Protective effect of bone marrow mesenchymal stem cells derived exosomes on alcohol-induced hepatic injury / 中华传染病杂志

Objective To evaluate therapeutic effects of bone marrow mesenchymal stem cells(MSC)derived exosomes on alcohol-induced liver injury.Methods Eighteen male C57BL/6 mice aged 6 to 8 week were randomly divided into control group,model group and exosomes group,with 6 mice in each group.The mice in the model group and the exosomes group were fed with Lieber-DeCarli ad libitum diet(Dyets Inc.)for 4 weeks,followed by gavage a bolus of ethanol at day 26,27 and 28.The mice in the control group matched the alcohol-derived calories with dextran-maltose.Meanwhile,the mice in exosomes group were injected with MSC-exosomes via the tail vein at day 14 and 26.After the experiment,serum levels of alanine aminotransferase(ALT)and aspartate aminotransaminase(AST)were detected,and the pathological changes of liver tissues were observed.The expressions of nuclear factor erythroid 2-related factor 2(Nrf-2),heme oxygenase-1(HO-1),CD63,CD81,TSG101 and Cytochrome C were analyzed by Western blot,and mRNA levels of Nrf-2,HO-1,interleukin(IL)-10 and IL-17 were analyzed by real-time polymerase chain reaction(RT-PCR).The commercial kits were used to detect serum IL-10,IL-17 levels and liver tissue malondialdehyde(MDA),glutathione(GSH),superoxide dismutase(SOD)oxidative stress indicators.The numbers of regulatory T cell(Treg)and help T(Th)17 cells in the liver were analyzed by flow cytometry.One-way analysis of variance was used for comparison between groups.Results MSC-exosomes expressed positive markers CD63,CD81 and TSG101,but did not express the negative markers Cytochrome C.The serum ALT and AST levels in model group were(87.3±25.1)U/L and(223.2±43.5)U/L,respectively,while those in exosomes group were(47.7±12.0)U/L and(128.2±33.6)U/L,respectively.The differences between the two groups were both statistically significant(F=12.818 and 12.226,respectively,both P<0.05).Compared with control group,the SOD activity and GSH level in the model group significantly decreased with statistically significant differences(F=4.245 and 24.074,respectively,both P <0.05).Lieber-DeCarli ethanol feeding significantly increased intrahepatic MDA level in the model mice,which was reversed by MSC-exosomes supplementation,and the difference was statistically significant(F=36.675,P <0.05).Compared with control group,the intrahepatic protein expressions of Nrf-2 and HO-1 in model group were significantly decreased,while the expressions in exosomes group were obviously increased.The differences were statistically significant(F=33.623 and 14.960,respectively,both P <0.05).The expression trends of Nrf-2 and HO-1 mRNA were the same as those of protein expressions(F=20.784 and 276.336,respectively,both P <0.05).The proportions of liver Treg/Th17 in the control group,model group and exosomes group were 4.3±0.9,0.4±0.2,and 3.4±0.5,respectively.The differences among groups were statistically significant(F=64.227,P <0.05).Compared with control group,the serum protein and intrahepatic gene expression of IL-17 in the model group were significantly increased,which were reversed by MSC-exosomes treatment.The differences were statistically significant(F=15.581 and 40.095,respectively,both P<0.05).Serum IL-10 protein levels and intrahepatic IL-10 gene expression were significantly decreased after Lieber-DeCarli ethanol feeding,which were lower than the exosomes group.The differences were statistically significant(F=98.268 and 153.743,respectively,both P <0.05).Conclusions MSC-exosomes transplantation may relieve alcohol-induced liver injury.The mechanism could involve reduction of oxidative stress in the liver via regulating Nrf-2/HO-1 and normalizing the balance of Treg and Th17 cells.

Structural insight into enhanced calcium indicator GCaMP3 and GCaMPJ to promote further improvement

Genetically encoded Ca(2+) indicators (GECI) are important for the measurement of Ca(2+) in vivo. GCaMP2, a widely-used GECI, has recently been iteratively improved. Among the improved variants, GCaMP3 exhibits significantly better fluorescent intensity. In this study, we developed a new GECI called GCaMPJ and determined the crystal structures of GCaMP3 and GCaMPJ. GCaMPJ has a 1.5-fold increase in fluorescence and 1.3-fold increase in calcium affinity over GCaMP3. Upon Ca(2+) binding, GCaMP3 exhibits both monomeric and dimeric forms. The structural superposition of these two forms reveals the role of Arg-376 in improving monomer performance. However, GCaMPJ seldom forms dimers under conditions similar to GCaMP3. St ructural and mutagenesis studies on Tyr-380 confirmed its importance in blocking the cpEGFP β-barrel holes. Our study proposes an efficient tool for mapping Ca(2+) signals in intact organs to facilitate the further improvement of GCaMP sensors.

ERp44 C160S/C212S mutants regulate IP3R1 channel activity

Previous studies have indicated that ERp44 inhibits inositol 1,4,5-trisphosphate (IP(3))-induced Ca(2+) release (IICR) via IP(3)R(1), but the mechanism remains largely unexplored. Using extracellular ATP to induce intracellular calcium transient as an IICR model, Ca(2+) image, pull down assay, and Western blotting experiments were carried out in the present study. We found that extracellular ATP induced calcium transient via IP(3)Rs (IICR) and the IICR were markedly decreased in ERp44 overexpressed Hela cells. The inhibitory effect of C160S/C212S but not C29S/T396A/ΔT(331-377) mutants of ERp44 on IICR were significantly decreased compared with ERp44. However, the binding capacity of ERp44 to L3V domain of IP(3)R(1) (1L3V) was enhanced by ERp44 C160S/C212S mutation. Taken together, these results suggest that the mutants of ERp44, C160/C212, can more tightly bind to IP(3)R(1) but exhibit a weak inhibition of IP(3)R(1) channel activity in Hela cells.

Change in TNF-? and IL-18 Levels in Serum of Rats with Acinetobacter baumannii Sepsis / 中华医院感染学杂志

OBJECTIVE To study the change and significance of TNF-? and IL-18 in the Acinetobacter baumannii sepsis. METHODS Sixty male SD rats were divided into 6 groups. The first group was normal control group. The second to sixth groups were sepsis groups which were killed at 4h,16h,24h,48h,72h after injecting A. baumannii through intraperitoneal injection to make sepsis model. The level of TNF-? and IL-18 in the serum of rats was measured by enzyme linked immunosorbent assay (ELISA). RESULTS The level of TNF-? in the serum increased markedly in the sepsis groups (P

Clinical Distribution and Drug Resistance of Pathogenic Bacteria in Septicemia / 中华医院感染学杂志

OBJECTIVE To investigate the distribution and drug resistance of pathogenic bacteria in septicemia in order to provide the reference for clinical antimicrobial agents usage.METHODS The blood samples of inpatients were cultured with blood culture apparatus,VITEK-AMS was used to identify the bacteria and conduct drug resistance test and ESBLs produced by Escherichia coli,and Klebsiella were detected by disc diffusion confirmatory test.RESULTS The 221 strains of pathogens that caused septicemia were mainly distributed in ICU,blood department and infection department.The 61 strains of E.coli were isolated,among which ESBLs were detected and accounted for 39.3%(24),26 strains of Klebsiella were isolated,among which ESBLs were detected and accounted for 26.9%(7),ESBLs strains were more resistant than ESBLs negative strains.Thirty two strains of Staphylococcus were isolated,among which MRS were detected and accounted for 62.5%(20).The pathogens showed highly multiple drug-resistance.Vancomycin and imipenem were the highest susceptible for Gram-positive and Gram-negative bacteria,respectively.CONCLUSIONS The pathogens that caused septicemia are mainly distributed in ICU,blood department and infection department.The situation of antibiotic resistance of pathogens is very serious now.Therefore,it is important to prevent the septicemia and to detect enzyme producing strains regularly for reference of reasonable antibiotic use.