title: ATP stimulates MMP-2 release from human aortic smooth muscle cells via JNK signaling pathway.
abstract: Aortic smooth muscle cell release of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) has been implicated in aortic aneurysm pathogenesis, but proximal modulation of release is poorly understood. Extracellular nucleotides regulate vascular smooth muscle cell metabolism in response to physiochemical stresses, but nucleotide modulation of MMP and/or TIMP release has not been reported. We hypothesized that nucleotides modulate MMP-2 and TIMP-2 release from human aortic smooth muscle cells (HASMCs) via distinct purinergic receptors and signaling pathways. We exposed HASMCs to exogenous ATP and other nucleotides with and without interleukin-1beta (IL-1beta). HASMCs were pretreated in some experiments with apyrase, which degrades ATP, and inhibitors of ERK1/2, JNK, and p38 MAPK. MMP-2 and TIMP-2 released into supernatant were assessed using ELISA and Western blotting. ATP, adenosine, and UTP significantly stimulated MMP-2 release in the presence of IL-1beta (300 nM ATP: 181 +/- 22%, P = 0.003; 30 microm adenosine: 244 +/- 150%, P = 0.001; and 200 microm UTP: 153 +/- 40%, P = 0.015; vs. 100% constitutive). ATP also stimulated MMP-2 release in the absence of IL-1beta (100 microm ATP: 148 +/- 38% vs. 100% constitutive). Apyrase significantly reduced ATP-stimulated MMP-2 release (apyrase + 500 nM ATP: 59 +/- 3% vs. 124 +/- 7% with 500 nM ATP). Rank-order agonist potency for MMP-2 release was consistent with ATP activation of PAY and PAY receptors. ATP induced phosphorylation of intracellular JNK, and inhibition of the JNK pathway blocked ATP-stimulated MMP-2 release, indicating signaling via this pathway. Nucleotides are thus novel stimulants of MMP-2 release from HASMCs and may provide a mechanistic link between physiochemical stress in the aorta and aneurysms, especially in the context of inflammation.
authors.affiliation: Department of Surgery, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7228, USA.
authors.forename: William P
authors.initials: WP
authors.lastname: Robinson
authors.forename: Christelle D
authors.initials: CD
authors.lastname: Douillet
authors.forename: Peter M
authors.initials: PM
authors.lastname: Milano
authors.forename: Richard C
authors.initials: RC
authors.lastname: Boucher
authors.forename: Cam
authors.initials: C
authors.lastname: Patterson
authors.forename: Preston B
authors.initials: PB
authors.lastname: Rich
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D001011:Aorta / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007375:Interleukin-1 / Q000008:administration & dosage*; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*
chemical_list: D007375:Interleukin-1; D000255:Adenosine Triphosphate; D048670:MAP Kinase Kinase 4; D020778:Matrix Metalloproteinase 2