VEGF activates receptor-operated cation channels in human microvascular endothelial cells.
OBJECTIVE
Vascular endothelial growth factor (VEGF) exerts many of its effects by stimulating endothelial calcium influx, but little is known about channels mediating VEGF-induced cation entry. The aim of this study was to measure and characterize for the first time the VEGF-activated cation current in human microvascular endothelial cells (HMVECs).


RESULTS
Whole-cell patch-clamp recordings were made from HMVECs. During applied voltage ramps, VEGF activated a current that reversed at 0 mV, was sensitive to gadolinium, and required extracellular cations. Noise analysis yielded a single-channel conductance of 27 pS. The current was not dependent on intracellular calcium stores, and was not blocked by inositol triphosphate (IP3) receptor or serine/threonine kinase inhibition but was partially inhibited by flufenamic acid. A similar current was activated by 1-oleoyl-2-acetyl-sn-glycerol (OAG), a membrane-permeant analog of diacylglycerol (DAG). To determine whether VEGF could activate recombinant ion channels with similar properties, we investigated the effect of VEGF on Chinese hamster ovary cells cotransfected with VEGFR2 and the canonical transient receptor potential (TRPC) channels, TRPC3 or TRPC6. VEGF induced a similar current to that described above in VEGFR2-TRPC3 and VEGFR2-TRPC6 cells but not in cells transfected with either cDNA alone.


CONCLUSIONS
VEGF activates a receptor-operated cation current in HMVECs and OAG can activate directly a similar current in these cells. VEGF is also able to activate heterologously expressed TRPC3/6 channels through VEGFR2.
Cheng
H-W
HW
Microvascular Research Laboratories, Department of Physiology, University of Bristol, Southwell St, Bristol BS2 8EJ, UK.
James
A F
AF
Foster
R R
RR
Hancox
J C
JC
Bates
D O
DO
D000818:Animals; D016466:CHO Cells; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology*; D002412:Cations / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004075:Diglycerides / Q000494:pharmacology; D004553:Electric Conductivity; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008833:Microcirculation; D018408:Patch-Clamp Techniques; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism; D050052:TRPC Cation Channels / Q000378:metabolism; D000074287:TRPC6 Cation Channel; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000187:drug effects / Q000378:metabolism
D015220:Calcium Channels; D002412:Cations; D004075:Diglycerides; D011994:Recombinant Proteins; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; D042461:Vascular Endothelial Growth Factor A; C038237:1-oleoyl-2-acetylglycerol; D040301:Vascular Endothelial Growth Factor Receptor-2