Fibrillogenesis in dense collagen solutions: A physicochemical study
Fibrillogenesis in dense collagen solutions: A physicochemical study
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DOI：
10.1016/j.jmb.2007.12.047
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发表时间：
2008-03-07
影响因子：
5.6
通讯作者：
Belamie, E.
中科院分区：
文献类型：
--
作者：
Gobeaux, F.;Mosser, G.;Belamie, E.
原纤维形成，即胶原纤维的形成，是结缔组织形态发生的关键因素。为了了解细胞在多大程度上影响这一过程，我们系统地研究了 I 型胶原分子在体外自组装成原纤维的物理化学。我们报告称，在接近活体组织浓度（40-300 mg/ml）的高浓度范围内，I 型胶原蛋白溶液中的原纤维形成可在较宽的 pH 值和离子强度范围内产生强凝胶。通过结合显微观察（透射电子显微镜）与小角和广角 X 射线散射分析来描述凝胶的结构，并评估浓度、pH 和离子强度对原纤维尺寸和组织的影响。在 pH 6 至 pH 12 范围内的所有条件下，典型的交叉条纹图案和相应的小角 X 射线散射 67 nm 衍射峰均可见。在参考条件（pH 7.4，离子强度 = 150 mM，20 摄氏度）下，胶原蛋白浓度极大地影响所得纤维状凝胶的整体宏观结构以及纤维本身的形态和结构。在给定的胶原蛋白浓度下，将离子强度从 24 mM 增加到 261 mM 会产生更大的原纤维，直到系统变成双相。我们还表明，在胶原蛋白浓度非常高（超过 150 mg/ml）的酸性介质（pH 值类似于 2.5）中，可以形成原纤维，这表明可能存在胆甾型到近晶型相变。这组数据展示了简单的物理化学参数如何决定胶原蛋白的分子组织。这种体外模型使我们能够在分子堆积条件接近生物组织形态发生的条件下研究纤维形成的复杂过程。 (c) 2007 Elsevier Ltd. 保留所有权利。
Fibrillogenesis, the formation of collagen fibrils, is a key factor in connective tissue morphogenesis. To understand to what extent cells influence this process, we systematically studied the physicochemistry of the self-assembly of type I collagen molecules into fibrils in vitro. We report that fibrillogenesis in solutions of type I collagen, in a high concentration range close to that of living tissues (40-300 mg/ml), yields strong gels over wide pH and ionic strength ranges. Structures of gels were described by combining microscopic observations (transmission electron microscopy) with small- and wide-angle X-ray scattering analysis, and the influence of concentration, pH, and ionic strength on the fibril size and organization was evaluated. The typical cross-striated pattern and the corresponding small-angle X-ray scattering 67-nm diffraction peaks were visible in all conditions in the pH 6 to pH 12 range. In reference conditions (pH 7.4, ionic strength = 150 mM, 20 degrees C), collagen concentration greatly influences the overall macroscopic structure of the resultant fibrillar gels, as well as the morphology and structure of the fibrils themselves. At a given collagen concentration, increasing the ionic strength from 24 to 261 mM produces larger fibrils until the system becomes biphasic. We also show that fibrils can form in acidic medium (pH similar to 2.5) at very high collagen concentrations, beyond 150 mg/ml, which suggests a possible cholesteric-to-smectic phase transition. This set of data demonstrates how simple physicochemical parameters determine the molecular organization of collagen. Such an in vitro model allows us to study the intricate process of fibrillogenesis in conditions of molecular packing close to that which occurs in biological tissue morphogenesis. (c) 2007 Elsevier Ltd. All rights reserved.