Heme utilization in the Caenorhabditis elegans hypodermal cells is facilitated by HRG-2
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ABSTRACT:
ORGANISM(S): Caenorhabditis elegans
PROVIDER: GSE34471 | GEO | 2013/01/01
SECONDARY ACCESSION(S): PRJNA151347
REPOSITORIES: GEO
Similar Datasets
Project description:The roundworm Caenorhabditis elegans is a heme auxotroph that requires the coordinated actions of HRG-1 heme permeases to transport environmental heme into the intestine and HRG-3, a secreted protein, to deliver intestinal heme to other tissues including the embryo. Here we show that heme homeostasis in the extraintestinal hypodermal tissue is facilitated by the transmembrane protein HRG-2. Systemic heme deficiency upregulates hrg-2 mRNA expression over 200-fold in the main body hypodermal syncytium hyp 7. HRG-2 is a type I membrane protein which binds heme and localizes to the endoplasmic reticulum and apical plasma membrane. Cytochrome heme profiles are aberrant in HRG-2 deficient worms, a phenotype that is partially suppressed by heme supplementation. Heme-deficient yeast strain, ectopically expressing worm HRG-2, reveal significantly improved growth at submicromolar concentrations of exogenous heme. Taken together, our results implicate HRG-2 as a facilitator of heme utilization in the C. elegans hypodermis and provide a mechanism for regulation of heme homeostasis in an extraintestinal tissue. Two experimental groups: Group 1: three 4um Controls vs. three 4uM hrg-2 Mutants; Group 2: three 20um Controls vs. three 20uM hrg-2 Mutants
2013-01-01 | E-GEOD-34471 | biostudies-arrayexpress
Project description:Hemes are essential but potentially cytotoxic cofactors that participate in critical and diverse biological processes. Although the pathway and intermediates for heme biosynthesis have been well defined, the intracellular networks which mediate heme trafficking remain unknown. Caenorhabditis elegans and related helminths are natural heme auxotrophs requiring environmental heme for growth and development. We exploited this auxotrophy to identify HRG-1 and HRG-4 in C. elegans and show that they are essential for heme homeostasis and normal vertebrate development. We demonstrate that heme deficiency upregulates expression of hrg-4 and its evolutionarily conserved paralog hrg-1. Depletion of either HRG-1 or HRG-4 in worms results in disruption of organismal heme sensing and abnormal response to heme analogs. HRG-1 and HRG-4 are novel transmembrane proteins that bind heme and have evolutionarily conserved functions. Transient knockdown of hrg-1 in zebrafish leads to hydrocephalus, yolk tube malformations, and, most strikingly, profound defects in erythropoiesis - phenotypes that are fully rescued by worm HRG-1. These findings reveal unanticipated and conserved pathways for cellular heme trafficking in animals that defines the paradigm for eukaryotic heme transport. Uncovering the mechanisms of heme transport in C. elegans will provide novel insights into human disorders of heme metabolism and generate unique anthelmintics to combat worm infestations. Keywords: dose-response
2008-06-13 | GSE8696 | GEO
Project description:Hemes are essential but potentially cytotoxic cofactors that participate in critical and diverse biological processes. Although the pathway and intermediates for heme biosynthesis have been well defined, the intracellular networks which mediate heme trafficking remain unknown. Caenorhabditis elegans and related helminths are natural heme auxotrophs requiring environmental heme for growth and development. We exploited this auxotrophy to identify HRG-1 and HRG-4 in C. elegans and show that they are essential for heme homeostasis and normal vertebrate development. We demonstrate that heme deficiency upregulates expression of hrg-4 and its evolutionarily conserved paralog hrg-1. Depletion of either HRG-1 or HRG-4 in worms results in disruption of organismal heme sensing and abnormal response to heme analogs. HRG-1 and HRG-4 are novel transmembrane proteins that bind heme and have evolutionarily conserved functions. Transient knockdown of hrg-1 in zebrafish leads to hydrocephalus, yolk tube malformations, and, most strikingly, profound defects in erythropoiesis - phenotypes that are fully rescued by worm HRG-1. These findings reveal unanticipated and conserved pathways for cellular heme trafficking in animals that defines the paradigm for eukaryotic heme transport. Uncovering the mechanisms of heme transport in C. elegans will provide novel insights into human disorders of heme metabolism and generate unique anthelmintics to combat worm infestations. Experiment Overall Design: As a first-step toward understanding heme homeostasis at the molecular level, we performed genome-wide microarrays to identify genes that are transcriptionally regulated by heme. For microarray analysis, synchronized F2 larvae were re-inoculated in mCeHR-2 medium supplemented with 4, 20 or 500 uM hemin and harvested at the late L4 stage for mRNA prep and probe hybridization to Affymetrix C. elegans Whole Genome Expression Arrays. Total RNA from three biological replicates were used at each hemin concentration. Data from worms grown in mCeHR-2 medium with 4 and 500 uM hemin were compared to data from worms grown in 20 uM hemin. Microarray data were verified with Microarray Suite 5.0 (Affymetrix) and Robust Multichip Average Method (RMA, R package). Results from MAS 5.0 and RMA analyses provided with 375 genes that showed 1.6 fold change in 4 and 500 uM hemin when compared to data from 20 uM hemin samples. Statistical analyses identified changes in 375 genes from worms grown in either 4 or 500 µM heme (see Methods). The microarray results were validated by qRT-PCR (Supplementary Fig. 1) and the 375 heme-responsive genes were classified into eight categories based on their relative changes in gene expression (Table I). The data from the microarray study show that �1.9 % of genes in the worm genome are transcriptionally responsive to heme. Notably, of the 375 genes, 164 had some sequence identity in human genome databases at the amino acid level, and >90 % of the genes had no ascribed function in the C.
2008-10-18 | E-GEOD-8696 | biostudies-arrayexpress
Project description:Purpose: The goal of this study is to understand how dbl-1, which is made primarily in neurons, and hrg-7, which is exclusively made in the intestine, contribute to systemic heme homeostasis. Methods: mRNA profiles of late L4 dbl-1(nk3) and hrg-7(tm6801) mutant C. elegans fed OP50 E. coli or OP50 + 50µM heme were compared to mRNA profiles from wildtype (WT) broodmates. Profiles were generated with single-end 50 base reads obtained using Illumina’s HiSeq 2500. Bioinformatics quality control was performed followed by alignment of reads to the ce10 reference genome using Tophat2, version 2.1.0. We found differentially expressed genes using Cufflinks 2, version 2.2.1 with a cutoff of 0.05 on False Discovery Rate (FDR). Results: We found a substantial overlap of genes regulated by both dbl-1 and hrg-7, including 49 heme-responsive genes (hrgs) in low heme (OP50) and 11 hrgs in high heme (OP50 + 50µM). Additionally, our data indicate crosstalk between dbl-1 and hrg-7 signaling. dbl-1 directly regulates hrg-7 expression, while hrg-7 regulates three components of the dbl-1 signaling pathway. Conclusions: Our study demonstrates that communication between the neuron and intestine is essential for heme homeostasis. Specifically, we report that HRG-7 functions as a secreted signaling factor which communicates intestinal heme status with extraintestinal tissues by integrating a DBL-1/BMP -dependent response from the neurons to transcriptionally regulate genes involved in heme homeostasis. Cellular requirements for heme are fulfilled by a cell’s internal capacity to synthesize its own heme in a cell-autonomous manner. However, growing evidence in vertebrates predicts that cellular heme levels in animals are not only maintained by heme synthesis, but also by distally located proteins that could signal systemic heme requirements to an inter-organ heme trafficking network through cell-nonautonomous regulation. Using C. elegans, a genetically and optically amenable animal model for visualizing heme-dependent signaling, we show that HRG-7, an aspartic protease homolog, mediates inter-organ signaling between the intestine and neuron. Loss of hrg-7 results in robust expression of intestinal heme importers and, remarkably, this occurs even under heme replete conditions when such transporters are not normally expressed. HRG-7 functions as a secreted signaling factor, independent of a functional enzymatic active site, and communicates intestinal heme status with extraintestinal tissues by integrating a DBL-1/BMP -dependent response from the neurons to transcriptionally regulate intestinal heme homeostasis. Given the evidence indicating that mechanisms of heme transport are conserved across metazoa, it is conceivable that the cell-nonautonomous signaling framework that we uncovered in C. elegans may have functional relevance for inter-organ regulation of iron and heme metabolism in humans.
2017-03-24 | GSE76455 | GEO
Project description:Heme utilization in the Caenorhabditis elegans hypodermal cells is facilitated by HRG-2
| PRJNA151347 | ENA
Project description:C. elegans L4 hypodermal SLAM-ITseq
| PRJNA791382 | ENA
Project description:Heregulin beta-1 (HRG) is an extracellular ligand that activates mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-OH kinase (PI3K)/Akt signaling pathways through ErbB receptors. MAPK and Akt have been shown to phosphorylate the estrogen receptor (ER) at Ser-118 and Ser-167, respectively, thereby mimicking the effects of estrogenic activity such as estrogen responsive element (ERE)-dependent transcription. In the current study, integrative analysis was performed using two tiling array platforms, comprising histone H3 lysine 9 (H3K9) acetylation and RNA mapping, together with array comparative genomic hybridization (CGH) analysis in an effort to identify HRG-regulated genes in ER-positive MCF-7 breast cancer cells. Through application of various threshold settings, 333 (326 up-regulated and 7 down-regulated) HRG-regulated genes were detected. Prediction of upstream transcription factors (TFs) and pathway analysis indicated that 21% of HRG-induced gene regulation may be controlled by the MAPK cascade, while only 0.6% of the gene expression is controlled by ERE. A comparison with previously reported estrogen (E2)-regulated gene expression data revealed that only 12 common genes were identified between the 333 HRG-regulated (3.6%) and 239 E2-regulated (5.0%) gene groups. However, with respect to enriched upstream TFs, 4 common TFs were identified in the 14 HRG-regulated (28.6%) and 13 E2-regulated (30.8%) gene groups. These results indicated that while E2 and HRG may induce common TFs, the regulatory mechanisms that govern HRG- and E2-induced gene expression differ. Keywords: growth hormone response
2008-02-08 | GSE8471 | GEO
Project description:C. elegans L4 hypodermal RNA polymerase DamID
| PRJNA884838 | ENA
Project description:Sharing common ErbB/HER receptor signaling pathway, heregulin (HRG) induces differentiation of MCF-7 breast cancer cells while epidermal growth factor (EGF) elicits proliferation. Although the cell fate led by those two ligands was totally different, the gene expression profile in early transcription was unexpectedly qualitatively similar, suggesting that the gene expression in late transcription, not early transcription, may reflect a respect of ligand specificity. In this study, based on the data from time-course microarray of all human genes, we predicted and determined a series of transcription factors which may control HRG-specific timed-late transcription and cellular differentiation of MCF-7 cells. Validation analyses showed that one of activator protein 1 (AP-1) families appeared just after c-Fos expression, another AP-1 family partner, induced expression of another transcription factor through activation of AP-1 complex. Furthermore, expression of this transcription factors caused suppression of extracellular signal-regulated kinase (ERK) phosphorylation which is sustainedly regulated by HRG-initiated ErbB signaling. Overall, our analysis indicated an importance of formation of timed-transcriptional regulatory network and its function to control upstream signaling pathway through negative feedback for cellular differentiation. Keywords: growth hormone response, time course
2009-05-26 | GSE13009 | GEO
Project description:The evolutionarily conserved Wnt/?-catenin signaling pathway plays a fundamental role during metazoan development, regulating numerous processes including cell fate specification, cell migration, and stem cell renewal. Wnt ligand binding leads to stabilization of the transcriptional effector ?-catenin and upregulation of target gene expression to mediate a cellular response. During larval development of the nematode Caenorhabditis elegans, Wnt/?-catenin pathways act in fate specification of two hypodermal cell types, the ventral vulval precursor cells (VPCs) and the lateral seam cells. Because little is known about targets of the Wnt signaling pathways acting during larval VPC and seam cell differentiation, we sought to identify genes regulated by Wnt signaling in these two hypodermal cell types. We conditionally activated Wnt signaling in larval animals and performed cell type?specific "mRNA tagging" to enrich for VPC and seam cell?specific mRNAs, and then used microarray analysis to examine gene expression compared to control animals. Two hundred thirty-nine genes activated in response to Wnt signaling were identified, and we characterized 50 genes further. The majority of these genes are expressed in seam and/or vulval lineages during normal development, and reduction of function for nine genes caused defects in the proper division, fate specification, fate execution, or differentiation of seam cells and vulval cells. Therefore, the combination of these techniques was successful at identifying potential cell type?specific Wnt pathway target genes from a small number of cells and at increasing our knowledge of the specification and behavior of these C. elegans larval hypodermal cells.
2015-11-18 | GSE52747 | GEO