title: LPS-induced proNGF synthesis and release in the N9 and BV2 microglial cells: a new pathway underling microglial toxicity in neuroinflammation.
abstract: OBJECTIVE
  While aberrant activation of microglial cells was evidently involved in neuroinflammation and neurotoxicity in the neurodegenerative diseases such as Alzheimer's and Parkinson's disease, objective of study was to address if activated microglias deliver their effect by releasing pro-neurotrophins.
  
  
  METHODS
  By in vitro culture of N9 and BV2 cell lines and lipopolysaccharide (LPS) stimulation model, generation and release of proNGF, proBDNF and MMP-9 was studied in the activated microglial cells by immunocytochemistry, western blotting and bioassay methods.
  
  
  RESULTS
  Activation of microglial cells was observed with obvious increasing iba1-immunoreactivity following LPS stimulation in cell culture. Synthesis and up-regulation of proNGF protein significantly occurred in N9 and BV2 cells 12h-48h after LPS exposure, whereas no significant changes of proBDNF and MMP9 were observed in these microglial cell lines with LPS insult. More interestingly, extracellular release or secretion of proNGF molecule was also detected in culture medium of N9 cells after LPS stimulation. Finally, bioassay using MTT, Hoechst/PI and TUNEL staining in SH-SY5Y cells further confirmed that proNGF treatment could result in apoptotic cell death but it did not significantly influence cell viability of SH-SY5Y cells.
  
  
  CONCLUSIONS
  This in vitro study revealed LPS-stimulated proNGF synthesis and release in activated N9/BV2 microglial cell lines, also suggesting that proNGF may appeal a new pathway or possible mechanism underlying microglial toxicity in the neuroinflammation and a potential target for therapeutic manipulation of the neurodegenerative diseases.
authors.affiliation: Institute of Neurosciences, The Fourth Military Medical University, Xi'an, China.
authors.forename: Li
authors.initials: L
authors.lastname: Duan
authors.forename: Bei-Yu
authors.initials: BY
authors.lastname: Chen
authors.forename: Xiao-Long
authors.initials: XL
authors.lastname: Sun
authors.forename: Zhuo-Jing
authors.initials: ZJ
authors.lastname: Luo
authors.forename: Zhi-Ren
authors.initials: ZR
authors.lastname: Rao
authors.forename: Jing-Jie
authors.initials: JJ
authors.lastname: Wang
authors.forename: Liang-Wei
authors.initials: LW
authors.lastname: Chen
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018613:Microscopy, Confocal; D020932:Nerve Growth Factor / Q000096:biosynthesis*; D019636:Neurodegenerative Diseases / Q000378:metabolism / Q000473:pathology; D020078:Neurogenic Inflammation / Q000378:metabolism / Q000473:pathology; D011498:Protein Precursors / Q000096:biosynthesis* / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D008070:Lipopolysaccharides; D011498:Protein Precursors; C489226:pro-nerve growth factor, mouse; D020932:Nerve Growth Factor; D020780:Matrix Metalloproteinase 9
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