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AMP-activated protein kinase activation regulates adhesion of monocytes to vascular endothelial cells and the underlying mechanism

BAI Hong-Bo, WANG Yun, ZHANG Yu-Hua, ZHANG Yuan

Department of Physiology, School of Basic Science, Guangzhou Medical University, Guangzhou 511436, China； Department of Cardiology, General Hospital of Guangzhou Military Command of People’s Liberation Army, Guangzhou 510010, China

Abstract

The present study was aimed to explore the effect of AMP-activated protein kinase (AMPK) on monocyte adhesion to vascular endothelial cells and underlying molecular mechanism. Tumor necrosis factor α (TNFα)-activated human aortic endothelial cells (HAECs) were treated with different concentrations of AMPK agonist 5-Aminoimidazole-4-carboxamide-1-β-D-ribonucleotide (AICAR) or AMPK inhibitor compound C. And other HAECs were overexpressed with constitutive active or dominant negative AMPK protein and then treated with TNFα. The rates of monocytes adhering to endothelial cells were detected by fluorescent staining. Intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mRNA levels and protein secretions were detected by quantitative PCR and ELISA, respectively. Acetylation of NF-κB p65 at lysine 221 site was assessed by Western blot. NF-κB p65 DNA binding activity was analyzed by an ELISA-based method. By using small interfering RNA based strategy, p300 expression in HAECs was down-regulated and then cells were incubated with TNFα. NF-κB p65 DNA binding activity, ICAM-1 and VCAM-1 expressions and adhesion rates were detected, respectively. The activity of p300 was also detected by ELISA. The results showed that AICAR treatment significantly reduced monocyte-endothelial adhesion rate, as well as ICAM-1 and VCAM-1 mRNA levels and protein secretions, in TNFα-activated HAECs. Moreover, transfection of constitutive active AMPKα but not dominant negative AMPKα strongly diminished TNFα-induced upregulation of ICAM-1 and VCAM-1 mRNA expressions and secretions, as well as monocyte-endothelial adhesion. Furthermore, AMPK activation decreased TNFα-mediated acetylation of NF-κB p65 at Lys221 site and reduced NF-κB p65 DNA binding activity. Silencing p300 by siRNA significantly abolished the effect of TNFα- induced adhesion molecules expression and monocyte-endothelial adhesion. Blocking AMPK activation by compound C almost completely reversed the effect of AICAR exerted on HAECs. These results suggest AMPK activation suppresses monocyte-endothelial adhesion, and the underlying mechanism is relevant to the inhibition of p300 activity and NF-κB p65 transcriptional activity.

Key words: AMP-activated protein kinase; endothelial cell ; intercellular cell adhesion molecule-1 ; vascular cell adhesion molecule-1 ; NF-κB

Received: 2015-08-11　　Accepted: 2015-11-25

Corresponding author: 张园　　E-mail: yuanzhang_1980@163.com

Citing This Article：

BAI Hong-Bo, WANG Yun, ZHANG Yu-Hua, ZHANG Yuan. AMP-activated protein kinase activation regulates adhesion of monocytes to vascular endothelial cells and the underlying mechanism. Acta Physiol Sin 2016; 68 (1): 41-49 (in Chinese with English abstract).