Interferon-gamma induces prolyl hydroxylase (PHD)3 through a STAT1-dependent mechanism in human endothelial cells.
OBJECTIVE
We previously reported that interferons (IFNs) regulate transcription of HIF-1alpha in human endothelial cells (ECs), linking immunity and hypoxia. Prolyl hydroxylases (PHDs) regulate expression of HIF-1alpha in response to hypoxia. We examined whether IFNs affect PHD expression and whether PHDs regulate the EC response to IFNs.


RESULTS
Human cell cultures were treated with various cytokines, and PHD expression was examined using qRT-PCR and immunoblotting. IFNgamma and, to a lesser extent, IFNalpha significantly induced PHD3, but not PHD1 or 2, mRNA, and protein expression selectively in ECs directly via a JAK/STAT1 pathway as demonstrated by pharmacological inhibition, siRNA knockdown, and chromatin immunoprecipitation. Inhibition of PHD activity with dimethyloxallyl glycine or desferroxamine reduced IFNg-dependent responses in these same cells.


CONCLUSIONS
IFNgamma induces PHD3 through a JAK/STAT1-dependent mechanism in human ECs. Induction is independent of HIF-1alpha and may contribute to expression of IFNgamma-dependent genes.
Gerber
Scott A
SA
Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520-8089 , USA.
Yatsula
Bogdan
B
Maier
Cheryl L
CL
Sadler
Timothy J
TJ
Whittaker
Laurence W
LW
Pober
Jordan S
JS
D000600:Amino Acids, Dicarboxylic / Q000494:pharmacology; D015687:Cell Hypoxia; D002478:Cells, Cultured; D003676:Deferoxamine / Q000494:pharmacology; D049308:Dioxygenases / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017781:Genes, Immediate-Early; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D016898:Interferon-alpha / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism*; D053612:Janus Kinases / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014158:Transcription, Genetic
D000600:Amino Acids, Dicarboxylic; D004791:Enzyme Inhibitors; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016898:Interferon-alpha; D012333:RNA, Messenger; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D007371:Interferon-gamma; D049308:Dioxygenases; C488894:EGLN3 protein, human; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D053612:Janus Kinases; D003676:Deferoxamine; C040947:oxalylglycine