Project description:Longitudinal analysis of Salmonella typhimurium mRNA from superspeader mouse cecal content and stool compared to in vitro Salmonella typhimurium mRNA.
Project description:Susceptibility to depression-like behavioral abnormalities in mice is studied with a well-established social defeat stress model. Responses to social defeat are associated with widespread transcriptomic changes in several brain regions. Here we present the first study of genome-wide cytosine methylation patterns of mice susceptible to social defeat stress using whole-genome bisulfite sequencing on DNA from the nucleus accumbens, a key brain reward region implicated in depression. We find a greater proportion of CpG hypermethylation than hypomethylation in susceptible mice compared to controls, with an opposite trend in the CHG and CHH contexts. Among the genes with the largest extent of differential methylation we find several which have been identified in earlier studies of gene expression changes related to social defeat, including estrogen receptor alpha (encoded by Esr1) and the deleted in colorectal cancer (Dcc) gene. Genes exhibiting differential methylation are enriched in GO terms of nervous system development, neurogenesis and structure development, which associated with learning memory and stress response. Our data provide a new evidence of the association of DNA methylation profiles and susceptibility to chronic stress.
Project description:In order to better understand the effects of social stress on the prefrontal cortex, we investigated gene expression in mice subjected to acute and repeated social encounters of different duration using microarrays. The observed up-regulation of genes associated with vascular system and brain injury suggests that stressful social encounters may affect brain function through the stress-induced dysfunction of the vascular system. We studied gene expression profiles of prefrontal cortices of male mice subjected to social stress of different durations: Comparisons included: acute stress (24 hours after single social stress episode) vs. acute control (unstressed), stress-8 days vs. control-8 days, stress-13 days vs. control-13 days, stress-13 days+5 days of rest vs. control-13 days+5 days of rest. For each comparison, we analyzed 3 biological replicates per group. Two of out of three biological replicates were further replicated in dye swap (final dye swap failed due to problem during microarray hybridization). Each biological replicate consisted of equal amounts of total RNA from 3 mice subjected to the same experimental condition.
Project description:Social play is a frequently studied behavior and it is the most characteristic form of social interaction observed in adolescent rats. Social play is necessary for adolescents to develop proper cognitive, emotional, and social competency. Deficits in social play have been observed in several neurodegenerative disorders such as autism, schizophrenia, and attention deficit hyperactivity disorder. However, the information available on neural substrates and the mechanism involved in social play is still limited. This study characterized social play by proteomic and transcriptional profiling studies. Social play was performed on male Sprague Dawley rats on postnatal day 38 and protein and gene expression in the amygdala was determined following behavioral testing. The proteomic analysis led to the identification of 170 differentially expressed proteins (p≤0.05) with 67 upregulated and 103 downregulated proteins. The transcriptomic analysis led to the identification of 188 genes (adjusted p≤0.05) with 55 upregulated and 133 downregulated genes. Based on both protein and gene expression data, DAVID analysis revealed that social play altered neurotransmitter signaling including GABAergic and glutamatergic signaling and G-protein coupled receptor (GPCR) signaling. These data suggest that the synaptic levels of GABA and glutamate increased during play. Ingenuity Pathway Analysis (IPA) confirmed these alterations. IPA also revealed that differentially expressed genes/proteins in our data had significant over representation of additional neurotransmitter signaling systems, including the opioid, serotonin, and dopamine systems, suggesting that play alters the systems involved in the regulation of reward. In addition, corticotropin-releasing hormone signaling was altered indicating that an increased level of stress occurs during play. Our data suggest that increased inhibitory GPCR signaling in these neurotransmitter pathways occurs following social play as a physiological response to regulate the induced level of reward and stress and to maintain the excitatory-inhibitory balance in the neurotransmitter systems.
Project description:Social stress is well known to be involved in the occurrence and exacerbation of mental illness, and also various life-style related diseases such as hyperinsulinemia, hyperglycemia, cardiovascular diseases and cancer. However, there is little information on tissue-specific gene expression in response to social stress, which reflects our daily life. Liver is one of the most important organs, owing to its biological functions such as energy metabolic homeostasis, metabolization and detoxification of endo- and exogenous substances. In order to elucidate the mechanism underlying response to social stress in the liver, we investigated hepatic gene expression in mice exposed to isolation stress using DNA microarray. Male BALB/c mice (4 weeks old) were housed 5 per cage for 10 days acclimatization. Then mice were exposed to isolation stress for 30 days. After stress treatment, the mouse liver RNA was subjected to DNA microarray analysis. Taking the false discovery rate into account, isolation stress altered expression of 420 genes. Moreover, Gene Ontology analysis of these differentially expressed genes indicated that isolation stress remarkably down-regulated lipid metabolism-related pathway through peroxisome proliferator-activated receptor-ï¡ (PPARï¡), while lipid biosynthesis pathway regulated by sterol regulatory element binding factor-1 (SREBF-1), Golgi vesicle transport and secretory pathway-related genes were significantly up-regulated. These results suggested that isolation for 30 days, mild and consecutive social stress, not only regulate the systems for lipid metabolism but also cause the endoplasmic reticulum stress in mouse liver. Experiment Overall Design: Male BALB/c mice (4 weeks old, Japan SLC, Shizuoka, Japan) weighing 14-18 g were housed 5 per cage. After acclimatization for 10 days, the mice were exposed to isolation (1 mouse per cage). All cages were placed in a foam plastic box in order to avoid social contact. To enhance the feeling of isolation, the bed volume in each cage for the isolated mice was reduced to one-tenth of that in the control group. The weight of bedding chips was about 2 g. All mice were housed in an air-conditioned room ( room temperature: 23 ± 1°C, humidity: 55 ± 5 %) under 12 h dark/12 h light cycles, with free access to tap water and MF diet (Oriental Yeast Co., Tokyo, Japan).
Project description:Life stress can shorten lifespan and increase risk for aging-related diseases, but the biology underlying this phenomenon remains unclear. We assessed the effect of chronic stress on cellular senescence — a hallmark of aging. Exposure to restraint stress, a psychological non-social stress model, increased p21Cip1 exclusively in the brains of male, but not female mice, and in a p16Ink4a-independent manner. Conversely, exposure to chronic subordination stress (CSS; males only were tested) increased key senescent cell (SNC) markers in peripheral blood mononuclear cells, adipose tissue and brain, in a p16Ink4a-dependent manner. p16Ink4a-positive cells in the brain of CSS-exposed mice were primarily hippocampal and cortical neurons with evidence of DNA damage that could be reduced by p16Ink4a cell clearance. Clearance of p16Ink4a-positive cells was not sufficient to ameliorate the adverse effects of social stress on measured metrics of healthspan. Overall, our findings indicate that social stress induces an organ-specific and p16Ink4a-dependent accumulation SNCs, illuminating a fundamental way by which the social environment can contribute to aging.
Project description:This study aimed to investigate the effects of depression on transcriptome in ileum using a subchronic and mild social defeat stress (sCSDS) model. In addition to exhibiting social deficit and hyperphagia-like behavior, the sCSDS mice keep much more water in their body than control mice. In order to investigate the effect of social defeat stress on not only central nervous system but also function of gastrointestinal tract, the gene expression in ileum of stressed mice was compared with control mice. We used microarrays to detail the gene expression after 10 days of social defeat stress and identified distinct classes of down-regulated genes during this process. The duration of physical contacts was set at 5 min after the first attack bite at Day 1, and then was reduced 0.5 min per day from Day 2 to Day 10.
Project description:Social stress is well known to be involved in the occurrence and exacerbation of mental illness, and also various life-style related diseases such as hyperinsulinemia, hyperglycemia, cardiovascular diseases and cancer. However, there is little information on tissue-specific gene expression in response to social stress, which reflects our daily life. Liver is one of the most important organs, owing to its biological functions such as energy metabolic homeostasis, metabolization and detoxification of endo- and exogenous substances. In order to elucidate the mechanism underlying response to social stress in the liver, we investigated hepatic gene expression in mice exposed to isolation stress using DNA microarray. Male BALB/c mice (4 weeks old) were housed 5 per cage for 10 days acclimatization. Then mice were exposed to isolation stress for 30 days. After stress treatment, the mouse liver RNA was subjected to DNA microarray analysis. Taking the false discovery rate into account, isolation stress altered expression of 420 genes. Moreover, Gene Ontology analysis of these differentially expressed genes indicated that isolation stress remarkably down-regulated lipid metabolism-related pathway through peroxisome proliferator-activated receptor-alpha (PPARalpha), while lipid biosynthesis pathway regulated by sterol regulatory element binding factor-1 (SREBF-1), Golgi vesicle transport and secretory pathway-related genes were significantly up-regulated. These results suggested that isolation for 30 days, mild and consecutive social stress, not only regulate the systems for lipid metabolism but also cause the endoplasmic reticulum stress in mouse liver.