Nahar Tasmin, Gates Monte, Secret Emilie, Siaugue Jean-Michel, Fresnais Jérôme, Rotherham Michael, Fuller Heidi R, Brown Sharon J, El Haj Alicia J, Telling Neil D
School of Life Sciences, Keele University, Staffordshire, UK.
School of Life Sciences, Keele University, Staffordshire, UK; School of Medicine, Keele University, Staffordshire, UK.
Acta Biomater. 2025 Jan 24;193:215-230. doi: 10.1016/j.actbio.2024.12.057. Epub 2025 Jan 2.
The ability to control the growth and orientation of neurites over long distances has significant implications for regenerative therapies and the development of physiologically relevant brain tissue models. In this study, the forces generated on magnetic nanoparticles internalised within intracellular endosomes are used to direct the orientation of neuronal outgrowth in cell cultures. Following differentiation, neurite orientation was observed after 3 days application of magnetic forces to human neuroblastoma (SH-SY5Y) cells, and after 4 days application to rat cortical primary neurons. The direction of neurite outgrowth was quantified using a 2D Fourier transform analysis, showing agreement with the derived magnetic force vectors. Orientation control was found to be effective over areas >1cm using modest forces of ∼10 fN per endosome, apparently limited only by the local confluence of the cells. A bioinformatics analysis of protein expression in cells exposed to magnetic forces revealed changes to cell signaling and metabolic pathways resulting in enhanced carbohydrate metabolism, as well as the perturbation of processes related to cellular organisation and proliferation. Additionally, in cell culture regions where the measured force vectors converged, large (∼100 µm) SH-SY5Y neuroclusters loaded with nanoparticles were found, connected by unusually thick linear neurite fibres. This could suggest a magnetically driven enhancement of neurocluster growth, with the clusters themselves contributing to the local forces that direct outgrowth. Such structures, which have not been previously observed, could provide new insights into the development and possible enhancement of neural circuitry. STATEMENT OF SIGNIFICANCE: A magnetic force approach for directing outgrowth in neuronal cells over macroscopic areas is successfully demonstrated. Cells were incubated with magnetic nanoparticles which were sequestered into intracellular compartments. Permanent magnet arrays created local intracellular magnetic force vectors mediated via the internalized nanoparticles, which were found to precisely guide neurite orientation. Analysis of cellular protein expression suggested the mechanism for directed growth involved specific cell signaling and metabolic pathways. In addition, highly unusual straight and thick neural fibers were observed that connected large 'magnetic' spherical cell clusters. The results reported will advance nanotechnology and cell therapy for neuro-regeneration where magnetic forces could help to reconnect damaged neurons, or even build artificial neuronal architectures.
远距离控制神经突生长和方向的能力对再生疗法以及生理相关脑组织模型的开发具有重要意义。在本研究中，利用内化于细胞内吞体中的磁性纳米颗粒产生的力来指导细胞培养中神经元生长的方向。分化后，对人神经母细胞瘤（SH-SY5Y）细胞施加3天磁力后以及对大鼠皮质原代神经元施加4天磁力后观察到神经突方向。使用二维傅里叶变换分析对神经突生长方向进行量化，结果显示与导出的磁力矢量一致。发现使用每个内吞体约10 fN的适度力在大于1cm的区域内方向控制有效，显然仅受细胞局部汇合的限制。对暴露于磁力的细胞中蛋白质表达的生物信息学分析揭示了细胞信号传导和代谢途径的变化，导致碳水化合物代谢增强，以及与细胞组织和增殖相关过程的扰动。此外，在测量的力矢量汇聚的细胞培养区域中，发现了负载有纳米颗粒的大（约100 µm）SH-SY5Y神经簇，由异常粗的线性神经突纤维连接。这可能表明磁驱动增强了神经簇的生长，这些簇本身有助于引导生长的局部力。这种以前未观察到的结构可能为神经回路的发育和可能的增强提供新的见解。重要性声明：成功证明了一种在宏观区域引导神经元细胞生长的磁力方法。将细胞与磁性纳米颗粒一起孵育，这些纳米颗粒被隔离到细胞内隔室中。永磁体阵列产生通过内化纳米颗粒介导的局部细胞内磁力矢量，发现其可精确引导神经突方向。细胞蛋白质表达分析表明，定向生长的机制涉及特定的细胞信号传导和代谢途径。此外，观察到连接大型“磁性”球形细胞簇的非常不寻常的直而粗的神经纤维。所报道的结果将推动用于神经再生的纳米技术和细胞疗法的发展，其中磁力可有助于重新连接受损神经元，甚至构建人工神经元结构。
