Regulation of xanthine dehydrogenase and xanthine oxidase activity and gene expression in cultured rat pulmonary endothelial cells.
The central importance of xanthine dehydrogenase (XDH) and xanthine oxidase (XO) in the pathobiochemistry of a number of clinical disorders underscores the need for a comprehensive understanding of the regulation of their expression. This study was undertaken to examine the effects of cytokines on XDH/XO activity and gene expression in pulmonary endothelial cells. The results indicate that IFN-gamma is a potent inducer of XDH/XO activity in rat lung endothelial cells derived from both the microvasculature (LMVC) and the pulmonary artery. In contrast, interferon-alpha/beta, tumor necrosis factor-alpha, interleukin-1 or -6, lipopolysaccharide and phorbol myristate acetate have no demonstrable effect. The increase in XDH/XO activity requires new protein synthesis. By Northern analysis, IFN-gamma markedly increases the level of the 5.0-kb XDH/XO mRNA in LMVC. The increase is due, in part, to increased transcription rate of the XDH/XO gene. Transcriptional activation does not require new protein synthesis. The physiologic relevance of these observations was evaluated by administering IFN-gamma to rats. Intraperitoneal administration leads to an increased XDH/XO activity and XDH/XO mRNA level in rat lungs. In sum, IFN-gamma is a potent and biologically relevant inducer of XDH/XO expression; the major site of upregulation occurs at the transcriptional level.
Department of Medicine, University of Utah School of Medicine, Salt Lake City.
G P
GP
Dupont
T P
TP
Huecksteadt
B C
BC
Marshall
U S
US
Ryan
J R
JR
Michael
J R
JR
Hoidal
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007249:Inflammation / Q000378:metabolism; D007372:Interferons / Q000494:pharmacology; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014968:Xanthine Dehydrogenase / Q000235:genetics*; D014969:Xanthine Oxidase / Q000235:genetics*
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007372:Interferons; D003513:Cycloheximide; D014968:Xanthine Dehydrogenase; D014969:Xanthine Oxidase