Functional analysis and transcriptome profile of meninges and skin fibroblasts from human aged donors
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ABSTRACT: The central nervous system (CNS) is surrounded by three membranes called meninges. Specialized fibroblasts, originating from the mesoderm and neural crest, primarily populate the meninges and serve as a binding agent. Our goal was to compare fibroblasts from meninges and skin obtained from the same human-aged donors, exploring their molecular and cellular characteristics related to CNS functions. We isolated meningeal fibroblasts (MFs) and skin fibroblasts (SFs) from brain donors. A functional analysis was performed measuring cell appearance, metabolic activity, and cellular orientation. We examined fibronectin, serpin H1, β-III-tubulin, and nestin through qPCR and immunofluorescence. A whole transcriptome analysis was also performed to characterize the gene expression of MFs and SFs. MFs appeared more rapidly post-tissue processing, while SFs have an elevated cellular metabolism and a well-defined cellular orientation. The four markers were mostly similar between the MFs and SFs, except for nestin, more expressed in MFs. Transcriptome analysis reveals significant differences, particularly in cyclic adenosine monophosphate (cAMP) metabolism and response to forskolin, both of which are upregulated in MFs. This study highlights MFs' unique characteristics, such as the timing of appearance, metabolic activity, and gene expression patterns, particularly in cAMP metabolism and response to forskolin. These findings contribute to a deeper understanding of non-neuronal cells' involvement in CNS activities and potentially open avenues for therapeutic exploration.
Project description:The meninges are a multilayered structure composed of fibroblasts, blood and lymphatic vessels, and immune cells. Meningeal fibroblasts secrete a variety of factors that control CNS development, yet strikingly little is known about their heterogeneity or development. Using single cell sequencing, we report distinct transcriptional signatures for fibroblasts in the embryonic dura, arachnoid and pial. We define new markers for meningeal layers and show conservation in human meninges. We find that embryonic meningeal fibroblasts are transcriptionally distinct between brain regions and identify a regionally localized pial sub-population marked by expression of µ-Crystallin. Developmental analysis reveals a progressive, ventral to dorsal maturation of telencephalic meninges. Our studies present an unprecedented view of meningeal fibroblasts, providing a molecular profile of embryonic meningeal fibroblasts by layer that yield insights into mechanisms of meninges development and function.
Project description:OBJECTIVE: MicroRNAs (miRNAs, miRs), a class of small non-coding RNA molecules, are posttranscriptional regulators involved in a plethora of cellular functions and have been proposed as potential therapeutic targets in various diseases, including rheumatoid arthritis (RA). In this study, we sought to discover novel miR associations in synovial fibroblasts (SFs), a key cell type mediating RA pathogenesis, by performing miR expression profiling on cells isolated from the human TNF transgenic mouse model (TghuTNF or Tg197). METHODS: miR expression in SFs isolated from 8-week-old, fully diseased TghuTNF and WT littermate control mice were determined by deep sequencing of small RNAs and the arthritic profile was established by pairwise comparisons of the two groups. qRT-PCR analysis was utilised for profile validation purposes and miR quantitation in patient SFs. Dysregulated miR target genes and pathways were predicted via bioinformatic algorithms. Synovial Fibroblasts isolated from TghuTNF mice (2 x biological replicates) and control WT littermate mice (2 x biological replicates)
Project description:The meninges contain adaptive immune cells that provide immunosurveillance of the CNS. These cells are thought to derive from the systemic circulation. Through single cell analyses, confocal 35 imaging, bone marrow chimeras and parabiosis experiments, we show that meningeal B cells derive locally from the calvaria, which harbors a bone marrow niche for hematopoiesis. B cells reach the meninges from the calvaria through specialized vascular connections. This calvaria- meningeal path of B cell development may provide the CNS with a constant supply of B cells educated by CNS antigens. Conversely, we show that a subset of antigen-experienced B cells that 40 populate the meninges in aging mice are blood-borne. These results identify a private source for meningeal B cells which may help maintain immune privilege within the CNS.
Project description:The meninges contain adaptive immune cells that provide immunosurveillance of the CNS. These cells are thought to derive from the systemic circulation. Through single cell analyses, confocal 35 imaging, bone marrow chimeras and parabiosis experiments, we show that meningeal B cells derive locally from the calvaria, which harbors a bone marrow niche for hematopoiesis. B cells reach the meninges from the calvaria through specialized vascular connections. This calvaria- meningeal path of B cell development may provide the CNS with a constant supply of B cells educated by CNS antigens. Conversely, we show that a subset of antigen-experienced B cells that 40 populate the meninges in aging mice are blood-borne. These results identify a private source for meningeal B cells which may help maintain immune privilege within the CNS.
Project description:We applied quantitative mass spectrometry (MS)-based proteomics to investigate the phosphoproteome of hTNF-stimulated and Amisulpride-treated synovial fibroblasts (SFs), as part of a study aiming to find new potent orally-administered therapeutics to reverse the pathogenic expression signature of arthritogenic SFs. Phosphoproteomics analysis were done by DIA-based phosphoproteomic profiling of synovial fibroblasts. Samples consisted of hTNF-induced WT SFs. Three different time points (5’, 15’, 30’) of hTNF induction were used and compared to cells pretreated with Amisulpride for 1h before being stimulated at similar time points with hTNF (5’, 15’, 30’).
Project description:Aim: Synovial fibroblasts (SFs) undergo a rewiring of their DNA methylation landscape that is associated with their development of an aggressive pathogenic phenotype during Rheumatoid Arthritis (RA), both in humans and in CIA, a mouse model of this chronic inflammatory disease. The helminth-derived immunomodulator, ES-62 acts to prevent joint destruction in CIA by suppressing pathogenic SF responses. We therefore investigated whether ES-62 suppressed the changes in DNA methylation observed in SFs from CIA, relative to those from healthy, mice. Methods: The DNA methylation status of SFs from naïve (no induction of CIA), CIA and ES-62-treated mice undergoing CIA (CIA_ES-62) was compared by Reduced Representation Bilsulphite Sequencing (RRBS) analysis performed by the Active Motif service. Results: Synovial fibroblasts from naive, CIA and CIA_ES-62 mice exhibit differential genomic methylation profiles. Conclusion: ES-62 protection against joint protection in CIA is not associated with prevention of the changes in DNA methylation occurring during rewiring of naive SFs to aggressively pathogenic CIA SFs but rather, reflects generation of a distinct ES-62 phenotype of SF genomic methylation.
Project description:2nd generation sequencing was used to compare expression profiles of MBP-specific T cells retrieved from blood, CSF, spinal cord meninges and parenchyma. The overall expression profiles were found to be very similar.However, genes regulated during T cell activation were found to be upregulated in T cells from spinal cord meninges and parenchyma compared to blood and CSF. 2nd generation sequencing of MBP-specific T cells retrieved from blood and CNS compartments during experimental autoimmune encephalomyelitis
Project description:OBJECTIVE: MicroRNAs (miRNAs, miRs), a class of small non-coding RNA molecules, are posttranscriptional regulators involved in a plethora of cellular functions and have been proposed as potential therapeutic targets in various diseases, including rheumatoid arthritis (RA). In this study, we sought to discover novel miR associations in synovial fibroblasts (SFs), a key cell type mediating RA pathogenesis, by performing miR expression profiling on cells isolated from the human TNF transgenic mouse model (TghuTNF or Tg197). METHODS: miR expression in SFs isolated from 8-week-old, fully diseased TghuTNF and WT littermate control mice were determined by deep sequencing of small RNAs and the arthritic profile was established by pairwise comparisons of the two groups. qRT-PCR analysis was utilised for profile validation purposes and miR quantitation in patient SFs. Dysregulated miR target genes and pathways were predicted via bioinformatic algorithms.
Project description:Tertiary lymphoid structures (TLS) are organized aggregates of B and T cells formed ectopically during different life periods in response to inflammation, infection, or cancer. Here, we describe formation of structures reminiscence of TLS in the spinal cord meninges under several central nervous system (CNS) pathologies. Following acute spinal cord injury, B and T lymphocytes locally aggregate within the meninges to form TLS, which continue to accumulate during the late phase of repair, with a negative impact on subsequent pathological conditions, such as experimental autoimmune encephalomyelitis. Using a chronic model of spinal cord pathology, the mSOD1 mouse model of amyotrophic lateral sclerosis, we further showed by single cell RNA-sequencing that a meningeal lymphocyte niche forms, with a unique organization and activation state, including accumulation of pre-B cells in the spinal cord meninges. Such a response was not found in the CNS-draining cervical lymph nodes. The present findings suggest that a unique immune response develops in the meninges during various neurological pathologies in the CNS, a reflection of its immune privileged nature.
Project description:In this work we report that early developing B cells present in the meninges of mice at all ages. Single cell RNA-sequencing (scRNA-seq) analysis revealed a consecutive trajectory of meningeal developing B cells in mice and non-human primates (NHPs). Parabiosis together with lineage tracing of hematopoietic stem cells (HSCs) showed that meningeal developing B cells are continuously replenished from the HSC-derived progenitors via a circulation-independent route. Importantly, autoreactive immature B cells which recognize myelin oligodendrocyte glycoprotein (MOG), a central nervous system (CNS)-specific antigen, are eliminated from the meninges but not BM. Furthermore, genetic deletion of MOG tolerated the development/presence/residence of self-reactive B cells in the meninges. Thus, we propose that meninges function as a unique reservoir for B cell development, allowing in situ negative selection of CNS-antigen-autoreactive B cell clones to ensure a local non-self-reactive immune repertoire.