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 SamplesPurpose: MicroRNA-21 contributes to the pathogenesis of fibrogenic diseases in multiple organs including the kidney. To evaluate the therapeutic utility of antimiR-21 oligonucleotides in chronic kidney disease, we silenced miR-21 in mice that develop Alport Nephropathy due to a defect in the Col4a3 gene. The goals of this study to assess the effect of inhibiting miR-21 in the Col4a3-/- Alport Syndrome mouse model at 5.5 weeks of age. Methods: Col4a3-/-, Col4a3+/-, and Col4a3+/+ mice in the 129X1/SvJ genetic background were obtained. Mice received anti–miR-21 (25 mg/kg) or control anti-miR (25mg/kg) in phosphate-buffered saline (PBS) by inter-scapular subcutaneous injection twice per week. In some experiments mice received a range of doses from 12.5mg/kg once a week to 50mg/kg once a week. Anti–miR-21 is a high-affinity oligonucleotide complementary to the active site of miR-21. Mice received injections starting at 24 days (3.5 weeks) after birth and ending at 5, 7, 9 or 16 weeks after birth depending on the study objectives. Total RNA from kidney tissue was extracted as per manufacturer’s instructions (miREASY kit, Qiagen). RNA quality was assessed using BioAnalyzer (Agilent). mRNA expression profiles were determined using next-generation sequencing (NGS) on the Illumina HiSeq 2000 platform producing 50bp paired-end reads. Bowtie/TopHat suites were used to align the reads to mouse genome or transcriptome and RSEM were used to quantify gene abundances. Gene level counts were then normalized with the R/Bioconductor package limma using the voom/variance stabilization method. Results: Anti-miR-21 enhanced PPARa/RXR activity and associated downstream signaling pathways in glomerular, tubular and interstitial cells, enhanced mitochondrial function, which reduced mitochondrial ROS production and preserved tubular cell functions. In addition, inhibition of miR-21 reduced fibrogenic and inflammatory signaling in glomerular and interstitial cells, likely as a consequence of enhanced PPARa/RXR activity and mitochondrial function. Inhibition of miR-21 represents a novel therapeutic strategy for chronic kidney diseases including Alport Nephropathy. Overall design: Whole kidney mRNA profiles of Col4a3+/- (triplicate) and Col4a3-/- (quadruplicates) mice treated with either PBS or antimiR-21, ending at 5.5 weeks of age, were generated by Next Generation Sequencing using Illumina HiSeq 2000
Anti-microRNA-21 oligonucleotides prevent Alport nephropathy progression by stimulating metabolic pathways.
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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.
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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 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 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.
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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.
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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 SamplesRhesus monkey extraocular muscle. Data set includes: (a) whole medial and lateral rectus muscle and (b) global and orbital muscle layers separately microdissected using a Leica LSM. All samples were expression profiled here using the Affymetrix human U133 A&B arrays. Data form part of publication: Investigative Ophthalmology and Visual Science 45, 2004.
Genome-wide transcriptional profiles are consistent with functional specialization of the extraocular muscle layers.
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