Tomasek J J, Haaksma C J
Department of Anatomy, New York Medical College, Valhalla.
Anat Rec. 1991 Jun;230(2):175-82. doi: 10.1002/ar.1092300205.
The fibronexus is a close transmembrane association between fibronectin filaments and actin microfilaments. It has been found at the surfaces of fibroblasts in tissue culture, as well as within contracting granulation tissue. This specialized connection has been proposed to play an important role in the adhesive properties of fibroblasts. The purpose of this study is to determine whether the fibronexus is present in other contracting tissues besides granulation tissue, specifically in Dupuytren's diseased tissue. Dupuytren's disease is a pathologic condition in which the palmar aponeurosis becomes shortened leading to irreversible flexion of the digits. Shortening of the aponeurosis is believed to be an active cellular process. Extracellular filaments and actin microfilaments form close transmembrane associations at the surfaces of actin-rich fibroblasts in Dupuytren's disease. Extracellular filaments extend from the cell surface into the surrounding tissue connecting fibroblasts with collagen fibrils and adjacent cells. In this study we have used immunoelectron microscopy to demonstrate that the extracellular filaments that participate in these close transmembrane associations contain fibronectin. High voltage electron microscopy has been used to examine the three-dimensional relationships between the cytoskeleton and fibronectin filaments in Dupuytren's diseased tissue. We propose that the fibronexus is a dominant adhesive structure at the surface of fibroblasts in Dupuytren's diseased tissue. The fibronexus, by mediating cell-to-cell and cell-to-matrix attachments, may serve to transmit contractile forces generated by actin microfilaments in these cells throughout the diseased tissue.
纤维连接桥是纤连蛋白丝与肌动蛋白微丝之间紧密的跨膜连接。在组织培养中的成纤维细胞表面以及正在收缩的肉芽组织内均发现有纤维连接桥。有人提出这种特殊连接在成纤维细胞的黏附特性方面发挥重要作用。本研究的目的是确定除肉芽组织外，纤维连接桥是否存在于其他收缩组织中，特别是在杜普伊特伦挛缩病组织中。杜普伊特伦挛缩病是一种病理状况，其中掌腱膜缩短导致手指不可逆的屈曲。腱膜缩短被认为是一个活跃的细胞过程。在杜普伊特伦挛缩病中，细胞外丝和肌动蛋白微丝在富含肌动蛋白的成纤维细胞表面形成紧密的跨膜连接。细胞外丝从细胞表面延伸到周围组织，将成纤维细胞与胶原纤维和相邻细胞连接起来。在本研究中，我们使用免疫电子显微镜证明参与这些紧密跨膜连接的细胞外丝含有纤连蛋白。已使用高压电子显微镜检查杜普伊特伦挛缩病组织中细胞骨架与纤连蛋白丝之间的三维关系。我们提出纤维连接桥是杜普伊特伦挛缩病组织中成纤维细胞表面的主要黏附结构。纤维连接桥通过介导细胞间和细胞与基质的附着，可能有助于在整个患病组织中传递这些细胞中肌动蛋白微丝产生的收缩力。
