[Effect of heat shock response on the cleavage of nucleolin induced by oxidative stress].
OBJECTIVE
To observe the cleavage of nucleolin (C23) during apoptosis induced by oxidative stress and to clarify the effect of heat shock response (HSR) on the cleavage of nucleolin and its possible molecular mechanism.


METHODS
We added 0.5 mmol/L peroxide hydrogen (H2O2 ) into cultured cells to mimic oxidative stress. Apoptosis and cleavage of C23 were detected using caspase-3 colorimetric assay and Western blotting respectively. HSR was performed to observe the effect of HSR on cleavage of C23 induced by oxidative stress, and over-expressions of HSP70 and HSP25 were detected by Western blotting.


RESULTS
Activity of caspase-3 increased significantly after 2 hours of 0.5 mmol/L H2O2 treatment, and reached the peak after 12 hours. The cleavage of C23 appeared 30 minutes to 1 hour after the treatment of H2O2 as indicated by a cleaved fragmentation of 80 kD, which was significantly inhibited by HSR. Moreover, HSR could induce HSP70 and HSP25 over-expressions.


CONCLUSIONS
Oxidative stress can induce the activation of caspase-3, cleavage of C23, and apoptosis. HSR can significantly inhibit the cleavage of C23 induced by oxidative stress, which is related to the over-expressions of HSP70, HSP25, and other stress proteins.
Wang
Kang-kai
KK
Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha 410078, China.
Jiang
Lei
L
Yi
Yu-xin
YX
Liu
Ke
K
E
Shun-Mei
SM
Tang
Dao-lin
DL
Wang
Jian-she
JS
Shi
Yong-zhong
YZ
Wang
Qiu-peng
QP
Xiao
Xian-zhong
XZ
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide; D006979:Hyperthermia, Induced; D008297:Male; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism; D018384:Oxidative Stress; D010750:Phosphoproteins / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D000097796:Nucleolin
D053148:Caspase 3; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D006861:Hydrogen Peroxide; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D000097796:Nucleolin