Project description:Emerging evidence suggests that the meningeal compartment plays instrumental roles in various neurological disorders and can modulate neurodevelopment and behavior. While this has sparked great interest in the meninges, we still lack fundamental knowledge about meningeal biology. Here, we utilized high-throughput RNA sequencing (RNA-seq) techniques to investigate the transcriptional response of the meninges to traumatic brain injury (TBI) and aging in the sub-acute and chronic time frames. Using single-cell RNA sequencing (scRNA-seq), we first explored how mild TBI affects the cellular and transcriptional landscape in the meninges in young mice at one week post-injury. Then, using bulk RNA sequencing, we assessed the differential long-term outcomes between young and aged mice following a TBI. In our scRNA-seq studies, we found that mild head trauma leads to an activation of type I interferon (IFN) signature genes in meningeal macrophages as well as the mobilization of multiple distinct sub-populations of meningeal macrophages expressing hallmarks of either classically activated or wound healing macrophages. We also revealed that dural fibroblasts in the meningeal compartment are highly responsive to TBI, and pathway analysis identified differential expression of genes linked to various neurodegenerative diseases. For reasons that remain poorly understood, the elderly are especially vulnerable to head trauma, where even mild injuries can lead to rapid cognitive decline and devastating neuropathology. To better understand the differential outcomes between the young and the elderly following brain injury, we performed bulk RNA-seq on young and aged meninges from mice that had received a mild TBI or Sham treatment 1.5 months prior. Notably, we found that aging alone induced massive upregulation of meningeal genes involved in antibody production by B cells and type I IFN signaling. Following injury, the meningeal transcriptome had largely returned to its pre-injury signature in young mice. In stark contrast, aged TBI mice still exhibited massive upregulation of immune-related genes and markedly reduced expression of genes involved in extracellular matrix remodeling and maintenance of cellular junctions. Overall, these findings illustrate the dynamic and complex transcriptional response of the meninges to mild head trauma. Moreover, we also reveal how aging modulates the meningeal response to TBI.
Project description:Emerging evidence suggests that the meningeal compartment plays instrumental roles in various neurological disorders and can modulate neurodevelopment and behavior. While this has sparked great interest in the meninges, we still lack fundamental knowledge about meningeal biology. Here, we utilized high-throughput RNA sequencing (RNA-seq) techniques to investigate the transcriptional response of the meninges to traumatic brain injury (TBI) and aging in the sub-acute and chronic time frames. Using single-cell RNA sequencing (scRNA-seq), we first explored how mild TBI affects the cellular and transcriptional landscape in the meninges in young mice at one week post-injury. Then, using bulk RNA sequencing, we assessed the differential long-term outcomes between young and aged mice following a TBI. In our scRNA-seq studies, we found that mild head trauma leads to an activation of type I interferon (IFN) signature genes in meningeal macrophages as well as the mobilization of multiple distinct sub-populations of meningeal macrophages expressing hallmarks of either classically activated or wound healing macrophages. We also revealed that dural fibroblasts in the meningeal compartment are highly responsive to TBI, and pathway analysis identified differential expression of genes linked to various neurodegenerative diseases. For reasons that remain poorly understood, the elderly are especially vulnerable to head trauma, where even mild injuries can lead to rapid cognitive decline and devastating neuropathology. To better understand the differential outcomes between the young and the elderly following brain injury, we performed bulk RNA-seq on young and aged meninges from mice that had received a mild TBI or Sham treatment 1.5 months prior. Notably, we found that aging alone induced massive upregulation of meningeal genes involved in antibody production by B cells and type I IFN signaling. Following injury, the meningeal transcriptome had largely returned to its pre-injury signature in young mice. In stark contrast, aged TBI mice still exhibited massive upregulation of immune-related genes and markedly reduced expression of genes involved in extracellular matrix remodeling and maintenance of cellular junctions. Overall, these findings illustrate the dynamic and complex transcriptional response of the meninges to mild head trauma. Moreover, we also reveal how aging modulates the meningeal response to TBI.
Project description:The goal of this study is to use bulk RNA-sequencing of the right brain hemisphere to observe the effects of TBI in the context of pre-existing meningeal lymphatic dysfunction in mice. We find that pre-existing meningeal lymphatic dysfunction potentiates the inflammatory response to TBI, suggesting an important role for the meningeal lymphatics in injury site drainage and proper recovery.
Project description:Time dependent-profiles in the gene expression level following lateral moderate fluid percussion injury in the rat brain We used microarray to elucidate relationship between the alteration of gene expression levels and the progression of brain damages following traumatic brain injury. To examine the levels of gene expression in the early phase of traumatic brain injury, we analyzed the gene expression at 3, 6, 12, and 48 h after trauma using the lateral moderate fluid percussion TBI model. The ratios of the gene expression level were compared between chips corresponding to the 3, 6 and 12 h fluid percussion groups and the sham group chips. On the other hand, the rations of gene expression level after 48 h FPI were compared with 48 h sham chip, because the gene expression levels of 48 h sham chip were distinct from sham group chips (3, 6 and 12 h) in the cluster and principal components analyses.
Project description: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.