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

EPSRC产品组合：该项目与以下EPSRC“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学，数值分析巩膜（“眼睛的白色”）保持眼睛的结构完整性和稳定的视力。巩膜生物力学由承载细胞外基质（ECM）控制，由机械敏感的成纤维细胞动态调节。虽然巩膜ECM在决定组织力学中的作用已经被广泛研究，但细胞的作用却不太清楚。鉴于巩膜力学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方面将推动新治疗方法的发展。我们提出动态巩膜生物力学行为是由缓慢（ECM重塑）和快速（细胞骨骼-ECM）成纤维细胞驱动的反应调节的，这对眼睛在多个时间尺度上承受正常和病理眼压（IOP）变化的能力至关重要，其他成纤维细胞类型，包括椎间盘、软骨细胞和成骨细胞也证明了这一点。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三维随机纤维模型的细胞骨架/ECM网络的数值框架。目前的项目将通过结合实验衍生的细胞骨架/ECM纤维取向来提取生理精确的机械性能来扩展这一研究。项目目的：通过将细胞置于模拟体内巩膜壁应力的振荡应变中，确定人巩膜成纤维细胞对IOP波动的收缩反应。用共聚焦显微镜观察模拟IOP下细胞骨架蛋白重组的特征。使用x射线散射和多光子显微镜量化巩膜ECM中的胶原纤维组织。建立数值模型，预测成纤维细胞力转导压力调节改变对人眼生物力学的影响。我们将调整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。结果：巩膜生物力学损伤是近视和青光眼的病理生理学基础，这两种视力障碍共同影响着超过17亿人。目前主要的临床兴趣是开发基于巩膜材料特性改变的干预措施。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，所提出的工作将为新型近视和青光眼治疗的未来发展提供信息和推动。具体来说，这些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.