Expression of the alpha 2-macroglobulin-encoding gene in rat brain and cultured astrocytes.
The alpha 2-macroglobulin (alpha 2M), a protease inhibitor, is a major acute-phase protein in rats, and is produced in the liver during acute inflammation. Recently, it has been demonstrated that alpha 2M is also produced by cultured astrocytes from newborn rat brain and has neurite-promoting activity. Here, we found that the expression of the alpha 2M gene was significantly enhanced in the brain following intraperitoneal injection of the neurotoxicant, kainic acid (KA), suggesting that alpha 2M acts as an acute-phase protein in the brain, as in the case of the liver, and may be involved in neural repair processes. Expression of alpha 2M in cultured astrocytes was shown to be stimulated by interleukin-6 (IL-6) and/or leukemia inhibitory factor (LIF) in the presence of glucocorticoid. The amount of mRNAs for IL-6 and LIF increased in the brain of KA-injected rats prior to alpha 2M induction. These results strongly suggested that IL-6 and LIF are involved in alpha 2M induction in the brain, as in the case of the liver. Analysis of the cis-acting element(s) and the trans-acting factor(s) suggested that the regulatory mechanism for alpha 2M expression in astrocytes was similar to that in inflamed liver.
Higuchi
M
M
Laboratory for Molecular Medicine, University of Tokyo, Japan.
Ito
T
T
Imai
Y
Y
Iwaki
T
T
Hattori
M
M
Kohsaka
S
S
Niho
Y
Y
Sakaki
Y
Y
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001345:Autoradiography; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism*; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006131:Growth Inhibitors / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000494:pharmacology; D008297:Male; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D000511:alpha-Macroglobulins / Q000235:genetics*
D006131:Growth Inhibitors; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D000511:alpha-Macroglobulins; D007608:Kainic Acid