Adderley Shaquria P, Joshi Chintamani N, Martin Danielle N, Tulis David Anthony
Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA.
Front Pharmacol. 2012 Feb 7;3:10. doi: 10.3389/fphar.2012.00010. eCollection 2012.
BAY 41-2272 (BAY), a stimulator of soluble guanylyl cyclase, increases cyclic nucleotides and inhibits proliferation of vascular smooth muscle cells (VSMCs). In this study, we elucidated mechanisms of action of BAY in its regulation of vasodilator-stimulated phosphoprotein (VASP) with an emphasis on VSMC phosphodiesterases (PDEs). BAY alone increased phosphorylation of VASP(Ser239) and VASP(Ser157), respective indicators of PKG and PKA signaling. IBMX, a non-selective inhibitor of PDEs, had no effect on BAY-induced phosphorylation at VASP(Ser239) but inhibited phosphorylation at VASP(Ser157). Selective inhibitors of PDE3 or PDE4 attenuated BAY-mediated increases at VASP(Ser239) and VASP(Ser157), whereas PDE5 inhibition potentiated BAY-mediated increases only at VASP(Ser157). In comparison, 8Br-cGMP increased phosphorylation at VASP(Ser239) and VASP(Ser157) which were not affected by selective PDE inhibitors. In the presence of 8Br-cAMP, inhibition of either PDE4 or PDE5 decreased VASP(Ser239) phosphorylation and inhibition of PDE3 increased phosphorylation at VASP(Ser239), while inhibition of PDE3 or PDE4 increased and PDE5 inhibition had no effect on VASP(Ser157) phosphorylation. These findings demonstrate that BAY operates via cAMP and cGMP along with regulation by PDEs to phosphorylate VASP in VSMCs and that the mechanism of action of BAY in VSMCs is different from that of direct cyclic nucleotide analogs with respect to VASP phosphorylation and the involvement of PDEs. Given a role for VASP as a critical cytoskeletal protein, these findings provide evidence for BAY as a regulator of VSMC growth and a potential therapeutic agent against vasculoproliferative disorders.
BAY 41-2272（BAY）是一种可溶性鸟苷酸环化酶刺激剂，可增加环核苷酸并抑制血管平滑肌细胞（VSMC）的增殖。在本研究中，我们阐明了BAY调节血管舒张刺激磷蛋白（VASP）的作用机制，重点研究了VSMC磷酸二酯酶（PDE）。单独使用BAY可增加VASP（Ser239）和VASP（Ser157）的磷酸化，分别是PKG和PKA信号传导的指标。IBMX是一种非选择性PDE抑制剂，对BAY诱导的VASP（Ser239）磷酸化无影响，但可抑制VASP（Ser157）的磷酸化。PDE3或PDE4的选择性抑制剂可减弱BAY介导的VASP（Ser239）和VASP（Ser157）的增加，而PDE5抑制仅增强BAY介导的VASP（Ser157）的增加。相比之下，8Br-cGMP可增加VASP（Ser239）和VASP（Ser157）的磷酸化，而选择性PDE抑制剂对此无影响。在存在8Br-cAMP的情况下，抑制PDE4或PDE5可降低VASP（Ser239）的磷酸化，抑制PDE3可增加VASP（Ser239）的磷酸化，而抑制PDE3或PDE4可增加VASP（Ser157）的磷酸化，PDE5抑制对其无影响。这些发现表明，BAY通过cAMP和cGMP以及PDE的调节作用使VSMC中的VASP磷酸化，并且BAY在VSMC中的作用机制在VASP磷酸化和PDE的参与方面与直接环核苷酸类似物不同。鉴于VASP作为一种关键细胞骨架蛋白的作用，这些发现为BAY作为VSMC生长调节剂和抗血管增殖性疾病的潜在治疗剂提供了证据。
