Comparison and implications of the carbonaceous fractions under different environments in polluted central plains in China: Insight from the lockdown of COVID-19 outbreak☆

Before and during the COVID-19 outbreak in the heated winter season of 2019, the carbonaceous fractions including organic carbon (OC), elemental carbon (EC), OC1–4, and EC1–5 were investigated between normal (November 1, 2019, to January 24, 2020) and lockdown (January 25, to February 29, 2020) periods in polluted regions of northern Henan Province. In comparison to urban site, four rural sites showed higher concentrations of carbonaceous components, especially secondary OC (SOC);the concentration of SOC in rural sites was 1.5–3.4 times that in the urban site. During the lockdown period, SOC in urban site decreased slightly, while it increased significantly in rural sites. NO2 has a significant effect on SOC generation, particularly in normal period when NO2 concentrations were high. Nevertheless, NO2 significantly decreased, and the elevated O3 (increased by 103–138%) contributed considerably to the generation of SOC during lockdown. Relative humidity (RH) promoted SOC production when RH was below 60%, but SOC was negatively correlated or uncorrelated with RH when RH exceeded 60%. Additionally, RH has a more pronounced effect on SOC during lockdown. The contribution of gasoline vehicle emissions decreases significantly in both urban and rural sites (3–12%) due to the significant reduction of anthropogenic activities during lockdown, although the urban site remained with the biggest contributions (37%). These results provide innovative insights into the variations in carbonaceous aerosols and SOC generation during the unique time when anthropogenic sources were significantly reduced and illustrate the differences in pollution characteristics and sources of carbonaceous fractions in different environments. Graphical Image 1

PCIF1-mediated deposition of 5'-cap N6,2'-O-dimethyladenosine in ACE2 and TMPRSS2 mRNA regulates susceptibility to SARS-CoV-2 infection.

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to be a major health problem worldwide. Due to the fast emergence of SARS-CoV-2 variants, understanding the molecular mechanisms of viral pathogenesis and developing novel inhibitors are essential and urgent. Here, we investigated the potential roles of N6,2'-O-dimethyladenosine (m6Am), one of the most abundant modifications of eukaryotic messenger ribonucleic acid (mRNAs), in SARS-CoV-2 infection of human cells. Using genome-wide m6Am-exo-seq, RNA sequencing analysis, and Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing, we demonstrate that phosphorylated C-terminal domain (CTD)-interacting factor 1 (PCIF1), a cap-specific adenine N6-methyltransferase, plays a major role in facilitating infection of primary human lung epithelial cells and cell lines by SARS-CoV-2, variants of concern, and other coronaviruses. We show that PCIF1 promotes infection by sustaining expression of the coronavirus receptors angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) via m6Am-dependent mRNA stabilization. In PCIF1-depleted cells, both ACE2/TMPRSS2 expression and viral infection are rescued by re-expression of wild-type, but not catalytically inactive, PCIF1. These findings suggest a role for PCIF1 and cap m6Am in regulating SARS-CoV-2 susceptibility and identify a potential therapeutic target for prevention of infection.

Coping and post-traumatic stress disorder symptoms among Chinese youth in the peak and remission periods of COVID-19.

The COVID-19 pandemic has exposed emergent vulnerability to adolescents' mental health. This longitudinal study investigated the association between coping at the peak of the COVID outbreak (T1) and Post-Traumatic Stress Disorder (PTSD) symptoms concurrently, and at the remission periods of COVID in China three months (T2) and six months (T3) later in a sample of 6th to 12th-grade students (N = 782). The results showed that forward-focus coping was negatively associated with PTSD symptoms across all three timepoints and predicted reduced risk for more PTSD symptoms at T2, and trauma-focus coping was positively associated with PTSD symptoms across all three timepoints and predicted higher risk of PTSD symptoms both at T2 and T3. There was an interaction effect of trauma-focus coping and T1 symptoms on later symptoms (T3) - trauma-focus coping was more detrimental for those who had more initial symptoms. The results showed the beneficial effects of future-oriented coping and harmful effects of trauma-focus coping for Chinese youth during the epidemic. Clinical implications of the results were discussed.

A Potent Neutralizing Nanobody Targeting the Spike Receptor-Binding Domain of SARS-CoV-2 and the Structural Basis of Its Intimate Binding.

The continuous spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) around the world has raised unprecedented challenges to the human society. Antibodies and nanobodies possessing neutralization activity represent promising drug candidates. In this study, we report the identification and characterization of a potent SARS-CoV-2 neutralizing nanobody that targets the viral spike receptor-binding domain (S-RBD). The nanobody, termed as Nb-007, engages SARS-CoV-2 S-RBD with the two-digit picomolar binding affinity and shows outstanding virus entry-inhibition activity. The complex structure of Nb-007 bound to SARS-CoV-2 S-RBD reveals an epitope that is partially overlapping with the binding site for the human receptor of angiotensin-converting enzyme 2 (ACE2). The nanobody therefore exerts neutralization by competing with ACE2 for S-RBD binding, which is further ascertained by our in-vitro biochemical analyses. Finally, we also show that Nb-007 reserves promising, though compromised, neutralization activity against the currently-circulating Delta variant and that fusion of the nanobody with Fc dramatically increases its entry-inhibition capacity. Taken together, these data have paved the way of developing Nb-007 as a drug-reserve for potential treatment of SARS-CoV-2 related diseases.

An engineered 5-helix bundle derived from SARS-CoV-2 S2 pre-binds sarbecoviral spike at both serological- and endosomal-pH to inhibit virus entry.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and related sarbecoviruses enter host cells by receptor-recognition and membrane-fusion. An indispensable step in fusion is the formation of 6-helix bundle by viral spike heptad repeats 1 and 2 (HR1 and HR2). Here, we report the construction of 5-helix bundle (5HB) proteins for virus infection inhibition. The optimal construct inhibits SARS-CoV-2 pseudovirus entry with sub-micromolar IC50. Unlike HR2-based peptides that cannot bind spike in the pre-fusion conformation, 5HB features with the capability of binding to pre-fusion spike. Furthermore, 5HB binds viral HR2 at both serological- and endosomal-pH, highlighting its entry-inhibition capacity when SARS-CoV-2 enters via either cell membrane fusion or endosomal route. Finally, we show that 5HB could neutralize S-mediated entry of the predominant SARS-CoV-2 variants and a wide spectrum of sarbecoviruses. These data provide proof-of-concept evidence that 5HB might be developed for the prevention and treatment of SARS-CoV-2 and other emerging sarbecovirus infections.

Diabetes patients with comorbidities had unfavorable outcomes following COVID-19: A retrospective study.

BACKGROUND: Previous studies have shown that diabetes mellitus is a common comorbidity of coronavirus disease 2019 (COVID-19), but the effects of diabetes or anti-diabetic medication on the mortality of COVID-19 have not been well described. AIM: To investigate the outcome of different statuses (with or without comorbidity) and anti-diabetic medication use before admission of diabetic after COVID-19. METHODS: In this multicenter and retrospective study, we enrolled 1422 consecutive hospitalized patients from January 21, 2020, to March 25, 2020, at six hospitals in Hubei Province, China. The primary endpoint was in-hospital mortality. Epidemiological material, demographic information, clinical data, laboratory parameters, radiographic characteristics, treatment and outcome were extracted from electronic medical records using a standardized data collection form. Most of the laboratory data except fasting plasma glucose (FPG) were obtained in first hospitalization, and FPG was collected in the next day morning. Major clinical symptoms, vital signs at admission and comorbidities were collected. The treatment data included not only COVID-19 but also diabetes mellitus. The duration from the onset of symptoms to admission, illness severity, intensive care unit (ICU) admission, and length of hospital stay were also recorded. All data were checked by a team of sophisticated physicians. RESULTS: Patients with diabetes were 10 years older than non-diabetic patients [(39 - 64) vs (56 - 70), P < 0.001] and had a higher prevalence of comorbidities such as hypertension (55.5% vs 21.4%, P < 0.001), coronary heart disease (CHD) (9.9% vs 3.5%, P < 0.001), cerebrovascular disease (CVD) (3% vs 2.2%, P < 0.001), and chronic kidney disease (CKD) (4.7% vs 1.5%, P = 0.007). Mortality (13.6% vs 7.2%, P = 0.003) was more prevalent among the diabetes group. Further analysis revealed that patients with diabetes who took acarbose had a lower mortality rate (2.2% vs 26.1, P < 0.01). Multivariable Cox regression showed that male sex [hazard ratio (HR) 2.59 (1.68 - 3.99), P < 0.001], hypertension [HR 1.75 (1.18 - 2.60), P = 0.006), CKD [HR 4.55 (2.52-8.20), P < 0.001], CVD [HR 2.35 (1.27 - 4.33), P = 0.006], and age were risk factors for the COVID-19 mortality. Higher HRs were noted in those aged ≥ 65 (HR 11.8 [4.6 - 30.2], P < 0.001) vs 50-64 years (HR 5.86 [2.27 - 15.12], P < 0.001). The survival curve revealed that, compared with the diabetes only group, the mortality was increased in the diabetes with comorbidities group (P = 0.009) but was not significantly different from the non-comorbidity group (P = 0.59). CONCLUSION: Patients with diabetes had worse outcomes when suffering from COVID-19; however, the outcome was not associated with diabetes itself but with comorbidities. Furthermore, acarbose could reduce the mortality in diabetic.

Glycyrrhizic Acid Inhibits SARS-CoV-2 Infection by Blocking Spike Protein-Mediated Cell Attachment.

Glycyrrhizic acid (GA), also known as glycyrrhizin, is a triterpene glycoside isolated from plants of Glycyrrhiza species (licorice). GA possesses a wide range of pharmacological and antiviral activities against enveloped viruses including severe acute respiratory syndrome (SARS) virus. Since the S protein (S) mediates SARS coronavirus 2 (SARS-CoV-2) cell attachment and cell entry, we assayed the GA effect on SARS-CoV-2 infection using an S protein-pseudotyped lentivirus (Lenti-S). GA treatment dose-dependently blocked Lenti-S infection. We showed that incubation of Lenti-S virus, but not the host cells with GA prior to the infection, reduced Lenti-S infection, indicating that GA targeted the virus for infection. Surface plasmon resonance measurement showed that GA interacted with a recombinant S protein and blocked S protein binding to host cells. Autodocking analysis revealed that the S protein has several GA-binding pockets including one at the interaction interface to the receptor angiotensin-converting enzyme 2 (ACE2) and another at the inner side of the receptor-binding domain (RBD) which might impact the close-to-open conformation change of the S protein required for ACE2 interaction. In addition to identifying GA antiviral activity against SARS-CoV-2, the study linked GA antiviral activity to its effect on virus cell binding.

S19W, T27W, and N330Y mutations in ACE2 enhance SARS-CoV-2 S-RBD binding toward both wild-type and antibody-resistant viruses and its molecular basis.

SARS-CoV-2 recognizes, via its spike receptor-binding domain (S-RBD), human angiotensin-converting enzyme 2 (ACE2) to initiate infection. Ecto-domain protein of ACE2 can therefore function as a decoy. Here we show that mutations of S19W, T27W, and N330Y in ACE2 could individually enhance SARS-CoV-2 S-RBD binding. Y330 could be synergistically combined with either W19 or W27, whereas W19 and W27 are mutually unbeneficial. The structures of SARS-CoV-2 S-RBD bound to the ACE2 mutants reveal that the enhanced binding is mainly contributed by the van der Waals interactions mediated by the aromatic side-chains from W19, W27, and Y330. While Y330 and W19/W27 are distantly located and devoid of any steric interference, W19 and W27 are shown to orient their side-chains toward each other and to cause steric conflicts, explaining their incompatibility. Finally, using pseudotyped SARS-CoV-2 viruses, we demonstrate that these residue substitutions are associated with dramatically improved entry-inhibition efficacy toward both wild-type and antibody-resistant viruses. Taken together, our biochemical and structural data have delineated the basis for the elevated S-RBD binding associated with S19W, T27W, and N330Y mutations in ACE2, paving the way for potential application of these mutants in clinical treatment of COVID-19.

Crystal structure of SARS-CoV-2 nsp10 bound to nsp14-ExoN domain reveals an exoribonuclease with both structural and functional integrity.

The emergence of SARS-CoV-2 infection has posed unprecedented threat to global public health. The virus-encoded non-structural protein 14 (nsp14) is a bi-functional enzyme consisting of an exoribonuclease (ExoN) domain and a methyltransferase (MTase) domain and plays a pivotal role in viral replication. Here, we report the structure of SARS-CoV-2 nsp14-ExoN domain bound to its co-factor nsp10 and show that, compared to the SARS-CoV nsp10/nsp14-full-length complex, SARS-CoV-2 nsp14-ExoN retains an integral exoribonuclease fold and preserves an active configuration in the catalytic center. Analysis of the nsp10/nsp14-ExoN interface reveals a footprint in nsp10 extensively overlapping with that observed in the nsp10/nsp16 structure. A marked difference in the co-factor when engaging nsp14 and nsp16 lies in helix-α1', which is further experimentally ascertained to be involved in nsp14-binding but not in nsp16-engagement. Finally, we also show that nsp10/nsp14-ExoN is enzymatically active despite the absence of nsp14-MTase domain. These data demonstrate that SARS-CoV-2 nsp10/nsp14-ExoN functions as an exoribonuclease with both structural and functional integrity.

Psychometric Evaluation of the Chinese Recovering Quality of Life (ReQoL) Outcome Measure and Assessment of Health-Related Quality of Life During the COVID-19 Pandemic.

OBJECTIVE: The primary objective was to translate the Recovering Quality of Life (ReQoL) measures from English to traditional Chinese and assess their psychometric properties in Hong Kong (HK) Chinese population. The secondary objective was to investigate the mental health-related quality of life (HRQoL) of this sample during the coronavirus disease 2019 (COVID-19) pandemic. METHOD: Recovering Quality of Life was translated to Traditional Chinese adhering to standard guideline recommended by the official distributors. Five hundred members of the general population were successfully recruited to participate in a telephone-based survey. The following psychometric properties of the ReQoL were evaluated: construct, convergent, and known-group validity and internal consistency and test-retest reliability. The item measurement invariance was assessed on the basis of differential item functioning (DIF). Multiple regression analysis was used to assess the relationship between respondents' characteristics and mental HRQoL. RESULTS: Results of confirmatory factor analysis (CFA) supported a two-factor structure of the ReQoL. The ReQoL showed significant correlations with the other mental health, quality of life, and well-being measures, which indicated a satisfactory convergent validity. Known-group validity confirmed that ReQoL is able to differentiate between people with different mental health status. The (Cronbach's alpha = 0.91 and 0.76 for positive [PF] and negative [NF] factor), and McDonald's omega of 0.89 (PF = 0.94, NF = 0.82) indicated the ReQoL has good reliability as well as test-retest reliability with an intraclass correlation coefficient of 0.75. Four items showed negligible DIF with respect to age. Respondents who were highly educated and without psychological problems reported a high ReQoL score. CONCLUSION: Traditional Chinese ReQoL was shown to be a valid and reliable instrument to assess the recovery-focused quality of life in HK general population. Future studies are needed to appraise its psychometric properties in local people experiencing mental disorders.

Chronic Cardio-Metabolic Disease Increases the Risk of Worse Outcomes Among Hospitalized Patients With COVID-19: A Multicenter, Retrospective, and Real-World Study.

Background Although chronic cardio-metabolic disease is a common comorbidity among patients with COVID-19, its effects on the clinical characteristics and outcome are not well known. Methods and Results This study aimed to explore the association between underlying cardio-metabolic disease and mortality with COVID-19 among hospitalized patients. This multicenter, retrospective, and real-world study was conducted from January 22, 2020 to March 25, 2020 in China. Data between patients with and without 5 main cardio-metabolic diseases including hypertension, diabetes mellitus, coronary heart disease, cerebrovascular disease, and hyperlipidemia were compared. A total of 1303 hospitalized patients were included in the final analysis. Of them, 520 patients (39.9%) had cardio-metabolic disease. Compared with patients without cardio-metabolic disease, more patients with cardio-metabolic disease had COVID-related complications including acute respiratory distress syndrome (9.81% versus 3.32%; P<0.001), acute kidney injury (4.23% versus 1.40%; P=0.001), secondary infection (13.9% versus 9.8%; P=0.026), hypoproteinemia (12.1% versus 5.75%; P<0.001), and coagulopathy (19.4% versus 10.3%; P<0.001), had higher incidences of the severe type of COVID-19 (32.9% versus 16.7%; P<0.001), more were admitted to the intensive care unit (11.7% versus 7.92%; P=0.021), and required mechanical ventilation (9.8% versus 4.3%; P<0.001). When the number of the patients' cardio-metabolic diseases was 0, 1, and >2, the mortality was 4.2%, 11.1%, and 19.8%, respectively. The multivariable-adjusted hazard ratio of mortality among patients with cardio-metabolic disease was 1.80 (95% CI, 1.17-2.77). Conclusions Cardio-metabolic disease was a common condition among hospitalized patients with COVID-19, and it was associated with higher risks of in-hospital mortality.

Elevated Lactate Dehydrogenase (LDH) level as an independent risk factor for the severity and mortality of COVID-19.

Early identification of severe patients with coronavirus disease 2019 (COVID-19) is very important for individual treatment. We included 203 patients with COVID-19 by propensity score matching in this retrospective, case-control study. The effects of serum lactate dehydrogenase (LDH) at admission on patients with COVID-19 were evaluated. We found that serum LDH levels had a 58.7% sensitivity and 82.0% specificity, based on a best cut-off of 277.00 U/L, for predicting severe COVID-19. And a cut-off of 359.50 U/L of the serum LDH levels resulted in a 93.8% sensitivity, 88.2% specificity for predicting death of COVID-19. Additionally, logistic regression analysis and Cox proportional hazards model respectively indicated that elevated LDH level was an independent risk factor for the severity (HR: 2.73, 95% CI: 1.25-5.97; P=0.012) and mortality (HR: 40.50, 95% CI: 3.65-449.28; P=0.003) of COVID-19. Therefore, elevated LDH level at admission is an independent risk factor for the severity and mortality of COVID-19. LDH can assist in the early evaluating of COVID-19. Clinicians should pay attention to the serum LDH level at admission for patients with COVID-19.

Statistical and network analysis of 1212 COVID-19 patients in Henan, China.

BACKGROUND: COVID-19 is spreading quickly all over the world. Publicly released data for 1212 COVID-19 patients in Henan of China were analyzed in this paper. METHODS: Various statistical and network analysis methods were employed. RESULTS: We found that COVID-19 patients show gender (55% vs 45%) and age (81% aged between 21 and 60) preferences; possible causes were explored. The estimated average, mode and median incubation periods are 7.4, 4 and 7 days. Incubation periods of 92% of patients were no more than 14 days. The epidemic in Henan has undergone three stages and has shown high correlations with the numbers of patients recently returned from Wuhan. Network analysis revealed that 208 cases were clustering infected, and various People's Hospitals are the main force in treating COVID-19. CONCLUSIONS: The incubation period was statistically estimated, and the proposed state transition diagram can explore the epidemic stages of emerging infectious disease. We suggest that although the quarantine measures are gradually working, strong measures still might be needed for a period of time, since ∼7.45% of patients may have very long incubation periods. Migrant workers or college students are at high risk. State transition diagrams can help us to recognize the time-phased nature of the epidemic. Our investigations have implications for the prevention and control of COVID-19 in other regions of the world.