TRPV1 mediates cellular uptake of anandamide and thus promotes endothelial cell proliferation and network-formation.
Anandamide (N-arachidonyl ethanolamide, AEA) is an endogenous cannabinoid that is involved in various pathological conditions, including cardiovascular diseases and tumor-angiogenesis. Herein, we tested the involvement of classical cannabinoid receptors (CBRs) and the Ca(2+)-channel transient receptor potential vanilloid 1 (TRPV1) on cellular AEA uptake and its effect on endothelial cell proliferation and network-formation. Uptake of the fluorescence-labeled anandamide (SKM4-45-1) was monitored in human endothelial colony-forming cells (ECFCs) and a human endothelial-vein cell line (EA.hy926). Involvement of the receptors during AEA translocation was determined by selective pharmacological inhibition (AM251, SR144528, CID16020046, SB366791) and molecular interference by TRPV1-selective siRNA-mediated knock-down and TRPV1 overexpression. We show that exclusively TRPV1 contributes essentially to AEA transport into endothelial cells in a Ca(2+)-independent manner. This TRPV1 function is a prerequisite for AEA-induced endothelial cell proliferation and network-formation. Our findings point to a so far unknown moonlighting function of TRPV1 as Ca(2+)-independent contributor/regulator of AEA uptake. We propose TRPV1 as representing a promising target for development of pharmacological therapies against AEA-triggered endothelial cell functions, including their stimulatory effect on tumor-angiogenesis.
Institute for Molecular Biology and Biochemistry, Medical University of Graz, A-8010 Graz, Austria.
Nicole A
NA
Hofmann
Institute for Molecular Biology and Biochemistry, Medical University of Graz, A-8010 Graz, Austria.
Sonja
S
Barth
Institute for Molecular Biology and Biochemistry, Medical University of Graz, A-8010 Graz, Austria.
Markus
M
Waldeck-Weiermair
Institute for Molecular Biology and Biochemistry, Medical University of Graz, A-8010 Graz, Austria.
Christiane
C
Klec
Experimental and Clinical Cell Therapy Institute, Paracelsus Medical University, A-5020 Salzburg, Austria.
Dirk
D
Strunk
Institute for Molecular Biology and Biochemistry, Medical University of Graz, A-8010 Graz, Austria.
Roland
R
Malli
Institute for Molecular Biology and Biochemistry, Medical University of Graz, A-8010 Graz, Austria wolfgang.graier@medunigraz.at.
Wolfgang F
WF
Graier
anandamide transport; anandamide, AEA; angiogenesis; endothelial colony-forming cells, ECFC; network-formation; proliferation; transient receptor potential vanilloid 1, TRPV1