title: Neprilysin regulates pulmonary artery smooth muscle cell phenotype through a platelet-derived growth factor receptor-dependent mechanism.
abstract: Reduced neprilysin (NEP), a cell surface metallopeptidase, which cleaves and inactivates proinflammatory and vasoactive peptides, predisposes the lung vasculature to exaggerated remodeling in response to hypoxia. We hypothesize that loss of NEP in pulmonary artery smooth muscle cells results in increased migration and proliferation. Pulmonary artery smooth muscle cells isolated from NEP(-/-) mice exhibited enhanced migration and proliferation in response to serum and platelet-derived growth factor, which was attenuated by NEP replacement. Inhibition of NEP by overexpression of a peptidase dead mutant or knockdown by small interfering RNA in NEP(+/+) cells increased migration and proliferation. Loss of NEP led to an increase in Src kinase activity and phosphorylation of PTEN, resulting in activation of the platelet-derived growth factor receptor (PDGFR). Knockdown of Src kinase with small interfering RNA or inhibition with PP2, a src kinase inhibitor, decreased PDGFR(Y751) phosphorylation and attenuated migration and proliferation in NEP(-/-) smooth muscle cells. NEP substrates, endothelin 1 or fibroblast growth factor 2, increased activation of Src and PDGFR in NEP(+/+) cells, which was decreased by an endothelin A receptor antagonist, neutralizing antibody to fibroblast growth factor 2 and Src inhibitor. Similar to the observations in pulmonary artery smooth muscle cells, levels of phosphorylated PDGFR, Src, and PTEN were elevated in NEP(-/-) lungs. Endothelin A receptor antagonist also attenuated the enhanced responses in NEP(-/-) pulmonary artery smooth muscle cells and lungs. Taken together our results suggest a novel mechanism for the regulation of PDGFR signaling by NEP substrates involving Src and PTEN. Strategies that increase lung NEP activity/expression or target key downstream effectors, like Src, PTEN, or PDGFR, may be of therapeutic benefit in pulmonary vascular disease.
authors: Cardiovascular Pulmonary Research Laboratory, RC-2 Room 8118, University of Colorado Anschutz Medical Campus, 12700 E 19th Ave, RC-2, Aurora, CO 80045, USA. vijaya.karoor@ucdenver.edu
authors: Vijaya
authors: V
authors: Karoor
authors: Masahiko
authors: M
authors: Oka
authors: Sandra J
authors: SJ
authors: Walchak
authors: Louis B
authors: LB
authors: Hersh
authors: York E
authors: YE
authors: Miller
authors: Edward C
authors: EC
authors: Dempsey
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006976:Hypertension, Pulmonary / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D015260:Neprilysin / Q000494:pharmacology*; D010641:Phenotype; D011651:Pulmonary Artery / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D020797:Receptor, Platelet-Derived Growth Factor beta; D015260:Neprilysin
references: EMBO J. 2003 Jul 1;22(13):3346-55
references: 12839996
references: J Biol Chem. 2003 Oct 10;278(41):40057-66
references: 12869565
references: Ann N Y Acad Sci. 1996 Mar 22;780:156-63
references: 8602728
references: Am J Respir Cell Mol Biol. 2010 Apr;42(4):482-90
references: 19520921
references: Am J Physiol Lung Cell Mol Physiol. 2009 Dec;297(6):L1082-90
references: 19801450
references: Circ Res. 2008 May 9;102(9):1036-45
references: 18340011
references: Pulm Circ. 2011 Apr-Jun;1(2):259-68
references: 22034611
references: Biochem Soc Trans. 2003 Jun;31(Pt 3):723-7
references: 12773192
references: Prostate Cancer Prostatic Dis. 2008;11(1):79-87
references: 17563767
references: Expert Opin Investig Drugs. 2012 Jan;21(1):119-34
references: 22074410
references: Nat Med. 1997 Aug;3(8):904-7
references: 9256283
references: Am J Pathol. 2009 Mar;174(3):782-96
references: 19234135
references: Int J Obes (Lond). 2011 Aug;35(8):1031-40
references: 21042321
references: Int J Biochem Cell Biol. 2009 Nov;41(11):2287-94
references: 19464387
references: Am J Respir Crit Care Med. 2011 Feb 1;183(3):330-40
references: 20813891
references: Trends Pharmacol Sci. 2011 Aug;32(8):443-50
references: 21612832
references: Blood. 1996 Dec 1;88(11):4159-65
references: 8943850
references: Am J Physiol. 1993 Feb;264(2 Pt 1):L100-6
references: 8447423
references: J Clin Invest. 2008 May;118(5):1846-57
references: 18382765
references: Acta Pol Pharm. 2011 May-Jun;68(3):307-16
references: 21648184
references: J Am Coll Cardiol. 2009 Jun 30;54(1 Suppl):S10-S19
references: 19555853
references: Proc Natl Acad Sci U S A. 1999 Sep 28;96(20):11653-8
references: 10500232
references: Curr Opin Cell Biol. 1997 Apr;9(2):187-92
references: 9069259
references: Biochim Biophys Acta. 2005 Aug 1;1751(1):52-9
references: 16054017
references: EMBO J. 2000 Oct 16;19(20):5387-95
references: 11032806
references: J Hypertens. 2005 Nov;23(11):2071-82
references: 16208151
references: J Cardiovasc Pharmacol. 2007 Sep;50(3):247-56
references: 17878751
references: Am J Respir Cell Mol Biol. 2005 Nov;33(5):438-46
references: 16002577