The meningeal space is occupied by a diverse repertoire of innate and adaptive immune cells. CNS injury elicits a rapid immune response that affects neuronal survival and recovery, but the role of meningeal inflammation in CNS injury remains poorly understood. Here we describe group 2 innate lymphoid cells (ILC2s) as a novel cell type resident in the healthy meninges that is activated following CNS injury. ILC2s are present throughout the naïve mouse meninges, though are concentrated around the dural sinuses, and have a unique transcriptional profile relative to lung ILC2s. After spinal cord injury, meningeal ILC2s are activated in an IL-33 dependent manner, producing type 2 cytokines. Using RNAseq, we characterized the gene programs that underlie the ILC2 activation state. Finally, addition of wild type lung-derived ILC2s into the meningeal space of IL-33R-/- animals improves recovery following spinal cord injury. These data characterize ILC2s as a novel meningeal cell type that responds to and functionally affects outcome after spinal cord injury, and could lead to new therapeutic insights for CNS injury or other neuroinflammatory conditions. Overall design: ILC2s were isolated from 10 week C57/Bl6 mice with and without spinal cord injury (1 day post injury). 5 mice were pooled per group, with meninges dissected, digested, and FACs sorted (CD45+/DAPI-/Lin–/St2+/Thy1+) directly into RNA lysis buffer.
Characterization of meningeal type 2 innate lymphocytes and their response to CNS injury.
Age, Specimen part, Cell line, Subject
View SamplesPeripherally derived macrophages infiltrate the brain after bone marrow transplantation and during central nervous system (CNS) inflammation. It was initially suggested that these engrafting cells were newly derived microglia and that irradiation was essential for engraftment to occur. However, it remains unclear whether brain-engrafting macrophages (beMfs) acquire a unique phenotype in the brain, whether long-term engraftment may occur without irradiation, and whether brain function is affected by the engrafted cells. In this study, we demonstrate that chronic, partial microglia depletion is sufficient for beMfs to populate the niche and that the presence of beMfs does not alter behavior. Furthermore, beMfs maintain a unique functional and transcriptional identity as compared with microglia. Overall, this study establishes beMfs as a unique CNS cell type and demonstrates that therapeutic engraftment of beMfs may be possible with irradiation-free conditioning regimens. Overall design: Microglia were isolated from the brains of adult male c57BL/6 mice given bone marrow tranplants (BMT) with or without head shield. All mice received PLX5622 for 2 weeks, then placed and normal chow to recoever. Some mice were then challenged with LPS. Cells were isolated by MACS using CD11b magnetic beads.
Peripherally derived macrophages can engraft the brain independent of irradiation and maintain an identity distinct from microglia.
Age, Specimen part, Cell line, Treatment, Subject
View SamplesPeripherally derived macrophages infiltrate the brain after bone marrow transplantation and during central nervous system (CNS) inflammation. It was initially suggested that these engrafting cells were newly derived microglia and that irradiation was essential for engraftment to occur. However, it remains unclear whether brain-engrafting macrophages (beMfs) acquire a unique phenotype in the brain, whether long-term engraftment may occur without irradiation, and whether brain function is affected by the engrafted cells. In this study, we demonstrate that chronic, partial microglia depletion is sufficient for beMfs to populate the niche and that the presence of beMfs does not alter behavior. Furthermore, beMfs maintain a unique functional and transcriptional identity as compared with microglia. Overall, this study establishes beMfs as a unique CNS cell type and demonstrates that therapeutic engraftment of beMfs may be possible with irradiation-free conditioning regimens. Overall design: Mice were given 1000rad whole body irradiation, followed by bone marrow transplant with UBC-GFP bone marrow at 8 weeks of age. Engraftment was allowed to occur for 8 months, then engrafting macrophages and microglia were isolated from whole brains for RNA-Seq.
Peripherally derived macrophages can engraft the brain independent of irradiation and maintain an identity distinct from microglia.
Age, Specimen part, Cell line, Subject
View SamplesMutations in methyl-CpG-binding protein 2 (MeCP2), a major epigenetic regulator, are the predominant cause of Rett syndrome, an X-linked neurodevelopmental disorder. We previously found that Mecp2-null microglia are functionally impaired, and that engraftment of wild-type monocytes into the brain of Mecp2-deficient mice attenuates pathology. In this study we show that Mecp2 is expressed in macrophage and monocyte populations throughout the body, and is indispensable for their transcriptional regulation in multiple contexts. We demonstrate that Mecp2-null mice progressively lose or are chronically deficient in several macrophage populations and resident monocytes. Postnatal re-expression of Mecp2 driven by a tamoxifen-inducible CX3CR1 promoter significantly increased the lifespan of otherwise Mecp2-null mice, suggesting that epigenetic regulation of macrophage function by Mecp2 significantly contributes to pathology. RNA-Seq of acutely isolated microglia and peritoneal macrophages (to our knowledge, the first cell-specific RNA-Seq analysis comparing Mecp2-null and wild type cells of any kind) revealed significantly increased transcription of glucocorticoid- and hypoxia-signaling genes in Mecp2-null cells compared to that in their wild-type counterparts, suggesting that Mecp2 functions as a repressor of these pathways. Furthermore, in-vitro and in vivo validation studies demonstrated that the absence of Mecp2 is associated with cell-intrinsic dysfunction of signaling underlying inflammatory activation, suggesting that Mecp2 is important for regulation of specific macrophage gene-expression programs in response to stimuli and stressors. Our findings demonstrate a fundamental role for Mecp2 in the regulation of macrophage functions, which may provide a link to pathologies in Rett syndrome across multiple organs. Overall design: Mecp2-null microglia and resident peritoneal macrophages from 10-12 week old mice were acutely isolated via AutoMACS, total RNA collected, and analyzed via RNA-Seq to compare for transcriptional differences in microglia and macrophages in the absence of Mecp2.
Methyl-CpG Binding Protein 2 Regulates Microglia and Macrophage Gene Expression in Response to Inflammatory Stimuli.
No sample metadata fields
View SamplesAging is a major risk factor for many neurological pathologies, including Alzheimer's disease (AD). However, the mechanisms underlying brain aging and cognitive decline remain elusive. Body tissues are perfused by interstitial fluid (ISF), which is locally reabsorbed via the lymphatic vascular network. In contrast, the parenchyma of the central nervous system (CNS) is devoid of lymphatic vasculature; in the brain, removal of cellular debris and toxic molecules, such as amyloid beta (A?) peptides, is mediated by a combination of transcellular mechanisms of transport across the blood-brain and blood-cerebrospinal fluid (CSF) barriers, phagocytosis and digestion by resident microglia and recruited monocytes/macrophages, and CSF influx and ISF efflux through a paravascular route. The recent characterization of meningeal lymphatic vessels prompted a reassessment of the conventional pathways of CNS waste clearance. The role of this vasculature in brain function, specifically in the context of aging and AD, is still poorly understood. Here we show that meningeal lymphatic vessels play an essential role in maintaining brain homeostasis by draining macromolecules from the CNS (CSF and ISF) into the cervical lymph nodes. Using pharmacological, surgical, and genetic models we show that impairment of meningeal lymphatic function in adult mice slows paravascular influx of CSF macromolecules and efflux of ISF macromolecules, and induces cognitive impairment. Treatment with a lymphangiogenic factor, vascular endothelial growth factor C (VEGF-C), enhances meningeal lymphatic drainage of CSF macromolecules, improving brain perfusion and learning and memory performance in aged mice. Disruption of meningeal lymphatic vessels in transgenic mouse models of AD promotes amyloid deposition in the meninges, which closely correlates with human meningeal pathology, and aggravates overall disease severity. Our findings suggest that meningeal lymphatic dysfunction may be an aggravating factor in AD pathology and in age-associated cognitive decline. Thus, augmentation of meningeal lymphatic function might be a promising therapeutic target for preventing or delaying age-associated neurological diseases. Overall design: Male C57BL/6J mice (2 months-old) were injected (intra-cisterna magna) with Visudyne (verteporfin for injection), or vehicle as control, and submitted to a step of photoconversion, to induce meningeal lymphatic vessel ablation. This procedure was repeated 2 weeks later to ensure prolonged meningeal lymphatic dysfunction. 2 weeks after the last surgical procedure, mice were subjected to the MWM test. 3 days after, whole hippocampus was macrodissected and total RNA was extracted for sequencing.
Functional aspects of meningeal lymphatics in ageing and Alzheimer's disease.
Age, Specimen part, Cell line, Treatment, Subject
View SamplesAging is a major risk factor for many neurological pathologies, including Alzheimer's disease (AD). However, the mechanisms underlying brain aging and cognitive decline remain elusive. Body tissues are perfused by interstitial fluid (ISF), which is locally reabsorbed via the lymphatic vascular network. In contrast, the parenchyma of the central nervous system (CNS) is devoid of lymphatic vasculature; in the brain, removal of cellular debris and toxic molecules, such as amyloid beta (A?) peptides, is mediated by a combination of transcellular mechanisms of transport across the blood-brain and blood-cerebrospinal fluid (CSF) barriers, phagocytosis and digestion by resident microglia and recruited monocytes/macrophages, and CSF influx and ISF efflux through a paravascular route. The recent characterization of meningeal lymphatic vessels prompted a reassessment of the conventional pathways of CNS waste clearance. The role of this vasculature in brain function, specifically in the context of aging and AD, is still poorly understood. Here we show that meningeal lymphatic vessels play an essential role in maintaining brain homeostasis by draining macromolecules from the CNS (CSF and ISF) into the cervical lymph nodes. Using pharmacological, surgical, and genetic models we show that impairment of meningeal lymphatic function in adult mice slows paravascular influx of CSF macromolecules and efflux of ISF macromolecules, and induces cognitive impairment. Treatment with a lymphangiogenic factor, vascular endothelial growth factor C (VEGF-C), enhances meningeal lymphatic drainage of CSF macromolecules, improving brain perfusion and learning and memory performance in aged mice. Disruption of meningeal lymphatic vessels in transgenic mouse models of AD promotes amyloid deposition in the meninges, which closely correlates with human meningeal pathology, and aggravates overall disease severity. Our findings suggest that meningeal lymphatic dysfunction may be an aggravating factor in AD pathology and in age-associated cognitive decline. Thus, augmentation of meningeal lymphatic function might be a promising therapeutic target for preventing or delaying age-associated neurological diseases. Overall design: Male C57BL/6J mice (2 months-old) were injected (intra-cisterna magna) with Visudyne (verteporfin for injection), or vehicle as control, and submitted to a step of photoconversion, to induce meningeal lymphatic vessel ablation. This procedure was repeated 2 weeks later to ensure prolonged meningeal lymphatic dysfunction. 2 weeks after the last surgical procedure, whole hippocampus was macrodissected and total RNA was extracted for sequencing.
Functional aspects of meningeal lymphatics in ageing and Alzheimer's disease.
Age, Specimen part, Cell line, Treatment, Subject
View SamplesAging is a major risk factor for many neurological pathologies, including Alzheimer's disease (AD). However, the mechanisms underlying brain aging and cognitive decline remain elusive. Body tissues are perfused by interstitial fluid (ISF), which is locally reabsorbed via the lymphatic vascular network. In contrast, the parenchyma of the central nervous system (CNS) is devoid of lymphatic vasculature; in the brain, removal of cellular debris and toxic molecules, such as amyloid beta (A?) peptides, is mediated by a combination of transcellular mechanisms of transport across the blood-brain and blood-cerebrospinal fluid (CSF) barriers, phagocytosis and digestion by resident microglia and recruited monocytes/macrophages, and CSF influx and ISF efflux through a paravascular route. The recent characterization of meningeal lymphatic vessels prompted a reassessment of the conventional pathways of CNS waste clearance. The role of this vasculature in brain function, specifically in the context of aging and AD, is still poorly understood. Here we show that meningeal lymphatic vessels play an essential role in maintaining brain homeostasis by draining macromolecules from the CNS (CSF and ISF) into the cervical lymph nodes. Using pharmacological, surgical, and genetic models we show that impairment of meningeal lymphatic function in adult mice slows paravascular influx of CSF macromolecules and efflux of ISF macromolecules, and induces cognitive impairment. Treatment with a lymphangiogenic factor, vascular endothelial growth factor C (VEGF-C), enhances meningeal lymphatic drainage of CSF macromolecules, improving brain perfusion and learning and memory performance in aged mice. Disruption of meningeal lymphatic vessels in transgenic mouse models of AD promotes amyloid deposition in the meninges, which closely correlates with human meningeal pathology, and aggravates overall disease severity. Our findings suggest that meningeal lymphatic dysfunction may be an aggravating factor in AD pathology and in age-associated cognitive decline. Thus, augmentation of meningeal lymphatic function might be a promising therapeutic target for preventing or delaying age-associated neurological diseases. Overall design: Lymphatic endothelial cells (LECs) were isolated from meninges of adult (2-3 months-old) or old (20-24 months-old) male C57BL/6 mice. Cells were sorted by FACS according to the following phenotype: CD45-CD31+PDPN+.
Functional aspects of meningeal lymphatics in ageing and Alzheimer's disease.
Specimen part, Cell line, Subject
View SamplesVisceral leishmaniasis (VL), caused by Leishmania spp protozoan parasites, can provoke overwhelming and protracted epidemics, with high casefatality rates. Despite extensive efforts towards the development of an effective prophylactic vaccine, no promising vaccine is available yet for humans. Multi-epitope peptide based vaccine development is manifesting as the new era of vaccination strategies against VL. Aim of the study was the design of chimeric peptides from immunogenic L. infantum proteins for encapsulation in PLGA nanoparticles (NPs) alone or in combination with MPLA adjuvant, or in PLGA NPs surface modified with an octapeptide mimicking TNF-alpha for DCs targeting, in order to construct a peptide-based nanovaccine. The in vitro evaluation of the above nanoformulations was performed in DCs isolated from HLA-A2.1 transgenic mice. Characterization of DCs transcriptional responses to these vaccine candidates via microarrays could improve our understanding of their mechanisms of action on DCs' functional differentiation and the type of adaptive immunity subsequently induced.
A Poly(Lactic-<i>co</i>-Glycolic) Acid Nanovaccine Based on Chimeric Peptides from Different <i>Leishmania infantum</i> Proteins Induces Dendritic Cells Maturation and Promotes Peptide-Specific IFNγ-Producing CD8<sup>+</sup> T Cells Essential for the Protection against Experimental Visceral Leishmaniasis.
Specimen part
View SamplesVisceral leishmaniasis (VL) caused by Leishmania donovani and L. infantum is a potentially fatal disease. To date there are no registered vaccines for disease prevention despite the fact that several vaccines are in preclinical development. Thus, new strategies are needed to improve vaccine efficacy based on a better understanding of the mechanisms mediating protective immunity and mechanisms of host immune responses subversion by immunopathogenic components of Leishmania. In the present study, determination of the immune mechanisms related to infection or protective immune responses against VL using an experimental nanovaccine as a vaccine model was conducted through microarray analysis.
Transcriptome Analysis Identifies Immune Markers Related to Visceral Leishmaniasis Establishment in the Experimental Model of BALB/c Mice.
No sample metadata fields
View SamplesMaternal obesity is linked with increased adverse outcomes for mother and fetus. However, the metabolic impact of excessive fat accumulation within the altered hormonal context of pregnancy is not well understood. We used a murine model of obesity, the high fat diet-fed C57BL/6J mouse to determine adipose tissue-mediated molecular mechanisms driving metabolic dysfunction throughout pregnancy. Remarkably, obese mice exhibited a normalization of visceral fat accumulation at late-stage pregnancy (-53%, P<0.001 E18.5) to achieve levels comparable in mass (per gram of body weight) to that of non pregnant, control diet fed mice. Moreover, whilst obese pregnant mice showed a marked glucose intolerance and apparent insulin resistance at mid-stage pregnancy (E14.5), glucose homeostasis converged with that of lean pregnant mice at late-stage pregnancy, suggesting an unexpected amelioration of the worsening metabolic dysfunction in obese pregnant mice.
Pregnancy in obese mice protects selectively against visceral adiposity and is associated with increased adipocyte estrogen signalling.
Specimen part
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