Expression of netrin-1, slit-1 and slit-3 but not of slit-2 after cerebellar and spinal cord lesions.
To determine whether members of the Netrin-1 and Slit families and their receptors are expressed after central nervous system (CNS) injury, we performed in situ hybridization for netrin-1, slit-1, 2 and 3, and their receptors (dcc, unc5h-1, 2 and 3, robo-1, 2 and 3) 8 days, 2-3 months and 12-18 months after traumatic lesions of rat cerebellum. The expression pattern of these molecules was unchanged in axotomized Purkinje cells, whereas unc5h3 expression was upregulated in deafferented granule cells. Cells expressing slit-2 or dcc were never detected at the lesion site. By contrast, cells expressing netrin-1, slit-1 and slit-3, unc5h-1, 2 and 3, and robo-1, 2 and 3 (rig-1) could be detected at the cerebellar lesion site as soon as 8 days after injury. Expression of unc5h-2, robo-1, robo-2, slit-1 and slit-3 at the lesion site was maintained until 3 months, and up to 12-18 months for unc5h-1 and 3 and robo-3. Likewise, in the mouse spinal cord, netrin-1, slit-1 and slit-3 were also expressed at the lesion site 8 days after injury. Most of the cells expressing these mRNAs were located at the centre of the lesions, suggesting that they are macrophages/activated microglial cells (macrophagic cells) or meningeal fibroblastic cells. The macrophagic nature of most Netrin-1-positive cells and the macrophagic or fibroblastic nature of Robo-1-positive cells were corroborated by double staining. Thus, Netrin-1, Slits and their receptors may contribute to the regenerative failure of axons in the adult CNS by inhibiting axon outgrowth or by participating in the formation of the CNS scar.
Wehrle
Rosine
R
INSERM-U106/U616, Hôpital de la Salpêtrière, 75013 Paris France.
Camand
Emeline
E
Chedotal
Alain
A
Sotelo
Constantino
C
Dusart
Isabelle
I
D000818:Animals; D002531:Cerebellum / Q000293:injuries / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D000075388:Netrin-1; D051381:Rats; D017208:Rats, Wistar; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism; D013119:Spinal Cord Injuries / Q000378:metabolism*; D013997:Time Factors; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D000097905:Roundabout Proteins; D000098552:Slit Homolog 2 Protein
D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D000075388:Netrin-1; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D025521:Tumor Suppressor Proteins; D000097905:Roundabout Proteins; D000098552:Slit Homolog 2 Protein; C000617353:Ntn1 protein, mouse; C000617354:Ntn1 protein, rat; C492288:Slit1 protein, rat; C498991:Slit3 protein, rat