CEPO-Fc (An EPO Derivative) Protects Hippocampus Against Aβ-induced Memory Deterioration: A Behavioral and Molecular Study in a Rat Model of Aβ Toxicity

Abstract

Alzheimer's disease (AD) is a debilitating neurodegenerative disease, characterized by extracellular deposition of senile plaques, mostly amyloid β-protein (Aβ) and neuronal loss. The neuroprotective effects of erythropoietin (EPO) have been reported in some models of neurodegenerative disease, but because of its hematopoietic side effects, its derivatives lacking hematopoietic bioactivity is recommended. In this study, the neuroprotective effects of carbamylated erythropoietin-Fc (CEPO-Fc) against beta amyloid-induced memory deficit were evaluated. Adult male Wistar rats weighing 250-300 g were bilaterally cannulated into CA1. Aβ_25-35 was administered intrahippocampally for 4 consecutive days (5 μg/2.5 μL/each side/day). CEPO-Fc (500 or 5000 IU) was injected intraperitoneally during days 4-9. Learning and memory performance of rats was assessed on days 10-13 using Morris Water Maze, then hippocampi were isolated and the amount of activated forms of hippocampal MAPKs' subfamily, Akt/GSK-3β and MMP-2 were analyzed using Western blot. From the behavioral results, it was revealed that CEPO-Fc treatment in both 500 and 5000 IU significantly reversed Aβ-induced learning and memory deterioration. From the molecular analysis, an increment of MAPKs and MMP-2 activity and an imbalance in Akt/GSK-3β signaling after Aβ_25-35 administration was observed. CEPO-Fc treatment prevented the elevation of hippocampal of P38, ERK, MMP-2 activity and also Akt/GSK-3β signaling impairment induced by Aβ_25-35 but it had no effect on JNK. It seems that CEPO-Fc prevents Aβ-induced learning and memory deterioration, and also modulates hippocampal MAPKs, Akt/GSK-3β and MMP-2 activity. This study suggests that CEPO-Fc can be considered as a potential therapeutic strategy for memory deficits like AD.

Keywords: Akt/GSK-3β; Alzheimer’s disease; CEPO-Fc; MAPKs; MMP-2.