Control of vascular smooth muscle cell growth by connexin 43.
Control of vascular smooth muscle cell growth by connexin 43.
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DOI：
10.3389/fphys.2012.00220
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发表时间：
2012
影响因子：
4
通讯作者：
Tulis DA
中科院分区：
文献类型：
--
作者：
Joshi CN;Martin DN;Shaver P;Madamanchi C;Muller-Borer BJ;Tulis DA
缝隙连接蛋白43（Cx43）是血管平滑肌细胞（VSMCs）中主要的缝隙连接蛋白，通过缝隙连接细胞间通讯（GJIC）调节离子和其他信号分子的运动，在维持正常血管功能中起重要作用，但目前对Cx43在VSMCs中的许多信号机制尚不清楚。本研究的目的是探讨Cx43调控VSMC增殖的机制。用cAMP类似物8Br-cAMP、可溶性鸟苷酸环化酶（sGC）刺激剂BAY 41-2272（BAY）或Cx诱导剂二烯丙基二硫化物（DADS）处理大鼠原代VSMC在72小时后与载体对照相比显著降低增殖。溴脱氧尿苷摄取显示6小时后DNA合成减少（p < 0.05），流式细胞术显示与载体对照相比，DADS处理的细胞16小时后S期细胞数量减少（40%）。在8Br-cAMP、8Br-cGMP、BAY或DADS处理270 min后，Cx43表达显著增加。抑制PKA、PKG或PKC可逆转8 Br-cAMP刺激的Cx43表达增加，而仅PKG或PKC抑制可逆转8 Br-cGMP和BAY刺激的总Cx43增加。有趣的是，DADS对Cx43表达的刺激不依赖于PKA、PKG或PKC。利用光漂白后的荧光恢复，只有8Br-cAMP或DADS增加了PKC介导的8Br-cAMP和PKG介导的DADS的GJIC。此外，与对照组相比，DADS显著增加MAPK敏感的Ser 255和Ser 279，细胞周期调节激酶敏感的Ser 262和PKC敏感的Ser 368的磷酸化，而8Br-cAMP仅显著增加Ser 279的磷酸化。这项研究表明，8Br-cAMP-和DADS-增强GJIC，而不是Cx43的表达和/或磷酸化起着重要的作用，在VSMC增殖的调节，并提供了新的见解Cx43在VSM的生长调节能力。
Connexin 43 (Cx43), the principal gap junction protein in vascular smooth muscle cells (VSMCs), regulates movement of ions and other signaling molecules through gap junction intercellular communication (GJIC) and plays important roles in maintaining normal vessel function; however, many of the signaling mechanisms controlling Cx43 in VSMCs are not clearly described. The goal of this study was to investigate mechanisms of Cx43 regulation with respect to VSMC proliferation. Treatment of rat primary VSMCs with the cAMP analog 8Br-cAMP, the soluble guanylate cyclase (sGC) stimulator BAY 41-2272 (BAY), or the Cx inducer diallyl disulfide (DADS) significantly reduced proliferation after 72 h compared with vehicle controls. Bromodeoxyuridine uptake revealed reduction (p < 0.05) in DNA synthesis after 6 h and flow cytometry showed reduced (40%) S-phase cell numbers after 16 h in DADS-treated cells compared with vehicle controls. Cx43 expression significantly increased after 270 min treatment with 8Br-cAMP, 8Br-cGMP, BAY or DADS. Inhibition of PKA, PKG or PKC reversed 8Br-cAMP-stimulated increases in Cx43 expression, whereas only PKG or PKC inhibition reversed 8Br-cGMP- and BAY-stimulated increases in total Cx43. Interestingly, stimulation of Cx43 expression by DADS was not dependent on PKA, PKG or PKC. Using fluorescence recovery after photobleaching, only 8Br-cAMP or DADS increased GJIC with 8Br-cAMP mediated by PKC and DADS mediated by PKG. Further, DADS significantly increased phosphorylation at MAPK-sensitive Serine (Ser)255 and Ser279, the cell cycle regulatory kinase-sensitive Ser262 and PKC-sensitive Ser368 after 30 min while 8Br-cAMP significantly increased phosphorylation only at Ser279 compared with controls. This study demonstrates that 8Br-cAMP- and DADS-enhanced GJIC rather than Cx43 expression and/or phosphorylation plays important roles in the regulation of VSMC proliferation and provides new insights into the growth-regulatory capacities of Cx43 in VSM.