Human toxicogenomic studies to date have been of limited size, have mainly addressed exposures at the upper end of typical ranges of human exposure, and have often lacked precise, individual estimates of exposure. Previously, we identified genes associated with exposure to high (>10 ppm) levels of the leukemogen, benzene, through transcriptomic analyses of blood cells from small numbers of occupationally exposed workers. Here, we have expanded the study to 125 workers exposed to a wide range of benzene levels, including <1 ppm. Study design, and analysis with a mixed effects model, removed sources of biological and experimental variability and revealed highly significant widespread perturbation of gene expression at all exposure levels. Benzene is an established cause of acute myeloid leukemia (AML), and may cause one or more lymphoid malignancies in humans. Interestingly, acute myeloid leukemia was among the most significant pathways impacted by benzene exposure in the present study. Further, at most exposure levels, immune response pathways including T cell receptor signaling, B cell receptor signaling, and Toll like receptor signaling were impacted, providing support for the biological plausibility of an association between lymphoma and benzene exposure. We also identified a 16-gene expression signature modified by all levels of benzene exposure, comprising genes with roles in immune response, inflammatory response, cell adhesion, cell-matrix adhesion, and blood coagulation. Overall, these findings support, and expand upon, our current understanding of the mechanisms by which benzene may induce hematotoxicity, leukemia and lymphoma. Furthermore, this study shows that with good study design and analysis, transcriptome profiling of the blood of chemically-exposed humans can identify relevant biomarkers across a range of exposures and inform about potential associations with disease risks.
Global gene expression profiling of a population exposed to a range of benzene levels.
Sex, Age, Subject
View SamplesStudy of the tetrapod limb has contributed a great deal to our understanding of developmental pathways and how changes to these pathways affect morphology. Most data on tetrapod limb development is known from amniotes, with far less known about genetic mechanisms of limb development in amphibians. To better understand the mechanisms of limb development in anuran amphibians, we use cyclopamine to inhibit Hedgehog signaling at various stages of limb development in Xenopus. We use transcriptomic analysis following cyclopamine exposure to understand the downstream effects of Hedgehog inhibition on gene expression. We find many aspects of Hedgehog function appear to be conserved with respect to amniotes, including the responses of ptc genes, gremlin, bmp2, and the autoregulatory property of shh. We show that, as was proposed based on experiments in chick, Sonic hedgehog plays two distinct roles in limb development specification of digit number and specification of digit identity. In contrast to these points of conservation, we find that Hedgehog signaling is required for the maintenance of early limb bud outgrowth in Xenopus, a requirement not known for any other tetrapod.
Choosing the right path: enhancement of biologically relevant sets of genes or proteins using pathway structure.
No sample metadata fields
View SamplesSporadic early onset colorectal carcinoma (EOCRC) is a growing problem that remains poorly understood. Clinical specificities and mechanisms of tumorigenesis might be relevant to both diagnosis and treatment. In this prospective study, clinicopathological features, genomic and gene expression profiles of sporadic EOCRC were compared to other well defined groups of CRC.
Sporadic early-onset colorectal cancer is a specific sub-type of cancer: a morphological, molecular and genetics study.
Sex, Specimen part
View SamplesThe BET (bromodomain and extra terminal) protein family members including BRD4 bind to acetylated lysines on histones and regulate the expression of important oncogenes, e.g., MYC and BCL2. Here we demonstrate the sensitizing effects of the histone hyperacetylation inducing pan-histone deacetylase inhibitor (HDI) panobinostat (PS) on human AML blast progenitor cells (BPCs) to the BET protein inhibitor JQ1. Treatment with JQ1 but not its inactive enantiomer (R-JQ1) was highly lethal against AML BPCs expressing mutant NPM1c+ with or without co-expression of FLT3-ITD, or AML expressing MLL fusion oncoprotein. JQ1 treatment reduced binding of BRD4 and RNA polymerase II to the DNA of MYC and BCL2, and reduced their levels in the AML cells. Co-treatment with JQ1 and the HDAC inhibitor panobinostat (PS) synergistically induced apoptosis of the AML BPCs, but not of normal CD34+ hematopoietic progenitor cells. This was associated with greater attenuation of MYC and BCL2, while increasing p21, BIM and cleaved PARP levels in the AML BPCs. Co-treatment with JQ1 and PS significantly improved the survival of the NOD/SCID mice engrafted with OCI-AML3 or MOLM13 cells (p < 0.01). These findings highlight co-treatment with a BRD4 antagonist and an HDI as a potentially efficacious therapy of AML.
Highly active combination of BRD4 antagonist and histone deacetylase inhibitor against human acute myelogenous leukemia cells.
Specimen part
View SamplesIn theses experimetns we have analized the differential gene expression profile in human trabecular meshwork cells phagocytically challenged to E. coli and pigment under physiological and oxidative stress conditions using affymetrix microarrays
Up-regulated expression of extracellular matrix remodeling genes in phagocytically challenged trabecular meshwork cells.
Specimen part
View SamplesThe transmission of information about the photic environment to the circadian clock involves a complex array of neurotransmitters, receptors, and second messenger systems. Using laser capture microscopy and microarray analysis, a population of genes rapidly induced by light in the suprachiasmatic nucleus is identified.
Identification of novel light-induced genes in the suprachiasmatic nucleus.
No sample metadata fields
View SamplesWe induced mouse embryonic stem cells (ESCs) into B progenitors in in vitro culture. We previously reported that B cells derived from extra-embryonic yolks sac (YS) belong to innate-like B-1 cells, not conventional B-2 cells. Since ES cell differentiation into Blood lineage, it recapitulates YS hematopoiesis, we hypothesized that B cells produced by mouse ESCs belong to B-1 cells as well. We transplanted ESC-derived B-progenitor cells into immunodeficient mice and confirmed that ES-derived B cells differentiate into only B-1 and marginal zone B cells, not B-2 cells in vivo. We preformed gene expression profiles by RNA sequencing comparing ESC-derived, YS-derived, fetal liver derived, and adult bone marrow derived B progenitor cells to see their characteristics. Overall design: We compared gene expression profllings among B-1 progeniotors derived from ES, Yolk sac, and fetal liver, and B-2 progenitors from adult bone marrow. We isolated CD19+B220+ B-progenitor cells obtained from in vitro culture of mouse ES cells, yolk sac, and fetal liver (all B-1 biased) and bone marrow (B-2 biased) and performed RNA sequencing Please note that Flk1 is a marker of mesoderm that differentiate into endothelial cells and blood cells and VEcad (VE-cadherin) is a marker of endothelial cells. It is known that all hematopoietic cells are derived from lateral mesoderm (Flk1+) cells via endothelial phenotype (VE-cad+). Therefore, we differentiated ESCs into Flk1+ mesoderm or VEcad+ endothelial cells and isolated them by sorting (as indicated in the sample source name field), and replated them onto OP9-stromal cells that support B cell development.
Long-Term Engraftment of ESC-Derived B-1 Progenitor Cells Supports HSC-Independent Lymphopoiesis.
Specimen part, Subject
View SamplesDetermination of gene expression changes in hindlimb muscle (gastrocnemius/soleus) of mdx (dystrophin-deficient) mice at postnatal ages 7, 14, 23, 28, 56, and 112.
Dissection of temporal gene expression signatures of affected and spared muscle groups in dystrophin-deficient (mdx) mice.
No sample metadata fields
View SamplesAn important component of time course microarray studies is the identification of genes that demonstrate significant time-dependent variation in their expression levels. Until recently available methods for performing such significance tests required replicates of individual time points. This paper describes a replicate-free method that was developed as part of a study of the estrous cycle in the rat mammary gland in which no replicate data was collected.
Identifying significant temporal variation in time course microarray data without replicates.
No sample metadata fields
View SamplesDetermination of gene expression changes in extraocular muscle of mdx (dystrophin-deficient) mice at postnatal ages 14, 28, 56, and 112 days. 3 independent replicates/age/strain.
Dissection of temporal gene expression signatures of affected and spared muscle groups in dystrophin-deficient (mdx) mice.
No sample metadata fields
View Samples