Regulation of soluble guanylyl cyclase-alpha1 expression in chronic hypoxia-induced pulmonary hypertension: role of NFATc3 and HuR.
The nitric oxide/soluble guanylyl cyclase (sGC) signal transduction pathway plays an important role in smooth muscle relaxation and phenotypic regulation. However, the transcriptional regulation of sGC gene expression is largely unknown. It has been shown that sGC expression increases in pulmonary arteries from chronic hypoxia-induced pulmonary hypertensive animals. Since the transcription factor NFATc3 is required for the upregulation of the smooth muscle hypertrophic/differentiation marker alpha-actin in pulmonary artery smooth muscle cells from chronically hypoxic mice, we hypothesized that NFATc3 is required for the regulation of sGC-alpha1 expression during chronic hypoxia. Exposure to chronic hypoxia for 2 days induced a decrease in sGC-alpha1 expression in mouse pulmonary arteries. This reduction was independent of NFATc3 but mediated by nuclear accumulation of the mRNA-stabilizing protein human antigen R (HuR). Consistent with our hypothesis, chronic hypoxia (21 days) upregulated pulmonary artery sGC-alpha1 expression, bringing it back to the level of the normoxic controls. This response was prevented in NFATc3 knockout and cyclosporin (calcineurin/NFATc inhibitor)-treated mice. Furthermore, we identified effective binding sites for NFATc in the mouse sGC-alpha1 promoter. Activation of NFATc3 increased sGC-alpha1 promoter activity in human embryonic derived kidney cells, rat aortic-derived smooth muscle cells, and human pulmonary artery smooth muscle cells. Our results suggest that NFATc3 and HuR are important regulators of sGC-alpha1 expression in pulmonary vascular smooth muscle cells during chronic hypoxia-induced pulmonary hypertension.
de Frutos
Sergio
S
Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico 87131, USA.
Nitta
Carlos H
CH
Caldwell
Elizabeth
E
Friedman
Jessica
J
González Bosc
Laura V
LV
D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D019703:Calcineurin / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002908:Chronic Disease; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D017353:Gene Deletion; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000201:enzymology* / Q000209:etiology*; D000860:Hypoxia / Q000150:complications* / Q000201:enzymology*; D015759:Ionomycin / Q000494:pharmacology; D008297:Male; D051379:Mice; D050778:NFATC Transcription Factors / Q000378:metabolism*; D017354:Point Mutation / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D020033:Protein Isoforms; D011651:Pulmonary Artery / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D000071756:Soluble Guanylyl Cyclase; D014162:Transfection
D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D050778:NFATC Transcription Factors; D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; C445503:transcription factor NF-AT c3; D015759:Ionomycin; D019703:Calcineurin; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase