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Ultrastructural analysis of the mechanism of the contraction of splenic sinus endothelial cells

脾窦内皮细胞收缩机制的超微结构分析

基本信息

批准号：
14570032
负责人：
UEHARA Kiyoko
金额：
$ 2.24万
依托单位：
Fukuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14570032/
关键词：
endothelial cells caveolae Ca2+ storing endoplasmic reticulum IP3R ryanodine receptor stress fiber spleen rat カベオラ脾洞内皮細胞 IP_3Rリセプターリアノジンリセプター微細構造

项目摘要

Endothelial cells of the splenic sinus have been previously investigated as a critical site for controlling blood cell passage through the splenic cord, and they have also been shown to be ultrastructurally quite different from other vascular endothelial cells. Particularly prominent are their shape and arrangement, like the staves of a barrel, with a highly ordered network of contractile stress fibers running longitudinally in their basal part. in addition, tubulovesicular structures in close apposition to abundant caveolae and stress fibers are conspicuous. An elevation in intracellular free Ca2+ concentration plays a crucial role in the regulation of endothelial vascular functions and, furthermore, agonists and/or mechanical stress also evoke Ca2+ oscillations. The exact mechanisms contributing to Ca2+ oscillation are unknown, but oscillatory changes in IP3-receptor sensitivity, tune-resolved Ca2+ release from different Ca2+-pools, the rhythmic entry of Ca2+ through non-selective ca … More tion channels, changes in cellular morphology and the involvement of endoplasmic Ca2+-ATPases have been proposed. Considering that the stress **ers in sinus endothelial cells are contracted, caveolae, Ca2+storing ER, IP3R, and RyR in sinus endothelial cells may be involved in the constriction of stress. fibers. in addition, the presence and contribution to Ca2+-oscillations of RyR in endothelial cells have been shown, but the localization in endothelial cells is not quite clear. Therefore, the distribution of caveolac and Ca2+storing ER and the localization of IP3R and RyR in the sinus endothelial cells of the rat spleen were examined by confocal laser scanning and electron microscopy.Immunofluorescence microscopy of tissue cryosections revealed IP3R and RyR to be localized in the subplasmalemmal area and cytoplasm of sinus endothelial cells. By electron microscopy of tissue sections treated with osmium ferricyanide to selectively stain the sarcoplasmic reticulum and transverse tubules in muscle cells, electron-dense tubulovesicular structures were observed to be in close apposition to caveolac and the plasma membrane. Immunogold electron microscopy revealed IP3R and RyR to be present in the tubulovesicular structure in the subplasmalemmal area of sinus endothelial cells. It is speculated that IP3R and RyR in sinus endothelial cells is involved in the constriction of stress fibers. Less

脾窦的内皮细胞以前已经被研究为控制血细胞通过脾索的关键部位，并且它们也被证明在超微结构上与其他血管内皮细胞完全不同。特别突出的是它们的形状和排列，就像桶的板条，在它们的基部有一个高度有序的收缩应力纤维网络。此外，与大量小窝和应力纤维紧密并列的管泡结构也很明显。细胞内游离Ca 2+浓度的升高在内皮血管功能的调节中起着至关重要的作用，此外，激动剂和/或机械应力也引起Ca 2+振荡。导致Ca 2+振荡的确切机制尚不清楚，但IP 3-受体敏感性的振荡变化、不同Ca 2+池的调谐分辨Ca 2+释放、Ca 2+通过非选择性钙通道的节律性进入等都可能导致Ca 2+振荡。 ...更多信息离子通道，细胞形态的变化和内质网Ca ~（2+）-ATP酶的参与已被提出。提示窦内皮细胞的应激反应是收缩的，窦内皮细胞的小窝、贮钙ER、IP 3R和RyR可能参与了应激反应的收缩。纤维另外，已经显示了RyR在内皮细胞中的存在和对Ca 2+振荡的贡献，但是在内皮细胞中的定位不十分清楚。因此，我们用激光共聚焦扫描和电子显微镜观察了Caveolac和Ca 2+储存ER在大鼠脾窦内皮细胞中的分布以及IP 3R和RyR在脾窦内皮细胞中的定位，免疫荧光显微镜观察显示IP 3R和RyR定位于脾窦内皮细胞的质膜下区和胞浆中。通过用铁氰化锇处理的组织切片的电子显微镜选择性地染色肌细胞中的肌浆网和横小管，观察到电子致密的管状泡状结构与小窝和质膜紧密并列。免疫金电子显微镜显示IP 3R和RyR存在于窦内皮细胞质膜下区域的管状结构中。推测窦内皮细胞中的IP 3R和RyR参与了应力纤维的收缩。少