Chaojin Chen

MG53 anchored by dysferlin to cell membrane reduces hepatocyte apoptosis which induced by ischaemia/reperfusion injury in vivo and in vitro

Hepatic ischaemia/reperfusion (HIR) induces severe damage on hepatocyte cell membrane, which leads to hepatocyte death and the subsequent HIR injury. In this study, we investigated the role and the mechanism of mitsugumin‐53 (MG53), a novel cell membrane repair protein, in protecting the liver against HIR injury. Rats were subjected to sham operation or 70% warm HIR with or without recombined MG53 (rhMG53), caudal vein‐injected 2 hrs before inducing HIR. In vitro, cultured hepatocyte AML12 cells were subjected to hypoxia/reoxygenation (H/R) in the presence of rhMG53 and/or dysferlin gene shRNAs or adenovirus transfection. HIR resulted in severe liver injury manifested as severe liver histological changes and increased AST and ALT release. Post‐ischaemic hepatic oxidative stress was significantly enhanced demonstrated by elevated dihydroethidium level, increased 4‐hydroxynonenal, enhanced 15‐F2t‐isoprostane and decreased SOD activity. rhMG53 administration attenuated post‐HIR liver injury, decreased liver oxidative stress and further enhanced dysferlin protein expression and its colocalization with MG53. Similarly, H/R induced AML12 cell injury and oxidative stress, which were abolished by either rhMG53 or dysferlin overexpression but were exacerbated by dysferlin gene knockdown. Dysferlin overexpression further increased H/R‐induced increased colocalization of MG53 and dysferlin. In conclusion, MG53 was anchored by dysferlin to reduce oxidative stress and cell death and attenuate HIR injury.

Dexmedetomidine improves gastrointestinal motility after laparoscopic resection of colorectal cancer: A randomized clinical trial.

Background:To investigate the effects of intraoperative application of dexmedetomidine (Dex) on early gastrointestinal motility after laparoscopic resection of colorectal cancer. Methods:In this prospective, randomized double-blind investigation, 60 patients who underwent laparoscopic resection of colorectal cancer were randomly allocated to receive Dex (DEX group, n = 30) or saline (CON group, n = 30). In the DEX group, Dex was loaded (1 &mgr;g/kg) before anesthesia induction and was infused (0.3 &mgr;g/kg/h) during surgery. Time to postoperative first flatus (FFL) and first feces (FFE), and time to regular diet were recorded. Serum diamine oxidase (DAO) activity and intestinal fatty acid-binding protein (I-FABP) were detected. Results:Both the time to the FFL (44.41 ± 4.51 hours vs 61.03 ± 5.16 hours, P = 0.02) and the time to the FFE (60.67 ± 4.94 hours vs 82.50 ± 6.88 hours, P = 0.014) were significantly shorter in the DEX group than the CON group. Furthermore, the time to regular diet of the DEX group was shorter than that of the CON group (76.15 ± 4.11 hours vs 91.50 ± 5.70 hours, P = 0.037). Both DAO and I-FABP increased significantly from beginning of surgery to postoperative day 1 in the CON group (2.49 ± 0.41 ng/mL vs 4.48 ± 0.94 ng/mL for DAO, P = 0.028, 1.32 ± 0.09 ng/mL vs 2.17 ± 0.12 ng/mL for I-FABP, P = 0.045, respectively), whereas no significant change was observed in the DEX group. Furthermore, patients in the DEX group had stable hemodynamics and shorter hospital stay than those in the CON group. Conclusion:Dex administration intraoperatively benefits recovery of gastrointestinal motility function after laparoscopic resection of colorectal cancer with stable hemodynamics during surgery though further studies are needed to explore the mechanisms of Dex on gastrointestinal motility.

SERPINB1 ameliorates acute lung injury in liver transplantation through ERK1/2-mediated STAT3-dependent HO-1 induction

Background Postoperative acute lung injury (ALI) is a severe complication after liver transplantation, which severely affects postoperative patients’ survival. The underlying mechanism is largely unknown and effective treatment limited. We explored the role of serpin protease inhibitor B1 (SERPINB1), a potent inhibitor of neutrophil serine proteases, in ALI in liver transplantation and its interplay with signal transducer and activator of transcription 3 (STAT3) and heme oxygenase‐1 (HO‐1). Methods Sprague‐Dawley rats underwent orthotopic autologous liver transplantation (OALT) were treated with recombinant SB1 (rSB1) in the absence or presence of STAT3 specific inhibitor, WP1066. Then SB1‐siRNA was used to knockdown endogenous SERPINB1. Also, alveolar epithelial cells RLE‐6TN and BEAS‐2B were exposed to TNF‐&agr; without or with SERPINB1 and the roles of STAT3 and HO‐1 were examined by respective gene knockdown. Finally, rats were treated with ERK1/2 inhibitor U0126, p38 MAPK inhibitor SB20358, or JNK inhibitor SP600125 after rSB1 pretreatment and then subjected to OALT. Results OALT resulted in increased pulmonary inflammation and oxidative stress, accompanied by severe lung injury that was coincident with increased pulmonary SERPINB1, HO‐1, and STAT3. SERPINB1 gene knockdown increased post‐OALT lung injury and pulmonary inflammation. rSB1 administration dose‐dependently reduced post‐OALT lung injury and decreased pulmonary inflammation and oxidative stress with concomitant enhanced HO‐1 and STAT3 protein expression. These protective effects of SERPINB1 were abolished by STAT3 inhibition. Similarly, in RLE‐6TN cells and BEAS‐2B cells, TNF‐&agr; induced cell injury and increased HO‐1 and STAT3. SERPINB1 further increased HO‐1 and STAT3 protein expression and attenuated TNF‐&agr;‐induced cellular oxidative stress, apoptotic cells, and mitochondria damage, which were cancelled by STAT3 or HO‐1 gene knockdown. Furthermore, these SERPINB1‐mediated STAT3/HO‐1 activation and pulmonary protective effects were abolished by inhibition of ERK1/2 but not p38 MAPK or JNK. Conclusions SERPINB1 decreased inflammation, ameliorated oxidative stress in the lung, and attenuated ALI in rats with OALT by activating HO‐1 and it does so through STAT3 and it does so by activating ERK1/2. Graphical abstract Figure. No Caption available. HighlightsLung SERPINB1 is pulmonary protective against acute lung injury.STAT3/HO‐1 activation is the major mechanism in SERPINB1‐mediated pulmonary protection.ERK1/2 mediated SERPINB1‐induced STAT3/HO‐1 activation in the lung.

Asymmetric dimethylarginine and all-cause mortality: a systematic review and meta-analysis

Asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), impairs the beneficial effect of NO. The predictive value of ADMA for all-cause mortality remains controversial, though it is important in the development of cardiovascular disease (CVD) and progression to dialysis in renal disease. This systematic review and meta-analysis was conducted to investigate the association between circulating ADMA and all-cause mortality. Studies with data pertinent to the association between circulating ADMA and all-cause mortality were reviewed and OR, HR or RR with 95% CI derived from multivariate Cox’s proportional-hazards analysis were extracted. A total of 34 studies reporting 39137 participants were included in final analysis. The results demonstrated that circulating ADMA was independently associated with all-cause mortality (RR = 1.27, 95% CI: 1.20–1.34). The association was still statistically significant in patients with pre-existing renal disease (RR = 1.30, 95% CI: 1.19–1.43) and pre-existing CVD (RR = 1.26, 95% CI: 1.16–1.37). In those without pre-existing renal or CVD, ADMA also predicted all-cause mortality (RR = 1.31, 95% CI: 1.13–1.53). The present study suggests a positive association of circulating ADMA with all-cause mortality. Further studies are needed to investigate the effects of interventions on ADMA, and the value of ADMA as a biomarker.

Identification of key genes and pathways associated with neuropathic pain in uninjured dorsal root ganglion by using bioinformatic analysis

Purpose Neuropathic pain is a complex chronic condition occurring post-nervous system damage. The transcriptional reprogramming of injured dorsal root ganglia (DRGs) drives neuropathic pain. However, few comparative analyses using high-throughput platforms have investigated uninjured DRG in neuropathic pain, and potential interactions among differentially expressed genes (DEGs) and pathways were not taken into consideration. The aim of this study was to identify changes in genes and pathways associated with neuropathic pain in uninjured L4 DRG after L5 spinal nerve ligation (SNL) by using bioinformatic analysis. Materials and methods The microarray profile GSE24982 was downloaded from the Gene Expression Omnibus database to identify DEGs between DRGs in SNL and sham rats. The prioritization for these DEGs was performed using the Toppgene database followed by gene ontology and pathway enrichment analyses. The relationships among DEGs from the protein interactive perspective were analyzed using protein–protein interaction (PPI) network and module analysis. Real-time polymerase chain reaction (PCR) and Western blotting were used to confirm the expression of DEGs in the rodent neuropathic pain model. Results A total of 206 DEGs that might play a role in neuropathic pain were identified in L4 DRG, of which 75 were upregulated and 131 were downregulated. The upregulated DEGs were enriched in biological processes related to transcription regulation and molecular functions such as DNA binding, cell cycle, and the FoxO signaling pathway. Ctnnb1 protein had the highest connectivity degrees in the PPI network. The in vivo studies also validated that mRNA and protein levels of Ctnnb1 were upregulated in both L4 and L5 DRGs. Conclusion This study provides insight into the functional gene sets and pathways associated with neuropathic pain in L4 uninjured DRG after L5 SNL, which might promote our understanding of the molecular mechanisms underlying the development of neuropathic pain.

Overexpression of Brg1 Alleviates Hepatic Ischemia/Reperfusion-Induced Acute Lung Injury through Antioxidative Stress Effects

Aim To investigate whether overexpression of Brahma-related gene-1 (Brg1) can alleviate lung injury induced by hepatic ischemia/reperfusion (HIR) and its precise mechanism. Methods Cytomegalovirus-transgenic Brg1-overexpressing (CMV-Brg1) mice and wild-type (WT) C57BL/6 mice underwent HIR. Lung histology, oxidative injury markers, and antioxidant enzyme concentrations in the lung were assessed. The protein expression levels of Brg1, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NAD(P)H:quinone oxidoreductase 1 (NQO1) in the lung were analyzed by Western blotting. Results In the WT group, histopathological analysis revealed that lung damage peaked at 6 h after HIR. Meanwhile, the lung reactive oxygen species (ROS) and 8-isoprostane levels were significantly increased. The protein expression of Brg1 in lung tissue decreased to a minimum at 6 h. Overexpression of Brg1 alleviated lung injury and decreased the amounts of oxidative products, including the levels of 8-isoprostane and ROS, as well as the percentage of positive cells for 4-hydroxynonenal (4-HNE) and 8-oxo-2′-deoxyguanosine (8-OHdG). Brg1 overexpression increased the expression and nuclear translocation of Nrf2 as well as activated the antioxidases. In addition, it decreased the expression of inflammatory factors. Conclusion Overexpression of Brg1 alleviates oxidative lung injury induced by HIR, likely through the Nrf2 pathway.

Propofol post-conditioning alleviates hepatic ischaemia reperfusion injury via BRG1-mediated Nrf2/HO-1 transcriptional activation in human and mice

To explore the effects of propofol post‐conditioning (PPC) on hepatic ischaemia/reperfusion injury (HIRI) and the potential mechanisms that might be involved in the interaction of Brahma‐related gene1(BRG1) and Nuclear‐related factor 2(Nrf2). Patients were randomized into PPC(n = 16) and non‐PPC(NPC)( n = 21) groups. Propofol(2 mg/kg) was infused within 10 min. of the onset of liver reperfusion during liver transplantation in the PPC group. Liver function tests, as well as Brg1, Nrf2, Heme oxygenase‐1(HO‐1) and NADPH:quinone oxidoreductase1(NQO1) expression levels were evaluated. CMV‐Brg1 mice were designed to investigate the role of Brg1 overexpression during HIRI. Brg1 and Nrf2 siRNA were used to examine the relationship between Brg1 and Nrf2/HO‐1 pathways in propofol‐mediated effects in a human hepatocyte(L02) hypoxia/reoxygenation(H/R) model. In patients, PPC attenuated both donor liver pathological and function injury, and reducing oxidative stress markers, compared to the NPC group, 24 hrs after surgery. PPC increased liver Brg1, Nrf2, HO‐1 and NQO1 expression. In mice, PPC reduced HIRI by decreasing liver oxidative stress and activating Nrf2/HO‐1 pathway, accompanied by up‐regulation of BRG1 expression. BRG1 overexpression activated Nrf2/HO‐1 transcription in CMV‐BRG1 mice during HIRI. In vitro, PPC significantly elevated expression of Nrf2, HO‐1 and NQO1, resulting in a reduction of cell DCFH‐DA and 8‐isoprostane levels and decreased lactate dehydrogenase levels, leading to an overall increase in cell viability. Moreover, the protective effects of propofol were partially abrogated in Nrf2‐knock‐down or BRG1‐knock‐down hepatocytes. Nrf2‐knock‐down drastically reduced protein expression of HO‐1 and NQO1, while Brg1‐knock‐down decreased HO‐1 expression. Propofol post‐conditioning alleviates HIRI through BRG1‐mediated Nrf2/HO‐1 transcriptional activation.

Intravenous Anesthetic Protects Hepatocyte from Reactive Oxygen Species-Induced Cellular Apoptosis during Liver Transplantation In Vivo

Background Liver transplantation leads to liver ischemia/reperfusion (I/R) injury, resulting in early graft dysfunction and failure. Exacerbations of oxidative stress and inflammatory response are key processes in the development of liver I/R injury. Intravenous anesthetic propofol potent effects on free radical scavenging and protects livers against I/R injury. However, the role and mechanism of propofol-mediated hepatic protection in liver transplantation is poorly understood. The aim of this study was to evaluate the role of propofol postconditioning in the liver I/R injury after liver transplantation. Methods Forty-eight rats were randomly divided into six groups: rats receiving either sham operation or orthotopic autologous liver transplantation (OALT) in the absence or presence of propofol (high dose and low dose) postconditioning or intralipid control or VAS2870 (Nox2 special inhibitor). Eight hours after OALT or sham operation, parameters of organ injury, oxidative stress, inflammation, and NADPH-associated proteins were assessed. Results After OALT, severe liver pathological injury was observed that was associated with increases of serum AST and ALT, which were attenuated by propofol postconditioning. In addition, especially high dose of propofol postconditioning reduced TNF-α, IL-1β, IL-6, TLR4, and NF-κB inflammatory pathway, accompanied with decrease of neutrophil elastase activity, MPO activity, 8-isoprotane, p47phox and gp91phox protein expressions, and increase of SOD activity. Inhibition of Nox2 by VAS2870 conferred similar protective effects in liver transplantation. Conclusion Liver transplantation leads to severe inflammation and oxidative stress with NADPH oxidase activation. Propofol postconditioning reduces liver I/R injury after liver transplantation partly via inhibiting NADPH oxidase Nox2 and the subsequent inflammation and oxidative stress.

Connexin32 plays a crucial role in ROS-mediated endoplasmic reticulum stress apoptosis signaling pathway in ischemia reperfusion-induced acute kidney injury

BackgroundIschemia–reperfusion (I/R)-induced acute kidney injury (AKI) not only prolongs the length of hospital stay, but also seriously affects the patient’s survival rate. Although our previous investigation has verified that reactive oxygen species (ROS) transferred through gap junction composed of connexin32 (Cx32) contributed to AKI, its underlying mechanisms were not fully understood and viable preventive or therapeutic regimens were still lacking. Among various mechanisms involved in organs I/R-induced injuries, endoplasmic reticulum stress (ERS)-related apoptosis is currently considered to be an important participant. Thus, in present study, we focused on the underlying mechanisms of I/R-induced AKI, and postulated that Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI.MethodsWe established renal I/R models with Cx32+/+ and Cx32−/− mice, which underwent double kidneys clamping and recanalization. ROS scavenger (N-acetylcysteine, NAC) and ERS inhibitors (4-phenyl butyric acid, 4-PBA, and tauroursodeoxycholic acid, TUDCA) were used to decrease the content of ROS and attenuate ERS activation, respectively.ResultsRenal damage was progressively exacerbated in a time-dependent manner at the reperfusion stage, that was consistent with the alternation of ERS activation, including glucose regulated protein 78 (BiP/GRP78), X box-binding protein1, and C/EBP homologous protein expression. TUDCA or 4-PBA application attenuated I/R-induced ERS activation and protected against renal tubular epithelial cells apoptosis and renal damage. Cx32 deficiency decreased ROS generation and distribution between the neighboring cells, which attenuated I/R-induced ERS activation, and improved cell apoptosis and renal damage.ConclusionCx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI. Cx32 deficiency, ROS elimination, and ERS inhibition all could protect against I/R-induced AKI.

Identification of potential mechanism and hub genes for neuropathic pain by expression-based genome-wide association study: GU et al.

Neuropathic pain (NP) is a common pathological pain state with limited effective treatments. This study was designed to identify potential mechanisms and candidate genes using gene expression–based genome‐wide association study (eGWAS). All NP‐related microarray experiments were obtained from Gene Expression Omnibus and ArrayExpress. Significantly dysregulated genes were identified between experimental and untreated groups, and the number of microarray experiments in which each gene was dysregulated was calculated. Significantly dysregulated genes were ranked according to P values of the chi‐square test. Using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database, we performed functional and pathway enrichment analysis. Protein‐protein interaction (PPI) network and module analysis was performed using Cytoscape software. A total of 115 candidate genes were identified from 19 independent microarray experiments by eGWAS based on the Bonferroni threshold ( P < 2.97 × 10 −6). Immune and inflammatory responses, and complement and coagulation cascades, were respectively the most enriched biological process and pathways for candidate genes. The hub genes with highest connectivity in PPI network and two modules Ccl2 and Jun, and Ctss application of the eGWAS methodology can identify mechanisms and candidate genes associated with NP. Our results support the validity and prevalence of inflammatory and immune mechanisms across different NP models, and Ccl2, Jun, and Ctss may be the hub genes for NP.