Journal
CARDIOVASCULAR RESEARCH
Volume 91, Issue 3, Pages 472-482Publisher
OXFORD UNIV PRESS
DOI: 10.1093/cvr/cvr102
Keywords
Endothelial function; Hypoxia-reoxygenation; Ion channel; Nitric oxide
Categories
Funding
- Research Grant Council of Hong Kong [CUHK4651/07M, 4789/09M]
- CUHK Li Ka Shing Institute of Health Sciences, Hong Kong [2041561]
- Tianjin Municipal Science & Technology Commission [09ZCZDSF04200, 10JCYBJC26400]
- Ministry of Science & Technology, China [2009DFB30560, 2010CB529502]
- Providence St Vincent Medical Foundation, Portland, OR, USA
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Aims Intracellular Ca2+ ([Ca2+]i) regulation in endothelial cells depends on transient receptor potential channels (TRPs), and the role of canonical TRPs (TRPCs) during hypoxia-reoxygenation (H-R) is unclear. We hypothesized that TRPC3 contributes to endothelial nitric oxide (NO) release and that H-R may reduce TRPC3 activity and the associated endothelial function, including NO release. Methods and results Measurements of [Ca2+]i and patch-clamp study in primary cultured porcine coronary endothelial cells, measurements of NO and endothelium-dependent relaxation in porcine coronary arteries, and RT-PCR and western blot were conducted. Pre-treatment with SKF96365 (an inhibitor of TRPCs) or the selective TRPC3 inhibitor Pyr3 significantly decreased bradykinin-induced vasorelaxation. One hour of hypoxia followed by reoxygenation significantly reduced the vasorelaxation (70.3 +/- 6.4 vs. 88.9 +/- 3.5%) and NO concentration (24.0 +/- 1.3 vs. 45.2 +/- 2.8 nmol/L), and they were restored by pre-incubation with the TRPC3/6/7 activator 1-oleoyl-2-acetyl-sn-glycerol (96.4 +/- 1.8% and 41.1 +/- 4.7 nmol/L, respectively). In porcine coronary endothelial cells, H-R inhibited bradykinin-activated membrane current (8.6 +/- 0.4 vs. 14.0 +/- 1.5 pA/pF) and Pyr3-sensitive TRPC3 current (3.8 +/- 0.3 vs. 6.3 +/- 0.6 pA/pF; P, 0.01). H-R also inhibited bradykinin-induced Ca2+ influx and the Ca2+ influx via TRPC3. Cell surface expression of TRPC3 was decreased after H-R. Conclusions We have, for the first time, demonstrated that Ca2+ entry via endothelial TRPC3 contributes to NO release and have revealed that H-R is associated with inhibition of TRPC3 activity. Inhibition of channel trafficking to the cell surface is involved in the underlying mechanism of the decrease of TRPC3 current and the reduction in Ca2+ entry through TRPC3 during H-R. This study suggests that TRPC3 may have the potential to be a new target for endothelial protection during H-R.
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