Protectin Conjugates in Tissue Regeneration 1 Inhibits Macrophage Pyroptosis by Restricting NLRP3 Inflammasome Assembly to Mitigate Sepsis via the cAMP-PKA Pathway.

Protectin conjugates in tissue regeneration 1 (PCTR1) is a novel anti-inflammatory and proresolving lipid mediator biosynthesized from docosahexaenoic acid. Excessive activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome and consequent pyroptosis are involved in diverse inflammatory diseases. However, how PCTR1 affects NLRP3 inflammasome activation and pyroptosis are still unclear. Here, we demonstrated that PCTR1 inhibited NLRP3 inflammasome activation and pyroptosis. These results show that PCTR1 dose-dependently inhibited gasdermin D cleavage in lipopolysaccharide (LPS)-primed murine primary macrophages upon nigericin stimulation. Additionally, PCTR1 treatment after LPS priming inhibited caspase-1 activation and subsequent mature interleukin-1ß release independent of the nuclear factor-kappa B pathway. PCTR1 exerted its inhibitory effects by blocking NLRP3-apoptosis-associated speck-like protein containing a CARD (ASC) interaction and ASC oligomerization, thereby restricting NLRP3 inflammasome assembly. However, the inhibitory effect of PCTR1 could be reversed by KH7 and H89, which are the inhibitors of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling pathway. Moreover, PCTR1 treatment alleviated lung tissue damage and improved mouse survival in LPS-induced sepsis. Our study unveils the molecular mechanism of negative regulation of NLRP3 inflammasome activation and pyroptosis by a novel lipid mediator and suggests that PCTR1 may serve as a potential treatment option for NLRP3-inflammasome driven diseases.

CAPRL Scoring System for Prediction of 30-day Mortality in 949 Patients with Coronavirus Disease 2019 in Wuhan, China: A Retrospective, Observational Study.

Background: Coronavirus disease 2019 (COVID-19) is a serious and even lethal respiratory illness. The mortality of critically ill patients with COVID-19, especially short term mortality, is considerable. It is crucial and urgent to develop risk models that can predict the mortality risks of patients with COVID-19 at an early stage, which is helpful to guide clinicians in making appropriate decisions and optimizing the allocation of hospital resoureces. Methods: In this retrospective observational study, we enrolled 949 adult patients with laboratory-confirmed COVID-19 admitted to Tongji Hospital in Wuhan between January 28 and February 12, 2020. Demographic, clinical and laboratory data were collected and analyzed. A multivariable Cox proportional hazard regression analysis was performed to calculate hazard ratios and 95% confidence interval for assessing the risk factors for 30-day mortality. Results: The 30-day mortality was 11.8% (112 of 949 patients). Forty-nine point nine percent (474) patients had one or more comorbidities, with hypertension being the most common (359 [37.8%] patients), followed by diabetes (169 [17.8%] patients) and coronary heart disease (89 [9.4%] patients). Age above 50 years, respiratory rate above 30 beats per minute, white blood cell count of more than10 × 109/L, neutrophil count of more than 7 × 109/L, lymphocyte count of less than 0.8 × 109/L, platelet count of less than 100 × 109/L, lactate dehydrogenase of more than 400 U/L and high-sensitivity C-reactive protein of more than 50 mg/L were independent risk factors associated with 30-day mortality in patients with COVID-19. A predictive CAPRL score was proposed integrating independent risk factors. The 30-day mortality were 0% (0 of 156), 1.8% (8 of 434), 12.9% (26 of 201), 43.0% (55 of 128), and 76.7% (23 of 30) for patients with 0, 1, 2, 3, ≥4 points, respectively. Conclusions: We designed an easy-to-use clinically predictive tool for assessing 30-day mortality risk of COVID-19. It can accurately stratify hospitalized patients with COVID-19 into relevant risk categories and could provide guidance to make further clinical decisions.

Inhibitory effect of dexamethasone on expression of cysteine-rich 61 protein in airway epithelial cells of allergic mouse models.

In order to study whether cysteine-rich 61 protein (cyr61) is involved in the pathogenesis of asthma and its relation to airway inflammation, the effect of dexamethasone (Dxm) on the expression of cyr61 in the lung tissues of asthmatic mice was investigated. Forty BALB/c mice were divided into asthma group (n=15), control group (n=10) and Dxm group (n=15). The asthma group was sensitized and challenged by ovalbumin (OVA). The mice in Dxm group were intraperitoneally administered with Dxm after OVA challenge. The expression of cyr61 in the lung tissues was detected by using immunohistochemistry, and that of eotaxin protein in the bronchoalveolar lavage fluid (BALF) by using enzyme-linked immunosorbent assay (ELISA). The number of inflammatory cells in BALF was also analyzed. The results showed that the cyr61 expression was highest in asthma group (P<0.05), followed by Dxm group (P<0.05) and control group. The cyr61 had a positive correlation with the total nucleated cells (r=0.867, P<0.05), especially eosinophils (r=0.856, P<0.05), and eotaxin level (r=0.983, P<0.05) in the BALF. Our findings suggested that cyr61 is expressed in airway epithelial cells and has a positive correlation with eotaxin and number of airway infiltrating eosinophils.

Effect of dexamethasone on expression of AGR2 protein in asthmatic mice.

This study examined the expression of the anterior gradient-2 (AGR2) protein and Muc5ac protein in the lung tissues of asthmatic mice and the effect of dexamethasone, with an attempt to explore the role of AGR2 in the over-secretion of mucus in the airway. Eighteen BALB/c mice were divided into asthma group, control group and dexamethasone group. In dexamethasone group, dexamethasone was intraperitoneally administered. Expression of AGR2 protein and Muc5ac protein in the murine lung tissues was immunohistochemically detected. IL-13 level was determined in the bronchoalveolar lavage fluid (BALF) by ELISA. The results exhibited that the expression of AGR2 protein in asthma group (0.522±0.041) was significantly higher than that in normal controls (0.361±0.047) (P<0.01) and bore a positive linear relationship to the expression of Muc5ac protein (r=0.873, P<0.05) and IL-13 level (r=0.828, P<0.05). Expression of AGR2 protein in the dexamethasone group (0.456±0.049) was significantly lower than that in the asthma group. It was concluded that: (1) the expression of AGR2 protein was significantly higher in asthmatic mice as compared with their normal counterparts; (2) the expression was obviously related to the expression of Muc5ac protein and IL-13; (3) dexamethasone could down-regulate the expression of AGR2 protein. Our findings suggested that AGR2 might be involved in the over-secretion of mucus in the airway in asthma.

Diagnostic value of interleukin 21 and carcinoembryonic antigen levels in malignant pleural effusions.

The aim of this study was to evaluate the diagnostic value of interleukin 21 (IL-21) and carcinoembryonic antigen (CEA) in tuberculous pleural effusions (TPEs) and malignant pleural effusions (MPEs). Pleural effusion samples from 103 patients were classified on the basis of diagnosis as TPE (n=51) and MPE (n=52). The concentration of IL-21 was determined by ELISA. Lactate dehydrogenase (LDH), adenosine dehydrogenase (ADA) and CEA levels were also determined in all patients. A significant difference was observed in the levels of ADA and CEA (P<0.01), but not in the levels of LDH (P>0.05) between TPE and MPE. The concentration of IL-21 in MPE was significantly higher compared to TPE (P<0.01). With a threshold value of 4.32 pg/ml, IL-21 had a sensitivity of 76.9% (40/52) and a specificity of 80.4% (41/51). Combined detection of IL-21 and CEA had a sensitivity of 69.2% (36/52) and a specificity of 92.2% (47/51). These two markers can contribute to the differential diagnosis of MPEs.