Hypoxia increases glyceraldehyde-3-phosphate dehydrogenase transcription in rat alveolar epithelial cells.
Alveolar epithelial type II (ATII) cells are particularly hypoxia-tolerant in vitro. As one of the mechanisms of hypoxia tolerance is the induction of certain proteins, one of which is glyceraldehyde-3-phosphate dehydrogenase (GAPDH), we investigated whether hypoxia modified GAPDH expression in ATII cells. Hypoxia induced a time- and O(2) concentration-dependent accumulation of GAPDH mRNA in cultured rat ATII cells (2- to 3-fold the normoxic value after 18 h in 0% O(2)), an effect completely reversed by reoxygenation. GAPDH mRNA induction was accounted for by an increase in GAPDH gene transcription during hypoxia with no change in mRNA stability. GAPDH protein synthesis increased 3- to 4-fold after 18 h of 0% O(2), while the GAPDH protein steady-state level rose by 75%. GAPDH enzymatic activity in hypoxic cell homogenates increased by 45%. These results indicate that hypoxia induces GAPDH expression in ATII cells through an increase in transcription.
Escoubet
B
B
Department of Physiology, INSERM U 426, Faculté de Médecine Xavier Bichat, Université Paris 7, Paris, 75018, France.
Planès
C
C
Clerici
C
C
D000818:Animals; D015687:Cell Hypoxia / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003035:Cobalt / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology; D011233:Precipitin Tests; D011650:Pulmonary Alveoli / Q000166:cytology / Q000201:enzymology*; D020871:RNA Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
D012333:RNA, Messenger; D003035:Cobalt; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; C018021:cobaltous chloride; D010100:Oxygen