Cholesterol depletion impairs vascular reactivity to endothelin-1 by reducing store-operated Ca2+ entry dependent on TRPC1.

Abstract

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.

• Authors: Andreas Bergdahl, Maria F Gomez, Karl Dreja, Shang-Zhong Xu, Mikael Adner, David J Beech, Jonas Broman, Per Hellstrand, Karl Swärd
• Journal: Circulation research (Circ Res) Vol. 93 Issue 9 Pg. 839-47 (Oct 31 2003) ISSN: 1524-4571 [Electronic] United States
• PMID: 14551243 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Calcium Channels
• Cav1 protein, rat
• Caveolin 1
• Caveolins
• Endothelin-1
• Ion Channels
• Ligands
• Receptor, Endothelin A
• TRPC Cation Channels
• TRPC3 cation channel
• Trpc6 protein, rat
• transient receptor potential cation channel, subfamily C, member 1
• Cholesterol
• Calcium

Topics

• Animals
• Arteries (drug effects, physiology)
• Basilar Artery (drug effects, physiology)
• Binding, Competitive (drug effects)
• Calcium (metabolism)
• Calcium Channels (metabolism)
• Caveolin 1
• Caveolins (metabolism)
• Cholesterol (deficiency, metabolism, pharmacology)
• Culture Techniques
• Dose-Response Relationship, Drug
• Endothelin-1 (pharmacology)
• Female
• Ion Channels (metabolism)
• Ligands
• Rats
• Rats, Sprague-Dawley
• Receptor, Endothelin A (metabolism)
• TRPC Cation Channels
• Tail (blood supply)
• Vasomotor System (drug effects, physiology)