title: iTRAQ-based proteomic analysis of tetramethylpyrazine inhibition on lipopolysaccharide-induced microglial activation.
abstract: OBJECTIVE
  Neurodegenerative diseases are the leading cause of morbidity and mortality worldwide. Several studies have shown that tetramethylpyrazine (TMP) is an effective therapy for neurodegenerative diseases and that it acts by inhibiting the activation of microglial cells in response to inflammatory stimuli. However, the molecular mechanisms underlying the action of TMP remain unknown.
  
  
  METHODS
  Proteomic analysis was used to generate novel insights into the mechanism by which TMP inhibits microglial activation, and western blotting was used to validate candidate proteins.
  
  
  RESULTS
  To identify candidate proteins affected by TMP in lipopolysaccharide-activated microglia, we performed proteomic analysis using iTRAQ labelling coupled with LC TRIPLE-TOF, and we identified 5187 unique proteins. Among these, 266 proteins were differentially expressed and considered putative candidate proteins. Protein annotation revealed that the differentially expressed proteins, such as inducible nitric oxide synthase (iNOS) and ERO1-like protein (ERO1L), might be involved in reducing cellular oxidation in response to stress. Ingenuity pathway analysis revealed that the differentially expressed proteins were involved in a variety of signalling pathways, including liver X receptor/retinoid X receptor (LXR/RXR) activation and the production of nitric oxide and reactive oxygen species in macrophages. Furthermore, one of the differentially expressed protein candidates detected by iTRAQ, iNOS, was confirmed by western blotting.
  
  
  CONCLUSIONS
  Our data suggest that iTRAQ technology is an effective tool to study the mechanism by which TMP inhibits activated microglia. TMP decreased the expression of LXR/RXR-mediated iNOS, which reduced microglial activation in response to inflammatory stimuli.
authors.affiliation: Institute of Life Science and School of Public Health, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Qiang-Hong
authors.initials: QH
authors.lastname: Pu
authors.affiliation: Institute of Life Science and School of Public Health, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Jun-Lin
authors.initials: JL
authors.lastname: He
authors.affiliation: Institute of Life Science and School of Public Health, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Ming-Jun
authors.initials: MJ
authors.lastname: Wu
authors.affiliation: Institute of Life Science and School of Public Health, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Jia-Jia
authors.initials: JJ
authors.lastname: Li
authors.affiliation: Institute of Life Science and School of Public Health, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Institute of Life Science and School of Public Health, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Ying-Xiong
authors.initials: YX
authors.lastname: Wang
authors.affiliation: Institute of Life Science and School of Public Health, Chongqing Medical University, Chongqing 400016, PR China. Electronic address: yuchaom@163.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Yu
mesh_terms: D000818:Animals; D002460:Cell Line; D015870:Gene Expression / Q000187:drug effects; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects*; D051379:Mice; D017628:Microglia / Q000187:drug effects*; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000235:genetics; D040901:Proteomics / Q000379:methods*; D011719:Pyrazines / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D008070:Lipopolysaccharides; D011719:Pyrazines; D052247:Nitric Oxide Synthase Type II; C017953:tetramethylpyrazine
keywords: ITRAQ; Microglia; Neurodegenerative diseases; Proteomics; Tetramethylpyrazine