Activation of extracellular signal-regulated kinases in the sciatic nerves of rats with experimental autoimmune neuritis.
To investigate whether the phosphorylation of extracellular signal-regulated kinase (ERK) is involved in autoimmune injury of the peripheral nervous system (PNS), the expression of phosphorylated ERK (p-ERK) was analyzed in experimental autoimmune neuritis (EAN) in rats. Western blot analysis showed that the level of p-ERK was increased significantly in the sciatic nerves of rats on days 14 (p<0.05) and 24 (p<0.01) post-immunization, compared with controls, and its reaction declined at day 30 post-immunization. Immunohistochemistry showed that p-ERK protein was weakly expressed in Schwann cells and vascular endothelial cells in the sciatic nerves of CFA-immunized control rats. In EAN-affected sciatic nerves, p-ERK immunoreactivity was found mainly in ED1-positive macrophages on days 14 and 24 post-immunization. Moreover, on days 24 and 30 post-immunization, p-ERK immunoreactivity increased gradually in the Schwann cells of rat sciatic nerves with EAN. Based on these results, we postulated that the phosphorylation of ERK has an important role in the differentiation and survival of cells, including inflammatory cells and Schwann cells, in the rat sciatic nerve in EAN. Specifically, the activation of ERK in the recovery phase of EAN paralysis seems to be related in the survival of Schwann cells.
Ahn
Meejung
M
Department of Veterinary Medicine, Cheju National University, Aradong 1, Jeju 690-756, South Korea.
Moon
Changjong
C
Lee
Yongduk
Y
Koh
Chang Sung
CS
Kohyama
Kuniko
K
Tanuma
Naoyuki
N
Matsumoto
Yoh
Y
Kim
Hyung-Min
HM
Kim
Seung-Ryul
SR
Shin
Taekyun
T
D000818:Animals; D004789:Enzyme Activation / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000276:immunology / Q000378:metabolism*; D005260:Female; D009444:Neuritis, Autoimmune, Experimental / Q000201:enzymology* / Q000276:immunology; D051381:Rats; D011917:Rats, Inbred Lew; D012584:Sciatic Nerve / Q000201:enzymology* / Q000276:immunology
D048049:Extracellular Signal-Regulated MAP Kinases