Polarity of osteoblasts and osteoblast-like UMR-108 cells
Polarity of osteoblasts and osteoblast-like UMR-108 cells
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DOI：
10.1359/jbmr.1999.14.8.1338
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发表时间：
1999-08-01
影响因子：
6.2
通讯作者：
Tuukkanen, J
中科院分区：
文献类型：
--
作者：
Ilvesaro, J;Metsikkö, K;Tuukkanen, J
囊膜病毒，如水泡性口炎病毒（VSV）和流感病毒，已被广泛用于研究上皮细胞极性。VSV感染的上皮细胞的病毒颗粒从基底外侧膜出芽，基底外侧膜与内部环境和血液供应接触。流感病毒感染的细胞从面向外部环境的顶端表面出芽病毒颗粒。本研究利用骨肉瘤细胞系UMR-108和骨内膜成骨细胞原位培养研究了间充质成骨细胞的极性。免疫荧光共聚焦显微镜显示，VSV糖蛋白（VSV G）的目标是面向培养基的表面。在骨内膜成骨细胞中，VSV G蛋白定位于面向骨髓和循环的表面，而流感病毒血凝素（HA）定位于UMR-108细胞面向骨基质的表面。电子显微镜显示，在细胞作为单层生长的情况下，VSV颗粒从面向培养基的表面出芽，而流感病毒从面向骨基质的表面出芽。当细胞重叠时，这种极性丧失。细胞表面生物素化显示55%的VSV G蛋白被生物素化，而流感病毒HA仅22%被生物素化。这些结果表明，成骨细胞在其生命周期的某些点被极化。成骨细胞的骨附着质膜是顶端的，而循环或面向骨髓的质膜本质上是基底外侧的。
Enveloped viruses, such as vesicular stomatitis virus (VSV) and Influenza virus, have been widely used in studying epithelial cell polarity. Viral particles of VSV-infected epithelial cells bud from the basolateral membrane, which is in contact with the internal milieu and the blood supply. Influenza-infected cells bud viral particles from the apical surface facing the external milieu. This feature can be utilized in labeling polarized membrane domains, We studied the polarity of mesenchymal osteoblasts using osteosarcoma cell line UMR-108 and endosteal osteoblasts in situ in bone tissue cultures. Immunofluorescence confocal microscopy revealed that the VSV glycoprotein (VSV G) was targeted to the culture medium-facing surface. In endosteal osteoblasts, VSV G protein was found in the surface facing bone marrow and circulation, On the contrary, Influenza virus hemagglutinin (HA) was localized to the bone substrate-facing surface of the UMR-108 cells. Electron microscopy showed that in the cases where the cells were growing as a single layer, VSV particles were budding from the culture medium-facing surface, whereas Influenza viruses budded from the bone substrate-facing surface. When the cells overlapped, this polarity was lost, Cell surface biotinylation revealed that 55% of VSV G protein was biotinylated, whereas influenza virus HA was only 22% biotinylated, These findings suggest that osteoblasts are polarized at some point of their life cycle. The bone-attaching plasma membrane of osteoblasts is apical, and the circulation or bone marrow-facing plasma membrane is basolateral in nature.