Mechanical Causation of Corneal Stromal Matrix Synthesis and Fibrosis

项目摘要 角膜和巩膜是我们认为的坚韧的纤维眼衣的主要承重部件。 成为一个完整的机械-生物结构。在发育过程中，眼睛的形状已经调整到 通过将加载历史与特定机械环境进行长期集成来符合特定的机械环境 它最初的遗传模式。尽管众所周知，力学对许多 结缔组织，眼球在扩张过程中对压力(张力壁应力)特别敏感 生长阶段。即使在成熟的眼球外衣中，机械不稳定性也常常表现为 视力障碍(如近视、圆锥角膜、LASIK术后扩张、牵拉性视网膜脱离和青光眼)。 虽然组织结构不稳定的根本原因还知之甚少，但我们怀疑它们是 本质上是机械生物学的，潜在地反映了存在的张力性内稳态的不平衡 间充质细胞、其局部细胞外基质和全球机械环境之间的关系。我们知道在这个过程中 成纤维细胞与其细胞外基质之间机械连接的发育、破坏严重迟缓 眼球生长的方式类似于压力损失，这表明机械沟通对 适当的眼睛形态发生。然而，机械力对驱动组织的机制的影响 形成和生长没有得到很好的描述。值得注意的是，我们仍然没有完全理解 脊椎动物中最重要的结构分子，胶原蛋白，被有效地组装成高度组织化的， 在生长过程中大量膨胀成大尺度结构的功能性、承重性组织。 然而，如果我们能够发现控制组织形成和生长的新机制，我们将拥有 获取可以为包括纤维化在内的各种病理情况的治疗提供信息的信息， 近视、圆锥角膜和潜在的青光眼。此外，如果我们了解组织是如何产生的，那么 这将对设计新的角膜工程和改进再生角膜的方法产生影响。 医药。在这项拟议的工作中，我们计划将我们的人类角膜基质组织细胞培养模型 用活细胞力学成像直接观察单个胶原分子在其 从溶液到原纤维的过渡。因此，我们将直接测试一个新的假设，它直接将本地和 在纤维形成和生长过程中，全球施加力直接作用于胶原的分子组装。在工作中 这一提议的假设是，力导致角膜基质ECM精化来调节纤维组装， 重塑和成长。如果假设是正确的，那么有无数的机械治疗机会和 更重要的是，我们对胶原组织形成和生长的基本理解，将从根本上 被更改了。

Project Summary The cornea and sclera are the principal load bearing members in the tough fibrous ocular tunic which we consider to be an integrated mechano-biological structure. During development, the shape of the eye has been tuned to conform to a specific mechanical environment through a long time-scale integration of its loading history with its initial genetic patterning. Although mechanics are known to contribute to the development of many connective tissues, the ocular globe is particularly sensitive to pressure (tensile wall stress) during the expansive phase of growth. Even in the mature ocular tunic, mechanical instabilities often manifest as conditions which disrupt vision (e.g. myopia, keratoconus, post-LASIK ectasia, tractional retinal detachments and glaucoma). While the underlying causes of tissue structural instabilities are poorly understood, we suspect that they are mechanobiological in nature and potentially reflect an imbalance in the tensional homeostasis that exists between mesenchymal cells, their local ECM and the global mechanical environment. We know that during development, disruption of the mechanical connection between fibroblastic cells and their ECM severely retards ocular growth in a manner analogous to pressure loss, suggesting that mechanical communication is critical to proper ocular morphogenesis. However, the effect of mechanical forces on the mechanisms which drive tissue formation and growth are not well characterized. It is remarkable that we still do not fully understand how the most important structural molecule in vertebrates, collagen, is efficiently assembled into highly-organized, functional, load-bearing tissues which are massively expanded into macroscale structures during growth. However, if we are able to uncover new mechanisms which control tissue formation and growth, we will have access to information which can inform therapies for a variety of pathological conditions including fibrosis, myopia, keratoconus and potentially, glaucoma. Additionally, if we understand how tissue is produced, then there will be implications for engineering corneas de novo and for improving approaches to regenerative corneal medicine. In the proposed work, we plan combine our human cell culture model of corneal stromal tissue elaboration with live-cell mechanodynamics imaging to directly observe single collagen molecules during their transition from solution to fibrils. We will thus directly test a new hypothesis which directly couples local and globally applied forces directly to molecular assembly of collagen during fibrillogenesis and growth. The working hypothesis for this proposal is that force causes corneal stromal ECM elaboration to regulate fibril assembly, remodeling and growth. If the hypothesis is correct, there are myriad mechanotherapeutic opportunities and more critically, our basic understanding of collagenous tissue formation and growth, will be fundamentally altered.