Although localized to the mineralized matrix of bone, osteocytes are able to respond to systemic factors such as the calciotropic hormones 1,25(OH)2D3 and PTH. In the present studies, we examine the transcriptomic response to PTH in an osteocyte cell model and found that this hormone regulated an extensive panel of genes. Surprisingly, PTH uniquely modulated two cohorts of genes, one that was expressed and associated with the osteoblast to osteocyte transition and the other a cohort that was expressed only in the mature osteocyte. Interestingly, PTH's effects were largely to oppose the expression of differentiation-related genes in the former cohort, while potentiating the expression of osteocyte-specific genes in the latter cohort. A comparison of the transcriptional effects of PTH with those obtained previously with 1,25(OH)2D3 revealed a subset of genes that was strongly overlapping. While 1,25(OH)2D3 potentiated the expression of osteocyte-specific genes similar to that seen with PTH, the overlap between the two hormones was more limited. Additional experiments identified the PKA-activated phospho-CREB (pCREB) cistrome, revealing that while many of the differentiation-related PTH regulated genes were apparent targets of a PKA-mediated signaling pathway, a reduction in pCREB binding at sites associated with osteocyte-specific PTH targets appeared to involve alternative PTH activation pathways. That pCREB binding activities positioned near important hormone-regulated gene cohorts were localized to control regions of genes was reinforced by the presence of epigenetic enhancer signatures exemplified by unique modifications at histones H3 and H4. These studies suggest that both PTH and 1,25(OH)2D3 may play important and perhaps cooperative roles in limiting osteocyte differentiation from its precursors while simultaneously exerting distinct roles in regulating mature osteocyte function. Our results provide new insight into transcription factor-associated mechanisms through which PTH and 1,25(OH)2D3 regulate a plethora of genes important to the osteoblast/osteocyte lineage. Overall design: Fully differentiated IDG-SW3 cells were treated in biological triplicate with 100nM PTH for 24 hours prior to mRNA isolation and sequencing. Vehicle treated samples were previously published in GSE54783: http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1323967 http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1323968 http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1323969
The parathyroid hormone-regulated transcriptome in osteocytes: parallel actions with 1,25-dihydroxyvitamin D3 to oppose gene expression changes during differentiation and to promote mature cell function.
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View SamplesHuman T-cell development is less well studied than its murine counterpart due to the lack of genetic tools and the difficulty of obtaining cells and tissues. However, recent technological advances allow identification of the transcriptional landscape of differentiating human thymocytes. Here we report the gene expression profiles of 11 immature, consecutive T-cell developmental stages. The changes in gene expression of cultured stem cells on OP9-DL1 match those of ex vivo isolated human thymocytes. These analyses led us to define evolutionary conserved gene signatures that represent pre- and post- T-cell commitment stages. We found that loss of CD44 marks T-cell commitment in early CD7+CD5+CD45dim cells, before the acquisition of CD1a surface expression. The CD44-CD1a- post-committed thymocytes have initiated in frame TCR rearrangements and have completely lost the capacity to develop into myeloid, B- and NK-cells, unlike uncommitted CD44+CD1a- thymocytes. Therefore, loss of CD44 represents a previously unrecognized stage that defines the earliest committed T-cell population in the human thymus.
Loss of CD44<sup>dim</sup> Expression from Early Progenitor Cells Marks T-Cell Lineage Commitment in the Human Thymus.
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View SamplesTo massively identify genes that are up-regulated by Cd and in particular transporter genes which might transport peptides or oligopeptides.
The Arabidopsis nitrate transporter NRT1.8 functions in nitrate removal from the xylem sap and mediates cadmium tolerance.
Age, Specimen part
View SamplesPrecise spatiotemporal control of mRNA translation machinery is essential to proper development of highly complex systems like the neocortex. Here, we show that an RNA-binding protein, Hu antigen R (HuR), regulates both neocorticogenesis and specificity of neocortical translation machinery in a developmental stage-dependent manner in mice. Neocortical absence of HuR alters the phosphorylation states of the initiation and elongation factors of the core translation machinery. In addition, HuR regulates the temporally specific positioning of functionally related mRNAs into the active translation sites, the polysomes. HuR also determines the specificity of neocortical polysomes by defining their combinatorial composition of ribosomal proteins and initiation and elongation factors. For some of the HuR-dependent proteins, the association with polysomes depends on the eIF2 alpha kinase 4 (eIF2ak4), which associated with HuR in prenatal developing neocortices. Finally, we found that deletion of HuR prior to embryonic day 10 (E10) disrupts both neocortical lamination and formation of the main neocortical commissure, the corpus callosum. Our study identifies a crucial role for HuR in neocortical development as a translational gatekeeper for functionally related mRNA subgroups and polysomal protein specificity. Overall design: Cortex was dissected from WT and HuR cKO mouse pups at embryonic day 13 (E13) or the day of birth (P0).
Thalamic WNT3 Secretion Spatiotemporally Regulates the Neocortical Ribosome Signature and mRNA Translation to Specify Neocortical Cell Subtypes.
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View SamplesLMO2 overexpressing transgenic mouse models suggest an accumulation of immature T-cell progenitors in the thymus as main pre-leukemic event. The effects of LMO2 overexpression on human T-cell development in vivo, however, are unknown. Here we report studies of a humanized mouse model transplanted with LMO2 transduced human hematopoietic stem and progenitor cells. The effects of LMO2 overexpression were confined to the T-cell lineage although initially multipotent cells were transduced. Three effects of LMO2 on human T-cell development were observed: 1) a block at the DN/ISP stage, 2) an accumulation of CD4+CD8+ double positive CD3- cells and 3) an altered CD8/CD4 ratio with enhanced peripheral T lymphocytes
Overexpression of LMO2 causes aberrant human T-Cell development in vivo by three potentially distinct cellular mechanisms.
Specimen part
View SamplesWe report the gene expression profiles of germinal center B cells obtained by FACS analyses of normal human lymph nodes.
Identification and functional relevance of de novo DNA methylation in cancerous B-cell populations.
Specimen part
View SamplesTo gain more insight into initiation and regulation of T cell receptor (TCR) gene rearrangement during human T cell development, we analyzed TCR gene rearrangements by quantitative PCR analysis in nine consecutive T-cell developmental stages, including CD34+ lin- cord blood cells as a reference. The same stages were used for gene expression profiling using DNA microarrays.
New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling.
Specimen part
View SamplesT cells develop from progenitors that migrate from the bone marrow into the thymus. Thymocytes are subdivided roughly as being double negative (DN), double positive (DP), or single positive (SP), based on the expression of the CD4 and CD8 coreceptors. The DN stage is heterogeneous and can be subdivided into four distinct subsets in mice based on the expression of CD44 and CD25. In human, three distinct DN stages can be recognized: a CD34+CD38CD1a stage that represents the most immature thymic subset and the consecutive CD34+CD38+CD1a and CD34+CD38+CD1a+ stages. Human DN thymocytes mature via an immature single positive (ISP CD4+) and a DP stage into CD4+ or CD8+ SP T cells that express functional T cell receptors (TCR) and that exit the thymus. In this study, gene expression was measured in each of these nine stages.
New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling.
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View SamplesThe goal of this project was to characterize changes in gene expression in response to the anti-cancer agent sapphyrin PCI-2050. Cultured A549 human lung cancer cells were treated with sapphyrin PCI-2050 or actinomycin D, a known transcripitonal inhibitor. The gene expression profiles of drug-treated and control A549 cultures were determined using Human Genome U133 Plus 2.0 Arrays (Affymetrix, Santa Clara, CA). Further details are provided in our published manuscript: <http://www.molecular-cancer.com/content/6/1/9>.
Synthesis and biologic properties of hydrophilic sapphyrins, a new class of tumor-selective inhibitors of gene expression.
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View SamplesWe generated Ikk-KA/KA knock-in mice (KA/KA), in which an ATP binding site of Ikk Lys 44 was replaced by alanine. The knock-in mice develop severe skin lesions and begin to die after 6 to 10 months. We also found lung SCCs in some of the mice. To study lung SCC development, we stabilize the skin condition by crossing KA/KA with Lori.Ikk transgenic mice to generate KA/KA-Lori.Ikk mice, which 100% spontaneously developed lethal lung SCC at 4 to 6 months of age.
The pivotal role of IKKα in the development of spontaneous lung squamous cell carcinomas.
Age, Specimen part
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