Structural and compositional diversity of fibrillin microfibrils in human tissues.
Structural and compositional diversity of fibrillin microfibrils in human tissues.
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DOI：
10.1074/jbc.ra117.001483
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发表时间：
2018-04-06
期刊：
影响因子：
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通讯作者：
Sherratt MJ
中科院分区：
文献类型：
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作者：
Eckersley A;Mellody KT;Pilkington S;Griffiths CEM;Watson REB;O'Cualain R;Baldock C;Knight D;Sherratt MJ
包含原纤维蛋白微原纤维和弹性蛋白的弹性纤维存在于许多组织中，包括皮肤、肺和动脉，它们赋予弹性和复原力。尽管原纤维蛋白微原纤维发挥着独特的组织特异性功能作用，但尚不清楚其超微结构和组成在富含弹性蛋白（皮肤）和缺乏弹性蛋白（睫状体和小带）的器官之间或在培养细胞体外合成后是否存在差异。在这里，我们使用原子力显微镜，结果表明从人眼中分离的原纤维蛋白微纤维的珠形态与从皮肤中分离的不同。使用新开发的 MS 前制备方法和 LC-MS/MS，我们检测到 fibrillin-1 一级结构的组织特异性区域，这些区域对蛋白水解提取具有不同的敏感性。比较组织和培养物来源的微纤维，我们发现真皮和真皮成纤维细胞来源的原纤维蛋白微纤维在珠形态和周期性方面有所不同，并且在原纤维蛋白-1蛋白水解敏感性方面也表现出区域差异。相比之下，来自相同真皮或成纤维细胞样品的 VI 型胶原蛋白微纤维在超微结构（周期性）和蛋白酶敏感性方面保持不变。最后，我们观察到皮肤和眼睛来源的微纤维悬浮液分别富含弹性纤维和基底膜相关蛋白。 LC-MS/MS 还鉴定了对原纤维蛋白微原纤维生物学可能至关重要的蛋白质（例如钙网蛋白和蛋白质二硫键异构酶），无论其组织来源如何。细胞培养物中合成的原纤维蛋白微原纤维缺乏其中一些关键蛋白（MFAP2 和-4 以及原纤维蛋白-2）。这些结果展示了这些关键细胞外基质组件的结构多样性，这可能与它们在其所在组织中的独特作用有关。
Elastic fibers comprising fibrillin microfibrils and elastin are present in many tissues, including the skin, lungs, and arteries, where they confer elasticity and resilience. Although fibrillin microfibrils play distinct and tissue-specific functional roles, it is unclear whether their ultrastructure and composition differ between elastin-rich (skin) and elastin-poor (ciliary body and zonule) organs or after in vitro synthesis by cultured cells. Here, we used atomic force microscopy, which revealed that the bead morphology of fibrillin microfibrils isolated from the human eye differs from those isolated from the skin. Using newly developed pre-MS preparation methods and LC-MS/MS, we detected tissue-specific regions of the fibrillin-1 primary structure that were differentially susceptible to proteolytic extraction. Comparing tissue- and culture-derived microfibrils, we found that dermis- and dermal fibroblast–derived fibrillin microfibrils differ in both bead morphology and periodicity and also exhibit regional differences in fibrillin-1 proteolytic susceptibility. In contrast, collagen VI microfibrils from the same dermal or fibroblast samples were invariant in ultrastructure (periodicity) and protease susceptibility. Finally, we observed that skin- and eye-derived microfibril suspensions were enriched in elastic fiber– and basement membrane–associated proteins, respectively. LC-MS/MS also identified proteins (such as calreticulin and protein-disulfide isomerase) that are potentially fundamental to fibrillin microfibril biology, regardless of their tissue source. Fibrillin microfibrils synthesized in cell culture lacked some of these key proteins (MFAP2 and -4 and fibrillin-2). These results showcase the structural diversity of these key extracellular matrix assemblies, which may relate to their distinct roles in the tissues where they reside.