Modeling Collagen-Proteoglycan Structural Interactions in the Human Cornea
Modeling Collagen-Proteoglycan Structural Interactions in the Human Cornea
复制标题
模拟人角膜中胶原蛋白-蛋白聚糖结构相互作用
DOI：
10.1007/978-94-007-5464-5_2
复制
发表时间：
2013
影响因子：
2
通讯作者：
P. Pinsky
中科院分区：
文献类型：
--
作者：
Xi Cheng;H. Hatami;P. Pinsky
角膜是一个高度组织的结缔组织，这使它成为建模和探索细胞外基质中胶原-PG相互作用的理想对象。角膜可以看作是一种增强的电解质凝胶，涉及胶原纤维、蛋白多糖(PG)和纤维间隙中的可移动离子之间的分子尺度相互作用。Donnan渗透压理论不能很好地预测组织的膨胀特性。我们提出了一种基于热力学框架的替代单胞方法，该方法对静电自由能采用平均场近似，并考虑了非均匀静电势。模型表明，当考虑胶原纤维体积引起的电解质排斥的几何效应时，平衡溶胀压力可以得到解释。通过将PG划分为胶原原纤维涂层和体积分区，进一步完善了模型。该模型表明，PG涂层在低水合时重叠，并建立排斥力，可能起到维持胶原晶格秩序的作用。最后，我们引入了一个分子水平的单胞，其中单胞内的体积结构域与大分子GaG相关联，并将连续统模型和分子水平模型的结果进行了比较。
The cornea is a supremely organized connective tissue making it ideal for modeling and probing possible roles of collagen-PG interactions in the extracellular matrix. The cornea can be viewed as a reinforced electrolyte gel involving molecular-scale interactions between collagen fibrils, proteoglycans (PGs) and the mobile ions in the interfibrillar space. The swelling property of the tissue cannot be adequately predicted by Donnan theory for osmotic pressure. We propose an alternative unit cell approach based on a thermodynamic framework that employs a mean-field approximation for the electrostatic free energy and which accounts for a non-uniform electrostatic potential. The model is used to show that the equilibrium swelling pressure can be explained when the geometrical effect of electrolyte exclusion due to collagen fibril volume is considered. The model is further refined by dividing the PGs into collagen fibril coating and volumetric partitions. The model suggests that the PG coatings overlap at low hydration and set up repulsive forces that may act to maintain the collagen lattice order. Finally, we introduce a molecular-level unit cell in which volumetric domains within the unit cell are associated with the macromolecular GAGs and results from the continuum and molecular-level models are compared.