Project description:The maintenance of water homeostasis under pathological conditions is mediated by the aquaporin-4 (AQP4) channel in astrocytes. To clarify the transcriptional regulation for AQP4 under conditions of astrocytic swelling, we examined the role of nuclear factor of activated T cells 5 (NFAT5). We evaluated NFAT5 expression patterns after the induction of brain edema and following excitotoxic neuronal death by kainic acid injection. In injured hippocampi, NFAT5 expression increased in astrocytes from 12 h to 3 days post-injection. AQP4 was redistributed from perivascular to whole-cell processes in astrocytes. NFAT5 and AQP4 expression increased under astrocytic swelling induced by ammonia treatment, and NFAT5-targeted silencing significantly reduced AQP4 expression. The promoter region required for NFAT5 transcriptional activation was located between -49 and -38 bp of rat AQP4. The amount of NFAT5 bound to the promoter of AQP4 was increased in response to ammonia. Our data demonstrate that NFAT5 is necessary for the transcriptional regulation of AQP4 expression and for local astrocyte swelling with accompanying restriction of the neuropil extracellular space in vivo.
Project description:We report MAFG recruitment to ARE elements in astrocytes during EAE compared to naïve mice Multiple sclerosis (MS) is an autoimmune neurologic disease leading to demyelination and neurologic dysfunction controlled by both genetic and environmental factors. In addition to CNS-infiltrating immune cells, CNS-resident cells, such as astrocytes, are thought to play an important role in MS pathogenesis. However, a comprehensive understanding of the extent to which gene expression is disrupted in astrocytes is not known. Here, we implement single-cell RNA sequencing, in vivo genetic perturbations, cell-specific RNA profiling by Ribotag, as well as single-cell RNA sequencing of human MS patient samples to identify a transcriptional regulatory network in astrocytes that controls the pathogenesis of EAE and potentially, MS. We defined an astrocyte subpopulation characterized by expression of the small Maf protein, MAFG, which represses NRF2-driven antioxidant mechanisms and promotes EAE pathogenesis. Mechanistically, MAFG suppresses NRF2-dependent antioxidant genetic programs by cooperating with its cofactor, MAT2a, to promote DNA methylation in the context of CNS inflammation, which in turn increases pathogenic signaling processes in astrocytes. MAFG/MAT2a astrocytes are controlled by GM-CSF signaling, which drives EAE pathogenesis and MAFG expression. MAFG is activated in astrocytes derived from MS patients, which are characterized by DNA methylation programs, pro-inflammatory signaling processes including GM-CSF signaling, and repressed NRF2 activation. Together, these data create a transcriptional and epigenetic framework to analyze CNS inflammation in MS and may provide new therapeutic targets.
Project description:To determine the role of RIPK1 kinase signaling in microglia and astrocytes during EAE (mouse model of MS), we extracted spinal cords of naive, EAE-vehicle and EAE mice treated with RIPK1 kinase inhibitor (GSK’547) for transcript profiling using RNAseq. We identify various genes that are differentially expressed in EAE disease compared to naive mice, and a subset of these are modulated in a RIPK1 kinase-dependent manner in both astrocytes and microglia. The top RIPK1 kinase-dependent gene pathways include oxidative phosphorylation and mitochondrial dysfunction in microglia and EIF2 signaling and cholesterol biosynthesis in astrocytes. This study demonstractes critical and distinct roles for RIPK1 kinase signaling in both microglia and astrocytes during EAE
Project description:We reported that knockdown of sphingolipid metabolism in astrocytes has impact to interfere EAE pathological progressing in NOD mice
Project description:The purpose of this study is to compare transcriptional profiles of WT and STAT4-deficient Th17 cultured cells from mice with experimental autoimmune encephalomyelitis (EAE) using RNA sequencing. WT and STAT4 deficient splenocytes from EAE immunized mice were cultured with MOG peptide under Th17 conditions for three days, and then total RNA was extracted from CD4 T cells for sequencing. Differential gene expression was determined using the DESeq2 algorithm. These data reveal a previously unrecognized role for STAT4 in Th17 gene expression and function.
