Abstract:

Objective To investigate the changes in serum levels of PTEN-induced putative kinase 1（PINK1）/Parkin related proteins induced by mitochondrial autophagy signaling pathway in patients with vascular Parkinsonism（VP） and its effect on neural function. Methods Totally，55 VP patients（VP group） and 55 healthy subjects（healthy control group） were enrolled from the First Affiliated Hospital of Hebei North University from March 2020 to May 2022. PINK1 and Parkin protein levels were determined. A total of 30 SD rats were selected and classified into control group（15 rats） and VP group（15 rats）. The VP rat model was constructed by intraperitoneal injection of 1-methyl-4-phenyl-1，2，3，6-tetrahydropyridine（MPTP），and the control group was injected with the same amount of 0.9% NaCl solution. For 24 h after the successful construction of the VP model，the survival rate，early apoptosis rate and late apoptosis rate of rat brain tissue were detected by flow cytometry. The mRNA and protein expressions of autophagy genes（PINK1 and Parkin） in rat brain tissue were detected by fluorescence quantitative polymerase chain reaction（PCR） and western blot. Simultaneously，the level of phosphorylation modification of PINK1/Parkin signaling pathway was detected [phosphorylation of PTEN-induced putative kinase 1（p-PINK1） protein and phosphorylation of Parkin（p-Parkin） protein]. The changes of brain ultrastructure were verified in situ by transmission electron microscopy，and the relative expression levels of autophagy proteins [autophagy-related gene（ATG）4 and ATG7] and apoptotic molecules（Bcl-2 and Bax） were detected by western blot. Results The serum PINK1 and Parkin levels in VP group were higher than those in healthy control group（P<0.01）. Compared with the control group，the survival rate of VP rats was decreased（P<0.01），and the early and late apoptosis rates were increased（P<0.01）. The relative expressions of PINK1 mRNA and Parkin mRNA were increased（P<0.01），and the relative expressions of PINK1 protein，Parkin protein，p-PINK1 protein and p-Parkin protein were increased（P<0.01）. The results of transmission electron microscopy showed that autophagy and mitochondrial autophagy were obviously damaged in VP rats. Compared with the control group，the relative expression of Bcl-2 protein in VP rats was decreased（P<0.001），and the relative expressions of Bax，ATG4 and ATG7 proteins were increased（P<0.01）. Conclusions VP can increase brain autophagy and aggravate mitochondrial autophagy damage，which is related to the overactivation of brain autophagy signaling pathway PINK1/Parkin.

Key words: PTEN-induced putative kinase 1/Parkin signaling pathway, Mitochondria, Autophagy damage, Vascular Parkinsonism