Merryweather D, Moxon S R, Capel A J, Hooper N M, Lewis M P, Roach P
Department of Chemistry, Loughborough University Leicestershire LE11 3TU UK
Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre Manchester M13 9PL UK.
RSC Adv. 2021 Oct 7;11(52):33124-33135. doi: 10.1039/d1ra05257h. eCollection 2021 Oct 4.
Cellular metabolism and behaviour is closely linked to cytoskeletal tension and scaffold mechanics. In the developing nervous system functional connectivity is controlled by the interplay between chemical and mechanical cues that initiate programs of cell behaviour. Replication of functional connectivity in neuronal populations has proven a technical challenge due to the absence of many systems of biomechanical regulation that control directional outgrowth . Here, a 3D culture system is explored by dilution of a type I collagen hydrogel to produce variation in gel stiffness. Hydrogel scaffold remodelling was found to be linked to gel collagen concentration, with a greater degree of gel contraction occurring at lower concentrations. Gel mechanics were found to evolve over the culture period according to collagen concentration. Less concentrated gels reduced in stiffness, whilst a biphasic pattern of increasing and then decreasing stiffness was observed at higher concentrations. Analysis of these cultures by PCR revealed a program of shifting integrin expression and highly variable activity in key morphogenic signal pathways, such as mitogen-associated protein kinase, indicating genetic impact of biomaterial interactions mechano-regulation. Gel contraction at lower concentrations was also found to be accompanied by an increase in average collagen fibre diameter. Minor changes in biomaterial mechanics result in significant changes in programmed cell behaviour, resulting in adoption of markedly different cell morphologies and ability to remodel the scaffold. Advanced understanding of cell-biomaterial interactions, over short and long-term culture, is of critical importance in the development of novel tissue engineering strategies for the fabrication of biomimetic 3D neuro-tissue constructs. Simple methods of tailoring the initial mechanical environment presented to SH-SY5Y populations in 3D can lead to significantly different programs of network development over time.
细胞代谢与行为与细胞骨架张力及支架力学密切相关。在发育中的神经系统中，功能连接性由启动细胞行为程序的化学和机械信号之间的相互作用控制。由于缺乏许多控制定向生长的生物力学调节系统，在神经元群体中复制功能连接性已被证明是一项技术挑战。在此，通过稀释I型胶原蛋白水凝胶来探索一种3D培养系统，以产生凝胶硬度的变化。发现水凝胶支架重塑与凝胶胶原蛋白浓度有关，在较低浓度下会发生更大程度的凝胶收缩。发现凝胶力学在培养期间会根据胶原蛋白浓度而演变。浓度较低的凝胶硬度降低，而在较高浓度下观察到硬度先增加后降低的双相模式。通过PCR对这些培养物进行分析，揭示了整合素表达的变化程序以及关键形态发生信号通路（如丝裂原相关蛋白激酶）中高度可变的活性，表明生物材料相互作用的机械调节对基因有影响。还发现较低浓度下的凝胶收缩伴随着平均胶原纤维直径的增加。生物材料力学的微小变化会导致程序化细胞行为的显著变化，从而导致采用明显不同的细胞形态和重塑支架的能力。对短期和长期培养过程中细胞与生物材料相互作用的深入理解，对于开发用于制造仿生3D神经组织构建体的新型组织工程策略至关重要。在3D中为SH-SY5Y群体提供初始机械环境的简单方法，随着时间的推移可能会导致显著不同的网络发育程序。
