title: [Protection of HSF1/HSP70 pathway on UVA-induced HaCaT cells apoptosis via inhibiting the activation of c-Jun N-terminal kinase].
abstract: OBJECTIVE
  To investigate the protective effect of heat shock factor1 (HSF1) and heat shock protein70 (HSP70) on ultraviolet A (UVA)-induced HaCaT cells apoptosis and its mechanism.
  
  
  METHODS
  The apoptotic HaCaT cell model was induced by UVA irradiation (8mJ/cm2). The cells were randomly divided into three groups, including a control group, a model group (8mJ/cm2 UVA) and a HSP70 transcription inhibitor group (50 micromol/L quercetin). The morphologic alteration of apoptotic cells was investigated by using Hoechst 33258 fluorescent staining. Western blotting was used to investigate protein expression levels of phosphorylated HSF1 and HSP70 at different time points, as well as c-Jun N-terminal kinase (JNK) and phosphorylated JNK were investigated after incubating for 6 hours following UVA irradiation. HSP70 mRNA was detected by Real-Time PCR.
  
  
  RESULTS
  Protein expression levels of both phosphorylated HSF1 and HSP70 were time-dependent, appearing an increase at first and then decreased. The increase of p-HSF1 begining at 1h, up to the peak at 3h; and the increase of HSP70 to the peak at 6h and then recovered to the original level at 24h. The pretreatment of HSP70 transcription inhibitor quercetin could significantly inhibit the expression of HSP70 mRNA., and increase the expression of phosphorylated JNK, while increase the apoptosis rate in comparison with UVA model group observed by using Hoechst 33258 fluorescent staining.
  
  
  CONCLUSIONS
  8mJ/cm2 UVA irradiation could stimulate the activation of HSF1 and increase HSP70 protein expression. HSF1/HSP70 pathway has a protective effect on UVA-induced HaCaT cells apoptosis and its mechanism is that a large number of HSP70 expression inhibited the activation of JNK.
authors.affiliation: Qingdao University Medical College, Qingdao 266071, China. cookie.wenwen@163.com
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Wang
authors.forename: Chunbo
authors.initials: C
authors.lastname: Wang
authors.forename: Binghua
authors.initials: B
authors.lastname: Li
authors.forename: Yantao
authors.initials: Y
authors.lastname: Han
mesh_terms: D017209:Apoptosis / Q000528:radiation effects*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D018840:HSP70 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D014157:Transcription Factors; D048031:JNK Mitogen-Activated Protein Kinases