Project description:Injury to the adult brain induces activation of resident astrocytes, which serves as a compensatory response modulating tissue damage and recovery. However, the mechanism governing astrocyte activation and the role of reactive astrocytes remain largely unknown. Here we show that SOX2, a transcription factor critical for stem cells and brain development, is also required for injury-induced activation of adult cortical astrocytes. Genome-wide ChIP-seq analysis reveals that SOX2 binds to regulatory regions of genes associated with signaling pathways controlling reactive gliosis, such as Socs3, Nr2e1, Notch1, and Akt2. Inducible deletion of Sox2 in adult astrocytes greatly diminishes their response to traumatic injury and, most unexpectedly, restricts injury-induced cortical loss. Together, these results uncover an essential role of SOX2 in terminally differentiated cells and implicate that SOX2-dependent reactive astrocytes may be targeted for regeneration after traumatic brain injury.
Project description:The interaction between neurogenesis and angiogenesis after traumatic brain injury is a complex and dynamic process. To resolve this, we chose the zebrafish model organism for studying brain wound healing via systems biology approach. Transcriptome microarray data and histological analysis of injured fish were sampled at different time points during recovery process. Time-course microarray data following wound healing of zebrafish were obtained. From this set of data, we constructed two intracellular protein–protein interaction (PPI) networks for the traumatic brain injury healing mechanism.
Project description:Single-nuclei Assay for Transposase-Accessible Chromatin with sequencing (snATACseq) was applied to examine chromatin landscape changes and transcriptional regulator (TR) DNA motif accessibility in reactive astrocytes following traumatic spinal cord injury (SCI). Astrocyte nuclei were isolated from the spinal cord of wild type mice and mice with astrocyte-specific conditional gene deletion (cKO) of test-case TRs, SMARCA4 (Smarca4-astro-cKO) or STAT3 knockout (Stat3-astro-cKO). Comparison of differential chromatin accessibility revealed substantial remodeling during astrocyte reactivity, with more chromatin opening than closing. Marked alterations in access to SCI reactivity-associated TR motifs were also detected.
Project description:The glial environment determines the outcome of neurological disease progression, yet much of our knowledge still relies on preclinical animal studies, especially regarding astrocyte heterogeneity. In murine models of traumatic brain injury, beneficial functions of proliferating reactive astrocytes on disease outcome have been unraveled, but little is known if and when they are present in human brain pathology. Here, we examined a broad spectrum of pathologies with and without intracerebral hemorrhage and found a striking correlation between lesions involving blood-brain barrier rupture and astrocyte proliferation that was further corroborated in an assay probing for neural stem cell potential. Most importantly, proteomic analysis unraveled a crucial signaling pathway regulating this astrocyte plasticity with GALECTIN3 as a novel marker for proliferating astrocytes and the GALECTIN3-binding protein LGALS3BP as a functional hub mediating astrocyte proliferation and neurosphere formation. Taken together, this work identifies a therapeutically relevant astrocyte response and their molecular regulators in different pathologies affecting the human cerebral cortex.
Project description:Explore DNA methylation in traumatic brain injury model of epilepsy and its relationship to gene expression. Examination of methylation changes in stimulated rats compared to sham operated animals in traumatic brain injury model of epilepsy.
Project description:Explore DNA methylation in traumatic brain injury model of epilepsy and its relationship to gene expression. Examination of expression changes in stimulated rats compared to sham operated animals in traumatic brain injury model of epilepsy.
Project description:The interaction between neurogenesis and angiogenesis after traumatic brain injury is a complex and dynamic process. To resolve this, we chose the zebrafish model organism for studying brain wound healing via systems biology approach. Transcriptome microarray data and histological analysis of injured fish were sampled at different time points during recovery process. Time-course microarray data following wound healing of zebrafish were obtained. From this set of data, we constructed two intracellular proteinM-bM-^@M-^Sprotein interaction (PPI) networks for the traumatic brain injury healing mechanism. Each fish in each group was injured by a 1.5 mm, 27G needle tip from day 0 to 28, respectively. These injured fish were collected at 0, 0.25, 1, 3, 6, 10, 15, 21, 28 dpi (day post injury). 0.625M-NM-<g of Cy3 cRNA for C. albicans array and 1.65 M-NM-<g of Cy3 cRNA for zebrafish array was fragmented to an average size of about 50-100 nucleotides by incubation with fragmentation buffer at 60M-BM-0C for 30 minutes. Each time point contain two biological repeats.
Project description:Traumatic Brain injury-induced disturbances in mitochondrial fission-and-fusion dynamics have been linked to the onset and propagation of neuroinflammation and neurodegeneration. However, cell-type-specific contributions and crosstalk between neurons, microglia, and astrocytes in mitochondria-driven neurodegeneration after brain injury remain undefined. We developed a human three-dimensional in vitro triculture tissue model of a contusion injury composed of neurons, microglia, and astrocytes and examined the contributions of mitochondrial dysregulation to neuroinflammation and progression of injury-induced neurodegeneration. Pharmacological studies presented here suggest that fragmented mitochondria released by microglia are a key contributor to secondary neuronal damage progression after contusion injury, a pathway that requires astrocyte-microglia crosstalk. Controlling mitochondrial dysfunction thus offers an exciting option for developing therapies for TBI patients.
Project description:Background: Traumatic brain injury is a medical event of global concern, and a growing body of research suggests that circular RNA can play very important roles in traumatic brain injury. To explore the functions of more novel and valuable circular RNA in traumatic brain injury response, a moderate traumatic brain injury in rat was established and a comprehensive analysis of circular RNA expression profiles in rat cerebral cortex was done. Results: As a result, 301 up-regulated and 284 down-regulated circular RNAs were obtained in moderate traumatic brain injury rats, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed based on the circular RNA’s host genes, and a circRNA-miRNA interaction network based on differentially expressed circular RNAs was constructed. Also, four circular RNAs were validated by RT-qPCR and sanger sequencing. Conclusion: This study showed that differentially expressed circular RNAs existed between rat cerebral cortex after moderate traumatic brain injury and control. And this will provide valuable information for circular RNA research in the field of traumatic brain injury.