HMGA1 Induction Of MiR-103/107 Forms A Feedback Loop To Regulate Autophagy In Parkinson's Disease Through CDK5R1/CDK5 Signal Pathway

BACKGROUND:Parkinson's Disease(PD)is a kind of complex neurodegenerative diseases.The motor and non-motor symptoms of PD caused by the loss of dopamine neurons mainly in the substantia nigra(SN)and striatum in the brain.As we all know,the pathogenesis is very complex,and the symptomatic treatment alone cannot prevent the progression of PD effectively.Autophagy dysfunction has been found to be directly related to the occurrence and progression of PD.However,its underlying mechanism remains unclear.Based on current evidence,autophagy regulation appears to be an effective intervention strategy for neurodegenerative diseases.Therefore,it is important to uncover the underlying mechanisms of autophagy in PD.PURPOSESAutophagy is a degradation process mainly depending lysosomal protein,it is used to eliminate damaged organelles and protein aggregates.The balance of autophagy is essential for neuronal survival.Autophagy dysfunction in dopamine neurons plays a key role in the progression of PD,however,its underlying mechanism remains unclear.High-mobility group Al(HMGA1)and miR-103/107 family are important regulators of autophagy.Based on our previous research results and literature retrieval,HMGA1 interacts with miR-103/107 family to regulate the autophagy of dopamine neurons.Therefore,this project intends to demonstrate at molecular,cellular,and animal model levels,that HMGA1 expression is increased and miR-103/107 expression is decreased during the pathological process of PD;HMGA1 maintains the expression of miR-103/107 by directly binding to the promoter of miR-103/107;At the same time,miR-103/107 promotes the expression of HMGA1 and form a negative feedback loop with each other;This loop regulates autophagy dysfunction and death of dopaminergic neurons through the CDK5R1/CDK5 signaling pathway.This project would further enrich the existing understanding of the molecular biological mechanism of PD and provide a new target for the subsequent drug therapy of PD target genes based on the HMGA1 signaling pathway.METHODSMolecular level:through down-regulation of HMGA1 and overexpression/down-regulation of miR103/107 family,western blotting techniques and real-time fluorescence-based quantitative PCR were used to analyze their expression in dopaminergic neurons and their inter-regulatory relationships.Chromatin immunoprecipitation(ChIP)assay and dual luciferase reporter assay were used to detect the binding of HMGA1 to miR-103/107 family.Cellular level:through down-regulation of HMGA1 and overexpression/down-regulation of miR-103/107,western blotting and flow cytometry were used to detect the changes of cell phenotypes associated moleculars,so as to clarify the role of HMGA1/miR-103/107 loop in the autophagy and death of NM9D cells.Animal level:MPTP was used to prepare the sub-acute PD model,and the expression of HMGA1 was detected by western blotting and real-time fluorescence quantitative PCR.Stereotactic injection technique was used to down-regulate the expression of HMGA1 in the substantia nigra of mice,and immunofluorescence,western blotting and real-time fluorescence quantitative PCR were used to detect the effect of HMGA1-mediated loop in the autophagy and neurotoxicity of dopaminergic neurons in PD.RESULTS1.In the sub-acute PD models of vivo and vitro,the expression of HMGA1 was significantly increased,while the expression of miR-103/107 was decreased;2.Downregulation of HMGA1 aggravates MPTP/MPP+-induced autophagy impairment and neurotoxic effects;3.HMGA 1 induction of miR-103/107 forms a feedback loop to regulate autophagy impairment and neural cell death through CDK5R1/CDK5 signal pathway in PD.CONCLUSIONHMGA1 induction of miR-103/107 forms a feedback loop to regulate autophagy impairment and neural cell death through CDK5R1/CDK5 signal pathway in PD.