Project description:Microglia are macrophages-like cells in the central nervous system (CNS) harboring important roles such as synaptic organization, phagocytosis of debris and apoptotic cells, and repairing damaged tissue. Microglial function is tightly controlled, but under certain pathological conditions, activated microglia can induce excess inflammation which injure live cells in the CNS. Therefore, suppression of microglia is a fundamental strategy to treat CNS disorders. We have previously shown that the antiepileptic drug levetiracetam (LEV) inhibits microglia activation, but mechanism remains unclear. The purpose of this study is to identify a target of LEV to suppress microglial activity.
Project description:Expression profiling by high throughput sequencing Microglial cells have a double life as the immune cells of the brain in times of stress but have also specific physiological functions in homeostatic conditions. In pathological contexts, microglia undergo a phenotypic switch called “reaction” ’that promotes the initiation and the propagation of neuro-inflammation. Reaction is complex, molecularly heterogeneous and still poorly characterized, leading to the concept that microglial reactivity might be too diverse to be molecularly defined. However, it remains unknown whether reactive microglia from different pathological contexts share a common molecular signature. Using improved flow cytometry and RNAseq approaches we studied, with higher statistical power, the remodeling of microglia transcriptome in a mouse model of sepsis. Through bioinformatic comparison of our results with published datasets, we defined the microglial reactome as a set of genes discriminating reactive from homeostatic microglia. Ultimately, we identified a subset of 86 genes deregulated in both acute and neurodegenerative conditions. Our data provide a new comprehensive resource that includes functional analysis and specific molecular makers of microglial reaction which represent new tools for its unambiguous characterization.
Project description:Adenosine triggers early astrocyte reactivity that provokes microglial reaction and drives the pathogenesis of sepsis-associated encephalopathy
Project description:Molecular pathways mediating systemic inflammation entering the brain parenchyma to induce sepsis-associated encephalopathy (SAE) remain elusive. Here, we report that in mice during the first 6 hours of peripheral lipopolysaccharide (LPS)-evoked systemic inflammation (6 hpi), the plasma level of adenosine quickly increased and enhanced the tone of central extracellular adenosine which then provoked neuroinflammation by triggering early astrocyte reactivity. Specific ablation of astrocytic A1 adenosine receptors (A1ARs) prevented this early reactivity and reduced the levels of inflammatory factors (e.g., CCL2, CCL5, and CXCL1) in astrocytes, thereby alleviating microglial reaction, ameliorating blood-brain barrier disruption, peripheral immune cell infiltration, neuronal dysfunction, and depression-like behaviour in the mice. Chemogenetic stimulation of Gi signaling in A1AR-deficent astrocytes at 2 and 4 hpi of LPS injection could restore neuroinflammation and depression-like behaviour, highlighting astrocytes rather than microglia as early drivers of neuroinflammation. Our results identify early astrocyte reactivity towards peripheral and central levels of adenosine as a novel pathway driving SAE and highlight the potential of targeting A1ARs for therapeutic intervention.
Project description:Siponimod (Mayzent®), a sphingosine 1-phosphate receptor (S1PR) modulator which prevents lymphocyte egress from lymphoid tissues, is approved for the treatment of relapsing-remitting- and active secondary progressive multiple sclerosis. It can cross the blood-brain-barrier (BBB) and selectively binds to S1PR1 and S1PR5 expressed by several cell populations of the central nervous system (CNS) including microglia. To investigate wether Siponimod modulates the genetic signature of inflammed microglia, we performed a transcriptome analyses of primary rat microglial cells stimulated with LPS and With or Without Siponimod.
Project description:We conducted small RNA sequencing and bioinformatics analysis of GCH1-KD BV2 microglial cells treated with adenovirus. Their RNA was extracted and analyzed, and the results were verified by quantitative real-time polymerase chain reaction (qRT-PCR). This study explored the miRNAs and mRNAs regulated by GCH1 and revealed a possible mechanism of GCH1 in microglial activation.
Project description:Here, we report the characterization and the comparison of the transcriptomes of BV-2 murine microglial mutant cell lines (CRISPR/Cas9-edited mutations in peroxisomal genes) by RNA-sequencing. Microglia is suspected to play a major role in the neurodegenerative processes observed in peroxisomal leukodystrophies. From CRISPR/Cas9-edited BV-2 microglial cell lines, we aimed at exploring the transcriptomic consequences of a defect of peroxisomal beta-oxidation.
Project description:We conducted high-throughput sequencing and bioinformatics analysis of GCH1-KD BV2 microglial cells treated with adenovirus. Their RNA was extracted and analyzed, and the results were verified by quantitative real-time polymerase chain reaction (PCR). This study explored the lncRNAs, miRNAs, circRNAs and mRNAs regulated by GCH1 and revealed a possible mechanism of GCH1 in microglia activation.