Project description:We inflicted TBI to chemokine-deficient mouse lines in order to establish involvement of various signalling pathways that may be addressed therapeutically. Interacting chemokine pathways in brain regulate distinct inflammatory cells. Activated microglia are separate from invading phagocytes and dendritic cells. Findings show potential targets to interfere with specific inflammatory responses after brain injury. TBI was carried out in Ccl3-/- and Ccr2-/- mice, total RNA prepared from injured cerebral neocortex after three days. RNA samples were from uninjured Ccl3-/- and Ccr2-/- mice as reference for hybridization on Affymetrix microarrays.
Project description:We inflicted TBI to chemokine-deficient mouse lines in order to establish involvement of various signalling pathways that may be addressed therapeutically. Interacting chemokine pathways in brain regulate distinct inflammatory cells. Activated microglia are separate from invading phagocytes and dendritic cells. Findings show potential targets to interfere with specific inflammatory responses after brain injury.
Project description:Brain myeloid cells, including infiltrating monocyte-derived macrophages (MDMs) and resident microglia play critical roles in regulating debris clearance following ischemic brain injury, shaping neuroinflammation evolution and neurological outcome, yet the underlying mechanism remains elusive. In this study, using single-cell RNA sequencing and fate mapping, we identified serotonin receptor Htr2b+ MDMs as a pivotal subgroup involved in resolving neuroinflammation within the ischemic penumbra. In addition, we find significant accumulation of Htr2b+ MDMs with enhanced phagocytosis and inflammation-resolving gene signatures in the peri-infarct region. Mechanistically, Htr2b activation promotes nuclear translocation of Tfe3, a key lysosomal regulator, enhancing lysosomal biogenesis and supporting sustained phagocytic activity. Myeloid-specific Htr2b ablation impairs debris clearance, exacerbates neuroinflammation and ischemic injury, while pharmacological Htr2b agonism or Tfe3 activation restores the lysosomal competence of brain MDMs and improves post-stroke neurological outcome. In conclusion, we demonstrate a novel Htr2b+ MDM subset that integrates serotonin signaling to license their intrinsic phagocytosis function, alleviating ischemic brain injury.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:Epigenetic modifications, such as cytosine methylation and histone modification, have been shown involved in the pathology of ischemic brain injury. Recent works have implicated 5-hydroxymethylcytosine (5hmC), a DNA base derived from 5-methylcytosine (5mC) through the oxidation by Ten-Eleven Translocation (TET) enzymes, in DNA methylation-related plasticity. In this study we show that 5hmC abundance could be induced to increase by ischemia injury. Genome-wide profiling of 5hmC identified differentially hydroxymethylated regions (DhMRs) associated with ischemic injury and DhMRs were found enriched among the genes involved in cell junction, neuronal morphogenesis and neurodevelopment. These data together suggest that 5hmC modification could serve as a potential therapeutic target for the treatment of ischemic stroke. To determine the genome-wide 5hmC distribution in both ischemic injury (I/R) and control mice (C57BL/6), we employed a previously established chemical labeling and affinity purification method, coupled with high-throughput sequencing (Song et al, Nature Biotechnology, 2011). The ischemic or matched control brain tissues from three pairs of ischemic mice and control mice were used for the analyses.
