The effects of overexpression of Nurr1 on vulnerability of SK-N-SH cells to neurotoxin 6-OHDA / 中国药理学通报

ABSTRACT

Aim To investigate whether Nurr1 gene,a member of the nuclear receptor superfamily of transcription factors,contributed to 6-OHDA-induced DAergic neurons insults by comparing the effect of 6OHDA on neuroblastoma cells SK-N-SH and SK-N-SH cells overexpressing Nurr1gene(SK-N-SH/Nurr1).Methods The effect of Nurr1 gene on cell proliferation of SK-N-SH cells was investigated,then SK-N-SH and SK-N-SH/Nurr1 cells were exposed to 6-OHDA(5～100 ?mol?L~(-1))for 1～24 h,cells' morphology was observed under phase-contrast microscope.The cells viability was analyzed via MTT assay.Apoptosis was detected using Hoechst33342 staining.Results The Nurr1-overexpressing SK-N-SH cells showed significantly slow growth rate compared with that of SK-N-SH cells.Treatment with 50 ?mol?L~(-1) 6-OHDA changed SK-N-SH-Nurr1 cells' morphology within 1 h,accompanied by retraction of processes,shrinkage of cell body,whereas the morphology of SK-N-SH cells changed after treated with 50?mol?L~(-1) 6-OHDA for 2 h.The result of MTT assay indicated that exposure to 100 ?mol?L~(-1) 6-OHDA for 24 h induced a significant decrease in SK-N-SH/Nurr1 cells survival compared with SK-N-SH cells at various time points with an IC_(50) value of 75 ?mol?L~(-1) and 50 ?mol?L~(-1) respectively in SK-N-SH and SK-N-SH/Nurr1 cells.The evidence that treatment with 75 ?mol?L~(-1) 6-OHDA for 12 h induced typical apoptosis in SK-N-SH/Nurr1 cells was found in morphological features provided by Hoechst33342 staining,including chromatin condensation and nuclear fragmentation,and the percentages of apoptosis in SK-N-SH/Nurr1 cells was about 22%～24%.In contrast,no morphological characteristics of apoptosis in SK-N-SH cells were observed.Conclusions The present study suggests that Nurr1 gene renders SK-N-SH cells more vulnerable to neurotoxic insults. The mechanism of such action is probanly that normal Nurr1 gene function can stimulate apoptotic pathway induced by 6-OHDA,and play a major role in the high sensitivity of DArgic neurons to 6-OHDA insults as a vulnerable factor.