The Role Of Nupr1 And C/EBP? In Methamphetamine-induced Neurotoxicity

BackgroundMethamphetamine(METH),also known as amphedroxyn,belongs to Amphetamine-Typed Stimulant(ATS).Attributing to it relatively simple production and processing,lower costly of abuse and strong central nervous system stimulant,it has been the most commonly used drug in the world.METH abuse brings about a series of social and legal problems such as violence and disease.Therefore,the study of molecular mechanism of METH toxicity has become the hotspot in recent years.METH-induced neurotoxicity is particularly prominent,and our previous studies have showed that METH-induced neuronal cells apoptosis through oxidative stress signal pathway.Based on the previous studies,our recent results showed that METH exposure can upregulate endoplasmic reticulum stress related marker protein in neuronal cells.Meanwhile,Nuprl and C/EBPP genes obtained by chip expression profiling expressed significantly higher than control group.However,the role of Nuprl and C/EBP? in METH-induced neurotoxicity and the detailed mechanism underlying METH-induced neuronal apoptosis and autophagy remain to be investigated.AimThe objective of our present study was to investigate the molecular mechanism in METH-induced apoptosis and autophagy in neuronal cells by focusing on the role of Nuprl and C/EBPP in this process,further providing a theoretical basis for the study of mechanism of METH-induced neurotoxicity.MethodsIn this study,we have constructed METH-exposure model in vivo and in vitro,then,we use several interference means,e.g.specific inhibitors,RNAi,to specific interfere Nuprl and C/EBPP,and use Q-PCR,Western Blot,flow cytometry,TUNEL staining,immunofluorescence and transmission electron microscopy to detect whether Nuprl and C/EBP? are invovled in METH-induced neurotoxicity.Meanwhile,we also detect Nuprl-and C/EBP?-related downstream molecular or marker protein in METH-induced neuronal apoptosis and autophagy before and after METH-exposure.ResultsPART1:(1)METH exposure induced Nuprl,apoptosis-and autophagy-marker protein,and the expression of endoplasmic reticulum stress marker protein CHOP and Trib3 in vitro and in vivo;(2)Silencing of Nuprl expression can partially attenuates METH-induced apoptosis and autophagy in vitro and in vivo;(3)Nuprl was involved in METH-induced apoptosis and autophagy in dopaminergic neurons:On one hand,Nuprl can through CHOP-mediated METH-induced apoptosis in neuronal cells,on the other hand,Nuprl can through CHOP-Trib3-mediated endoplasmic reticulum stress signaling pathway involved in METH induced neuronal autophagy.PART2:(1)METH exposure induced C/EBP?,apoptosis-and autophagy-marker protein in vitro and in vivo;(2)Silencing of C/EBP? can partially attenuates METH-induced apoptosis and autophagy in vitro and in vivo;(3)C/EBP? was involved in METH-induced apoptosis and autophagy in neuronal cells:On one hand,C/EBP? up-regulates the expression level of IGFBP5 by transactivating its promoter,and then IGFBP5 triggers mitochondra-mediated apoptosis through IGFBP5/p53/PUMA signaling axis,on the other hand,induction of C/EBPP also activates Trib3/AKT/mTOR signaling axis through endoplasmic reticulum stress signaling pathway,which leading to autophagy;(4)Autophagy is upstream of apoptosis in METH-induced cell death in vitro,which also contributes to apoptosis.ConclusionNuprl and C/EBP? plays an essential role in METH-caused neuronal apoptosis and autophagy and may be a potential therapeutic target in METH-induced neurotoxicity.