Long term effects of COP1 deletion in microglia in vivo
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE145446 | GEO | 2020/08/14
REPOSITORIES: GEO
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Project description:Dysregulated microglia are intimately involved in neurodegeneration including Alzheimer’s disease (AD) pathogenesis, but the mechanisms controlling pathogenic microglial gene expression remain poorly understood. The transcription factor CCAAT/enhancer binding protein beta (c/EBPß) regulates pro-inflammatory genes in microglia and is upregulated in AD. We show expression of c/EBPß in microglia is regulated post-translationally by the ubiquitin ligase COP1 (also called RFWD2). Ubiquitination of c/EBPß by COP1 targets it for proteasomal degradation. In the absence of COP1, c/EBPß accumulates rapidly and drives a potent pro-inflammatory and ApoE gene-expression program, evidenced by increased neurotoxicity in microglia-neuronal co-cultures. Antibody blocking studies reveal that neurotoxicity is almost entirely attributable to complement. Remarkably, loss of a single allele of Cebpb prevented the pro-inflammatory phenotype. COP1-deficient microglia markedly accelerated tau-mediated neurodegeneration in a mouse model where elevated ApoE plays a deleterious role. Collectively, these results identify c/EBPß as a potential therapeutic target for inflammation-driven neurodegeneration.
2020-08-14 | GSE145454 | GEO
Project description:The realization in the last decade that dysregulated microglia are intimately involved in Alzheimer’s disease (AD) pathogenesis has been a major advance. The precise mechanisms controlling pathogenic programs of microglia gene expression, however, remain poorly understood. The transcription factor (TF) c/EBPß is highly expressed in microglia and is known to regulate expression of pro-inflammatory genes. Notably, c/EBPß is upregulated in AD. Despite mounting evidence that the levels of this pivotal pro-inflammatory TF are tightly regulated, how this is achieved is unclear as alterations in its levels are not reflected in transcript levels. Remarkably, we find that this TF is primarily regulated post-translationally. Here we show that the ubiquitin ligase Cop1 functions as a “brake” on microglial activation by targeting C/EBPß for ubiquitination and subsequent proteasomal mediated degradation. In the absence of Cop1, C/EBPß protein rapidly and dramatically accumulates leading to engagement of a potent pro-inflammatory and ApoE gene-expression program, evidenced by increased neurotoxicity in microglia-neuronal co-cultures. Antibody blocking studies revealed that the neurotoxicity was almost entirely attributable to complement. Unexpectedly, loss of a single allele of C/EBPß, rescued the pro-inflammatory phenotype underscoring a significant gene dosage effect. We also found that Cop1 deletion accelerated a mouse model of tau-mediated neurodegeneration where elevated ApoE plays a deleterious role. Taken together these results point to C/EBPß as a potential therapeutic target for inflammation-driven neurodegeneration as the heterozygote animal is otherwise normal.
2020-08-14 | GSE145445 | GEO
Project description:The realization in the last decade that dysregulated microglia are intimately involved in Alzheimer’s disease (AD) pathogenesis has been a major advance. The precise mechanisms controlling pathogenic programs of microglia gene expression, however, remain poorly understood. The transcription factor (TF) c/EBPß is highly expressed in microglia and is known to regulate expression of pro-inflammatory genes. Notably, c/EBPß is upregulated in AD. Despite mounting evidence that the levels of this pivotal pro-inflammatory TF are tightly regulated, how this is achieved is unclear as alterations in its levels are not reflected in transcript levels. Remarkably, we find that this TF is primarily regulated post-translationally. Here we show that the ubiquitin ligase Cop1 functions as a “brake” on microglial activation by targeting C/EBPß for ubiquitination and subsequent proteasomal mediated degradation. In the absence of Cop1, C/EBPß protein rapidly and dramatically accumulates leading to engagement of a potent pro-inflammatory and ApoE gene-expression program, evidenced by increased neurotoxicity in microglia-neuronal co-cultures. Antibody blocking studies revealed that the neurotoxicity was almost entirely attributable to complement. Unexpectedly, loss of a single allele of C/EBPß, rescued the pro-inflammatory phenotype underscoring a significant gene dosage effect. We also found that Cop1 deletion accelerated a mouse model of tau-mediated neurodegeneration where elevated ApoE plays a deleterious role. Taken together these results point to C/EBPß as a potential therapeutic target for inflammation-driven neurodegeneration as the heterozygote animal is otherwise normal.
2020-08-14 | GSE145444 | GEO
Project description:The realization in the last decade that dysregulated microglia are intimately involved in Alzheimer’s disease (AD) pathogenesis has been a major advance. The precise mechanisms controlling pathogenic programs of microglia gene expression, however, remain poorly understood. The transcription factor (TF) c/EBPß is highly expressed in microglia and is known to regulate expression of pro-inflammatory genes. Notably, c/EBPß is upregulated in AD. Despite mounting evidence that the levels of this pivotal pro-inflammatory TF are tightly regulated, how this is achieved is unclear as alterations in its amounts are not reflected in transcript levels. Remarkably, we find that this TF is primarily regulated post-translationally. Here we show that the ubiquitin ligase Cop1 functions as a “brake” on microglial activation by targeting c/EBPß for ubiquitination and subsequent proteasomal mediated degradation. In the absence of Cop1, c/EBPß protein rapidly and dramatically accumulates leading to engagement of a potent pro-inflammatory and ApoE gene-expression program, evidenced by increased neurotoxicity in microglia-neuronal co-cultures. Antibody blocking studies revealed that the neurotoxicity was almost entirely attributable to complement. Unexpectedly, loss of a single allele of c/EBPß, rescued the pro-inflammatory phenotype underscoring a significant gene dosage effect. We also found that Cop1 deletion accelerated disease progression in a mouse model of tau-mediated neurodegeneration where elevated ApoE plays a deleterious role. Taken together these results point to c/EBPß as a potential therapeutic target for inflammation-driven neurodegeneration as the heterozygote animal is otherwise normal.
2020-08-14 | GSE151845 | GEO
Project description:The realization in the last decade that dysregulated microglia are intimately involved in Alzheimer’s disease (AD) pathogenesis has been a major advance. The precise mechanisms controlling pathogenic programs of microglia gene expression, however, remain poorly understood. The transcription factor (TF) c/EBPß is highly expressed in microglia and is known to regulate expression of pro-inflammatory genes. Notably, c/EBPß is upregulated in AD. Despite mounting evidence that the levels of this pivotal pro-inflammatory TF are tightly regulated, how this is achieved is unclear as alterations in its amounts are not reflected in transcript levels. Remarkably, we find that this TF is primarily regulated post-translationally. Here we show that the ubiquitin ligase Cop1 functions as a “brake” on microglial activation by targeting c/EBPß for ubiquitination and subsequent proteasomal mediated degradation. In the absence of Cop1, c/EBPß protein rapidly and dramatically accumulates leading to engagement of a potent pro-inflammatory and ApoE gene-expression program, evidenced by increased neurotoxicity in microglia-neuronal co-cultures. Antibody blocking studies revealed that the neurotoxicity was almost entirely attributable to complement. Unexpectedly, loss of a single allele of c/EBPß, rescued the pro-inflammatory phenotype underscoring a significant gene dosage effect. We also found that Cop1 deletion accelerated disease progression in a mouse model of tau-mediated neurodegeneration where elevated ApoE plays a deleterious role. Taken together these results point to c/EBPß as a potential therapeutic target for inflammation-driven neurodegeneration as the heterozygote animal is otherwise normal.
2020-08-14 | GSE147559 | GEO
Project description:The realization in the last decade that dysregulated microglia are intimately involved in Alzheimer’s disease (AD) pathogenesis has been a major advance. The precise mechanisms controlling pathogenic programs of microglia gene expression, however, remain poorly understood. The transcription factor (TF) c/EBPß is highly expressed in microglia and is known to regulate expression of pro-inflammatory genes. Notably, c/EBPß is upregulated in AD. Despite mounting evidence that the levels of this pivotal pro-inflammatory TF are tightly regulated, how this is achieved is unclear as alterations in its amounts are not reflected in transcript levels. Remarkably, we find that this TF is primarily regulated post-translationally. Here we show that the ubiquitin ligase Cop1 functions as a “brake” on microglial activation by targeting c/EBPß for ubiquitination and subsequent proteasomal mediated degradation. In the absence of Cop1, c/EBPß protein rapidly and dramatically accumulates leading to engagement of a potent pro-inflammatory and ApoE gene-expression program, evidenced by increased neurotoxicity in microglia-neuronal co-cultures. Antibody blocking studies revealed that the neurotoxicity was almost entirely attributable to complement. Unexpectedly, loss of a single allele of c/EBPß, rescued the pro-inflammatory phenotype underscoring a significant gene dosage effect. We also found that Cop1 deletion accelerated disease progression in a mouse model of tau-mediated neurodegeneration where elevated ApoE plays a deleterious role. Taken together these results point to c/EBPß as a potential therapeutic target for inflammation-driven neurodegeneration as the heterozygote animal is otherwise normal.
2020-08-14 | GSE147558 | GEO
Project description:The realization in the last decade that dysregulated microglia are intimately involved in Alzheimer’s disease (AD) pathogenesis has been a major advance. The precise mechanisms controlling pathogenic programs of microglia gene expression, however, remain poorly understood. The transcription factor (TF) c/EBPß is highly expressed in microglia and is known to regulate expression of pro-inflammatory genes. Notably, c/EBPß is upregulated in AD. Despite mounting evidence that the levels of this pivotal pro-inflammatory TF are tightly regulated, how this is achieved is unclear as alterations in its amounts are not reflected in transcript levels. Remarkably, we find that this TF is primarily regulated post-translationally. Here we show that the ubiquitin ligase Cop1 functions as a “brake” on microglial activation by targeting c/EBPß for ubiquitination and subsequent proteasomal mediated degradation. In the absence of Cop1, c/EBPß protein rapidly and dramatically accumulates leading to engagement of a potent pro-inflammatory and ApoE gene-expression program, evidenced by increased neurotoxicity in microglia-neuronal co-cultures. Antibody blocking studies revealed that the neurotoxicity was almost entirely attributable to complement. Unexpectedly, loss of a single allele of c/EBPß, rescued the pro-inflammatory phenotype underscoring a significant gene dosage effect. We also found that Cop1 deletion accelerated disease progression in a mouse model of tau-mediated neurodegeneration where elevated ApoE plays a deleterious role. Taken together these results point to c/EBPß as a potential therapeutic target for inflammation-driven neurodegeneration as the heterozygote animal is otherwise normal.
2020-08-14 | GSE147557 | GEO
Project description:Microglia are innate immune cells of the brain that perform phagocytic and inflammatory functions in disease conditions. Transcriptomic studies of acutely-isolated microglia have provided novel insights into their molecular and functional diversity in homeostatic and neurodegenerative disease states. State-of-the-art mass spectrometric methods can comprehensively characterize proteomic alterations in microglia in neurodegenerative disorders, potentially providing novel functionally-relevant molecular insights that are not provided by transcriptomics. However, proteomic profiling of adult primary microglia in neurodegenerative disease conditions has not been performed. We performed quantitative proteomic analyses of purified CD11b+ acutely-isolated microglia adult mice in normal, acute neuroinflammatory (LPS-treatment) and chronic neurodegenerative states (5xFAD model of Alzheimer’s disease [AD]) using tandem mass tag mass spectrometry. Differential expression analyses were performed to characterize specific microglial proteomic changes in 5xFAD mice and identify overlap with LPS-induced pro-inflammatory changes. Our results were also contrasted with existing proteomic data from wild-type mouse microglia and from existing microglial transcriptomic data from wild-type and 5xFAD mice. Neuropathological validation studies of select proteins were performed in human AD and 5xFAD brains. Of 4,133 proteins identified, 187 microglial proteins were differentially expressed in the 5xFAD mouse model of AD pathology, including proteins with previously known (Apoe, Clu and Htra1) as well as previously unreported relevance to AD biology (Cotl1 and Hexb). Proteins upregulated in 5xFAD microglia shared significant overlap with pro-inflammatory changes observed in LPS-treated mice. Several proteins increased in human AD brain were also upregulated by 5xFAD microglia (Aβ peptide, Apoe, Htra1, Cotl1 and Clu). Cotl1 was identified as a novel microglia-specific marker with increased expression and strong association with AD neuropathology. Apoe protein was also detected within plaque-associated microglia in which Apoe and Aβ were highly co-localized suggesting a role for Apoe in phagocytic clearance of Aβ. We report the first comprehensive comparative proteomic study of adult mouse microglia derived from acute neuroinflammatory and AD models, representing a valuable resource to the neuroscience research community. We highlight shared and unique microglial proteomic changes in acute neuroinflammatory, aging and AD mouse models in addition to identifying novel roles for microglial proteins in human neurodegeneration.
2018-09-18 | PXD009137 | Pride
Project description:Purpose: We purified whole brain microglia of MFP2 knockout mice and control mice utilizing percoll gradient and FACS sorting, followed by microarray analysis to define the molecular changes in MFP2 knockout mice at the endstage of the disease. We compared the microglia transcriptome of Mfp2-/- microglia to that of SOD1-G93A microglia isolated from spinal cord to define the microglia signature associated with a non-neurodegenerative environment. Results and conclusions: Mfp2-/- microglia acquire an activation state characterized by activation of mammalian target of rapamycin (mTOR). In addition, activated microglia display reduced expression of genes that are normally highly expressed by surveillant microglia in steady-state conditions. The immunological profile of is heterogeneous and encompasses upregulation of both pro- and anti-inflammatory genes. In contrast to the neurodegeneration-specific microglia profile in SOD1-G93A mice, Mfp2-/- microglia do not induce genes associated with phagocytosis, lysosomal activation and neurotoxicity. 4 MFP2 knockout and 4 control samples were subjected to microarray analysis.
2015-04-14 | E-GEOD-66420 | biostudies-arrayexpress
Project description:In addition to tau and Aβ pathologies, inflammation plays an important role in Alzheimer's disease (AD). Variants in APOE and TREM2 increase AD risk. ApoE4 exacerbates tau-linked neurodegeneration and inflammation in P301S tau mice and removal of microglia blocks tau-dependent neurodegeneration. Microglia adopt a heterogeneous population of transcriptomic states in response to pathology, at least some of which are dependent on TREM2. Previously, we reported that knockout (KO) of TREM2 attenuated neurodegeneration in P301S mice that express mouse Apoe. Because of the possible common pathway of ApoE and TREM2 in AD, we tested whether TREM2 KO (T2KO) would block neurodegeneration in P301S Tau mice expressing ApoE4 (TE4), similar to that observed with microglial depletion. Surprisingly, we observed exacerbated neurodegeneration and tau pathology in TE4-T2KO versus TE4 mice, despite decreased TREM2-dependent microgliosis. Our results suggest that tau pathology-dependent microgliosis, that is, TREM2-independent microgliosis, facilitates tau-mediated neurodegeneration in the presence of ApoE4.
2022-11-30 | GSE206368 | GEO