title: Protective Effect of 2-Dodecyl-6-Methoxycyclohexa-2, 5-Diene-1, 4-Dione, Isolated from Averrhoa Carambola L., Against Palmitic Acid-Induced Inflammation and Apoptosis in Min6 Cells by Inhibiting the TLR4-MyD88-NF-κB Signaling Pathway.
abstract: OBJECTIVE
  Studies have demonstrated that 2-dodecyl-6-methoxycyclohexa-2, 5-diene-1, 4-dione (DMDD), isolated from the roots of Averrhoa carambola L., has significant therapeutic potential for the treatment of diabetes. However, the protective effect of DMDD against pancreatic beta cell dysfunction has never been reported. We investigated whether DMDD protected against palmitic acid-induced dysfunction in pancreatic β-cell line Min6 cells by attenuating the inflammatory response and apoptosis and to shed light on its possible mechanism.
  
  
  METHODS
  Cell viability was assessed by CCK-8. Glucose-stimulated insulin secretion levels and inflammatory cytokines levels were examined by ELISA. Apoptosis was assessed by Annexin V-FITC/PI Flow cytometry assay, Hoechst 33342/PI double-staining assay, and Transmission electron microscopy assay. Relative quantitative real-time PCR and western blot were used to determine the expressions of genes and proteins.
  
  
  RESULTS
  Cell viability and glucose-stimulated insulin secretion levels were increased in DMDD-pretreated Min6 cells. DMDD inhibited inflammatory cytokines IL-6, TNF-α and MCP-1 generations in palmitic acid (PA)-induced Min6 cells. Moreover, DMDD protected against PA-induced Min6 cells apoptosis and the expression of Cleaved-Caspase-3, -8 and -9 were down-regulated and the Bcl-2/Bax ratio was increased in DMDD-pretreated Min6 cells. In addition, the expression of TLR4, MyD88 and NF-κB were down-regulated in DMDD-pretreated Min6 cells and TAK-242-pretreated group cells.
  
  
  CONCLUSIONS
  DMDD protected Min6 cells against PA-induced dysfunction by attenuating the inflammatory response and apoptosis, and its mechanism of this protection was associated with inhibiting the TLR4-MyD88-NF-κB signaling pathway.
authors.affiliation: Pharmaceutical College, Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Qiuqiao
authors.initials: Q
authors.lastname: Xie
authors.forename: Shijun
authors.initials: S
authors.lastname: Zhang
authors.forename: Chunxia
authors.initials: C
authors.lastname: Chen
authors.forename: Juman
authors.initials: J
authors.lastname: Li
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Wei
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
authors.forename: Feifei
authors.initials: F
authors.lastname: Xuan
authors.forename: Ning
authors.initials: N
authors.lastname: Chen
authors.forename: Thithaihoa
authors.initials: T
authors.lastname: Pham
authors.forename: Ni
authors.initials: N
authors.lastname: Qin
authors.forename: Junhui
authors.initials: J
authors.lastname: He
authors.forename: Fangxing
authors.initials: F
authors.lastname: Ye
authors.forename: Wansu
authors.initials: W
authors.lastname: Huang
authors.forename: Renbin
authors.initials: R
authors.lastname: Huang
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Wen
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D065826:Averrhoa / Q000737:chemistry*; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D053138:Cyclohexenes / Q000302:isolation & purification / Q000494:pharmacology*; D005786:Gene Expression Regulation; D007249:Inflammation; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D019308:Palmitic Acid / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C581182:2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione; D000894:Anti-Inflammatory Agents, Non-Steroidal; C494827:Bax protein, mouse; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D053138:Cyclohexenes; D015850:Interleukin-6; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein; C577686:interleukin-6, mouse; C052617:Bcl2 protein, mouse; D019308:Palmitic Acid; D020169:Caspases