Contractile proteins in pericytes at the blood-brain and blood-retinal barriers
Contractile proteins in pericytes at the blood-brain and blood-retinal barriers
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DOI：
10.1023/a:1011965307612
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发表时间：
2001-01-01
期刊：
影响因子：
--
通讯作者：
Allt, G
中科院分区：
文献类型：
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作者：
Bandopadhyay, R;Orte, C;Allt, G
来自各种来源的证据表明，周细胞具有收缩特性，因此可能在毛细血管血流的调节中起作用。然而，有人认为收缩性不是周细胞的普遍功能，并且真正毛细血管周围的周细胞显然缺乏收缩机制。本研究采用了多种技术来研究收缩蛋白在中枢神经系统周细胞的表达。脑和视网膜的冷冻切片、视网膜全标本和分离的脑毛细血管的免疫印迹的免疫细胞化学结果表明，在大量的中毛细血管周细胞中，肌动蛋白的平滑肌同种型（α-SM肌动蛋白）强烈表达。超微结构水平的免疫金标记显示，毛细血管中的α-SM肌动蛋白表达仅限于周细胞，而内皮细胞为阴性。与α-SM肌动蛋白相比，非肌肉肌球蛋白的浓度较低。相比之下，平滑肌肌球蛋白亚型，缺席。周细胞的中间丝蛋白波形蛋白呈强阳性，但缺乏结蛋白，这是一贯发现在血管平滑肌细胞。这些结果增加了对CNS微血管周细胞的收缩作用的支持，类似于血管平滑肌细胞。
Evidence from a variety of sources suggests that pericytes have contractile properties and may therefore function in the regulation of capillary blood flow. However, it has been suggested that contractility is not a ubiquitous function of pericytes, and that pericytes surrounding true capillaries apparently lack the machinery for contraction. The present study used a variety of techniques to investigate the expression of contractile proteins in the pericytes of the CNS. The results of immunocytochemistry on cryosections of brain and retina, retinal whole-mounts and immunoblotting of isolated brain capillaries indicate strong expression of the smooth muscle isoform of actin (alpha -SM actin) in a significant number of mid-capillary pericytes. Immunogold labelling at the ultrastructural level showed that alpha -SM actin expression in capillaries was exclusive to pericytes, and endothelial cells were negative. Compared to alpha -SM actin, non-muscle myosin was present in lower concentrations. By contrast, smooth muscle myosin isoforms, were absent. Pericytes were strongly positive for the intermediate filament protein vimentin, but lacked desmin which was consistently found in vascular smooth muscle cells. These results add support for a contractile role in pericytes of the CNS microvasculature, similar to that of vascular smooth muscle cells.