Objective To investigate the cross-talk between extracellular signal-regulated kinase (ERK) and nuclear factor κB (NF-κB) signal transduction pathways in A375 human melanoma cells.Methods Cultured A375 cells were randomly divided into 5 groups:control group receiving no treatment,two U0126 (a selective inhibitor of the ERK signaling pathway) groups treated with U0126 of 10 and 5 μmol/L,and two BMS-345541 groups treated with BMS-345541 of 10 and 5 μmol/L.After 24-hour treatment,Western blot and reverse transcription PCR were performed to measure the protein expressions of NF-κB P65,phosphorylated IκBα (p-IκBα),ERK1/2,as well as p-ERK1/2,and the mRNA expressions of NF-κB P65 and ERK1,respectively.One-way analysis of variance and least significant difference (LSD)-t test were carried out for statistical analysis.Results After 24 hours of treatment with U0126 of 10 and 5 μmol/L,a significant decrease was noted in the relative expression level of NF-κB p65 protein (0.60 ± 0.04 and 0.56 ± 0.06 vs.1.54 ± 0.15,both P＜ 0.01) and mRNA (0.79 ± 0.05 and 0.75 ± 0.04 vs.0.86 ± 0.05,both P ＜ 0.01),but a statistical increase in that of p-IκBα protein (0.90 ± 0.05 and 0.70 ± 0.02 vs.0.61 ± 0.03,both P ＜ 0.01) in the two U0126 groups compared with the control group; significant differences were observed in the expression level of p-IκBo protein (P ＜ 0.01) but not in that of NF-κB p65 protein (P ＞ 0.01) between the two U0126 groups.The relative expression levels of ERK1/2 and p-ERK1/2 proteins as well as ERK1 mRNA were significantly higher in the control A375 cells than those in the cells treated with BMS-345541 of 10 μmol/L (0.73 ± 0.07,0.75 ± 0.09,1.51 ± 0.02,all P ＜ 0.01),but similar to those treated with BMS-345541 of 5 μmol/L (0.94 ± 0.11,0.99 ± 0.04,1.62 ± 0.03,all P ＞ 0.05).Conclusion There is a cross-talk between ERK and NF-κB signal transduction pathways in A375 melanoma cells.

Objective:To explore the effect and possible mechanism of normal temperature mechanical perfusion(NMP)plus bone marrow mesenchymal stem cells(BMMSCs)on early endoplasmic reticulum stress(ERs)and cellular apoptosis after donation after cardiac death(DCD)donor liver transplantation.Methods:BMMSCs were isolated and cultured by adherence method.Sixty Sprague-Dawley(SD)rats were randomly divided into five groups of sham operation(sham), static cold storage(SCS), NMP, BMMSC and NMP plus BMMSCs(BP)( n=12 each). Liver tissue and serum sample of each group were harvested at Day 1/7 post-operation.Hematoxylin-eosin(HE)staining was employed for observing pathological changes of liver tissue; TdT-mediated dUTP nick end labeling(TUNNEL)staining for detecting cellular apoptosis; immunohistochemistry for detecting the expression of hepatocyte transcription factor C/EBP homologous protein(CHOP); Western blot for detecting the expressions of GRP-78, p-PERK, ATF4, CHOP and cleaved caspase-3. Results:Compared with SCS group, hepatic injury and inflammation significantly declined in NMP, BMMSC and BP groups and improvement of hepatic injury was the most pronounced in BP group.Cellular apoptosis lessened markedly in BP group at Day 1/7 as compared with SCS group and the difference was statistically significant.The expressions of ERs-related proteins GRP-78, p-PERK and ATF4 spiked in SCS group and the expressions of pro-apoptotic proteins CHOP and cleaved caspase-3 were significantly elevated and declined markedly in BP group.And the difference was statistically significant.Conclusions:BMMSCs plus NMP can significantly improve hepatocyte apoptosis and inflammatory response after DCD donor liver transplantation.And its mechanism may be correlated with suppressing early endoplasmic reticulum stress of hepatocytes.

Objective:To investigate the role of ferroptosis in bone marrow mesenchymal stem cells (BMMSCs) combine with normothermic machine perfusion (NMP) in repairing steatotic liver donor after cardiac death (DCD) in SD rats.Methods:BMMSCs were derived from SD rats to establish the DCD model of rats steatotic liver. A total of 24 rats were randomly divided into four groups: simple steatotic liver model group (Sham), static cold storage group (SCS), NMP, BMMSCs combine with NMP preservation group (BNMP), and the preservation time was 4 hours. The donor liver function was evaluated by liver structure, liver enzymes and lactic acid content of perfusion fluid, bile secretion and inflammatory cytokines; furthermore, in order to evaluate the occurrence of liver ferroptosis, the content of Fe 2+, malondialdehyde and glutathione (GSH) in liver tissue, as well as the mRNA or protein expression changes of cyclooxygenase-2 (COX-2), prostaglandin-endoperoxide synthase 2 (Ptgs2), glutathione peroxidase 4 (GPX4) and ferritin heavy chain 1 (FTH1) were detected. Results:After DCD steatotic donor liver was preserved for 4 hours, the liver injury, pro-inflammatory and anti-inflammatory cytokines expression in the BNMP and NMP groups were better than those in the SCS group. During the machine perfusion preservation period, alanine aminotransferase [(189.0±12.5)U/L vs. (227.7±16.2)U/L], aspartate aminotransferase [(207.3±18.6)U/L vs. (247.0±11.8)U/L] and lactic acid [(2.3±0.3)mmol/L vs. (2.9±0.2)mmol/L] in the BNMP group is lower than those in NMP group, moreover, the amount of hepatic bile secretion in the BNMP group [(1 245.7±46.8) μl vs. (1 014.3±67.9) μl] was more than that in NMP group, the difference was statistically significant (all P<0.05). The content of Fe 2+ and malondialdehyde in the liver tissue of BNMP group was significantly lower than those of SCS and NMP groups, on the contrary, the content of GSH was significantly higher than those of SCS and NMP groups. In addition, in the BNMP group, the mRNA level of Ptgs2 and protein level of COX-2 in the liver were significantly reduced, and expression of GPX4 and FTH1 were significantly higher than those of NMP and SCS groups, the differences were statistically significant (all P<0.05). Conclusion:BMMSCs combine with normothermic machine perfusion can better repair SD rats DCD steatotic donor liver and its mechanism of action may be related to its regulation on liver ferroptosis.

Objective:To investigate the effect of heme oxygenase-1 (HO-1) modified bone marrow mesenchymal stem cells (BMMSCs) combined with normothermic machine perfusion (NMP) on the intestinal barrier function in rats with acute rejection of liver transplantation.Methods:Specific pathogen free 2 male Brown Norway (BN) rats (4-5 weeks, 40-60 g) were used to isolat BMMSCs, and HO-1 was infected by adenovirus. Of 24 male Lewis rats (7-8 weeks old, 200-220g) were used as donors, 30 male BN rats (8-9 weeks old, 220-240 g) were used as recipients. Acute rejection models of orthotopic liver transplantation were established in rats using two cuff technique. BN recipient rats were randomly divided into five groups: sham group, abdomen of the mice was open and closed within 30 min; NMP livers were simply mechanically perfused for 4 h; the BMP group were perfused with BMMSCs through the portal vein; the HBP group were perfused with HO-1/BMMSCs through the portal vein; the FK506 livers were mechanically perfused for 4 h and administered intragastrically of tacrolimus daily following surgery, 6 per group, on days 14 after surgery, the relevant indicators were taken and the rejection activity index (RAI) changes were investigated. The changes of intestinal pathological were analyzed by HE staining and transmission electron microscope, the expression levels of zonula occludens-1 (ZO-1) and occludin protein in intestinal tissue were detected by Western blotting, the concentrations of lipopolysaccharide, D-lactic acid and diamine oxidase (DAO) in serum were detected by ELISA.Results:The RAI of HBP group (2.80±0.84) and FK506 group (2.20±0.84) were significantly lower than that of NMP group (7.60±1.14) and BMP group (6.00±1.58), the differences were statistically significant (all P<0.05). The intestinal villi in NMP group were significantly sparse, wrinkled and disorderly arranged while the degree of intestinal injury in BMP group, HBP group and FK506 group were more mitigated. Electron microscope observation showed that the microvilli of intestinal epithelial cells in HBP group were rich and orderly, and the tight junction structure between cells was complete. The protein expression levels of ZO-1 and Occludin in the intestinal tissues of HBP group [(0.87±0.06) (1.28±0.26)] were higher than those of NMP group [(0.41±0.12) (0.27±0.18)] and FK506 group [(0.52±0.15) (0.63±0.22)], the differences were statistically significant (all P<0.05). The concentration of lipopolysaccharide, D-lactic acid and DAO in serum of HBP group was lower than those of NMP group and FK506 group, the differences were statistically significant (all P<0.05). Conclusion:HO-1/BMMSCs combined with NMP protects the intestinal mucosal barrier function of BN rats with acute rejection after liver transplantation.