Association of dystroglycan and laminin-2 coexpression with myelinogenesis in peripheral nerves.
To provide clues to the biological functions of dystroglycan-laminin-2 complex in peripheral nerves, we investigated the expressions of beta-dystroglycan and laminin-alpha(2) chain in rat sciatic nerve during axonal degeneration and regeneration and during development, as well as in rat dorsal root ganglia. In normal conditions, immunoreactivity of the cytoplasmic domain of beta-dystroglycan was associated with the Schwann cell abaxonal membrane. The immunoreactivities of both beta-dystroglycan and the laminin-alpha(2) chain decreased in Schwann cells losing axons during axonal degeneration and progressively increased in remyelinating Schwann cells during axonal regeneration. Interestingly, during axonal degeneration, the abaxonal membrane losing contact with the basal lamina lost the association with beta-dystroglycan immunoreactivity. During development, expression of both beta-dystroglycan and laminin-alpha(2) chain strikingly increased during postnatal 7 days, which is a critical period when basal lamina assembly and myelin formation rapidly progress. These results suggest that coexpression of dystroglycan and laminin-2 is associated with myelinogenesis in peripheral nerves. These two proteins may function as an anchorage between the abaxonal membrane and the basal lamina, enabling myelin forma-tion to progress. Beta-dystroglycan and laminin-2 were also coexpressed in satellite cells in dorsal root ganglia, suggesting that interaction of these two proteins plays some role in physiological functions of these cells.
Masaki
Toshihiro
T
Department of Neurology, National Institute on Alcoholism, Kurihama National Hospital, Yokosuka, Kanagawa 239-0841, Japan.
Matsumura
Kiichiro
K
Saito
Fumiaki
F
Yamada
Hiroki
H
Higuchi
Susumu
S
Kamakura
Keiko
K
Yorifuji
Hiroshi
H
Shimizu
Teruo
T
D000818:Animals; D049030:Dystroglycans / Q000378:metabolism*; D015870:Gene Expression; D007797:Laminin / Q000378:metabolism*; D009416:Nerve Regeneration / Q000502:physiology*; D010525:Peripheral Nerves / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012583:Schwann Cells / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure
D007797:Laminin; C102645:laminin alpha 2; D049030:Dystroglycans