The Regulatory Functionality Of Exosomes In Three Dimensional Culture For Alzheimer's Disease Therapy

Alzheimer's disease(AD)is one of the most common types of central nervous system degenerative disorder in older people.The pathological feature is neuronal function loss or death associated with pathological amyloid-beta(A?)peptide deposition and senile plaques formation in the brain.Reducing A? peptide accumulation could be one of the potential therapeutic approaches for AD.There are currently two types of chemical drugs available,which both just aim to treat some of the symptoms.The cholinesterase inhibitors prevent acetylcholinesterase breaking down acetylcholine and maintaining acetylcholine levels in the brain.The other type of drug is N-methyl-D-aspartic acid receptor,which tries to block the toxicity effects of glutamate.Therefore,it is particularly important to develop more effective treatments to prevent the disease progression and restore memory recognition.In recent years,researchers have found that mesenchymal stem cells(MSCs)could reduce A? deposition,inhibit the Immune inflammation and oxidative stress,and alleviate memory deficits in the AD mouse model,bringing hopes to treat neurodegenerative diseases.However,studies presented that MSCs have exhibited poor differentiation in vivo,implying that the functional recovery of AD pathology might be mediated by the paracrine mechanisms.Exosomes,a class of nanovesicles with lipid membranes,play a vital role in cell-to-cell communications and could improve some pathological conditions by transferring functional biomolecules to recipient cells.Exosomes contain distinct subsets of nucleic acids and proteins,depending upon the cell type from which they are secreted.Significantly,the molecular compositions of exosomes were highly influenced under different physiological or pathological conditions,suggesting changes of the microenvironment in which their original cells reside could induce a modification of the exosomal content and vest the particularly function for disease treatment.Yet,there were few reports to address whether or not the exosomes derived from the culturing cells in three-dimensional dimensionality of the supporting scaffold could exert better therapeutic effects on reducing the A? deposition or ameliorating the memory for AD therapy with specific functional biomolecules.Herein,3D graphene foam scaffold and 2D graphene film were synthesized by the chemical vapor deposition and used as the cultural matrix for human umbilical cord MSCs(hUMSCs),from which the supernatants were obtained to isolate exosomes through a standard method of ultracentrifugation.The typical morphology,particle size,and protein marker of exosomes derived from various dimensionality cultures were detected by transmission electron microscopy,nanoparticle tracking analysis and Western blot.Exosomal miRNA characterized used the Agilent Human miRNA Microarray,and the protein expression tested by Western blot.The AD pathological cells and APP/PS1 double transgenic mice were used to investigate the effects of exosomes on the AD-related neuropathology or cognitive dysfunction.Our results demonstrated that the levels of 195 kinds of miRNAs and proteins,including neprilysin(NEP),insulin-degrading enzyme(IED)and heat shock protein 70(HSP70)were dramatically different in 3-dimensional cultured exosomes(3D-Exo),compared to those from hUMSCs cultured on 2-dimension.3D-Exo group could up-regulate the expression of ?-secretase and down-regulate the ?-secretase to reduce A? production in both AD pathology cells and APP/PS1 transgenic mice.With rescuing A? pathology,3D-Exo exhibited better therapeutic effects on ameliorating the memory and cognitive deficits in AD mice,through their special cargos.In this study,we revealed that three-dimensional culture microenvironment vested unique content of hUMSCs-derived exosomes.3D-Exo exerted better effects in AD treatment by carrying these specifically expressed miRNAs and proteins.These findings provide a new idea for the utility of scaffold materials in the preparation of functional exosomes derived from stem cells for clinical application.