허혈 후 뇌신경계에서의 aB-crystallin 의 발현

초록

aB-crystallin (a-BC), known as a vertebrate lens protein, is a member of the small heat shock proteins (sHSP). a-BC is constitutively expressed in vertebrate lens as well as in non-ocular tissues including the central nervous system (CNS). Here, we systematically investigated the expression of a-BC in rat brain following middle cerebral artery occlusion (MCAO). The induction of a-BC in RNA and protein levels occurred within 1 hr after ischemia-reperfusion. a-BC was induced in the pyramidal neurons in the ischemic penumbra region of the ipsilateral side of the cerebral cortex. At 2-4 days after ischemia, a-BC immunoreactivity was induced in the reactive astrocytes restricted to peri-infarct region. Expression of a-BC in astrocytes was evidenced by double immunofluorescence staining with the glial fibrillary acidic protein (GFAP). MAPKAPK-2, one of the upstream kinase of a-BC was activated from several hours and peaked at 1 day after ischemic/reperfusion injury. Co-immunoprecipitation of p-MAPKAPK-2 with a-BC revealed the association of MAPKAPK-2 activation with a-BC induction in the post-ischemic brain. Currently, we are investigating co-localisation of p38b and a-BC in neurons and reactive astrocytes. These data suggest an important role of the induction of a-BC in neurons and reactive astrocytes in postischemic brain, which might in part be related with p38 MAPK signaling pathways.