Down-modulation of Bis sensitizes cell death in C6 glioma cells induced by oxygen-glucose deprivation.
Bcl-2 interacting cell death suppressor (Bis), also known as Bag3, has been implicated in anti-stress and anti-apoptotic pathways. In a previous study, we observed a significant induction of Bis in reactive astrocytes of the rat hippocampus after transient forebrain ischemia. To investigate the significance of this induction in ischemic injury, the expression of Bis was reduced with siRNA in C6 glioma cells and exposed to oxygen-glucose deprivation (OGD) conditions. Bis knock-down resulted in an increase in the cell death rate of the C6 cells after OGD, accompanied by accumulation of reactive oxygen species. Among the cellular antioxidants, the induction of superoxide dismutase (SOD) activity was significantly interfered within the cells treated with bis siRNA treated cells (bis-kd C6). A Western blot assay revealed that SOD1 expression gradually increased in control cells, which was not observed in bis-kd cells upon OGD treatment. A quantitative analysis of Sod1 and Sod2 transcripts indicated that the induction of Sod1 was more evidently suppressed by the reduction of Bis. As a transcription factor candidate for the Sod1 gene, the activity of NF-kappaB was determined the nuclear translocation of p65, showing that the activation of NF-kappaB was attenuated in bis-kd C6. Supporting this, an overexpression of Bis augments the activation of NF-kappaB and Sod1 mRNA with an increased cell survival under OGD conditions. These results suggest that one of physiological significances of Bis induction in reactive astrocytes after ischemia in vivo is to protect glial cells from oxidative stress, probably via the induction of SOD1, which is related to the activation of NF-kappaB.
Jung
Seung Eun
SE
Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Kim
Yong Kwan
YK
Youn
Dong-Ye
DY
Lim
Mi-Hyun
MH
Ko
Jeong Heon
JH
Ahn
Young Soo
YS
Lee
Jeong-Hwa
JH
D000111:Acetylcysteine / Q000494:pharmacology; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D016166:Free Radical Scavengers / Q000494:pharmacology; D005910:Glioma / Q000473:pathology; D005947:Glucose / Q000172:deficiency*; D000860:Hypoxia; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C498807:BAG3 protein, rat; D016166:Free Radical Scavengers; D016328:NF-kappa B; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D013482:Superoxide Dismutase; D005947:Glucose; D000111:Acetylcysteine