The Role,Molecular Mechanism And Intervention Therapy Of PDCD4 In Parkinson’s Disease

Parkinson’s disease(PD)is the second common neurodegenerative disease.Pathological features include insoluble aggregation of a-synuclein(a-syn)and damage of dopaminergic neurons;The main symptoms include static tremor,bradykinesia,etc.,which brings great pain to the patient’s life;Because the pathogenesis is still unclear,there is no effective treatment at present.Therefore,revealing the pathogenesis of PD is of great value for finding new drug targets and drug research and development.Programmed cell death factor 4(PDCD4)is a protein translation inhibitor that participates in the occurrence and development of many diseases,such as inhibiting tumor,promoting obesity and depression,but its role in PD is still unclear.It is known that the damage of lysosome function is one of the pathogenesis of Parkinson’s disease.It has been found that PDCD4 can negatively regulate the key transcription factor TFEB of lysosome and then negatively regulate the function of lysosome,suggesting that PDCD4 may be related to PD.Objective:(1)To study the role of PDCD4 in PD;(2)To explore the molecular mechanism of PDCD4 in PD;(3)To explore the method of intervention and treatment of PD with PDCD4 as the target.Methods:(1)Use the chemicals that cause PD(MPTP and 6-OHDA)and a-syn’s preformed fibroblasts(PFFs)stimulate cell lines;Interference or overexpression of PDCD4.The relationship between PDCD4 and PD was analyzed by protein immunoblotting(WB).(2)Injection overexpression a-syn’s adeno-associated(AAV)virus was used to establish the PD model,and the model was established by climbing rod,balance beam,rotating rod and other behavioral tests,immunohistochemistry and WB methods.(3)After modeling,compare the effects of PDCD4 gene knockout and KO complement PDCD4 on PD-like behavior,neuron damage and a-syn accumulation in mice,and determine the role of PDCD4 in PD.(4)The effects of PDCD4 on the expression of TFE3 and TFEB were determined in vitro and in vivo experiments.After the striatum region interfered with TFE3 and TFEB in vivo,the effects on the behavior and pathology of PD mice in KO group were analyzed.(5)Study the molecular mechanism of PDCD4 regulating TFE3 by immunofluorescence,WB,IP and other methods.(6)Intraperitoneal injection of modified PDCD4 small interfering RNA(RVG-siPDCD4)to analyze the therapeutic effect on PD.Results:(1)In vitro,chemical drugs and a-syn stimulated nerve cells to significantly up-regulate PDCD4;The expression level of PDCD4 was positively correlated with the accumulation of α-syn.After overexpression of PDCD4,the accumulation ofα-syn increased,while after silencing of PDCD4,the accumulation of α-syn decreased.(2)In vivo,knockout of PDCD4 improves PD-like behavior and reduces the accumulation of α-syn and the damage of dopamine neurons;The protective effect of PDCD4 KO on PD disappeared after the striatum was replenished with PDCD4;Explain that PDCD4 has the effect of promoting PD.(3)Mechanism exploration found that overexpression of PDCD4 inhibited the expression of key lysosomal transcription factors-TFE3 and TFEB,and knockout of PDCD4 up-regulated the expression of TFE3 and TFEB;After silencing the expression of TFE3 and TFEB,the improvement of PDCD4 knockout on PD disappeared;Explain that PDCD4 promotes PD by inhibiting TFE3 and TFEB.(4)It is found that PDCD4 negatively regulates TFE3 translation in an eIF4A-dependent manner through its MA-3 functional domain.(5)With PDCD4 as the target,RVG-siPDCD4 targeting the brain was prepared and administered intraperitoneally,which significantly improved the behavior and neuronal damage of PD.Conclusions/innovativeness and significance:(1)It was found that α-syn induced high expression of PDCD4,and elevated PDCD4 promoted PD;PDCD4 may be involved in the occurrence and development of PD.(2)It was found that PDCD4 aggravates PD by inhibiting the translation of TFE3 and TFEB,and TFE3 is a new target molecule for PDCD4.(3)RVG-siPDCD4 has the effect of treating PD and provides a new strategy for the development of PD drugs.Limitations:The specific molecular mechanism of α-syn up-regulating PDCD4 expression has not been determined due to the relationship of time.