Genistein potentiates activity of the cation channel TRPC5 independently of tyrosine kinases
Article first published online: 3 MAR 2010
© 2010 The Authors. Journal compilation © 2010 The British Pharmacological Society
British Journal of Pharmacology
Volume 159, Issue 7, pages 1486–1496, April 2010
How to Cite
Wong, C.-O., Huang, Y. and Yao, X. (2010), Genistein potentiates activity of the cation channel TRPC5 independently of tyrosine kinases. British Journal of Pharmacology, 159: 1486–1496. doi: 10.1111/j.1476-5381.2010.00636.x
- Issue published online: 22 MAR 2010
- Article first published online: 3 MAR 2010
- Received 18 April 2009; revised 30 October 2009; accepted 17 November 2009
- calcium channel;
- transient receptor potential
Background and purpose: TRPC5 is a Ca2+-permeable channel with multiple modes of activation. We have explored the effects of genistein, a plant-derived isoflavone, on TRPC5 activity, and the mechanism(s) involved.
Experimental approach: Effects of genistein on TRPC5 channels were investigated in TRPC5-over-expressing human embryonic kidney 293 (HEK) cells and bovine aortic endothelial cells (BAECs) using fluorescent Ca2+ imaging and electrophysiological techniques.
Key results: In TRPC5-over-expressing HEK cells, genistein stimulated TRPC5-mediated Ca2+ influx, concentration dependently (EC50= 93 µM). Genistein and lanthanum activated TRPC5 channels synergistically. Effects of genistein on TRPC5 channels were mimicked by daidzein (100 µM), a genistein analogue inactive as a tyrosine kinase inhibitor, but not by known tyrosine kinase inhibitors herbimycin (2 µM), PP2 (20 µM) and lavendustin A (10 µM). Action of genistein on TRPC5 channels was not affected by an oestrogen receptor inhibitor ICI-182780 (50 µM) or a phospholipase C inhibitor U73122 (10 µM), suggesting genistein did not act through oestrogen receptors or phospholipase C. In BAECs, genistein (100 µM) stimulated TRPC5-mediated Ca2+ influx. In patch clamp studies, both genistein (50 µM) and daidzein (50 µM) augmented TRPC5-mediated whole-cell cation current in TRPC5 over-expressing HEK cells. Genistein stimulated TRPC5 channel activity in excised inside-out membrane patch, suggesting that its action was relatively direct and did not require cytosolic factors.
Conclusions and implications: The present study is the first to demonstrate stimulation of a TRP channel by isoflavones. Genistein is a lipophilic compound able to stimulate TRPC5 activity in TRPC5-over-expressing HEK cells and in native vascular endothelial cells.