Cholesterol depletion impairs vascular reactivity to endothelin-1 by reducing store-operated Ca2+ entry dependent on TRPC1.
The reactivity of the vascular wall to endothelin-1 (ET-1) is influenced by cholesterol, which is of possible importance for the progression of atherosclerosis. To elucidate signaling steps affected, the cholesterol acceptor methyl-beta-cyclodextrin (mbetacd, 10 mmol/L) was used to manipulate membrane cholesterol and disrupt caveolae in intact rat arteries. In endothelium-denuded caudal artery, contractile responsiveness to 10 nmol/L ET-1 (mediated by the ETA receptor) was reduced by mbetacd and increased by cholesterol. Neither ligand binding nor colocalization of ETA and caveolin-1 was affected by mbetacd. Ca2+ inflow via store-operated channels after depletion of intracellular Ca2+ stores was reduced in mbetacd-treated caudal arteries, as shown by Mn2+ quench rate and intracellular [Ca2+] response. Expression of TRPC1, 3, and 6 was detected by reverse transcriptase-polymerase chain reaction, and colocalization of TRPC1 with caveolin-1 was reduced by mbetacd, as seen by immunofluorescence. Part of the contractile response to ET-1 was inhibited by Ni2+ (0.5 mmol/L) and by a TRPC1 blocking antibody. In the basilar artery, exhibiting less store-operated channel activity than the caudal artery, ET-1-induced contractions were insensitive to the TRPC1 blocking antibody and to mbetacd. Increased store-operated channel activity in basilar arteries after organ culture correlated with increased sensitivity of ET-1 contraction to mbetacd. These results suggest that cholesterol influences vascular reactivity to ET-1 by affecting the caveolar localization of TRPC1.
Bergdahl
Andreas
A
Department of Physiological Sciences, Lund University, Lund, Sweden.
Gomez
Maria F
MF
Dreja
Karl
K
Xu
Shang-Zhong
SZ
Adner
Mikael
M
Beech
David J
DJ
Broman
Jonas
J
Hellstrand
Per
P
Swärd
Karl
K
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000502:physiology; D001488:Basilar Artery / Q000187:drug effects / Q000502:physiology; D001667:Binding, Competitive / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism; D002784:Cholesterol / Q000172:deficiency* / Q000378:metabolism / Q000494:pharmacology; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000494:pharmacology*; D005260:Female; D007473:Ion Channels / Q000378:metabolism; D008024:Ligands; D051381:Rats; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A / Q000378:metabolism; D050052:TRPC Cation Channels; D013623:Tail / Q000098:blood supply; D014666:Vasomotor System / Q000187:drug effects* / Q000502:physiology*
D015220:Calcium Channels; C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D019332:Endothelin-1; D007473:Ion Channels; D008024:Ligands; D044022:Receptor, Endothelin A; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; C492145:Trpc6 protein, rat; C096351:transient receptor potential cation channel, subfamily C, member 1; D002784:Cholesterol; D002118:Calcium