Search Results (196)

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

Background/Objectives: Maternal exposures are known to influence the risk of isolated cleft lip with or without cleft palate (CL/P)—a common and highly heritable birth defect with a multifactorial etiology. Methods: To identify new risk loci, we conducted a genome-wide gene–environment interaction (GEI) analysis of CL/P with maternal smoking and vitamin use in Filipinos (N_cases = 540, N_controls = 260). Since GEI analyses are typically low in power and the results can be difficult to interpret, we applied multiple testing frameworks to evaluate potential GEI effects: a one degree-of-freedom (1df) GxE test, the 3df joint test, and the two-step EDGE approach. Results: While no genome-wide significant interactions were detected, we identified 11 suggestive GEIs with smoking and 24 with vitamin use. Several implicated loci contain biologically plausible genes. Notable interactions with smoking include loci near FEZF1, TWIST2, and NET1. While FEZF1 is involved in early neuronal development, TWIST2 and NET1 regulate epithelial–mesenchymal transition, which is required for proper lip and palate fusion. Interactions with vitamins encompass CECR2—a chromatin remodeling protein required for neural tube closure—and FURIN, a critical protease during early embryogenesis that activates various growth factors and extracellular matrix proteins. The activity of both proteins is influenced by folic acid. Conclusions: Our findings highlight the critical role of maternal exposures in identifying genes associated with structural birth defects such as CL/P and provide new paths to explore for CL/P genetics. Full article

Background/Objectives: Neuropilin-1 (NRP1) is a key co-receptor for SARS-CoV-2, complementing the ACE2 receptor. Several investigations have documented highly conserved sequences in this receptor, supporting the implication of NRP1 as a key mediator in SARS-CoV-2 cellular entry mechanisms. Methods: To investigate this hypothesis, we examined 104,737 SARS-CoV-2 genome fastas from GISAID genomic data, corresponding to isolates collected between 2020 and 2025 in Mexico. Specifically, we focused on the RRAR motif, a known furin-binding site for NRP-1 and the binding site for ACE2 with the spike protein. Our analysis revealed high conservation (>98%) of the RRAR domain compared to a rapidly diminishing ACE2-binding domain. A complementary analysis, using Data from Gene Expression Omnibus (GEO, GSE150316), showed that NRP1 expression in lung tissue remains relatively stable, whereas ACE2 displayed high inter-individual variability and lower abundance compared to NRP1. Based on this evidence, we designed two humans–rats NRP1 siRNAs that were tested in vivo using a melittin-induced lung injury model. Results: The RT-PCR assays confirmed an effective NRP1 knockdown, and the siRNA-treated group showed a significant reduction in the lesions severity. These findings highlight NRP1 as a stable and relevant therapeutic target and suggest the protective potential of siRNA-mediated gene silencing. Conclusions: The evidence presented here supports the rational design of NRP1-directed therapies for multiple circulating SARS-CoV-2 variants in Mexico. Full article

Respiratory syncytial virus (RSV) is a major etiological agent of lower respiratory tract infections, particularly among infants and the elderly. Activation of B cells in the mucosa and the production of specific neutralizing antibodies are essential for protective immunity against pulmonary infection. B-cell activating factor (BAFF) is a critical survival factor for B cells and has been associated with antiviral responses; however, its regulation during RSV infection remains poorly understood. This study examined BAFF regulation in BEAS-2B cells exposed to RSV or IFN-β. The treatments resulted in a progressive increase in gene expression over time, accompanied by higher protein levels. BAFF mRNA peaked at 12 h post-infection and declined by 48 h, coinciding with the release of soluble BAFF protein into the culture supernatant. Pre-treatment with anti-IFN-β antibodies prior to RSV infection reduced both BAFF mRNA and protein levels, indicating that IFN-β plays a regulatory role in BAFF production by airway epithelial cells. Western blot analysis revealed membrane-bound BAFF (~31 kDa) in non-infected cells, with elevated expression at 24 h post-infection. By 48 h, this form was cleaved into a soluble ~17 kDa form, which was detected in the supernatant. Immunostaining further demonstrated reduced surface expression of membrane-bound BAFF in RSV-infected cells compared to uninfected controls, suggesting that RSV infection promotes the cleavage and release of BAFF into the extracellular environment. Additionally, the release of BAFF was not affected by furin convertase inhibition or ER–Golgi transport blockade, indicating a potentially novel cleavage mechanism. Co-culturing BAFF produced by BEAS-2B cells with isolated B cells enhanced B cell viability. Overall, these results indicate that RSV infection stimulates BAFF production in airway epithelial cells through a pathway involving IFN-β, potentially contributing to B cell activation and promoting local antibody-mediated immunity. Understanding this mechanism may offer valuable insights for improving mucosal vaccine strategies and enhancing immunity against respiratory pathogens. Full article

From a previously performed proteomics screen, GPP130, or Golgi phosphoprotein of 130 kDa, was identified as a potential substrate of the proprotein convertase 7 (PC7; PCSK7). GPP130 is a type-II transmembrane protein with a luminal domain containing endosomal and Golgi-retrieval determinants, enabling a unique trafficking route. Most of the previous work on GPP130 relates to its binding and retrograde trafficking of the Shiga toxin. However, its cellular biology and its biochemical characterization remain understudied. Recently, GPP130 was reported to be implicated in cell cycle progression and cell proliferation in head and neck cancer cells. This led us to analyze the cBioPortal for Cancer Genomics, revealing that the GPP130/GOLIM4 gene is amplified in many cancers, including lung, ovarian, and cervical. This observation led us to use the A549 lung cancer cell line to investigate the growth-regulating roles of endogenous and overexpressed GPP130 and to analyze the impact of its cleavage/shedding by PC7 and/or Furin on cellular growth. Our cell-based assays suggest that GPP130 is a novel pro-protein convertase substrate that increases cell proliferation in A549, SKOV3, and HeLa cells, and that the latter activity is enhanced following its cleavage by PC7 and/or Furin into a membrane-bound N-terminal product and secreted C-terminal fragments. This novel work sheds light on the cell biology of the poorly characterized GPP130, its proliferative activity, and modulation upon its shedding by PC7 and Furin in lung cancer progression. Full article

The amyloidogenic processing of amyloid precursor protein (APP) plays a pivotal role in the pathogenesis of Alzheimer’s disease (AD), primarily through the generation of amyloid-beta (Aβ) peptides, which aggregate to form toxic plaques in the brain. The regulation of amyloidogenic APP processing is a complex interplay of enzymes, proteins, and signaling pathways, all of which contribute to the development and progression of Alzheimer’s disease. Understanding the intricate mechanisms and molecular players involved in APP processing substantially enhances our knowledge of Alzheimer’s disease pathology and holds promise for the development of biomarkers of ongoing pathology at the earliest stages of Alzheimer’s disease. In this review, we aimed to investigate selected factors that regulate the amyloidogenic pathway of APP processing. Full article

Monomer-to-excimer transition has become a valuable technique in fluorescence imaging because of its ability to enhance imaging contrast. However, from a practical perspective, the accuracy of excimer formation at target sites warrants further exploration. Enzyme-triggered peptide self-assembly provides a promising solution to this limitation. As a proof-of-concept, in this study, we developed a furin-triggered peptide self-assembling fluorescent probe RF-Cou by coupling a coumarin dye 7-(diethylamino)-2-oxo-2H-chromene-3-carboxylic acid (Cou) with a furin-responsive peptide scaffold for precision live-cell imaging. Upon entering furin-overexpressing 4T1 tumor cells, RF-Cou underwent enzymatic cleavage, releasing an amphiphilic peptide motif and self-assembling into nanoparticles largely concentrated in the Golgi apparatus to confine the diffusion of Cou. During this process, the Cou excimers were formed and induced a red shift in the fluorescence emission, validating the feasibility of RF-Cou in efficient excimer imaging of furin-overexpressing tumor cells. We expect that our findings will highlight the potential of stimuli-responsive small molecular peptide probes to advance excimer-based imaging platforms, particularly for enzyme-specific cell imaging and therapeutic monitoring. Full article

The proteolytic processing of the SARS-CoV-2 spike glycoprotein by host cell membrane-associated proteases is a key step in both the entry of the invading virus into the cell and the release of the newly generated viral particles from the infected cell. Because of the critical importance of this step for the viral infectivity cycle, it has been a target of extensive efforts aimed at identifying highly specific protease inhibitors as potential antiviral agents. An alternative strategy to disrupt the pre-fusioviden processing of the SARS-CoV-2 S glycoprotein aims to protect the substrate rather than directly inhibit the proteases. In this work, we focused on furin, a serine protease located primarily in the Golgi apparatus, but also present on the cell membrane. Its cleavage site within the S glycoprotein is located within the stalk region of the latter and comprises an arginine-rich segment (SPRRARS), which fits the definition of the Cardin–Weintraub glycosaminoglycan recognition motif. Native mass spectrometry (MS) measurements confirmed the binding of a hexadecameric peptide representing the loop region at the S1/S2 interface and incorporating the furin cleavage site (FCS) to heparin fragments of various lengths, as well as unfractionated heparin (UFH), although at the physiological ionic strength, only UFH remains tightly bound to the FCS. The direct LC/MS monitoring of FCS digestion with furin revealed a significant impact of both heparin fragments and UFH on the proteolysis kinetics, although only the latter had IC50 values that could be considered physiologically relevant (0.6 ± 0.1 mg/mL). The results of this work highlight the importance of the long-range and relatively non-specific electrostatic interactions in modulating physiological and pathological processes and emphasize the multi-faceted role played by heparin in managing coronavirus infections. Full article

Objective: We developed a targeted integration-based CHO cell platform for simultaneous antibody display and secretion, enabling a streamlined transition from antibody library screening to production without requiring the re-cloning of antibody genes. Methods: The platform consists of a CHO master cell line with a single-copy landing pad, a helper vector expressing FLPe recombinase, and bi-functional targeting vectors. Recombinase-mediated cassette exchange was utilized to integrate targeting vectors into the landing pad. Bi-functional vectors were designed by incorporating a minimal furin cleavage sequence (mFCS), RRKR, and various 2A peptides between the heavy chain (HC) and a membrane anchor. Results: Incomplete cleavage at the mFCS and 2A sites facilitated the expression of both membrane-bound and secreted antibodies, while mutations in the 2A peptide produced a range of display-to-secretion ratios. However, a fraction of secreted antibodies retained 2A residues attached to the HC polypeptides. Further analysis demonstrated that modifying the first five amino acids of the 2A peptide significantly influenced furin cleavage efficiency, resulting in different display-to-secretion ratios for targeting vectors containing mFCS-2A variant combinations. To overcome this, we designed nine-amino-acid FCS variants that, when placed between the HC and membrane anchor, provided a range of display-to-secretion ratios and eliminated the issue of attached 2A residues in the secreted antibodies. Vectors with lower display levels proved more effective at distinguishing cells expressing high-affinity antibodies with closely matched binding affinities. The platform also demonstrated high sensitivity in isolating high-affinity antibody-expressing cells and supported robust antibody production. Conclusion: This targeted integration-based CHO platform enables efficient, in-format screening and production of antibodies with tunable display-to-secretion profiles. It provides a powerful and scalable tool for accelerating the development of functional, manufacturable therapeutic antibodies. Full article

Background/Objectives: Enterobacteriaceae, including pathogenic Shigella (S.) flexneri and Escherichia (E.) coli, cause severe gastrointestinal infections through toxins like Shiga and Shiga-like toxins. Antibiotic use is often discouraged due to its potential to increase toxin effects or contribute to the development of resistance. The host protease furin is capable of activating several viral glycoproteins and bacterial toxins, thus enhancing pathogen infectivity. Methods: To assess the therapeutic potential of furin inhibitors, cultured epithelial cell models (IPEC-J2 and MDCK) were used. The effects of MI-1851 and MI-2415 were evaluated after short-term (2 h) and long-term (6 h) exposure to S. flexneri, enterohemorrhagic E. coli (EHEC), and enteropathogenic E. coli (EPEC). Cytotoxicity was determined using the CCK-8 assay, and the inflammatory response was assessed by measuring interleukin (IL)-6 and IL-8 levels. Additionally, extracellular hydrogen peroxide production was monitored in IPEC-J2 cells to evaluate the potential alterations in redox status. Results: Infections with EHEC, EPEC, and S. flexneri significantly reduced the viability of epithelial cells after 6 h of incubation. Furin inhibitors MI-1851 and MI-2415 decreased cytotoxicity and compensated for IL-6 and IL-8 overproduction in cells during infection with EHEC and S. flexneri, but not in cells exposed to EPEC. In addition, they alleviated oxidative stress, particularly during S. flexneri addition. Conclusions: The development of new antimicrobial drugs that act via alternative mechanisms and effectively manage life-threatening enterobacterial infections is of key importance. Targeting furin with inhibitors MI-1851 and MI-2415, thus blocking toxin activation, could prevent the development of antimicrobial resistance, reduce the need for antibiotics and enhance overall treatment outcomes. Full article

Background: Metabolic effects of oleoylethanolamide-based dietary supplement (OEA-DS) were studied in a model of dietary-induced obesity in mice. Obesity was induced by a 2-month high-fat, high-cholesterol diet, resulting in significant morphological changes in liver tissues and elevated cholesterol levels in the animals’ blood serum. Elevated levels of proinflammatory cytokines, oxidative stress, and hepatocyte apoptosis were also observed in the liver tissue. The aim of this study was to examine the mechanisms through which an OEA-based dietary supplement (OEA-DS) exerts a comprehensive influence on multiple aspects of the pathogenesis of MASLD, thereby demonstrating a robust hepatoprotective effect. Methods: mice were fed a high-fat, high-cholesterol diet with or without OEA-DS supplementation. Liver tissues and blood serum were analyzed for cholesterol levels, inflammatory markers (CD68, Iba-1, CD163, IL-1β, IL-6, TNFα), apoptotic markers (Bad, Bax, Bcl-2), nuclear receptors (PPAR-α, PPAR-γ, AdipoR1), and enzymes involved in lipolysis (Acox1, Cpt1a) and cholesterol metabolism (Ldlr, Furin, Pcsk9). Immunohistochemistry, Western blotting, and RT-PCR were used to assess protein expression and gene transcription. Results: administration of OEA-DS normalized cholesterol levels, decreased expression of inflammatory markers (CD68 and Iba-1), pro-apoptotic markers (Bad, Bax) and levels of pro-inflammatory cytokines (IL-1β, IL-6, TNFα). In parallel, the expression of nuclear receptors PPAR-α and PPAR-γ, adiponectin receptor 1 (AdipoR1), and anti-inflammatory (CD163) and anti-apoptotic (Bcl-2) markers have risen. OEA-DS administration induced the expression of liver lipolysis enzymes (Acox1, Cpt1a) and cholesterol metabolism factors (Ldlr, Furin), while simultaneously reducing the transcription of the proatherogenic factor Pcsk9. Conclusions: The results of this study suggest a complex action of OEA-DS in obesity-associated liver damage, which includes reduction of systemic inflammation. Full article

This retrospective study analyzed SARS-CoV-2 Omicron variability since its emergence, focusing on immunocompromised (IPs) and non-immunocompromised adult people (NIPs). Phylogenetic analysis identified at least five major Omicron lineage groups circulating in Central Italy, from December 2021 to December 2023: (a) BA.1 (34.0%), (b) BA.2 + BA.4 (25.8%), (c) BA.5 + BF (10.8%), (d) BQ + BE + EF (9.2%), and (e) Recombinants (20.2%). The BA.2 + BA.4 lineages were more common in IPs compared to NIPs (30.9% vs. 17.8%, respectively; p = 0.011); conversely, Recombinants were less prevalent in IPs than in NIPs (16.0% vs. 27.1%, respectively; p = 0.018). High-abundant single nucleotide polymorphisms (SNPs; prevalence ≥ 40%) and non-synonymous SNPs (prevalence ≥ 20%) increased during the emergence of new variants, rising from BA.1 to Recombinants (54 to 92, and 43 to 70, respectively, both p < 0.001). Evaluating the genetic variability, 109 SNPs were identified as being involved in significant positive or negative associations in pairs (phi > 0.70, p < 0.001), with 19 SNPs associated in 3 distinct clusters (bootstrap > 0.96). Multivariate regression analysis showed that hospitalization was positively associated with one specific cluster, including S686R and A694S in Spike and L221F in Nucleocapsid (AOR: 2.74 [95% CI: 1.13–6.64, p = 0.025]), and with increased age (AOR:1.03 [95% CI: 1.00–1.06], p = 0.028). Conversely, negative associations with hospitalization were observed for female gender and previous vaccination status (AORs: 0.34 [95% CI: 0.14–0.83], p = 0.017 and 0.19 (95% CI: 0.06–0.63, p = 0.006, respectively). Interestingly, the S686R SNP located in a furin cleavage site suggests its potential pathogenetic role. The results show how Omicron genetic diversification significantly influences disease severity and hospitalization, together with age, sex, and vaccination status as key factors. Full article

Background: Breast milk is a rich source of antimicrobial and anti-inflammatory compounds, owing to its diverse array of bioactive molecules. This study explores the presence and activity of natural antimicrobial agents in breast milk, particularly in the context of the SARS-CoV-2 pandemic. Materials and Methods: Breast milk samples were collected from 50 breastfeeding mothers, including those who had either been vaccinated against SARS-CoV-2 or had recovered from the infection. These samples were compared with a control group consisting of 10 unvaccinated mothers with no history of COVID-19. Key antimicrobial and immune-regulatory proteins—lactoferrin, lactadherin, furin, tenascin C, granzyme B, and chitinase 3-like 1—were quantified using the Luminex multiplex analyzer. Results and Discussion: All targeted biomarkers were detected in breast milk, providing insights into the immune profile transferred to infants following COVID-19 infection or vaccination. These bioactive molecules highlight breastfeeding’s role in providing passive immunity and antimicrobial protection. The protein levels were found to be influenced by factors such as maternal inflammation, infant age, delivery mode, and parity, emphasizing the dynamic interaction between maternal immunity, lactation biology, and infant development. Conclusion: Breastfeeding serves as a powerful anti-SARS-CoV-2 defense mechanism, supported by the activity of lactoferrin, lactadherin, and furin, reinforcing its critical role in child health. Full article

Background: Proteolytic cleavage of inactive pathogen proteins by furin is critical for their entry into human cells, and thus furin cleavage of the SARS-CoV-2 spike protein was identified as a prerequisite for virus binding and the subsequent infection of human cells in the recent COVID-19 pandemic. We report a water-aware structure-based protease inhibitor design study. Methods: Our efforts focused on the biological evaluation of small molecule inhibitors that emerged from a conserved water-aware virtual screening campaign of a library of compounds that shared structural or physicochemical properties with known furin inhibitors exhibiting newly recognized binding modes. Results: We identified a novel small-molecule furin protease inhibitor with a 1,3-thiazol-2-ylaminosulfonyl scaffold. Namely, the compound N-[4-(1,3-thiazol-2-ylaminosulfonyl)phenyl]-3-{(E)-5-[(2-methoxyphenyl)methylene]-4-oxo-2-thioxo-1,3-thiazolidin-3-yl}propionamide showed an IC₅₀ value of 17.58 μM, comparable to other published inhibitors. Conclusions: This compound could represent a starting point for the further design and development of non-peptidic, small-molecule furin inhibitors that could assist in furin cleavage studies and coronaviral pathogenesis. Full article

Bovine coronavirus (BCoV) exhibits dual tissue tropism, infecting both the respiratory and enteric tracts of cattle. Viral entry into host cells requires a coordinated interaction between viral and host proteins. However, the specific cellular receptors and co-receptors facilitating BCoV entry remain poorly understood. Similarly, the roles of host proteases such as Furin, TMPRSS2, and Cathepsin-L (CTS-L), known to assist in the replication of other coronaviruses, have not been extensively explored for BCoV. This study aims to identify novel BCoV receptors and host proteases that modulate viral replication and tissue tropism. Bovine cell lines were infected with BCoV isolates from enteric and respiratory origins, and the host cell gene expression profiles post-infection were analyzed using next-generation sequencing (NGS). Differentially expressed genes encoding potential receptors and proteases were further assessed using in-silico prediction and molecular docking analysis. These analyses focused on known coronavirus receptors, including ACE2, NRP1, DPP4, APN, AXL, and CEACAM1, to identify their potential roles in BCoV infection. Validation of these findings was performed using the qRT-PCR assays targeting individual genes. We confirmed the gene expression profiles of these receptors and enzymes in some BCoV (+/−) lung tissues. Results revealed high binding affinities of 9-O-acetylated sialic acid and NRP1 to BCoV spike (S) and hemagglutinin-esterase (HE) proteins compared to ACE2, DPP4, and CEACAM1. Additionally, Furin and TMPRSS2 were predicted to interact with the BCoV-S polybasic cleavage site (RRSRR|A), suggesting their roles in S glycoprotein activation. This is the first study to explore the interactions of BCoV with multiple host receptors and proteases. Functional studies are recommended to confirm their roles in BCoV infection and replication. Full article