Background Intraneuronal accumulation of hyperphosphorylated tau is a defining hallmark of Alzheimer’s disease(AD).However,mouse models imitating AD-exclusive neuronal tau pathologies are lacking.Methods We generated...Background Intraneuronal accumulation of hyperphosphorylated tau is a defining hallmark of Alzheimer’s disease(AD).However,mouse models imitating AD-exclusive neuronal tau pathologies are lacking.Methods We generated a new tet-on transgenic mouse model expressing truncated human tau N1-368(termed hTau368),a tau fragment increased in the brains of AD patients and aged mouse brains.Doxycycline(dox)was administered in drinking water to induce hTau368 expression.Immunostaining and Western blotting were performed to measure the tau level.RNA sequencing was performed to evaluate gene expression,and several behavioral tests were conducted to evaluate mouse cognitive functions,emotion and locomotion.Results Dox treatment for 1-2 months at a young age induced overt and reversible human tau accumulation in the brains of hTau368 transgenic mice,predominantly in the hippocampus.Meanwhile,the transgenic mice exhibited AD-like high level of tau phosphorylation,glial activation,loss of mature neurons,impaired hippocampal neurogenesis,synaptic degeneration and cognitive deficits.Conclusions This study developed a well-characterized and easy-to-use tool for the investigations and drug development for AD and other tauopathies.展开更多
Background Synaptic degeneration occurs in the early stage of Alzheimer’s disease(AD)before devastating symptoms,strongly correlated with cognitive decline.Circular RNAs(circRNAs)are abundantly enriched in neural tis...Background Synaptic degeneration occurs in the early stage of Alzheimer’s disease(AD)before devastating symptoms,strongly correlated with cognitive decline.Circular RNAs(circRNAs)are abundantly enriched in neural tissues,and aberrant expression of circRNAs precedes AD symptoms,significantly correlated with clinical dementia severity.However,the direct relationship between circRNA dysregulation and synaptic impairment in the early stage of AD remains poorly understood.Methods Hippocampal whole-transcriptome sequencing was performed to identify dysregulated circRNAs and miRNAs in 4-month-old wild-type and APP/PS1 mice.RNA antisense purification and mass spectrometry were utilized to unveil interactions between circRIMS2 and methyltransferase 3,N6-adenosine-methyltransferase complex catalytic subunit(METTL3).The roles of circRIMS2/miR-3968 in synaptic targeting of UBE2K-mediated ubiquitination of GluN2B subunit of NMDA receptor were evaluated via numerous lentiviruses followed by morphological staining,co-immunoprecipitation and behavioral testing.Further,a membrane-permeable peptide was used to block the ubiquitination of K1082 on GluN2B in AD mice.Results circRIMS2 was significantly upregulated in 4-month-old APP/PS1 mice,which was mediated by METTL3-dependent N6-methyladenosine(m6A)modification.Overexpression of circRIMS2 led to synaptic and memory impairments in 4-month-old C57BL/6 mice.MiR-3968/UBE2K was validated as the downstream of circRIMS2.Elevated UBE2K induced synaptic dysfunction of AD through ubiquitinating K1082 on GluN2B.Silencing METTL3 or blocking the ubiquitination of K1082 on GluN2B with a short membrane-permeable peptide remarkably rescued synaptic dysfunction in AD mice.Conclusions In conclusion,our study demonstrated that m6A-modified circRIMS2 mediates the synaptic and memory impairments in AD by activating the UBE2K-dependent ubiquitination and degradation of GluN2B via sponging miR-3968,providing novel therapeutic strategies for AD.展开更多
基金This study was supported in part by the Natural Science Foundation of China(82230041,91949205,31730035 and 81721005),the Fundamental Research Funds for the Central Universities(YCJJ202203019)National Key R&D Program of China(2016YFC1305800)Guangdong Provincial Key S&T Program(018B030336001).
文摘Background Intraneuronal accumulation of hyperphosphorylated tau is a defining hallmark of Alzheimer’s disease(AD).However,mouse models imitating AD-exclusive neuronal tau pathologies are lacking.Methods We generated a new tet-on transgenic mouse model expressing truncated human tau N1-368(termed hTau368),a tau fragment increased in the brains of AD patients and aged mouse brains.Doxycycline(dox)was administered in drinking water to induce hTau368 expression.Immunostaining and Western blotting were performed to measure the tau level.RNA sequencing was performed to evaluate gene expression,and several behavioral tests were conducted to evaluate mouse cognitive functions,emotion and locomotion.Results Dox treatment for 1-2 months at a young age induced overt and reversible human tau accumulation in the brains of hTau368 transgenic mice,predominantly in the hippocampus.Meanwhile,the transgenic mice exhibited AD-like high level of tau phosphorylation,glial activation,loss of mature neurons,impaired hippocampal neurogenesis,synaptic degeneration and cognitive deficits.Conclusions This study developed a well-characterized and easy-to-use tool for the investigations and drug development for AD and other tauopathies.
基金supported by the National Natural Science Foundation of China(82372337,81500925 to Xiong Wang,81801062 to Xiaoguang Li)Tongji Hospital(HUST)Foundation for Excellent Young Scientist(2020YQ01-11 to Xiong Wang)the Natural Science Foundation of Hubei Province(2022CFB150 to Huijun Li).
文摘Background Synaptic degeneration occurs in the early stage of Alzheimer’s disease(AD)before devastating symptoms,strongly correlated with cognitive decline.Circular RNAs(circRNAs)are abundantly enriched in neural tissues,and aberrant expression of circRNAs precedes AD symptoms,significantly correlated with clinical dementia severity.However,the direct relationship between circRNA dysregulation and synaptic impairment in the early stage of AD remains poorly understood.Methods Hippocampal whole-transcriptome sequencing was performed to identify dysregulated circRNAs and miRNAs in 4-month-old wild-type and APP/PS1 mice.RNA antisense purification and mass spectrometry were utilized to unveil interactions between circRIMS2 and methyltransferase 3,N6-adenosine-methyltransferase complex catalytic subunit(METTL3).The roles of circRIMS2/miR-3968 in synaptic targeting of UBE2K-mediated ubiquitination of GluN2B subunit of NMDA receptor were evaluated via numerous lentiviruses followed by morphological staining,co-immunoprecipitation and behavioral testing.Further,a membrane-permeable peptide was used to block the ubiquitination of K1082 on GluN2B in AD mice.Results circRIMS2 was significantly upregulated in 4-month-old APP/PS1 mice,which was mediated by METTL3-dependent N6-methyladenosine(m6A)modification.Overexpression of circRIMS2 led to synaptic and memory impairments in 4-month-old C57BL/6 mice.MiR-3968/UBE2K was validated as the downstream of circRIMS2.Elevated UBE2K induced synaptic dysfunction of AD through ubiquitinating K1082 on GluN2B.Silencing METTL3 or blocking the ubiquitination of K1082 on GluN2B with a short membrane-permeable peptide remarkably rescued synaptic dysfunction in AD mice.Conclusions In conclusion,our study demonstrated that m6A-modified circRIMS2 mediates the synaptic and memory impairments in AD by activating the UBE2K-dependent ubiquitination and degradation of GluN2B via sponging miR-3968,providing novel therapeutic strategies for AD.
