The cyclic GMP-protein kinase G pathway regulates cytoskeleton dynamics and motility in astrocytes
The cyclic GMP-protein kinase G pathway regulates cytoskeleton dynamics and motility in astrocytes
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DOI：
10.1111/j.1471-4159.2007.04464.x
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发表时间：
2007-07-01
影响因子：
4.7
通讯作者：
Garcia, Agustina
中科院分区：
文献类型：
--
作者：
Boran, Mariela Susana;Garcia, Agustina
我们先前已经证明，增加一氧化氮合酶(NO)表达的炎性化合物对星形胶质细胞中NO信使cGMP的水平具有双向影响。在本工作中，我们证明了NO依赖的cGMP的形成参与了脂多糖(LPS)诱导的大鼠小脑星形胶质细胞的形态变化。与此相一致的是，cGMP的通透性类似物二丁酰-cGMP和颗粒鸟苷环化酶的配基心钠素都能诱导星形胶质细胞突起的延长和分支，这是由于胶质纤维酸性蛋白(GFAP)和肌动蛋白细丝的快速、可逆和浓度依赖的重新分布而不引起蛋白水平的显著变化。在与神经元共同培养的星形胶质细胞中也观察到了这些效应。CGMP诱导的细胞骨架重排可被特异的蛋白激酶G抑制剂RP-8BR-PET-cGMPS阻止，并涉及RhoA GTP酶的下游抑制，因为在转染组分活性RhoA的细胞中没有观察到。此外，二丁酰-cGMP阻止RhoA-膜结合，这是其与效应器相互作用所必需的步骤。在体外划痕实验中，cGMP-蛋白激酶G通路的刺激也导致星形胶质细胞迁移增加，导致伤口加速闭合，如脑损伤后反应性胶质增生所见。这些结果表明，cGMP介导的通路可能调节星形胶质细胞的生理-病理相关反应。
We have previously demonstrated that inflammatory compounds that increase nitric oxide (NO) synthase expression have a biphasic effect on the level of the NO messenger cGMP in astrocytes. In this work, we demonstrate that NO-dependent cGMP formation is involved in the morphological change induced by lipopolysaccharide (LPS) in cultured rat cerebellar astroglia. In agreement with this, dibutyryl-cGMP, a permeable cGMP analogue, and atrial natriuretic peptide, a ligand for particulate guanylyl cyclase, are both able to induce process elongation and branching in astrocytes resulting from a rapid, reversible and concentration-dependent redistribution of glial fibrillary acidic protein (GFAP) and actin filaments without significant change in protein levels. These effects are also observed in astrocytes co-cultured with neurons. The cytoskeleton rearrangement induced by cGMP is prevented by the specific protein kinase G inhibitor Rp-8Br-PET-cGMPS and involves downstream inhibition of RhoA GTPase since is not observed in cells transfected with constitutively active RhoA. Furthermore, dibutyryl-cGMP prevents RhoA-membrane association, a step necessary for its interaction with effectors. Stimulation of the cGMP-protein kinase G pathway also leads to increased astrocyte migration in an in vitro scratch-wound assay resulting in accelerated wound closure, as seen in reactive gliosis following brain injury. These results indicate that cGMP-mediated pathways may regulate physio-pathologically relevant responses in astroglial cells.