Central role of Sp1-regulated CD39 in hypoxia/ischemia protection.
Hypoxia is common to several inflammatory diseases, where multiple cell types release adenine-nucleotides (particularly adenosine triphosphate/adenosine diphosphate). Adenosine triphosphate/adenosine diphosphate is metabolized to adenosine through a 2-step enzymatic reaction initiated by CD39 (ectonucleoside-triphosphate-diphosphohydrolase-1). Thus, extracellular adenosine becomes available to regulate multiple inflammatory endpoints. Here, we hypothesized that hypoxia transcriptionally up-regulates CD39 expression. Initial studies revealed hypoxia-dependent increases in CD39 mRNA and immunoreactivity on endothelia. Examination of the human CD39 gene promoter identified a region important in hypoxia inducibility. Multiple levels of analysis, including site-directed mutagenesis, chromatin immunoprecipitation, and inhibition by antisense, revealed a critical role for transcription-factor Sp1 in hypoxia-induction of CD39. Using a combination of cd39(-/-) mice and Sp1 small interfering RNA in in vivo cardiac ischemia models revealed Sp1-mediated induction of cardiac CD39 during myocardial ischemia. In summary, these results identify a novel Sp1-dependent regulatory pathway for CD39 and indicate the likelihood that CD39 is central to protective responses to hypoxia/ischemia.
Eltzschig
Holger K
HK
Department of Anesthesiology and Perioperative Medicine, University of Colorado Health Sciences Center, Denver, CO, USA. holger.eltzschig@uchsc.edu
Köhler
David
D
Eckle
Tobias
T
Kong
Tianqing
T
Robson
Simon C
SC
Colgan
Sean P
SP
D000818:Animals; D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism*; D001081:Apyrase / Q000235:genetics* / Q000378:metabolism*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016297:Mutagenesis, Site-Directed; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D011401:Promoter Regions, Genetic / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering; D016329:Sp1 Transcription Factor / Q000378:metabolism*
D015703:Antigens, CD; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016329:Sp1 Transcription Factor; D001081:Apyrase; C067869:CD39 antigen