The CH24H metabolite, 24HC, blocks viral entry by disrupting intracellular cholesterol homeostasis.

Cholesterol-24-hydroxylase (CH24H or Cyp46a1) is a reticulum-associated membrane protein that plays an irreplaceable role in cholesterol metabolism in the brain and has been well-studied in several neuro-associated diseases in recent years. In the present study, we found that CH24H expression can be induced by several neuroinvasive viruses, including vesicular stomatitis virus (VSV), rabies virus (RABV), Semliki Forest virus (SFV) and murine hepatitis virus (MHV). The CH24H metabolite, 24-hydroxycholesterol (24HC), also shows competence in inhibiting the replication of multiple viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). 24HC can increase the cholesterol concentration in multivesicular body (MVB)/late endosome (LE) by disrupting the interaction between OSBP and VAPA, resulting in viral particles being trapped in MVB/LE, ultimately compromising VSV and RABV entry into host cells. These findings provide the first evidence that brain cholesterol oxidation products may play a critical role in viral infection.

Electronic skin as wireless human-machine interfaces for robotic VR.

The coronavirus pandemic has highlighted the importance of developing intelligent robotics to prevent infectious disease spread. Human-machine interfaces (HMIs) give a chance of interactions between users and robotics, which play a significant role in teleoperating robotics. Conventional HMIs are based on bulky, rigid, and expensive machines, which mainly focus on robots/machines control, but lack of adequate feedbacks to users, which limit their applications in conducting complicated tasks. Therefore, developing closed-loop HMIs with both accurate sensing and feedback functions is extremely important. Here, we present a closed-loop HMI system based on skin-integrated electronics, whose electronics compliantly interface with the whole body for wireless motion capturing and haptic feedback via Bluetooth, Wireless Fidelity (Wi-Fi), and Internet. The integration of visual and haptic VR via skin-integrated electronics together into a closed-loop HMI for robotic VR demonstrates great potentials in noncontact collection of bio samples, nursing infectious disease patients and many others.

Buchwald-Hartwig coupled conjugated microporous polymer for efficient removal COVID-19 antiviral drug famciclovir from waters: Adsorption behavior and mechanism.

The consumption of famciclovir (FCV) has been increased dramatically since the outbreak of coronavirus in 2019, and the pollution and harm of FCV in waters are concerned. Here, by utilizing aryl halides on 2, 4, 6-tris(4-bromophenyl)- 1, 3, 5-triazine (BPT) and primary amine groups on benzidine (BZ), a novel conjugated microporous polymer, namely BPT-BZ-CMP, was synthesized by Buchwald-Hartwig coupling reaction and applied in the removal of FCV from aqueous solution firstly. The synthesized BPT-BZ-CMP were characterized by various methods, including FTIR, SEM, BET, and Zeta-potential. Due to the micropore structure and high specific surface area, it took only 30 min for BPT-BZ-CMP to adsorb FCV to reach an equilibrium, and the maximum adsorption capacity was 347.8 mg·g-1. The Liu and pseudo-second-order kinetic models properly fit the adsorption equilibrium and kinetic data, respectively. The adsorption process was a spontaneous process, and the hydrogen bonding, π-π interaction and C-H···π interaction enhanced the adsorption of FCV on BPT-BZ-CMP. BPT-BZ-CMP maintained a good adsorption capacity after four consecutive adsorption-desorption cycle experiments. This study confirmed the potential of BPT-BZ-CMP as efficient sorbent to remove FCV from aqueous solutions.

Functional metal-organic framework as high-performance adsorbent for selective enrichment of pharmaceutical contaminants in aqueous samples

Facile and sensitive analysis methods for pharmaceutical contaminants in aqueous environment are of vital importance for water safety, especially when large amounts of anti-viral drugs are being used, discharged and accumulated. In this work, we used functional metal-organic framework (MOF) as high-performance adsorbent for selective enrichment of such pharmaceutical contaminants in aqueous samples. The MOF was synthesized via a new synthesis method previously developed by our group and immobilized on paper membrane to be used in solid-phase extraction (SPE) device. Different metal ions were anchored by MOF to screen out the adsorbent with the best affinity. The targets were a potential anti-COVID-19 drug favipiravir, and its structural and functional analogues (ingredients or intermediates, other anti-viral drugs). To deeply understand the adsorption mechanisms, quantum calculation and computational fluid dynamics (CFD) simulation were both applied. The experimental and in-silico results together demonstrated that the as-prepared MOF adsorbent possessed high affinity and fast dynamics. The established SPE-based liquid chromatography (LC) method worked well in the range of 10-1000 ng/mL, with only 3 mg of adsorbent per device and 5 mL sample needed, and no mass spectrometer (MS) included, which was very efficient compared to commercial adsorbents. The results met the current detection needs in the application scenario, and inspirable for later design of well-behaved adsorbents.

Kinetics of IgM and IgG antibody specific to SARS-CoV-2 nucleocapsid and spike proteins

：Objective To study the kinetics of IgM and IgG antibodies based on nucleocapsid（N） and spike（S） protein of SARS-Co V2-in COVID-19 patients. Methods Immunofluorescent kits were used to detect N and S protein specific IgM and IgG antibodies from Jan.21 to Feb.11, 2020 for the 60 hospitalized COVID-19 patients（48 mild, 12 severe cases） with a total of 290 plasma samples collected 9 weeks after the onset of the disease. Results The level of antibodies specific for S protein varied significantly with the course of disease（Ig M from 27.32 to 110.10 TU/ml, IgG from 56.85 to 135.00 TU/ml）, but not for N protein.Higher level of Ig M/Ig G antibodies specific to S protein was observed during the 2-7 week than that to N protein.The seropositive rate of antibodies gradually increased during the early stage of disease.IgM/IgG antibodies specific to N protein changed from 12.50% at the first week to peak level（51.72% and 86.21% respectively） at the 4 th week and those for S protein from 25.00% and 14.58% to 100.00%, and then declined.The seropositive rate of Ig M antibody specific to S protein was higher than that for N protein during 2-8 th week and that for Ig G antibody at 2, 3, 4, 6 and 7 th week.The seropositive rate of Ig G antibody specific to N protein in severe patients at the third week was higher than that in mild patients（100.00% vs 59.52%,χ2=9.67, P=0.001 9）, and the same as to Ig G antibody for S protein at the second week after disease onset（80.00% vs 46.58%, χ2=5.57, P=0.018 2）. Conclusions SARS-Co V2-S protein can induc stronger antibody response than N protein, and the antibody level was related to the severity of the disease.

Determinants of the digital outcome divide in E-learning between rural and urban students: Empirical evidence from the COVID-19 pandemic based on capital theory.

Digital outcome divide, the inequality of the outcomes of exploiting and benefitting from the ICT access and usage, has been raised as a severe concern of the e-learning practices during the COVID-19 pandemic. This study drew on capital theory and related literature and conducted a survey of 492 Chinese middle school students to explore: (1) whether a digital outcome divide exists between rural and urban students under the e-learning condition during the COVID-19 pandemic; (2) if it does, how does students' every form of capital impact the digital outcome divide. Our results revealed several important findings. First, we confirmed the existence of the digital outcome divide between rural and urban students, as rural students reported lower levels of behavioral engagement in e-learning courses compared to their urban peers. Second, we found that differences exist between rural and urban students in habitus (i.e., intrinsic motivation) and forms of capital, including cultural (i.e., e-learning self-efficacy) and social capital (i.e., parental support and teacher support), which are the main causes of the digital outcome divide. Third, a Blinder-Oaxaca decomposition analysis further confirmed that those factors could explain the major parts of the digital outcome divide between urban and rural students and that e-learning self-efficacy, intrinsic motivation, and parental support were the most dominant factors contributing to the rural-urban digital outcome divide in the e-learning context. Our study provides several important theoretical and managerial implications for researchers and educators.

Kinetics of SARS-CoV-2 antibodies in COVID-19 patients and relationship with severity of disease

Objective To study the kinetics of SARS-CoV-2 antibodies in COVID-19 patients and the correlation with disease severity. Methods A total of 290 plasma samples were collected from 60 hospitalized patients including 48 mild cases and 12 severe cases within 63 days after disease onset in Guangzhou Eighth People′s Hospital affiliated to Guangzhou Medical University during January 21 to April 11, 2020.SARS-CoV-2 specific antibodies were determined by four commercial colloidal gold serologic reagents validated by National Medical Products Administration in China. Results The seropositive rate ranged from 19.23% to 34.62% by four assays within one week after disease onset, and rapidly increased within the following two weeks.The seropositive rates were 52.27% to 68.18% and 83.05% to 98.31%, respectively.IgM antibody peaked within the fourth week and maintained high level for 1 to 2 weeks, and decreased significantly until the 9 th week.But no obvious decreasing trend of the seropositive rate of IgG antibody was observed during two months after disease onset.The seropositive rates of antibodies between mild and severe cases showed no statistical difference.Four assays demonstrated a sensitivity of 78.33%to 91.67%in 60 COVID-19 patients.The difference was statistically significant between the highest and the lowest values（χ2=4.183,P=0.041）． Conclusions The colloidal gold serologic reagents show good sensitivity during the late stage of disease but not at the early stage.There is no correlation between seropositive and disease severity.The sensitivity of different reagents is different

PABPC4 Broadly Inhibits Coronavirus Replication by Degrading Nucleocapsid Protein through Selective Autophagy.

Emerging coronaviruses (CoVs) can cause severe diseases in humans and animals, and, as of yet, none of the currently available broad-spectrum drugs or vaccines can effectively control these diseases. Host antiviral proteins play an important role in inhibiting viral proliferation. One of the isoforms of cytoplasmic poly(A)-binding protein (PABP), PABPC4, is an RNA-processing protein, which plays an important role in promoting gene expression by enhancing translation and mRNA stability. However, its function in viruses remains poorly understood. Here, we report that the host protein, PABPC4, could be regulated by transcription factor SP1 and broadly inhibits the replication of CoVs, covering four genera (Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus) of the Coronaviridae family by targeting the nucleocapsid (N) protein through the autophagosomes for degradation. PABPC4 recruited the E3 ubiquitin ligase MARCH8/MARCHF8 to the N protein for ubiquitination. Ubiquitinated N protein was recognized by the cargo receptor NDP52/CALCOCO2, which delivered it to the autolysosomes for degradation, resulting in impaired viral proliferation. In addition to regulating gene expression, these data demonstrate a novel antiviral function of PABPC4, which broadly suppresses CoVs by degrading the N protein via the selective autophagy pathway. This study will shed light on the development of broad anticoronaviral therapies. IMPORTANCE Emerging coronaviruses (CoVs) can cause severe diseases in humans and animals, but none of the currently available drugs or vaccines can effectively control these diseases. During viral infection, the host will activate the interferon (IFN) signaling pathways and host restriction factors in maintaining the innate antiviral responses and suppressing viral replication. This study demonstrated that the host protein, PABPC4, interacts with the nucleocapsid (N) proteins from eight CoVs covering four genera (Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus) of the Coronaviridae family. PABPC4 could be regulated by SP1 and broadly inhibits the replication of CoVs by targeting the nucleocapsid (N) protein through the autophagosomes for degradation. This study significantly increases our understanding of the novel host restriction factor PABPC4 against CoV replication and will help develop novel antiviral strategies.

Research progress on potential application of Gualou Xiebai Banxia decoction in prevention and treatment of COVID-19

Since December 2019, COVID-19 cases have appeared in many parts Ofthe world and the number has soared. The epidemic situation is very serious. With the participation ot'traditional Chinese medicine in China, the epidemic prevention and control effect is remarkable, highlighting the unique advantages of traditional Chinese medicine. The symptoms of severe COVID-19 are very consistent with that of chest discomfort in Chinese medicine. Gualou Xiebai Banxia decoction is the first choice for the treatment of chest discomfort. In the diagnosis and treatment programs of COVID-19 in various provinces and cities, it has been recommended to add or subtracted Gualou Xiebai Banxia decoction. In clinical practice, XiangYang Hospital of Traditional Chinese and Western Medicine has added or subtracted Gualou Xiebai Banxia decoction to cure many patients with COVID-19. The modern pharmacological effects in Gualou Xiebai Banxia decoction are reviewed in this paper. to provide theoretical basis for its prevention and treatment of COVID-19, and to provide clinical reference for the later treatment of COVID-19.

Analysis of prognostic factors of patients with corona virus disease 2019 in Hefei, China

Objective To explore the relationship of prognosis of Corona Virus Disease 2019 (COVID-19) with age and inflammation. Methods The clinical data of 72 patients with COVID-19 in Hefei were collected. The levels of serum C-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT), erythrocyte sedimentation rate (ESR) were measured. The data was stratified and analyzed according to age, gender and severity of the disease. Results Among the elderly patients with COVID- 19, the proportion of the patients with basic diseases and severe disease was significantly higher, and the proportion of healers was significantly lower than that of other age groups (P<0.05). The levels of IL-6 and CRP in the elderly patients with COVID-19 were significantly higher than those in other age groups (P<0.05) . The levels of IL-6 and CRP in the severe patients were significantly higher than those in the mild patients (P< 0.05) . Conclusions Age and inflammation may increase the patients' susceptibility to the new coronavirus, and also adversely affect the patients' prognosis and outcome.

Differential Effects of 17,18-EEQ and 19,20-EDP Combined with Soluble Epoxide Hydrolase Inhibitor t-TUCB on Diet-Induced Obesity in Mice.

17,18-Epoxyeicosatetraenoic acid (17,18-EEQ) and 19,20-epoxydocosapentaenoic acid (19,20-EDP) are bioactive epoxides produced from n-3 polyunsaturated fatty acid eicosapentaenoic acid and docosahexaenoic acid, respectively. However, these epoxides are quickly metabolized into less active diols by soluble epoxide hydrolase (sEH). We have previously demonstrated that an sEH inhibitor, t-TUCB, decreased serum triglycerides (TG) and increased lipid metabolic protein expression in the brown adipose tissue (BAT) of diet-induced obese mice. This study investigates the preventive effects of t-TUCB (T) alone or combined with 19,20-EDP (T + EDP) or 17,18-EEQ (T + EEQ) on BAT activation in the development of diet-induced obesity and metabolic disorders via osmotic minipump delivery in mice. Both T + EDP and T + EEQ groups showed significant improvement in fasting glucose, serum triglycerides, and higher core body temperature, whereas heat production was only significantly increased in the T + EEQ group. Moreover, both the T + EDP and T + EEQ groups showed less lipid accumulation in the BAT. Although UCP1 expression was not changed, PGC1α expression was increased in all three treated groups. In contrast, the expression of CPT1A and CPT1B, which are responsible for the rate-limiting step for fatty acid oxidation, was only increased in the T + EDP and T + EEQ groups. Interestingly, as a fatty acid transporter, CD36 expression was only increased in the T + EEQ group. Furthermore, both the T + EDP and T + EEQ groups showed decreased inflammatory NFκB signaling in the BAT. Our results suggest that 17,18-EEQ or 19,20-EDP combined with t-TUCB may prevent high-fat diet-induced metabolic disorders, in part through increased thermogenesis, upregulating lipid metabolic protein expression, and decreasing inflammation in the BAT.

The Pathogenic Features of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): Possible Mechanisms for Immune Evasion?

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is a newly emerging, highly transmitted and pathogenic coronavirus that has caused global public health events and economic crises. As of March 4, 2021, more than 100 million people have been infected, more than 2 million deaths have been reported worldwide, and the numbers are continuing to rise. To date, a specific drug for this lethal virus has not been developed to date, and very little is currently known about the immune evasion mechanisms of SARS-CoV-2. The aim of this review was to summarize and sort dozens of published studies on PubMed to explore the pathogenic features of SARS-CoV-2, as well as the possible immune escape mechanisms of this virus.

Nomogram for prediction of fatal outcome in patients with severe COVID-19: a multicenter study.

BACKGROUND: To develop an effective model of predicting fatal outcomes in the severe coronavirus disease 2019 (COVID-19) patients. METHODS: Between February 20, 2020 and April 4, 2020, consecutive confirmed 2541 COVID-19 patients from three designated hospitals were enrolled in this study. All patients received chest computed tomography (CT) and serological examinations at admission. Laboratory tests included routine blood tests, liver function, renal function, coagulation profile, C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), and arterial blood gas. The SaO2 was measured using pulse oxygen saturation in room air at resting status. Independent high-risk factors associated with death were analyzed using Cox proportional hazard model. A prognostic nomogram was constructed to predict the survival of severe COVID-19 patients. RESULTS: There were 124 severe patients in the training cohort, and there were 71 and 76 severe patients in the two independent validation cohorts, respectively. Multivariate Cox analysis indicated that age ≥ 70 years (HR = 1.184, 95% CI 1.061-1.321), panting (breathing rate ≥ 30/min) (HR = 3.300, 95% CI 2.509-6.286), lymphocyte count < 1.0 × 109/L (HR = 2.283, 95% CI 1.779-3.267), and interleukin-6 (IL-6) >  10 pg/ml (HR = 3.029, 95% CI 1.567-7.116) were independent high-risk factors associated with fatal outcome. We developed the nomogram for identifying survival of severe COVID-19 patients in the training cohort (AUC = 0.900, 95% CI 0.841-0.960, sensitivity 95.5%, specificity 77.5%); in validation cohort 1 (AUC = 0.811, 95% CI 0.763-0.961, sensitivity 77.3%, specificity 73.5%); in validation cohort 2 (AUC = 0.862, 95% CI 0.698-0.924, sensitivity 92.9%, specificity 64.5%). The calibration curve for probability of death indicated a good consistence between prediction by the nomogram and the actual observation. The prognosis of severe COVID-19 patients with high levels of IL-6 receiving tocilizumab were better than that of those patients without tocilizumab both in the training and validation cohorts, but without difference (P = 0.105 for training cohort, P = 0.133 for validation cohort 1, and P = 0.210 for validation cohort 2). CONCLUSIONS: This nomogram could help clinicians to identify severe patients who have high risk of death, and to develop more appropriate treatment strategies to reduce the mortality of severe patients. Tocilizumab may improve the prognosis of severe COVID-19 patients with high levels of IL-6.

Redefining Cardiac Biomarkers in Predicting Mortality of Inpatients With COVID-19.

The prognostic power of circulating cardiac biomarkers, their utility, and pattern of release in coronavirus disease 2019 (COVID-19) patients have not been clearly defined. In this multicentered retrospective study, we enrolled 3219 patients with diagnosed COVID-19 admitted to 9 hospitals from December 31, 2019 to March 4, 2020, to estimate the associations and prognostic power of circulating cardiac injury markers with the poor outcomes of COVID-19. In the mixed-effects Cox model, after adjusting for age, sex, and comorbidities, the adjusted hazard ratio of 28-day mortality for hs-cTnI (high-sensitivity cardiac troponin I) was 7.12 ([95% CI, 4.60-11.03] P<0.001), (NT-pro)BNP (N-terminal pro-B-type natriuretic peptide or brain natriuretic peptide) was 5.11 ([95% CI, 3.50-7.47] P<0.001), CK (creatine phosphokinase)-MB was 4.86 ([95% CI, 3.33-7.09] P<0.001), MYO (myoglobin) was 4.50 ([95% CI, 3.18-6.36] P<0.001), and CK was 3.56 ([95% CI, 2.53-5.02] P<0.001). The cutoffs of those cardiac biomarkers for effective prognosis of 28-day mortality of COVID-19 were found to be much lower than for regular heart disease at about 19%-50% of the currently recommended thresholds. Patients with elevated cardiac injury markers above the newly established cutoffs were associated with significantly increased risk of COVID-19 death. In conclusion, cardiac biomarker elevations are significantly associated with 28-day death in patients with COVID-19. The prognostic cutoff values of these biomarkers might be much lower than the current reference standards. These findings can assist in better management of COVID-19 patients to improve outcomes. Importantly, the newly established cutoff levels of COVID-19-associated cardiac biomarkers may serve as useful criteria for the future prospective studies and clinical trials.

Prokaryotic expression, purification and antiserum preparation of severe acute respiratory syndrome coronavirus 2 nucleocapsid protein

Objective To express and purify the recombinant nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and prepare antiserum from immunized mice. Methods The prokaryotic plasmid pET28a-N containing SARS-CoV-2 N gene was transformed into Escherichia coli BL21 (DE3). The expression of recombinant SARS-CoV-2 N protein was induced by isopropyl-β-D-thiogalactopyranoside. The Ni-NTA affinity chromatography column was used to purify the recombinant SARS-CoV-2 N protein, and antiserum was obtained from the BALB/c mice immunized with recombinant SARS-CoV-2 N protein combined with manganese adjuvant through intramuscular and subcutaneous injections. The reactions of recombinant SARS-CoV-2 N protein with SARS-CoV-2 N monoclonal antibodies and severe acute respiratory syndrome coronavirus (SARS-CoV) N polyclonal antibodies were detected by Western blotting. The reaction of mouse antiserum with the recombinant SARS-CoV-2 N protein expressed in the cells transfected with eukaryotic expression plasmid was examined by indirect immunofluorescence assay. Results The recombinant SARS-CoV-2 N protein was successfully induced and expressed as a soluble protein with a molecular weight of about 55 000. High concentration of purified protein was obtained. The results of Western blotting showed that the recombinant SARS-CoV-2 N protein could be specifically recognized by the SARS-CoV-2 N monoclonal antibodies and the SARS-CoV N polyclonal antibodies. The prepared mouse antiserum could also correctly recognize the recombinant SARS-CoV-2 N protein expressed in mammalian cells by indirect immunofluorescence assay. Conclusion Recombinant SARS-CoV-2 N protein has been successfully expressed and purified from the prokaryotic expression system, and mouse antiserum has been prepared, which lays a foundation for establishing a rapid SARS-CoV-2 diagnostic tool and further studying the function of SARS-CoV-2 N protein..

Analysis of amino acid variations of major proteins from severe acute respiratory syndrome coronavirus 2

Objective To identify key amino acid variations of major proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by biophysical methods. Methods Through amino acid sequence alignment, classification of variant amino acid residues, three-dimensional structure reconstruction of proteins, and electrostatic interaction analysis of amino acid residues, the key amino acid variations of major proteins from SARS-CoV-2 was analyzed with RaTG13, the bat coronavirus with the highest homology, as the reference. Results At least ten amino acid variations that affect the possible electrostatic interactions were identified in RNA-dependent RNA polymerase (RdRp), exoribonuclease (ExoN), uridylate-specific endoribonuclease (NendoU), and spike (S) protein from SARS-CoV-2. These variations may affect the spatial conformation and biological functions of the proteins. Conclusion The key amino acid variations of the major proteins from SARS-CoV-2 have been preliminarily identified, providing clues for understanding the genetic, pathogenic and epidemiological characteristics of the virus..