title: The cell neural adhesion molecule contactin-2 (TAG-1) is beneficial for functional recovery after spinal cord injury in adult zebrafish.
abstract: The cell neural adhesion molecule contactin-2 plays a key role in axon extension and guidance, fasciculation, and myelination during development. We thus asked, whether contactin-2 is also important in nervous system regeneration after trauma. In this study, we used an adult zebrafish spinal cord transection model to test the functions of contactin-2 in spinal cord regeneration. The expression patterns of contactin-2 at different time points after spinal cord injury were studied at the mRNA level by qPCR and in situ hybridization, and contactin-2 protein levels and immunohistological localization were detected by Western blot and immunofluorescence analyses, respectively. Contactin-2 mRNA and protein levels were increased along the central canal at 6 days and 11 days after spinal cord injury, suggesting a requirement for contactin-2 in spinal cord regeneration. Co-localization of contactin-2 and islet-1 (a motoneuron marker) was observed in spinal cords before and after injury. To further explore the functions of contactin-2 in regeneration, an anti-sense morpholino was used to knock down the expression of contactin-2 protein by application at the time of injury. Motion analysis showed that inhibition of contactin-2 retarded the recovery of swimming functions when compared to standard control morpholino. Anterograde and retrograde tracing at 6 weeks after injury showed that knock down of contactin-2 inhibited axonal regrowth from NMLF neurons beyond lesion site. The combined observations indicate that contactin-2 contributes to locomotor recovery and successful regrowth of axons after spinal cord injury in adult zebrafish.
authors.affiliation: Center for Neuroscience, Shantou University Medical College, Shantou, People's Republic of China.
authors.forename: Jin-Fei
authors.initials: JF
authors.lastname: Lin
authors.forename: Hong-Chao
authors.initials: HC
authors.lastname: Pan
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Ma
authors.forename: Yan-Qin
authors.initials: YQ
authors.lastname: Shen
authors.forename: Melitta
authors.initials: M
authors.lastname: Schachner
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001369:Axons / Q000378:metabolism / Q000473:pathology; D058969:Contactin 2 / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D008124:Locomotion; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020127:Recovery of Function; D013119:Spinal Cord Injuries / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors; D015854:Up-Regulation / Q000235:genetics; D015027:Zebrafish / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000378:metabolism*
chemical_list: D058969:Contactin 2; D012333:RNA, Messenger; D029961:Zebrafish Proteins; C581553:cntn2 protein, zebrafish