title: The toll-like receptor 4 antagonist transforming growth factor-β-activated kinase(TAK)-242 attenuates taurocholate-induced oxidative stress through regulating mitochondrial function in mice pancreatic acinar cells.
abstract: Acute pancreatitis (AP) is a commonly occurring and potentially life-threatening disease. Recently, toll-like receptor 4 (TLR4) has been considered as a new clue for studying the pathogenesis of AP due to its important role in inflammatory response cascade.
  
  
  
  The aim of this study was to investigate the potential protective effect of transforming growth factor-β-activated kinase (TAK)-242, a novel TLR4 antagonist, in taurocholate-treated mice pancreatic acinar cells. The protective effects were measured by cell viability, lactate dehydrogenase release and apoptosis, and oxidative stress was assayed by lipid peroxidation and oxidative enzyme activities. To determine the potential underlying mechanisms, mitochondrial cytochrome c release, swelling, and calcium buffering capacity were measured in isolated mitochondria, and mitochondrial biogenesis and expression of mitochondrial dynamic proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot.
  
  
  
  Treatment with 6-mM taurocholate significantly increased the expression of TLR4 at both mRNA and protein levels. TAK-242 markedly increased cell viability, decreased lactate dehydrogenase release, and inhibited apoptotic cell death as measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining in pancreatic acinar cells. These protective effects were accompanied by the suppressed lipid peroxidation and enhanced endogenous antioxidative enzyme activity. Using isolated and purified mitochondria from pancreatic acinar cells, we found that TAK-242 treatment also inhibited cytochrome c release into the cytoplasm, mitochondrial swelling, and decrease in mitochondrial Ca2+buffering capacity after taurocholate exposure. In addition, TAK-242 significantly promoted mitochondrial biogenesis, as evidenced by increased mtDNA and upregulated mitochondrial transcription factors. The results of Western blot analysis showed that TAK-242 also differently regulated the expression of mitochondrial fusion and fission proteins.
  
  
  
  All these data strongly indicated that blocking TLR4 activity via TAK-242 exerts protective effects in an in vitro AP model, and it could be a possible strategy to improve clinical outcome in AP patients.
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
authors.forename: Long-Fei
authors.initials: LF
authors.lastname: Pan
authors.affiliation: Department of Clinical Laboratory, Xi'an Medical College, Xi'an, Shaanxi, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
authors.forename: Jun-Tao
authors.initials: JT
authors.lastname: He
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
authors.forename: Jiang-Li
authors.initials: JL
authors.lastname: Sun
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Wang
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
authors.forename: Zheng-Hai
authors.initials: ZH
authors.lastname: Bai
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Su
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi, China. Electronic address: peihonghong_xjtu@126.com.
authors.forename: Hong-Hong
authors.initials: HH
authors.lastname: Pei
mesh_terms: D061354:Acinar Cells / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D020287:In Situ Nick-End Labeling; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010195:Pancreatitis / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D020011:Protective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013449:Sulfonamides / Q000494:pharmacology / Q000627:therapeutic use*; D013656:Taurocholic Acid; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors*
chemical_list: D015415:Biomarkers; D020011:Protective Agents; D013449:Sulfonamides; D051197:Toll-Like Receptor 4; C507035:ethyl 6-(N-(2-chloro-4-fluorophenyl)sulfamoyl)cyclohex-1-ene-1-carboxylate; D013656:Taurocholic Acid
keywords: Acute pancreatitis; Mitochondrial dysfunction; Oxidative stress; TLR4