Gene expression changes related to postnatal handling
Ontology highlight
ABSTRACT: Postnatal handling in rodents leads to decreased anxiety-like behavior in adulthood. We used microarrays to look at gene expression differences in the CA1 region of the hippocampus in female mice subjected to postnatal handling compared to controls.
Project description:Postnatal handling in rodents leads to decreased anxiety-like behavior in adulthood. We used microarrays to look at gene expression differences in the CA1 region of the hippocampus in female mice subjected to postnatal handling compared to controls. Experiment Overall Design: Balb c/J offspring were briefly separated from mothers for 15 minutes each morning on postnatal days 1-14 (handled group) or left undisturbed. At 8 weeks of age mice were tested in the open-field and light-dark behavioral paradigms to verify a handling-induced behavioral phenotype. 2 weeks after behavioral testing, animals were sacrificed and the CA1 region was microdissected. CA1 regions were stored at -20C in RNA later. RNA was extracted from 8 samples (4 handled and 4 non-handled) using Trizol. RNA was extracted from second group of animals (7 handled and 10 non-handled) using Qiagen RNA/DNA columns. All total RNA samples were double round amplied and labeled using standard Affymetrix protocols and hybridized to Mouse 430_2.0 arrays in parallel.
Project description:Cajal-Retzius (CR) cells are a transient neuron type that populate the postnatal hippocampus. The role of transient cell types and circuits have been vastly addressed in neocortical regions, but poorly studied in the hippocampus. To understand how CR cells persistence influences the maturation of hippocampal circuits, we specifically ablated CR cells from the postnatal hippocampus. We observed layer-specific changes in the dendritic complexity and spine density of CA1 pyramidal cells. We were able to identify significant changes in the expression levels of Latrophilin-2, a postsynaptic guidance molecule known for its role in the entorhinal-hippocampal connectivity. Those findings were supported by changes in the overall synaptic proteomic content in CA1 Stratum Lacunosum-Moleculare.
Project description:Genetically identical inbred mice exhibit substantial stable individual variability in exploratory behavior. We used microarrays to look at gene expression differences in the hippocampus in female mice separated by stable differences in exploratory behavior Experiment Overall Design: Balb c/J offspring were briefly separated from mothers for 15 minutes each morning on postnatal days 1-14 (handled group) or left undisturbed. At 8 weeks of age mice were tested in the open-field and light-dark behavioral paradigms to verify a handling-induced behavioral phenotype. 2 weeks after behavioral testing, animals were sacrificed and the CA1 region was microdissected. CA1 regions were stored at -20C in RNA later. RNA was extracted from 8 samples (4 handled and 4 non-handled) using Trizol. RNA was extracted from second group of animals (7 handled and 10 non-handled) using Qiagen RNA/DNA columns. All total RNA samples were double round amplied and labeled using standard Affymetrix protocols and hybridized to Mouse 430_2.0 arrays in parallel.
Project description:Purpose: During postnatal development the fetal skeletal muscle undergoes a rapid and dramatic transition to adult function through transcriptional and post-transcriptional mechanisms, including alternative splicing (AS) Methods:We performed RNA-seq for high-resolution analysis of transcriptome changes during postnatal mouse skeletal muscle development using RNA from gastrocnemius muscle from embryonic day 18.5, postnatal day 2 (PN2), PN14, PN28, adult (22 weeks). Results: We identified a novel role for AS in several cellular functions including calcium handling and membrane organization during postnatal skeletal muscle development. Furthermore, AS transitions within calcium handling genes are responsive to Celf1 and Mbnl1, RNA-binding proteins with developmentally regulated expression. Conclusions: We identified a novel role for AS in several functional categories during postnatal development including calcium handling, vesicular trafficking and cell junctions.
Project description:MAP kinase signaling has been implicated in brain development, long-term memory, and the response to antidepressants. Inducible Braf knockout mice enabled us to unravel a new role of neuronal MAPK signaling for emotional behavior. Braf mice that were induced during adulthood showed normal anxiety but increased depression-like behavior, in accordance with pharmacological findings. In contrast, the inactivation of Braf in the juvenile brain leads to normal depression-like behavior but decreased anxiety in adults. In these mutants we found no alteration of GABAergic neurotransmission but reduced neuronal arborization in the dentate gyrus. Analysis of gene expression in the hippocampus revealed nine downregulated MAPK target genes that represent candidates to cause the mutant phenotype. Our results reveal the differential function of MAPK signaling in juvenile and adult life phases and emphasize the early postnatal period as critical for the determination of anxiety in adults. Moreover, these results validate inducible gene inactivation as new valuable approach, allowing to discriminate between gene function in the adult and the developing postnatal brain.
Project description:The hippocampus is part of a brain network essential for memory function. Paradoxically, the hippocampus is also the brain structure that is most sensitive to hypoxic-ischemic episodes. Here we show that the expression of genes associated with glycolysis and glutamate metabolism in astrocytes and the coverage of excitatory synapses by astrocytic processes undergo significant decreases in the CA1 field of the monkey hippocampus during postnatal development. Given the established role of astrocytes in the regulation of glutamate concentration in the synaptic cleft, our findings indicate that a developmental decrease in astrocytic processes underlies the selective vulnerability of CA1 during hypoxic-ischemic episodes in adulthood, its decreased susceptibility to febrile seizures with age, as well as contribute to the emergence of selective, adult-like memory function. Regulation of gene expression in the postnatally developing hippocampus might contribute to the emergence of selective memory function. However, the mechanisms that underlie the co-regulation of expression of hundreds of genes in different cell types at specific ages in distinct hippocampal regions have yet to be elucidated. By performing genome-wide microarray analyses of gene expression in distinct regions of the monkey hippocampal formation during early postnatal development, we identified one particular group of genes exhibiting a down-regulation of expression, between birth and six months of age in CA1 and after one year of age in CA3, to reach expression levels observed at 6-12 years of age. Bioinformatics analyses using NCBI, miRBase, TargetScan, microRNA.org and Affymetrix tools identified a number of miRNAs capable of regulating the expression of these genes simultaneously in different cell types, i.e., in neurons, astrocytes and oligodendrocytes. Interestingly, sixty-five percent of these miRNAs are conserved across species, from rodents to humans; whereas thirty-five percent are specific to primates, including humans. In addition, we found that some genes exhibiting greater down-regulation of their expression were the predicted targets of a greater number of these miRNAs. In sum, miRNAs may play a fundamental role in the co-regulation of gene expression in different cell types. This mechanism is partially conserved across species, and may thus contribute to the similarity of basic hippocampal characteristics across mammals. This mechanism also exhibits a phylogenetic diversity that may contribute to more subtle species differences in hippocampal structure and function observed at the cellular level. Sixteen male rhesus monkeys (Macaca mulatta; four 1-day-olds, four 6-month-olds, four 1-year-olds and four 6-12-year-olds) were used for this study. Monkeys were injected with an overdose of sodium pentobarbital (50 mg/kg i.v., Fatal-Plus, Vortech Pharmaceuticals, Dearborn, MI) and the brain rapidly extracted. Five-millimeter thick slices of the brain were cut and stored overnight in RNAlaterä (Ambion, Austin, TX) at 4oC. Brain slices were then frozen in liquid nitrogen and re-sectioned at 100 µm for microdissection. Five hippocampal regions were microdissected, including the entorhinal cortex (all layers at the mid-rostrocaudal level; intermediate division, Ei), and all layers of the dentate gyrus, CA3, CA1 and subiculum at mid-rostrocaudal level of the body of the hippocampus (at the level of the lateral geniculate nucleus). Only the mid-transverse portion of each region was dissected to ensure the specificity of the sample. RNA was isolated with Trizol® and single stranded cDNA synthesized starting with 10 µg of total RNA. The sample from each region from each monkey was run on a separate chip, thus totaling 4 (animals per age) X 4 (ages) X 5 (regions) = 80 independent chips.
Project description:The hippocampus is part of a brain network essential for memory function. Paradoxically, the hippocampus is also the brain structure that is most sensitive to hypoxic-ischemic episodes. Here we show that the expression of genes associated with glycolysis and glutamate metabolism in astrocytes and the coverage of excitatory synapses by astrocytic processes undergo significant decreases in the CA1 field of the monkey hippocampus during postnatal development. Given the established role of astrocytes in the regulation of glutamate concentration in the synaptic cleft, our findings indicate that a developmental decrease in astrocytic processes underlies the selective vulnerability of CA1 during hypoxic-ischemic episodes in adulthood, its decreased susceptibility to febrile seizures with age, as well as contribute to the emergence of selective, adult-like memory function. Regulation of gene expression in the postnatally developing hippocampus might contribute to the emergence of selective memory function. However, the mechanisms that underlie the co-regulation of expression of hundreds of genes in different cell types at specific ages in distinct hippocampal regions have yet to be elucidated. By performing genome-wide microarray analyses of gene expression in distinct regions of the monkey hippocampal formation during early postnatal development, we identified one particular group of genes exhibiting a down-regulation of expression, between birth and six months of age in CA1 and after one year of age in CA3, to reach expression levels observed at 6-12 years of age. Bioinformatics analyses using NCBI, miRBase, TargetScan, microRNA.org and Affymetrix tools identified a number of miRNAs capable of regulating the expression of these genes simultaneously in different cell types, i.e., in neurons, astrocytes and oligodendrocytes. Interestingly, sixty-five percent of these miRNAs are conserved across species, from rodents to humans; whereas thirty-five percent are specific to primates, including humans. In addition, we found that some genes exhibiting greater down-regulation of their expression were the predicted targets of a greater number of these miRNAs. In sum, miRNAs may play a fundamental role in the co-regulation of gene expression in different cell types. This mechanism is partially conserved across species, and may thus contribute to the similarity of basic hippocampal characteristics across mammals. This mechanism also exhibits a phylogenetic diversity that may contribute to more subtle species differences in hippocampal structure and function observed at the cellular level.
Project description:To understand the consequences of chronic exposure to fluoxetine during postnatal life on global transcriptional changes withing the rat medial prefrontal cortex in adulthood. To understand the consequences of chronic exposure to fluoxetine during postnatal life on global transcriptional changes withing the rat medial prefrontal cortex in adulthood.
Project description:N6-Methyladenosine (m6A) and N6,2′-O-dimethyladenosine (m6Am) are abundant mRNA modifications that regulate transcript processing and translation. The role of both, here termed m6A/m, in the stress response in the adult brain in vivo are currently unknown. Here, we investigated the effect of gene deletion of Mettl3, a m6A methyltransferase, and Fto, a m6A and m6Am demethlyase, induced in adulthood in excitatory neurons of the CA1 and CA3 in the hippocampus (Nex-CreERT2 Mettl3 or Fto cKO) on the transcriptome of CA1 and CA3 as well as the transcriptomic response of the CA1 and CA3 transcriptome to fear conditioning.
Project description:MAP kinase signaling has been implicated in brain development, long-term memory, and the response to antidepressants. Inducible Braf knockout mice enabled us to unravel a new role of neuronal MAPK signaling for emotional behavior. Braf mice that were induced during adulthood showed normal anxiety but increased depression-like behavior, in accordance with pharmacological findings. In contrast, the inactivation of Braf in the juvenile brain leads to normal depression-like behavior but decreased anxiety in adults. In these mutants we found no alteration of GABAergic neurotransmission but reduced neuronal arborization in the dentate gyrus. Analysis of gene expression in the hippocampus revealed nine downregulated MAPK target genes that represent candidates to cause the mutant phenotype. Our results reveal the differential function of MAPK signaling in juvenile and adult life phases and emphasize the early postnatal period as critical for the determination of anxiety in adults. Moreover, these results validate inducible gene inactivation as new valuable approach, allowing to discriminate between gene function in the adult and the developing postnatal brain. Five male Braf-cko, six male homozygous Braf-flox littermates, six male heterozygous CamkII-Cre, and six male wildtype littermates were killed with CO2, the complete hippocampal tissue was prepared, and total RNA was extracted with the Trizol protocol. The integrity and quality of the RNA samples were analyzed with an RNA electrophoresis chip (RNA 6000 Nano Kit, Agilent, Boeblingen, Germany). RNA samples of high integrity and quality (RIN ≥ 7.5) were further processed with the TotalPrep RNA Amplification Kit (Ambion, Austin, TX, USA) and hybridized onto MouseWG-6 v1.1 Expression Bead-Chips (Illumina, San Diego, CA, USA) following manufacturer’s instructions. Data were analyzed using the software R (used packages: beadarray, limma, and vsn).