Locomotor Training Increases Synaptic Structure With High NGL-2 Expression After Spinal Cord Hemisection. (March 2019)

• Record Type: Journal Article
• Authors: Kobayakawa, Kazu; DePetro, Kyleigh Alexis; Zhong, Hui; Pham, Bau; Hara, Masamitsu; Harada, Akihito; Nogami, Jumpei; Ohkawa, Yasuyuki; Edgerton, V. Reggie
• Is Part Of: Neurorehabilitation & neural repair. Volume 33:Number 3(2019)
• Page Start: 225
• Page End: 231
• Publication Date: 2019-03
• Subjects: spinal cord injury -- hemisection -- treadmill training -- RNA-Seq; Nervous system -- Diseases -- Patients -- Rehabilitation -- Periodicals; Brain damage -- Patients -- Rehabilitation -- Periodicals; Spinal cord -- Wounds and injuries -- Patients -- Rehabilitation -- Periodicals; Nervous system -- Regeneration -- Periodicals; Neuroplasticity -- Periodicals; 616.804305
• DOI: 10.1177/1545968319829456
• Languages: English
• ISSNs: 1545-9683

Abstract

Background . We previously demonstrated that step training leads to reorganization of neuronal networks in the lumbar spinal cord of rodents after a hemisection (HX) injury and step training, including increases excitability of spinally evoked potentials in hindlimb motor neurons. Methods . In this study, we investigated changes in RNA expression and synapse number using RNA-Seq and immunohistochemistry of the lumbar spinal cord 23 days after a mid-thoracic HX in rats with and without post-HX step training. Results . Gene Ontology (GO) term clustering demonstrated that expression levels of 36 synapse-related genes were increased in trained compared with nontrained rats. Many synaptic genes were upregulated in trained rats, but Lrrc4 (coding NGL-2) was the most highly expressed in the lumbar spinal cord caudal to the HX lesion. Trained rats also had a higher number of NGL-2/synaptophysin synaptic puncta in the lumbar ventral horn. Conclusions . Our findings demonstrate clear activity-dependent regulation of synapse-related gene expression post-HX. This effect is consistent with the concept that activity-dependent phenomena can provide a mechanistic drive for epigenetic neuronal group selection in the shaping of the reorganization of synaptic networks to learn the locomotion task being trained after spinal cord injury.