Project description:Myelin abnormalities, oligodendrocyte damage, and concomitant glia activation are common in demyelinating diseases of the central nervous system (CNS). The neurotoxicant cuprizone (CPZ) has been extensively used to create a mouse model of demyelination. However, the changes of miRNA expression and effects on behavior of cuprizone treatment have not been clearly reported. We have analyzed the behavioral changes of mice given a diet containing 0.2% cuprizone for 6 weeks. To evaluate the changes of miRNA expression in CPZ-induced demyelination compared with control, we performed the Affymetrix GeneChip® miRNA 4.0 Array. We identified 1348 and 1253 differentially expressed miRNAs for control and CPZ-treated mice, respectively. Furthermore, the expression of 240 miRNAs was significantly changed in CPZ-induced mice comparing with control mice. These results suggest that the changes of miRNA expression in vivo may provide a new potential remyelination therapeutic target.
Project description:Myelin abnormalities, oligodendrocyte damage, and concomitant glia activation are common in demyelinating diseases of the central nervous system (CNS). The neurotoxicant cuprizone (CPZ) has been extensively used to create a mouse model of demyelination. However, the changes of miRNA expression and effects on behavior of cuprizone treatment have not been clearly reported. We have analyzed the behavioral changes of mice given a diet containing 0.2% cuprizone for 6 weeks. To evaluate the changes of gene expression in CPZ-induced demyelination compared with control, we performed the GeneChip® mouse Gene 2.0 ST Array.
Project description:Demyelination and dysregulated myelination in the CNS are hallmarks of many neurodegenerative diseases such as multiple sclerosis (MS) and leukodystrophies. Here, we studied GFAP+ astrocytes during de- and remyelination in the cuprizone mouse by exploiting the ribosomal tagging (RiboTag) technology. Analyses were performed 5 weeks after cuprizone feeding, at the peak of demyelination in the corpus callosum, and 0.5 and 2 weeks after cuprizone withdrawal, when remyelination and tissue repair is initiated. After 5 weeks of cuprizone feeding, reactive astrocytes showed inflammatory signatures with enhanced expression of genes that modulate leukocyte migration (Tlr2, Cd86, Parp14,Cxcl10). Furthermore, demyelination-induced reactive astrocytes expressed numerous ligands including Cx3cl1, Csf1, Il34, and Gas6 that act on homeostatic as well as activated microglia and thus potentially mediate activation and recruitment of microglia as well as enhancement of their phagocytosis. During early remyelination, region-specific astrocytes displayed reduced inflammatory response signatures as indicated by shut down of CXCL10 production. During late remyelination, the signatures of GFAP+ astrocytes shifted towards resolving inflammation by active suppression of lymphocyte activation and differentiation and support of glia cell differentiation. Astrocytes showed enhanced expression of osteopontin (SPP1) as well as of factors that are relevant for tissue remodelling (Timp1), regeneration and axonal repair. In conclusion, we detected highly dynamic astroglial transcriptomic signatures in the cuprizone model, which reflects excessive communication amongst glia cells and highlights different astrocyte functions during neurodegeneration and regeneration.
Project description:Demyelination and dysregulated myelination in the CNS are hallmarks of many neurodegenerative diseases such as multiple sclerosis (MS) and leukodystrophies. Here, we studied GFAP+ astrocytes during de- and remyelination in the cuprizone mouse by exploiting the ribosomal tagging (RiboTag) technology. Analyses were performed 5 weeks after cuprizone feeding, at the peak of demyelination in the corpus callosum, and 0.5 and 2 weeks after cuprizone withdrawal, when remyelination and tissue repair is initiated. After 5 weeks of cuprizone feeding, reactive astrocytes showed inflammatory signatures with enhanced expression of genes that modulate leukocyte migration (Tlr2, Cd86, Parp14,Cxcl10). Furthermore, demyelination-induced reactive astrocytes expressed numerous ligands including Cx3cl1, Csf1, Il34, and Gas6 that act on homeostatic as well as activated microglia and thus potentially mediate activation and recruitment of microglia as well as enhancement of their phagocytosis. During early remyelination, region-specific astrocytes displayed reduced inflammatory response signatures as indicated by shut down of CXCL10 production. During late remyelination, the signatures of GFAP+ astrocytes shifted towards resolving inflammation by active suppression of lymphocyte activation and differentiation and support of glia cell differentiation. Astrocytes showed enhanced expression of osteopontin (SPP1) as well as of factors that are relevant for tissue remodelling (Timp1), regeneration and axonal repair. In conclusion, we detected highly dynamic astroglial transcriptomic signatures in the cuprizone model, which reflects excessive communication amongst glia cells and highlights different astrocyte functions during neurodegeneration and regeneration.
Project description:How microglia respond and regulate demyelination is not fully understood. To understand how microglia respond during demyelination, we fed mice cuprizone and assessed the response of genetically fate-mapped microglia. Cuprizone-induced demyelination generated a robust microglial response. We conducted single-cell RNA sequencing and identified several cuprizone-associated microglia (CAM) clusters during demyelination. These clusters expressed a transcriptomic signature indicative of cytokine regulation and reactive oxygen species production with altered lysosomal and metabolic changes consistent with ongoing phagocytosis. To understand how microglia contribute to the clearance of dead oligodendrocytes, we ablated microglia starting at the peak of cell death. We used the viability dye acridine orange and monitored apoptotic and lytic cell morphologies after microglial ablation and found that microglia preferentially phagocytose lytic carcasses. In culture, microglia exposed to lytic carcasses partially recapitulated the CAM state, suggesting that phagocytosis contributes to this distinct microglial state during cuprizone demyelination.
Project description:We examined the role of TREM2 on microglia responses to demyelination Microglia were FACS-purified from WT or Trem2-/- mice fed with 0.2% cuprizone diet.
Project description:Mouse cuprizone (CPZ ) model of experimental de- and remyelination was applied to mimic demyelination pathology of multiple sclerosis. In order to identify differentially expressed microRNAs involved in de- and remyelination, the affected areas of corpus callosum were isolated from mice exposed to CPZ and conducted an Agilent microarray analysis. To induce demyelination, CPZ was administrated for four weeks. Spontaneous remyelination occurs as mice returned to the regular diet after four weeks feeding with CPZ (DEM_4w). Remyelination was examined at two time points: acute remyelination induced by four weeks CPZ feeding followed by two days of regular diet (two days remyelination: REM_2d), and full remyelination induced by four weeks CPZ feeding followed by two weeks of regular diet (two weeks remyelination: REM_2w). Control mice (C) were kept on a normal diet. The following groups representing de- and remyelinisation pathology in corpus callosum of CPZ-treated mice were compared: Demyelination: 4weeks CPZ: DEM_4w; Acute remyelination: 4 weeks CPZ +2 days UNTREATED: REM_2d; Full remyelination: 4 weeks CPZ +2 weeks UNTREATED: REM_2w; and UNTREATED control (C). The experiments were performed using 2-4 animals per groups.
Project description:Demyelination is a hallmark of multiple sclerosis, leukoencephalopathies, cerebral vasculopathies and several neurodegenerative diseases. The cuprizone mouse model is widely used to simulate demyelination occurring in these diseases. Here, we present a high-resolution snRNA-seq analysis of gene expression changes across all brain cells in this model. We define signatures of prototypic responses to demyelination and remyelination for each cell type, including anti-stress, anti-oxidant-, metabolic-, hypoxia-, IFN-, and IL-33-driven responses, and validate them at the protein level and in IL-33R-deficient mice. We identify related transcription regulators underpinning these pathways, including STAT3, NF-κB, OLIG1 and MAFB. Furthermore, snRNA- seq data provide novel insights into how various brain cell types connect and interact, defining complex circuitries previously unknown to impact demyelination and remyelination. As an explicative example, perturbation of microglia caused by TREM2 deficiency impacts the oligodendrocyte responses to demyelination. Altogether, this study provides a rich resource for future studies investigating mechanisms underlying demyelination and remyelination.
Project description:Demyelination is a hallmark of multiple sclerosis, leukoencephalopathies, cerebral vasculopathies and several neurodegenerative diseases. The cuprizone mouse model is widely used to simulate demyelination occurring in these diseases. Here, we present a high-resolution snRNA-seq analysis of gene expression changes across all brain cells in this model. We define signatures of prototypic responses to demyelination and remyelination for each cell type, including anti-stress, anti-oxidant-, metabolic-, hypoxia-, IFN-, and IL-33-driven responses, and validate them at the protein level and in IL-33R-deficient mice. We identify related transcription regulators underpinning these pathways, including STAT3, NF-κB, OLIG1 and MAFB. Furthermore, snRNA- seq data provide novel insights into how various brain cell types connect and interact, defining complex circuitries previously unknown to impact demyelination and remyelination. As an explicative example, perturbation of microglia caused by TREM2 deficiency impacts the oligodendrocyte responses to demyelination. Altogether, this study provides a rich resource for future studies investigating mechanisms underlying demyelination and remyelination.