Chondrocyte primary cilia shorten in response to osmotic challenge and are sites for endocytosis
Chondrocyte primary cilia shorten in response to osmotic challenge and are sites for endocytosis
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DOI：
10.1016/j.joca.2012.04.017
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发表时间：
2012-08-01
影响因子：
7
通讯作者：
Clark, A. L.
中科院分区：
文献类型：
--
作者：
Rich, D. R.;Clark, A. L.
目的：研究软骨部位和渗透压对未受干扰软骨中活软骨细胞初级纤毛发生率、长度和方向的影响。此外，我们对内吞标记物进行成像，以验证我们的假设，即纤毛袋是内吞作用的一个部位。材料和方法：我们使用完整小鼠股骨软骨细胞的离体活细胞共聚焦成像测量初级纤毛的发生率、长度和冠状面方向。测量取自左右股骨内侧和外侧髁的五个区域，也在渗透挑战一分钟后进行。利用透射电镜和免疫细胞化学技术表征软骨细胞初级纤毛在矢状面上的方向和位置，并确定网格蛋白包被的囊泡、内体和溶酶体蛋白以及CD44与纤毛囊的共定位。结果：软骨细胞初级纤毛长度在一分钟低渗透或高渗透刺激后显著减少，并且在不同髁间和每个髁表面上有所不同。软骨细胞初级纤毛的大部分长度位于膜内陷内，而不是从细胞膜突出，网格蛋白包被的囊泡，内体蛋白和CD44与纤毛袋共定位。结论：我们证明活的离体软骨细胞初级纤毛能够在几分钟内响应渗透挑战而缩短，并提供亚细胞和细胞证据表明，软骨细胞初级纤毛深深内陷在包含内吞作用部位的纤毛口袋中。(C) 2012国际骨关节炎学会。Elsevier Ltd.出版。版权所有。
Objective: The purpose of this study was to examine the influence of cartilage site and osmolarity on primary cilia incidence, length and orientation in live chondrocytes in undisturbed cartilage. Additionally, we imaged endocytotic markers to test our hypothesis that the ciliary pocket is a site for endocytosis.Materials and methods: We measured primary cilia incidence, length and orientation in the coronal plane using ex vivo live cell confocal imaging of intact murine femoral chondrocytes. Measurements were taken from five regions of the medial and lateral condyles of the left and right femur and also after one minute of osmotic challenge. Transmission electron microscopy and immunocytochemistry were used to characterize the orientation and position of chondrocyte primary cilia in the saggital plane and to determine the colocalization of clathrin coated vesicles, endosomal and lysosomal proteins and CD44 with the ciliary pocket.Results: Chondrocyte primary cilia length decreased significantly after a one minute hypo- or hyper-osmotic challenge and varied between condyles and across the surface of each condyle. The majority of the length of the chondrocyte primary cilia was positioned within a membranous invagination rather than projecting out from the cell membrane and clathrin coated vesicles, endosomal proteins and CD44 colocalised with the ciliary pocket.Conclusions: We demonstrate that live ex vivo chondrocyte primary cilia are capable of shortening within minutes in response to osmotic challenge and provide subcellular and cellular evidence that chondrocyte primary cilia are deeply invaginated in a ciliary pocket which contains sites for endocytosis. (C) 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.