Cyclic GMP/PKG-dependent inhibition of TRPC6 channel activity and expression negatively regulates cardiomyocyte NFAT activation Novel mechanism of cardiac stress modulation by PDE5 inhibition.
Cyclic GMP/PKG-dependent inhibition of TRPC6 channel activity and expression negatively regulates cardiomyocyte NFAT activation Novel mechanism of cardiac stress modulation by PDE5 inhibition.
复制标题
DOI：
10.1016/j.yjmcc.2009.11.015
复制
发表时间：
2010-04
影响因子：
5
通讯作者：
Kass DA
中科院分区：
文献类型：
--
作者：
Koitabashi N;Aiba T;Hesketh GG;Rowell J;Zhang M;Takimoto E;Tomaselli GF;Kass DA
促进合成或抑制分解代谢(如西地那非抑制PDE5)增加的环状GMP可激活蛋白激酶G(PKG)，钝化心肌病理性肥厚。被抑制的钙调神经磷酸酶(CN)-NFAT(活化T细胞的核因子)信号似乎参与了这一过程，尽管目前还不清楚这是如何实现的。一种可能的机制涉及通过瞬时受体电位规范(TRPC)通道(特别是TRPC6)进入钙内而激活CN/NFAT。在这里，我们验证了PKG通过修改并抑制TRPC6电流来阻断CN/NFAT激活的假设，从而打破了涉及NFAT和依赖于NFAT的TRPC6上调的正反馈环。在体内，TRPC6的表达随着压力超负荷和血管紧张素(ATII)或内皮素(ET1)的刺激而升高。8BR-cGMP和sIL可降低ET1刺激的TRPC6表达和NFAT去磷酸化活性。如果TRPC6的启动子与非功能的NFAT结合位点发生突变，则TRPC6的表达没有上调，而结构性的NFAT触发了TRPC6的表达，而sIL不抑制TRPC6的表达。PKG使TRPC6磷酸化，T70和S322都是靶标。这两个位点在功能上是相关的，因为8BR-cGMP强烈抑制野生型TRPC6通道的电流，但在那些具有磷酸化沉默突变(T70A、S322A或S322Q)的通道中则没有。8BR-cGMP或sIL可阻断ATII或ET1刺激的NFAT激活和蛋白质合成增加。然而，T70A或S322Q TRPC6突变体可阻断这种抑制作用，而模拟磷酸化突变体(T70E、S322E以及两者的组合)则抑制NFAT的激活。因此，PDE5抑制通过PKG依赖的通道磷酸化来阻断TRPC6通道的激活和相关的CN/NFAT激活信号。
Increased cyclic GMP from enhanced synthesis or suppressed catabolism (e.g. PDE5 inhibition by sildenafil, SIL) activates protein kinase G (PKG) and blunts cardiac pathological hypertrophy. Suppressed calcineurin (Cn)-NFAT (nuclear factor of activated T-cells) signaling appears to be involved, though it remains unclear how this is achieved. One potential mechanism involves activation of Cn/NFAT by calcium entering via transient receptor potential canonical (TRPC) channels (notably TRPC6). Here, we tested the hypothesis that PKG blocks Cn/NFAT activation by modifying and thus inhibiting TRPC6 current to break the positive feedback loop involving NFAT and NFAT-dependent TRPC6 upregulation. TRPC6 expression rose with pressure-overload in vivo, and angiotensin (ATII) or endothelin (ET1) stimulation in neonatal and adult cardiomyocytes in vitro. 8Br-cGMP and SIL reduced ET1-stimulated TRPC6 expression and NFAT dephosphorylation (activity). TRPC6 upregulation was absent if its promoter was mutated with non-functional NFAT binding sites, whereas constitutively active NFAT triggered TRPC6 expression that was not inhibited by SIL. PKG phosphorylated TRPC6, and both T70 and S322 were targeted. Both sites were functionally relevant, as 8Br-cGMP strongly suppressed current in wild-type TRPC6 channels, but not in those with phospho-silencing mutations (T70A, S322A or S322Q). NFAT activation and increased protein synthesis stimulated by ATII or ET1 was blocked by 8Br-cGMP or SIL. However, transfection with T70A or S322Q TRPC6 mutants blocked this inhibitory effect, whereas phospho-mimetic mutants (T70E, S322E, and both combined) suppressed NFAT activation. Thus PDE5-inhibition blocks TRPC6 channel activation and associated Cn/NFAT activation signaling by PKG-dependent channel phosphorylation.
登录
查看更多内容
DOI：
10.1073/pnas.97.26.14772
发表时间：
2000-12-19
影响因子：
11.1
作者：
Dostmann, WRG;Taylor, MS;Tegge, WJ
通讯作者：
Tegge, WJ
DOI：
10.1073/pnas.072647999
发表时间：
2002-04-02
影响因子：
11.1
作者：
Bueno, OF;Wilkins, BJ;Molkentin, JD
通讯作者：
Molkentin, JD
DOI：
10.1152/ajpheart.01130.2008
发表时间：
2009-07-01
影响因子：
4.8
作者：
Chen, Jie;Crossland, Randy F.;Marrelli, Sean P.
通讯作者：
Marrelli, Sean P.
影响因子：
10.8
作者：
Hsu, Steven;Nagayama, Takahiro;Takimoto, Eiki
通讯作者：
Takimoto, Eiki
DOI：
10.1073/pnas.162100799
发表时间：
2002-08-20
影响因子：
11.1
作者：
Fiedler, B;Lohmann, SM;Wollert, KC
通讯作者：
Wollert, KC