ALPHA-B-CRYSTALLIN AND 27-KD HEAT-SHOCK PROTEIN ARE REGULATED BY STRESS CONDITIONS IN THE CENTRAL-NERVOUS-SYSTEM AND ACCUMULATE IN ROSENTHAL FIBERS

To understand the significance of the accumulation of alphaB-crystalli n in Rosenthal fibers within astrocytes, the expression and metabolism of alphaB-crystallin in glioma cell lines were examined under the con ditions of beat and oxidative stress. alphaB-crystallin mRNA was incre ased after both stresses, and alphaB-crystallin protein moved from a d etergent-soluble to a detergent-insoluble form In addition, Western bl otting of Alexander's disease brain homogenates revealed that the 27-k d beat shock protein (HSP27), which is related to alphaB-crystallin, a ccumulates along with alphaB-crystallin. The presence of HSP27 in Rose nthal fibers was directly demonstrated by immunohistochemistry. Our re sults suggest that astrocytes in Alexander's disease may be involved i n an as yet unknown kind of stress reaction that causes the accumulati on of alphaB-crystallin and HSP27 and results in Rosenthal fiber forma tion.