title: Histone deacetylation contributes to low extracellular superoxide dismutase expression in human idiopathic pulmonary arterial hypertension.
abstract: Epigenetic mechanisms, including DNA methylation and histone acetylation, regulate gene expression in idiopathic pulmonary arterial hypertension (IPAH). These mechanisms can modulate expression of extracellular superoxide dismutase (SOD3 or EC-SOD), a key vascular antioxidant enzyme, and loss of vascular SOD3 worsens outcomes in animal models of pulmonary arterial hypertension. We hypothesized that SOD3 gene expression is decreased in patients with IPAH due to aberrant DNA methylation and/or histone deacetylation. We used lung tissue and pulmonary artery smooth muscle cells (PASMC) from subjects with IPAH at transplantation and from failed donors (FD). Lung SOD3 mRNA expression and activity was decreased in IPAH vs. FD. In contrast, mitochondrial SOD (Mn-SOD or SOD2) protein expression was unchanged and intracellular SOD activity was unchanged. Using bisulfite sequencing in genomic lung or PASMC DNA, we found the methylation status of the SOD3 promoter was similar between FD and IPAH. Furthermore, treatment with 5-aza-2'-deoxycytidine did not increase PASMC SOD3 mRNA, suggesting DNA methylation was not responsible for PASMC SOD3 expression. Though total histone deacetylase (HDAC) activity, histone acetyltransferase (HAT) activity, acetylated histones, and acetylated SP1 were similar between IPAH and FD, treatment with two selective class I HDAC inhibitors increased SOD3 only in IPAH PASMC. Class I HDAC3 siRNA also increased SOD3 expression. Trichostatin A, a pan-HDAC inhibitor, decreased proliferation in IPAH, but not in FD PASMC. These data indicate that histone deacetylation, specifically via class I HDAC3, decreases SOD3 expression in PASMC and HDAC inhibitors may protect IPAH in part by increasing PASMC SOD3 expression.
authors.affiliation: Department of Pediatrics, University of Colorado Anschutz Medical Center, Aurora, Colorado; Cardiovascular Pulmonary Research, University of Colorado Anschutz Medical Center, Aurora, Colorado; eva.grayck@ucdenver.edu.
authors.forename: Eva
authors.initials: E
authors.lastname: Nozik-Grayck
authors.affiliation: Department of Pediatrics, University of Colorado Anschutz Medical Center, Aurora, Colorado; Cardiovascular Pulmonary Research, University of Colorado Anschutz Medical Center, Aurora, Colorado;
authors.forename: Crystal
authors.initials: C
authors.lastname: Woods
authors.affiliation: Department of Medicine, Indiana University, Indianapolis, Indiana; and.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Stearman
authors.affiliation: Department of Pediatrics, University of Colorado Anschutz Medical Center, Aurora, Colorado;
authors.forename: Sujatha
authors.initials: S
authors.lastname: Venkataraman
authors.affiliation: Department of Medicine, University of Colorado Anschutz Medical Center, Aurora, Colorado;
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Ferguson
authors.affiliation: Department of Pediatrics, University of Colorado Anschutz Medical Center, Aurora, Colorado; Cardiovascular Pulmonary Research, University of Colorado Anschutz Medical Center, Aurora, Colorado;
authors.forename: Kalin
authors.initials: K
authors.lastname: Swain
authors.affiliation: Department of Medicine, National Jewish Hospital, Denver, Colorado;
authors.forename: Russell P
authors.initials: RP
authors.lastname: Bowler
authors.affiliation: Department of Medicine, Indiana University, Indianapolis, Indiana; and.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Geraci
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania;
authors.forename: Kaori
authors.initials: K
authors.lastname: Ihida-Stansbury
authors.affiliation: Department of Pediatrics, University of Colorado Anschutz Medical Center, Aurora, Colorado; Cardiovascular Pulmonary Research, University of Colorado Anschutz Medical Center, Aurora, Colorado; Department of Medicine, University of Colorado Anschutz Medical Center, Aurora, Colorado;
authors.forename: Kurt R
authors.initials: KR
authors.lastname: Stenmark
authors.affiliation: Department of Medicine, University of Colorado Anschutz Medical Center, Aurora, Colorado;
authors.forename: Timothy A
authors.initials: TA
authors.lastname: McKinsey
authors.affiliation: Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
authors.forename: Frederick E
authors.initials: FE
authors.lastname: Domann
mesh_terms: D000107:Acetylation; D000328:Adult; D000818:Animals; D002478:Cells, Cultured; D004794:Enzyme Repression; D005260:Female; D015870:Gene Expression; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006657:Histones / Q000378:metabolism*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000201:enzymology; D011401:Promoter Regions, Genetic; D011499:Protein Processing, Post-Translational; D051381:Rats; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
chemical_list: D056572:Histone Deacetylase Inhibitors; D006657:Histones; C441642:SOD3 protein, human; D013482:Superoxide Dismutase
keywords: DNA methylation; extracellular superoxide dismutase; histone deacetylation; idiopathic pulmonary arterial hypertension