Porcine epidemic diarrhea virus 3CLpro causes apoptosis and collapse of mitochondrial membrane potential requiring its protease activity and signaling through MAVS.

Porcine epidemic diarrhea (PED) is a highly contagious and virulent intestinal infectious disease characterized by diarrhea, vomiting and dehydration. Although PEDV-induced apoptosis has been characterized in vitro and vivo, the functional proteins related to this event and the mechanism still need further research. Here, we firstly demonstrated that PEDV epidemic strain JS2013 could trigger apoptosis in a dose- and time-dependent manner. Then, PEDV 3CLpro was further identified as a crucial inducer of PEDV-triggered apoptosis. In addition, using site-directed mutagenesis to disrupt the protease activity of 3CLpro by His41 and Cys144 mutations, we found that 3CLpro-induced apoptosis and mitochondrial damage significantly reduced, suggesting that the protease activity of 3CLpro was essential for apoptosis and mitochondrial damage. Furthermore, PEDV 3CLpro could synergistically promote MAVS-mediated apoptosis and MAVS was involved in the signaling pathway of 3CLpro-induced apoptosis, but no direct interaction between PEDV 3CLpro and MAVS was detected by immunoprecipitation assays. Our findings provide important insights into the role of 3CLpro in the pathogenicity of PEDV.

FABP4-mediated lipid droplet formation in Streptococcus uberis-infected macrophages supports host defence.

Foamy macrophages containing prominent cytoplasmic lipid droplets (LDs) are found in a variety of infectious diseases. However, their role in Streptococcus uberis-induced mastitis is unknown. Herein, we report that S. uberis infection enhances the fatty acid synthesis pathway in macrophages, resulting in a sharp increase in LD levels, accompanied by a significantly enhanced inflammatory response. This process is mediated by the involvement of fatty acid binding protein 4 (FABP4), a subtype of the fatty acid-binding protein family that plays critical roles in metabolism and inflammation. In addition, FABP4 siRNA inhibitor cell models showed that the deposition of LDs decreased, and the mRNA expression of Tnf, Il1b and Il6 was significantly downregulated after gene silencing. As a result, the bacterial load in macrophages increased. Taken together, these data demonstrate that macrophage LD formation is a host-driven component of the immune response to S. uberis. FABP4 contributes to promoting inflammation via LDs, which should be considered a new target for drug development to treat infections.

A Comparative Study on the Psychological Health of Frontline Health Workers in Wuhan Under and After the Lockdown.

Background: The coronavirus disease-2019 (COVID-19) outbreak and a 3-month lockdown of Wuhan may have had a long-term impact on the mental health of frontline healthcare workers (HWs). However, there is still a lack of comparative studies on the mental health of front-line HWs in the initial phase of the lockdown and 1 month after the lifting of the lockdown. Methods: We recruited 1717 HWs during the initial phase of the lockdown and 2214 HWs 1 month after the lifting of the lockdown, and their baseline characteristics and psychiatric health in these two phases were compared. Furthermore, Pearson's Chi-square test and multivariate logistic regression analysis were used to determine the possible risk factors associated with depressive symptoms in the front-line HWs. Results: Compared with the initial phase of the lockdown, the proportion of HWs with anxiety symptoms and stress decreased, while the proportion of HWs with depressive symptoms increased a month after the lifting of the lockdown. Male sex, exercise habit, comorbidities, and having family members or relatives with suspected or confirmed COVID-19 infection were significantly related to the increased incidence of depressive symptoms during the initial phase of the lockdown. Comorbidities, negative effect of media coverage, working >4 days a week, lower annual household income, and deteriorating relationships with family members were associated with depressive symptoms a month after the lifting of the lockdown. Conclusion: The increased proportion of HWs with depressive symptoms 1 month after the lifting of the lockdown suggested that mental health of front-line HWs should be a top-priority issue, not only during, but also after the pandemic.

Chitosan functionalized graphene oxide nanocomposites for fluorescence imaging of apoptotic processes and targeted anti-inflammation study.

This work reports novel chitosan functionalized graphene oxide (GO) nanocomposites combined fluorescence imaging and therapeutic functions in one agent, which can serve as a promising alternative to alleviate related diseases caused hyperinflammation. Briefly, GO was designed to be conjugated with chitosan, fluorescein-labeled peptide, toll-like receptor 4 antibody and hydroxycamptothecin/aloe emodin. We have demonstrated that such nanocomposites could effectively achieve active targeted delivery of pro-apoptotic and anti-inflammatory drugs into inflammatory cells and cause cells apoptosis by acid-responsive drug release. Moreover, confocal fluorescence imaging confirms that the drug-induced inflammatory cells apoptosis could be visualized the light-up fluorescence of fluorescein activated by caspase-3. Meanwhile, inflammatory-related biomarkers have down-regulated after the nanocomposites' treatment in both vitro and vivo experiments consistent with the results in histological sections. In summary, the bifunctional nanocomposites that possess anti-inflammation and fluorescence imaging could serve as a promising therapeutic agent for reducing hyperinflammation caused by numerous diseases.

A label-free electrochemical assay for coronavirus IBV H120 strain quantification based on equivalent substitution effect and AuNPs-assisted signal amplification.

A label-free electrochemical strategy is proposed combining equivalent substitution effect with AuNPs-assisted signal amplification. According to the differences of S1 protein in various infectious bronchitis virus (IBV) strains, a target DNA sequence that can specifically recognize H120 RNA forming a DNA-RNA hybridized double-strand structure has been designed. Then, the residual single-stranded target DNA is hydrolyzed by S1 nuclease. Therefore, the content of target DNA becomes equal to the content of virus RNA. After equivalent coronavirus, the target DNA is separated from DNA-RNA hybridized double strand by heating, which can partly hybridize with probe 2 modified on the electrode surface and probe 1 on AuNPs' surface. Thus, AuNPs are pulled to the surface of the electrode and the abundant DNA on AuNPs' surface could adsorb a large amount of hexaammineruthenium (III) chloride (RuHex) molecules, which produce a remarkably amplified electrochemical response. The voltammetric signal of RuHex with a peak near - 0.28 V vs. Ag/AgCl is used as the signal output. The proposed method shows a detection range of 1.56e-9 to 1.56e-6 µM with the detection limit of 2.96e-10 µM for IBV H120 strain selective quantification detection, exhibiting good accuracy, stability, and simplicity, which shows a great potential for IBV detection in vaccine research and avian infectious bronchitis diagnosis. Graphical abstract.

COVID-19 in Wuhan: Sociodemographic characteristics and hospital support measures associated with the immediate psychological impact on healthcare workers.

BACKGROUND: The outbreak of COVID-19 has laid unprecedented threats and challenges to health workers (HWs) in Wuhan, China. We aimed to assess the sociodemographic characteristics and hospital support measures associated with the immediate psychological impact on HWs at Tongji Hospital in Wuhan during COVID-19 outbreak. METHODS: We conducted a single-center, cross-sectional survey of HWs via online questionnaires between February 8th and 10th, 2020. We evaluated stress, depression and anxiety by IES-R, PHQ-9, and GAD-7, respectively. We also designed a questionnaire to assess the perceptions of threat of COVID-19, and the satisfactions of the hospital's support measures. Multivariate logistic regressions were used to identify associated variables of acute stress, depression, and anxiety. FINDINGS: We received 5062 completed questionnaires (response rate, 77.1%). 29.8%, 13.5% and 24.1% HWs reported stress, depression and anxiety symptoms. Women (odds ratio [OR], 1.31; 95% CI, 0.47-0.97; p = 0.032), years of working >10 years (OR, 2.02; 95% CI, 1.47-2.79; p<0.001), concomitant chronic diseases (OR, 1.51; 95% CI, 1.27-1.80; p<0.001), history of mental disorders (OR, 3.27; 95% CI, 1.77-6.05; p<0.001), family members or relatives confirmed or suspected (OR, 1.23; 95% CI, 1.02-1.48; p = 0.03), hospital-based and department-based care (OR, 0.76; 95% CI, 0.60-0.97; p = 0.024) and full coverage of all departments for avoiding nosocomial infection (OR, 0.69; 95% CI, 0.53-0.89; p = 0.004) were associated with stress. INTERPRETATION: Women and those who have more than 10 years of working, concomitant chronic diseases, history of mental disorders, and family members or relatives confirmed or suspected are susceptible to stress, depression and anxiety among HWs during the pandemic. In addition, since HWs often have a greater stigma against mental problems than the general public, it is worthwhile to address the needs of the HWs during this pandemic and to provide appropriate psychological supports for those people at high risk of mental problems.