The Expression, Protective Role And Mechanism Of 14-3-3 Proteins In Ischemic Neurons

14-3-3 protein family has seven mammalian isoforms:β,γ,η,ζ,τand is highlyexpressed in the brain. 14-3-3 binds to more than 200 other proteins and is known to playcritical regulatory roles in the survival and apoptosis of cells. 14 -3-3 isoforms are nowconsidered to have distinct functions in neurological diseases such as Alzheimer's disease,Parkinson's disease and Creutzfeldt-Jakob disease. We have previously reported that 14-3-3protected ischemic astrocytes from apoptosis. Here, we studied the expression and theprotective roles of 14-3-3 proteins in ischemic neurons. The expression levels of 14-3-3 geneand protein were evidently upregulated in primary culture of cerebral cortical neurons uponoxygen- and glucose-deprivation (OGD) treatment. Using immunohistochemistry, RT-PCRand Western blot analysis, the involvement of 14-3-3 proteins, Bax, -catenin and p53 inneuronal ischemic resistance was examined in rats subjected to 1 h transient global cerebralischemia followed by 24 h reperfusion injury. Compared to controlateral counterpart, 14-3-3and were selectively up-regulated in cortex and CA1 hipocummpus neurons while14-3-3ηand did not altered evidently in ipsilateral neurons. The expression of Bax,-catenin and p53 were also up-regulated in ischemic neurons. Western-blotting and PCRresults confirmed that 14-3-3 was up-regulated in ischemic cerebral cortex. Furthmore, weexamined the function of 14-3-3 proteins in N2a cells and demonstrated that overexpression14-3-3 decreased LDH release in OGD or hypoxic N2a cells, while inhibiting 14 -3-3through 14-3-3 siRNA or 14-3-3 inhibition-peptide resulted elevated cell-damage. Amongthe severn 14-3-3 isoforms:β,ε,γ,η,σ,τ,ζwe find that only 14-3-3 and isoforms coulddownregulate endogenous Bax and p53 proteins evidently. Moreover,co-immunoprecipitation demonstrated that elevated 14-3-3 bound with more p- catenin,but neither Bax nor p53. These data suggests that 14-3-3 overexpression acquires significantfunctions of neuronal protection in the injured brain through down regulate Bax and p53proteins as well as -Catenin ways, which provides a possibility to develop a novel therapeutic strategy for the patients with stroke.