Adhesive properties of isolated chick osteocytes in vitro
Adhesive properties of isolated chick osteocytes in vitro
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DOI：
10.1016/8756-3282(96)00010-5
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发表时间：
1996-04-01
期刊：
影响因子：
4.1
通讯作者：
Helfrich, MH
中科院分区：
文献类型：
--
作者：
Aarden, EM;Nijweide, PJ;Helfrich, MH
随着时间的推移，人们已经提出了骨细胞的不同功能，但现在普遍认为，它们最重要的任务是感知骨骼上机械负荷引起的应变。在细胞膜和细胞外基质之间的空间中，机械应变可以作为细胞外基质的变形或作为沿细胞沿着的流体剪切应力被感测的事实要求骨细胞与骨基质具有紧密（专门）接触。我们研究了分离的鸡骨细胞粘附的细胞外基质蛋白，以及这种粘附是否由称为整合素的特异性细胞粘附受体介导。比较成骨细胞与骨细胞的粘附特性。骨细胞（和成骨细胞）粘附在相同的基质上（即，I型和II型胶原、胶原纤维、骨桥蛋白、骨连接蛋白、纤连蛋白、纤维蛋白原、血小板反应蛋白和层粘连蛋白）。细胞铺展在基质之间变化，从血小板反应蛋白上的所有细胞圆形到骨桥蛋白、骨连接蛋白、玻连蛋白、纤连蛋白、纤维蛋白原和层粘连蛋白上的所有细胞完全铺展。粘附的骨细胞的百分比相当于所有基板上的成骨细胞粘附，除了骨桥蛋白和玻连蛋白，其中骨细胞粘附less.The骨细胞和成骨细胞的骨桥蛋白，骨连接蛋白，玻连蛋白，纤维蛋白原的粘附被强烈抑制，和纤维连接蛋白和层粘连蛋白适度，由RGD肽。对胶原蛋白没有发现RGD抑制作用。抗鸡整联蛋白α（v）β（3）的单克隆抗体（MAb）23 C6不干扰骨细胞和成骨细胞与基质蛋白的粘附，而抗鸡整联蛋白β亚基（1）（CSAT）的MAb强烈抑制与所有基质的粘附。用骨细胞特异性单克隆抗体（OB7.3、OB37.4和OB37.11）标记也不妨碍骨细胞与I型胶原、玻连蛋白和骨桥蛋白的粘附。与成骨细胞的大粘附斑块相比，骨细胞上的粘附位点较小，这通过干涉反射显微镜和黏着斑蛋白染色的免疫细胞化学方法证明。骨细胞粘附就其粘附的细胞外基质蛋白的范围而言类似于成骨细胞粘附。粘附由整合素β亚基（1）介导，但也涉及其他整合素或非整合素粘附受体。骨细胞通过与黏着斑蛋白共定位的小附着点与细胞外基质接触。骨基质和细胞骨架之间的这种连接对于骨细胞的机械应变感测可能是重要的，因为它提供了细胞外（机械）信号到细胞内信息的转导途径。
Different functions have been proposed for osteocytes over time, but it is now generally accepted that their most important task lies in the sensing of strain caused by mechanical loading on bone. The fact that mechanical strain can be sensed as deformation of the extracellular matrix or as fluid shear stress along the cell, in the space between cell membrane and extracellular matrix, requires that osteocytes have close (specialized) contact with the bone matrix. We studied to which extracellular matrix proteins isolated chicken osteocytes adhere and whether this adhesion is mediated by specific cell adhesion receptors called integrins. The adhesive properties of the osteocytes were compared with that of osteoblasts. Osteocytes (and osteoblasts) adhere to the same substrates (i.e., collagen types I and II, collagen fibers, osteopontin, osteonectin, fibronectin, fibrinogen, thrombospondin, and laminin). Cell spreading varied between substrates, from all cells rounded on thrombospondin to all cells fully spread out on osteopontin, osteonectin, vitronectin, fibronectin, fibrinogen, and laminin. The percentage of osteocytes adhered was equivalent to that of osteoblasts adhered on all substrates except osteopontin and vitronectin, where osteocytes adhered less. The adhesion of osteocytes and osteoblasts to osteopontin, osteonectin, vitronectin, and fibrinogen was strongly inhibited, and to fibronectin and laminin moderately, by an RGD peptide. No RGD inhibition was found on collagen. An antibody against chicken integrin alpha(v) beta(3), the monoclonal antibody (MAb) 23C6, did not interfere with the adhesion of osteocytes and osteoblasts to matrix proteins, whereas an MAb against chicken integrin subunit beta(1) (CSAT) strongly inhibited adhesion to all substrates. Labeling with osteocyte-specific MAbs (OB7.3, OB37.4, and OB37.11) also did not hinder the adhesion of osteocytes to collagen type I, vitronectin, and osteopontin. Adhesion sites on osteocytes were small compared with the large adhesion plaques of osteoblasts, as demonstrated by interference reflection microscopy and immunocytochemically by staining for vinculin. Osteocyte adhesion is analogous to osteoblast adhesion with regard to the range of extracellular matrix proteins to which they adhere. The adhesion is mediated by the integrin subunit beta(1), but other integrins or nonintegrin adhesion receptors are also involved. Osteocytes make contact with the extracellular matrix via small attachment points which colocalize with vinculin. This connection between the bone matrix and the cytoskeleton may be important for osteocytic sensing of mechanical strain, as it supplies a transduction route of extracellular (mechanical) signals into intracellular messages.