Abstract 14742: Expression of SMURF1 is Increased in Patients With Pulmonary Arterial Hypertension and SiRNA Inhibition of SMURF1 Reduces Pulmonary Artery Smooth Muscle Cell Proliferation

• Published in: Circulation (New York, N.Y.) Vol. 138; no. Suppl_1 Suppl 1; p. A14742
• Main Authors: Rothman, Alex M, West, Laura, Srivastava, Salil, Quigley, Catherine, Southwood, Mark, Lawrie, Allan, Francis, Sheila, Morrell, Nick, Rowlands, David
• Format: Journal Article
• Language: English
• Published: by the American College of Cardiology Foundation and the American Heart Association, Inc 06-11-2018
• ISSN: 0009-7322; 1524-4539

RationaleMutation of Bone Morphogenetic Protein (BMP) Receptor II, and reduced downstream signaling, predisposes to pulmonary vascular remodeling and the development of pulmonary arterial hypertension (PAH). Augmentation of signaling in this pathway may reduce the proliferation of key vascular cells and provide therapeutic benefit. SMURF1 is an E3 ligase that is increased in patients with PAH. SMURF1 negatively regulates BMP signaling and global knock-out protects from the development of sugen hypoxia induced PAH.HypothesisSMURF1 expression will be increased in the pulmonary vasculature of patients with PAH and inhibition of SMURF1 will alter pulmonary artery cell phenotype.Methods and ResultsFormalin-fixed samples from 15 control and 18 patients with PAH were dual-stained for endothelial (von Willebrand factor-brown) and smooth muscle (alpha smooth muscle actin-pink) cell markers and sequential slices stained for SMURF1 (brown) using standard techniques. SMURF1 expression was prominent within the media of the pulmonary arteries of patients with heritable, idiopathic, connective tissue disease associated, and congenital heart disease associated PAH (A). Expression of SMURF1 was determined by Western blot in primary pulmonary artery smooth muscle cells (PASMC) from 9 control and 8 patients with PAH. Expression of SMURF1 was increased in patients with heritable and idiopathic PAH (B). PASMC were cultured in 2.5% FBS with 10 ng/mL Bone Morphogenetic Protein 4 and proliferation determined by well confluence and nuclear stain following transfection with control and SMURF1 siRNA. SMURF1 siRNA reduced proliferation at 72 hours (C, n=6, two-way ANOVA, p<0.05).ConclusionsExpression of SMURF1 is predominant within the medial vascular layer of pulmonary arteries in patients with PAH. Expression of SMURF1 in PASMC is increased in patients with PAH when compared to controls and siRNA inhibition of SMURF1 suppresses PASMC proliferation.