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Objective: Although the neurological and olfactory symptoms of coronavirus disease 2019 have been identified, the neurotropic properties of the causative virus, severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2), remain unknown. We sought to identify the susceptible cell types and potential routes of SARS-CoV-2 entry into the central nervous system, olfactory system, and respiratory system. Method(s): We collected single-cell RNA data from normal brain and nasal epithelium specimens, along with bronchial, tracheal, and lung specimens in public datasets. The susceptible cell types that express SARS-CoV-2 entry genes were identified using single-cell RNA sequencing and the expression of the key genes at protein levels was verified by immunohistochemistry. We compared the coexpression patterns of the entry receptor angiotensin-converting enzyme 2 (ACE2) and the spike protein priming enzyme transmembrane serine protease (TMPRSS)/cathepsin L among the specimens. Result(s): The SARS-CoV-2 entry receptor ACE2 and the spike protein priming enzyme TMPRSS/cathepsin L were coexpressed by pericytes in brain tissue;this coexpression was confirmed by immunohistochemistry. In the nasal epithelium, ciliated cells and sustentacular cells exhibited strong coexpression of ACE2 and TMPRSS. Neurons and glia in the brain and nasal epithelium did not exhibit coexpression of ACE2 and TMPRSS. However, coexpression was present in ciliated cells, vascular smooth muscle cells, and fibroblasts in tracheal tissue;ciliated cells and goblet cells in bronchial tissue;and alveolar epithelium type 1 cells, AT2 cells, and ciliated cells in lung tissue. Conclusion(s): Neurological symptoms in patients with coronavirus disease 2019 could be associated with SARS-CoV-2 invasion across the blood-brain barrier via pericytes. Additionally, SARS-CoV-2-induced olfactory disorders could be the result of localized cell damage in the nasal epithelium.Copyright © Wolters Kluwer Health, Inc. All rights reserved.
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Background/Objectives: Emerging evidence suggests that complement system infection-dependent hyperactivation may worsen COVID-19 outcome. We investigated the role of predicted high impact variants -referred as Qualifying Variants (QVs) -of complement system genes in predisposing asymptomatic COVID-19 in elderly individuals, known to be more susceptible to severe disease. Method(s): Exploiting Whole-Exome Sequencing (WES) data and 56 complement system genes, we performed a gene-based collapsing test between 164 asymptomatic subjects (age >= 60 y.o.) and 56,885 European individuals from the gnomAD database. We replicated this test comparing the same asymptomatic individuals with 147 hospitalized COVID-19 patients. Result(s): We found an enrichment of QVs in three genes (MASP1, COLEC10 and COLEC11), which belong to the lectin pathway, in the asymptomatic cohort. Moreover, individuals with QVs showed lower serum levels of Masp1 and of prothrombin activity compared to controls while no differences were observed for CH50 and AH50 levels that measure the activity of classical and alternative complement pathways, respectively. Finally, integrative analyses of genome-wide association study and expression quantitative loci traits data showed a correlation between polymorphisms associated with asymptomatic COVID-19 and decreased expression of MASP1, COLEC11 and COLEC10 genes in lung tissue. Conclusion(s): This study suggests that rare genetic variants can protect from severe COVID-19 by mitigating the activation of lectin pathway and prothrombin activity.
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Introduction: Multiple meta-analyses have shown that over 15% patients with COVID-19 have at least one gastrointestinal complaint, most commonly diarrhea. The effects on the gastrointestinal system are thought to be mediated by the high expression of angiotensin-converting enzyme 2 (ACE2) and cellular serine proteases (TMPRSS2) in enterocytes, which cause altered intestinal permeability. The purpose of this study was to determine the incidence of diarrhea as it relates to COVID-19 infection and to determine if having concomitant diarrhea had a significant impact on disease course. Method(s): A retrospective chart review of 164,730 patients in a hospital system who were older than 18 years of age and had a positive SARS-CoV-2 test from March 2020 to February 2022 was completed. Diarrhea was determined using ICD code or patient's symptoms. Patients with confounding variables such as IBD, IBS, Celiac, Clostridium difficile, and pancreatic insufficiency were excluded. Demographic clinical characteristics and outcomes, including inpatient admission and mortality, were compared in patients with and without diarrhea. The Mann-Whitney test and Fisher's exact or Chi-square test was used for continuous and categorical variables respectively and multivariate logistic regression was used to evaluate for significant differences in disease outcome between the two groups. (Table) Results: Of the 164,730 patients included, 14,648 (8.89%) had diarrhea at the time of SARS-CoV-2. 6,748/33,464 (20.16%) of inpatient admissions were associated with diarrhea. On multivariate analysis, diarrhea was an independent risk factor for inpatient hospitalization (OR 2.39, CI 95% 2.28-2.51, P, 0.001) and inpatient mortality (OR 1.15, CI 96% 1.06-1.26, P= 0.001) after controlling for age, gender, race, comorbidities that could impact patient outcome, use of immunomodulators and outpatient antibiotics. Conclusion(s): These findings show that, even with controlling for comorbidities with COVID-19, diarrhea was an independent factor for predicting inpatient mortality and inpatient admission in general. Patients who had diarrhea and COVID-19 were sicker, having more comorbid conditions than those without diarrhea in our cohort. Attention should be given to not only respiratory complaints of COVID-19, but also gastrointestinal complaints, as they are an indicator of poor prognosis and mortality.
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Background: COVID-19 may be more severe in persons with HIV (PWH). However, underlying biological mechanisms associated with the development of COVID-19 and its clinical severity among antiretroviral therapy (ART) treated PWH are largely unknown. Therefore, we wished to evaluate temporal changes in plasma proteins following SARS-CoV-2 infection and identify pre-infection proteomic markers associated with future COVID-19. Method(s): We analyzed the data of clinical, antibody-confirmed COVID-19 ARTtreated PWH from the global Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE). Individuals were matched on geographic region, age, and sample timing to antibody-negative controls. For cases and controls, pre-COVID-19 pandemic specimens were obtained prior to January 2020 to assess temporal changes and baseline differences in protein expression in relationship to COVID-19 severity, using mixed effects models adjusted for false-discovery rate. Result(s): We compared 257 unique plasma proteins (Olink Proteomics) in 94 COVID-19 antibody-confirmed clinical cases and 113 matched antibody-negative controls, excluding COVID-19 vaccinated participants (median age 50 years, 73% male). 40% of cases were characterized as mild;60% moderate to severe. Median time from COVID-19 infection to follow-up sampling was 4 months. Temporal changes in protein expression differed based on COVID-19 disease severity. Among moderate to severe cases vs. controls, NOS3 increased, whereas ANG, CASP-8, CD5, GZMH, GZMB, ITGB2, and KLRD1 decreased. Higher baseline circulating concentrations of granzymes A, B and H (GZMA, GZMB and GZMH) were associated with the future development of moderate-severe COVID-19 in PWH and were related to immune function, including CD4, CD8 and the CD4/ CD8 ratio. Conclusion(s): We identified temporal changes in novel proteins in closely linked inflammatory, immune, and fibrotic pathways which may relate to COVID-19-related morbidity among ART-treated PWH. Further, we identified key granzyme proteins, serine proteases expressed by cytotoxic T lymphocytes and NK cells in response to foreign antigens, associated with future COVID-19 in PWH. Our results provide unique insights into the biological susceptibility and responses to COVID-19 infection in PWH. (Figure Presented).
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The strategy of drug repurposing has been proved successful in response to the current corona-virus pandemic, with remdesivir becoming the first drug of choice, an antiviral drug approved for the treatment of COVID-19. In parallel to this, several drugs, such as antimalarial, corticosteroids, and antibi-otics, like azithromycin, are used to treat the severe condition of hospitalized COVID-19 patients, while clinical testing of additional therapeutic drugs, including vaccines, is going on. It is reasonably expected that this review article will deliver optimized and specific curative tools that will increase the attentive-ness of health systems to the probable outlook of epidemics in the future. This review focuses on the ap-plication of repurposed drugs by studying their structure, pharmacokinetic study, different mechanisms of action, and Covid-19 guidelines, which can potentially influence SARS-CoV-2. For most of the drugs, direct clinical evidence regarding their effectiveness in the treatment of COVID-19 is missing. Future clinical trial studies may conclude that one of these can be more potential to inhibit the progression of COVID-19.Copyright © 2022 Bentham Science Publishers.
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Background: To search for molecular biomarkers of pulmonary pathologies using non-invasive samples, such as urine, is of high clinical relevance. However, there are almost no proteomic studies using urine applied to respiratory diseases. Aim(s): To develop a biomarker discovery strategy using non-targeted proteomics in urine with applicability to different pulmonary diseases. Method(s): Urine samples were centrifuged and DTT treated to decrease uromodulin (THP). Low-THP samples were concentrated (ultrafiltration), ultracentrifugated, and exosome free urine was analysed using LC-MS/MS. GO terms/Pathway analyses were performed using STRING database. Result(s): Urine proteome (765 proteins) was enriched (FDR < 0.05) in proteins from different tissues, including respiratory system (N = 124), lung (N = 107), and immune system (N = 88). We detected an enrichment of relevant pathways for respiratory diseases, including several innate (e.g., TLR and NFkB pathways, complement system), and adaptive (e.g., interleukin signalling) immune system pathways. Some of these proteins have been previously studied in respiratory system disease (e.g., MPO, NAPSA, CHL1, FREM2, PLG), lower respiratory tract disease (e.g., NCAM1, MTOR, SERPINA1), viral infectious disease (e.g., ITIH4, CD209, CLEC4M, CD55), or specific pathologies such as coronavirus infection (e.g., ACE2, TMPRSS2), bronchiectasis (e.g., SAA1, SAA2, ELANE) or asthma (e.g., IGFALS, IGFBP7, HSPG2, DPP4, CD44, IL6R, MASP1). Conclusion(s): We have developed a protocol for the detection of proteomic biomarkers in urine. This proteome is enriched in proteins from the immune and respiratory systems, with a potential clinical and translational relevance.
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Background: Neutrophil serine proteases (NSPs) are involved in the pathogenesis of COVID19 and are increased in severe and fatal infection. We investigated whether treatment with Brensocatib, an inhibitor of dipeptidyl peptidase-1, an enzyme responsible for the activation of NSPs, would improve outcomes in hospitalized patients with COVID19. Method(s): In a randomized, double-blind, placebo-controlled trial, 406 hospitalized patients with COVID19 with at least one risk factor for severe disease were randomized 1:1 to once-daily Brensocatib 25mg (n=192) or placebo (n=214) for 28 days. Primary outcome was the 7-point World Health Organisation Clinical Status scale at day 29. Secondary outcomes included time to clinical improvement, national early warning score, new oxygen and ventilation use, neutrophil elastase activity in blood and mortality. Finding(s): Brensocatib treatment was associated with worse clinical status at day 29 (adjusted odds ratio 0 72, 95%CI 0 57-0 92) compared to placebo. The adjusted hazard ratio (aHR) for time to clinical improvement was 0 87 (95%CI 0 76-1 00) and time to hospital discharge was 0 98 (95%CI 0 84-1 13). During the 28-day follow-up period, 23 (11%) and 29 (15%) patients died in the placebo and Brensocatib treated groups respectively). Oxygen and new ventilation use were greater in the Brensocatib treated patients. Neutrophil elastase activity in blood was significantly reduced in the Brensocatib group from baseline to day 29. Prespecified subgroup analyses of the primary outcome supported the primary results.
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Background: The deadly outbreak of COVID-19 disease caused by novel SARS CoV2 has created an unprecedented global health crisis affecting every sectors of human life and enor-mous damage to world's economy. With >16.1 million infections and >650,000 deaths worldwide as of July 27, 2020, there is no treatment for this disease neither is there any available vaccine. Seri-ous research efforts are ongoing on all fronts including treatment, prevention and diagnosis to combat the spread of this infection. A number of targets that include both viral and host proteins have been identified and became part of intense investigation. In this respect the viral surface spike (S) glycoprotein caught the attention most. It is cleaved by multiple host proteases to allow recognition by host receptor human Angiotensin Converting Enzyme2 (hACE2) leading to fusion and viral re-plication. Natural products, small compounds, antioxidants, peptides, proteins, oligonucleotides, antibodies and other compounds are under investigation for development of antiviral agents against COVID-19. Objective(s): Recently cholesterol lowering phytocompounds Quercetin, Swertiamarin and Berberine which promote human Low Density Lipoprotein Receptor (hLDLR) via inhibition of human Pro-protein Convertase Subtilisin Kexin9 (hPCSK9) have been shown to block viral infections caused by ebola, influenza, Respiratory Syncytial Virus (RSV), Hepatitis C virus (HCV) and other RNA type viruses. Since SARS CoV2 is a RNA virus with similar genetic structure and infection machin-ery, it is hypothesised that these phytocompounds may also exhibit antiviral property against COVID-19. Method(s): Our above concept is based on recently published studies as well as our herein presented in silico modeling and computational data which suggested strong interactions of hPCSK9 with above phytocompounds and most importantly with hACE2 following its complexation with receptor binding domain (RBD) of SARS CoV2 S protein. Result(s): These results and a proposed schematic model showing association of hPCSK9 with SARS CoV2 infection are presented in this manuscript. It is proposed that hPCSK9 plays the role of a co-receptor in binding with hACE2:RBD complex and thereby facilitates viral fusion. Conclusion(s): Our studies suggest that PCSK9 inhibitors may provide beneficial effect against COVID-19 infection by retarding viral fusion through displacement of bound hPCSK9 from its complex with ACE2:RBD of SARS CoV2 S protein.Copyright © 2021 Bentham Science Publishers.
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Purpose : Bacterial keratitis is a prevalent eye infection that causes corneal opacification and purulent discharge, especially among contact lens wearers. Such infections recruit innate immune cells into the cornea, predominately neutrophils (PMN). CD177 is a GPIanchored protein expressed on ∼50% of circulating PMN. Proteinase-3 (PR3) is a serine protease that binds CD177 and is shown to be released from PMN granules upon activation or expressed on the plasma membrane (mPR3). CD177 PMN can be protective or pathogenic in various diseases ranging from IBD to COVID-19. On the other hand, elevated PR3 is found in patients with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated systemic vasculitis. With little known regarding the eye, this study investigates the expression and role(s) of CD177 and PR3 in the cornea following bacterial keratitis. Methods : This work uses an experimental model of bacterial keratitis carried out in 8-week-old, female susceptible C57BL/6 (B6) and resistant BALB/c mice. The left eye of each mouse was scarified then infected with P. aeruginosa ATCC strain 19660 (5 μL of 1 x 106 CFU). Corneas from naïve, uninfected mice from both strains served as controls. Corneas were harvested at 1, 3, and 5 days post-infection (p.i.). Levels of CD177 and PR3 were determined at the protein level by Western blot and by phenotypic profiling using flow cytometry. In vitro assessment was carried out using HL-60, a human promyelocytic cell line, and siCD177 knockdown. Results : Results from the in vivo model showed no differences in protein levels at 1 day p.i., but significantly higher levels of both CD177 and PR3 in B6 vs. BALB/c at 3 and 5 days p.i. Flow cytometry data revealed CD177+ and PR3+ expression on both PMN and macrophages from B6 and BALB/c infected corneas with differential mean fluorescence intensities detected between the strains under normal conditions and following infection. In vitro results indicated that cell activation was altered following CD177 knockdown with differences in downstream signaling. Conclusions : As one of the first studies to explore the role of CD177 and PR3 in the pathogenesis of bacterial keratitis, our findings reveal strain-specific expression profiles for PMN that may contribute to resistance vs. susceptibility. In addition, we show the presence of CD177 PR3 macrophages. Overall, these findings may uncover novel therapeutic targets to treat bacterial keratitis.
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Introduction SARS-CoV-2 variants of concern (VOCs) represent an alarming threat as they may escape vaccination effectiveness. Broad-spectrum antivirals could complement and further enhance preventive benefits achieved through SARS-CoV-2 vaccination campaigns. Aim Testing the antiviral activity of Echinacea purpurea against VOCs and exploring underlying modes-of-action. Method A hydroethanolic extract of freshly harvested E. purpurea herb and roots (Echinaforce®, EF extract) was tested to inhibit infection of VOCs B1.1.7 (alpha), B.1.351.1 (beta), P.1 (gamma), B1.617.2 (delta), AV.1 (Scottish) and B1.525 (eta). Molecular dynamics (MD) were used to study interaction of EF phytochemical markers with known pharmacological viral and host cell targets. Results EF broadly inhibited propagation of all tested SARS-CoV-2 VOCs at EC50 < 12.0 ;jg/ml. Treatment of epithelial cells with 20 jg/ml EF prevented sequential infection with SARS-CoV-2 (Hu-1). MD analyses showed for alkylamides, caftaric acid and feruoyl-tartaric constant binding affinity to spike proteins of all VOCs and to TMPRSS-2, a serine protease required for virus endocytosis. Conclusion EF extract exhibits virucidal activity against all tested SARS-CoV-2 VOCs and protects epithelial cells from infection.
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Background: Autoimmune diagnosis plays an important role in the diagnosis, classification and prognosis of systemic autoimmune rheumatic diseases (SARD). The coronavirus disease 2019 (COVID-19) pandemic has a profound impact on clinical and diagnostic practices on a global scale. In the current study we aimed to provide reliable data on the effects of COVID-19 pandemic on autoimmunity testing requests, rate of positivity and rheumatological clinical practices. Methods: Data on autoimmunity test numbers, positive results, first rheumatological visits and new diagnosis have been collected from medical records and laboratory information system for the COVID-19 pandemic phase (January-December 2020) and compared with those obtained during the corresponding period in 2019. The list of autoantibodies included: anti-nuclear antibody, anti-extractable nuclear antigens, anti-dsDNA, rheumatoid factor, anti-citrullinated protein-peptide antibodies and antineutrophil cytoplasmic antibodies (anti-myeloperoxidase and anti-serine proteinase 3). Results: A statistically significant reduction of all laboratory parameters investigated were found during the pandemic period (9912 vs. 14,100 for all patients, P<0.05;1547 vs. 2276 for selected outpatients only, P<0.05). A significant reduction in first rheumatological visits and new diagnosis was also observed with an absolute difference between study periods equal to 1064 rheumatological visits (1272 vs. 2336, P<0.05) meaning a total visits decreasing of 48%. The decline was more sustained during the first wave of the pandemic and less pronounced during the second wave. However, an equivalent or higher percentage of positive test results from outpatients were recorded during 2020 when compared to prepandemic state and the decline in new diagnosis mainly affected less severe diseases. In contrast, SARD with systemic involvement were diagnosed without significant differences. Conclusions: Our data showed a greater appropriateness of autoantibodies request and rheumatological visits during the COVID-19 pandemic compared to prepandemic period, as demonstrated by a higher percentage of positive results and new diagnosis of more severe SARD.
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Background: SARS-CoV-2 has caused a global pandemic, yet despite vaccine availability, it continues to inflict morbidity and mortality worldwide. The viral main protease (Mpro) is highly conserved across multiple coronaviruses and has a unique viral substrate specificity. Thus, highly selective Mpro inhibitors are expected to be safe, effective, and elude drug resistance for future coronaviruses. Methods: We used a conformationally restricted peptidomimetic to mimic the bioactive conformation of the Mpro-substrate complex to identify potent, selective Mpro inhibitors. We evaluated protease inhibition in biochemical assays, and cellular efficacy in Vero-E6 cells challenged with live virus representing parental (USA-WA1/2020), beta (B.1.351), and delta (B.1.617.2) variants by monitoring infection at day 2 post-infection measuring nucleocapsid-positive cells by high content imaging, and cytopathic effect (CPE) at day 4 post-infection using resazurin viability dye. Results were compared to reference compounds. Group differences were analyzed by two-sided, paired t-test. Results: AP-8-013 required a 2-hour incubation to achieve maximal dose-dependent Mpro inhibition with an IC50 = 230 ± 18 nM, reflecting its highly constrained conformation, compared to the more flexible Cpd 22 (AP-8-001;IC50 = 11 ± 0.7 nM) or GC-376 (IC50 = 18 ± 1.5 μM). Importantly, AP-8-013 showed exquisite selectivity for Mpro with no inhibition at key mammalian cysteine proteases, cathepsin B and L, or the serine protease thrombin, while Cpd 22 (Cat B IC50 = 24 ± 7.5 nM, Cat L IC50 = 1.8 ± 0.3 nM) or GC-376 (Cat B IC50 = 37 ± 1.5 nM, Cat L IC50 = < 1 nM) showed poor selectivity towards mammalian cysteine proteases. AP-8-013 was active in CPE cell-based assays with comparable potency to reference compounds, with EC50 = 4.7 μM compared to Cmp 22 (EC50 = 1.4 μM) or GC-376 (EC50 = 1.1 μM). Using intact SARS-CoV-2 infection-based assays, AP-8-013 significantly inhibited parental virus as well as beta and delta VOC (EC50s = 2.7, 2.5, and 6.0 μM, respectively). Finally, a 3:1 molar mixture of AP-8-013 and remdesivir significantly enhanced antiviral activity in CPE assays (EC50 = 1.3 μM;p < 0.05) when compared against either compound alone (EC50s = 4.7 and 3.3 μM, respectively). Conclusion: We have identified a novel drug-like Mpro inhibitor lead series which is highly selective over cysteine and serine proteases that can inhibit multiple SARS-CoV-2 VOC and increase the antiviral activity of remdesivir.
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Due to the urgent need of drugs to control the COVID-19 pandemic, repo-sitioning of already marketed drugs could be a fast and convenient option to identify agents to aid in controlling and treating COVID-19. This work presented a computational work regarding homology modeling and molecular docking of repurposing drugs related to the SARS-CoV-2. We have cre-ated a homology model of the cell surface transmembrane protease serine 2 protein (TMPRSS2) in order to investigate and analyze the interac-tions of already known small-molecules. This study indicates the most active inhibitors, poceprevir, simeprevir and neoandrgrapholide, that can be used further to search for better TMPRSS2 inhibitors. Moreover, we analyzed the most important atomistic connections between these compounds and the modeled protein pockets. This study will focus on TMPRSS2-targeted drugs by comparing the binding mode of approved and experimentally used TMRSS2 inhibitors with other agents with TMPRSS2 inhibitory activity and could potentially inhibit SARS-CoV-2 and therefore could lead to the identification of new agents for further clinical evaluation of SARS-CoV-2 and potential treatment of COVID-19.
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Background: Complement dysregulation has been documented in the molecular pathophysiology of COVID-19 and recently implicated in the relevant pediatric patient inflammatory responses. Aims: Based on our previous data in adults, we hypothesized that signatures of complement genetic variants would also be detectable in pediatric patients exhibiting COVID-19 signs and symptoms. Methods: We prospectively studied consecutive pediatric patients from our COVID-19 Units (November 2020-March 2021). COVID-19 was confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR). Patient data were recorded by treating physicians that followed patients up to discharge. DNA was obtained from peripheral blood samples. Probes were designed using the Design studio (Illumina). Amplicons cover exons of complement-associated genes (C3, C5, CFB, CFD, CFH, CFHR1, CFI, CD46, CD55, MBL2, MASP1, MASP2, COLEC11, FCN1, FCN3 as well as ADAMTS13 and ΤHBD) spanning 15 bases into introns. We used 10ng of initial DNA material. Libraries were quantified using Qubit and sequenced on a MiniSeq System in a 2x150 bp run. Analysis was performed using the TruSeq Amplicon application (BaseSpace). Alignment was based on the banded Smith-Waterman algorithm in the targeted regions (specified in a manifest file). We performed variant calling with the Illumina-developed Somatic Variant Caller in germline mode and variant allele frequency higher than 20%. Both Ensembl and Refseq were used for annotation of the output files. A preliminary analysis (A) for the identification of variants of clinical significance was based on annotated ClinVar data, while a further and more selective analysis (B) was performed to identify missense complement coding variants that may biochemically contribute to the deregulation of innate responses during infection. This analysis was mainly based on the dbSNP and UniProt databases and available literature. Results: We studied 80 children and adolescents, 8 of whom developed inflammatory syndromes (MIS-C group). Among them, 41 were hospitalized and eventually all survived. 1. In our preliminary analysis, patients exhibited heterogeneous variant profiles including pathogenic, benign, likely benign, and variants of unknown significance (median number of variants: 97, range: 61-103). We found a variant of ADAMTS13 (rs2301612, missense) in 39 patients. We also detected two missense risk factor variants, previously detected in complement-related diseases: rs2230199 in C3 (33 patients);and rs800292 in CFH (36 patients). Among them, 40 patients had a combination of these characterized variants. This combination was significantly associated with the presence of dyspnea (p=0.031) and cough (p=0.042). Furthermore, 27 patients had a pathogenic variant in MBL2 (rs1800450), and 7 a pathogenic deletion in FCN3 that have been previously associated with inflammatory syndromes. 2. The results of our further analysis are summarized in Figure. We identified common variants, some well represented by relatively high frequencies (>70%) (rs11098044 in CFI, rs1061170 in CFH and rs12711521 in MASP2) and others less abundant, but varying considerably between the hospitalized group, the non-admitted group and the MIS-C individuals (rs2230199 in C3, rs1065489 in CFH, rs12614 and rs641153 in CFB, rs1800450 in MBL2, rs2273346 and rs72550870 in MASP2, rs72549154 in MASP3 and rs7567833 in COLEC11, all highlighted in Figure in red).). Structurally, the majority of these common variants of interest encode charge reversal mutations. These may influence protein-protein interactions in complex formations that are important for complement activation and/or regulation. Conclusion: In pediatric COVID-19 we have detected a novel set of complement missense coding variants some of which have been implicated earlier in inflammatory syndromes and endothelial stress responses. Certain combinations of mutations of alternative and/or lectin pathway components may increase the threshold dynamics of complement consumption and therefore alter COVID-19 phenotypes. [Formula prese ted] Disclosures: Gavriilaki: Alexion, Omeros, Sanofi Corporation: Consultancy;Gilead Corporation: Honoraria;Pfizer Corporation: Research Funding. Anagnostopoulos: Abbvie: Other: clinical trials;Sanofi: Other: clinical trials;Ocopeptides: Other: clinical trials;GSK: Other: clinical trials;Incyte: Other: clinical trials;Takeda: Other: clinical trials;Amgen: Other: clinical trials;Janssen: Other: clinical trials;novartis: Other: clinical trials;Celgene: Other: clinical trials;Roche: Other: clinical trials;Astellas: Other: clinical trials.
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Context: There have been two coronavirus-related pandemics during the past 18 years, including severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV in 2002 and 2012, respectively. In 2019, Seven years after the emergence of MERS, a new coronavirus (i.e., SARS-CoV-2) was detected in several patients. SARS-CoV-2 spread widely, and its high prevalence enabled the virus to start a new pandemic in 2020. It is believed that the higher infectivity of the virus in comparison to that of SARS-CoV is related to its molecular interaction affinity of transmembrane spike glycoprotein and human angiotensin-converting enzyme 2 (ACE-2) cell receptors. Moreover, the primary reason for the high case fatality rate (CFR) is the cytokine storm and acute respiratory distress syndrome (ARDS) because of the immune system response to the invaders. Hence, a solid understanding of the components involved in the mechanism of viral entry and immune system response is crucial for finding approaches to disrupt the virus-cell interplay and neutralizing its impacts on the host immune system. In this review, we investigated the molecular aspect and potential therapeutic targets associated with cell receptors and downstream signaling cascades. Evidence Acquisition: A systematic search was implemented on several online databases, including Google Scholar, PubMed, and Scopus during 2019-2021 using the following keywords: "SARS-CoV-2", "COVID-19", "ACE-2", "Therapeutic Targets", "Acute Respiratory Distress Syndrome", and "Cytokine Storm". Results: Various internal or external agents are responsible for the virus infectivity and stimulating acute immune system response. Since currently there is no cure for the treatment of COVID-19, several repurposed drugs can be employed to disrupt the process of viral entry and mitigate the symptoms raised by the cytokine storm. Inhibition of several agents, including signal transduction mediators and TMPRSS2 may be momentous. Conclusions: Despite the increase in the CFR, no drugs were developed with significant efficacy. Understanding the virus entry mechanism and the immune system’s role could help us surmount the problems in developing a promising drug or employing the repurposed ones. © 2021, Author(s).
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Neutrophils, which are among the first immune cells to respond to both infection and injury, when activated can release pre-stored serine proteases such as neutrophil elastase, cathepsin G and proteinase 3. An abundant release of these proteolytic enzymes in the alveolar compartment as well as the airways can trigger collateral pulmonary tissue damage. Indeed, much of the tissue destruction that characterizes non-cystic fibrosis bronchiectasis appears to be caused by serine proteases. The transitory pharmacological inhibition of bone marrow dipeptidyl peptidase 1 (DPP1), which converts neutrophil proteolytic enzymes into their mature active form, is a therapeutic possibility to decrease the constitutively produced serine protease pool of neutrophils. Brensocatib (also called INS-1007 or AZD-7986) is a potent reversible DPP1 inhibitor that has been successfully evaluated in a phase II trial as a treatment for non-cystic fibrosis bronchiectasis and, consequently, has been granted breakthrough therapy designation by the U.S. Food and Drug Administration and Priority Medicines (PRIME) designation by the European Medicines Agency.
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Background: Mannose-binding lectin (MBL)-associated serine protease-2 (MASP-2) is an indispensable enzyme for the activation of the lectin pathway (LP) of complement-one of the important pathways of the first line non-specific defence against infections. MASP-2 complexed with pattern recognition molecules such as MBL, other collectins, and ficolins and has been implicated in the activation of the LP of complement. Some studies describe the dual behaviour of the MASP: the low genetic expression, as well as nonfunctional MASP-proteins, which lead to a compromised immune response against the pathogen, facilitating infection and disease progression or, conversely, increased levels of MASP-2, which may be harmful due to the possibility of an unbalanced proinflammatory response and an additional host injury in serious diseases conditions, such as COVID-SARS. The role of the MASP-2 according to severity, control and exacerbation of asthma poorly understood and we aimed to evaluate the MASP-2 plasma level according to asthma severity and exacerbation status in children. Method: Total 95 children aged 7-18 referred to a pediatric allergy centre (European population of East Siberia, Russia) were divided into three groups: mild, moderate and severe asthma. The diagnosis, severity of the disease were established according to GINA-2020. Control group was represented by 70 age-and sex-matched noneasthmatics (essentially healthy children without signs of infection or allergies). MASP-2 levels were measured using an ELISA kit (Hycult Biotech, The Netherlands). Quantitative data are shown as median (25-75% quartiles). Results: We have found that in children with virus-induced asthma exacerbation (n = 95) MASP-2 plasma concentration increased in severe asthma (Fig. 1). Additionally, plasma MASP-2 levels were increased in asthma exacerbation groups, regardless of virus-induced/ allergen-induced exacerbation status: non-asthmatics (1) (n = 70)-241.5 (114-564) ng/ml, remission (2) (n = 34)-490 (241-925) ng/ ml, virus-induced exacerbation (3) (n = 5)-604 (540-605) ng/ml, allergen-induced exacerbation (4) (n = 54)-529 (346-1040), p 1,2 = 0.005, p 1,4 = 0.0001. Conclusion: Our data suggest that increased levels of MASP may be associated with asthma severity in children during an exacerbation of the disease and may be used as a new marker of severe asthma, especially in an allergen-induced exacerbation. (Table Presented).
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In this study, a partial-filling affinity capillary electrophoresis (pf-ACE) method was developed for the cross-validation of fragment hits revealed by chromogenic factor XIIa (FXIIa) assay. Chromogenic assay produces false positives, mainly due to spectrophotometric interferences and sample purity issues. pf-ACE was selected as counter-screening technology because of its separative character and the fact that the target does not have to be attached or tagged. The effects of protein plug length, applied voltage and composition of the running buffer were examined and optimized. Detection limit in terms of dissociation constant was estimated at 400 µM. The affinity evaluation was performed close to physiological conditions (pH 7.4, ionic strength 0.13 mol L-1) in a poly (ethylene oxide)-coated capillary of 75 µm internal diameter x 33 cm length with an applied voltage of 3 kV. This method uncovered chromogenic assay's false positives due to zinc contamination. Moreover, pf-ACE supported the evaluation of compounds absorbing at 405 nm.
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Nafamostat, a serine proteinase inhibitor with various actions including antithrombin, antiplasmin, and antitrypsin effects, has been used in clinical practice to treat disseminated intravascular coagulation (DIC) and pancreatitis. This case report describes the clinical course of a patient with COVID-19 pneumonia whose severe hypoxemia, probably caused by DIC and pulmonary embolism, showed remarkable improvement with combination heparin and nafamostat therapy. In addition, beneficial mechanisms of nafamostat against COVID-19 and the necessity of attention to hyperkalemia as an adverse effect are discussed.