title: Activation of Calpain-2 by Mediators in Pulmonary Vascular Remodeling of Pulmonary Arterial Hypertension.
abstract: Calpain mediates collagen synthesis and cell proliferation and plays an important role in pulmonary vascular remodeling in pulmonary arterial hypertension (PAH). In the present study, we investigated whether and how calpain is activated by PAH mediators in pulmonary artery smooth muscle cells (PASMCs). These data show that smooth muscle-specific knockout of calpain attenuated and knockout of calpastatin potentiated pulmonary vascular remodeling and pulmonary hypertension. Treatment of PASMCs with the PAH mediators platelet-derived growth factor (PDGF), serotonin, H2O2, endothelin-1, and IL-6 caused significant increases in calpain activity, cell proliferation, and collagen-I protein level without changes in protein levels of calpain-1 and -2. The calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA/AM) did not affect calpain activation, but the extracellular signal-regulated kinase (ERK) 1/2 inhibitor PD98059 and knocking down of calpain-2 prevented calpain activation in PAH mediator-treated PASMCs. Mass spectrometry data showed that the phosphorylation of calpain-2 at serine (Ser) 50 was increased and the phosphorylation of calpain-2 at Ser369 was decreased in PDGF-treated PASMCs. The PDGF-induced increase in Ser50 phosphorylation of calpain-2 was prevented by PD98059, whereas dephosphorylation of calpain-2 at Ser369 was blocked by the protein phosphatase 2A inhibitor fostriecin. Furthermore, smooth muscle of pulmonary arteries in PAH animal models and patients with PAH showed higher levels of phospho-Ser50-calpain-2 (P-Ser50) and lower levels of phospho-Ser369-calpain-2 (P-Ser369). These data support that calpain modulates pulmonary vascular remodeling in PAH. PAH mediator-induced activation of calpain is caused by ERK1/2-dependent phosphorylation of calpain-2 at Ser50 and protein phosphatase 2A-dependent dephosphorylation of calpain-2 at Ser369 in pulmonary vascular remodeling of PAH.
authors.affiliation: Departments of 1 Pharmacology and Toxicology.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Kovacs
authors.affiliation: Departments of 1 Pharmacology and Toxicology.
authors.forename: Weihong
authors.initials: W
authors.lastname: Han
authors.affiliation: 2 Vascular Biology Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia.
authors.forename: Ruslan
authors.initials: R
authors.lastname: Rafikov
authors.affiliation: 2 Vascular Biology Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Bagi
authors.affiliation: 3 Max Planck Institute for Heart and Lung Research, Goethe University, Frankfurt, Germany; and.
authors.forename: Stefan
authors.initials: S
authors.lastname: Offermanns
authors.affiliation: 4 Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan.
authors.forename: Takaomi C
authors.initials: TC
authors.lastname: Saido
authors.affiliation: 2 Vascular Biology Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Black
authors.affiliation: Departments of 1 Pharmacology and Toxicology.|5 Medicine, and.|2 Vascular Biology Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia.|6 Research Service, Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia.
authors.forename: Yunchao
authors.initials: Y
authors.lastname: Su
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002154:Calpain / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D006976:Hypertension, Pulmonary / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D000860:Hypoxia / Q000150:complications; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D011651:Pulmonary Artery / Q000187:drug effects / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology; D034622:RNA Interference; D015398:Signal Transduction; D014162:Transfection; D066253:Vascular Remodeling / Q000187:drug effects
chemical_list: D002135:Calcium-Binding Proteins; D020536:Enzyme Activators; D047428:Protein Kinase Inhibitors; C033668:calpastatin; D048049:Extracellular Signal-Regulated MAP Kinases; D054648:Protein Phosphatase 2; D002154:Calpain; C410233:Capns1 protein, mouse; C484806:CAPN1 protein, human; C569870:CAPN2 protein, human; C570925:Capn2 protein, mouse
keywords: H2O2; platelet-derived growth factor; pulmonary hypertension; serotonin; vascular smooth muscle cells