title: [Effects of α3 neuronal nicotinic acetylcholine receptor on cell apoptosis and p38 MAPK signal transduction pathway in SH-SY5Y cells].
abstract: OBJECTIVE
  To investigate the effects of α3 neuronal nicotinic acetylcholine receptor (nAChR) on apoptosis and p38 signal transduction pathway in SH-SY5Y cells and to assess the roles of α3 nAChR in the pathogenesis of Alzheimer's disease (AD).
  
  
  METHODS
  The levels of α3 nAChR mRNA and protein were measured by real-time PCR and Western blot, respectively, in SH-SY5Y cells transfected with α3 nAChR siRNA. The mRNA level of bcl-2 and bax was measured by the real-time PCR. The siRNA transfected SH-SY5Y cells and control were then treated with 10 µmol/L Aβ25-35 for another 48 h, and the change in apoptotic rate and the levels of p-p38 and p38 were measured by flow cytometry and Western blot. Subsequently these SH-SY5Y cells were exposed to a blocker of p38 protein, and the apoptotic rate was measured again.
  
  
  RESULTS
  Compared to the controls, the expression of α3 nAChR at mRNA and protein levels in the SH-SY5Y cells transfected with α3 nAChR siRNA decreased by 95% and 86%, respectively; the mRNA levels of bax increased 2.11 times and that for bcl-2 decreased 0.53 times. The apoptotic rate was unaffected (3.40% ± 0.20%); but it increased after Aβ25-35 treatment (24.52% ± 1.59%); the level of p-p38 protein also increased by 178% in the α3 nAChR inhibited cells treated with Aβ25-35. Compared to controls, the Aβ25-35-treated SH-SY5Y cells and the Aβ25-35-treated and siRNA-transfected cells both showed a reduction in apoptosis after treatment with p38 blocker, especially in the former.
  
  
  CONCLUSIONS
  The siRNA silencing of α3 nAChR mRNA may enhance the effect of Aβ25-35 on the cell apoptosis by increasing the levels of p38 protein and bax mRNA and decreasing the level of bcl-2 mRNA, which may play a role in the pathogenesis of AD.
authors.affiliation: Guiyang Medical University, Guiyang, China.
authors.forename: Xue-ling
authors.initials: XL
authors.lastname: Zhang
authors.forename: Xiao-lan
authors.initials: XL
authors.lastname: Qi
authors.forename: Jia-mou
authors.initials: JM
authors.lastname: Ren
authors.forename: Chang-xue
authors.initials: CX
authors.lastname: Wu
authors.forename: Zhi-zhong
authors.initials: ZZ
authors.lastname: Guan
mesh_terms: D000544:Alzheimer Disease / Q000209:etiology; D016229:Amyloid beta-Peptides / Q000378:metabolism; D017209:Apoptosis; D045744:Cell Line, Tumor; D020868:Gene Silencing; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology*; D010446:Peptide Fragments / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011978:Receptors, Nicotinic / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011978:Receptors, Nicotinic; D051028:bcl-2-Associated X Protein; D048051:p38 Mitogen-Activated Protein Kinases; C074636:amyloid beta-protein (25-35)