Gaining Cellular Control of Ocular Biomechanics - A Potential Route to the Treatment of Eye Disease

EPSRC产品组合：该项目与EPSRC的以下“维护”领域保持一致：-生物材料与组织工程、生物物理学与软物质物理、数值分析巩膜(“眼白”)维护眼睛的结构完整性和稳定的视力。巩膜生物力学由承重的细胞外基质(ECM)控制，并由机械敏感的成纤维细胞动态调节。虽然巩膜外基质在确定组织力学中的作用已经被广泛研究，但细胞的作用还不是很清楚。鉴于巩膜机械损伤是导致视力障碍的几个主要原因[8-10]，更好地了解巩膜生物力学的细胞学方面将推动新疗法的发展。我们提出，动态巩膜生物力学行为由缓慢(细胞外基质重塑)和快速(细胞骨架-细胞外基质)成纤维细胞驱动的反应调节，这对眼睛承受多个时间尺度上正常和病理变化的眼压(IOP)的能力至关重要，正如在其他成纤维细胞类型，包括椎间盘、软骨细胞和成骨细胞中所证明的那样。我们的初步研究表明，巩膜成纤维细胞的机械负荷刺激细胞增殖并改变细胞骨架组织。我们最近开发了一个基于集成的3D随机纤维模型的细胞骨架/细胞外基质网络的数值框架。目前的项目将通过结合实验获得的细胞骨架/细胞外基质纤维取向来扩展这一点，以提取生理上准确的力学特性。该项目的目的：1.通过使细胞受到模拟巩膜壁应力的振荡应变，来确定人巩膜成纤维细胞对眼压波动的收缩反应。利用共聚焦显微镜观察细胞骨架蛋白在模拟眼压下的重组情况。用X射线散射和多光子显微镜对巩膜ECM中的胶原纤维组织进行定量。建立数值模型来预测成纤维细胞力传导中压力调节变化对人眼生物力学的影响。我们将调整我们的细胞骨架网络的随机纤维模型(图3)(AIM 2数据)，并将其与巩膜的代表性ECM纤维模型(AIM 3数据)相结合。使用青光眼实验小鼠模型，研究体内病理性眼压升高对目标1-4结果的影响结果：巩膜生物力学妥协是近视和青光眼的病理生理基础，这两种视力障碍总共影响超过17亿人。目前主要的临床兴趣是开发基于巩膜材料特性的干预措施。然而，临床终点的实现将依赖于对巩膜生物力学功能的基本科学理解。因此，拟议的工作将为近视和青光眼新疗法的未来发展提供信息和推动。具体地说，研究结果将有助于确定关键的细胞机械转导途径，这些途径可能会被修改以控制眼睛的生物力学行为。

EPSRC Portfolio: The project aligns with following EPSRC 'maintain' areas: - Biomaterials & Tissue Engineering, Biophysics & Soft Matter Physics, Numerical AnalysisThe sclera ('white of the eye') maintains the eye's structural integrity and stable vision. Scleral biomechanics are governed by the load-bearing extracellular matrix (ECM), with dynamic modulation by mechano-sensitive fibroblasts. While the role of the scleral ECM in determining tissue mechanics has been extensively researched, cellular contributions are less well-understood. Given scleral mechanical compromise underpins several leading causes of visual impairment [8-10], a better understanding of cellular aspects of scleral biomechanics will drive development of new treatments.We propose dynamic scleral biomechanical behaviour is modulated by slow (ECM remodelling) and rapid (cytoskeletal-ECM) fibroblast-driven responses, critical to the eye's ability to withstand normal and pathological variations in intraocular pressure (IOP) over multiple time-scales, as evidenced in other fibroblastic cell types, including intervertebral disc, chondrocytes and osteoblasts. Our pilot studies showed mechanical loading of scleral fibroblasts stimulates cell proliferation and alters cytoskeletal organisation. We recently developed a numerical framework for cytoskeletal/ECM networks based on an integrated 3D random fibre model. The current project will extend this by incorporating experimentally-derived cytoskeletal/ECM fibre orientations to extract physiologically-accurate mechanical properties.Aims of the project:1. Determine contractile response of human scleral fibroblasts to IOP fluctuations by subjecting cells to oscillating strains simulating scleral wall stress in-vivo.2. Characterise cytoskeletal protein re-organisation under simulated IOP using confocal microscopy.3. Quantify collagen fibre organisation in scleral ECM using x-ray scattering and multiphoton microscopy.4. Build numerical models to predict impact of pressure-regulated alterations in fibroblast force transduction on human eye biomechanics. We will adapt our random fibre models (Fig. 3) of cytoskeletal network (Aim 2 data), and integrate this with a representative ECM fibre model for the sclera (Aim 3 data).5. Investigate effect of in-vivo pathological increases in IOP on Aim 1-4 outcomes using an experimental mouse model of glaucomaOutcome: Scleral biomechanical compromise underpins the pathophysiology of myopia and glaucoma, vision disorders that collectively affect over 1.7 billion people. There is currently major clinical interest in developing interventions based on modification of scleral material properties. However attainment of clinical endpoints will rely on fundamental scientific understanding of scleral biomechanical function. Thus, the proposed work will inform and drive the future development of novel myopia and glaucoma therapies. Specifically, the outcomes will help identify key cell mechano-transduction pathways that can potentially be modified to control the eye's biomechanical behaviour.