ABSTRACT
AIM:To observe the effects of neuroglobin ( NGB) overexpression on the apoptosis induced by Aβin the brains of double transgenic AD ( APPswe/PS1dE9) mice and to explore its potential mechanisms .METHODS:Twenty-four 13-month-old double transgenic AD mice were randomly divided into 3 groups:intracerebroventricular injection with normal saline (NS) group, intracerebroventricular injection with pcDNA3.1 and NS group, and intracerebroventricular injection with pcDNA3.1 and pNGB group.Immunohistochemistry was used to detect the expression of Aβ1-42 in the brains. TUNEL staining was used for analyzing the apoptosis , and the protein levels of cleaved caspase-3, caspase-9, PI3K, Akt and p-Akt were determined by Western blot .RESULTS: After intracerebroventricular injection with pNGB , the areas of Aβ1-42 in the hippocampus and cortex were decreased compared with NS group and pcDNA 3.1+NS group (P<0.01).The TUNEL-positive staining cells in the pNGB group were less than those in NS group and pcDNA 3.1 group ( P<0.01 ) . NGB overexpression attenuated the protein levels of cleaved caspase-3 and caspase-9 (P<0.01), but induced the produc-tion of PI3K and p-Akt (P<0.01).CONCLUSION:Overexpression of pNGB significantly inhibits the generation of Aβand attenuates the apoptosis induced by Aβ, indicating that NGB overexpression activates PI 3K/Akt pathway and inhibits the production of cleaved caspase-3 and caspase-9, which were tightly related with apoptosis .
ABSTRACT
AIM: To study the neuroprotective roles of neuroglobin (NGB) over-expression in the SH-SY5Y cells transfected with pAPPswe.METHODS:The plasmid pEGFP-NGB was successfully constructed and transfected into the SH-SY5Y cells, which were pretreated with pAPPswe.MTT assay was applied to detect the effect of NGB over-expres-sion on the cell survival rates.JC-1 staining was used to detect the level of mitochondrial transmembrane potential.The cell apoptosis was analyzed by flow cytometry.The effects of NGB over-expression on the protein level of p-Akt, Akt and caspase-3/9 were determined by Western blotting.The generation of Aβ42 in the cells was measured by ELISA.RE-SULTS:The cell survival rate was remarkably increased after transfection with NGB compared with control group and emp-ty plasmid group (P<0.05).The over-expression of NGB significantly inhibited the decrease in mitochondrial membrane potential induced by pAPPswe.The over-expression of NGB inhibited the apoptosis of the cells.Furthermore, over-expres-sion of NGB not only inhibited the expression of caspase-3 and caspase-9, but also induced the production of p-Akt, which was prevented by LY294002, an inhibitor of PI3K/Akt.The generation of Aβ42 was inhibited in the cells with the over-ex-pression of NGB.CONCLUSION: Over-expression of NGB significantly inhibits the SH-SY5Y cell injuries induced by pAPPswe and inhibits the expression of caspase-3/9, which is tightly related with cell apoptosis.Furthermore, the neuro-protective roles of NGB may be via activating PI3K/Akt signaling pathway.