Immunocytochemical assessment of cell differentiation of podoplanin-positive osteoblasts into osteocytes in murine bone.
Immunocytochemical assessment of cell differentiation of podoplanin-positive osteoblasts into osteocytes in murine bone.
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免疫细胞化学评估小鼠骨中平足蛋白阳性成骨细胞向骨细胞分化的细胞。
DOI：
10.1007/s00418-020-01937-y
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Amizuka N.
中科院分区：
文献类型：
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作者：
Nagai T.;Hasegawa T.;Yimin;Yamamoto T.;Hongo H.;Abe M.;Yoshida T.;Yokoyama A.;Freitas PHL.;Li M.;Yokoyama A.;Amizuka N.
在这项研究中，我们研究了podoplanin/E11，CD44，肌动蛋白丝和磷酸化ezrin在小鼠股骨和胫骨成骨细胞分化成骨细胞的边缘的免疫定位。当在受激发射损耗显微镜下观察时，与podoplanin阴性成骨细胞不同，podoplanin阳性成骨细胞显示肌动蛋白丝沿着细胞膜的重排组装，其类似于嵌入的骨细胞。在干骺端，即，在骨重建部位，携带CD44的破骨细胞接近或接触podoplanin阳性的成骨细胞，但podoplanin阳性的成骨细胞也将CD44定位在它们自己的细胞表面上。这些podoplanin阳性的成骨细胞，其细胞表面上具有CD44或接近于具有CD44的破骨细胞，在细胞膜上显示磷酸化ezrin阳性。因此，CD44/podoplanin相互作用的细胞表面可能参与成骨细胞分化成骨细胞的干骺端，通过介导podoplanin驱动的ezrin磷酸化和随后的重组组装肌动蛋白丝。因此，在颅骨培养中给予CD44后，磷酸化ezrin的蛋白表达增加。相反，在建模网站，如皮质骨，podoplanin阳性成骨细胞均匀地定位在一定的时间间隔，甚至没有接触CD44阳性骨髓细胞，此外，他们也表现出磷酸化埃兹蛋白免疫反应沿着他们的细胞膜。总之，CD44/podoplanin相互作用似乎参与了骨重建区域成骨细胞向骨细胞的分化，但不参与建模部位。
In this study, we examined the immunolocalization of podoplanin/E11, CD44, actin filaments, and phosphorylated ezrin in the osteoblasts on the verge of differentiating into osteocytes in murine femora and tibiae. When observing under stimulated emission depletion microscopy, unlike podoplanin-negative osteoblasts, podoplanin-positive osteoblasts showed a rearranged assembly of actin filaments along the cell membranes which resembled that of embedded osteocytes. In the metaphysis, i.e., the bone remodeling site, CD44-bearing osteoclasts were either proximal to or in contact with podoplanin-positive osteoblasts, but the podoplanin-positive osteoblasts also localized CD44 on their own cell surface. These podoplanin-positive osteoblasts, which either possessed CD44 on their cell surface or were close to CD44-bearing osteoclasts, showed phosphorylated ezrin-positivity on the cell membranes. Therefore, the CD44/podoplanin interaction on the cell surface may be involved in the osteoblastic differentiation into osteocytes in the metaphyses, via the mediation of podoplanin-driven ezrin phosphorylation and the subsequent reorganized assembly of actin filaments. Consistently, the protein expression of phosphorylated ezrin was increased after CD44 administration in calvarial culture. Conversely, in modeling sites such as the cortical bones, podoplanin-positive osteoblasts were uniformly localized at certain intervals even without contact with CD44-positive bone marrow cells; furthermore, they also exhibited phosphorylated ezrin immunoreactivity along their cell membranes. Taken together, it seems likely that the CD44/podoplanin interaction is involved in osteoblastic differentiation into osteocytes in the bone remodeling area but not in modeling sites.