Defining the microglia transcriptome during disease progression in ALS transgenic mice
Ontology highlight
ABSTRACT: Purpose: We purified spinal cord microglia utilizing percoll gradients and magnetic beads, followed by transcriptome profiling (RNA-seq) to define microglia expression profiles against other neural, immune cell-types. We next observed how the microglai transcriptomes change during activation in the SOD1-G93A mouse model of motor neuron degeneration at 3 timepoints. We also compared these profiles with that induced by LPS injection. Results and conclusions: ALS microglia were found to differ substantially from those activated by LPS and from M1/M2 macrophages by comparison with published datasets. These ALS microglia showing substantial induction of a "neurodegeneration-tailored phenotype", with induction of lysosomal, RNA splicing, and Alzheimer's disease pathway genes. Overall they express a mixture of neuroprotective and neurotoxic factors during activation in ALS mice, showing that neuro-immune activation in the spinal cord is a double-edged sword. We also detected the transcriptional nature of surface marker expression in microglia (CD11b, CD86, CD11c), and substantial T-cell microglia cross-talk using correlative microglia transcriptome/FACS analysis.
Project description:Purpose: We purified spinal cord microglia utilizing percoll gradients and magnetic beads, followed by transcriptome profiling (RNA-seq) to define microglia expression profiles against other neural, immune cell-types. We next observed how the microglial transcriptomes change during activation in the SOD1-G93A mouse model of motor neuron degeneration at 3 time points. We also compared these profiles with that induced by LPS injection. Results and conclusions: ALS microglia were found to differ substantially from those activated by LPS and from M1/M2 macrophages by comparison with published datasets. These ALS microglia showing substantial induction of a neurodegeneration-tailored phenotype, with induction of lysosomal, RNA splicing, and Alzheimer's disease pathway genes. Overall they express a mixture of neuroprotective and neurotoxic factors during activation in ALS mice, showing that neuro-immune activation in the spinal cord is a double-edged sword. We also detected the transcriptional nature of surface marker expression in microglia (CD11b, CD86, CD11c), and substantial T-cell microglia cross-talk using correlative microglia transcriptome/FACS analysis. 42 total RNA samples from purified spinal cord microglia were subjected to paired-end RNA-sequencing. Parallel flow cytometry data was collected from the same spinal cords.
Project description:We investigated the innate immune system in the SOD1 ALS model. We found that splenic Ly6CHi monocytes were activated and their progressive recruitment to the spinal cord, but not brain, correlated with neuronal loss. We found a decrease in resident microglia in the spinal cord with disease progression. Two months prior to disease onset, splenic Ly6CHi monocytes had an M1 signature which included increased CCR2. At one month prior to disease onset, microglia expressed increased CCL2 and other chemotaxis-associated molecules. Microglia derived from the spinal cord of SOD1 mice recruited Ly6C+ monocytes to the CNS. Treatment with anti-Ly6C mAb modulated the Ly6CHi monocyte cytokine profile, reduced monocyte recruitment to the spinal cord, diminished neuronal loss and extended survival. In humans with ALS, CD14+/CD16- monocytes (analogue of Ly6CHi monocytes) exhibited an ALS specific microRNA inflammatory signature similar to that observed in the SOD1 mouse providing a direct link between the animal model and the human disease. Thus, the SOD1-like profile of monocytes in ALS subjects may serve as a biomarker for disease stage or progression. Our results suggest that recruitment of inflammatory monocytes plays an important role in disease progression and that modulation of these cells is a potential therapeutic approach. This study used the NanoString nCounter hybridization system and nCounter miRNA expression assays to identify and quantitate miRNAs in blood CD14+CD16- monocytes from ALS, MS and HC subjects Total RNA was isolated from FACS sorted CD14+CD16- blood-derived monocytes from sporadic ALS (n=8), MS (n=8) and HC (n=8) subjects. RNA was profiled using the NanoString nCounter miRNA expression assay
Project description:Amyotrophic 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. Total RNA was isolated from whole lumbar spinal cord homogenate from healthy control donors without known neurologic diseases and sporadic and familial ALS.
Project description:Combining proteomics and systems biology analyses, we demonstrated that neonatal microglial cells derived from two different CNS locations (cortex and spinal cord) displayed different phenotypes upon different physiological or pathological conditions. These cells also exhibited great variability in terms of both cellular and small extracellular vesicles (sEVs) protein contents and levels. Bioinformatics data analysis showed that the cortical microglia had anti-inflammatory and neurogenesis/tumorigenesis properties, while the spinal cord microglia was rather involved in inflammatory response process. Of interest, while both sEVs microglia sources enhanced growth of DRGs axons, only the spinal cord-derived sEVs microglia under LPS stimulation significantly attenuated glioma proliferation. These results were confirmed through neurite outgrowth assays in DRGs cell line and glioma proliferation analysis in 3D spheroid cultures. Results from these in vitro assays indicated that the microglia localized at different CNS regions can ensure different biological functions. Together, these works indicate that neonatal microglia locations regulate their physiological and pathological functional fates, and could explain the high prevalence of brain vs. spinal cord glioma in adults.
Project description:Background: Microglia play crucial roles in mediating neuronal homeostasis but have been implicated in contributing to amyotrophic lateral sclerosis (ALS). However, the role of microglia in ALS remains incompletely understood. Methods: Here, we generated highly enriched cultures of VCP mutant microglia derived from human induced pluripotent stem cells (hiPSCs) to investigate their cell autonomous and non-cell autonomous roles in ALS pathogenesis. We used RNA-sequencing, proteomics and functional assays to study hiPSC derived VCP mutant microglia and their effects on hiPSC derived motor neurons and astrocytes. Results: Transcriptomic, proteomic and functional analyses revealed immune and lysosomal dysfunction in VCP mutant microglia. Stimulating healthy microglia with inflammatory inducer lipopolysaccharide (LPS) showed partial overlap with VCP mutant microglia in their reactive transformation. LPS-stimulated VCP mutant microglia displayed differential activation of inflammatory pathways compared with LPS-stimulated healthy microglia. Conserved gene expression changes were identified between VCP mutant microglia, SOD1 mutant mice microglia, and postmortem ALS spinal cord microglial signatures, including increased expression of the transmembrane glycoprotein GPNMB. While knockdown of GPNMB affected inflammatory and phagocytosis processes in microglia, this was not sufficient to ameliorate cell autonomous phenotypes in VCP mutant microglia. Secreted factors from VCP mutant microglia were sufficient to activate the JAK-STAT pathway in hiPSC derived motor neurons and astrocytes. Conclusions: VCP mutant microglia undergo cell autonomous reactive transformation involving immune and lysosomal dysfunction that partially recapitulate key phenotypes of microglia from ALS models and post mortem tissue and are independent of GPNMB. VCP mutant microglia elicit non cell autonomous responses in motor neurons and astrocytes involving the JAK-STAT pathway.
Project description:Amyotrophic 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. Total RNA was isolated from FACS sorted adult FCRLS+ microglia from spinal cords of Non-Tg/miR155+/-, SOD1G93A-miR155+/- and SOD1G93A-miR155–/- mice at the age of 120d. Total RNA was extracted using mirVanaTM miRNA isolation kit (Ambion) according to the manufacturer’s protocol. nCounter Nansotring custom-made MG400 chip was used for gene expression profile
Project description:Amyotrophic 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. Total RNA was isolated from FACS sorted adult FCRLS+ microglia from spinal cords and Ly6CHi splenic monocytes from Non-Tg/miR155+/-, SOD1G93A-miR155+/- and SOD1G93A-miR155–/- mice at the age of 120d. Total RNA was extracted using mirVanaTM miRNA isolation kit (Ambion) according to the manufacturer’s protocol. nCounter Nansotring Mouse miRNA Assay Kit was used for miRNA expression profile
Project description:We investigated the innate immune system in the SOD1 ALS model. We found that splenic Ly6CHi monocytes were activated and their progressive recruitment to the spinal cord, but not brain, correlated with neuronal loss. We found a decrease in resident microglia in the spinal cord with disease progression. Two months prior to disease onset, splenic Ly6CHi monocytes had an M1 signature which included increased CCR2. At one month prior to disease onset, microglia expressed increased CCL2 and other chemotaxis-associated molecules. Microglia derived from the spinal cord of SOD1 mice recruited Ly6C+ monocytes to the CNS. Treatment with anti-Ly6C mAb modulated the Ly6CHi monocyte cytokine profile, reduced monocyte recruitment to the spinal cord, diminished neuronal loss and extended survival. In humans with ALS, CD14+/CD16- monocytes (analogue of Ly6CHi monocytes) exhibited an ALS specific microRNA inflammatory signature similar to that observed in the SOD1 mouse providing a direct link between the animal model and the human disease. Thus, the SOD1-like profile of monocytes in ALS subjects may serve as a biomarker for disease stage or progression. Our results suggest that recruitment of inflammatory monocytes plays an important role in disease progression and that modulation of these cells is a potential therapeutic approach This study used the NanoString nCounter hybridization system and the Nanostring GX Human Immunology and Nanostring Human Inflammation assays to identify and quantitate immune-related genes in blood CD14+CD16- monocytes from ALS, MS and HC subjects Total RNA was isolated from FACS sorted CD14+CD16- blood-derived monocytes from sporadic sALS (n=10), fALS (n=4) and HC (n=10) subjects. RNA was profiled using the Nanostring GX Human Immunology and Nanostring Human Inflammation assays
Project description:Burgeoning evidence highlights seminal roles for microglia in the pathogenesis of neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). The receptor for advanced glycation end products (RAGE) binds ligands relevant to ALS that accumulate in the diseased spinal cord and RAGE has been previously implicated in the progression of ALS pathology. We generated a novel mouse model to temporally delete Ager from microglia in the murine SOD1G93A model of ALS. Microglia Ager deficient SOD1G93A mice and controls were examined for changes in survival, motor function, gliosis, motor neuron numbers, and transcriptomic analyses of lumbar spinal cord. Furthermore, we examined bulk-RNA-sequencing transcriptomic analyses of human ALS cervical spinal cord. Transcriptomic analysis of human cervical spinal cord reveals a range of AGER expression in ALS patients, which was negatively correlated with age at disease onset and death or tracheostomy. The degree of AGER expression related to differential expression of pathways involved in extracellular matrix, lipid metabolism, and intercellular communication. Microglia display increased RAGE immunoreactivity in the spinal cords of high AGER expressing patients and in the SOD1G93A murine model of ALS vs. respective controls. We demonstrate that microglia Ager deletion at the age of symptomatic onset, day 90, in SOD1G93A mice extends survival in male but not female mice. Critically, many of the pathways identified in human ALS patients that accompanied increased AGER expression were significantly ameliorated by microglia Ager deletion in male SOD1G93A mice. Our results indicate that microglia RAGE disrupts communications with cell types including astrocytes and neurons, intercellular communication pathways that divert microglia from a homeostatic to an inflammatory and tissue-injurious program. In totality, microglia RAGE contributes to the progression of SOD1G93A murine pathology in male mice and may be relevant in human disease.
Project description:Microglia and peripheral macrophages, combined, have been implicated in the motor neuron disease Amyotrophic Lateral Sclerosis (ALS), but without discriminating their respective roles. We now show that macrophages along peripheral motor neuron axons of ALS mice and patients react to neurodegeneration. In ALS mice, peripheral myeloid cell infiltration into the spinal cord was limited and disease duration dependent. Targeted gene modulation of the reactive oxygen species pathway in peripheral myeloid cells of ALS mice, using cell replacement, reduced both peripheral macrophage and microglial activation, delayed symptoms and increased ALS mouse survival. Transcriptomics revealed that sciatic nerve macrophages and microglia reacted very different to neurodegeneration, with abrupt temporal changes in macrophages and progressive, unidirectional activation in microglia. Modifying peripheral macrophages suppressed proinflammatory microglial responses, with a strong shift towards neuronal support. Thus, modifying macrophages at the periphery has the capacity to influence disease progression and is of therapeutic value for ALS.