Neurons derived from transplanted neural stem cells restore disrupted neuronal circuitry in a mouse model of spinal cord injury
Masahiko Abematsu, Keita Tsujimura, Mariko Yamano, Michiko Saito, Kenji Kohno, Jun Kohyama, Masakazu Namihira, Setsuro Komiya, Kinichi Nakashima
Masahiko Abematsu, Keita Tsujimura, Mariko Yamano, Michiko Saito, Kenji Kohno, Jun Kohyama, Masakazu Namihira, Setsuro Komiya, Kinichi Nakashima
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Research Article

Neurons derived from transplanted neural stem cells restore disrupted neuronal circuitry in a mouse model of spinal cord injury

Abstract

The body’s capacity to restore damaged neural networks in the injured CNS is severely limited. Although various treatment regimens can partially alleviate spinal cord injury (SCI), the mechanisms responsible for symptomatic improvement remain elusive. Here, using a mouse model of SCI, we have shown that transplantation of neural stem cells (NSCs) together with administration of valproic acid (VPA), a known antiepileptic and histone deacetylase inhibitor, dramatically enhanced the restoration of hind limb function. VPA treatment promoted the differentiation of transplanted NSCs into neurons rather than glial cells. Transsynaptic anterograde corticospinal tract tracing revealed that transplant-derived neurons reconstructed broken neuronal circuits, and electron microscopic analysis revealed that the transplant-derived neurons both received and sent synaptic connections to endogenous neurons. Ablation of the transplanted cells abolished the recovery of hind limb motor function, confirming that NSC transplantation directly contributed to restored motor function. These findings raise the possibility that epigenetic status in transplanted NSCs can be manipulated to provide effective treatment for SCI.

Authors

Masahiko Abematsu, Keita Tsujimura, Mariko Yamano, Michiko Saito, Kenji Kohno, Jun Kohyama, Masakazu Namihira, Setsuro Komiya, Kinichi Nakashima

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Figure 5

Transplant-derived neurons make synapses with endogenous neurons.

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Transplant-derived neurons make synapses with endogenous neurons. (A) Im...
(A) Immunoelectron microscopy image of a sagittal section of dual-treated (GFP-NSC and VPA) injured spinal cord (rostral area). A GFP-positive dendrite (Den) made synapses with GFP-negative endogenous axon termini (At) (yellow arrowheads). Scale bar: 1 μm. (B) In other rostral regions, a dendrite of a GFP-positive transplant-derived neuron made a synapse (yellow arrowheads) with the axon terminus of a GFP-negative endogenous neuron. Scale bar: 1 μm. (C) Sagittal section of dual-treated (NSC and VPA) injured spinal cord (caudal area) stained with anti-GFP antibody (dark brown). The epicenter of the SCI is indicated (*). Scale bar: 500 μm. (D) High-magnification image of a large neuron localized in the ventral horn in the white rectangle in C. GFP-positive transplanted neurons extended their processes toward an endogenous neuron (yellow arrowheads). Scale bar: 100 μm. (E) Immunoelectron microscopy image of the boxed area in D. GFP-positive axon termini made synapses with the dendrite of a GFP-negative endogenous large neuron (yellow arrowheads). Scale bar: 1 μm.