Background:Intracellular accumulation of the microtubule-associated protein tau and its hyperphosphorylated forms is a key neuropathological feature of Alzheimer’s disease(AD).Melatonin has been shown to prevent tau ...Background:Intracellular accumulation of the microtubule-associated protein tau and its hyperphosphorylated forms is a key neuropathological feature of Alzheimer’s disease(AD).Melatonin has been shown to prevent tau hyperphosphorylation in cellular and animal models.However,the molecular mechanisms by which melatonin attenuates tau hyperphosphorylation and tau-related pathologies are not fully understood.Methods:Immunofluorescence,immunoblotting analysis and thioflavin-S staining were employed to examine the effects of early and late treatment of melatonin on tau-related pathology in hTau mice,in which nonmutated human tau is overexpressed on a mouse tau knockout background.High-throughput microRNA(miRNA)sequencing,quantitative RT-PCR,luciferase reporter assay and immunoblotting analysis were performed to determine the molecular mechanism.Results:We found that both early and late treatment of melatonin efficiently decreased the phosphorylation of soluble and insoluble tau at sites related to AD.Moreover,melatonin significantly reduced the number of neurofibrillary tangles(NFTs)and attenuated neuronal loss in the cortex and hippocampus.Furthermore,using miRNA microarray analysis,we found that miR-504-3p expression was upregulated by melatonin in the hTau mice.The administration of miR-504-3p mimics dramatically decreased tau phosphorylation by targeting p39,an activator of the well-known tau kinase cyclin-dependent kinase 5(CDK5).Compared with miR-504-3p mimics alone,co-treatment with miR-504-3p mimics and p39 failed to reduce tau hyperphosphorylation.Conclusions:Our results suggest for the first time that melatonin alleviates tau-related pathologies through upregulation of miR-504-3p expression by targeting the p39/CDK5 axis and provide novel insights into AD treatment strategies.展开更多
基金the National Natural Science Foundation of China(81901071 and 81970993)the Natural Science Foundation of Fujian Province(2019J01297 and 2019J05072)the Medical Innovation Grant of Fujian Province(2019-CX-36).
文摘Background:Intracellular accumulation of the microtubule-associated protein tau and its hyperphosphorylated forms is a key neuropathological feature of Alzheimer’s disease(AD).Melatonin has been shown to prevent tau hyperphosphorylation in cellular and animal models.However,the molecular mechanisms by which melatonin attenuates tau hyperphosphorylation and tau-related pathologies are not fully understood.Methods:Immunofluorescence,immunoblotting analysis and thioflavin-S staining were employed to examine the effects of early and late treatment of melatonin on tau-related pathology in hTau mice,in which nonmutated human tau is overexpressed on a mouse tau knockout background.High-throughput microRNA(miRNA)sequencing,quantitative RT-PCR,luciferase reporter assay and immunoblotting analysis were performed to determine the molecular mechanism.Results:We found that both early and late treatment of melatonin efficiently decreased the phosphorylation of soluble and insoluble tau at sites related to AD.Moreover,melatonin significantly reduced the number of neurofibrillary tangles(NFTs)and attenuated neuronal loss in the cortex and hippocampus.Furthermore,using miRNA microarray analysis,we found that miR-504-3p expression was upregulated by melatonin in the hTau mice.The administration of miR-504-3p mimics dramatically decreased tau phosphorylation by targeting p39,an activator of the well-known tau kinase cyclin-dependent kinase 5(CDK5).Compared with miR-504-3p mimics alone,co-treatment with miR-504-3p mimics and p39 failed to reduce tau hyperphosphorylation.Conclusions:Our results suggest for the first time that melatonin alleviates tau-related pathologies through upregulation of miR-504-3p expression by targeting the p39/CDK5 axis and provide novel insights into AD treatment strategies.
