The Pathogenic Mechanism Of ATP13A2 (F182L) Gene Targeting Mice

Kufor-Rakeb syndrome(KRS)is an early-onset Parkinson's disease that not only has clinical symptoms of Parkinson's disease but also symptoms such as paralysis and cognitive decline.A mutation or deletion of ATP13A2 causes KRS.In vitro experiments revealed that the F182 L mutation was more damaging to cells.So in which way does F182 L cause disease in animals? This research will study the pathogenesis of ATP13A2(F182L)transgenic mice.First,design a gene sequence carrying EYFP-IRES-ATP13A2(F182L)-HIS-V5 and insert it into normal mice.After breeding,hybridization and mass reproduction,genotype identification was carried out.Whole brain neurons of transgenic mice express ATP13A2(F182L)gene.Behavioral tests such as forced swimming for genetic mice during 15 months revealed that there were certain behavioral disorders in transgenic mice,and the frequency of electrical signals in neurons in the substantia nigra was significantly reduced.Further biochemistry detection of whole brain dopaminergic neurons found that the number of dopaminergic neurons was significantly lower than that of the control group,while the anti-apoptosis protein Bcl2 was decreased,and BAX,AIF and other pro-apoptosis-related proteins were detected with an increase.Therefore,abnormal behavior in transgenic mice is associated with excessive death and decreased activity of neurons.To delve into explore the causes of neuronal death in transgenic mice,The detection of ?-synuclein(?-syn)did not reveal ?-syn aggregation,which is different from the pathogenesis of Parkinson's model.Further detection of autophagic lysosomes and mTOR signaling pathway revealed that the mTOR pathway was activated,autophagy-related proteins such as LC3 II and Beclin1 were decreased,autophagy activity was inhibited,and lysosomal function was impaired.Normal ATP13A2 is localized to lysosomes.But ATP13A2(F182L)was found to co-localize with the endoplasmic reticulum and a part of ATP13A2(F182L)was also observed for co-localization of the mitochondria.Because the ATP13A2(F182L)mutation is localized to the endoplasmic reticulum and mitochondria,experiment detected that the fusion protein Mfn2,the membrane protein Tom20 and the mitochondrial continuity was decreased,along with morphology changes,which affected its function.The endoplasmic reticulum related protein was detected in the endoplasmic reticulum of the transgenic mice giving indication that the endoplasmic reticulum PERK pathway was activated and inducing ER stress,and the pro-apoptotic protein CHOP and Cleaved Caspase-3.This indicates that the PERK-CHOP pathway is activated and the cell has initiated the apoptosis program.This is the main cause of neuronal death.In order to explore how to alleviate the behavioral abnormalities of transgenic mice,the research of optogenetic experiments found that light stimulation of the substantia nigra of the transgenic mouse induces an increase in neuronal electrical signals,which indicates that the neuronal activity is up-regulated,so it might be a treatment option that can improves behavior as well.Taking together,ATP13A2(F182L)mutations localize to the endoplasmic reticulum,causing excessive endoplasmic reticulum stress,disturbing mitochondrial and lysosomal functions,triggering autophagic pathway barriers,resulting in decreased neuronal activity and massive cell death and ensuing behavior abnormalities in ATP13A2(F182L)transgenic mice.Optogenetic can improve neuronal activity.This may bring a new direction for the treatment of KRS.