Research Project
Grant-in-Aid for Scientific Research (B)
Sustained elevation of intracellular Ca^2+ concentration ([Ca^2+]i) has been implicated in many cellular events. We reported that sustained Ca^2+ influx through canonical transient receptor potential 3/6 (TRPC3/6) channels pathway leads to the activation of nuclear factor of activated T cells (NFAT), a Ca^2+-responsive transcriptional factor, and meditates hypertrophic responses in rat neonatal cardiac myocytes. We also demonstrated that TRPC6 channels participates in sustained Ca^2+ influx and NFAT activation by endothelin (ET)-1 treatment in cardiac fibroblasts. Expression of constitutively active (CA) G_α<12> or G_α<13> increased the expression of TRPC6 proteins and basal Ca^2+ influx activity. The treatment with ET-1 increased TRPC6 protein levels through G_α<12/13>, reactive oxygen species (ROS), and c-Jun N-terminal kinase (JNK)-dependent pathways. NFAT is activated by sustained increase in [Ca^2+]; through upregulated TRPC6. A G_α<12/13>-inhibitory polypeptide derived from regulator of G-protein signaling domain of p115-RhoGEF and a JNK inhibitor, SP600125, suppressed the ET-1-induced increase in expression of marker proteins of myofibroblast formation through G_α<12/13>-ROS-JNK pathway. The ET-1-induced myofibroblast formation was suppressed by overexpression of TRPC6 and CA-NFAT, while enhanced by TRPC6 siRNAs and cyclosporine A. These results suggest two opposite roles of G_α<12/13> in cardiac fibroblasts. First, G_α<12/13> mediate ET-1-induced myofibroblast formation. Second, G_α<12/13> mediate TRPC6 upregulation and NFAT activation that negatively regulates ET-1-induced myofibroblast formation. Furthermore, TRPC6 mediates hypertrophic responses in cardiac myocytes but suppresses fibrotic responses in cardiac fibroblasts. Thus, TRPC6 mediates opposite responses in cardiac myocytes and fibroblasts.
All 2007 2006 Other
All Journal Article (23 results) (of which Peer Reviewed: 4 results) Presentation (8 results)
Biochemical and Biophysical Research Communications 356
Pages: 275-285
Cellular Signalling 19
Pages: 1745-1753
医学のあゆみ 223
Pages: 464-468
Biochemical Biophysical Research Communications 356
Pages: 279-285
FASEB Journal 21
Pages: 2980-2993
Journal of Biological Chemistry 282
Pages: 23117-23128
Molecular Endocrinology 21
Pages: 2242-2254
Journal of Biological Chemistry 281
Pages: 31940-31949
EMBO Journal 25
Pages: 5305-5316
Cellular Signalling 18
Pages: 841-850
Journal of Pharmacological Sciences 101
Pages: 144-150
Journal of Pharmacological Sciences 102
Pages: 167-172
European Journal of Pharmacology 545
Pages: 100-108
Journal of Biological Chemistry 281(42)
EMBO Journal 25(22)
Cellular Signalling 18(6)
10018237777
10020345451
European Journal of Pharmacology 545(2-3)