Endothelial AMP-activated protein kinase regulates blood pressure and coronary flow responses through hyperpolarization mechanism in mice

Budbazar Enkhjargal, Shigeo Godo, Ayuko Sawada, Nergui Suvd, Hiroki Saito, Kazuki Noda, Kimio Satoh, Hiroaki Shimokawa

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

OBJECTIVE - Vascular endothelium plays an important role to maintain cardiovascular homeostasis through several mechanisms, including endothelium-dependent hyperpolarization (EDH). We have recently demonstrated that EDH is involved in endothelial metabolic regulation in mice. However, it remains to be examined whether AMP-activated protein kinase (AMPK), an important metabolic regulator, is involved in EDH and if so, whether endothelial AMPK (eAMPK) plays a role for circulatory regulation. APPROACH AND RESULTS - We examined the role of eAMPK in EDH, using mice with endothelium-specific deficiency of α-catalytic subunit of AMPK, either α1 (eAMPKα1-/-α2+/+) or α2 (eAMPKα1+/+α 2-/-) alone or both of them (eAMPKα1 -/-α2-/-). We performed telemetry, organ chamber, electrophysiological, and Langendorff experiments to examine blood pressure, vascular responses, hyperpolarization of membrane potential, and coronary flow responses, respectively. Hypertension was noted throughout the day in eAMPKα1-/-α2-/- and eAMPKα1α2 but not in eAMPKα 1+/+α2-/- mice when compared with respective control. Importantly, endothelium-dependent relaxations, EDH, and coronary flow increase were all significantly reduced in eAMPKα1α2 and eAMPKα1 -/-α2-/- but not in eAMPKα 1-/-α2+/+ mice. In contrast, endothelium-independent relaxations to sodium nitroprusside (a NO donor), NS-1619 (a Ca2+-activated K+ channel opener), and exogenous H2O2 were almost comparable among the groups. In eAMPKα1-/-α2-/- mice, antihypertensive treatment with hydralazine or long-term treatment with metformin (a stimulator of AMPK) failed to restore EDH-mediated responses. CONCLUSIONS - These results provide the first direct evidence that α1 subunit of eAMPK substantially mediates EDH responses of microvessels and regulates blood pressure and coronary flow responses in mice in vivo, demonstrating the novel role of eAMPK in cardiovascular homeostasis.

Original languageEnglish
Pages (from-to)1505-1513
Number of pages9
JournalArteriosclerosis, thrombosis, and vascular biology
Volume34
Issue number7
DOIs
Publication statusPublished - 2014 Jul

Keywords

  • AMP-activated protein kinases
  • blood pressure
  • endothelial cells
  • endothelium-dependent hyperpolarization factor

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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