Involvement of Ca²⁺/calmodulin-dependent protein kinase II in endothelial NO production and endothelium-dependent relaxation

Abstract

Nitric oxide (NO) is synthesized from l-arginine by the Ca(2+)/calmodulin-sensitive endothelial NO synthase (NOS) isoform (eNOS). The present study assesses the role of Ca(2+)/calmodulin-dependent protein kinase II (CaMK II) in endothelium-dependent relaxation and NO synthesis. The effects of three CaMK II inhibitors were investigated in endothelium-intact aortic rings of normotensive rats. NO synthesis was assessed by a NO sensor and chemiluminescence in culture medium of cultured porcine aortic endothelial cells stimulated with the Ca(2+) ionophore A23187 and thapsigargin. Rat aortic endothelial NOS activity was measured by the conversion of l-[(3)H]arginine to l-[(3)H]citrulline. Three CaMK II inhibitors, polypeptide 281-302, KN-93, and lavendustin C, attenuated the endothelium-dependent relaxation of endothelium-intact rat aortic rings in response to acetylcholine, A23187, and thapsigargin. None of the CaMK II inhibitors affected the relaxation induced by NO donors. In a porcine aortic endothelial cell line, KN-93 decreased NO synthesis and caused a rightward shift of the concentration-response curves to A23187 and thapsigargin. In rat aortic endothelial cells, KN-93 significantly decreased bradykinin-induced eNOS activity. These results suggest that CaMK II was involved in NO synthesis as a result of Ca(2+)-dependent activation of eNOS.

Impact of vitamin D supplementation on endothelial and inflammatory markers in adults: A systematic review

“…This increase would in turn lead to an increase in the intestinal absorption of calcium, which may result in increased intracellular calcium, which would in turn stimulate the production of NO, a potent vasodilator purported to have protective effects on the endothelium. This is an indirect route by which vitamin D increases nitric oxide availability [46]. renin suppression, independent of calcium metabolism [48].…”

AKT Participates in Endothelial Dysfunction in Hypertension

“…Several kinases share the ability to phosphorylate this site, including protein kinase A, protein kinase C, CAMKII and the serine/threonine kinase AKT. [7][8][9][10][11] This latter seems to possess the unique feature to be activated by many independent signal transduction pathways. In fact, AKT kinase is activated primarily in response to stimulation of transmembrane receptors with intrinsic tyrosine kinase activity or indirectly coupled to tyrosine kinases or to 7-transmembrane G protein-coupled receptors.…”

Protein kinase D activity controls endothelial nitric oxide synthesis

“…Hence, the activation observed upon eNOS phosphorylation on Ser1179 very likely reflects the displacement of this a-helix and the concomitant increased electron transfer within the reductase domain. In addition, eNOS Ser1179 phosphorylation (very frequently accompanied by coordinated dephosphorylation of Thr495) diminishes the Ca 2+ sensitivity of the enzyme (Fulton et al, 1999;McCabe et al, 2000;Schneider et al, 2003).…”

“…Upon the application of fluid shear stress (Dimmeler et al, 1999;Gallis et al, 1999), acute mechanical stretch (Hu et al, 2013) or UV light (Park et al, 2011), eNOS becomes rapidly phosphorylated on Ser1179. Likewise, treatment of endothelial monolayers with VEGF (Fulton et al, 1999;Michell et al, 1999), insulin (Salt et al, 2003), estrogens (Haynes et al, 2000), endothelin-1 (Liu et al, 2003) or bradykinin (Fleming et al, 2001;Schneider et al, 2003) leads to eNOS Ser1179 phosphorylation. To date, it has been shown that at least six protein kinases [Akt, AMPK, PKA, cGK-I/PKG, Chk1 and Ca 2+ / calmodulin-dependent protein kinase II (CaMKII)] are involved in Fig.…”