Project description:We search for developmental changes specific to humans by examining gene expression profiles in the human, chimpanzee and rhesus macaque prefrontal and cerebellar cortex. In both brain regions, developmental patterns were more evolved in humans than in chimpanzees. The major human specific genes in prefrontal cortex was enriched in neuronal functions and regulated by several transcription factors, which were previously implicated in regulation of neuronal functions. To confirm neuronal function of the human prefrontal cortex specific genes, we identifed response genes upon neuronal activation in mouse cortical neurons. Our results show that human specific genes are enriched in the response genes upon neuronal activation, implying the function of human prefrontal cortex specific genes in synaptic development. The cortical neurons from E15 mouse were isolated and cultured. We then exposed neurons to bicuculline (Bic), or potassium chloride (KCl), or without treatment. The cultured neurons under each group were hybridized to Agilent whole mouse genome oligo microarray (4x44k).
Project description:The mammalian cortex is the structural basis for learning, cognition, and movement coordination. Dysgenesis of axon dendrites and synapses in cortical neurons can hinder learning and cognitive development, leading to epilepsy. Transcription factor Otx1 plays an important role in the development of the morphology and electrophysiological activity of cortical neurons and is associated with the occurrence of epilepsy. Abnormal synaptic pruning has been proposed to be one of the molecular mechanisms underlying epilepsy. Otx1 mutant mice leads to defective axonal pruning and changes the excitability and synaptic connections of the cortical neurons. However, little is known about the molecular pathways through which the loss of Otx1 causes epilepsy. On this basis, we found that the density and morphology of dendritic spines and microglia in Otx1 mutant mice changed significantly. TMT analysis of synaptic proteins reveals that Otx1 regulates the structure and function of cortical neurons and synaptic characteristics by regulating microglia-mediated synaptic pruning through the complement system, which also has important theoretical significance and application value for effective prevention and treatment of epilepsy.
Project description:Two key paradigms for examining activity-dependent development of primary visual cortex (V1) involve either reduction of activity in both eyes via dark-rearing (DR) or imbalance of activity between the two eyes via monocular deprivation (MD).,Combining DNA microarray analysis with computational approaches, RT-PCR, immunohistochemistry and physiological imaging, we find that DR leads to (i) upregulation of genes subserving synaptic transmission and electrical activity, consistent with a coordinated response of cortical neurons to reduction of visual drive, and (ii) downregulation of parvalbumin, implicating parvalbumin-expressing neurons as underlying the delay in cortical maturation after DR. MD partially activates homeostatic mechanisms but differentially upregulates gene systems related to growth factors and neuronal degeneration, consistent with reorganization of connections after MD. A binding protein of Insulin-like Growth Factor 1 is highly upregulated after MD, and exogenous application of IGF1 prevents the physiological effects of MD on ocular dominance plasticity examined in vivo.
Project description:We search for developmental changes specific to humans by examining gene expression profiles in the human, chimpanzee and rhesus macaque prefrontal and cerebellar cortex. In both brain regions, developmental patterns were more evolved in humans than in chimpanzees. To distinguish whether the human specific developmental pattern represent novel human-specific developmental patterns or a shift in the timing of the existing patterns, we measured mRNA expression patterns in macaque brains from prenatal to neonatal. Our results show that the major human-specific developmental patterns identified in the PFC reflects an extreme shift in timing of synaptic development.
Project description:We search for developmental changes specific to humans by examining gene expression profiles in the human, chimpanzee and rhesus macaque prefrontal and cerebellar cortex. In both brain regions, developmental patterns were more evolved in humans than in chimpanzees. To distinguish whether the human specific developmental pattern represent novel human-specific developmental patterns or a shift in the timing of the existing patterns, we measured mRNA expression patterns in macaque brains from prenatal to neonatal. Our results show that the major human-specific developmental patterns identified in the PFC reflects an extreme shift in timing of synaptic development. Rhesus macaque post-mortem brain samples from the superior frontal gyrus region of the prefrontal cortex were collected. Six fetal and six newborn samples were used. RNA extracted from the dissected tissue was hybridized to Affymetrix® Human Gene 1.0 ST arrays.
Project description:We investigated molecular changes during human, chimpanzee, and rhesus macaque postnatal brain development at the transcriptome, proteome, and metabolome levels in two brain regions: the prefrontal cortex (PFC) that is involved in several human-specific cognitive processes, and the cerebellar cortex (CBC) that may be functionally more conserved. We find a nearly three-fold excess of human-specific gene expression changes in PFC compared to CBC. The most prominent human-specific mRNA expression pattern in the PFC is a developmental delay of approximately 5 years in the expression of genes associated with learning and memory, such as synaptic transmission and long-term potentiation. This pattern is supported by correlated changes in concentrations of proteins and the respective neurotransmitters and its magnitude is beyond the shift expected from the life-histories of the species. Mechanistically, it might be driven by change in timing of expression of four or more transcription factors. We speculate that delayed synaptic maturation in PFC may play a role in the emergence of human-specific cognitive abilities. Keywords: Age series Human, chimpanzee and rhesus macaque post-mortem brain samples from the cerebellar cortex were collected. The age ranges of the individuals in all three species covered the respective species' postnatal maturation period from infancy to old adulthood. RNA extracted from the dissected tissue was hybridized to Affymetrix® Human Gene 1.0 ST arrays. CBC samples.
Project description:To test the connection between the molecular mechanisms underlying autistic disorder and human cognitive evolution, we analyzed the gene expression changes taking place during prefrontal cortex development in autism patients and healthy controls, as well as non-human primates. We found the genes with expression changes in autism are significantly overlapped with genes showing human-specific developmental profile. A major pattern of the overlapped genes reflects the aberrant acceleration of synaptogenesis and synaptic maturation followed by premature synaptic pruning in the prefrontal cortex of autism patients. This pattern involves the same developmental program that controls human-specific extension of cortical synaptogenesis in healthy individuals. Taken together, these findings shed light on the molecular mechanisms underlying autistic phenotype and provide potential targets for clinical intervention.
Project description:Experience-dependent gene transcription is required for nervous system development and function. However, the DNA regulatory elements that control this program of gene expression are not well defined. Here we characterize the enhancers that function across the genome to mediate activity-dependent transcription in neurons. While ~12,000 putative activity-regulated enhancer sequences have previously been identified that are enriched for H3K4me1 and the histone acetyltransferase CBP, we find that this chromatin signature is not sufficient to distinguish which of these regulatory sequences are actively engaged in promoting activity-dependent transcription. We show here that a subset of H3K4me1/CBP positive enhancers that is enriched for H3K27 acetylation (H3K27ac) in vivo, and shows increased H3K27ac upon membrane depolarization of cortical neurons, function to regulate activity-dependent transcription. The function of many of these activity-regulated enhancers appears to be dependent on the binding of FOS, a protein that had previously been thought to interact primarily with the promoters of activity-regulated genes. Furthermore, many of these target genes in cortical neurons encode neuron specific proteins that regulate synaptic development and function. These findings suggest that FOS functions at enhancers to control activity-dependent gene programs that are critical for nervous system function, and provide a resource of activity-dependent enhancers that may give insight into genetic variation that contributes to brain development and disease. Genome-wide maps of H3K27ac and AP1 transcription factors (CFOS, FOSB, JUNB) before and after neuronal activity in mouse cortical neurons.
Project description:We investigated molecular changes during human, chimpanzee, and rhesus macaque postnatal brain development at the transcriptome, proteome, and metabolome levels in two brain regions: the prefrontal cortex (PFC) that is involved in several human-specific cognitive processes, and the cerebellar cortex (CBC) that may be functionally more conserved. We find a nearly three-fold excess of human-specific gene expression changes in PFC compared to CBC. The most prominent human-specific mRNA expression pattern in the PFC is a developmental delay of approximately 5 years in the expression of genes associated with learning and memory, such as synaptic transmission and long-term potentiation. This pattern is supported by correlated changes in concentrations of proteins and the respective neurotransmitters and its magnitude is beyond the shift expected from the life-histories of the species. Mechanistically, it might be driven by change in timing of expression of four or more transcription factors. We speculate that delayed synaptic maturation in PFC may play a role in the emergence of human-specific cognitive abilities. Keywords: Age series Human, chimpanzee and rhesus macaque post-mortem brain samples from the superior frontal gyrus region of the prefrontal cortex were collected. The age ranges of the individuals in all three species covered the respective species' postnatal maturation period from infancy to old adulthood. RNA extracted from the dissected tissue was hybridized to Affymetrix® Human Gene 1.0 ST arrays. PFC samples.
Project description:Shank2 is an abundant excitatory postsynaptic scaffolding protein implicated in neurodevelopmental disorders, including autism spectrum disorders (ASD), intellectual disability, developmental delay, and schizophrenia. Shank2-mutant mice with a homozygous deletion of exons 6 and 7 (Shank2-HM mice) show ASD-like behavioral deficits and altered synaptic functions, although little is known about how different brain regions contribute to Shank2-mutant phenotypes. Here we attempted transcriptomic analyses of the prefrontal cortex, hippocampus, and striatum in adult Shank2-heterozygous/HT and Shank2-homozygous/HM mice. The mutant cortex, hippocampus, and striatum displayed distinct sets of differentially expressed genes associated with neuronal and synaptic functions in a gene dosage-differential manner. Gene set enrichment analyses of cortical Shank2-HT transcripts revealed increased synaptic gene expression and transcriptomic changes that are opposite to those observed in ASD (reverse-ASD), whereas cortical Shank2-HM transcripts displayed decreased synaptic gene expression and ASD-like transcriptomic patterns. The hippocampal Shank2-HT transcripts displayed minimally altered synaptic gene expression and mixed ASD-like and reverse-ASD patterns, whereas the Shank2-HM-hippocampus showed increased synaptic gene expression and reverse-ASD patterns. The striatal Shank2-HT/HM transcriptomes were largely similar to the hippocampal transcriptomes, although the main changes were observed in cell-type-specific genes, unlike the hippocampal changes mainly involving ASD-related/risk genes. These results indicate that heterozygous and homozygous Shank2 deletions in mice lead to brain region- and gene dosage-differential transcriptomic changes.