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
- Vascular Biology Research Centre, Institute of Molecular and Clinical
Sciences, St George’s University of London, London, UK.
- 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.
- 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.
- SN Baldwin, SL Sandow, G Mondéjar-Parreño and JB Stott performed the
research.
- IA Greenwood and JB Stott designed the research study.
- SL Sandow contributed essential reagents or tools.
- SN Baldwin, SL Sandow and G Mondéjar-Parreño analysed the data.
- SN Baldwin and IA Greenwood wrote the paper.
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
- KV7 channel
- Endothelial cell
- Vascular smooth muscle cell
- KIR channel
What is already known
KV7 channels and endothelial cells are key regulators
of vascular tone.
What this study adds
- When stimulated, endothelial cell KV7 channels which
interact with KIR2.x channels.
- Endothelial KV7 channels contribute to
carbachol-mediated eNOS dependent relaxation.
Clinical significance
Endothelial KV7 channels represent novel targets in
endothelial dysfunction.
Abbreviations