endogenous irisin or facilitate its actions are some alternate approaches that can mimic the beneficial actions of exercise. This review discusses the therapeutic potential of irisin in the treatment of neurodegenerative and other aging-associated diseases. Full article

Furin, a calcium-dependent serine endoprotease of the proprotein convertase family, plays a pivotal role in both physiological homeostasis and viral pathogenesis. By cleaving polybasic motifs within viral glycoproteins, furin enables the maturation of structural proteins essential for viral entry, fusion, and replication. This mechanism has been documented across a broad spectrum of human pathogens, including SARS-CoV-2, influenza virus, human immunodeficiency virus, human papilloma virus, hepatitis B virus, flaviviruses, herpesviruses, and paramyxoviruses, highlighting furin as a conserved molecular hub in host–virus interactions. Genetic variability within the FURIN gene further modulates infection outcomes. Several single-nucleotide polymorphisms (SNPs), such as rs6226 and rs1981458, are associated with altered COVID-19 severity, whereas variants like rs17514846 confer protection against human papilloma virus infection. Conversely, mutations predicted to reduce enzymatic activity have been linked to attenuated SARS-CoV-2 pathogenesis in certain populations. These findings underscore the importance of considering population genetics when evaluating viral susceptibility and disease progression. Despite advances, unresolved questions remain regarding furin’s non-canonical roles in viral life cycles, tissue-specific regulation, and interactions with other host proteases and immune modulators. Targeted inhibition of furin and related convertases represents a promising avenue for broad-spectrum antiviral interventions. Collectively, current evidence positions furin as a central node at the intersection of viral pathogenesis, host genetic variability, and translational therapeutic potential. Full article

The undifferentiated nasopharyngeal cancer (NPC) is a multifactorial disease mainly due to Epstein-Barr Virus (EBV) infection. The transmembrane tyrosine kinase ‘EphA2’ and the protease ‘Furin’ are implicated in the EBV entry into epithelial cells and other physiological processes. To gain insights into the association of single-nucleotide polymorphisms (SNPs) rs4702 and rs6603883 (FURIN and EPHA2 genes, respectively) with the risk and prognosis of the NPC, the genotypes of 471 individuals (228 cases and 243 controls) were assessed alongside risk cofactors (sex, tobacco, alcohol, occupation, and recurrent Ear, Nose and Throat infections) and prognosis cofactors (Tumor stage, local invasion, lymph node involvement, and metastasis) using multivariable logistic regression. We found that only the rs4702 AG/GG genotypes were statistically significantly associated with a reduced risk of cancer, both in the overall population and in men (approximately 50% reduction). The rs4702 GG genotype was also associated with a low frequency of local tumor invasion in the whole population (OR = 0.382, p = 0.017, co-dominant model, and OR = 0.409, p = 0.02, recessive model), but heterozygous women were associated with a higher lymph node involvement (OR = 3.53, p = 0.031, co-dominant model, and OR = 3.62, p = 0.02, overdominant model). The rs6603883 GG genotype was associated, in the dominant model, with distant metastasis in the whole population (OR = 2.5, p = 0.024), with advanced clinical stage in men (OR = 2.22, p = 0.034), and with advanced clinical stage and distant metastasis in patients under 49 years (OR = 3.13, p = 0.009, and OR = 5.15, p = 0.011, respectively). Additionally, men having the rs6603883 GA genotype were associated with lymph node invasion (OR = 2.22, p = 0.027, overdominant model). Our study is the first to demonstrate that FURIN and EPHA2 germline gene polymorphisms are associated with NPC risk (for rs4702) and prognosis (for both rs4702 and rs6603883), with sex-specific differences. These results need to be replicated and further investigated in other populations. Full article

This study aimed to evaluate the inhibitory potential of phenolic-rich extracts from selected medicinal plants belonging to the Lamiaceae and Asteraceae families against the furin protease enzyme, a key target in viral and oncogenic pathways. Extracts of Origanum vulgare, Thymus vulgaris, Mentha piperita, Mentha spicata, Salvia officinalis, and Silybum marianum were prepared using hexane, chloroform, and ethyl acetate. Phenolic compounds were quantified using High-Performance Liquid Chromatography (HPLC). Furin inhibition was assessed spectrophotometrically and analyzed statistically with multivariate approaches. The chloroform extract of Origanum vulgare exhibited 97.44 ± 0.12% inhibition, while the ethyl acetate extract of Mentha spicata showed 97.44 ± 0.08% inhibition. Epicatechin and rutin displayed significant synergistic effects, while naringenin negatively affected inhibition (p < 0.05). Solvent polarity significantly influenced phenolic diversity and biological activity, with ternary combinations showing 33% higher inhibition than single compounds. These findings highlight phenolic blends as promising natural furin inhibitors, with chloroform being optimal for broad-spectrum extraction. Full article

CD9 protein belongs to a family of proteins called tetraspanins, so named for their four-transmembrane-spanning architectures. These proteins are located in domains in the plasmatic membrane, called tetraspanin-enriched microdomains (TEMs). Several proteases and cellular receptors for virus entry cluster into TEMs, suggesting that TEMs are preferred virus entry portals. Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein mediates virus attachment and entry into cells by binding to human angiotensin-converting enzyme 2 (ACE-2). In addition, the secretory, type-I membrane-bound SARS-CoV-2 S protein is synthesized as a precursor (proS) that undergoes posttranslational cleavages by host cell proteases, such as furin and TMPRSS2. Moreover, it has been shown that neuropilin-1 (NRP1), which is known to bind furin-cleaved substrates, potentiates SARS-CoV-2 infectivity. Our results indicate that CD9 facilitates SARS-CoV-2 infection. In addition, we show how knocking out CD9 leads to a decrease in the expression of NRP1, a protein that improves SARS-CoV-2 infection. Furthermore, we show that CD9 colocalizes with ACE-2, NRP1, furin, and TMPRSS2 at the plasma membrane; that the absence of CD9 decreases the expression of these proteins on the plasma membrane CD9-enriched microdomains, and that CD9 interacts with ACE2. In conclusion, our data suggest that CD9 facilitates SARS-CoV-2 infection and that CD9 brings together different host proteins involved in SARS-CoV-2 attachment and entry into host cells, such as ACE2, NRP1, furin, and TMPRSS2. Importantly, the fact that a blocking antibody targeting CD9 can effectively reduce SARS-CoV-2 titers highlights not only the mechanistic role of CD9 in viral entry but also offers translational potential, suggesting that tetraspanin-targeting antibodies could be developed as therapeutic agents against SARS-CoV-2 and possibly other coronaviruses, with meaningful implications for clinical intervention. Full article

Background and Objectives: The cytokine IL-6, methyltransferase NSD2, pro-protein convertase Furin, and growth factor receptor IGF-1R are essential factors in the proliferation of cancer cells. These proteins are involved in the tumor process by generating several cell-signaling pathways. However, the interactions of these oncogenic biomarkers, Furin, IL-6, and NSD2, and their links with the inhibitor SERPINA-1 remain largely unknown. Materials and Methods: Cell proliferation is measured by colorimetric and enzymatic methods. The genetic expressions of SERPINA-1, Furin, IL-6, and NSD2 are measured by qRT-PCR, while the expression of IGF-1R on the cell surface is measured by flow cytometry. Results: The proliferation of cells overexpressing SERPINA-1 (JP7pSer+) is decreased by more than 90% compared to control cells (JP7pSer-). The kinetics of the gene expression ratios of Furin, IL-6, and NSD2 show an increase for 48 h, followed by a decrease after 72 h for the three biomarkers in JP7pSer+ cells compared to JP7pSer- cells. The expression of IGF-1R on the cell surface in both cell lines is low, with JP7pSer- cells expressing 1.33 times more IGF-1R than JP7pSer+ cells. Conclusions: These results suggest gene correlations of SERPINA-1 overexpression with decreased cell proliferation and modulation of gene expression of Furin, IL-6, and NSD2. This study should be complemented by molecular transcriptomic and proteomic experiments to better understand the interaction of SERPINA-1 with IL-6, Furin, and NSD2, and their effect on tumor progression. Full article