Zebrafish embryo were analyzed at 30 and 60 % epiboly for changes in transcriptome of wild-type and MTspg mutant embryos
Zebrafish Pou5f1-dependent transcriptional networks in temporal control of early development.
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Purpose: The goals of this study were to identify the molecular alterations in the SCA1 inferior olive, and determine whether these changes are found in other affected tissues. Methods: mRNA profiling was conducted in two different SCA1 mouse models (Atxn1 154Q/2Q KI and ATXN1-82Q Tg), in two different affected tisues (inferior olive and cerebellum) during early disease initiation and progression (5 week and 12 week time-points). All analyses were conducted relative to appropriate wild-type controls. TopHat2 v2.1.0 was utilized to align reads to the mouse reference genome (mm10) before quantification and differential expression analysis with Cufflinks v2.2.1. Normalized expression values were generated using Cuffnorm. Results: Differentially regulated genes identified in the SCA1 inferior olive segregated into several enriched biological pathways, including the Defense Response at 12 weeks of age. Our study demonstrates that vulnerable tissues in SCA1 are not uniform in their gene expression changes, and express discrete and commonly enriched biological pathways. In addition, we found that brain region-specific differences occur early in disease initiation and progression at 5 weeks of age. Conclusions: The findings from this study suggest that different mechanisms of neurodegeneration are at work in the SCA1 inferior olive and cerebellum. Overall design: mRNA profiling was conducted on an Illumina HiSeq 2500. Three biological replicates were sequenced for each genotype (Atxn1 154Q/2Q KI mice and wild-type controls; ATXN1-82Q Tg mice and wild-type controls) in each brain region (inferior olive and cerebellum) at each time-point (5 weeks old and 12 weeks old), yielding a total of 48 biological samples.
Molecular pathway analysis towards understanding tissue vulnerability in spinocerebellar ataxia type 1.
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Motherhood involves a switch in natural rewards, whereby offspring become highly rewarding. Nucleus accumbens (NAC) is a key CNS region for natural rewards and addictions, but to date no study has evaluated on a large scale the events in NAC that underlie the maternal change in natural rewards. In this study we utilized microarray and bioinformatics approaches to evaluate postpartum NAC gene expression changes in mice. Modular Single-set Enrichment Test (MSET) indicated that postpartum (relative to virgin) NAC gene expression profile was significantly enriched for genes related to addiction and reward in 5 of 5 independently curated databases (e.g., Malacards, Phenopedia). Over 100 addiction/reward related genes were identified and these included: Per1, Per2, Arc, Homer2, Creb1, Grm3, Fosb, Gabrb3, Adra2a, Ntrk2, Cry1, Penk, Cartpt, Adcy1, Npy1r, Htr1a, Drd1a, Gria1, and Pdyn. ToppCluster analysis found maternal NAC expression profile to be significantly enriched for genes related to the drug action of nicotine, ketamine, and dronabinol. Pathway analysis indicated postpartum NAC as enriched for RNA processing, CNS development/differentiation, and transcriptional regulation. Weighted Gene Coexpression Network Analysis identified possible networks for transcription factors, including Nr1d1, Per2, Fosb, Egr1, and Nr4a1. The postpartum state involves increased risk for mental health disorders and MSET analysis indicated postpartum NAC to be enriched for genes related to depression, bipolar disorder, and schizophrenia. Mental health related genes included: Fabp7, Grm3, Penk, and Nr1d1. We confirmed via quantitative PCR Nr1d1, Per2, Grm3, Penk, Drd1a, and Pdyn. This study indicates for the first time that postpartum NAC involves large scale gene expression alterations linked to addiction and reward. Because the postpartum state also involves decreased response to drugs, the findings could provide insights into how to mitigate addictions.
Addiction and reward-related genes show altered expression in the postpartum nucleus accumbens.
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The transition from the non-maternal to the maternal state is characterized by a variety of CNS alterations that support the care of offspring. The septum (including lateral and medial portions) is a brain region previously linked to various emotional and motivational processes, including maternal care. In this study, we used microarrays (PLIER algorithm) to examine gene expression changes in the septum of postpartum mice and employed gene set enrichment analysis (GSEA) to identify possible regulators of altered gene expression. Genes of interest identified as differentially regulated with microarray analysis were validated with quantitative real-time PCR. We found that fatty acid binding protein 7 (Fabp7) and galanin (Gal) were downregulated, whereas insulin-like growth factor binding protein 3 (Igfbp3) was upregulated in postpartum mice compared to virgin females. These genes were previously found to be differentially regulated in other brain regions during lactation. We also identified altered expression of novel genes not previously linked to maternal behavior, but that could play a role in postpartum processes, including glutamate-ammonia ligase (Glul) and somatostatin receptor 1 (Sstr1) (both upregulated in postpartum). Genes implicated in metabolism, cell differentiation, or proliferation also exhibited altered expression. Unexpectedly, enrichment analysis revealed a high number of microRNAs, transcription factors, or conserved binding sites (177 with corrected P-value <0.05) that were significantly linked to maternal upregulated genes, while none were linked to downregulated genes. MicroRNAs have been linked to placenta and mammary gland development, but this is the first indication they may also play a key role in sculpting the maternal brain. Together, this study provides new insights into genes (along with possible mechanisms for their regulation) that are involved in septum-mediated adaptations during the postpartum period.
Gene expression changes in the septum: possible implications for microRNAs in sculpting the maternal brain.
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Coordinated gene expression changes across the CNS help to produce the mammalian maternal phenotype. Lateral septum (LS) is a brain region critically involved with aspects of maternal care, and we recently examined gene expression of whole septum (LS and medial septum) in selectively bred maternal mice. Here, we expand on the prior study by 1) conducting microarray analysis solely on LS in virgin and postpartum mice, 2) using outbred mice, and 3) evaluating the role of sensory input on gene expression changes. Large scale changes in genes related to neuronal signaling were identified, including nine GABAA receptor subunits (p<0.05). Subunits 4 and were downregulated in maternal LS, likely reflecting a reduction in the extrasynaptic, neurosteroid-sensitive 4/ containing receptor subtype. Conversely, subunits and were increased in maternal LS. Sixteen K+ channel related genes showed altered expression, as did dopamine receptors Drd1a and Drd2 (both downregulated), hypocretin receptor 1 (Hcrtr1), kappa opioid receptor 1 (Oprk1), and transient receptor potential channel 4 (Trpc4). Expression of a large number of genes linked to developmental processes or cell differentiation were also altered in postpartum LS, including chemokine (C-X-C) motif ligand 12 (Cxcl12), fatty acid binding protein 7 (Fabp7), plasma membrane proteolipid (Pllp), and suppressor of cytokine signaling 2 (Socs2). Additional genes that are linked to anxiety, such as glutathione reductase (Gsr), exhibited altered expression. Pathway analysis also identified changes in genes related to cyclic nucleotide metabolism, chromatin structure, and the Ras gene family. The sensory presence of pups was found to contribute to the altered expression of a subset of genes across all categories. This study suggests that both large changes in neuronal signaling and the possible terminal differentiation of neuronal and/or glial cells play important roles in producing the maternal state.
Large scale expression changes of genes related to neuronal signaling and developmental processes found in lateral septum of postpartum outbred mice.
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PTEN is thought to play a critical role in T cell activation by negatively regulating the PI3K signaling pathway important for cellular activation, growth, and proliferation. T cells from mice in which PTEN was conditionally deleted in the thymus were reported to display CD28-independent IL-2 production and relative resistance to anergy induction. However, such observations could have stemmed from alterations in T cell development due to early deletion in thymocytes. To directly eliminate PTEN in post-thymic T cells, we utilized CAR Tg x PTENflox/flox mice which enabled gene deletion using a Cre adenovirus in vitro. Gene expression profiling revealed a small subset of induced genes that were augmented upon PTEN deletion and T cell stimulation. Our results indicate that deletion of PTEN can augment the activation of post-thymic T cells. Nonetheless, PTEN inhibition may be a viable target for immune potentiation due to increased cytokine production by activated CD4+ cells.
Conditional deletion of PTEN in peripheral T cells augments TCR-mediated activation but does not abrogate CD28 dependency or prevent anergy induction.
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Zebrafish embryos have been proposed as an attractive alternative model system for hepatotoxicity testing.
A transcriptomics-based hepatotoxicity comparison between the zebrafish embryo and established human and rodent in vitro and in vivo models using cyclosporine A, amiodarone and acetaminophen.
Aim: Differentiation of cardiac fibroblasts (Fb) into myofibroblasts (MyoFb) is responsible for connective tissue buildup in myocardial remodeling. We examined reversibility of MyoFb differentiation. Methods and Results: Adult rat cardiac Fb were cultured on a plastic substratum providing mechanical stress, with conditions to obtain different Fb phenotypes. Fb spontaneously differentiated to proliferating MyoFb (p-MyoFb) with stress fiber formation decorated with alpha-smooth muscle actin (-SMA). Transforming growth factor-1 (TGF-1) promoted terminal differentiation into -SMA positive MyoFb showing near absence of proliferation i.e. non-p-MyoFb (2-fold increase in cell number after 12 days vs 11-fold for p-MyoFb). SD-208, a TGF--receptor-I kinase blocker, inhibited p-MyoFb differentiation as shown by stress fiber absence, low levels of -SMA protein expression, and high levels of proliferation (32-fold increase after 12 days). Fb seeded in collagen matrices induced no contraction, whereas p-MyoFb and non-p-MyoFb induced 2.5- and 4-fold contraction. Fb produced low levels of collagen and secreted high levels of IL-10. Non-p-MyoFb showed high collagen production and high MCP-1 and TIMP-1 secretion. Transcriptome analysis indicated differential gene expression between all phenotypes. Dedifferentiation of p-MyoFb, but not of non-p-MyoFb, was induced by SD-208 despite maintained stress, shown by stress fiber de-polymerization in 30% of p-MyoFb vs in 8% of non-p-MyoFb. Stress fiber de-polymerization could be induced by mechanical strain release in p-MyoFb and non-p-MyoFb (2 day culture in unrestrained 3-D collagen matrices). Only p-MyoFb showed true dedifferentiation after long-term 3-D culture. Conclusions: Both reduction in mechanical strain and TGF--receptor-I kinase inhibition can reverse p-MyoFb differentiation but not in non-p-MyoFb.
Reversible and irreversible differentiation of cardiac fibroblasts.
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Radiation is an established cause of thyroid cancer and growing evidence supports a role for H2O2 in spontaneous thyroid carcinogenesis. Little is known about the molecular programs activated by these agents in thyroid cells. We profiled the DNA damage response and cell death induced by -radiation (0.15Gy) and H2O2 (0.00250.3mM) in primary human thyroid cells and T-cells. While the two cell types had more comparable radiation responses, 3- to 10-fold more H2O2 was needed to induce detectable DNA damage in thyrocytes. At H2O2 and radiation doses incurring double-strand breaks (DSB), cell death occurred after 24hrs in T-cells, but not in thyrocytes. We next prepared thyroid and T-cells primary cultures from 8 donors operated for non-cancerous pathologies and profiled their genome-wide transcriptional response 4hr after: 1) exposure to 1 Gy radiation, 2) treatment with H2O2, or 3) no treatment. Two H2O2 doses were investigated, calibrated in each cell type as to elicit levels of single- and double-strand breaks equivalent to 1 Gy -radiation. The transcriptional responses of thyrocyte and T-cells to radiation were similar, involving DNA repair and cell death genes. In addition to this transcriptional program, H2O2 also upregulated antioxidant genes in thyrocytes, including glutathione peroxidases (GPx) at the DSB-inducing dose. By contrast, a transcriptional storm involving thousands of genes was raised in T-cells. Finally, we showed that GPx inhibition reduced the DNA damaging effect of H2O2 in thyrocytes. We conjecture that defects of anti- H2O2 protection could promote spontaneous thyroid cancers.
Comparative analysis of the thyrocytes and T cells: responses to H2O2 and radiation reveals an H2O2-induced antioxidant transcriptional program in thyrocytes.
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