Low forces push the maturation of neural precursors into neurons

Abstract

Mechanical stimulation modulates neural development and neuronal activity. In a previous study, we proposed magnetic nano-pulling as a tool to generate active forces. By loading neural cells with magnetic nanoparticles (MNPs), a precise force vector is remotely generated through static magnetic fields. In the present study, human neural stem cells (NSCs) were subjected to a standard differentiation protocol, in the presence or absence of nano-pulling. Under mechanical stimulation, we found an increase in the length of the neural processes which showed an enrichment in microtubules, endoplasmic reticulum, and mitochondria. A stimulation lasting up to 52 days induced a strong remodelling at the level of synapse density and a re-organization of the neuronal network, halving the time required for the maturation of neural precursors into neurons. We then injected the MNP-loaded NSCs into mouse spinal cord slices, demonstrating that nano-pulling stimulates the elongation of the NPC processes and modulates their orientation even in an ex vivo model system. To the best of our knowledge, this is the first evidence showing that active mechanical stimuli can guide the outgrowth of NSCs transplanted into the spinal cord tissue. Our findings suggest that MNPs play an important role in neuronal maturation which could be applied in regenerative medicine.

Nano-pulling stimulates axon regeneration in dorsal root ganglia by inducing stabilization of axonal microtubules and activation of local translation

“…2C). This data on mitochondria in stretched ganglia are in line with previous finding on mice, human and chick isolated neurons (Lamoureux et al, 2010; De Vincentiis et al, 2023; Falconieri et al, 2023)…”

“…2C). This data on mitochondria in stretched ganglia are in line with previous finding on mice, human and chick isolated neurons (Lamoureux et al, 2010;De Vincentiis et al, 2023;Falconieri et al, 2023) Endoplasmic reticulum is another key component for the production of proteins required for axon regeneration. Our experimental data revealed a strong increase in ER cisternae in stretched samples compared to spontaneous regeneration (fig.…”

Long-term mouse spinal cord organotypic slice culture as a platform for validating cell transplantation in spinal cord injury

“…Apoptotic rate (% aCasp3 + cells/Total number of Hu-Nu + cells) was found to be very low (0.44±0.34 %) after 30 DPT ( Figure 5B ). Moreover, the apoptotic rate at DPT 30 was found to be in line with that one found for the same type of cells at DPT 7, reported in De Vincentiis, S. et al, 2023 , documenting that the cultures stabilize with time.…”

“…The neural stem cell graft into slices was maintained for 30 days after transplant and cells showed GFP expression for all the period in culture. The apoptotic rate of cells at day post-transplant (DPT) 30 was also found to be in line with respect to the apoptotic rate value observed at DPT 7 in the same cells ( De Vincentiis, S. et al, 2023 ). Cells seemed to engraft into the tissue environment and survived up to several weeks.…”

Engineered cell culture microenvironments for mechanobiology studies of brain neural cells

“…Arulmoli et al ( Arulmoli et al, 2015 ) found that statically stressed membranes increased the differentiation of neural stem cells and neural progenitor cells into oligodendrocytes. Magnetic manipulation, another technique to investigate the effect of stretching and resulting nano-pulling, promoted neural differentiation, axonal elongation, sprouting, and neuron maturation ( Vincentiis et al, 2022 ). In addition, Vincentiis et al ( Vincentiis et al, 2022 ) showed that the nano-pulling stimulation led to a reorganization of the neural network and remodelling at the level of synapse density, halving the required time for maturation of neural precursors into neurons.…”