Roles of calcium and kinases in regulation of thrombin-stimulated preproendothelin-1 transcription

Abstract

The release of the vasoactive peptide endothelin-1 (ET-1) is Ca2+ dependent after thrombin stimulation; however, little is known about the pathways involved. We studied the importance of Ca(2+)-dependent signal transduction pathways on preproET-1 mRNA induction in human endothelial cells. Thrombin-mediated preproET-1 mRNA induction was inhibited after clamping of cytosolic free CA2+ concentration ([Ca2+]i) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Chelation of extracellular Ca2+ with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid also had a significant inhibitory effect on the induction of preproET-1 mRNA. The Ca2+ ionophore A23187 induced constitutive as well as thrombin-stimulated preproET-1 mRNA expression. Mobilization of Ca2+ stores into the cytosol by inhibition of endoplasmic reticulum Ca(2+)-adenosinetriphosphatase with thapsigargin was effective also in inducing preproET-1 mRNA. Calmodulin antagonists W-7 and calmidazolium, as well as Ca2+/calmodulin-dependent kinase II inhibitor KN-62, significantly reduced thrombin-induced preproET-1 mRNA. Inhibition by cyclosporin A of the Ca(2+)-calmodulin-dependent phosphatase calcineurin potentiated constitutive preproET-1 mRNA. These data suggest that, in human endothelial cells, thrombin-mediated preproET-1 gene induction is regulated by a stimulatory Ca2+/calmodulin kinase II-dependent pathway.

Calcium regulation of endothelin-1 synthesis in rat inner medullary collecting duct

“…In human umbilical vein endothelial cells (HUVEC), thrombin-induced increases in ET-1 mRNA were inhibited by BAPTA, EDTA, Cells were incubated with inhibitor for 4 h, followed by addition of 5 g/ml actinomycin D and determination of mRNA levels over the following 2 h. Data were normalized to snRNP content; snRNP content was unaffected by inhibitor treatment and did not decrease over the 2-h time period following addition of actinomycin D. Arrows indicate time at which 50% of ET-1 mRNA remained; n ϭ 3 each data point. W7, or KN-62, while A23187 increased basal and thrombinstimulated ET-1 mRNA levels (21). In contrast, another group found that ionomycin and A23187 decreased ET-1 production by HUVEC (23).…”

Na +/Ca2+ exchangers and Orai channels jointly refill endoplasmic reticulum (ER) Ca2+ via ER nanojunctions in vascular endothelial cells

“…Activation of non-excitable cells, like endothelial cells (EC), by receptor agonists typically provokes an increase in inositol 1,4,5-trisphosphate (IP 3 ) and consequent endoplasmic reticulum (ER) Ca 2+ release via IP 3 receptors (IP 3 R). The subsequent [Ca 2+ ] i elevation is a preamble underpinning basic EC function like nitric oxide (NO) synthesis by the endothelial NO synthase and endothelin-1 production [ 19 , 32 , 38 , 47 ]. While store-operated Ca 2+ entry (SOCE) is generally considered the main (if not sole) mechanism responsible for cytosolic Ca 2+ resetting and ER Ca 2+ refilling following stimulation [ 2 , 30 ], and evidence exists for a role of mitochondria in ER Ca 2+ regulation [ 30 , 31 ], there is reason to consider that Na + / Ca 2+ exchange (NCX) may also play an important role in this process.…”

The interdependence of endothelin-1 and calcium: a review

“…Although multiple cell types synthesize ET-1, the predominant sources of ET-1 are vascular endothelial cells [44]. Molecules that increase endothelial cell [Ca +2 ] i augment expression of preproendothelin-1 (ppET-1) mRNA via a calcium/calmodulin/calmodulin kinase (Ca 2+ /CaM/CaM-K) pathway [45, 46]. The physiological responses elicited by ET-1 can be both calcium-dependent and calcium-independent [16, 47, 48].…”