首页|AMPK upregulates K(Ca)2.3 channels and ameliorates endothelial dysfunction in diet-induced obese mice
AMPK upregulates K(Ca)2.3 channels and ameliorates endothelial dysfunction in diet-induced obese mice
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NSTL
Elsevier
The opening of endothelial small-conductance calcium-activated potassium channels (K(Ca)2.3) is essential for endothelium-dependent hyperpolarization (EDH), which predominantly occurs in small resistance arteries. Adenosine monophosphate-activated protein kinase (AMPK), an important metabolic regulator, has been implicated in regulating endothelial nitric oxide synthase activity. However, it was unclear whether AMPK regulated endothelial K(Ca)2.3-mediated EDH-type vasodilation. Using bioinformatics analysis and myograph system, we investigated the regulation by AMPK of K(Ca)2.3 in human umbilical vein endothelial cells (HUVECs) or mouse second-order mesenteric resistance arteries. In HUVECs, AMPK activation either by activators (AICAR, A769662 and MK-8722) or expression of the constitutively active form of AMPK significantly upregulated K(Ca)2.3 expression. Such effects were abolished by AMPK inhibitor (compound C) or AMPK alpha 1-/alpha 2-siRNA, extracellular-signal-regulated-kinase 5 (ERK5) inhibitor (ERK5-IN-1), and specific siRNA to myocyte-enhancer factor 2 (MEF2) or kruppel-like factor 2/4 (KLF2/4). K(Ca)2.3 expression was significantly reduced in mesenteric resistance arteries in AMPK alpha 2 knockout mice when compared with littermate control mice. Furthermore, in high-fat diet fed mice, 2-week treatment with AICAR restored endothelial K(Ca)2.3 expression in mesenteric resistance arteries with improved endothelial dysfunction. Our results demonstrate that activation of AMPK upregulates K(Ca)2.3 channel expression through the ERK5-MEF2-KLF2/4 signaling pathway in vascular endothelium, which contributes to benefits through K(Ca)2.3-mediated EDH-type vasodilation in mesenteric resistance arteries.
NSTL
Elsevier
