Mechanical Causation of Corneal Stromal Matrix Synthesis and Fibrosis

项目摘要 角膜和巩膜是坚韧的纤维性眼膜的主要承重构件， 是一个完整的机械生物结构。在发育过程中，眼睛的形状已经被调整到 通过长时间尺度的载荷历史整合， 它最初的基因模式虽然力学是众所周知的，有助于发展的许多 在结缔组织中，眼球地球仪在扩张过程中对压力（拉伸壁应力）特别敏感 成长阶段。即使在成熟的眼被膜中，机械不稳定性也经常表现为 破坏视力（例如近视、圆锥角膜、LASIK术后扩张、牵引性视网膜脱离和青光眼）。 虽然组织结构不稳定的根本原因知之甚少，我们怀疑它们是 机械生物学的性质，并潜在地反映了存在的张力动态平衡的不平衡， 间充质细胞，它们的局部ECM和整体机械环境之间的关系。我们知道， 当成纤维细胞和它们的ECM之间的机械连接被破坏时， 眼生长的方式类似于压力损失，这表明机械通信是至关重要的， 正常的眼形态发生然而，机械力对驱动组织的机制的影响 形成和生长没有被很好地表征。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， 功能性的承重组织，在生长过程中大量扩展成宏观结构。 然而，如果我们能够发现控制组织形成和生长的新机制， 获得可以为包括纤维化在内的各种病理状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，如果我们了解了组织是如何产生的， 这将对重新设计角膜和改进再生角膜的方法产生影响， 药在拟开展的工作中，我们计划联合收割机建立人角膜基质组织细胞培养模型 用活细胞机械动力学成像进行精细化，以直接观察单个胶原分子在其 从溶液到纤维的转变。因此，我们将直接测试一个新的假设，该假设直接将本地和 在原纤维形成和生长过程中，对胶原蛋白的分子组装直接施加全局力。工作 该建议的假设是，力引起角膜基质ECM加工以调节原纤维组装， 重塑和生长。如果这个假设是正确的，那么有无数的机械机会， 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 改变了

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.