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Coronavirus disease 2019 (COVID-19) is a fatal pandemic viral disease caused by the severe acute respiratory syndrome corona virus type-2 (SARS-CoV-2). The aim of this study is to observe the associations of IL-6, SARS-COV-2 viral load (RNAemia), IL- 6 gene polymorphism and lymphocytes and monocytes in peripheral blood with disease severity in COVID-19 patients. This study was carried out from March 2021 to January 2022. RT-PCR positive 84 COVID-19 patients and 28 healthy subjects were enrolled. Blood was collected to detect SARS-COV-2 viral RNA (RNAemia) by rRT-PCR, serum IL-6 level by chemiluminescence method, SNPs of IL-6 by SSP-PCR, immunophenotyping of lymphocytes and monocyte by flow cytometry. Serum IL-6 level (pg/ml) was considerably high among critical patients (102.02 +/- 149.7) compared to severe (67.20 +/- 129.5) and moderate patients (47.04 +/- 106.5) and healthy controls (3.5 +/- 1.8). Serum SARS-CoV-2 nucleic acid positive cases detected mostly in critical patients (39.28%) and was correlated with extremely high IL-6 level and high mortality (R =.912, P < 0.001). Correlation between IL-6 and monocyte was statistically significant with disease severity (severe group, p < 0.001, and 0.867*** and critical group p < 0.001 and 0.887***). In healthy controls, moderate, severe and critically ill COVID-19 patients, IL-6 174G/C (rs 1800795) GG genotype was 82.14%, 89.20%, 67.85% and 53.57% respectively. CC and GC genotype had strong association with severity of COVID-19 when compared with GG genotype. Significant statistical difference found in genotypes between critical and moderate groups (p < 0.001, OR-10.316, CI-3.22-23.86), where CC genotype was associated with COVID-19 severity and mortality. The absolute count of T cell, B cell, NK cell, CD4+ T cells and CD8+ T cells were significantly decreased in critical group compared to healthy, moderate and severe group (P < 0.001). Exhaustion marker CD94/NKG2A was increased on NK cells and CD8+ cytotoxic T cell among critical and severe group. Absolute count of monocyte was significantly increased in critical group (P < 0.001). Serum IL-6, IL-6 174 G/C gene and SARS-CoV-2 RNAaemia can be used in clinical practice for risk assessment;T cell subsets and monocyte as biomarkers for monitoring COVID-19 severity. Monoclonal antibody targeting IL-6 receptor and NKG2A for therapeutics may prevent disease progression and decrease morbidity and mortality.Copyright © 2023 Elsevier Inc.
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Risk and predisposing factors for viral zoonoses abound in the sub-Saharan Africa (SSA) region with significant public health implications. For several decades, there have been several reports on the emergence and re-emergence of arbovirus infections. The lifetime burden of arboviral diseases in developing countries is still poorly understood. Studies indicate significant healthcare disruptions and economic losses attributed to the viruses in resource-poor communities marked by impairment in the performance of daily activities. Arboviruses have reportedly evolved survival strategies to aid their proliferation in favorable niches, further magnifying their public health relevance. However, there is poor knowledge about the viruses in the region. Thus, this review presents a survey of zoonotic arboviruses in SSA, the burden associated with their diseases, management of diseases as well as their prevention and control, mobility and determinants of infections, their vectors, and co-infection with various microorganisms. Lessons learned from the ongoing coronavirus disease 2019 (COVID-19) pandemic coupled with routine surveillance of zoonotic hosts for these viruses will improve our understanding of their evolution, their potential to cause a pandemic, control and prevention measures, and vaccine development.Copyright © GERMS 2022.
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Introduction: SARS-CoV-2 replicates primarily in the airways but generates a systemic immune response mediated by Type I interferons (IFN-I). Pernio is a rare skin manifestation of disorders characterized by excessive IFN-I signalling. Although pernio increased in incidence during the pandemic, the relationship to SARS-CoV-2 remains controversial. Because of the pivotal nature of interferons in COVID-19 outcomes, pernio offers a window to investigate the biology underlying host resiliency to SARS-CoV-2 infection. Method(s): To further assess COVID-associated pernio, we characterized clinical samples from affected patients across 4 waves of the pandemic and investigated mechanistic feasibility in a rodent model. Patients were followed longitudinally with banking of blood and tissue. Golden hamsters were mock-treated or intra-nasally infected with SARS-CoV-2 and harvested at 3-and 30-days post-infection. Result(s): In affected tissue, immunophenotyping utilizing multiplex immunohistochemistry profiled a robust IFN-1 signature characterized by plasmacytoid dendritic cell activation. Viral RNA was detectable in a subset of cases using in situ hybridization for the SARS-CoV-2 S gene transcript. Profiling of the systemic immune response did not reveal a durable type 1 interferon signature. Consistent with previous literature, antibody and T-cell specific responses to SARS-CoV-2 were not detected. Nasopharyngeal SARS-CoV-2 inoculation in hamsters resulted in rapid dissemination of viral RNA and the generation of an IFN-I response that were both detectable in the paws of infected animals. Conclusion(s): Our data support a durable local IFN signature, with direct evidence of viral SARS-CoV-2 RNA in acral skin and suggest that COVID-associated pernio results from an abortive, seronegative SARS-CoV-2 infection.
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Aim. To determine the clinical efficacy and safety of the immobilized (sorbed) probiotics Bifidobacterium bifidum 1 (5x108 CFU) and B. bifidum 1 (5x107 CFU) in combination with Lactobacillus plantarum 8P-A3 (5x107 CFU) in the complex therapy of pneumonia caused by SARS-CoV-2 in adult patients without severe risk factors and their impact on health-related quality of life (QoL). Material and methods. An open, randomized prospective study included 100 patients (45 males, 55 females), aged from18 to 60 years without risk factors for severe COVID-19, with pneumonia confirmed by computed tomography and an area of lung lesion no more than 75% (moderate forms). SARS-CoV-2 RNA in nasal and oropharyngeal swabs (RT-PCR) was detected in 72% of the participants, in the rest it was highiy probable in terms of the aggregate parameters. The publication presents the results of self-assessment (94 respondents) of working capacity limitations, shortness of breath, intestinal disorders since the end of the probiotic regimen (PR: hospitalization period - B. bifidum 1, 3 capsules 2 times a day for 10 days, then after hospitalization - B. bifidum 1 in combination with L. plantarum 8P-A3 2 powders 3 times a day for 14 days) and QoL (Short Form Medical Outcomes Study: SF-36) 1 month after hospitalization. Results. At the end of PR, the ability to engage in daily activities was higher by 23.1% [95% confidence interval 5.3-37.3, OR 0.08 (0.08-0.77)]. Difficulty of breathing during exercise was less common by 29.7% [15.1-44.5%], OR 0.09 [0.02-0.40], hard stools and no bowel movements were recorded less often by 21.3% [8.5-34, 1] for 1-3 days. One month after hospitalization, the QoL of the patients receiving standard treatment was significantly reduced relative to population indicators in Russia. It was more significantly due to the psychological component of health [total measurement 38.1 (36.2-40.0)] and less significantly due to the physical component [49.5 (48.3-50.8)]. The main reasons limiting daily activities [Role Emotional (RE): 39.4 (37.4-41.4)] were decreased vitality [VT: 40.2 (38.9-041.5)], emotional depression [Mental Health (MH): 41.2 (39.4-43.0)], deficit of social contacts [Social Functioning (SF): 45.1 (43.7-46.6)]. The patients who received PR had a higher ability to carry out daily activities [RE: 57.7 (55.6-59.7)], the severity of psychological problems associated with fatigue, anxiety and depression was lower [MH: 59.8 (58.7-60.9), p<0,001]. The effect of the PR on negative perceptions of social isolation was comparatively less [SF: 53.9 (52.2-55.4)]. The QoL of the patients who additionally suffered from diarrhea in the acute period of SARS-CoV-2 pneumonia was worse in comparison with the patients without diarrhea (due to pain and inability to endure physical activity). The effects of immobilized (sorbed) probiotics to the QoL of the patients with diarrhea during the acute period of COVID-19 were most significant. Conclusion. PR had a significant positive effect on the QoL within a month after hospitalization, increasing working capacity and improving mental health, reducing the severity of psychological problems and fatigue. Additional researches are needed on the possible relationship of organic and functional gastrointestinal diseases with the progression of diarrhea in patients infected with SARS-CoV-2. No side effects of the sorbed probiotics regimen have been identified.Copyright © Eco-Vector, 2022.
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Pseudomonas aeruginosa can cause severe nosocomial infections and sepsis, especially in immunocompromised comorbid patients. The purpose of the study was to assess the frequency, clinical course, and the possibility of antimicrobial therapy for bloodstream infections caused by P. aeruginosa in patients with COVID-19. Material and methods. A retrospective single-center uncontrolled study was performed from October 1, 2020 to September 31, 2021 on the basis of a temporary infectious diseases hospital for patients with COVID-19 at the City Clinical Hospital No. 52, Moscow. During the analyzed period, 16 047 patients were admitted to the infectious diseases hospital. The study included 46 patients over 18 years of age with a diagnosis of COVID-19 confirmed by PCR RNA SARS-CoV-2 nasopharyngeal swab (U 07.1) and/or computed tomography (CT) of the lungs (U 07.2). Statistical data processing was carried out using the BioStat, 2009 program (AnalystSoft, USA). Results and discussion. P. aeruginosa has been isolated from the blood of 0.29% of patients with COVID-19. In the structure of bacteremia, P. aeruginosa accounted for 6.1%. In 87% of cases, pathogens were isolated from the blood of patients in the ICU. Most strains are classified as XDR phenotypes - 74% and MDR - 21.7%. The sensitivity of hospital strains of P. aeruginosa was: to colistin - 97%, to amikacin - 39.1%, meropenem - 32.6%. All patients had concomitant diseases: cardiovascular (60%), oncological (27.5%), diabetes mellitus (20%), obesity (22.5%) and others. In 47.5% of cases (19/40), the cause of bloodstream infections was ventilator-associated pneumonia. The mortality rate among patients with COVID-19 with P. aeruginosa bacteremia is 80%. Conclusion. The wide distribution of multidrug-resistant strains of P. aeruginosa limits the number of therapeutic options. In severe bloodstream infections caused by P. aeruginosa XDR, combined antibiotic therapy regimens with the inclusion of polymyxin B are advisable.Copyright © 2022 Tomsk Polytechnic University, Publishing House. All rights reserved.
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Listeriosis is a saprozoonotic infection that occurs when eating foods contaminated with Listeria. Invasive forms of listeriosis can have extremely severe consequences. Respiratory viral diseases predispose to the occurrence of combined viral-bacterial infections. With a mixed infection of listeriosis and COVID-19, a severe course of the disease is observed, which has a serious prognosis. The aim of the study was to analyze the frequency of various variants of invasive listeriosis and their outcomes in the period before the COVID-19 pandemic and against the background of its development, as well as to determine the genetic diversity of L. monocytogenes isolates. Material and methods. We analyzed 55 cases of invasive listeriosis in patients observed in 2018-2021 in various medical organizations in Moscow. The diagnosis was established on the basis of epidemiological, clinical and laboratory data, listeriosis was confirmed by bacteriological and molecular genetic methods, COVID-19 was confirmed by the detection of SARS-CoV-2 RNA in an oropharyngeal swab using real-time RT-PCR, as well as computed tomography of the lungs. Results. During the current COVID-19 pandemic (2020-2021), the incidence of listeriosis in pregnant women and invasive listeriosis occurring in the form of sepsis and/or lesions of the central nervous system did not differ significantly from similar indicators registered in 2018-2019. Listeria sepsis and/or meningitis/meningoencephalitis in association with severe SARS-CoV-2 novel coronavirus infection are at high risk of death. During the years of the COVID-19 pandemic, the diversity and range of L. monocytogenes genotypes in invasive listeriosis changed, new genotypes appeared that were not previously characteristic of the Russian Federation. Conclusion. The likelihood of developing listeriosis sepsis and/or meningitis/meningoencephalitis against the background of a severe course of COVID-19, and a high risk of an adverse outcome, require increased awareness of medical workers in the field of diagnosis and treatment of invasive listeriosis in order to conduct the earliest and most adequate antibiotic therapy.Copyright © 2022 Geotar Media Publishing Group. All Rights Reserved.
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Intro: Deoxyribozymes (Dz) are short synthetic DNA oligonucleotides that catalyze the cleavage of a phosphodiester bond between nucleotides in the presence of divalent metal ions. The use of DNAzymes in the in vitro diagnostics increases the specificity and versatility of the analysis. Method(s): We took the well-studied Dz 10-23 with high catalytic activity as the basis of our system. The biosensor is divided into two fragments according to the binary probe principle (Dz1 and Dz2), which consist of target RNA binding sites, a fluorescent substrate (Fsub), and half of the Dz 10-23 catalytic center sequence. Assembly of the Dz 10-23 active center with subsequent Fsub cleavage and registration of a fluorescent signal is possible only if the target RNA is present in the sample. Finding(s): To assess the diagnostic potential of the biosensor, we measured FAM fluorescence in a solution containing synthetic RNA 35 nucleotides long (nip35) corresponding to the NiV target sequence, Fsub labeled with the FAM-BHQ1 and Dz_NiV pair. A mixture of Dz_NiV and Fsub was used as a control. The detection limit of the target RNA reached 5 nM, the signal development time was 30 minutes at a temperature of 37 C . Discussion(s): The specificity of Dz_NiV was evaluated in the presence of synthetic RNAs from six other RNA viruses of similar length: Hendra, Machupo, Sabia, Junin, Guanarito, and SARS-CoV. A fluorescent signal was recorded only in the presence of nip35 in the reaction mixture. The efficiency of Dz_NiV on a long fragment was tested using a plasmid with a cloned target sequence. The site is about 700 b.p. was amplified by PCR, followed by transcription. Conclusion(s): It was developed the highly specific biosensor Dz_NiV for the detection of Nipah virus RNA with a sensitivity limit of 5 nM at 37 C .Copyright © 2023
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Introduction: Syphilis is a multi-systemic disease caused by spirochete Treponema pallidum. Very rarely, it can affect the liver and cause hepatitis. Since most cases of hepatitis are caused by viral illnesses, syphilitic hepatitis can be missed. Here, we present a case of syphilitic hepatitis in a 35-year-old male. Case Description/Methods: Patient was a 35-year-old male who presented to the hospital for jaundice and mild intermittent right upper quadrant abdominal pain. His medical history was only significant for alcohol abuse. His last drink was 4 weeks ago. He was sexually active with men. On exam, hepatomegaly, mild tenderness in the right upper quadrant, jaundice, and fine macular rash on both hands and feet were noted. Lab tests revealed an ALT of 965 U/L, AST of 404 U/L, ALP of 1056 U/L, total bilirubin of 9.5 mg/dL, direct bilirubin of 6.5 mg/dL, INR of 0.96, and albumin of 2.0 g/dL. Right upper quadrant ultrasound showed an enlarged liver but was negative for gallstones and hepatic vein thrombosis. MRI of the abdomen showed periportal edema consistent with hepatitis without any gallstones, masses, or common bile duct dilation. HIV viral load and Hepatitis C viral RNA were undetectable. Hepatitis A & B serologies were indicative of prior immunization. Hepatitis E serology and SARS-CoV-2 PCR were negative. Ferritin level was 177 ng/mL. Alpha-1-antitrypsin levels and ceruloplasmin levels were normal. Anti-Smooth muscle antibody titers were slightly elevated at 1:80 (Normal < 1:20). Anti-Mitochondrial antibody levels were also slightly elevated at 47.9 units (Normal < 25 units). RPR titer was 1:32 and fluorescent treponemal antibody test was reactive which confirmed the diagnosis of syphilis. Liver biopsy was then performed which showed presence of mixed inflammatory cells without any granulomas which is consistent with other cases of syphilitic hepatitis. Immunohistochemical stain was negative for treponemes. Patient was treated with penicillin and did have Jarisch-Herxheimer reaction. ALT, AST, ALP, and total bilirubin down trended after treatment. Repeat tests drawn exactly 1 month post treatment showed normal levels of ALT, AST, ALP, and total bilirubin (Figure). Discussion(s): Liver damage can occur in syphilis and can easily be missed because of the non-specific nature of presenting symptoms. In our patient, the fine macular rash on both hands and feet along with history of sexual activity with men prompted us to test for syphilis which ultimately led to diagnosis and treatment in a timely manner. (Figure Presented).
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Patients with end-stage chronic kidney disease treated with hemodialysis are at risk of infection and severe course of the new coronavirus infection. This opinion was based on the data obtained as a result of PCR testing during the active phase of the disease with detailed clinical symptoms. However, this diagnostic method does not allow one to fully assess the prevalence of infection in the population. The aim - studying of the frequency of SARS-CoV-2 infection in patients receiving hemodialysis treatment and the spectrum of antiviral antibodies, depending on the nature of the course of COVID-19. Material and methods. 100 patients with chronic kidney disease (stage 5D) treated at the outpatient Dialysis Center (MCVTP) were included in the study by a simple random sample. The assessment of SARS-CoV-2 infection was carried out by analyzing the material of smears obtained from the naso-oropharynx by PCR and blood serum samples by ELISA. The study excluded 14 patients with dubious results for the determination of serological markers SARS-CoV-2 and 1 patient with active infection, who was isolated from the RNA of the virus. Results. IgM and IgG antibodies were detected in 49 (57.6%) of the 85 examined patients. 24 of them (group 1) were diagnosed with COVID-19 infection with typical clinical symptoms 3-9 months ago, and 25 (group 2) had no clinical manifestations of the acute respiratory infection at the appropriate time suggesting an asymptomatic course of the disease. IgM class antibodies were detected with equal frequency in group 1 and in group 2 (33.3 vs 24.0%, respectively, p<0.6). IgG antibodies exclusively to the nucleocapsid N-protein (IgGn) were detected only in the latent form of the disease (32%), while antibodies against the S-protein (spike protein) of the virus (IgGs and IgGn+s) were detected more often in the manifest form compared to the asymptomatic one (100 vs 60%, respectively, p<0.05). Conclusion. In a random cohort of patient receiving hemodialysis treatment, more than half were asymptomatic.Despite a wide range of prevention measures, SARS-CoV-2 infection among patients treated with hemodialysis is more than 2 times higher than in the general population.Copyright © 2021 Geotar Media Publishing Group. All rights reserved.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first detected in December 2019, and shortly after pandemic has been declared by the World Health Organization (WHO) due to its unstoppable global spread. Considerable amount of effort has beenput around the World in order to develop a safe and effective vaccine against SARS-CoV-2. Inactivated and RNA vaccines have already passed phase three studies showing sufficient efficacy and safety, respectively. Nowadays, there is a noticeable dominance of SARS-CoV-2 variants with various mutations over the wild type SARS-CoV-2. However, there is no report showing the efficacy of these vaccines on these variants. This case study describes a thirty-eight-year-old male reported to be infected with SARS-CoV-2 alpha variant following two doses of inactive CoronaVac administration with a protective level of SARS-CoV-2 specific antibodies. The variant analysis of the virus reported to be positive for N501Y mutation.This is the first case in the literature demonstrating that inactive SARS-CoV-2 vaccine might have a lower efficacy on alpha variant.Copyright © 2022 Cenk Serhan Ozverel et al., published by Sciendo.
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Intro: SARS-CoV-2 is a single-strand enveloped RNA virus belonging to the family Coronaviridae. It was first recognized in late 2019 as causing COVID-19, and later declared a pandemic. The development of this assay aided in the detection of positive cases early in the pandemic which in turn facilitated the isolation of infected individuals to minimize the spread. Method(s): The SARS-CoV-2 RNA detection by real time RT-PCR is a molecular in vitro diagnostic test that aids in the detection and diagnosis of SARS-CoV-2 in nasopharyngeal and oropharyngeal specimens. This test is based on nucleic acid extraction and amplification technology and uses oligonucleotide primers and dual-labeled hydrolysis probes. RNA is isolated and purified from specimens using the Abbott m2000sp. This technology uses magnetic particles to capture and purify the RNA. The bound RNA is eluted and transferred to a 96 deep-well plate and is ready for amplification. The master mix is prepared manually and is added to a PCR plate together with the extracted RNA. The RNA is reverse transcribed to cDNA and subsequently amplified in the Abbott m2000rt. In this process, the probe anneals to a specific target sequence located between the forward and reverse primers. During the extension step of the PCR cycle, the 5' nuclease activity of Taq polymerase degrades the probe, causing the reporter dye molecules to be cleaved from their respective probes, increasing the fluorescence intensity. Fluorescence intensity is monitored at each PCR cycle on the Abbott m2000rt instrument. Finding(s): The clinical evaluation was performed by testing patient samples in a blinded fashion. The performance of SARS-CoV-2 Assay was established using 60 clinical specimens. The positive and negative percent agreements were analyzed by comparing the SARS-CoV-2 Assay results to Seegene's AllplexTM 2019-nCoV which showed 100% concordance. Conclusion(s): This assay demonstrated accuracy and reproducibility for the detection of SARS-CoV-2.Copyright © 2023
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The problem of the incidence of new coronavirus infection in childhood is becoming increasingly important. At the same time, questions arise regarding the peculiarities of the pathogenesis of COVID-19 in children. The aim of the research was to study the clinical and immunological features of COVID-19 in children hospitalized with a severe course of the disease. Material and methods. We examined 53 children from 0 to 15 years old, hospitalized with suspected new coronavirus infection at Children's Clinical Hospital No. 3 in Novosibirsk from October to December 2020. Determination of specific IgM and IgG antibodies to SARS-CoV-2 antigens in serum blood was carried out using the ELISA method. SARS-CoV-2 virus RNA in nasopharyngeal and oropharyngeal swabs was determined using commercial kits for PCR diagnostics. A z-test was used to compare relative numbers. The significance level was taken equal to 5% (p=0.05). Results and discussion. All examined children hospitalized with suspected COVID-19, regardless of the duration of the disease, had specific IgG antibodies to SARS-CoV-2 antigens, which confirms earlier contact with the new coronavirus in relation to the time of the examination. In 63.6% of cases, specific IgM antibodies of the class to SARS-CoV-2 were detected in the blood serum, in 6% of cases the result was doubtful. IgM antibodies were not detected in blood serum in 30.3% of patients. The results obtained for the determination of IgG and IgM antibodies to SARS-CoV-2 antigens may reflect the atypical nature of seroconversion in COVID-19. An extremely diverse clinical symptomatology was revealed, including, in addition to catarrhal syndrome and intoxication syndrome, abdominal, meningeal, and articular syndromes. In 24.3% of children, polymorphic exanthema was detected, which may be a manifestation of the systemic nature of damage to the vascular wall. Conclusion. With serologically confirmed SARS-CoV-2 etiology of the infectious process in the examined children, an extremely diverse clinical symptomatology was revealed, which, most likely, may be associated with multiple organ damage.Copyright © Transplantologiya. The Russian Journal of Transplantation.All right reserved.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected more than 600 million people across 219 countries during the past three years. SARS-CoV-2 consists of a positive-strand RNA genome that encodes structural and nonstructural proteins and shares a 79% sequence homology with severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1). Nonstructural proteins are necessary for viral replication and suppression of the host cell immune response. Nonstructural protein 1 (nsp1), a small protein conserved among most beta-coronaviruses, inhibits host messenger RNA (mRNA) translation by binding to ribosomal mRNA channels. Nsp1 also triggers degradation of host mRNA while viral RNA remains intact. We have previously shown that nsp1 localizes within stress granules (SGs), non-membranous vesicles of stalled mRNA that form in response to viral infection. We also found that upon induction of stress, SGs disperses within 60- 120 minutes in the presence of nsp1. Since SGs are known to store and protect translationally stalled mRNAs that are target of nsp1, we sought to analyze the level of mRNAs accumulation in SGs in the presence of nsp1. The goal of this project is to identify the impact of nsp1 on stress granule formation during SARS-CoV infection. We used human embryonic kidney cells (HEK293) and transfected them with DNA expressing SARSCoV- 1 nsp1 or a control plasmid. Cells were then incubated at 37degreeC under 5% CO2 concentration for 16 hours. Following incubation, cells were subjected to 30 min of oxidative stress using sodium arenite. Cells were collected and lysed using lysis buffer, then centrifuge at 18 000xg to collect SG pellets used for RNA isolation. Isolated mRNAs were quantified using quantitative RT-PCR. We specifically targeted mRNAs that tend to show a preferential accumulation in SGs without any viral infection. When nsp1 was expressed, we found majority of mRNAs have shown a 2-fold decrease in accumulation in SGs. These results suggest there is a direct effect of nsp1 in dispersing of RNA from SGs. We are currently investigating the effect of viral leader sequence in their accumulation in SGs in the presence of nsp1. This project was supported by the DRP award from SC INBRE (NIGMS, P20GM103499).Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
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Background: The unprecedented scale of the COVID-19 pandemic and rapid evolution of SARS-CoV-2 variants underscores the need for broadly active inhibitors with a high barrier to resistance. The coronavirus main protease (Mpro) is an essential viral enzyme required for viral polyprotein processing and is highly conserved across human coronaviruses. Pomotrelvir (PBI-0451) is a novel Mpro inhibitor currently completing phase 2 clinical trial. Here we describe the mechanism of action, broad activity against SARS-CoV-2 clinical isolates, combination studies with other SARS-CoV-2 inhibitors and favorable resistance profile of pomotrelvir. Method(s): The kinetic parameters of pomotrelvir Mpro inhibition and its interaction with nirmaltrevir were determined in a kinetic protease assay. The IC50s of pomotrelvir on mutant Mpro proteins were measured in an endpoint Mpro assay. Combination studies of pomotrelvir with remdesivir and molnupiravir were carried out in A549-hACE2 cells infected with SARS-CoV-2 NLuc virus. Activity against SARS-CoV-2 clinical variants was assessed by infection of A549-ACE2-TMPRSS2 cells followed by immunostaining of the viral nucleocapsid protein. Result(s): Pomotrelvir is a potent competitive inhibitor of SARS-CoV-2 Mpro (Ki =2.7 nM). Binding of pomotrelvir and the Mpro inhibitor nirmatrelvir to the active site is mutually exclusive. In the SARS-CoV-2 NLuc assay, pomotrelvir is additive when combined with remdesivir or molnupiravir, two nucleoside analogs targeting viral RNA synthesis. When the effect of Mpro substitutions previously selected in a resistance study of pomotrelvir were analyzed in an enzyme assay, only Mpro-N133H showed a significant increase in IC50 (45-fold). The catalytic efficiency of Mpro-N133H is reduced by 10-fold and the recombinant virus SARSCoV-2 (WA1) -N133H is not viable, suggesting that N133H has lower replicative fitness. Lastly, pomotrelvir exhibits broad activity against all SARS-CoV-2 clinical isolates tested to date, including five omicron variants. Conclusion(s): PBI-0451 is a potent competitive inhibitor of SARS-CoV-2 Mpro and is broadly active against SARS-CoV-2 clinical isolates including omicron variants. Results from inhibitor interaction studies support the potential combination of pomotrelvir with remdesivir and molnupiravir but not nirmatrelvir. Enzymatic characterization of in vitro selected pomotrelvir resistant variants indicates they either confer no resistance or have reduced fitness.
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Background: Implementation of vaccination programmes has had a transformational impact on control of the SARS-CoV-2 pandemic, but the need for effective antiviral drugs remains. Molnupiravir (MPV) targets viral RNA polymerase inhibiting replication via lethal mutagenesis and nirmatrelvir (NTV) is a protease inhibitor boosted with ritonavir when given clinically. This study aimed to assess the virological efficacy of NTV and MPV individually and in combination against the SARS-CoV-2 BA.1 Omicron variant in a K18-hACE2 mouse model. Method(s): K18-hACE2 mice were inoculated intranasally with 103 PFU of SARSCoV-2 BA.1 Omicron (B.1.1.529). After 24 hours, mice were orally dosed q12H, as outlined in Figure 1. At 2, 3, and 4-days post infection mice were sacrificed, and lung samples harvested. Animals were weighed and monitored daily throughout. Subsequently, viral replication in the lung was quantified using qRT-PCR to measure total (N-gene) and sub-genomic (E-gene) viral RNA. Data were normalized to 18S for quantitation. Viral exposures expressed as Areas Under viral load Curves (AUCs) were calculated by the trapezoidal method using mean values at each timepoint. Separate studies in Syrian golden hamsters using individual drugs were also conducted, and total serum IgG was measured by ELISA at 4-days post infection. Result(s): Mice gained weight in all groups post-treatment, with no significant difference between groups. A reduction in lung viral exposure was evident in all treatment groups compared to the vehicle control dosed mice (Figure 1). Coadministration of NTV with MPV displayed a trend towards lower lung viral exposure compared to the vehicle control with ~40-and ~45-fold reduction in AUC for N-and SgE-gene assays, respectively. Dosed individually, NTV and MPV reduced viral exposure 5.7-and 7.7-fold for the N-gene assay, respectively. Differences in total serum IgG concentrations were evident between vehicle and NTV-(34-fold reduction, P=0.018), and MPV-(4.2-fold reduction, P=0.053) treated hamsters. Conclusion(s): These data show virological efficacy of NTV and MPV against the SARS-CoV-2 BA.1 Omicron variant. The combination of NTV and MPV demonstrated a lower viral RNA exposure in the lung than either drug alone, albeit not statistically significant. Initial data indicate potential immune alterations in NTV and MPV dosed hamsters. Studies to clarify the utility of NTV/ MPV combinations and further characterize the impact of antiviral therapy on IgG are warranted.
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The N protein of the SARS-CoV-2 virion is critical for viral genome packaging via RNA binding and regulation of viral transcription at the replication-transcription complex (RTC). The N protein can be divided into five main domains, and the central region is the linker, which is predicted to be primarily disordered and has not been heavily studied. The linker is Serine-Arginine Rich, which is phosphorylated at multiple sites by host kinases during infection, thereby promoting the N protein's role in viral transcription. Phosphorylation is a critical process for the regulation of many cellular processes and can provide recognition sites for binding complexes. In a study that examined the recognition of the SARS-CoV-2 N protein by the human 14-3-3 protein, the linker was found to contain critical phosphosites for 14-3-3 binding. The goals of this project are to determine the structure, dynamics, and RNA interactions of the Serine-Arginine Rich linker region. To accomplish this, we performed Nuclear Magnetic Resonance spectroscopy (NMR) experiments to analyze the structure of the linker region of the N protein and its ability to bind viral RNA. NMR confirms predictions that the linker is not entirely unstructured and it is able to bind RNA. The linker region of the N protein with phosphoserine incorporated at S188 was also examined via an NMR titration experiment with 1-1000 RNA. Compared to wild type, the incorporation of phosphorylation decreases binding. Other biophysical techniques such as Analytical Ultracentrifugation (AUC) and Multi-Angle Light Scattering (MALS) are used to identify the association state of the linker and the size of the resulting protein-RNA complex. We are currently working to biophysically characterize the structure, dynamics, and viral RNA binding ability of a mutation found in the Delta and Omicron variants: the R203M linker, which have been shown to enhance viral infectivity. This work was supported by the NSF EAGER grant NSF/ MCB 2034446 and URSA Engage. Support to facilities includes the Oregon State University NMR Facility funded in part by NIH, HEI Grant 1S10OD018518, and by the M. J. Murdock Charitable Trust grant # 2014162.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
ABSTRACT
Background: Recent SARS-CoV-2 variants of concern (VOCs) have shown a progressive loss of sensitivity to monoclonal antibody therapeutics. Remdesivir (RDV) is a nucleotide analog prodrug that targets the viral RNA-dependent RNA polymerase (RdRp) Nsp12 and is approved to treat COVID-19 in hospitalized and non-hospitalized patients. Nsp12 is highly conserved across VOCs to date and RDV antiviral activity against previous VOCs (Alpha to Omicron BA.1) has been maintained. Here, we conduct a structural analysis of Nsp12 substitutions observed in recent Omicron subvariants (BA.2, BA.2.12.1, BA.4, BA.5 and BA.2.75) and assess RDV antiviral activity against clinical isolates and sitedirected mutants (SDMs) in a replicon system. Method(s): The prevalence of Nsp12 substitutions in Omicron subvariants was evaluated by analysis of sequences from the Global Initiative on Sharing Avian Influenza Data (GISAID) EpiCoV database. Structural analysis of identified substitutions was conducted on a prior cryo-electron microscopy-based model of the replication-transcription complex. Antiviral activity against subvariant clinical isolates was assessed by nucleoprotein ELISA in A549-hACE2-TMPRSS2 cells and by SDMs in the replicon system. Result(s): Genomic analysis of >1.4 million Omicron subvariant sequences revealed unique substitutions in Nsp12 compared to the ancestral WA1 strain. Besides P323L, present in all subvariants, G671S was observed in 95.9% of BA.2.75 sequences, F694Y was observed in <=1.9% of BA.4, BA.5 and BA.2.75 sequences, and Y521C was observed in 1.7% of BA.5 sequences. As anticipated, structural analysis of these substitutions showed no direct interaction with the incoming RDV nucleotide triphosphate or the viral RNA. Phenotyping of clinical isolates of Omicron subvariants BA.2, BA.2.12.1, BA.4, BA.5, and BA.2.75 consistently resulted in mean RDV EC50 values of 24.5 nM (BA.2) to 106.0 nM (BA.5). This represented 0.15-to 0.66-fold changes compared to WA1, indicating no loss of in vitro RDV antiviral activity against these VOCs. P323L, G671S, and F694Y were shown previously to have no impact on RDV antiviral activity. Similarly, the individual substitution Y521C showed no change in RDV susceptibility in the SARS-CoV-2 replicon system. Conclusion(s): RDV retained potent in vitro antiviral activity against all tested Omicron VOCs with potencies comparable to the WA1 isolate. These data support the continued use of RDV in patients infected with Omicron subvariants.
ABSTRACT
Assessment of viral load levels in various biological samples taken from the respiratory tract can be an indicator of an ongoing process of active viral replication and may be used to monitor severe respiratory viral infections. The study of the relationship between SARS-CoV-2 viral load and immunological laboratory parameters is an important step in the search for clinical markers of COVID-19. The aim of this research was to quantify viral load in patients with COVID-19 and to identify the relationship between viral load and changes in the parameters of the cellular component of the immune system. A laboratory examination was carried out on 74 patients diagnosed with COVID-19, they were divided into 3 groups based on the severity of the disease: mild, moderate, severe. Total viral load in clinical samples was determined by the number of SARS-CoV-2 RNA copies per 100 copies of the reference RNaseP gene. A comprehensive assessment of the cellular component of the immune system was performed using flow cytometry and direct monoclonal antibodies, and the IL-6, and C-reactive protein concentrations were determined. We revealed a relationship between the development of serious clinical conditions in the patients with COVID-19, and the levels of viral load. High levels of viral RNA in biological samples correlate with main indicators of the T cell component of the immune system associated with disease severity. In a subgroup of patients with an extremely high viral load, strong positive correlations were found between the relative numbers of cytotoxic lymphocytes (CD3+CD8+), activated T lymphocytes (CD3+HLA-DR+), as well as absolute and relative numbers of activated B lymphocytes and NK cells (CD3-CD25+). Laboratory monitoring of the cellular component of the immune system, along with the assessment of viral loads, should improve early assessment of clinical condition in the patients with COVID-19. Changes in expression levels of activation markers on immune cells can be potentially viewed as indicators of recovery during COVID-19.Copyright © Nikitin Yu.V. et al., 2023 The article can be used under the Creative Commons Attribution 4.0 License.
ABSTRACT
Background: Chemoprophylaxis is a critical tool for many infectious diseases, and in COVID-19 may have particular benefit for vulnerable patients that do not maximally benefit from vaccination. Nafamostat inhibits TMPRSS2, which catalyses a critical cell entry pathway for SARS-CoV-2. This study sought to assess efficacy of intranasal nafamostat against airborne transmission of SARSCoV-2 in Syrian Golden hamsters. Method(s): Male hamsters were intranasally administered water or 5 mg/kg nafamostat in water twice daily for 5 days (sentinels). One day after treatment initiation, sentinels were co-housed with an untreated hamster that was intranasally inoculated with 1 x 104 PFU of Wuhan SARS-CoV-2 (donor). Sentinels were separated from the donor by a perforated divider, allowing airflow between zones but not contact. Hamsters were weighed and throat-swabbed throughout. At day 4, all animals were culled, and lung and nasal turbinates were harvested. N-RNA was quantified relative to 18S-RNA by qPCR. A 2-way ANOVA with Bonferroni correction was applied to compare weight changes in the nafamostat group to those in controls. An unpaired t-test was used to compare viral RNA in lung and nasal turbinate between groups. Result(s): SARS-CoV-2 viral RNA was significantly lower in the nasal turbinates of nafamostat-treated hamsters compared to water-treated controls (P = 0.012;Figure 1). Within the lung, SARS-CoV-2 RNA was undetectable in the nafamostat-treated hamsters, but was detectable in the water-treated controls. Viral RNA was undetectable in the swabs of the nafamostat-treated hamsters at all timepoints, but was quantifiable in the water-treated control group from day 3. Body weight of the nafamostat-treated hamsters was significantly lower (P = < 0.001) than in the water-treated animals throughout. SARS-CoV-2 viral RNA was detectable in the donor hamsters lung, nasal turbinate and swab samples confirming validity of the experiment. Conclusion(s): This study demonstrated a protective effect of intranasal nafamostat against airborne SARS-CoV-2 transmission in Syrian golden hamsters. A phase IIa study of intravenously administered nafamostat yielded no evidence of clinical efficacy in hospitalised patients, but further investigation of intranasally administered nafamostat in a prophylactic setting may be warranted.