Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, United Kingdom.
Sci Rep. 2019 May 13;9(1):7317. doi: 10.1038/s41598-019-43821-3.
Ca-transcription coupling controls gene expression patterns that define vascular smooth muscle cell (VSMC) phenotype. Although not well understood this allows normally contractile VSMCs to become proliferative following vessel injury, a process essential for repair but which also contributes to vascular remodelling, atherogenesis and restenosis. Here we show that the Ca/HCO-sensitive enzyme, soluble adenylyl cyclase (sAC), links Ca influx in human coronary artery smooth muscle cells (hCASMCs) to 3',5'-cyclic adenosine monophosphate (cAMP) generation and phosphorylation of the transcription factor Ca/cAMP response element binding protein (CREB). Store-operated Ca entry (SOCE) into hCASMCs expressing the FRET-based cAMP biosensor H187 induced a rise in cAMP that mirrored cytosolic [Ca]. SOCE also activated the cAMP effector, protein kinase A (PKA), as determined by the PKA reporter, AKAR4-NES, and induced phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and CREB. Transmembrane adenylyl cyclase inhibition had no effect on the SOCE-induced rise in cAMP, while sAC inhibition abolished SOCE-generated cAMP and significantly reduced SOCE-induced VASP and CREB phosphorylation. This suggests that SOCE in hCASMCs activates sAC which in turn activates the cAMP/PKA/CREB axis. sAC, which is insensitive to G-protein modulation but responsive to Ca, pH and ATP, may therefore act as an overlooked regulatory node in vascular Ca-transcription coupling.
钙转录偶联控制着血管平滑肌细胞（VSMC）表型的基因表达模式。尽管这一机制尚未得到很好的理解，但它允许原本具有收缩功能的 VSMC 在血管损伤后增殖，这一过程对于修复至关重要，但也导致了血管重构、动脉粥样硬化和再狭窄。在这里，我们表明钙/碳酸氢敏感酶可溶性腺苷酸环化酶（sAC）将人冠状动脉平滑肌细胞（hCASMC）中的钙内流与 3'、5'-环腺苷酸（cAMP）的产生和转录因子钙/环腺苷酸反应元件结合蛋白（CREB）的磷酸化联系起来。表达基于 FRET 的 cAMP 生物传感器 H187 的 hCASMC 中的储存操作钙内流（SOCE）诱导 cAMP 的升高，该升高与细胞质[Ca]相匹配。SOCE 还通过 PKA 报告子 AKAR4-NES 激活了 cAMP 效应物蛋白激酶 A（PKA），并诱导了血管舒张刺激磷蛋白（VASP）和 CREB 的磷酸化。跨膜腺苷酸环化酶抑制对 SOCE 诱导的 cAMP 升高没有影响，而 sAC 抑制则消除了 SOCE 产生的 cAMP，并显著降低了 SOCE 诱导的 VASP 和 CREB 磷酸化。这表明 hCASMC 中的 SOCE 激活了 sAC，sAC 又激活了 cAMP/PKA/CREB 轴。sAC 对 G 蛋白调节不敏感，但对 Ca、pH 和 ATP 敏感，因此它可能是血管钙转录偶联中被忽视的调节节点。
