The Effect Of MiR-142-3p On Pathogenesis Of Prion Diseases

Prion disease is a fatal and infectious degenerative disease which mainly affectsthe central nervous system, the main infectious substances is misfolded prion protein(PrPsc).one a time, the outbreak of mad cow disease caused a huge disaster to theanimal husbandry, while beef infected with BSE flow into consumer market, itseriously affected people’s health.The pathegenisis of prion disease is still unclear,many studies showed that abnormal miRNA regulatory network was a potential riskfactor of prion disease. MicroRNA (miRNA or miR) are conserved, single-stranded,18-24nucleotide non-protein-coding RNA, they regulate protein expression atpost-transcriptional level. Although some abnormal expressed miRNA was repored inprion disease, the biological functions of miRNA are not yet fully understood.The aims of this reseach were to investigate the expression of miRNA change inscrapie factor22L infected neuro-2a (ScN2a) and in prion disease infected tissues(including brain, the hippocampus, the medulla oblongata, spleen);and then useScN2a cell model to investigate the role of miR-142-3p on pathogenesis of priondisease.it had an important role in investigating the pathogenesis of prion disease, andin finding effective diagnosis and detection methods as soon as possible for priondisease.for example,mad cow disease.After our work, we can make these conclusions:1.The results of real time-PCRshowed that miR-142-3p was upregulated in prion infected brain, medulla oblongata,hippocampus, spleen and ScN2a cell. Among them, miR-142-3p in spleen wasupregulated more than10times.2.The morphological analysis showed that, whenmiR-142-3p was over-expressed, compared with negative control, cells agglomeratedand appeared some phenomena that similar to neurodegeneration such as thecytoplasm became narrow with vacuoles generated, cell body became small,whilemiR-142-3p was low-expressed,cell seemed to grow well; MTT assay showed that24hours after transfection, over-expressed miR-142-3p could significantly repress cellproliferation,while low-expressed miR-142-3p could increase cell plolificatin,especially after72hours.3.Transmission electron microscopy revealed there weresome lipid sediments in the cytoplasm of over-expressed miR-142-3p ScN2a cells, vacuole appeared in mitochondria and cytoplasm.4. Western blot demonstratedover-expressed miR-142-3p could significantly increase the expression of PrPsc, whilelow-expressed miR-142-3p can inhibit the expression of PrPsc.5.Using bioinformaticstools, several possible target genes of miR-142-3p were forecasted, we found most oftarget genes involved in cellular macromolecules positioning, protein transport,vesicle-mediated transport, transcriptional regulation, neuronal development and celldifferentiation, neuronal differentiation and synaptic morphology and other biologicalprocesses;miR-142-3p accelerated the development of prion disease by regulating thepossible target genes, for example ATF7IP and MYH9.