Dexamethasone Acutely Down-regulates Genes Involved in Steroidogenesis in Stallion Testes
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ABSTRACT: Three stallions were treated with 0.1 mg/kg dexamethasone i.v. while three control stallions received an equivalent volume of saline. Serum testosterone dropped 60% in treated stallions at 12 h post-injection. Testes were collected 12 h post-injection and assessed for differential gene expression. Adult stallions were acclimated to the clinic over a 10 day period, then treated 12 h prior to collection of testes. Differential gene expression in treated vs. control stallion testes
Project description:Indole is a bacterial signal secreted by pathogenic and commensal Escherichia coli in the stationary phase at high concentrations (~600 µM). Prior work from our lab has shown that indole decreases E. coli O157:H7 (EHEC) chemotaxis, motility, attachment to epithelial cells and biofilm formation. However, its effect on epithelial cells is not known. We hypothesized that indole induces gene expression changes in epithelial cells that lead to decreased pathogen colonization and infection. Changes in gene expression with the human enterocyte cell line HCT-8 exposed to indole suggested down-regulation of Toll-like receptor signaling and coordinated changes in Jak-STAT and p38 MAPK pathways. Corresponding changes in the expression of cytokines, chemokines, and their receptors also suggested that indole functions as a modulator of inflammation in intestinal epithelial cells. In addition, the expression of genes involved in tight junction organization (claudins, and tight junction proteins) and mucin production were also up-regulated by indole. Keywords: Inter-kingdom signaling interactions between human cells and bacterial signal indole Human intestinal epithelial cells were exposed to 1 mM indole for 4 h or 24 h. RNA was isolated from the control cells and cells exposed to indole for 4 h and 24 h. The experiments were performed in triplicate. A total of 9 microarrays were performed, three for each condition. The gene expression data was analyzed using significance analysis of microarrays (SAM) where a false discovery rate cut-off of 1% was used. The genes were then classified and importnat regulated pathways were reported.
Project description:We used DNA microarrays to identify discriminative gene signatures for the purpose of classifying n-3 PUFA-fed, carcinogen injected Sprague Dawley rats at the initiation and progression stages. Animals were assigned to three dietary treatments differeing only in the type of fat (corn oi/n-6 PUFA, fish oil/n-3 PUFA, or olive oli/n-9 monounsaturated fatty acid). The effects of diet on colonic mucosal gene expression signatures during tumor initiation with the progression of colon cancer. Each dietary lipid source exhibited its own unique transcriptional profile, as assessed by linear discriminant analysis. Applying this novel approach we identified the single genes and the two- to three-gene combinations that best distinguished the dietary treatment groups. For the chemoprotective fish oil diet, mediators of stem cell homeostasis, e.g., ephrin B1 and bone morphogenic protein 4, were the top-permorming gene classifiers. keywords: diet analysis 29 samples were analyzed. 10 samples had repeat arrays. No control or reference samples were included.
Project description:On going efforts are directed at understanding the mutualism between the gut microbiota and the host in breast-fed versus formula-fed infants. Due to the lack of tissue biopsies, no investigators have performed a global transcriptional (gene expression) analysis of the developing human intestine in healthy infants. As a result, the crosstalk between the microbiome and the host transcriptome in the developing mucosal-commensal environment has not been determined. In this study, we examined the host intestinal mRNA gene expression and microbial DNA profiles in full term 3 month-old infants exclusively formula fed (FF) (n=6) or breast fed (BF) (n=6) from birth to 3 months. Host mRNA microarray measurements were performed using isolated intact sloughed epithelial cells in stool samples collected at 3 months. Microbial composition from the same stool samples was assessed by metagenomic pyrosequencing. Both the host mRNA expression and bacterial microbiome phylogenetic profiles provided strong feature sets that clearly classified the two groups of babies (FF and BF). To determine the relationship between host epithelial cell gene expression and the bacterial colony profiles, the host transcriptome and functionally profiled microbiome data were analyzed in a multivariate manner. From a functional perspective, analysis of the gut microbiota's metagenome revealed that characteristics associated with virulence differed between the FF and BF babies. Using canonical correlation analysis, evidence of multivariate structure relating eleven host immunity / mucosal defense-related genes and microbiome virulence characteristics was observed. These results, for the first time, provide insight into the integrated responses of the host and microbiome to dietary substrates in the early neonatal period. Our data suggest that systems biology and computational modeling approaches that integrate “-omic” information from the host and the microbiome can identify important mechanistic pathways of intestinal development affecting the gut microbiome in the first few months of life. KEYWORDS: infant, breast-feeding, infant formula, exfoliated cells, transcriptome, metagenome, multivariate analysis, canonical correlation analysis 12 samples, 2 groups
Project description:We recently revealed that myeloid master regulator PU.1 directly represses metallothionein (MT)-1G through its epigenetic activity, but the functions of MT-1G in myeloid differentiation remain unknown. To clarify this, we established MT-1G-overexpressing acute promyelocytic leukemia NB4 (NB4MTOE) cells, and investigated whether MT-1G functionally contributes to all-trans retinoic acid (ATRA)-induced NB4 cell differentiation. Real-time PCR analyses demonstrated that the inductions of CD11b and CD11c and reductions in myeloperoxidase and c-myc by ATRA were attenuated in NB4MTOE cells. Since G1 arrest is a hallmark of ATRA-induced NB4 cell differentiation, we observed a decrease in G1 accumulation, as well as decreases in p21WAF1/CIP1 and cyclin D1 inductions, by ATRA in NB4MTOE cells. Nitroblue tetrazolium (NBT) reduction assays revealed that the proportions of NBT-positive cells were decreased in NB4MTOE cells in the presence of ATRA. Microarray analyses showed that the changes in expression of several myeloid differentiation-related genes (GATA2, azurocidin 1, pyrroline-5-carboxylate reductase 1, defensin-4, C-X3-C motif receptor 3, matrix metallopeptidase -8, S100 calcium-binding protein A12, neutrophil cytosolic factor 2 and oncostatin M) induced by ATRA were disturbed in NB4MTOE cells. Collectively, overexpression of MT-1G disturbs the proper differentiation of myeloid cells. The present study provides evidence that expression analysis of MT-1G in acute promyelocytic leukemia patients may be a good prediction marker to estimate the efficacy of ATRA. Cell culture and generation of MT-1G-overexpressing cells: To generate MT-1G-overexpressing cells and their control cells, the MT-1G expression vector and its parental pcDNA 3.1/myc-His(-) version A vector (Invitrogen) were transfected using a CLB-Transfection device (Lonza, Basel, Switzerland). NB4 clones stably transfected with the vectors were isolated by limiting dilution and selection with 400 µg/ml of neomycin in RPMI (Gibco BRL, Rockville, MD) containing 10% heat-inactivated fetal bovine serum (HIFBS). Cells were cultured under 5% CO2 at 37°C in a humidified atmosphere. Microarray analyses: MT-1G-overexpressing (NB4MTOE) cells and their control cells were seeded at a density of 1×105 cells/ml and treated with 1 µM all-trans retinoic acid (ATRA). The cells were harvested after 72 h and total cellular RNA was isolated from control (NB4pcDNA4, 6, 7) cells and NB4MTOE (NB4MT22, 23, 25) cells using an RNA Mini Purification Kit (Qiagen, Miami, FL) according to the manufacturer’s protocol. Aliquots containing 10 µg of RNA from each sample of control cells were mixed and used as controls. Similarly, 10 µg of RNA from each sample of NB4MTOE cells were mixed and used as NB4MTOE cells. The samples were subjected to microarray analyses using a CodeLink Human 54K Whole Genome Bioarray (Filgen, Nagoya, Japan).
Project description:We have demonstrated that fish oil/pectin (FO/P) diets protect against colon cancer compared to corn oil/cellulose (CO/C) by upregulating apoptosis and suppressing proliferation. To elucidate the mechanisms whereby FO/P diets induce apoptosis and suppress proliferation during the tumorigenic process, we analyzed the temporal gene expression profiles from exfoliated rat colonocytes. KEYWORDS: Fish oil/pectin, pectin, exfoliated colonocytes, gene expression, apoptosis, colon cancer, chemoprevention Rats consumed diets containing FO/P or CO/C and were injected with azoxymethane (AOM, 2x, 15 mg/kg BW, s.c.). Feces collected at the initiation, aberrant crypt foci (ACF), and tumor stages of colon cancer (24 h (n=20), 7 wk (n=37), and 28 wk (n=28) after AOM injection, respectively) was used for poly A(+) RNA extraction. Gene expression signatures were determined using Codelink arrays.
Project description:Background: Lymphotoxin signaling via the lymphotoxin-β receptor (LTβR) has been implicated in several biological processes, ranging from development of secondary lymphoid organs, maintenance of splenic tissue, host defense against pathogens, autoimmunity, and lipid homeostasis. The major transcription factor that is activated by LTβR crosslinking is NF-κB. Two signaling pathways have been described that result in the activation of classical p50-RelA and alternative p52-RelB NF-κB heterodimers. Results: Using microarray analysis, we investigated the transcriptional response downstream of the LTβR in mouse embryoni fibroblasts (MEF) and its regulation by the RelA and RelB subunits of NF-κB. We describe novel LTβR-responsive genes that are regulated by RelA and/or RelB. Interestingly, we found that the majority of LTβR-regulated genes require the presence of both RelA and RelB, suggesting significant crosstalk between the two NF-κB activation pathways. Gene Ontology (GO) analysis confirmed that LTβR-NF-κB target genes are predominantly involved in the regulation of immune responses. However, other biological processes, such as apoptosis/cell death, cell cycle, angiogenesis, and taxis were also regulated by LTβR signaling. Moreover, we show that activation of the LTβR inhibits the expression of a key adipogenic transcription factor, peroxisome proliferator activated receptor-γ (pparg), suggesting that LTβR signaling may interfere with adipogenic differentiation. Conclusions: Thus, microarray analysis of LTβR-stimulated fibroblasts revealed further insight into the transcriptional response of LTβR signaling and its regulation by the NF-κB family members RelA and RelB. Keywords: cell type comparison (wt vs relA-/- vs relB-/-) after genetic modification using a time course for each cell type (wt, relA-/-, relB-/-) two time points were analysed (0h as control and 10h) using 3 technical replicates resulting in 18 samples in total
Project description:The mouse incisor is a remarkable tooth that grows throughout the animalM-bM-^@M-^Ys lifetime. This continuous renewal is fueled by epithelial stem cells that give rise to ameloblasts, which generate enamel, and little is known about the function of specific miRNAs in this process. Here we describe the role of a novel Pitx2:miR-200c/141:Noggin regulatory pathway in dental epithelial cell differentiation. miR-200c repressed noggin, an antagonist of Bmp signaling. Pitx2 expression caused an up-regulation of miR-200c and chromatin immunoprecipitation (ChIP) assays revealed endogenous Pitx2 binding to the miR-200c/141 promoter. A positive feedback loop was discovered between miR-200c and Bmp signaling. miR-200c/141 induced expression of E-cadherin and the dental epithelial cell differentiation marker, amelogenin. In addition, miR-203 expression was activated by endogenous Pitx2 and targeted the Bmp antagonist Bmper to further regulate Bmp signaling. miR-200c/141 knockout mice showed defects in enamel formation with decreased E-cadherin and amelogenin expression and increased noggin expression. Our in vivo and in vitro studies reveal a multistep transcriptional program involving the Pitx2:miR-200c/141:Noggin regulatory pathway that is important in epithelial cell differentiation and tooth development. Lower incisors of 3-5 P0 WT and Pitx2-Cre;Dicer1 cKO mices from same litter were dissected and combined for RNA extraction. Two different litters were analyzed. For mRNA microarray, CodeLink Mouse Whole Genome chips (Applied Microarrays) were used according to manufacturerM-bM-^@M-^Ys instruction (done at Genomics Core of TAMU). miRNA from P0 Lower Incisor ameloblast and cervical loops.
Project description:Background: Constitutive activation of the alternative NF-?B pathway leads to marginal zone B cell expansion and disorganized spleen microarchitecture. Furthermore, uncontrolled alternative NF-?B signaling results in the development and progression of cancer. We aimed here to learn about the mechanisms how does the constitutively active alternative NF-?B pathway exert its effects in these malignant processes. Methodology/Principal Findings: To explore the consequences of constitutive alternative NF-?B activation on genome-wide transcription, we compared gene expression profiles of wild-type and NF-kB2/p100-deficient (p100-/-) primary mouse embryonic fibroblasts (MEFs) and spleens. Microarray experiments revealed 73 differentially regulated genes in p100-/- vs. wild-type MEFs. Chromatin immunoprecipitation (ChIP) assays showed in p100-/- MEFs direct binding of RelB and p52 to the promoter of the enpp2 gene encoding Enpp2/Autotaxin, a protein with an important role in lymphocyte homing and cell migration. Gene ontology analysis revealed upregulation of genes with anti-apoptotic/proliferative activity (enpp2, serpina3g, traf1, rrad), chemotactic/locomotory activity (enpp2, ccl8), and lymphocyte homing activity (enpp2, cd34). Most importantly, biochemical analyses of MEFs and gene expression analyses of mice indicated a crosstalk between classical and alternative NF-?B pathways. Conclusions/Significance: The present results show that uncontrolled alternative NF-?B signaling is further enhanced by classical NF-?B activation, indicating that p100 deficiency alone is insufficient for full induction of a subset of genes by the alternative NF-?B pathway. cell type comparison (wt vs p100-/-) after genetic modification
Project description:Helicobacter pylori (H. pylori) infection and excessive salt intake are known as important risk factors for stomach cancer in humans. However, interactions of these two factors with gene expression profiles during gastric carcinogenesis remain unclear. In this study, we established a mouse gastric tumor model combining a chemical carcinogen, H. pylori infection and a high-salt diet. The tumor incidence and multiplicity in N-methyl-N-nitrosourea-treated mice were significantly increased by combination of H. pylori with a high-salt diet. In addition, detailed examination indicated that excessive salt could regulate progression of gastric tumor. Global gene expression profiles in glandular stomach of the mouse model were investigated by cDNA microarray analysis, and 36 and 31 more than twofold up-regulated and down-regulated genes, respectively, were detected in the H. pylori-infection and high-salt diet combined group compared with the other groups. Quantitative RT-PCR confirmed significant over-expression of several candidate genes including Cd177, Reg3g, and Muc13. These results suggest that our mouse model combined with H. pylori infection and high-salt diet is useful for gene expression profiling in gastric carcinogenesis. Five- to six-week-old male C57BL/6J mice (CLEA Japan, Tokyo, Japan) were inoculated with Helicobacter pylori (Sydney strain 1) (Sample No. 2 and 4) or Brucella broth (Sample No. 1 and 3). The animals were administered 120 ppm N-methyl-N-nitrosourea (MNU) in their drinking water on alternate weeks (total exposure, 5 weeks). Mice were given basal diet (CE-2, CLEA Japan) (Sample No. 1 and 2) or high-salt diet containing 10% NaCl (Sample No. 3 and 4). At 40 weeks, the animals were subjected to deep anesthesia and laparotomy with excision of the stomach.
Project description:The ubiquitin-proteasome and autophagy-lysosome pathways are the two major routes for protein and organelle clearance. In skeletal muscle, both systems’ excessive activation induces severe muscle loss. Although altered proteasomal function has been observed in various myopathies, the specific role of proteasomal activity in skeletal muscle has not been determined by loss-of-function approaches. Here, we report that muscle-specific deletion of a crucial proteasomal gene, Rpt3, resulted in profound muscle atrophy and decrease in force. Rpt3 null muscles showed reduced proteasomal activity in early age, accumulation of basophilic structure, disorganization of sarcomere, and formation of vacuoles and concentric membranous structures in electronmicroscope. We also observed accumulation of ubiquitin, p62, LC3, TDP43, FUS and VCP proteins. Proteasomal activity is important to preserve muscle mass and to maintain myofiber integrity. Our results suggest that inhibition/alteration of proteasomal activity can contribute to myofiber degeneration and weakness in muscle disorders, such as inclusion body myositis, characterized by accumulation of abnormal inclusions. Tibialis anterior muscles from Rpt3 null and control mice. each 3 mice.