title: Activation of JAK/STAT signalling in neurons following spinal cord injury in mice.
abstract: The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling pathway is one of the most important in transducing signals from the cell surface to the nucleus in response to cytokines. In the present study, we investigated chronological alteration and cellular location of JAK1, STAT3, phosphorylated (p)-Tyr1022/1023-JAK1, p-Tyr705-STAT3, and interleukin-6 (IL-6) following spinal cord injury (SCI) in mice. Western blot analysis showed JAK1 to be significantly phosphorylated at Tyr1022/1023 from 6 h after SCI, peaking at 12 h and gradually decreasing thereafter, accompanied by phosphorylation of STAT3 at Tyr705 with a similar time course. ELISA analysis showed the concentration of IL-6 in injured spinal cord to also significantly increase from 3 h after SCI, peaking at 12 h, then gradually decreasing. Immunohistochemistry revealed p-Tyr1022/1023-JAK1, p-Tyr705-STAT3, and IL-6 to be mainly expressed in neurons of the anterior horns at 12 h after SCI. Pretreatment with a JAK inhibitor, AG-490, suppressed phosphorylation of JAK1 and STAT3 at 12 h after SCI, reducing recovery of motor functions. These findings suggest that SCI at the acute stage produces IL-6 mainly in neurons of the injured spinal cord, which activates the JAK/STAT pathway, and that this pathway may be involved with neuronal response to SCI.
authors.affiliation: Department of Neurosurgery, Nagoya University, Graduate School of Medicine, Nagoya, Japan.
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Koji
authors.initials: K
authors.lastname: Osuka
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takayasu
authors.forename: Nobuteru
authors.initials: N
authors.lastname: Usuda
authors.forename: Ayami
authors.initials: A
authors.lastname: Nakazawa
authors.forename: Norimoto
authors.initials: N
authors.lastname: Nakahara
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yoshida
authors.forename: Chihiro
authors.initials: C
authors.lastname: Aoshima
authors.forename: Masahito
authors.initials: M
authors.lastname: Hara
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D053613:Janus Kinase 1; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D050796:STAT3 Transcription Factor; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; D011505:Protein-Tyrosine Kinases; C507905:Jak1 protein, mouse; D053613:Janus Kinase 1; D004121:Dimethyl Sulfoxide