Discussion: Growth Hormone Therapy Accelerates Axonal Regeneration, Promotes Motor Reinnervation, and Reduces Muscle Atrophy following Peripheral Nerve Injury

Regeneration of sciatic nerves by transplanted microvesicles of human neural stem cells derived from embryonic stem cells

Injured nerves cannot regenerate on their own, and a lack of engraftable human nerves has been a major obstacle in cell-based therapies for regenerating damaged nerves. A monolayer culture approach to obtain adherent neural stem cells from human embryonic stem cells (hESC-NSCs) was established, and the greatest number of stemness characteristics were achieved by the eighth generation of hESC-NSCs (P8 hESC-NSCs). To overcome deficits in cell therapy, we used microvesicles secreted from P8 hESC-NSCs (hESC-NSC-MVs) instead of entire hESC-NSCs. To investigate the therapeutic efficacy of hESC-NSC-MVs in vitro, hESC-NSC-MVs were cocultured with dorsal root ganglia to determine the length of axons. In vivo, we transected the sciatic nerve in SD rats and created a 5-mm gap. A sciatic nerve defect was bridged using a silicone tube filled with hESC-NSC-MVs (45 μg) in the MVs group, P8 hESC-NSCs (1 × 106 single cells) in the cell group and PBS in the control group. The hESC-NSC-MVs group showed better morphological recovery and a significantly greater number of regenerated axons than the hESC-NSCs group 12 weeks after nerve injury. These results indicated that the hESC-NSC-MVs group had the greatest ability to repair and reconstruct nerve structure and function. As a result, hESC-NSC-MVs may have potential for applications in the field of nerve regenerative repair.

The Whole Transcriptome Involved in Denervated Muscle Atrophy Following Peripheral Nerve Injury

Peripheral nerve injury (PNI) usually leads to progressive muscle atrophy and poor functional recovery. Previous studies have demonstrated that non-coding ribonucleic acid (ncRNA) is a key regulator of muscle atrophy and beneficial for the treatment of PNI. We aimed to analyze the whole transcriptome involved in denervated muscle atrophy after PNI. Animal models of sciatic nerve injury were assessed at 0 (control group), 1, 2, 4, and 8 weeks after injury. The expression patterns in the whole transcriptome in the gastrocnemius muscle were profiled using RNA sequencing at each time point and compared to that obtained in the control group. Six-hundred and sixty-four long non-coding RNAs, 671 microRNAs, 236 circular RNAs, and 12,768 messenger RNAs (mRNAs) were differentially expressed (DE) after injury. Changes in some of the DE ncRNAs and mRNAs were validated using quantitative polymerase chain reaction. Gene Ontology and Kyoko Encyclopedia of Genes and Genomes analysis revealed the potential functions of and relationships among the DE ncRNAs and mRNAs. To our knowledge, this is the first study to expound the whole transcriptome involved in denervated muscle atrophy, and provides a theoretical basis for further research targeting ncRNAs.