Markov Petar, Zhu Hanxing, Boote Craig, Blain Emma J
School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.
School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, UK.
Biochem Biophys Rep. 2022 Sep 13;32:101338. doi: 10.1016/j.bbrep.2022.101338. eCollection 2022 Dec.
Mechanical loading regulates the functional capabilities of the ocular system, particularly in the sclera ('white of the eye') - the principal load-bearing tissue of the ocular globe. Resident fibroblasts of the scleral eye wall are continuously subjected to fluctuating mechanical strains arising from eye movements, cerebrospinal fluid pressure and, most influentially, intra-ocular pressure (IOP). Whilst fibroblasts are hypothesised to actively participate in scleral biomechanics, to date limited information has been reported on how the macroscopic stresses and strains are transmitted via their cytoskeletal networks. In this study, the effect of applying either a '' (simulating healthy IOP) or a '' (simulating an elevated glaucomatous IOP) to bovine scleral fibroblasts, as a model of human glaucoma, was conducted to characterise cytoskeletal organisation, chromatin condensation and cell dimensions using immunofluorescence confocal microscopy. Quantification of cell parameters and cytoskeletal element anisotropy were subsequently performed using FibrilTool, and chromatin condensation parameter assessment through a bespoke MATLAB script. The novel findings suggest that physiological load-induced F-actin rearrangement is transient, whereas pathological load, recapitulating glaucomatous IOP levels, had a reversible and inhibitory influence on remodelling of the cytoskeletal architecture and, further, induction of chromatin condensation. Ultimately, this could compromise cell behaviour. These findings could provide valuable insight into the mechanism(s) used by scleral fibroblasts to mechanically adapt to support biomechanical tissue integrity, and how it could be potentially modified for therapeutic avenues targeting mechanically mediated ocular pathologies such as glaucoma.
机械负荷调节眼系统的功能，特别是在巩膜（“眼白”）中，巩膜是眼球的主要承重组织。巩膜眼壁中的成纤维细胞持续受到眼球运动、脑脊液压力以及最具影响力的眼内压（IOP）产生的波动机械应变的影响。虽然成纤维细胞被认为积极参与巩膜生物力学，但迄今为止，关于宏观应力和应变如何通过其细胞骨架网络传递的信息报道有限。在本研究中，以人青光眼为模型，对牛巩膜成纤维细胞施加“”（模拟健康眼内压）或“”（模拟青光眼性眼内压升高），以使用免疫荧光共聚焦显微镜表征细胞骨架组织、染色质凝聚和细胞尺寸。随后使用FibrilTool对细胞参数和细胞骨架元件各向异性进行量化，并通过定制的MATLAB脚本评估染色质凝聚参数。新发现表明，生理负荷诱导的F-肌动蛋白重排是短暂的，而模拟青光眼性眼内压水平的病理负荷对细胞骨架结构重塑具有可逆性抑制作用，并进一步诱导染色质凝聚。最终，这可能会损害细胞行为。这些发现可以为巩膜成纤维细胞用于机械适应以支持生物力学组织完整性的机制提供有价值的见解，以及如何针对青光眼等机械介导的眼部疾病的治疗途径对其进行潜在的修改。
