Synthesis, localization and externalization of galectin-1 in mature dorsal root ganglion neurons and Schwann cells.
We recently confirmed that oxidized galectin-1 is a novel factor enhancing axonal growth in peripheral nerves after axotomy, but the process of extracellular release and oxidization of endogenous galectin-1 in the injured nervous tissue remains unknown. In the present study, we examined the distribution of galectin-1 in adult rat dorsal root ganglia (DRG) in vivo and in vitro. By RT-PCR analysis and in situ hybridization histochemistry, galectin-1 mRNA was detected in both DRG neurons and non-neuronal cells. Immunohistochemical analyses revealed that galectin-1 was distributed diffusely throughout the cytoplasm in smaller diameter neurons and Schwann cells in DRG sections. In contrast, the immunoreactivity for galectin-1 was detected in almost all DRG neurons from an early stage in culture (3 h after seeding) and was restricted to the surface and/or extracellular region of neurons and Schwann cells at later stages in culture. In a manner similar to the primary cultured cells, we also observed the surface and extracellular expression of this molecule in immortalized adult mouse Schwann cells (IMS32). Western blot analysis has revealed that both reduced and oxidized forms of galectin-1 were detected in culture media of DRG neurons and IMS32. These findings suggest that galectin-1 is externalized from DRG neurons and Schwann cells upon axonal injury. Some of the molecules in the extracellular milieu may be converted to the oxidized form, which lacks lectin activity but could act on neural tissue as a cytokine.
Sango
Kazunori
K
Department of Developmental Morphology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu-shi, Tokyo 183-8526, Japan. kazsango@tmin.ac.jp
Tokashiki
Akiko
A
Ajiki
Kyoko
K
Horie
Masao
M
Kawano
Hitoshi
H
Watabe
Kazuhiko
K
Horie
Hidenori
H
Kadoya
Toshihiko
T
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D002461:Cell Line, Transformed; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D005089:Exocytosis / Q000235:genetics; D045604:Extracellular Fluid / Q000378:metabolism; D005260:Female; D037483:Galectin 1 / Q000096:biosynthesis* / Q000235:genetics; D005727:Ganglia, Spinal / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D007150:Immunohistochemistry; D008247:Lysosomes / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D009416:Nerve Regeneration / Q000235:genetics*; D009475:Neurons, Afferent / Q000378:metabolism* / Q000648:ultrastructure; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000378:metabolism / Q000648:ultrastructure; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012583:Schwann Cells / Q000378:metabolism* / Q000648:ultrastructure
D037483:Galectin 1; D012333:RNA, Messenger