Project description:Our brains accommodate a largely folded cerebral cortex that associates to our advanced brain functions. Several theories have been proposed to explain the cortical folding process, reasoning the mechanical forces as neuronal tension in underlying layers, cellular expansion and glial progenitor’s diversity in the OSVZ; but the mechanistic insights and underlying genomics changes causing the appearance of cortical folds is still illusive. Importantly, no studies have attempted to comprehensively characterize the gene regulatory networks underlying cortical folding during development. Here, by using ferret as a model system, we have compared the transcriptomes of germinal layers between sulci and gyri, of different cortical areas and across two developmental stages (E30 & E34), to achieve a comprehensive understanding of the spatio-temporal dynamics of gene expression of cortical progenitors. Furthermore, we have also characterized the epigenetic landscape of germinal layers at E30 and E34, a critical period for their development, to correlate changes in chromatin at promoter and enhancer regions with the observed changes in gene expression. Our preliminary results indicate towards a clear transformational axis of gene regulation between germinal layers. By performing motif analysis of differentially expressed gene (DEGs), we reveal transcription factors which might have a critical role in determining cortical folding. The genes targeted by these factors belong to important pathways implicated in proliferation and neurogenesis. We highlight potential candidates in cortical folding through functional validation studies and acetylation (H3K27ac) levels for these genes correlate with their expression state. Importantly, these are critical for cell adhesion, migration and proliferation processes in-line with previous studies stating that proliferative divisions cause neocortical expansions. Our findings will have strong impact on the clinical interventions for neurological disorders relating to cortical malformation, while at the same time enhancing our understanding of molecular circuitry underlying gyrencephalic brain development and folding.
Project description:Evolution of the mammalian brain encompassed a remarkable increase in size of cerebral cortex, including tangential and radial expansion, but the mechanisms underlying these key parameters are still largely unknown. Here, we identified the novel DNA associated protein TRNP1 as a regulator of cerebral cortical expansion in both these dimensions. Gain and loss of function experiments in the mouse cerebral cortex in vivo demonstrate that high Trnp1 levels promote neural stem cell self-renewal and tangential expansion, while lower levels promote radial expansion resulting in a potent increase in the generation of intermediate progenitors and outer radial glial cells resulting in folding of the otherwise smooth murine cerebral cortex. Remarkably, TRNP1 expression levels exhibit regional differences also in the cerebral cortex of human fetuses anticipating radial or tangential expansion respectively. Thus, the dynamic regulation of TRNP1 is critical to regulate tangential and radial expansion of the cerebral cortex in mammals. We performed gene expression microarray analysis on embryonic mouse cerebral cortex derived from Trnp1 knockdown and control animals.
Project description:Evolution of the mammalian brain encompassed a remarkable increase in size of cerebral cortex, including tangential and radial expansion, but the mechanisms underlying these key parameters are still largely unknown. Here, we identified the novel DNA associated protein TRNP1 as a regulator of cerebral cortical expansion in both these dimensions. Gain and loss of function experiments in the mouse cerebral cortex in vivo demonstrate that high Trnp1 levels promote neural stem cell self-renewal and tangential expansion, while lower levels promote radial expansion resulting in a potent increase in the generation of intermediate progenitors and outer radial glial cells resulting in folding of the otherwise smooth murine cerebral cortex. Remarkably, TRNP1 expression levels exhibit regional differences also in the cerebral cortex of human fetuses anticipating radial or tangential expansion respectively. Thus, the dynamic regulation of TRNP1 is critical to regulate tangential and radial expansion of the cerebral cortex in mammals.
Project description:Differential gene expression of cerebral cortex might be responsible for distinct neurovascular developments between different mouse strains We used Affymetrix microarray to explore the global gene expression patterns of mouse cerebral cortex of different mouse strains at two developmental stages Cerebral cortex from two mouse strains [C57BL/6J(B6) and C3H/J (C3H)] at post-natal day 1 (p1) and post-natal 11 weeks (11 wk) were harvested for microarray experiments
Project description:Differential gene expression of cerebral cortex might be responsible for distinct neurovascular developments between different mouse strains We used Affymetrix microarray to explore the global gene expression patterns of mouse cerebral cortex of different mouse strains at two developmental stages
Project description:<p><strong>BACKGROUND:</strong> The protozoan parasite Toxoplasma gondii infects and alters the neurotransmission in cerebral cortex and other brain regions, leading to neurobehavioral and neuropathologic changes in humans and animals. However, the molecules that contribute to these changes remain largely unknown.</p><p><strong>METHODS:</strong> We have investigated the impact of T. gondii infection on the overall metabolism of mouse cerebral cortex. Mass-spectrometry-based metabolomics and multivariate statistical analysis were employed to discover metabolomic signatures that discriminate between cerebral cortex of T. gondii-infected and uninfected control mice.</p><p><strong>RESULTS:</strong> Our results identified 73, 67 and 276 differentially abundant metabolites, which were involved in 25, 37 and 64 pathways at 7, 14 and 21 days post-infection (dpi), respectively. Metabolites in the unsaturated fatty acid biosynthesis pathway were upregulated as the infection progressed, indicating that T. gondii induces the biosynthesis of unsaturated fatty acids to promote its own growth and survival. Some of the downregulated metabolites were related to pathways, such as steroid hormone biosynthesis and arachidonic acid metabolism. Nine metabolites were identified as T. gondii responsive metabolites, namely galactosylsphingosine, arachidonic acid, LysoSM(d18:1), L-palmitoylcarnitine, calcitetrol, 27-Deoxy-5b-cyprinol, L-homophenylalanine, oleic acid and ceramide (d18:1/16:0).</p><p><strong>CONCLUSIONS:</strong> Our data provide novel insight into the dysregulation of the metabolism of the mouse cerebral cortex during T. gondii infection and have important implications for studies of T. gondii pathogenesis.</p>
Project description:The cerebral cortex is a pivotal structure that is integral to advanced brain functions within the mammalian central nervous system. Patterns of DNA methylation and hydroxymethylation play important roles in regulating cerebral cortex development. However, it remains unclear whether abnormal cerebral cortex development, such as microcephaly, could rescale the epigenetic landscape, potentially contributing to dysregulated gene expression during brain development. In this study, we characterize and compare the DNA methylome/hydroxymethylome and transcriptome profiles of the cerebral cortex across several developmental stages in wild-type (WT) mice and Mcph1 knockout (Mcph1-del) mice with severe microcephaly. Intriguingly, we discover a global reduction of 5'- hydroxymethylcytosine (5hmC) level, primarily in TET1-binding regions, in Mcph1-del mice compared to WT mice during juvenile and adult stages. Notably, genes exhibiting diminished 5hmC levels and concurrently decreased expression are essential for neurodevelopment and brain functions. Additionally, genes displaying a delayed accumulation of 5hmC in Mcph1-del mice are significantly associated with the establishment and maintenance of the nervous system during the adult stage. These findings reveal that aberrant cerebral cortex development in early stages can profoundly alter the epigenetic regulation program, which provides new insights into the molecular mechanisms underpinning diseases related to cerebral cortex development.
Project description:This SuperSeries is composed of the following subset Series: GSE27459: Human cerebral cortex DNA methylation by MeDIP-Chip GSE27460: Rhesus macaque cerebral cortex DNA methylation profiling by MeDIP-Chip Refer to individual Series