Effects of MiR-451a on the Phagocytosis and Polarization of Macrophages

Macrophages are important member in tissue microenvironments and play diverse physiologic and pathologic roles. Leukemia associated macrophages (LAM) are a kind of specifically activated macrophages in leukemia microenvironment, which are different from M1, M2 and TAMs. We have reported the heterogeneities in gene expression profiles of LAMs. However, MicroRNA expression profiles of LAMs and regulatory mechanism are still unknown. Here, a MLL-AF9 induced mouse acute myeloid leukemia (AML) model was used, and LAMs in the spleen and bone marrow were sorted for microRNA sequencing. The microRNA expression profiles of LAMs in bone marrow and spleen in AML mice were different from macrophages from control mice. Based on the volcano plot, more than 100 microRNAs were differentially expressed in LAMs compared with macrophages in control mice. Next, five differentially expressed microRNAs were selected and verified by qRT-PCR in LAMs from spleen. The results showed that miR-451a and miR-155-5p in spleen LAMs were significantly upregulated in LAMs from spleen. Overexpression of miR-451a altered the morphology of macrophages, enhanced the phagocytic ability of macrophages, and promotes the expression of macrophage differentiation marker CD11b. Furthermore, overexpression of miR-451a had little effect on M0 macrophages, but increased the proliferation capacity of macrophages upon stimulation toward M1 or M2 phenotype. MiR-451a overexpressed-macrophages had higher level of iNOS when stimulated with LPS or IL-4 whereas there was no difference in the expression of IL-1β, IL-6, CD206 and Arg-1 between MiR-451a overexpressed-macrophages and control macrophage. Therefore, our data revealed the characteristics of the microRNA expression profile of LAMs for the first time, and verified the effect of miR-451a on macrophage in vitro. Disclosures No relevant conflicts of interest to declare.

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171 THE EFFECT OF TRICHOSTATIN A ON THE DEVELOPMENT AND THE GLOBAL GENE EXPRESSION PATTERNS IN MOUSE EMBRYOS DEVELOPING IN VITRO

Reproduction Fertility and Development ◽

10.1071/rdv20n1ab171 ◽

2008 ◽

Vol 20 (1) ◽

pp. 165

Author(s):

X. S. Cui ◽

X. Y. Li ◽

T. Kim ◽

N.-H. Kim

Keyword(s):

Gene Expression ◽

Trichostatin A ◽

Expression Profiles ◽

Expression Patterns ◽

Gene Expression Profiles ◽

Mouse Embryos ◽

Differentially Expressed ◽

Gene Expression Patterns ◽

Cell Stage

Trichostatin A (TSA) is an inhibitor of histone deacetylase and is able to alter gene expression patterns by interfering with the removal of acetyl groups from histones. The aim of this study was to determine the effect of TSA treatment on the development and gene expression patterns of mouse zygotes developing in vitro. The addition of 100 nm TSA to the culture medium did not affect the cleavage of mouse embryos (TSA treatment, 148/150 (99%) v. control, 107/107 (100%)); however, embryos that were treated with TSA arrested at the 2-cell stage (145/148, 98%). We estimated the number of nuclei in control and TSA-treated embryos by propidium iodide staining, taking into account the presence of any cells with two or more nuclei. At 62–63 h post-hCG stimulation, control zygotes had developed to the 4-cell stage and exhibited one nucleus in each blastomere, indicative of normal development. In contrast, we observed tetraploid nuclei in at least one blastomere in 20.8% (11/53) of the embryos that had been treated with TSA. At 28–29 h post-hCG stimulation (metaphase of the 1-cell stage), there was no difference in the mitotic index (as determined by analyzing the microtubule configuration) in the TSA group compared to the control group. At the 2-cell stage, however, we did not observe mitotic spindles and metaphase chromatin in embryos in the TSA treatment group compared to the controls. Interestingly, when embryos were cultured in TSA-free medium from 35 h post-hCG stimulation (S- or early G2-phase of the 2-cell stage) onward, almost all of them (47/50) developed to the blastocyst stage. In contrast, when embryos were cultured in TSA-free medium from 42 h post-hCG stimulation (middle G2-phase of the 2-cell stage) onward, they did not develop to the 4-cell stage. We used Illumina microarray technology to analyze the gene expression profiles in control and TSA-treated late 2-cell-stage embryos. Applied Biosystems Expression System software was used to extract assay signals and assay signal-to-noise ratio values from the microarray images. Our data showed that 897 genes were significantly (P < 0.05; 2-sample t-test) up- or down-regulated by TSA treatment compared to controls. Analysis using the PANTHER classification system (https://panther.appliedbiosystems.com) revealed that the 575 genes that were differentially expressed in the TSA group compared to the control were classified as being associated with putative biological processes or molecular function. Overall, in terms of putative biological processes, more nucleoside, nucleotide, and nucleic acid metabolism, protein metabolism and modification, signal transduction, developmental process, and cell cycle genes were differentially expressed between the TSA and control groups. In terms of putative molecular function, more nucleic acid-binding transcription factor and transferase genes were differentially expressed between the groups. The results collectively suggest that inhibition of histone acetylation in mouse embryos affects gene expression profiles at the time of zygotic genome activation, and this subsequently affects further development.

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Transcriptome profiling of peanut (Arachis hypogaea) gynophores in gravitropic response

Functional Plant Biology ◽

10.1071/fp13075 ◽

2013 ◽

Vol 40 (12) ◽

pp. 1249 ◽

Cited By ~ 7

Author(s):

Hai-fen Li ◽

Xiao-Ping Chen ◽

Fang-he Zhu ◽

Hai-Yan Liu ◽

Yan-Bin Hong ◽

...

Keyword(s):

Differentially Expressed Genes ◽

Arachis Hypogaea ◽

Molecular Mechanisms ◽

Carbon Fixation ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Pentose Phosphate ◽

Differentially Expressed ◽

Pcr Analysis

Peanut (Arachis hypogaea L.) produces flowers aerially, but the fruit develops underground. This process is mediated by the gynophore, which always grows vertically downwards. The genetic basis underlying gravitropic bending of gynophores is not well understood. To identify genes related to gynophore gravitropism, gene expression profiles of gynophores cultured in vitro with tip pointing upward (gravitropic stimulation sample) and downward (control) at both 6 and 12 h were compared through a high-density peanut microarray. After gravitropic stimulation, there were 174 differentially expressed genes, including 91 upregulated and 83 downregulated genes at 6 h, and 491 differentially expressed genes including 129 upregulated and 362 downregulated genes at 12 h. The differentially expressed genes identified were assigned to 24 functional categories. Twenty pathways including carbon fixation, aminoacyl-tRNA biosynthesis, pentose phosphate pathway, starch and sucrose metabolism were identified. The quantitative real-time PCR analysis was performed for validation of microarray results. Our study paves the way to better understand the molecular mechanisms underlying the peanut gynophore gravitropism.

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Molecular Determinants of Lymph Node Microenvironment Induced Host Immune Tolerance In CLL: Role for CAV1, PTPN6, and PKCβ In the Process

Blood ◽

10.1182/blood.v116.21.1367.1367 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1367-1367

Author(s):

Christine Gilling ◽

Amit Mittal ◽

Vincent Nganga ◽

Vicky Palmer ◽

Dennis D. Weisenburger ◽

...

Keyword(s):

Gene Expression ◽

Mouse Model ◽

Immune Tolerance ◽

Conflicts Of Interest ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Cell Receptor ◽

Differentially Expressed ◽

Expression Levels ◽

Aggressive Disease

Abstract Abstract 1367 Previously, we have shown that gene expression profiles (GEP) of CLL cells from lymph nodes (LN), bone marrow (BM), and peripheral blood (PB) are significantly different from each other. Among the major pathways associated with differential gene expression, a “tolerogenic signature” involved in host immune tolerance is significant in regulating CLL progression. The genes associated with the tolerogenic signature are significantly differentially expressed in patient LN-CLL compared to BM-CLL and PB-CLL, suggesting that LN-CLL cells induce this immune tolerance. From 83 differentially expressed genes identified by GEP that are associated with immune dysregulation, we selected eleven genes (CAV1, PTPN6, PKCb, ZWINT, IL2Ra, CBLC, CDC42, ZNF175, ZNF264, IL10, and HLA-G) for validation studies to determine whether these genes are also dysregulated in the Emu-TCL1 mouse model of CLL. The results demonstrate a trend of upregulation of these genes as determined by qRT-PCR in the LN-tumor microenvironment. To further evaluate the kinetics of selected gene expression during tumor progression, we determined the expression levels of Cav1, Ptpn6, and Pkcb at 12, 24, and 36 weeks of CLL development in the Em-TCL1 mouse model. We found that the expression of all three genes increased as a function of age, indicating a correlation of gene expression with disease progression. In addition, as CLL progressed in these mice there was a marked decrease in CD4+ and CD8+ T cells. The murine data were further validated using CLL cells from the same patients with indolent versus aggressive disease indicating a similar trend in expression as CLL progressed (n=4). Furthermore, patient data analyzed by Kaplan Meier analyses of the expression levels of the selected genes indicated a significant association between down-regulation of PTPN6 (p=0.031) and up-regulation of ZWINT (p<0.001) with clinical outcome as determined by a shorter time to treatment (p<0.05). Functional analysis by knockdown of CAV1 and PKCb in primary patient CLL cells determined by MTT assay showed a decrease in proliferation following knockdown of these genes (p<0.005). Protein-interaction modeling revealed regulation of CAV1 and PTPN6 by one another. Additionally, the PTPN6 protein regulates B cell receptor (BCR) signaling and subsequently the BCR regulates PKCb. Therefore, these data from both mice and humans with CLL, argue that an aggressive disease phenotype is paralleled by expression of genes associated with immune suppression. In particular, evidence presented here suggests, dysregulation of CAV1, PTPN6, ZWINT, and PKCb expression promotes CLL progression. Disclosures: No relevant conflicts of interest to declare.

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Changes in Gene Expression Profiles in Patients with 5q- Syndrome Caused by Lenalidomide Treatment

Blood ◽

10.1182/blood.v118.21.5023.5023 ◽

2011 ◽

Vol 118 (21) ◽

pp. 5023-5023

Author(s):

Monika Belickova ◽

Jaroslav Cermak ◽

Jitka Vesela ◽

Eliska Cechova ◽

Zuzana Zemanova ◽

...

Keyword(s):

Gene Expression ◽

Differentially Expressed Genes ◽

Conflicts Of Interest ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Differentially Expressed ◽

Aurora A ◽

Genes Expression ◽

Marrow Stroma ◽

Cell Niche

Abstract Abstract 5023 A direct effects of lenalidomide on gene expression in 5q- patients was studied using HumanRef-8 v2 Expression BeadChips (Illumina). Expression profiles of 6 patients (before treatment and at the time of the first erytroid response) and 6 healthy controls were investigated from CD14+ monocytes of peripheral blood. Differentially expressed genes were identified by Significance Analysis of Microarrays (SAM). Simultaneously, selected genes (TNF, JUN, IL1) were monitored in the course of treatment using Real-Time PCR with Taqman Gene Expression Assays. A comparison of gene expression levels before and during lenalidomide treatment revealed 97 differentially expressed genes (FC >2; p<0.05) related to following biological processes: immune response (16 genes), inflammatory response (11 genes), response to bacteria (8 genes), anti-apoptosis (7 genes), regulation of MAP kinase activity (5 genes), oxygen transport (4 genes), and regulation of cell proliferation (11 genes). An overexpression of a number of cytokines (e.g. TNF, IL8, IL1B, CCL3L, CXCL2, and TNFAIP3) was detected in patients before treatment, after lenalidomide administration expression of the majority of the up-regulated cytokine genes decreased to the control baseline level. Detected overproduction of the cytokines in 5q- syndrome may lead to an increased apoptosis of hematopoietic progenitor cells and together with excessive oxidative stress may contribute to the damage the hematopoietic niche. In the same manner, untreated patients showed suppressed expression of two genes (CXCR4, CRTAP) which play an important role in the stem cell niche. After treatment, we detected increased expression of these genes. Both the observations might explain favorable effects of lenalidomide on the bone marrow stroma defect seen in 5q- syndrome. On the other hand, a substantial increase of the ARPC1B gene (an activator and a substrate of Aurora A) expression was detected after lenalidomide treatment. Since overexpression of Aurora A leads to polyploidy and chromosomal instability, ARPC1B might play a role in the disease progression observed in some patients treated with lenalidomide. To conclude, described changes in genes expression may contribute to identification of the pathways affected by lenalidomide and to the explanation of some effects of this drug that have not been fully understood yet. Supported by grants NS/9634 MZCR, UHKT2005 00023736, MSM0021620808 and COST EUGESMA Disclosures: No relevant conflicts of interest to declare.

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Trascriptome Analysis of Bone Marrow CD14+ Monocytes Revealed Differential Expression Profiles in Symptomatic Multiple Myeloma (MM) Compared to Smoldering MM and Monoclonal Gammopathy of Undetermined Significance

Blood ◽

10.1182/blood.v120.21.1811.1811 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1811-1811

Author(s):

Marco Peronaci ◽

Paola Storti ◽

Domenica Ronchetti ◽

Luca Agnelli ◽

Marina Bolzoni ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Differentially Expressed Genes ◽

Monoclonal Gammopathy ◽

Conflicts Of Interest ◽

Expression Profiles ◽

Differentially Expressed ◽

Potential Candidate ◽

Molecular Alterations ◽

Potential Candidate Gene

Abstract Abstract 1811 Symptomatic multiple myeloma (MM), smoldering MM (SMM) and monoclonal gammopathy of uncertain significance (MGUS) are well known different pathological and clinical entities of plasma cell (PC) disorders. Nevertheless molecular studies performed on clonal CD138+ PC do not clear distinguished these disorders that share common alterations. Studies focusing on the presence of potential molecular alterations in the microenvironment cells are ongoing. Because monocytes are the cells primarily involved in osteoclastogenesis, angiogenesis and immune system disfuction, that are the hallmark of symptomatic MM compared to SMM and MGUS, in this study we have analyzed the transcriptional profile of the bone marrow (BM) CD14+ cells in these settings of patients. BM CD14+ monocytes were purified from a total cohort of 36 patients with PC disorders including 21 patients with symptomatic MM, 8 patients with SMM and 7 patients with MGUS. CD14+ cells were isolated from the CD138 negative fraction of BM samples of patients by immunomagnetic method with anti-CD14 monoclonal antibody conjugated with microbeads. The presence of potential haemopoietic and CD138+ contaminating cells was excluded by FACS analysis. Only samples with CD14 purity greater than 95% were analyzed by microarrays by GeneChip® HG-U133Plus 2.0 arrays (Affymetrix®) (13 MM, 8 SMM and 7 MGUS). Data obtained were then validated on selected genes by Real-Time quantitative PCR. A multiclass analysis identified 14 differentially expressed genes, which characterized MGUS vs SMM vs symptomatic MM. A supervised analysis between symptomatic MM vs. SMM and MGUS samples identified 101 genes differentially expressed in CD14+ (58 genes up-regulated in MM vs SMM and MGUS and 43 genes donwregulated). Interestingly, among the differentially expressed genes we found that cytokines and cytokine receptors (IL21, IL21R, IL15, IL15R), chemokines (CXCL10, CXCL11) and interferon-inducible proteins (IFI27, IFI44) were up-regulated in CD14+ of MM patients as compared to SMM and MGUS. A supervised analysis between MM and MGUS identified 6 differentially expressed genes in CD14+ whereas 37 genes distinguished MM and SMM patients. Notably the SLAMF7 (CS1) gene recently indentified as a therapeutic target in CD138+ MM cells was up-regulated in CD14+ monocytes of MM patients as compared either to MGUS alone or to MGUS plus SMM could be a potential candidate gene. Overall our preliminary results indicate that a different transcriptional fingerprint may be identified in BM CD14+ cells of patients with symptomatic MM as compared to those with indolent PC disorders such as SMM and MGUS with a greater number of differentially expressed genes between symptomatic MM and SMM patient rather than between MM and MGUS. Disclosures: No relevant conflicts of interest to declare.

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Dexamethasone and lenalidomide have distinct functional effects on erythropoiesis

Blood ◽

10.1182/blood-2010-11-318543 ◽

2011 ◽

Vol 118 (8) ◽

pp. 2296-2304 ◽

Cited By ~ 52

Author(s):

Anupama Narla ◽

Shilpee Dutt ◽

J. Randall McAuley ◽

Fatima Al-Shahrour ◽

Slater Hurst ◽

...

Keyword(s):

Bone Marrow ◽

Expression Profiles ◽

Bone Marrow Failure ◽

Gene Expression Profiles ◽

Absolute Number ◽

Red Blood Cell Transfusion ◽

Erythroid Progenitor ◽

Diamond Blackfan Anemia ◽

Cd34 Cells

Abstract Corticosteroids and lenalidomide decrease red blood cell transfusion dependence in patients with Diamond-Blackfan anemia (DBA) and myelodysplastic syndrome (MDS), respectively. We explored the effects of dexamethasone and lenalidomide, individually and in combination, on the differentiation of primary human bone marrow progenitor cells in vitro. Both agents promote erythropoiesis, increasing the absolute number of erythroid cells produced from normal CD34+ cells and from CD34+ cells with the types of ribosome dysfunction found in DBA and del(5q) MDS. However, the drugs had distinct effects on the production of erythroid progenitor colonies; dexamethasone selectively increased the number of burst-forming units-erythroid (BFU-E), whereas lenalidomide specifically increased colony-forming unit-erythroid (CFU-E). Use of the drugs in combination demonstrated that their effects are not redundant. In addition, dexamethasone and lenalidomide induced distinct gene-expression profiles. In coculture experiments, we examined the role of the microenvironment in response to both drugs and found that the presence of macrophages, the central cells in erythroblastic islands, accentuated the effects of both agents. Our findings indicate that dexamethasone and lenalidomide promote different stages of erythropoiesis and support the potential clinical utility of combination therapy for patients with bone marrow failure.

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The transcriptional landscape of the murine middle ear epithelium in vitro

10.1101/800987 ◽

2019 ◽

Author(s):

Apoorva Mulay ◽

Md Miraj K Chowdhury ◽

Cameron James ◽

Lynne Bingle ◽

Colin D Bingle

Keyword(s):

Gene Expression ◽

Middle Ear ◽

In Vitro Model ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Inflammatory Cells ◽

Differentially Expressed ◽

Vitro Model ◽

Transcriptional Landscape

AbstractOtitis media (OM) is the most common paediatric disease and leads to significant morbidity. Although understanding of underlying disease mechanisms is hampered by complex pathophysiology, it is clear that epithelial abnormalities underpin the disease. The mechanisms underpinning epithelial remodelling in OM remain unclear. We recently described a novel in vitro model of mouse middle ear epithelial cells (mMEECs) that undergoes mucociliary differentiation into the varied epithelial cell populations seen in the middle ear cavity. We now describe genome wide gene expression profiles of mMEECs as they undergo differentiation. We compared the gene expression profiles of original (uncultured) middle ear cells, confluent cultures of undifferentiated cells (day 0 of ALI) and cells that had been differentiated for 7 days at an ALI. >5000 genes were differentially expressed among the three groups of cells. Approximately 4000 genes were differentially expressed between the original cells and day 0 of ALI culture. The original cell population was shown to contain a mix of cell types, including contaminating inflammatory cells that were lost on culture. Approximately 500 genes were upregulated during ALI induced differentiation. These included some secretory genes and some enzymes but most were associated with the process of ciliogenesis. Our in vitro model of differentiated murine middle ear epithelium exhibits a transcriptional profile consistent with the mucociliary epithelium seen within the middle ear. Knowledge of the transcriptional landscape of this epithelium will provide a basis for understanding the phenotypic changes seen in murine models of OM.

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An in Vitro Model of Differentiation of Memory B Cells Into Plasmablasts and Plasma Cells Including Detailed Phenotypic and Molecular Characterization.

Blood ◽

10.1182/blood.v114.22.1636.1636 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1636-1636

Author(s):

Michel Jourdan ◽

Anouk Caraux ◽

John De Vos ◽

Geneviève Fiol ◽

Marion Larroque ◽

...

Keyword(s):

B Cells ◽

In Vitro Model ◽

Plasma Cells ◽

Conflicts Of Interest ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Memory B Cells ◽

Vitro Model ◽

Intermediate Cells

Abstract Abstract 1636 Poster Board I-662 Human plasma cells (PCs) and their precursors play an essential role in humoral immune response, but are rare and difficult to harvest. We report here i) the generation of human syndecan-1+ and immunoglobulin secreting PCs starting from memory B cells (MBCs) in a 3-step- and 10-day (D) culture, including a 6-fold cell amplification. ii) We report the detailed phenotypic and Affymetrix gene expression profiles of these in vitro PCs as well as of intermediate cells - activated B cells (actBCs) and plasmablasts (PBs) - compared to MBCs and bone marrow PCs, which is accessible through an open web ATLAS (http://amazonia.transcriptome.eu/). iii) We show this B cell to PC differentiation to involve IRF4 and AICDA expression in D4 actBCs, decrease of PAX5 and BCL6 expressions and increase in PRDM1 and XBP1 expressions in D7 PBs and D10 PCs. It involves downregulation of genes controlled by Pax5, induction of genes controlled by Blimp-1 and XBP1 (unfold protein response). iv) The phenotype of D10 PCs resembles that of peripheral blood PCs detected after immunization of healthy donors. This in vitro model will facilitate further studies in PC biology. It will likewise be helpful to study plasma-cell dyscrasias, including Multiple Myeloma. Disclosures No relevant conflicts of interest to declare.

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PML-RARα Deregulates an Unexpectedly Small Number of Genes in Pre-Leukemic Promyelocytes

Blood ◽

10.1182/blood.v120.21.3526.3526 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3526-3526

Author(s):

Coline M Gaillard ◽

Taku A Tokuyasu ◽

Emmanuelle Passegué ◽

Scott C. Kogan

Keyword(s):

Bone Marrow ◽

Fusion Protein ◽

Conflicts Of Interest ◽

Fusion Gene ◽

Leukemic Cells ◽

Cytokine Signaling ◽

Proliferation Capacity ◽

Number Of Genes

Abstract Abstract 3526 Background: Acute Promyelocytic Leukemia (APL) is characterized by the accumulation in the blood and bone marrow of abnormal promyelocytes, which have the ability to transfer the disease to secondary recipients in animal models. The PML-RARα fusion protein is thought to be the primary abnormality implicated in the pathology, and is believed to prevent transcription of genes necessary for normal myeloid development and differentiation. Identifying PML-RARα targets is critical for understanding the road to leukemic transformation. However, such targets have so far been identified using cell line assays in vitro, murine cells differentiated into promyelocytes in vitro, or fully transformed murine or human leukemic cells. Focusing on the cell population in which the transforming potential is acquired, we describe here a novel strategy to identify the transcriptomic dysregulation induced by PML-RARα expression in maturing myeloid populations in vivo. Methods: We utilize a murine model of human APL in which the human PML-RARα fusion gene is expressed under the control of the MRP8 promoter, driving its expression in maturing myeloid populations. Those animals can be described as pre-leukemic since they eventually develop leukemia when additional mutations occur. Fresh bone marrows from normal (Fvb/n) or pre-leukemic (PML-RARα) animals were harvested. Using an improved cell surface antigen staining strategy and fluorescence-activated cell sorting, three populations of increasingly differentiated myeloid populations have been sorted (Granulocyte Macrophage Progenitor, Early promyelocyte and Late promyelocyte). RNA was extracted and submitted for whole-genome microarray analysis. In addition, we are using a variety of bioinformatics approaches to decipher the network of novel interactions driven by PML-RARα expression. Results: Markers used in our sorting strategy were validated in the dataset, including CD34 and Gr1. In the normal samples, markers of neutrophil maturation increased, largely as expected, and a number of early transcription factors decreased in an expected manner including Hoxa9 and Meis1. One remarkable finding was that despite the previously described ability of PML-RARα to regulate transcription from multiple sites in the genome, only a small number of genes were differentially impacted by the expression of this protein. Surprisingly, well-known regulators of myeloid differentiation that have been implicated in the retinoic acid responsiveness of APL including Sfpi1 (PU.1) and Cebpa were not differentially expressed. However, in pre-leukemic samples PML-RARα did cause decreased expression of multiple neutrophilic granule genes including Ltf, Mmp9 and Ngp. The gene most upregulated in the pre-leukemic samples was Spp1 which encodes the osteopontin phosphoprotein. Of interest, we identified the myeloid tumor suppressor Irf8 to be downregulated 5 fold in the presence of PML-RARα. To investigate the importance of IRF8 levels in APL initiation, we transplanted Irf8+/+ PML-RARα or Irf8+/− PML-RARα bone marrow into irradiated recipients. Despite the potential for decreased expression of IRF8 to contribute to APL, we observed no difference. This result does not confirm a role for IRF8 in APL pathogenesis, but further investigations are needed to exclude such a role. Bioinformatics studies highlighted enrichment in cell cycle-related genes upon PML-RARα expression, suggesting a possible difference in the proliferation capacity of the pre-leukemic cells, which is currently under investigation. Conclusions: We found that in vivo the transcriptome was only modestly dysregulated by the presence of PML-RARα. These observations open up new questions on the role of the fusion protein in pathogenesis: How does PML-RARα prime pre-leukemic cells for full transformation? How do secondary events allow an initiated cell to advance to a fully transformed state? Such questions are currently being investigated, with a special interest on looking at the cooperation between PML-RARα and activated cytokine signaling in leukemia initiation. Disclosures: No relevant conflicts of interest to declare.

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Gene expression profiles of RAW264.7 macrophages stimulated with preparations of LPS differing in isolation and purity

Innate Immunity ◽

10.1177/1753425910393540 ◽

2011 ◽

Vol 18 (1) ◽

pp. 80-88 ◽

Cited By ~ 14

Author(s):

Holly R Rutledge ◽

Weiwen Jiang ◽

Jun Yang ◽

Laura A Warg ◽

David A Schwartz ◽

...

Keyword(s):

Gene Expression ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Differentially Expressed ◽

Transcriptional Networks ◽

Molecular Pathways ◽

Raw264.7 Macrophages ◽

Lps Treatment

Lipopolysaccharide is a major component of the cell wall of Gram-negative bacteria and a potent stimulator of innate immune response via TLR4. Studies on the LPS action both in vivo and in vitro have used different preparations of LPS, including ultra-pure LPS (LIST) and a less pure but less expensive form (Sigma) isolated from Escherichia coli serotype O111:B4. The difference between the effects of these compounds has not been well studied although this information is important in understanding TLR stimulation. In this study, we compared response of RAW264.7 macrophage cells treated LIST or Sigma LPS for 6 h and 24 h. Gene expression data were analyzed to identify specific genes and pathways that are in common and unique to the two LPS preparations. Seven hundred fifty-five genes were differentially expressed at 6 h in response to Sigma LPS and 973 were differentially expressed following LIST LPS treatment, with 503 in common. At 24 h, Sigma LPS induced or repressed 901 genes while 1646 genes were differentially regulated by LIST LPS treatment; 701 genes were shared by two forms of LPS. Although considerably more genes were differentially expressed in response to LIST LPS, similar molecular pathways and transcriptional networks were activated by the two LPS preparations. We also treated bone marrow-derived macrophages (BMMs) from three strains of mice with different concentrations of LIST and Sigma LPS and showed that BMMs produced more IL-6 and TNF-α in response to LIST LPS at low LPS concentrations but, at higher LPS concentrations, more cytokines were produced in response to stimulation by Sigma LPS. Together, these findings suggest that, despite activation of similar molecular pathways by LIST and Sigma LPS preparations, residual protein impurities in the Sigma LPS preparation may nevertheless influence the transcriptional profile attributed to TLR4 stimulation.

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