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.
Identification of a chronic non-neurodegenerative microglia activation state in a mouse model of peroxisomal β-oxidation deficiency.
Sex, Age, Specimen part
View SamplesPrevious studies have reported that microglia depletion leads to impairment of synapse formation and these cells rapidly repopulate from CNS progenitors. However, the impact of microglia depletion and repopulation on the long-term state of the CNS environment has not been characterized. Here, we found by RNA-seq analysis that acute and synchronous microglia depletion results in a type 1-interferon inflammatory signature in degenerating somatosensory cortex in microglia-depleted mice. Transcriptomic and mass cytometry analysis of repopulated microglia demonstrates an interferon regulatory factor 7-driven activation state. Minocycline and anti-IFNAR1 antibody treatment attenuate the CNS type-1 interferon-driven inflammation and restore microglia homeostasis. Together, we found that acute microglia ablation induces a type-1 interferon activation state of grey matter microglia associated with acute neurodegeneration. Overall design: RNAseq analysis of brain cortical tissue from control and microglia-depleted mice.
Acute microglia ablation induces neurodegeneration in the somatosensory system.
Specimen part, Subject
View SamplesAmyotrophic lateral sclerosis (ALS) is a paralytic degenerative disease of the nervous system. In the SOD1 mouse model of ALS we found loss of the molecular and functional microglia signature associated with pronounced expression of miR-155 in SOD1 mice. We also found increased expression of miR-155 in the spinal cord of ALS subjects. Genetic ablation of miR-155 increased survival in SOD1 mice and reversed the abnormal microglial and monocyte molecular signature. In addition, dysregulated proteins in the spinal cord of SOD1 mice that we identified in human ALS spinal cords and CSF were restored in SOD1G93A/miR155-/- mice. Treatment of SOD1 mice with anti-miR-155 SOD1 mice injected systemically or into the cerebrospinal fluid prolonged survival and restored the microglial unique genetic and microRNA profiles. Our findings provide a new avenue for immune based therapy of ALS by targeting miR-155. Overall design: Total RNA was isolated from whole lumbar spinal cord homogenate from healthy control donors without known neurologic diseases and sporadic and familial ALS.
Targeting miR-155 restores abnormal microglia and attenuates disease in SOD1 mice.
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View SamplesMicroglia 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. Overall design: Illumina NextSeq500 was used to identify disease-associated vs. homeostatic molecular microglia signature in microglia in different disease models and transgenic models. Bulk microglia (1,000 cells/sample) FCRLS+ sorted microglia.
The TREM2-APOE Pathway Drives the Transcriptional Phenotype of Dysfunctional Microglia in Neurodegenerative Diseases.
Specimen part, Cell line, Subject
View SamplesMicroglia 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. Overall design: Illumina NextSeq500 was used to identify disease-associated vs. homeostatic molecular microglia signature in microglia in different disease models and transgenic models. Bulk microglia (1,000 cells/sample) FCRLS+ sorted microglia.
The TREM2-APOE Pathway Drives the Transcriptional Phenotype of Dysfunctional Microglia in Neurodegenerative Diseases.
Sex, Specimen part, Cell line, Subject
View SamplesGlioblastoma is the most common primary malignant brain tumor in adults and associated with poor survival. Standard-of-care chemotherapy and radiation confer a median overall survival of under two years. The Ivy Foundation Early Phase Clinical Trials Consortium conducted a randomized, multi institution clinical trial to evaluate immune responses and survival following neoadjuvant and/or adjuvant therapy with pembrolizumab, a programmed cell death protein 1 (PD-1) monoclonal antibody, in 35 patients with recurrent, surgically resectable glioblastoma. Patients who were randomized to receive neoadjuvant pembrolizumab, with continued adjuvant therapy following surgery, had significantly extended overall survival compared to patients that were randomized to receive adjuvant, post-surgical PD-1 blockade alone (hazard ratio = 0.39; P = 0.04, log-rank test). Neoadjuvant PD-1 blockade was associated with upregulation of T cell and interferon-?-related genes, but downregulation of cell cycle related genes within the tumor, which was not seen in patients that received adjuvant therapy alone. Focal induction of programmed death-ligand 1 (PD-L1) in the tumor microenvironment was observed more frequently in the neoadjuvant group than in tumors obtained from patients treated only in the adjuvant setting. Similarly, neoadjuvant pembrolizumab was associated with clonal T cell expansion and the overlap of T cell receptors between tumor and blood, decreased PD-1 expression in T cells and a decreasing peripheral monocytic population. These findings suggest that the neoadjuvant administration of PD-1 blockade enhances the local and systemic anti-tumor immune response and may represent a more efficacious approach to the treatment of this uniformly lethal brain tumor. This trial was registered with ClinicalTrials.gov under the identifier NCT02852655 (https://clinicaltrials.gov/ct2/show/NCT02852655). Overall design: This dataset contains the transcriptomes of recurrent glioblastoma with either neoadjuvant (1 dose) or adjuvant pembrolizumab treatment
Neoadjuvant anti-PD-1 immunotherapy promotes a survival benefit with intratumoral and systemic immune responses in recurrent glioblastoma.
Subject
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