αB-crystallin (α-BC), the fifth member of mammalian small heat shock protein family (HspB5), is known to be expressed in many tissues and has a distinctive interaction with cytoskeleton components. In this study, we investigated that α-BC and microtubule-associated protein-2 (MAP-2), a neuron-specific cytoskeleton protein, were coexpressed in neurons of Gerbil cortex, while in subcortex Gerbil brains, we found that several MAP-2-negative glia cells also express α-BC. When subjected to 10-minute bilateral carotid artery occlusion (BCAO), an increment was observed in α-BC-positive cells after 6-hour reperfusion and peaked at around 7 days after. In the same circumstances, the number and the staining concentration of MAP-2 positive neurons significantly decreased immediately after 6-hour reperfusion, followed by a slow recovery, which is consistent with the increase of α-BC. Our results suggested that α-BC plays an important role in brain ischemia, providing the early protection of neurons by giving intracellular supports through the maintenance of cytoskeleton and extracellular supports through the protection of glia cells. 1. Introduction αB-crystallin/HspB5 (α-BC) is one member of the mammalian small heat shock protein family which consists of ten known members from HspB1 to B10. Though isolated from the crystallin lens, it has been described in a broad number of tissues and organs including the brain, skeletal muscle, heart, and kidney, and it is shown to implicate in many diseases, such as multiple sclerosis (MS), Guillain-Barre syndrome (GBS), Alexander disease, epilepsy, Down syndrome, familial amyotrophic lateral sclerosis (FALS), familial amyloidotic polyneuropathy and chronic inflammatory demyelinating polyneuropathy [1–8]. It has been reported that α-BC functions as molecular chaperones by binding with denatured protein under stress in a reversible equilibrium state. In addition, the specific interaction between α-BC and cytoskeletal structures in cardiac and skeletal myocytes has been proved, and the interaction is enhanced after stress, which contributes to increased stress tolerance [9–12]. The increased expression of α-BC in cerebral arteriovenous malformations (AVMs) is also associated with maintenance of the intermediate fibre (IF) network, which increases wall tension caused by dilating vessels and the hemodynamic stress surrounding , another research found out that α-BC significantly suppressed the ADP-induced secretions of both platelet-derived growth factor (PDGF) and serotonin by inhibition of HSP27 phosphorylation via p44/p42
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