Astrocytic Alpha7 Nicotinic Receptors Inhibit β-amyloid Aggregation Via Upregulation Endogenous Cryab

Objective: To investigate that the activation of α7nAChR can inhibit β-amyloid aggregation and underlying molecular mechanisms in Alzheimer’s disease.Methods: Primary culture of rat astrocytes was prepared from the cortex and hippocampus of the brains of newborn Sprague–Dawley(SD)rats.Subculture for three or four times,the passaged cells were demonstrated purity by immunocytochemical stainings with anti–GFAP antibody.Aβ1-42 oligomer was prepared by using chemically synthetic Aβ1-42 polypeptide in vitro and then the oligomers were identified by the assay of western blotting.The experimental groups were divided into normal control group,agonist group,blocking agent group,or / and Aβ group.The expression of endogenous Cryab protein and the degradation of Aβ after activation of astrocytic α7 nAChR were detected by western blotting.Results: Astrocytes were isolated and cultured successfully,and their ratios were identified to be above 95%,then can perform the later experiment.Compared with the control group,the expression of Cryab of Nicotine group was significantly higher(P<0.05),and the group of Nicotine expression of Cryab was higher than the blocking agent group(P<0.01);cell lysis,compared with the Aβ group,the Nicotine group of expression of Aβ was significantly lower(P<0.01),and the Nicotine group of expression of Aβ was significantly lower than the blocking agent group(P<0.01).Compared with the control group,the expression of Cryab of PNU group was higher(P<0.05),and the PNU group of expression of Cryab was higher than the blocking agent group(P<0.01);cell lysis,compared with the Aβ group,the PNU group of expression of Aβ was significantly lower(P<0.01),and the PNU group of expression of Aβ was lower than the blocking agent group(P<0.01).Compared with the control group,the expression of Cryab of s24795 group was significantly higher(P<0.01),and the agonist group of expression of Cryab was significantly higher than the blocking agent group(P<0.01);cell lysis,compared with the Aβ group,the s24795 group of expression of Aβ was significantly lower(P<0.01),and the s24795 group of expression of Aβ was lower than the blocking agent group(P<0.01).Compared with the control group,the expression of P-Akt of Nicotine group was significantly higher(P<0.05),and the group of Nicotine expression of P-Akt was higher than the blocking agent group(P<0.01);Compared with the control group,the expression of P-Akt of PNU group was significantly higher(P<0.05),and the group of PNU expression of P-Akt was higher than the blocking agent group(P<0.01);Compared with the control group,the expression of P-Akt of s24795 group was significantly higher(P<0.05),and the group of s24795 expression of P-Akt was higher than the blocking agent group(P<0.01).Conclusion: With the cultural method can acquire the high purity astrocytes in vitro.these data indicated that Nicotine,PNU,S24795 can significantly inhibit Aβ aggregation via activation α7 nAChRs as well as upregulation of endogenous Cryab in astrocytes.PI3K/Akt signaling pathway is likely to be involved in this process.These results provided experimental data in the study of possible mechanism by which endogenous Cryab inhibits Aβ aggregation.