RESUMEN
Dipeptide repeat proteins are a major pathogenic feature of C9orf72 amyotrophic lateral sclerosis (C9ALS)/frontotemporal dementia (FTD) pathology, but their physiological impact has yet to be fully determined. Here we generated C9orf72 dipeptide repeat knock-in mouse models characterized by expression of 400 codon-optimized polyGR or polyPR repeats, and heterozygous C9orf72 reduction. (GR)400 and (PR)400 knock-in mice recapitulate key features of C9ALS/FTD, including cortical neuronal hyperexcitability, age-dependent spinal motor neuron loss and progressive motor dysfunction. Quantitative proteomics revealed an increase in extracellular matrix (ECM) proteins in (GR)400 and (PR)400 spinal cord, with the collagen COL6A1 the most increased protein. TGF-ß1 was one of the top predicted regulators of this ECM signature and polyGR expression in human induced pluripotent stem cell neurons was sufficient to induce TGF-ß1 followed by COL6A1. Knockdown of TGF-ß1 or COL6A1 orthologues in polyGR model Drosophila exacerbated neurodegeneration, while expression of TGF-ß1 or COL6A1 in induced pluripotent stem cell-derived motor neurons of patients with C9ALS/FTD protected against glutamate-induced cell death. Altogether, our findings reveal a neuroprotective and conserved ECM signature in C9ALS/FTD.
Asunto(s)
Esclerosis Amiotrófica Lateral , Demencia Frontotemporal , Células Madre Pluripotentes Inducidas , Animales , Humanos , Ratones , Demencia Frontotemporal/patología , Esclerosis Amiotrófica Lateral/metabolismo , Factor de Crecimiento Transformador beta1 , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Neuronas Motoras/metabolismo , Drosophila , Matriz Extracelular/metabolismo , Dipéptidos/metabolismo , Expansión de las Repeticiones de ADN/genéticaRESUMEN
Evidence suggests interplay among the three major risk factors for Alzheimer's disease (AD): age, APOE genotype, and sex. Here, we present comprehensive datasets and analyses of brain transcriptomes and blood metabolomes from human apoE2-, apoE3-, and apoE4-targeted replacement mice across young, middle, and old ages with both sexes. We found that age had the greatest impact on brain transcriptomes highlighted by an immune module led by Trem2 and Tyrobp, whereas APOE4 was associated with upregulation of multiple Serpina3 genes. Importantly, these networks and gene expression changes were mostly conserved in human brains. Finally, we observed a significant interaction between age, APOE genotype, and sex on unfolded protein response pathway. In the periphery, APOE2 drove distinct blood metabolome profile highlighted by the upregulation of lipid metabolites. Our work identifies unique and interactive molecular pathways underlying AD risk factors providing valuable resources for discovery and validation research in model systems and humans.
Asunto(s)
Envejecimiento/genética , Enfermedad de Alzheimer/genética , Apolipoproteínas E/genética , Encéfalo/metabolismo , Serpinas/genética , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/inmunología , Factores de Edad , Enfermedad de Alzheimer/metabolismo , Animales , Apolipoproteína E2/genética , Apolipoproteína E3/genética , Apolipoproteína E4/genética , Femenino , Expresión Génica , Perfilación de la Expresión Génica , Redes Reguladoras de Genes , Genotipo , Humanos , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Metaboloma , Ratones , Ratones Transgénicos , Factores Protectores , Receptores Inmunológicos/genética , Receptores Inmunológicos/inmunología , Factores de Riesgo , Factores Sexuales , Respuesta de Proteína Desplegada/genéticaRESUMEN
The apolipoprotein E (APOE) ε4 allele is the strongest genetic risk factor for late-onset Alzheimer's disease mainly by driving amyloid-ß pathology. Recently, APOE4 has also been found to be a genetic risk factor for Lewy body dementia (LBD), which includes dementia with Lewy bodies and Parkinson's disease dementia. How APOE4 drives risk of LBD and whether it has a direct effect on α-synuclein pathology are not clear. Here, we generated a mouse model of synucleinopathy using an adeno-associated virus gene delivery of α-synuclein in human APOE-targeted replacement mice expressing APOE2, APOE3, or APOE4. We found that APOE4, but not APOE2 or APOE3, increased α-synuclein pathology, impaired behavioral performances, worsened neuronal and synaptic loss, and increased astrogliosis at 9 months of age. Transcriptomic profiling in APOE4-expressing α-synuclein mice highlighted altered lipid and energy metabolism and synapse-related pathways. We also observed an effect of APOE4 on α-synuclein pathology in human postmortem brains with LBD and minimal amyloid pathology. Our data demonstrate a pathogenic role of APOE4 in exacerbating α-synuclein pathology independent of amyloid, providing mechanistic insights into how APOE4 increases the risk of LBD.
Asunto(s)
Apolipoproteína E4 , Enfermedad por Cuerpos de Lewy/genética , Sinucleinopatías , alfa-Sinucleína , Péptidos beta-Amiloides , Animales , Apolipoproteína E4/genética , Ratones , Ratones Noqueados para ApoE , Sinucleinopatías/genéticaRESUMEN
Apolipoprotein E (APOE) ε4 allele is the strongest genetic risk factor for late-onset Alzheimer's disease mainly by modulating amyloid-ß pathology. APOE ε4 is also shown to exacerbate neurodegeneration and neuroinflammation in a tau transgenic mouse model. To further evaluate the association of APOE genotype with the presence and severity of tau pathology, we express human tau via an adeno-associated virus gene delivery approach in human APOE targeted replacement mice. We find increased hyperphosphorylated tau species, tau aggregates, and behavioral abnormalities in mice expressing APOE ε2/ε2. We also show that in humans, the APOE ε2 allele is associated with increased tau pathology in the brains of progressive supranuclear palsy (PSP) cases. Finally, we identify an association between the APOE ε2/ε2 genotype and risk of tauopathies using two series of pathologically-confirmed cases of PSP and corticobasal degeneration. Our data together suggest APOE ε2 status may influence the risk and progression of tauopathy.
