Single-nucleus RNA sequencing of dorsolateral prefrontal cortex from normal, pathological aging, and Alzheimer’s disease human brains
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ABSTRACT: We performed single-nucleus RNA sequencing of the dorsolateral prefrontal cortex from 15 normal, pathological aging, and Alzheimer’s disease human brains that varied by APOE and TREM2 genotype to analyze cell-type specific transcriptomic changes across the range of Alzheimer’s disease pathology and genetic risk factors.
Project description:Single-nucleus RNA sequencing of dorsolateral prefrontal cortex from normal, pathological aging, and Alzheimer’s disease human brains
Project description:Variations in many genes linked to sporadic Alzheimer’s disease (AD), show abundant expression in microglia, however, relationships between these genes remain largely elusive. Here, we establish isogenic human ES-derived microglia-like cell lines (hMGLs) harboring AD variants in CD33, INPP5D, SORL1 and TREM2 loci, and curate a comprehensive atlas comprising ATACseq, ChIPseq, RNAseq and proteomics datasets. AD-like expression signatures are observed in AD mutant SORL1 and TREM2 hMGLs, while integrative multi-omic analysis of combined epigenetic and expression datasets indicates upregulation of APOE as a convergent pathogenic node. We also observe cross-regulatory relationships between SORL1 and TREM2, where SORL1R744X hMGLs induce TREM2 expression to enhance APOE expression. AD-associated SORL1 and TREM2 mutations also impaired hMGL Aβ uptake in an APOE-dependent manner in vitro, and attenuated Aβ uptake/clearance in mouse AD brain xenotransplants. Utilizing this modeling and analysis platform for human microglia, we provide new insight into epistatic interactions in AD genes and demonstrate convergence of microglial AD genes at the APOE locus.
Project description:Variations in many genes linked to sporadic Alzheimer’s disease (AD), show abundant expression in microglia, however, relationships between these genes remain largely elusive. Here, we establish isogenic human ES-derived microglia-like cell lines (hMGLs) harboring AD variants in CD33, INPP5D, SORL1 and TREM2 loci, and curate a comprehensive atlas comprising ATACseq, ChIPseq, RNAseq and proteomics datasets. AD-like expression signatures are observed in AD mutant SORL1 and TREM2 hMGLs, while integrative multi-omic analysis of combined epigenetic and expression datasets indicates upregulation of APOE as a convergent pathogenic node. We also observe cross-regulatory relationships between SORL1 and TREM2, where SORL1R744X hMGLs induce TREM2 expression to enhance APOE expression. AD-associated SORL1 and TREM2 mutations also impaired hMGL Aβ uptake in an APOE-dependent manner in vitro, and attenuated Aβ uptake/clearance in mouse AD brain xenotransplants. Utilizing this modeling and analysis platform for human microglia, we provide new insight into epistatic interactions in AD genes and demonstrate convergence of microglial AD genes at the APOE locus.
Project description:Variations in many genes linked to sporadic Alzheimer’s disease (AD), show abundant expression in microglia, however, relationships between these genes remain largely elusive. Here, we establish isogenic human ES-derived microglia-like cell lines (hMGLs) harboring AD variants in CD33, INPP5D, SORL1 and TREM2 loci, and curate a comprehensive atlas comprising ATACseq, ChIPseq, RNAseq and proteomics datasets. AD-like expression signatures are observed in AD mutant SORL1 and TREM2 hMGLs, while integrative multi-omic analysis of combined epigenetic and expression datasets indicates upregulation of APOE as a convergent pathogenic node. We also observe cross-regulatory relationships between SORL1 and TREM2, where SORL1R744X hMGLs induce TREM2 expression to enhance APOE expression. AD-associated SORL1 and TREM2 mutations also impaired hMGL Aβ uptake in an APOE-dependent manner in vitro, and attenuated Aβ uptake/clearance in mouse AD brain xenotransplants. Utilizing this modeling and analysis platform for human microglia, we provide new insight into epistatic interactions in AD genes and demonstrate convergence of microglial AD genes at the APOE locus.
Project description:Microglia play important roles in maintaining brain homeostasis. The discovery of genetic variants in the genes encoding Apolipoprotein E (APOE) and triggering receptor expressed on myeloid cells 2 (TREM2) as the strongest risk factors for Alzheimer’s disease (AD) highlights the importance of microglial biology in the brain. The sequence, structure and function of microglial proteins are poorly conserved across species, and this hampered the development of APOE and TREM2 targeting therapeutic strategies. One way to target APOE and TREM2 is to modulate their expression using antisense oligonucleotides (ASOs). In this study, we identified ASOs that selectively and potently reduce human APOE and TREM2 levels in human myeloid cells including iPSC-derived microglia. We demonstrated that a single bolus delivery of the ASOs in the mouse cerebrospinal fluid (CSF) is sufficient for the ASO to be pharmacologically active and modify the phenotype of xenografted human microglia throughout the mouse brain for at least 4 weeks. This study is the first proof-of-concept that the expression of microglial genes can be modulated using ASOs in a dose-dependent manner in order to manipulate human microglia phenotypes in vivo, and demonstrates the utility of these ASOs both as research and therapeutic tools to modulate neuroinflammation.
Project description:Microglia play a pivotal role in the maintenance of brain homeostasis, but lose their homeostatic function during the course of neurodegenerative disorders. We identified a specific APOE-dependent molecular signature in microglia isolated from mouse models of amyotrophic lateral sclerosis, multiple sclerosis and Alzheimer’s disease (SOD1, EAE and APP-PS1) and in microglia surrounding neuritic A-plaques in human Alzheimer’s disease brain. This is mediated by a switch from a (M0)-homeostatic to (MGnD)-neurodegenerative phenotype following phagocytosis of apoptotic neurons via the TREM2-APOE pathway. TREM2 induces APOE signaling which is a negative regulator of the transcription program in M0-homeostatic microglia. Targeting the TREM2-APOE pathway restores the M0-homeostatic signature of microglia in APP-PS1 and SOD1 mice and prevents from neuronal loss in an acute model of neurodegeneration. In SOD1 mice, TREM2 regulates MGnD in a gender-dependent manner. APOE-mediated MGnD microglia lose their tolerogenic function. Taken together, our work identifies the TREM2-APOE pathway as a major regulator of microglial functional phenotype in neurodegenerative diseases and serves as a novel target to restore homeostatic microglia.
Project description:Microglia play a pivotal role in the maintenance of brain homeostasis, but lose their homeostatic function during the course of neurodegenerative disorders. We identified a specific APOE-dependent molecular signature in microglia isolated from mouse models of amyotrophic lateral sclerosis, multiple sclerosis and Alzheimer’s disease (SOD1, EAE and APP-PS1) and in microglia surrounding neuritic A-plaques in human Alzheimer’s disease brain. This is mediated by a switch from a (M0)-homeostatic to (MGnD)-neurodegenerative phenotype following phagocytosis of apoptotic neurons via the TREM2-APOE pathway. TREM2 induces APOE signaling which is a negative regulator of the transcription program in M0-homeostatic microglia. Targeting the TREM2-APOE pathway restores the M0-homeostatic signature of microglia in APP-PS1 and SOD1 mice and prevents from neuronal loss in an acute model of neurodegeneration. In SOD1 mice, TREM2 regulates MGnD in a gender-dependent manner. APOE-mediated MGnD microglia lose their tolerogenic function. Taken together, our work identifies the TREM2-APOE pathway as a major regulator of microglial functional phenotype in neurodegenerative diseases and serves as a novel target to restore homeostatic microglia.
Project description:Microglia play a pivotal role in the maintenance of brain homeostasis, but lose their homeostatic function during the course of neurodegenerative disorders. We identified a specific APOE-dependent molecular signature in microglia isolated from mouse models of amyotrophic lateral sclerosis, multiple sclerosis and Alzheimer’s disease (SOD1, EAE and APP-PS1) and in microglia surrounding neuritic A-plaques in human Alzheimer’s disease brain. This is mediated by a switch from a (M0)-homeostatic to (MGnD)-neurodegenerative phenotype following phagocytosis of apoptotic neurons via the TREM2-APOE pathway. TREM2 induces APOE signaling which is a negative regulator of the transcription program in M0-homeostatic microglia. Targeting the TREM2-APOE pathway restores the M0-homeostatic signature of microglia in APP-PS1 and SOD1 mice and prevents from neuronal loss in an acute model of neurodegeneration. In SOD1 mice, TREM2 regulates MGnD in a gender-dependent manner. APOE-mediated MGnD microglia lose their tolerogenic function. Taken together, our work identifies the TREM2-APOE pathway as a major regulator of microglial functional phenotype in neurodegenerative diseases and serves as a novel target to restore homeostatic microglia.
Project description:Reduced representation bisulfite sequencing (RRBS) was conducted on dorsolateral prefrontal cortex tissue samples taken from the brains of control individuals not affected by neurological disorder DNA methylation profiling was conducted using RRBS and the Illumina Genome Analyzer IIx
Project description:Microglia play a pivotal role in the maintenance of brain homeostasis, but lose their homeostatic function during the course of neurodegenerative disorders. We identified a specific APOE-dependent molecular signature in microglia isolated from mouse models of amyotrophic lateral sclerosis, multiple sclerosis and Alzheimer’s disease (SOD1, EAE and APP-PS1) and in microglia surrounding neuritic A-plaques in human Alzheimer’s disease brain. This is mediated by a switch from a (M0)-homeostatic to (MGnD)-neurodegenerative phenotype following phagocytosis of apoptotic neurons via the TREM2-APOE pathway. TREM2 induces APOE signaling which is a negative regulator of the transcription program in M0-homeostatic microglia. Targeting the TREM2-APOE pathway restores the M0-homeostatic signature of microglia in APP-PS1 and SOD1 mice and prevents from neuronal loss in an acute model of neurodegeneration. In SOD1 mice, TREM2 regulates MGnD in a gender-dependent manner. APOE-mediated MGnD microglia lose their tolerogenic function. Taken together, our work identifies the TREM2-APOE pathway as a major regulator of microglial functional phenotype in neurodegenerative diseases and serves as a novel target to restore homeostatic microglia. MG550 custom-design Nanosting chips were used to identify disease-associated vs. homeostatic molecular microglia signature in microglia in different disease models and transgenic models.