title: A role for platelet-derived growth factor beta-receptor in a newborn rat model of endothelin-mediated pulmonary vascular remodeling.
abstract: Newborn rats exposed to 60% O2 for 14 days develop endothelin (ET)-1-dependent pulmonary hypertension with vascular remodeling, characterized by increased smooth muscle cell (SMC) proliferation and medial thickening of pulmonary resistance arteries. Using immunohistochemistry and Western blot analyses, we examined the effect of exposure to 60% O2 on expression in the lung of receptors for the platelet-derived growth factors (PDGF), which are implicated in the pathogenesis of arterial smooth muscle hyperplasia. We observed a marked O2-induced upregulation of PDGF-alpha and -beta receptors (PDGF-alphaR and -betaR) on arterial smooth muscle. This led us to examine pulmonary vascular PDGF receptor expression in 60% O2-exposed rats given SB-217242, a combined ET receptor antagonist, which we found prevented the O2-induced upregulation of PDGF-betaR, but not PDGF-alphaR, on arterial smooth muscle. PDGF-BB, a major PDGF-betaR ligand, was found to be a potent in vitro inducer of hyperplasia and DNA synthesis in cultured pulmonary artery SMC from infant rats. A critical role for PDGF-betaR ligands in arterial SMC proliferation was confirmed in vivo using a truncated soluble PDGF-betaR intervention, which attenuated SMC proliferation induced by exposure to 60% O2. Collectively, these data are consistent with a major role for PDGF-betaR-mediated SMC proliferation, acting downstream of increased ET-1 in a newborn rat model of 60% O2-induced pulmonary hypertension.
authors.affiliation: Clinical Integrative Biology, Sunnybrook & Women's Research Institute, Toronto, Ontario, Canada. robert.jankov@sw.ca
authors.forename: Robert P
authors.initials: RP
authors.lastname: Jankov
authors.forename: Crystal
authors.initials: C
authors.lastname: Kantores
authors.forename: Rosetta
authors.initials: R
authors.lastname: Belcastro
authors.forename: Soojin
authors.initials: S
authors.lastname: Yi
authors.forename: Ross A
authors.initials: RA
authors.lastname: Ridsdale
authors.forename: Martin
authors.initials: M
authors.lastname: Post
authors.forename: A Keith
authors.initials: AK
authors.lastname: Tanswell
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000077214:Becaplermin; D002264:Carboxylic Acids / Q000494:pharmacology; D049109:Cell Proliferation; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology*; D005260:Female; D006965:Hyperplasia; D006976:Hypertension, Pulmonary / Q000209:etiology; D007189:Indans / Q000494:pharmacology; D008024:Ligands; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000473:pathology*; D010100:Oxygen / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D011247:Pregnancy; D020574:Proto-Oncogene Proteins c-sis; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism*; D017466:Receptors, Endothelin / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D002264:Carboxylic Acids; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D007189:Indans; D008024:Ligands; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D017466:Receptors, Endothelin; D000077214:Becaplermin; D020796:Receptor, Platelet-Derived Growth Factor alpha; D020797:Receptor, Platelet-Derived Growth Factor beta; C098288:enrasentan; D010100:Oxygen