Induction of mRNAs and proteins for Na/K ATPase alpha1 and beta1 subunits following hypoxia/reoxygenation in astrocytes.
Characteristics of the cellular response to oxygen deprivation and subsequent reoxygenation (hypoxia/reoxygenation) include redirection of energy metabolism, increased glucose utilization and expression of oxygen-regulated proteins. Inhibition of protein synthesis during early reoxygenation period prevented effective astrocyte adaptation to hypoxia/reoxygenation, resulting in eventual cell death. To elucidate the role of astrocytes in the central nervous system in response to hypoxia/reoxygenation, we analyzed the cDNA library derived from the cultured rat astrocytes subjected to 24 h of hypoxia followed by reoxygenation by differential display, and isolated a cDNA corresponding to Na/K ATPase alpha1 subunit. The expression of Na/K ATPase alpha1 subunit mRNA as well as beta1subunit mRNA was transiently increased after reoxygenation, whereas hypoxia itself did not induce any gene expression change. Na/K ATPase alpha1 subunit protein was transiently increased, whereas the protein expression for Na/K ATPase beta1 subunit showed sustained induction after reoxygenation. Overexpression of beta1 subunit in HEK 293 cells subjected to hypoxia/reoxygenation promoted survival of the cells. These findings suggest that Na/K ATPases may contribute to maintain the cellular environment of astrocytes subjected to hypoxia/reoxygenation.
Kasai
Kosuke
K
Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Yamashita
Toshihide
T
Yamaguchi
Atsushi
A
Yoshiya
Kazuhisa
K
Kawakita
Akihiro
A
Tanaka
Hiroshi
H
Sugimoto
Hisashi
H
Tohyama
Masaya
M
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000201:enzymology*; D015687:Cell Hypoxia / Q000502:physiology; D002470:Cell Survival; D002478:Cells, Cultured; D015971:Gene Expression Regulation, Enzymologic; D010100:Oxygen / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics* / Q000378:metabolism*
D012333:RNA, Messenger; D000254:Sodium-Potassium-Exchanging ATPase; D010100:Oxygen