Identification and characterization of KV7 channels within rat mesenteric endothelial cells

KV7 channel characterization in rat endothelial cells

Samuel N Baldwin1, Shaun L Sandow2, Gema Mondéjar-Parreño3, Jennifer B Stott1, Iain A Greenwood1
  1. Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St George’s University of London, London, UK.
  2. Biomedical Science, School of Health and Sports Science, University of the Sunshine Coast, Maroochydore, and Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia.
  3. Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain. Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain.

Word count: 3186 (excluding methods)

Acknowledgements

The authors would like to thank Miss Aditi Gunjal for her excellent assistance in wire Myography. S.N.B was funded by the British Heart Foundation (Grant #FS/18/41/33762) awarded to I.A.G.

Conflict of interest

The authors declare no conflict of interest.

Abstract

Background and purpose

KCNQ-encoded KV7 channels are expressed within vascular smooth muscle cells (VSMCs) and are key regulators of vascular reactivity, regulating resting tone and as functional targets of endogenous responses. Endothelial cells (ECs) form a paracrine signaling platform that line all blood vessels and regulate tone, but little is known of KV7 channels in vascular ECs. This study aims to characterize the expression and function of KV7 channels within rat mesenteric artery ECs.

Experimental approach

In rat mesenteric artery, KCNQ transcript and KV7 channel protein expression were determined via RT-qPCR, immunocytochemistry, immunohistochemistry and immunoelectron microscopy. Wire myography was used to determine vascular reactivity.

Key results

KCNQ transcript was identified in EC marker expressing cells using a reductive approach. KV7.4 and KV7.5 protein expression was determined in both isolated EC and VSMC and in whole vessels. Removal of ECs attenuated vasorelaxation to two structurally different KV7.2-5 activators S-1 and ML213. KIR2 blockers ML133, and BaCl also attenuated S-1 or ML213-mediated vasorelaxation in an endothelium-dependent process. KV7 inhibition attenuated receptor-dependent nitric oxide (NO)-mediated vasorelaxation to carbachol, but had no impact on relaxation to the NO donor, SNP.

Conclusions and implications

In rat mesenteric artery ECs, KV7.4 and KV7.5 channels are expressed, functionally interact with endothelial KIR2.x channels and contribute to endogenous eNOS-mediated relaxation. This study identifies KV7 channels as novel functional channels within rat mesenteric ECs and suggests that these channels are involved in NO release from the endothelium.

Key words

What is already known

KV7 channels and endothelial cells are key regulators of vascular tone.

What this study adds

Clinical significance

Endothelial KV7 channels represent novel targets in endothelial dysfunction.

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