Regular exercise has been shown to reduce the risk of Alzheimer’s disease(AD).Our previous study showed that the protein aquaporin 4(AQP4),which is specifically expressed on the paravascular processes of astrocytes,i...Regular exercise has been shown to reduce the risk of Alzheimer’s disease(AD).Our previous study showed that the protein aquaporin 4(AQP4),which is specifically expressed on the paravascular processes of astrocytes,is necessary for glymphatic clearance of extracellular amyloid beta(Aβ)from the brain,which can delay the progression of Alzheimer’s disease.However,it is not known whether AQP4-regulated glymphatic clearance of extracellular Aβis involved in beneficial effects of exercise in AD patients.Our results showed that after 2 months of voluntary wheel exercise,APP/PS1 mice that were 3 months old at the start of the intervention exhibited a decrease in Aβburden,glial activation,perivascular AQP4 mislocalization,impaired glymphatic transport,synapse protein loss,and learning and memory defects compared with mice not subjected to the exercise intervention.In contrast,APP/PS1 mice that were 7 months old at the start of the intervention exhibited impaired AQP4 polarity and reduced glymphatic clearance of extracellular Aβ,and the above-mentioned impairments were not alleviated after the 2-month exercise intervention.Compared with age-matched APP/PS1 mice,AQP4 knockout APP/PS1 mice had more serious defects in glymphatic function,Aβplaque deposition,and cognitive impairment,which could not be alleviated after the exercise intervention.These findings suggest that AQP4-dependent glymphatic transport is the neurobiological basis for the beneficial effects of voluntary exercises that protect against the onset of AD.展开更多
Interleukin-4 plays an important protective role in Alzheimer’s disease by regulating microglial phenotype,phagocytosis of amyloid-β,and secretion of anti-inflammatory and neurotrophic cytokines.Recently,increasing ...Interleukin-4 plays an important protective role in Alzheimer’s disease by regulating microglial phenotype,phagocytosis of amyloid-β,and secretion of anti-inflammatory and neurotrophic cytokines.Recently,increasing evidence has suggested that autophagy regulates innate immunity by affecting M1/M2 polarization of microglia/macrophages.However,the role of interleukin-4 in microglial autophagy is unknown.In view of this,BV2 microglia were treated with 0,10,20 or 50 ng/mL interleukin-4 for 24,48,or 72 hours.Subsequently,light chain 3-II and p62 protein expression levels were detected by western blot assay.BV2 microglia were incubated with interleukin-4(20 ng/mL,experimental group),3-methyladenine(500μM,autophagy inhibitor,negative control group),rapamycin(100 nM,autophagy inductor,positive control group),3-methyladenine+interleukin-4(rescue group),or without treatment for 24 hours,and then exposed to amyloid-β(1μM,model group)or vehicle control(control)for 24 hours.LC3-II and p62 protein expression levels were again detected by western blot assay.In addition,expression levels of multiple markers of M1 and M2 phenotype were assessed by real-time fluorescence quantitative polymerase chain reaction,while intracellular and supernatant amyloid-βprotein levels were measured by enzyme-linked immunosorbent assay.Our results showed that interleukin-4 induced microglial autophagic flux,most significantly at 20 ng/mL for 48 hours.Interleukin-4 pretreated microglia inhibited blockade of amyloid-β-induced autophagic flux,and promoted amyloid-βuptake and degradation partly through autophagic flux,but inhibited switching of amyloid-β-induced M1 phenotype independent on autophagic flux.These results indicate that interleukin-4 pretreated microglia increases uptake and degradation of amyloid-βin a process partly mediated by autophagy,which may play a protective role against Alzheimer’s disease.展开更多
基金supported by the National Natural Science Foundation of China,No.81772454(to TW)Natural Science Foundation of Jiangsu,China,No.BK20190655(to QL).
文摘Regular exercise has been shown to reduce the risk of Alzheimer’s disease(AD).Our previous study showed that the protein aquaporin 4(AQP4),which is specifically expressed on the paravascular processes of astrocytes,is necessary for glymphatic clearance of extracellular amyloid beta(Aβ)from the brain,which can delay the progression of Alzheimer’s disease.However,it is not known whether AQP4-regulated glymphatic clearance of extracellular Aβis involved in beneficial effects of exercise in AD patients.Our results showed that after 2 months of voluntary wheel exercise,APP/PS1 mice that were 3 months old at the start of the intervention exhibited a decrease in Aβburden,glial activation,perivascular AQP4 mislocalization,impaired glymphatic transport,synapse protein loss,and learning and memory defects compared with mice not subjected to the exercise intervention.In contrast,APP/PS1 mice that were 7 months old at the start of the intervention exhibited impaired AQP4 polarity and reduced glymphatic clearance of extracellular Aβ,and the above-mentioned impairments were not alleviated after the 2-month exercise intervention.Compared with age-matched APP/PS1 mice,AQP4 knockout APP/PS1 mice had more serious defects in glymphatic function,Aβplaque deposition,and cognitive impairment,which could not be alleviated after the exercise intervention.These findings suggest that AQP4-dependent glymphatic transport is the neurobiological basis for the beneficial effects of voluntary exercises that protect against the onset of AD.
基金supported by the Natural Science Foundation of Liaoning Province of China,No.20170541036(to HYL)
文摘Interleukin-4 plays an important protective role in Alzheimer’s disease by regulating microglial phenotype,phagocytosis of amyloid-β,and secretion of anti-inflammatory and neurotrophic cytokines.Recently,increasing evidence has suggested that autophagy regulates innate immunity by affecting M1/M2 polarization of microglia/macrophages.However,the role of interleukin-4 in microglial autophagy is unknown.In view of this,BV2 microglia were treated with 0,10,20 or 50 ng/mL interleukin-4 for 24,48,or 72 hours.Subsequently,light chain 3-II and p62 protein expression levels were detected by western blot assay.BV2 microglia were incubated with interleukin-4(20 ng/mL,experimental group),3-methyladenine(500μM,autophagy inhibitor,negative control group),rapamycin(100 nM,autophagy inductor,positive control group),3-methyladenine+interleukin-4(rescue group),or without treatment for 24 hours,and then exposed to amyloid-β(1μM,model group)or vehicle control(control)for 24 hours.LC3-II and p62 protein expression levels were again detected by western blot assay.In addition,expression levels of multiple markers of M1 and M2 phenotype were assessed by real-time fluorescence quantitative polymerase chain reaction,while intracellular and supernatant amyloid-βprotein levels were measured by enzyme-linked immunosorbent assay.Our results showed that interleukin-4 induced microglial autophagic flux,most significantly at 20 ng/mL for 48 hours.Interleukin-4 pretreated microglia inhibited blockade of amyloid-β-induced autophagic flux,and promoted amyloid-βuptake and degradation partly through autophagic flux,but inhibited switching of amyloid-β-induced M1 phenotype independent on autophagic flux.These results indicate that interleukin-4 pretreated microglia increases uptake and degradation of amyloid-βin a process partly mediated by autophagy,which may play a protective role against Alzheimer’s disease.
