Characterization of RNA G-quadruplexes in porcine epidemic diarrhea virus genome and the antiviral activity of G-quadruplex ligands.

Porcine epidemic diarrhea virus (PEDV), an enteropathogenic coronavirus, has catastrophic impacts on the global pig industry. However, there are still no anti-PEDV drugs with accurate targets. G-quadruplexes (G4s) are non-canonical secondary structures formed within guanine-rich regions of DNA or RNA, and have attracted great attention as potential targets for antiviral strategy. In this study, we reported two putative G4-forming sequences (PQS) in S and Nsp5 genes of PEDV genome based on bioinformatic analysis, and identified that S-PQS and Nsp5-PQS were enabled to fold into G4 structure by using circular dichroism spectroscopy and fluorescence turn-on assay. Furthermore, we verified that both S-PQS and Nsp5-PQS PQS could form G4 structure in live cells by immunofluorescence microscopy. In addition, G4-specific compounds, such as TMPyP4 and PDS, could significantly inhibit transcription, translation and proliferation of PEDV in vitro. Importantly, these compounds exert antiviral activity at the post-entry step of PEDV infection cycle, by inhibiting viral genome replication and protein expression. Lastly, we demonstrated that TMPyP4 can inhibit reporter gene expression by targeting G4 structure in Nsp5. Taken together, these findings not only reinforce the presence of viral G-quadruplex sequences in PEDV genome but also provide new insights into developing novel antiviral drugs targeting PEDV RNA G-quadruplexes.

Identification of niclosamide as a novel antiviral agent against porcine epidemic diarrhea virus infection by targeting viral internalization.

Porcine epidemic diarrhea virus (PEDV), an enteropathogenic coronavirus, has catastrophic impacts on the global pig industry. However, there remain no effective drugs against PEDV infection. In this study, we utilized a recombinant PEDV expressing renilla luciferase (PEDV-Rluc) to screen potential anti-PEDV agents from an FDA-approved drug library in Vero cells. Four compounds were identified that significantly decreased luciferase activity of PEDV-Rluc. Among them, niclosamide was further characterized because it exhibited the most potent antiviral activity with the highest selectivity index. It can efficiently inhibit viral RNA synthesis, protein expression and viral progeny production of classical and variant PEDV strains in a dose-dependent manner. Time of addition assay showed that niclosamide exhibited potent anti-PEDV activity when added simultaneously with or after virus infection. Furthermore, niclosamide significantly inhibited the entry stage of PEDV infection by affecting viral internalization rather than viral attachment to cells. In addition, a combination with other small molecule inhibitors of endosomal acidification enhanced the anti-PEDV effect of niclosamide in vitro. Taken together, these findings suggested that niclosamide is a novel antiviral agent that might provide a basis for the development of novel drug therapies against PEDV and other related pathogenic coronavirus infections.

The tyrosine phosphatase PTPN14 inhibits the activation of STAT3 in PEDV infected Vero cells.

Protein tyrosine phosphatase non-receptor type 14 (PTPN14) is a member of the protein tyrosine phosphatase (PTP) family which is a potential tumor suppressor. PTPs modulate the cellular level of tyrosine phosphorylation under normal and pathological conditions. Porcine epidemic diarrhea virus (PEDV) is one of the most important pathogens in the swine industry. Our previous membrane proteomics results showed that PTPN14 was markedly upregulated in PEDV-infected Vero cells. However, its biological roles in PEDV infection have not yet been investigated. In this study, we reported PTPN14 functions as a novel regulator of signal transducer and activator of transcription 3 (STAT3) phosphorylation during PEDV infection. Firstly, PTPN14 was markedly upregulated in PEDV-infected Vero cells with the decrease of STAT3 phosphorylation. Knockdown of PTPN14 or phosphatase inhibitor treatment promoted PEDV proliferation and increased the phosphorylation of STAT3 in Vero cells. On the contrary, overexpression of PTPN14 inhibits viral infection in Vero cells. Moreover, dephosphorylation of STAT3 by PTPN14 might occur in the cytoplasm but not in nucleus. Collectively, our results indicate that PTPN14 plays a negative role in regulating STAT3 activation in PEDV infected Vero cells and demonstrate another layer of regulation in PEDV infection.

Aging Immune System and Its Correlation With Liability to Severe Lung Complications.

Aging is considered to be a decline in physical and physiological events that extensively affect the body's immunity, and is linked with deterioration in both innate and adaptive immune responses. The immune system exhibits profound age-associated variations, known as immunosenescence, comprising a significantly low production of B and T lymphocytes in bone marrow and thymus, a decreased function of mature lymphocytes in secondary lymphoid tissues, a decrease in the synthesis of fresh naïve T cells, and reduced activation of T cells. Elderly individuals face a greater risk for many diseases particularly respiratory diseases due to their poor response to immune challenges as vigorously as the young. The current review explored the aging immune system, highlight the mortality rates of severe lung complications, such as pneumonia, COVID-19, asthma, COPD, lung cancer, IPF, and acute lung injury, and their correlation with aging immunity. This study can be helpful in better understanding the pathophysiology of aging, immune responses, and developing new approaches to improve the average age of the elderly population.

One-year follow-up of chest CT findings in patients after SARS-CoV-2 infection.

BACKGROUND: Knowledge about the 1-year outcome of COVID-19 is limited. The aim of this study was to follow-up and evaluate lung abnormalities on serial computed tomography (CT) scans in patients with COVID-19 after hospital discharge. METHODS: A prospective cohort study of patients with COVID-19 from the First Affiliated Hospital, Zhejiang University School of Medicine was conducted, with assessments of chest CT during hospitalization and at 2 weeks, 1 month, 3 months, 6 months, and 1 year after hospital discharge. Risk factors of residual CT opacities and the influence of residual CT abnormalities on pulmonary functions at 1 year were also evaluated. RESULTS: A total of 41 patients were followed in this study. Gradual recovery after hospital discharge was confirmed by the serial CT scores. Around 47% of the patients showed residual aberration on pulmonary CT with a median CT score of 0 (interquartile range (IQR) of 0-2) at 1 year after discharge, with ground-glass opacity (GGO) with reticular pattern as the major radiologic pattern. Patients with residual radiological abnormalities were older (p = 0.01), with higher rate in current smokers (p = 0.04), higher rate in hypertensives (p = 0.05), lower SaO2 (p = 0.004), and higher prevalence of secondary bacterial infections during acute phase (p = 0.02). Multiple logistic regression analyses indicated that age was a risk factor associated with residual radiological abnormalities (OR 1.08, 95% CI 1.01-1.15, p = 0.02). Pulmonary functions of total lung capacity (p = 0.008) and residual volume (p < 0.001) were reduced in patients with residual CT abnormalities and were negatively correlated with CT scores. CONCLUSION: During 1-year follow-up after discharge, COVID-19 survivors showed continuous improvement on chest CT. However, residual lesions could still be observed and correlated with lung volume parameters. The risk of developing residual CT opacities increases with age.

Clinical efficacy of methylprednisolone and the combined use of lopinavir/ritonavir with arbidol in treatment of coronavirus disease 2019.

This study aims to comparatively analyze the therapeutic efficacy upon multiple medication plans over lopinavir/ritonavir (LPV/r), arbidol (ARB), and methylprednisolone on patients with coronavirus disease 2019 (COVID-19). Totally, 75 COVID-19 patients admitted to The First Affiliated Hospital, Zhejiang University School of Medicine from January 22, 2020 to February 29, 2020 were recruited and grouped based on whether or not LPV/r and ARB were jointly used and whether or not methylprednisolone was used. Indexes including body temperature, time for nucleic acid negative conversion, hospital stays, and laboratory indexes were examined and compared. For all patients, there were no significant differences in the change of body temperature, the time for negative conversion, and hospital stays whether LPV/r and ARB were jointly used or not. While for severe and critically severe patients, methylprednisolone noticeably reduced the time for negative conversion. Meanwhile, the clinical efficacy was superior on patients receiving methylprednisolone within 3 days upon admission, and the duration of hospital stays was much shorter when methylprednisolone was given at a total dose of 0-400 mg than a higher dose of >400 mg if all patients received a similar dose per day. Nonetheless, no significant changes across hepatic, renal, and myocardial function indexes were observed. LPV/r combined with ARB produced no noticeably better effect on COVID-19 patients relative to the single-agent treatment. Additionally, methylprednisolone was efficient in severe and critically severe cases, and superior efficacy could be realized upon its early, appropriate, and short-term application.

Safety of protease inhibitors and Arbidol for SARS-CoV-2 pneumonia in Zhejiang Province, China.

The aim of this study was to evaluate the safety of an antiviral regimen of protease inhibitors combined with Arbidol (umifenovir) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia patients. The genomic sequence of SARS-CoV-2 is highly homologous to that of SARS-CoV (Zhou et al., 2020). Previously published basic and clinical research on anti-SARS-CoV treatment found that lopinavir/ritonavir (LPV/r) could improve the prognosis of SARS patients (Chan et al., 2003; Chu et al., 2004). Darunavir (DRV) is another protease inhibitor that blocks the binding of SARS-CoV-2 to human angiotensin-converting enzyme 2 (Omotuyi et al., 2020). The broad-spectrum antiviral drug Arbidol (umifenovir) also shows in vitro anti-SARS-CoV activity (Khamitov et al., 2008).

Risk factors and clinical features of deterioration in COVID-19 patients in Zhejiang, China: a single-centre, retrospective study.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection swept through Wuhan and spread across China and overseas beginning in December 2019. To identify predictors associated with disease progression, we evaluated clinical risk factors for exacerbation of SARS-CoV-2 infection. METHODS: A retrospective analysis was used for PCR-confirmed COVID-19 (coronavirus disease 2019)-diagnosed hospitalized cases between January 19, 2020, and February 19, 2020, in Zhejiang, China. We systematically analysed the clinical characteristics of the patients and predictors of clinical deterioration. RESULTS: One hundred patients with COVID-19, with a median age of 54 years, were included. Among them, 49 patients (49%) had severe and critical disease. Age ([36-58] vs [51-70], P = 0.0001); sex (49% vs 77.6%, P = 0.0031); Body Mass Index (BMI) ([21.53-25.51] vs [23.28-27.01], P = 0.0339); hypertension (17.6% vs 57.1%, P < 0.0001); IL-6 ([6.42-30.46] vs [16.2-81.71], P = 0.0001); IL-10 ([2.16-5.82] vs [4.35-9.63], P < 0.0001); T lymphocyte count ([305-1178] vs [167.5-440], P = 0.0001); B lymphocyte count ([91-213] vs [54.5-163.5], P = 0.0001); white blood cell count ([3.9-7.6] vs [5.5-13.6], P = 0.0002); D2 dimer ([172-836] vs [408-953], P = 0.005), PCT ([0.03-0.07] vs [0.04-0.15], P = 0.0039); CRP ([3.8-27.9] vs [17.3-58.9], P < 0.0001); AST ([16, 29] vs [18, 42], P = 0.0484); artificial liver therapy (2% vs 16.3%, P = 0.0148); and glucocorticoid therapy (64.7% vs 98%, P < 0.0001) were associated with the severity of the disease. Age and weight were independent risk factors for disease severity. CONCLUSION: Deterioration among COVID-19-infected patients occurred rapidly after hospital admission. In our cohort, we found that multiple factors were associated with the severity of COVID19. Early detection and monitoring of these indicators may reduce the progression of the disease. Removing these factors may halt the progression of the disease. In addition, Oxygen support, early treatment with low doses of glucocorticoids and artificial liver therapy, when necessary, may help reduce mortality in critically ill patients.

Factors Associated With Prolonged Viral RNA Shedding in Patients with Coronavirus Disease 2019 (COVID-19).

BACKGROUND: An outbreak of coronavirus disease 2019 (COVID-19) is becoming a public health emergency. Data are limited on the duration and host factors related to viral shedding. METHODS: In this retrospective study, risk factors associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA shedding were evaluated in a cohort of 113 symptomatic patients from 2 hospitals outside Wuhan. RESULTS: The median (interquartile range) duration of SARS-CoV-2 RNA detection was 17 (13-22) days as measured from illness onset. When comparing patients with early (<15 days) and late (≥15 days after illness onset) viral RNA clearance, prolonged SARS-CoV-2 RNA shedding was associated with male sex (P = .009), old age (P = .033), concomitant hypertension (P = .009), delayed admission to hospital after illness onset (P = .001), severe illness at admission (P = .049), invasive mechanical ventilation (P = .006), and corticosteroid treatment (P = .025). Patients with longer SARS-CoV-2 RNA shedding duration had slower recovery of body temperature (P < .001) and focal absorption on radiograph images (P < .001) than patients with early SARS-CoV-2 RNA clearance. Male sex (OR, 3.24; 95% CI, 1.31-8.02), delayed hospital admission (OR, 1.30; 95% CI, 1.10-1.54), and invasive mechanical ventilation (OR, 9.88; 95% CI, 1.11-88.02) were independent risk factors for prolonged SARS-CoV-2 RNA shedding. CONCLUSIONS: Male sex, delayed admission to hospital after illness onset, and invasive mechanical ventilation were associated with prolonged SARS-CoV-2 RNA shedding. Hospital admission and general treatments should be started as soon as possible in symptomatic COVID-19 patients, especially male patients.

Effect of Corticosteroid Therapy on the Duration of SARS-CoV-2 Clearance in Patients with Mild COVID-19: A Retrospective Cohort Study.

INTRODUCTION: In December, 2019, an outbreak of the coronavirus disease 2019 (COVID-19), which was caused by a novel coronavirus, started in Wuhan, China. So far, there is limited clinical evidence on the effect of corticosteroid therapy for this disease. This study aims to investigate the association between corticosteroid therapy and the duration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clearance among patients with mild COVID-19. METHODS: Patients with mild COVID-19 were enrolled from two medical centers in China between January 13, 2020 and February 29, 2020. Baseline characteristics and durations of RNA clearance were compared between the corticosteroid and non-corticosteroid therapy groups. The independent effects of corticosteroid therapy on the duration of RNA clearance were estimated by generalized linear models. RESULTS: Of 82 patients with a mild infection, 40 patients were male (48.8%), with a median age of 49 years (interquartile range, IQR 36-61). Among those patients, 36 patients (43.9%) received corticosteroid therapy. The adjusted multivariate models showed that the effects of corticosteroids were non-significant on the durations of onset to first RNA clearance [ß 2.48, 95% CI (95% confidence interval) - 0.42 to 5.38, P = 0.0926] and to persistent RNA clearance (ß 1.54, 95% CI - 1.41 to 4.48, P = 0.3016), and durations of therapy to first RNA clearance (ß 2.16, 95% CI - 0.56 to 4.89, P = 0.1184) and to persistent RNA clearance (ß 1.22, 95% CI - 1.52 to 3.95, P = 0.3787). CONCLUSIONS: Corticosteroid therapy in patients with mild COVID-19 was not associated with the duration of SARS-CoV-2 clearance, suggesting that the use of corticosteroids may not be beneficial for patients with mild COVID-19 and should be prudently recommended in clinical practice. However, further studies are needed to verify the findings.

A Deep Learning System to Screen Novel Coronavirus Disease 2019 Pneumonia.

The real-time reverse transcription-polymerase chain reaction (RT-PCR) detection of viral RNA from sputum or nasopharyngeal swab had a relatively low positive rate in the early stage of coronavirus disease 2019 (COVID-19). Meanwhile, the manifestations of COVID-19 as seen through computed tomography (CT) imaging show individual characteristics that differ from those of other types of viral pneumonia such as influenza-A viral pneumonia (IAVP). This study aimed to establish an early screening model to distinguish COVID-19 from IAVP and healthy cases through pulmonary CT images using deep learning techniques. A total of 618 CT samples were collected: 219 samples from 110 patients with COVID-19 (mean age 50 years; 63 (57.3%) male patients); 224 samples from 224 patients with IAVP (mean age 61 years; 156 (69.6%) male patients); and 175 samples from 175 healthy cases (mean age 39 years; 97 (55.4%) male patients). All CT samples were contributed from three COVID-19-designated hospitals in Zhejiang Province, China. First, the candidate infection regions were segmented out from the pulmonary CT image set using a 3D deep learning model. These separated images were then categorized into the COVID-19, IAVP, and irrelevant to infection (ITI) groups, together with the corresponding confidence scores, using a location-attention classification model. Finally, the infection type and overall confidence score for each CT case were calculated using the Noisy-OR Bayesian function. The experimental result of the benchmark dataset showed that the overall accuracy rate was 86.7% in terms of all the CT cases taken together. The deep learning models established in this study were effective for the early screening of COVID-19 patients and were demonstrated to be a promising supplementary diagnostic method for frontline clinical doctors.

Decreased B Cells on Admission Associated With Prolonged Viral RNA Shedding From the Respiratory Tract in Coronavirus Disease 2019: A Case-Control Study.

The viral RNA shedding time (VST) for severe acute respiratory syndrome coronavirus 2 has not been well characterized. Clinical data were collected and compared between patients with short and long VSTs (in the lower and upper quartiles, respectively). The probability of recurrent positive reverse-transcription polymerase chain reaction results decreased sharply to 4.8% after 3 consecutive negative results. A series of ≥3 consecutive negative results was suitable as a criterion for the end of viral RNA shedding. The VST for shedding from the respiratory tract was significantly shorter in patients with normal B-cell counts on admission than in those with decreased B-cell counts (median [interquartile range], 11 [9-13] vs 16 [12-20] days, respectively; P = .001).

Epidemiological, clinical and virological characteristics of 74 cases of coronavirus-infected disease 2019 (COVID-19) with gastrointestinal symptoms.

OBJECTIVE: The SARS-CoV-2-infected disease (COVID-19) outbreak is a major threat to human beings. Previous studies mainly focused on Wuhan and typical symptoms. We analysed 74 confirmed COVID-19 cases with GI symptoms in the Zhejiang province to determine epidemiological, clinical and virological characteristics. DESIGN: COVID-19 hospital patients were admitted in the Zhejiang province from 17 January 2020 to 8 February 2020. Epidemiological, demographic, clinical, laboratory, management and outcome data of patients with GI symptoms were analysed using multivariate analysis for risk of severe/critical type. Bioinformatics were used to analyse features of SARS-CoV-2 from Zhejiang province. RESULTS: Among enrolled 651 patients, 74 (11.4%) presented with at least one GI symptom (nausea, vomiting or diarrhoea), average age of 46.14 years, 4-day incubation period and 10.8% had pre-existing liver disease. Of patients with COVID-19 with GI symptoms, 17 (22.97%) and 23 (31.08%) had severe/critical types and family clustering, respectively, significantly higher than those without GI symptoms, 47 (8.14%) and 118 (20.45%). Of patients with COVID-19 with GI symptoms, 29 (39.19%), 23 (31.08%), 8 (10.81%) and 16 (21.62%) had significantly higher rates of fever >38.5°C, fatigue, shortness of breath and headache, respectively. Low-dose glucocorticoids and antibiotics were administered to 14.86% and 41.89% of patients, respectively. Sputum production and increased lactate dehydrogenase/glucose levels were risk factors for severe/critical type. Bioinformatics showed sequence mutation of SARS-CoV-2 with m6A methylation and changed binding capacity with ACE2. CONCLUSION: We report COVID-19 cases with GI symptoms with novel features outside Wuhan. Attention to patients with COVID-19 with non-classic symptoms should increase to protect health providers.