Rgulation of vascular smooth muscle by CA2+ and CAMP

该提案重点关注 Ca2 抑制腺苷酸环化酶 (AC3) 在调节血管平滑肌 (VSM) 增殖和平滑肌收缩中的作用。 cAMP 具有抗 VSM 增殖作用，并且它可以拮抗有丝分裂原的作用，从而通过激活 Erk/MAP 激酶途径刺激增殖。此外，cAMP介导由α-2-肾上腺素能激动剂引起的VSM松弛并抵消由α-1-肾上腺素能激动剂引起的血管收缩。我们假设 Ca2+ 对 AC3 的抑制通过解除 cAMP c 对增殖和平滑肌收缩的检查而在这两个过程中发挥重要作用。 AC3 受到 Gs 偶联受体（包括 '-肾上腺素能受体）的强烈刺激，并受到 Ca2+ 的抑制。 Ca2 抑制由 CaM 激酶 II (CaMKII) 介导，该激酶使 AC3 Ser-1076 磷酸化。为了探索 AC3 对 VSM 功能的作用，我们破坏了小鼠的 AC3 基因。本提案的目的是确定 Ca2 是否通过刺激 AC3 Ser-1076 磷酸化来抑制 VSM 中 AC3 的活性，确定与野生型小鼠相比，AC3 突变小鼠培养的 VSM 细胞的增殖是否增强，并确定 CaMKII 突变小鼠中培养的 VSM 细胞的增殖是否减少。此外，我们建议检查 AC3 突变体和 CaMKII 突变体小鼠的心脏动力学参数。这些研究应该提供有关促细胞分裂剂和肾上腺素能药物调节 VSM 功能的基本见解。

This proposal focuses on the role of the Ca2+ inhibited adenylyl cyclase (AC3) in the regulation of vascular smooth muscle (VSM) proliferation and smooth muscle contraction. cAMP is anti-proliferative for VSM and it antagonizes the actions of mitogens that stimulate proliferation through activation of the Erk/MAP kinase pathway. Furthermore, cAMP mediates relaxation of VSM caused by '-2-adrenergic agonists and counteracts vasoconstriction caused by a -1-adrenergic agonists. We hypothesize that Ca2+ inhibition of AC3 plays a major role in both processes by releaving the cAMP c check on proliferation and smooth muscle constriction. AC3 is strongly stimulated by Gs-coupled receptors including '-adrenergic receptors and it is inhibited by Ca2+. Ca2+ inhibition is mediated by CaM kinase II (CaMKII) which phosphorylates AC3 at Ser-1076. To explore the role of AC3 for VSM function we disrupted the AC3 gene in mice. The objectives of this proposal are to determine if Ca2+ inhibits the activity of AC3 in VSM by stimulating the phosphorylation of AC3 at Ser-1076, to determine if proliferation of cultured VSM cells from AC3 mutant mice is enhanced is enhanced compared to wild type mice, and to determine if proliferation of cultured VSM cells is reduced in CaMKII mutant mice. In addition, we propose to examine cardiodynamic parameters in AC3 mutant and CaMKII mutant mice. These studies should provide fundamental insight concerning the regulation of VSM functions by mitogens and adrenergic agents.