title: HSP27 is markedly induced in Schwann cell columns and associated regenerating axons.
abstract: It is well known that regenerating axons enter Schwann cell (SC) columns, within which they grow to reinnervate the appropriate targets. The current study detected a marked induction of a 27-kDa heat shock protein (HSP27) in the SC columns of crush-injured rat sciatic nerves. Immunohistochemical studies showed the first appearance of strong HSP27-immunoreactive linear structures in the proximal stump near an injury site 7 h after an operation. The HSP27-immunoreactive linear structures crossed the injury site to the distal stump 2 days after the operation. They then extended in a more proximal and more distal direction and were found to have propagated through the entire length of the nerve 1 week after the operation. This pattern of expression was maintained until 3 weeks after the operation. Double-immunofluorescent labeling and confocal laser microscopy confirmed that the linear structures consisted of SC columns and associated multiple axons. The HSP27-immunoreactive SC columns expressed glial fibrillary acidic protein, but not S-100 protein. Electron microscopy and immunoelectron microscopy demonstrated that reactive Schwann cells (SCs) and the associated axons with an outgrowing profile exhibited a strong immunoreactivity to HSP27, with the former containing a greater number of bundles of intermediate filaments. It is suggested that HSP27 may play an essential role in axonal outgrowth, especially by contributing to cytoskeletal dynamics in SCs.
authors.affiliation: Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. hirata@anat1.med.kyushu-u.ac.jp
authors.forename: Kazuho
authors.initials: K
authors.lastname: Hirata
authors.forename: Jianwen
authors.initials: J
authors.lastname: He
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hirakawa
authors.forename: Wenting
authors.initials: W
authors.lastname: Liu
authors.forename: Songyan
authors.initials: S
authors.lastname: Wang
authors.forename: Masaru
authors.initials: M
authors.lastname: Kawabuchi
mesh_terms: D000818:Animals; D001369:Axons / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D006360:Heat-Shock Proteins / Q000032:analysis / Q000096:biosynthesis*; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012583:Schwann Cells / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D020426:Sciatic Neuropathy / Q000378:metabolism
chemical_list: D006360:Heat-Shock Proteins