ABSTRACT
Objective: To investigate whether lipopolysaccharide induced parkin expression and mitophagy in macrophages.Methods:The murine peritoneal primary macrophages were aseptically isolated from Kunming mice and cultured in complete medium.The mitochondrial membrane potential of macrophages was detected by flow cytometry,after the cells were stimulated with 200 ng/ml LPS and labeled mitochondria with JC-1.The parkin mRNA level of macrophages was detected by RT-PCR, protein levels of parkin and autophagic related protein LC3 Ⅱ and LC3 Ⅰ were determined by Western blot.The distribution and co-localization of parkin with LC3 and mitochondria in macrophages were respectively observed by laser scanning confocal microscope, before and after the cells were treated with LPS.Results: Flow cytometry results after JC-1 staining showed that mitochondrial membrane potential in macrophages was declined after stimulation with 200 ng/ml LPS, and continuously decreased with prolonged treatment time.The mRNA levels of parkin were increased slightly within 6 h after LPS stimulation,but parkin proteins were increased significantly within 6 h after LPS stimulation.The results of parkin distribution showed that parkin was evenly distributed in the cytoplasm at normal status, but became the obvious punctate distribution after LPS stimulation in macrophages.Western blot results showed LC3 Ⅱ/LC3 Ⅰ levels were increased after LPS stimulation, indicating the appearance of macrophage autophagy.Confocal microscopy showed that there were co-localization of parkin,LC3 and mitochondrial in macrophages after LPS stimulation.Conclusion:Parkin expression is increased significantly and mediated mitochondrial autophagy in macrophages after LPS stimulation, which is involved in the clearance of damaged mitochondria,thereby playing a role in regulating macrophage inflammatory response.
ABSTRACT
Objective To investigate the effect of apolipoprotein E gene knock-out(ApoE KO) and high-fat diet on morphology and the expression of mortalin in hippocampal CA_3 neurons of mice, and to explore the impact of these factors on memory and Alzheimer's disease.Methods Ten wild-type and 10 ApoE KO mice were fed with common chow as the control group and the KO group respectively while 10 ApoE KO mice were fed with high fat diet.Twelve weeks later, the weight and the lid of these mice were measured.The brain tissues were observed using HE staining, nissl staining, protargol staining,immunohistochemistry staining and image analysis by computer.Results In the ApoE KO group, weight,total cholesterol, triglyceride, low-density lipoprotein cholesterol were higher than those in the control group,and these changes were more significant in ApoE KO high-fat diet group.The nissl was higher in the ApoE KO group (0.301±0.031) and in ApoE KO high-fat diet group (0.261±0.020) than those in the control group (0.341±0.035, F=18.068, P<0.05).The mortalin in the ApoE KO group (0.322±0.060) and in ApoE KO high-fat diet group (0.391±0.041) were higher than the control group (0.256±0.061, F=15.230, P < 0.05).Conclusions ApoE KO and high-fat diet can reduce nissl, and improve the expression of mortalin.This protein may be involved in the pathogenesis of Alzheimer's disease.