Cross-talk between p(38)MAPK and G iα in regulating cPLA 2 activity by ET-1 in pulmonary smooth muscle cells

Mol Cell Biochem. 2015 Feb;400(1-2):107-23. doi: 10.1007/s11010-014-2267-0. Epub 2014 Nov 16.

Abstract

Endothelin-1 (ET-1) is known as the most potent vasoconstrictor yet described. Infusion of ET-1 into isolated rabbit lung has been shown to cause pulmonary vasoconstriction with the involvement of arachidonic acid metabolites. Given the potency of arachidonic acid metabolites, the activity of phospholipase A2 must be tightly regulated. Herein, we determined the mechanisms by which ET-1 stimulates cPLA2 activity during ET-1 stimulation of bovine pulmonary artery smooth muscle cells. We demonstrated that (i) treatment of bovine pulmonary artery smooth muscle cells with ET-1 stimulates cPLA2 activity in the cell membrane; (ii) ET-1 caused increase in O 2 (·-) production occurs via NADPH oxidase-dependent mechanism; (iii) ET-1-stimulated NADPH oxidase activity is markedly prevented upon pretreatment with PKC-ζ inhibitor, indicating that PKC-ζ plays a prominent role in this scenario; (iv) ET-1-induced NADPH oxidase-derived O 2 (·-) stimulates an aprotinin sensitive protease activity due to prominent increase in [Ca(2+)]i; (v) the aprotinin sensitive protease plays a pivotal role in activating PKC-α, which in turn phosphorylates p(38)MAPK and subsequently Giα leading to the activation of cPLA2. Taken together, we suggest that cross-talk between p(38)MAPK and Giα with the involvement of PKC-ζ, NADPH oxidase-derived O 2 (·-) , [Ca(2+)]i, aprotinin-sensitive protease and PKC-α play a pivotal role for full activation of cPLA2 during ET-1 stimulation of pulmonary artery smooth muscle cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arachidonic Acid / metabolism
  • Cattle
  • Cell Membrane
  • Endothelin-1 / genetics
  • Endothelin-1 / metabolism*
  • GTP-Binding Proteins / metabolism*
  • Myocytes, Smooth Muscle / metabolism
  • NADPH Oxidases / metabolism
  • Phospholipases A2 / biosynthesis
  • Phospholipases A2 / metabolism*
  • Pulmonary Artery / metabolism
  • Vasoconstriction / genetics
  • p38 Mitogen-Activated Protein Kinases / biosynthesis
  • p38 Mitogen-Activated Protein Kinases / metabolism*

Substances

  • Endothelin-1
  • Arachidonic Acid
  • NADPH Oxidases
  • p38 Mitogen-Activated Protein Kinases
  • Phospholipases A2
  • GTP-Binding Proteins