Erythrocyte Membrane-encapsulated Celecoxib Improves the Cognitive Decline of Alzheimer’s Disease by Concurrently Inducing Neurogenesis and Reducing Apoptosis in APP/PS1 Transgenic Mice

Author:Guo Jing Wen

Supervisor:wang zhan you wang zuo


Degree Year:2017





Alzheimer’s disease(AD)is characterized by the loss of neurogenesis and excessive induction of apoptosis.The induction of neurogenesis and inhibition of apoptosis may be a promising therapeutic approach to combating the disease.Celecoxib(CB),a cyclooxygenase-2(COX-2)specific inhibitor,could offer neuroprotection.Specifically,the CB-encapsulated erythrocyte membranes(CB-RBCMs)sustained the release of CB over a period of 72 h in vitro and exhibited high brain biodistribution efficiency following intranasal administration,which resulted in the clearance of aggregated(3-amyloid proteins(Aβ)in neurons.The high accumulation of the CB-RBCMs in neurons resulted in a decrease in the neurotoxicity of CB and an increase in the migratory activity of neurons,and alleviated cognitive decline in APP/PS1 transgenic(Tg)mice.Indeed,COX-2 metabolic products including prostaglandin E2(PGE2)and PGD2,PGE2 induced neurogenesis by enhancing the expression of SOD2 and 14-3-3ζ,and PGD2 stimulated apoptosis by increasing the expression of BIK and decreasing the expression of ARRB1.To this end,the CB-RBCMs achieved better therapeutic effects on AD than the phospholipid membrane-encapsulated CB liposomes(CB-PSPD-LPs)in terms of concurrently increasing neurogenesis and decreasing apoptosis.Therefore,CB-RBCMs provide a rational design to treat AD by promoting the self-repairing capacity of the brain.Specifically,the CB-RBCMs and CB-PSPD-LPs were prepared by extrusion and thin film-dispersion methods,respectively.In addition,the CB-QD compound was synthesized to study the distribution of CB in neurons or the brian of C57BL/6 mice.The product of CB-QD was determined by IR spectroscopy.The particle size was measured by Malvern Nano and the average particle diameter of PSPD-LPs and RBCMs groups were 125.6±4.7 and 93.2±3.8 nm,respectively.By TEM,the preparations showed spherical and uniform in size.The cytotoxicity of deliveries was evaluated by the MTT method and the results demonstrated that CB showed relative lower toxicity after encapsulated in RBCMs or PSPD-LPs.Meanwhile,the carriers do not show any cytotoxicity.Moreover,the release profile in vitro showed the RBCMs could sustain the release of CB to 72 h.The distribution of CB in the neurons of the brain was analyzed by confocal microscopy.The results revealed that the CB-RBCMs achieved the higher distribution of CB in the brain.On the other hand,there was no significant retention in the liver,kidney and cardiovascular system.Therefore,the deliveries could alleviate the risks of side effect.Western Blot and Real-Time PCR assays were employed to evaluate the mRNA and protein levels of SOD,14-3-3ζ,BIK and ARRB1 after treating with CB-RBCMs or CB-PSPD-LPs.The results demonstrated that CB-RBCMs could up-regulate the expression of SOD,14-3-3ζ and ARRB1,whereas down-regulate the exopression of BIK,which potentially contribute their roles in neurogenesis and apoptosis.To this end,the micro-channel and transwell assays were used to investigate the migration of neurons and the results revealed that the CB-RBCMs group improved the migration of both of N2a and SH-SY5Y.For apoptosis,CB preparations also improved the Aβ-induced apoptosis by flow cytometry experiment.Apart from these experiments,BrdU assay was used to determine the neurogenesis.The results demonstrated that the RBCMs group had more labeled neurons than other groups,which indicated the efficacy of RBCMs on improving the therapeutic effects of CB.Finally,the experiments of the Morris maze test and nesting constructions were carried out to determine the learning abililty of APP/PS1 mice.The results demonstrated that CB-RBCMs achieved better therapeutic effects on improving the loss of learning ability in APP/PS1 Tg mice.Collectively,the current study constructed CB-PSPD-LPs and CB-RBCMs preparations,which achieved high brain distribution,low-cytotoxicity,induction of neurogenesis,inhibition of apoptosis,which improved the cognitive decline of AD.