Radix Hedysari Polysaccharide Protects PC12 Cells Against Aβ_25-35-Induced Apoptosis Via PRKCB/ERK-Dependent Pathways

Background and ObjectiveAlzheimer’s disease(AD)is an age-related neurodegenerative disease.It is characterized by memory impairment,cognitive dysfunction and behavioral disorders in clinic.With the extension of human life expectancy and the increase in the number of the elderly,AD brings a heavy financial burden to society and families,making it an urgent social problem to be solved.The Pathogenesis of AD is complex and incompletely understood,involving multiple genes and pathways.Radix Hedysari Polysaccharide(RHP),derived from the traditional Chinese medicine Radix Hedysari(RH),is the major bioactive component of RH.Studies found that RHP can attenuate Aβ-induced cell injury,and improve the cognitive and memory of AD model rats.However,the molecular mechanisms underlying the phenomenon remain unknown.Methods1.Gene expression profile(GSE36980)was downloaded from GEO database and recalculated to identify DEGs.The Pathogenesis of AD is explored by GO,KEGG-pathway,Pathway-relation-network and Gene-Signal-Network。2.Aβ-induced cell injury model was utilized as cellular model in vitro for AD in this study.3.Cell viability,apoptosis and proteins expression of p-ERK、ERK、p-P3 8、P3 8、p-JNK、JNK、PRKCB、caspase-3 were detected by MTT assay,flow cytometry and western blot respectively.4.PC 12 cells were invided into 6 groups.PRKCB signaling was blocked by inhibitor,followed by the detection of cell viability,apoptosis and proteins expression of p-ERK and ERK with MTT assay,flow cytometry and western blot respectively.5.PC12 cells were invided into 6 groups.Cell viability,apoptosis and the expression of mitochondrial pathway-related proteins of bcl-2,bax and caspase-3 were detected by MTT assay,flow cytometry and western blot respectively,after the obstruction of ERK1/2 signaling.Results1.As a result,691 DEGs were identified.Through GO annotation,we noticed that the DEGs were mainly enriched in synapse related genes,such as:synaptic transmission,transmembrane transport,neurotransmitter secretion,synaptic vesicle,synaptic vesicle membrane,etc.Then,the aberrant pathways were found to be related to MAPKs,and Calcium signaling pathway.Meanwhile,several hub genes that have strong association with AD were screened out,such as PLCB1,ITGB4,PLCE1,PRKCB and PRKCG2.Aβ25-35 can decrease cell viability and increase apoptosis of PC12 cells.3.After pretreatment with RHP,compared with AD model group,the cell viability and apoptosis of PC 12 cells in Aβ+ RHP treated group were increased and decreased respectively,and accompanied with the activation of ERK1/2 and the increase of PRKCB expression.4.After the application of PRKCB inhibitor LY333531,the results showed that PRKCB plays an important role in the protective effect of RHP on PC 12 cells.The function of PRKCB may be related to the ERK1/2 signaling pathway.5.After the application of ERK inhibitor PD98059,the results suggest that ERK1/2 signaling pathway could mediate the process of PRKCB inhibiting apoptosis of PC 12 cell by regulating the mitochondrial apoptosis pathway.ConclusionThe protective effects of RHP on Aβ25-35 induced apoptosis on PC 12 cells could be accomplished by up-regulating PRKCB expression.ERK1/2 signaling pathway may mediate the role of PRKCB in protecting PC 12 cells by regulating the mitochondrial apoptotic pathway.