Post-transcriptional silencing of TRPC1 ion channel gene by RNA interference upregulates TRPC6 expression and store-operated Ca2+ entry in A7r5 vascular smooth muscle cells

WOS: 000269178100006PubMed ID: 19386284This study investigates functional consequences of TRPC1 ion channel downregulation observed in aging rat aorta by employing RNA interference in cultured vascular smooth muscle cells. For this purpose, A7r5 aortic smooth muscle cells were used in quantitative gene and protein expression as well as in functional analyses. According to quantitative RT-PCR results. TRPC3, TRPC4 and TRPC5 mRNAs were not at detectable levels. In siTRPC1-transfected cells, TRPC1 mRNA and protein levels were decreased by 40% and 64%; however, those of TRPC6 were drastically increased by 100% and 200%, respectively. In fura-2-loaded TRPC1 knockdown cells, despite the decreased TRPC1 levels, cyclopiazonic acid-induced Ca2+ entry and store-operated Ca2+ entry following Ca2+ addition were elevated by 77% and 135%, respectively. Results suggest that decrease in TRPC1 may be compensated by upregulated TRPC6 that possibly takes part in store-operated Ca2+ entry in vascular smooth muscle cells. (C) 2009 Elsevier Inc. All rights reserved.The Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [SBAG-3033, BIDEB-2211]; Ege UniversityEge University [BAP06ECZ013]This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK, SBAG-3033 to M.T. and graduate scholarship, BIDEB-2211 to C.S.) and in part by the Ege University (BAP06ECZ013 to M.T.). Authors thank Dr. G. Gonul for developing the apparatus that allow monitoring [Ca2+]i changes in cells