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Liu L, Yang H, Kuang SJ, Zhang L, Zhou MY, Zeng P, Zhang MZ, Rao F, Zhou ZL, Deng CY. Contribution of calcium dysregulation to impaired coronary artery contraction in Zucker diabetic fatty rats. Clin Exp Pharmacol Physiol 2023; 50:158-168. [PMID: 36309970 DOI: 10.1111/1440-1681.13733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 10/08/2022] [Accepted: 10/23/2022] [Indexed: 01/05/2023]
Abstract
Diabetic coronary artery injury is closely associated with Ca2+ dysregulation, although the underlying mechanism remains unclear. This study explored the role and mechanism of Ca2+ handling in coronary artery dysfunction in type 2 diabetic rats. Zucker diabetic fatty (ZDF) rats were used as the type 2 diabetes mellitus model. The contractility of coronary artery rings induced by KCl, CaCl2 , 5-HT and U46619 was significantly lower in ZDF rats than in Zucker lean rats. Vasoconstriction induced by 5-HT and U46619 was greatly inhibited by nifedipine. However, in the presence of 1 μM nifedipine or in the Ca2+ -free KH solution containing 1 μM nifedipine, there was no difference in the vasoconstriction between Zucker lean and ZDF rats. Store-operated calcium channels (SOCs) were not involved in coronary vasoconstriction. The downregulation of contractile proteins and the upregulation of synthesized proteins were in coronary artery smooth muscle cells (CASMCs) from ZDF rats. Metformin reversed the reduction of vasoconstriction in ZDF rats. Taken together, L-type calcium channel is important for regulating the excitation-contraction coupling of VSMCs in coronary arteries, and dysregulation of this channel contributes to the decreased contractility of coronary arteries in T2DM.
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Affiliation(s)
- Lin Liu
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Zhuhai hospital affiliated with Jinan University (Zhuhai People's Hospital), Zhuhai, China.,School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Hui Yang
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Su-Juan Kuang
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Li Zhang
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,School of biological science and engineering, South China University of Technology, Guangzhou, China
| | - Meng-Yuan Zhou
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,School of biological science and engineering, South China University of Technology, Guangzhou, China
| | - Peng Zeng
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Meng-Zhen Zhang
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Fang Rao
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhi-Ling Zhou
- Zhuhai hospital affiliated with Jinan University (Zhuhai People's Hospital), Zhuhai, China
| | - Chun-Yu Deng
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.,School of biological science and engineering, South China University of Technology, Guangzhou, China
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Saarti M, Almukhtar H, Smith PA, Roberts RE. Effect of mitochondrial complex III inhibitors on the regulation of vascular tone in porcine coronary artery. Eur J Pharmacol 2021; 896:173917. [PMID: 33529727 DOI: 10.1016/j.ejphar.2021.173917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 01/06/2021] [Accepted: 01/26/2021] [Indexed: 11/30/2022]
Abstract
In order to gain insight into the regulation of vascular tone by mitochondria, the effects of mitochondrial complex III inhibitors on contractile responses in porcine isolated coronary arteries were investigated. Segments of porcine coronary arteries were set up for isometric tension recording and concentration response curves to contractile agents were carried out in the absence or presence of the complex III inhibitors antimycin A or myxothiazol. Activity of AMP kinase was determined by measuring changes in phosphorylation of AMP kinase at Thr172. Pre-incubation with 10 μM antimycin A (Qi site inhibitor), or myxothiazol (Qo site inhibitor) led to inhibition of the contraction to the thromboxane receptor agonist U46619. Similar effects were seen on contractile responses to extracellular calcium, and the L-type calcium channel opener BAY K 8644, suggesting that both antimycin A and myxothiazol inhibit calcium-dependent contractions. The inhibitory effect of antimycin A was still seen in the absence of extracellular calcium, indicating an additional effect on a calcium independent pathway. The AMP kinase inhibitor dorsomorphin (10 μM) prevented the inhibitory of antimycin A but not myxothiazol. Furthermore, antimycin A increased the phosphorylation of AMP kinase, indicating an increase in activity, suggesting that antimycin A also acts through this pathway. These data indicate that inhibition of complex III attenuates contractile responses through inhibition of calcium influx. However, inhibition of the Qi site can also inhibit the contractile response through activation of AMP kinase.
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Affiliation(s)
- Mohammed Saarti
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Hani Almukhtar
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Paul A Smith
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Richard E Roberts
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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Deng M, Su D, Xu S, Little PJ, Feng X, Tang L, Shen A. Metformin and Vascular Diseases: A Focused Review on Smooth Muscle Cell Function. Front Pharmacol 2020; 11:635. [PMID: 32457625 PMCID: PMC7227439 DOI: 10.3389/fphar.2020.00635] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/21/2020] [Indexed: 12/16/2022] Open
Abstract
Metformin has been used in diabetes for more than 60 years and has excellent safety in the therapy of human type 2 diabetes (T2D). There is growing evidence that the beneficial health effects of metformin are beyond its ability to improve glucose metabolism. Metformin not only reduces the incidence of cardiovascular diseases (CVD) in T2D patients, but also reduces the burden of atherosclerosis (AS) in pre-diabetes patients. Vascular smooth muscle cells (VSMCs) function is an important factor in determining the characteristics of the entire arterial vessel. Its excessive proliferation contributes to the etiology of several types of CVD, including AS, restenosis, and pulmonary hypertension. Current studies show that metformin has a beneficial effect on VSMCs function. Therefore, this review provides a timely overview of the role and molecular mechanisms by which metformin acts through VSMCs to protect CVD.
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Affiliation(s)
- Mingying Deng
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Dan Su
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Suowen Xu
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Peter J Little
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD, Australia.,Department of Pharmacy, Xinhua College of Sun Yat-sen University, Guangzhou, China
| | - Xiaojun Feng
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Liqin Tang
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Aizong Shen
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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Chen H, Vanhoutte PM, Leung SWS. Vascular adenosine monophosphate-activated protein kinase: Enhancer, brake or both? Basic Clin Pharmacol Toxicol 2019; 127:81-91. [PMID: 31671245 DOI: 10.1111/bcpt.13357] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/24/2019] [Indexed: 12/25/2022]
Abstract
Adenosine monophosphate-activated protein kinase (AMPK), expressed/present ubiquitously in the body, contributes to metabolic regulation. In the vasculature, activation of AMPK is associated with several beneficial biological effects including enhancement of vasodilatation, reduction of oxidative stress and inhibition of inflammatory reactions. The vascular protective effects of certain anti-diabetic (metformin and sitagliptin) or lipid-lowering (simvastatin and fenofibrate) therapeutic agents, of active components of Chinese medicinal herbs (resveratrol and berberine) and of pharmacological agents (AICAR, A769662 and PT1) have been attributed to the activation of AMPK (in endothelial cells, vascular smooth muscle cells and/or perivascular adipocytes), independently of changes in the metabolic profile (eg glucose tolerance and/or plasma lipoprotein levels), leading to improved endothelium-derived nitric oxide-mediated vasodilatation and attenuated endothelium-derived cyclooxygenase-dependent vasoconstriction. By contrast, endothelial AMPK activation with pharmacological agents or by genetic modification is associated with reduced endothelium-dependent relaxations in small blood vessels and elevated systolic blood pressure. Indeed, AMPK activators inhibit endothelium-dependent hyperpolarization (EDH)-type relaxations in superior mesenteric arteries, partly by inhibiting endothelial calcium-activated potassium channel signalling. Therefore, AMPK activation is not necessarily beneficial in terms of endothelial function. The contribution of endothelial AMPK in the regulation of vascular tone, in particular in the microvasculature where EDH plays a more important role, remains to be characterized.
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Affiliation(s)
- Hui Chen
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
| | - Paul Michel Vanhoutte
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China.,State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China.,Department of Cardiovascular and Renal Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Susan Wai Sum Leung
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
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Chen H, Vanhoutte PM, Leung SWS. Acute activation of endothelial AMPK surprisingly inhibits endothelium-dependent hyperpolarization-like relaxations in rat mesenteric arteries. Br J Pharmacol 2019; 176:2905-2921. [PMID: 31116877 DOI: 10.1111/bph.14716] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/04/2019] [Accepted: 05/08/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE Endothelium-dependent hyperpolarizations (EDHs) contribute to the regulation of peripheral resistance. They are initiated through opening of endothelial calcium-activated potassium channels (KCa ); the potassium ions released then diffuse to the underlying smooth muscle cells, causing hyperpolarization and thus relaxation. The present study aimed to examine whether or not AMPK modulates EDH-like relaxations in rat mesenteric arteries. EXPERIMENTAL APPROACH Arterial rings were isolated for isometric tension recording. AMPK activity and protein level were measured by ELISA and western blotting respectively. KEY RESULTS The AMPK activator, AICAR, reduced ACh-induced EDH-like relaxations and increased AMPK activity in preparations with endothelium; these responses were prevented by compound C, an AMPK inhibitor. AICAR inhibited relaxations induced by SKA-31 (opener of endothelial KCa ) but did not affect potassium-induced, hyperpolarization-attributable relaxations or increase AMPK activity in preparations without endothelium. A769662, another AMPK activator, not only caused a similar inhibition of relaxations to ACh and SKA-31 in preparations with endothelium but also inhibited hyperpolarization-attributable relaxations and augmented AMPK activity in rings without endothelium. Protein levels of total AMPKα, AMPKα1, or AMPKβ1/2 were comparable between preparations with and without endothelium. CONCLUSIONS AND IMPLICATIONS Activation of endothelial AMPK, by either AICAR or A769662, acutely inhibits EDH-like relaxations of rat mesenteric arteries. Furthermore, A769662 inhibits signalling downstream of smooth muscle hyperpolarization. In view of the major blunting effect of AMPK activation on EDH-like relaxations, caution should be applied when administering therapeutic agents that activate AMPK in patients with endothelial dysfunction characterized by reduced production and/or bioavailability of NO.
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Affiliation(s)
- Hui Chen
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Paul M Vanhoutte
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Susan W S Leung
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
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A769662 Inhibits Insulin-Stimulated Akt Activation in Human Macrovascular Endothelial Cells Independent of AMP-Activated Protein Kinase. Int J Mol Sci 2018; 19:ijms19123886. [PMID: 30563079 PMCID: PMC6321332 DOI: 10.3390/ijms19123886] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/03/2018] [Indexed: 01/15/2023] Open
Abstract
Protein kinase B (Akt) is a key enzyme in the insulin signalling cascade, required for insulin-stimulated NO production in endothelial cells (ECs). Previous studies have suggested that AMP-activated protein kinase (AMPK) activation stimulates NO synthesis and enhances insulin-stimulated Akt activation, yet these studies have largely used indirect activators of AMPK. The effects of the allosteric AMPK activator A769662 on insulin signalling and endothelial function was therefore examined in cultured human macrovascular ECs. Surprisingly, A769662 inhibited insulin-stimulated NO synthesis and Akt phosphorylation in human ECs from umbilical veins (HUVECs) and aorta (HAECs). In contrast, the AMPK activators compound 991 and AICAR had no substantial inhibitory effect on insulin-stimulated Akt phosphorylation in ECs. Inhibition of AMPK with SBI-0206965 had no effect on the inhibition of insulin-stimulated Akt phosphorylation by A769662, suggesting the inhibitory action of A769662 is AMPK-independent. A769662 decreased IGF1-stimulated Akt phosphorylation yet had no effect on VEGF-stimulated Akt signalling in HUVECs, suggesting that A769662 attenuates early insulin/IGF1 signalling. The effects of A769662 on insulin-stimulated Akt phosphorylation were specific to human ECs, as no effect was observed in the human cancer cell lines HepG2 or HeLa, as well as in mouse embryonic fibroblasts (MEFs). A769662 inhibited insulin-stimulated Erk1/2 phosphorylation in HAECs and MEFs, an effect that was independent of AMPK in MEFs. Therefore, despite being a potent AMPK activator, A769662 has effects unlikely to be mediated by AMPK in human macrovascular ECs that reduce insulin sensitivity and eNOS activation.
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Sekar P, Huang DY, Hsieh SL, Chang SF, Lin WW. AMPK-dependent and independent actions of P2X7 in regulation of mitochondrial and lysosomal functions in microglia. Cell Commun Signal 2018; 16:83. [PMID: 30458799 PMCID: PMC6245559 DOI: 10.1186/s12964-018-0293-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/01/2018] [Indexed: 12/24/2022] Open
Abstract
Background P2X7 is ubiquitously expressed in myeloid cells and regulates the pathophysiology of inflammatory diseases. Since mitochondrial function in microglia is highly associated with microglial functions in controlling neuronal plasticity and brain homeostasis, we interested to explore the roles of P2X7 in mitochondrial and lysosomal functions as well as mitophagy in microglia. Methods P2X7−/− bone marrow-derived macrophages (BMDM), primary microglia and BV-2 immortalized microglial cells were used to detect the particular protein expression by immunoblotting. Mitochondrial reactive oxygen species (mitoROS), intracellular calcium, mitochondrial mass and lysosomal integrity were examined by flow cytometry. Mitochondrial oxygen consumption rate (OCR) was recorded using Seahorse XF flux analyzer. Confocal microscopic images were performed to indicate the mitochondrial dynamics and mitophagy after P2X7 activation. Results In primary microglia, BV-2 microglial cells and BMDM, P2X7 agonist BzATP triggered AMPK activation and LC3II accumulation through reactive oxygen species (ROS) and CaMKKII pathways, and these effects were abolished by P2X7 antagonist A438079 and P2X7 deficiency. Moreover, we detected the dramatic decreases of mitochondrial OCR and mass following P2X7 activation. AMPK inhibition by compound C or AMPK silencing reversed the P2X7 actions in reduction of mitochondrial mass, induction of mitochondrial fission and mitophagy, but not in uncoupling of mitochondrial respiration. Interestingly, we found that P2X7 activation induced nuclear translocation of TFEB via an AMPK-dependent pathway and led to lysosomal biogenesis. Mimicking the actions of BzATP, nigericin also induced ROS-dependent AMPK activation, mitophagy, mitochondrial fission and respiratory inhibition. Longer exposure of BzATP induced cell death, and this effect was accompanied by the lysosomal instability and was inhibited by autophagy and cathepsin B inhibitors. Conclusion Altogether ROS- and CaMKK-dependent AMPK activation is involved in P2X7-mediated mitophagy, mitochondrial dynamics and lysosomal biogenesis in microglial cells, which is followed by cytotoxicity partially resulting from mitophagy and cathepsin B activation. Electronic supplementary material The online version of this article (10.1186/s12964-018-0293-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ponarulselvam Sekar
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Duen-Yi Huang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | | | - Shwu-Fen Chang
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Wan-Wan Lin
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan. .,Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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Endothelial AMP-Activated Kinase α1 Phosphorylates eNOS on Thr495 and Decreases Endothelial NO Formation. Int J Mol Sci 2018; 19:ijms19092753. [PMID: 30217073 PMCID: PMC6165563 DOI: 10.3390/ijms19092753] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 02/08/2023] Open
Abstract
AMP-activated protein kinase (AMPK) is frequently reported to phosphorylate Ser1177 of the endothelial nitric-oxide synthase (eNOS), and therefore, is linked with a relaxing effect. However, previous studies failed to consistently demonstrate a major role for AMPK on eNOS-dependent relaxation. As AMPK also phosphorylates eNOS on the inhibitory Thr495 site, this study aimed to determine the role of AMPKα1 and α2 subunits in the regulation of NO-mediated vascular relaxation. Vascular reactivity to phenylephrine and acetylcholine was assessed in aortic and carotid artery segments from mice with global (AMPKα-/-) or endothelial-specific deletion (AMPKαΔEC) of the AMPKα subunits. In control and AMPKα1-depleted human umbilical vein endothelial cells, eNOS phosphorylation on Ser1177 and Thr495 was assessed after AMPK activation with thiopental or ionomycin. Global deletion of the AMPKα1 or α2 subunit in mice did not affect vascular reactivity. The endothelial-specific deletion of the AMPKα1 subunit attenuated phenylephrine-mediated contraction in an eNOS- and endothelium-dependent manner. In in vitro studies, activation of AMPK did not alter the phosphorylation of eNOS on Ser1177, but increased its phosphorylation on Thr495. Depletion of AMPKα1 in cultured human endothelial cells decreased Thr495 phosphorylation without affecting Ser1177 phosphorylation. The results of this study indicate that AMPKα1 targets the inhibitory phosphorylation Thr495 site in the calmodulin-binding domain of eNOS to attenuate basal NO production and phenylephrine-induced vasoconstriction.
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