Prediction of superantigen active sites and clonal expression of staphylococcal enterotoxin-like W / 中华流行病学杂志

Objective: The docking and superantigen activity sites of staphylococcal enterotoxin-like W (SElW) and T cell receptor (TCR) were predicted, and its SElW was cloned, expressed and purified. Methods: AlphaFold was used to predict the 3D structure of SElW protein monomers, and the protein models were evaluated with the help of the SAVES online server from ERRAT, Ramachandran plot, and Verify_3D. The ZDOCK server simulates the docking conformation of SElW and TCR, and the amino acid sequences of SElW and other serotype enterotoxins were aligned. The primers were designed to amplify selw, and the fragment was recombined into the pMD18-T vector and sequenced. Then recombinant plasmid pMD18-T was digested with BamHⅠand Hind Ⅲ. The target fragment was recombined into the expression plasmid pET-28a(+). After identification of the recombinant plasmid, the protein expression was induced by isopropyl-beta-D- thiogalactopyranoside. The SElW expressed in the supernatant was purified by affinity chromatography and quantified by the BCA method. Results: The predicted three-dimensional structure showed that the SElW protein was composed of two domains, the amino-terminal and the carboxy-terminal. The amino-terminal domain was composed of 3 α-helices and 6 β-sheets, and the carboxy-terminal domain included 2 α-helices and 7 antiparallel β-sheets composition. The overall quality factor score of the SElW protein model was 98.08, with 93.24% of the amino acids having a Verify_3D score ≥0.2 and no amino acids located in disallowed regions. The docking conformation with the highest score (1 521.328) was selected as the analysis object, and the 19 hydrogen bonds between the corresponding amino acid residues of SElW and TCR were analyzed by PyMOL. Combined with sequence alignment and the published data, this study predicted and found five important superantigen active sites, namely Y18, N19, W55, C88, and C98. The highly purified soluble recombinant protein SElW was obtained with cloning, expression, and protein purification. Conclusions: The study found five superantigen active sites in SElW protein that need special attention and successfully constructed and expressed the SElW protein, which laid the foundation for further exploration of the immune recognition mechanism of SElW.

Effect of the JAK2/STAT3 signaling pathway on epithelial mesenchymal transition of the peritoneum in uremic peritoneal dialysis rats / 中华肾脏病杂志

Objective To investigate whether the JAK2/STAT3 signaling pathway is involved in the epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells in uremic peritoneal dialysis (PD) rats.Methods A total of 48 male Sprague-Dawley (SD) rats were randomly separated into six groups:normal control group (NC group,n=8),sham group (n=8),uremic group (n=8),PD group (n=8),S3I-201 control group (n=8) and S3I-201 group (n=8).Uremic model generated by 5/6 nephrectomy surgery in rats was established.The rats of PD group,S3I-201 control group and S3I-201 group received daily infusion of 4.25％ glucose-based peritoneal dialysate fluid (3 ml/100 g) from PD catheters for 28 days.Rats of S3I-201 group were injected with STAT3 inhibitor S3I-201 (2.5 mg/kg) solution from the catheters every other day;the same dose of the solvent of S3I-201 was simultaneously given to S3I-201 control group rats.After PD for 28 days,peritoneal function,pathologic changes,and microvessel density (MVD) were evaluated.Creatinine,urea nitrogen and interleukin-6 (IL-6) concentration in blood and dialysate,and protein and mRNA levels of phospho-JAK2 (p-JAK2),phospho-STAT3 (p-STAT3),E-cadherin,alpha-smooth muscle actin (α-SMA) and vascular endothelial growth factor (VEGF) in peritoneum were determined.Results Uremia and peritoneal dialysate could aggravate the peritoneal function and elevate peritoneal thickness and MVD.They could also increased the concentration of IL-6 in blood and dialysate and the expression levels of α-SMA,VEGF,p-JAK2 and p-STAT3 in peritoneum,while lowering E-cadherin expression in peritoneum.These manifestations were even more remarkable in PD group compared to those in uremic group.There was no statistical difference between the S3I-201 control group and the PD group as regards all the index (all P ＞ 0.05).Compared with the S3I-201 control group,the rats treated with S3I-201 showed better peritoneal function.S3I-201 could reduce peritoneal thickness (P＜0.05),MVD (P＜0.05),the concentration of IL-6 in blood and dialysate,the mRNA and protein expression of α-SMA,VEGF,p-JAK2 and p-STAT3 (all P ＜ 0.05),while enhance the mRNA and protein expression of E-cadherin (all P ＜ 0.05).Conclusions After STAT3 is inhibited,the peritoneal thickness,MVD and IL-6 concentration in PD rats are decreased,and EMT is also inhibited,while peritoneal function is improved.The JAK2/STAT3 signaling pathway may thus be involved in the process of EMT of peritoneum in uremic peritoneal dialysis rats by regulating the expression of IL-6.

Association between red cell distribution width and mortality in patients undergoing continuous ambulatory peritoneal dialysis / 中华肾脏病杂志

Objective To investigate the association of red cell distribution width (RDW) with all-cause and cardiovascular disease (CVD)-related mortality in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).Methods A retrospective analysis was performed on 207 patients who initiated CAPD for more than 3 months between July 2005 and March 2016 in the First Hospital Affiliated to Zhengzhou University.Baseline data on demographic,clinical and biochemical variables as well as comorbidities were obtained;medications and clinic outcomes were recorded.According to receiver operator characteristic curve (ROC) analysis,patients were divided into high RDW (RDW ＞ 15.1％) and low RDW (RDW≤ 15.1％) groups.The data of two groups were compared and Spearman's correlation analysis was used to explore the association of RDW with clinical and biochemical parameters.Survival curves were calculated using Kaplan-Meier method.Cox regression model was employed to analyze risk factors of all-cause and CVD-related mortality.Results In this study,207 CAPD patients were enrolled.The overall median survival time was 80 months.And the median survival time of high RDW group (68 patients) and low RDW group (139 patients) were 59 months and 96 months,respectively.There were statistical differences in diastole pressure,hemoglobin,hematocrit,serum albumin,intact parathyroid hormone (iPTH),eGFR,cholesterol,lipoprotein a,4-hour dialysate-to-plasma ratio for creatinine (4hD/Pcr),total Ccr (P ＜ 0.05,respectively);the two groups also varied in the proportion of chronic obstructive pulmonary disease,cardiovascular disease and hyperlipidemia,as well as in the use of iron supplements,angiotensin-converting enzyme (ACE) inhibitors or angiotensin Ⅱ receptor blockers (ARB),and beta-receptor blockers (P＜0.05,respectively).Cardiovascular event was a leading cause of mortality.Kaplan-Meier survival curves showed that the high RDW group had higher all-cause and CVD-related mortality compared with the low RDW group (P ＜ 0.01).The 1-year,3-year,and 5-year patient survivals of the high RDW and low RDW group were 87.97％ vs 97.01％,58.02％ vs 81.53％,and 41.62％ vs 67.96％,respectively,demonstrating significant differences (P=0.001).Multivariate Cox regression analysis showed that high RDW was independent risk factor for all-cause mortality (HR=1.212,95％CI:1.007-1.458,P=0.042) and CVD-related mortality (HR=1.697,95％ CI:1.030-2.795,P=0.038).Conclusion RDW is associated with mortality risks in CAPD patients and can be stratified as a valuable indicator for the risk of death.

Interleukin-6 induces epithelial mesenchymal transition of human peritoneal mesothelial cells by STAT3 / 中华肾脏病杂志

Objective To investigate the role of STAT3 transcription factor in IL-6 inducing epithelial mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMCs).Methods HPMCs were cultured in vitro and grouped.(1) According to the stimulation time with 50 μg/L IL-6,HPMCs were divided into 24,48,72 h groups.(2) HPMCs were grouped 50,100 μg/L according to IL-6 concentration.(3) HPMCs were respectively divided into control group,IL-6 group,empty vector group,empty vector+IL-6 group,virus infecting group and virus infecting+IL-6 group,as lenti-virus vector mediating RNA interference targeting STAT3 was applied.The mRNA expressions of E-cadherin,α-smooth muscle actin (α-SMA) and vascular endothelial growth factor (VEGF) were detected by real time PCR;their protein expressions and the phosphorylation of JAK2 and STAT3 were detected by Western blotting;the expressions and distribution of E-cadherin and α-SMA were observed by immunofluorescence.Results Compared with those in control group,the expression of E-cadherin decreased remarkably (P ＜ 0.05),while the expressions of VEGF and α-SMA and the ratio of phosphorylated (p)-JAK2/JAK2 and p-STAT3/STAT3 increased significantly in IL-6 concentration groups and stimulation time groups (all P ＜ 0.05),which had been dose and time dependent.Compared with empty vector+IL-6 group,virus infecting+IL-6 group had decreased expressions of VEGF and α-SMA,while increased expressions of E-cadherin (all P ＜ 0.05).Conclusions IL-6 can promote VEGF and α-SMA gene expression and prevent E-cadherin gene expression by STAT3,which involves in EMT of peritoneum fibrosis.While STAT3 gene is knocked-down,EMT is inhibited in HPMCs.

Interleukin-6 induces epithelial mesenchymal transition of human peritoneal mesothelial cells by STAT3 / 中华肾脏病杂志

Objective To investigate the role of STAT3 transcription factor in IL-6 inducing epithelial mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMCs).Methods HPMCs were cultured in vitro and grouped.(1) According to the stimulation time with 50 μg/L IL-6,HPMCs were divided into 24,48,72 h groups.(2) HPMCs were grouped 50,100 μg/L according to IL-6 concentration.(3) HPMCs were respectively divided into control group,IL-6 group,empty vector group,empty vector+IL-6 group,virus infecting group and virus infecting+IL-6 group,as lenti-virus vector mediating RNA interference targeting STAT3 was applied.The mRNA expressions of E-cadherin,α-smooth muscle actin (α-SMA) and vascular endothelial growth factor (VEGF) were detected by real time PCR;their protein expressions and the phosphorylation of JAK2 and STAT3 were detected by Western blotting;the expressions and distribution of E-cadherin and α-SMA were observed by immunofluorescence.Results Compared with those in control group,the expression of E-cadherin decreased remarkably (P ＜ 0.05),while the expressions of VEGF and α-SMA and the ratio of phosphorylated (p)-JAK2/JAK2 and p-STAT3/STAT3 increased significantly in IL-6 concentration groups and stimulation time groups (all P ＜ 0.05),which had been dose and time dependent.Compared with empty vector+IL-6 group,virus infecting+IL-6 group had decreased expressions of VEGF and α-SMA,while increased expressions of E-cadherin (all P ＜ 0.05).Conclusions IL-6 can promote VEGF and α-SMA gene expression and prevent E-cadherin gene expression by STAT3,which involves in EMT of peritoneum fibrosis.While STAT3 gene is knocked-down,EMT is inhibited in HPMCs.

Rapid and high-throughput identification of recombinant bacteria with mass spectrometry assay / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To construct a rapid and high-throughput assay for identifying recombinant bacteria based on mass spectrometry.</p><p><b>METHODS</b>Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques were used to identify 12 recombinant proteins (10 of Yersinia pestis, 1 of Campylobacter jejuni and 1 of Helicobacter pylori). A classification model for the various phase of recombinant bacteria was established, optimized and validated, using MALDI-TOF MS-ClinProTools system. The differences in the peptide mass spectra were analyzed by using Biotyper and FlexAnalysis softwares.</p><p><b>RESULTS</b>Models of GA, SNN, and QC were established. After optimizing the parameters, the GA recognition model showed good classification capabilities: RC=100%, mean CVA=98.7% (the CVA was 96.4% in phase 1, 100% in phase 2, 98.4% in phase 3, and 100% in phase 4, respectively) and PPV=95%. This model can be used to classify the bacteria and their recombinant, which only requires 3.7×103 cells for analysis. The total time needed is only 10 min from protein extraction to reporting the result for one sample. Furthermore, this assay can automatically detect and test 96 samples concurrently. A total of 48 specific peaks (9, 16, 9, and 14 for the four stages, respectively) was found in the various phase of recombinant bacteria.</p><p><b>CONCLUSION</b>MALDI-TOF MS can be used as a fast, accurate, and high-throughput method to identify recombinant bacteria, which provide a new ideas not only for recombinant bacteria but also for the identification of mutant strains and bioterrorism pathogens.</p>