Microarray characterization of Vhl; Vhl, Hif1a; Vhl, Hif2a and Vhl, Hif1a, Hif2a deficient primary kidney cells
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ABSTRACT: To unravel the potential cooperative roles of oxygen-regulated signaling pathways; von Hippel-Lindau (VHL) tumor suppressor protein and hypoxia-inducible factor (HIF) transcription factors, we have generated mutant mice with; Vhlh, Vhlh/Hif1α, Vhlh/Hif2α and Vhlh/Hif1α/Hif2α gene alleles floxed. Subsequently primary kidney cells were isolated, cultured and infected with Adenoviruses bearing either Cre/GFP or GFP expression only. Agilent cDNA microarrays were utilized to compare the gene expression profiles of the kidney epithelial cells from aforementioned cell cultures to gain insight about the molecules and signaling pathways that drive aberrant cellular proliferation in clear cell renal cell carcinoma (ccRCC). 24 independent biological samples from 4 genetic experimental conditions were hybridized in two- color format on 13 Mouse GE 4x44K v2 Microarray Kit (Design ID 026655) arrays. Eventual dye specific hybridization effects were controlled with dye swap on biological replicates. For an each experimental condition 3 arrays were use, except of one where 4 arrays were used (one sample combination in repetition with a dye swap). For the final analysis the gene expression levels were dye effect corrected and values for biological replicates were averaged to obtain a matrix with gene expression levels for 4 independent biological (1. Vhlh-/-, 2. Vhlh-/-/Hif1α-/-, 3. Vhlh-/-/Hif2α-/- and 4. Vhlh-/-/Hif1α-/-/Hif2α-/-) conditions.
Project description:To unravel the potential cooperative roles of oxygen-regulated signaling pathways; von Hippel-Lindau (VHL) tumor suppressor protein and hypoxia-inducible factor (HIF) transcription factors, we have generated mutant mice with; Vhlh, Vhlh/Hif1α, Vhlh/Hif2α and Vhlh/Hif1α/Hif2α gene alleles floxed. Subsequently primary kidney cells were isolated, cultured and infected with Adenoviruses bearing either Cre/GFP or GFP expression only. Agilent cDNA microarrays were utilized to compare the gene expression profiles of the kidney epithelial cells from aforementioned cell cultures to gain insight about the molecules and signaling pathways that drive aberrant cellular proliferation in clear cell renal cell carcinoma (ccRCC).
Project description:In this study, we explored the existence of a transcriptional network co-regulated by E2F7 and HIF1α, as we show that expression of E2F7, like HIF1α, is induced in hypoxia, and because of the previously reported ability of E2F7 to interact with HIF1α. Our genome-wide analysis uncovers a transcriptional network that is directly controlled by HIF1α and E2F7, and demonstrates both stimulatory and repressive functions of the HIF1α -E2F7 complex. Among this network we reveal Neuropilin 1 (NRP1) as a HIF1α-E2F7 repressed gene. By performing in vitro and in vivo reporter assays we demonstrate that the HIF1α-E2F7 mediated NRP1 repression depends on a 41 base pairs 'E2F-binding site hub', providing a molecular mechanism for a previously unanticipated role for HIF1α in transcriptional repression. To explore the biological significance of this regulation we performed in situ hybridizations and observed enhanced nrp1a expression in spinal motorneurons (MN) of zebrafish embryos, upon morpholino-inhibition of e2f7/8 or hif1α. Consistent with the chemo-repellent role of nrp1a, morpholino-inhibition of e2f7/8 or hif1α caused MN truncations, which was rescued in TALEN-induced nrp1a(hu10012) mutants, and phenocopied in e2f7/8 mutant zebrafish. Therefore, we conclude that repression of NRP1 by the HIF1α-E2F7 complex regulates MN axon guidance in vivo. The following samples were analyzed by microarrays: RNA isolated from HeLa cells transfected with either control (scr), E2F7, HIF1a, E2F7 and E2F8, or E2F7 and HIF1a siRNAs. Cells were harvested 48h after transfection, and were grown the last 16h in hypoxia. RNA isolated from scr-transfected, normoxic HeLa cells was used as common reference RNA. Within each group of two biological replicates, sample versus common reference hybridisations were performed in balanced dye-swap. Microarrays used were human whole genome gene expression microarrays V1 (Agilent, Belgium).
Project description:The thymus is a physiologically hypoxic organ and fulfills its role of generating T cells under low-oxygen conditions. We have therefore investigated how thymic epithelial cells (TECs) cope with physiological hypoxia by focusing on the role of the Hif1a-Vhl axis. In most cell types, the oxygen-labile transcriptional regulator Hif1a is a central player in co-ordinating responses to low oxygen: under normoxic conditions Hif1a is rapidly degraded in a Vhl-guided manner; however, under hypoxic conditions Hif1a is stabilized and can execute its transcriptional functions. Unexpectedly, we find that, although TECs reside in a hypoxic microenvironment, they express little Hif1a protein and do not require Hif1a for their development or function. Instead, we find that Vhl function in TECs is vital to constrain Hif1a activity, as loss of Vhl results in dramatic defects in TEC differentiation and thymopoiesis, which can be rescued by Hif1a co-depletion.
Project description:The posterior lateral line system in zebrafish involves cell migration, proliferation and differentiation into mechanosensory cells. During development, a group of cranial placodal cells delaminate and become a coherent, migratory primordium that traverses the length of the fish to form this sensory system. As they migrate, the primordium deposits groups of cells called neuromasts, the specialized organs that contain the mechanosensory hair cells. The lateral line hair cells of fish are related to inner ear hair cells; therefore the primordium provides both a model for studying collective directional cell migration and the differentiation of sensory cells from multipotent progenitor cells. Through the combination of transgenic fish, Fluorescence Activated Cell Sorting and microarray analysis we identified a repertoire of key genes expressed in the migrating primordium and in differentiated neuromasts. We validated the specific expression in the primordium of a subset of the identified sequences by quantitative RT-PCR, and by in situ hybridization. We also show that interfering with the function of f11r and cd9b induces defects in its migratory behavior. Finally, pathway construction revealed functional relationships among the genes enriched in the migrating cell population. Our results demonstrate that this is a robust approach to globally analyze specific expression and we predict that many of the genes identified in this study will show critical functions in developmental and tumor progression process relating to posterior lateral line development. The experiment was performed in two developmental stages, 36 and 48 hours post-fertilization. Two-condition experiment, GFP- (negative control) and GFP+ cells. Two biological repeats by stage, each by quadruplicate including a dye swap.
Project description:This study utilized oligonucleotide microarrays to examine gene expression profiles in pheochromocytomas from 23 patients; 11 VHL tumors and 12 MEN2 tumors. RNA was extracted and linearly amplified once, then dye-labeled and co-hybridized to a microarray with over 34,000 oligos representing more than 25,000 unique human genes. In validation of our strategy, many genes known to have elevated expression in MEN2 tumors (e.g., CALM1, CHGB, CABP1and NPY) and several genes known to be specific to VHL (e.g., AQP1) were independently identified by this approach. In addition to known genes, our method has identified several hundred of previously uncharacterized genes that are enriched in the MEN2 or VHL tumors.
Project description:Complete (whole) embryonic kidneys were dissected from wild type and Hoxa11, Hoxd11 compound null embryos throughout development. Targets from two biological replicates of each were generated and the expression profiles were determined using Affymetrix MOE430A and MOE430B arrays. Comparisons between normal and mutant and comparisons of development samples identified global patterns of gene regulation in kidney development Experiment Overall Design: Embryonic metanephric kidney samples throughout development were analyzed based on normalization to adult kidney samples. In addition, Hoxa11, Hoxd11 compound null embronic kidneys were normalized to wild type embryonic controls. All developmental and adult stages were represented in biological (seperate embryo/animal replicate).<br><br>Normalized data files were not included because there appears to be a mismatch between the composite sequence identifiers in some of them and the array design selected.
Project description:Estrogen is thought to have a role in slowing down aging and protecting cardiovascular and cognitive function. However, high doses of estrogen are still positively associated with autoimmune diseases and tumors with systemic inflammation. First, we administered exogenous estrogen to female mice for three consecutive months and found that the aorta of mice on estrogen develops inflammatory manifestations similar to Takayasu arteritis (TAK). Then, in vitro estrogen intervention was performed on mouse aortic vascular smooth muscle cells (MOVAS cells). Stimulated by high concentrations of estradiol, MOVAS cells showed decreased expression of contractile phenotypic markers and increased expression of macrophage-like phenotypic markers. This shift was blocked by tamoxifen and Krüppel-like factor 4 (KLF4) inhibitors and enhanced by Von Hippel-Lindau (VHL)/hypoxia-inducible factor-1α (HIF-1α) interaction inhibitors. It suggests that estrogen-targeted regulation of the VHL/HIF-1α/KLF4 axis induces phenotypic transformation of vascular smooth muscle cells (VSMC). In addition, estrogen-regulated phenotypic conversion of VSMC to macrophages is a key mechanism of estrogen-induced vascular inflammation, which justifies the risk of clinical use of estrogen replacement therapy.
Project description:Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell cancer, characterized by the highest mortality rate among other RCC subtypes due to the occurrence of metastasis and drug resistance following surgery. The Von Hippel‑Lindau tumor suppressor (VHL)‑hypoxia‑inducible factor 1 subunit α (HIF1A)/hypoxia‑inducible factor 2α (HIF2A)‑vascular endothelial growth factor A (VEGFA) protein axis is involved in the development and progression of ccRCC, whereas sunitinib, a tyrosine kinase inhibitor, blocks the binding of VEGFA to its receptor. The aim of the present study was to examine the possible association of the gene expression of VHL, HIF1A, HIF2A, VEGFA and tumor protein P53 (P53) in cancer tissue with the outcome of ccRCC patients who were treated with sunitinib as first‑line therapy following nephrectomy. A total of 36 ccRCC patients were enrolled, 11 of whom were administered sunitinib post‑operatively. Tumor and control samples were collected, and mRNA and protein levels were assessed by reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. High mRNA and protein expression levels of HIF2A and VEGFA were found to be associated with shorter overall survival (OS) and progression‑free survival (PFS) rates, as well as with unfavorable risk factors of cancer recurrence and mortality. Resistance to sunitinib was also observed; the OS and PFS rates were shorter (median OS and PFS: 12 and 6 months, respectively, vs. undetermined). Sunitinib resistance was associated with high HIF2A and VEGFA protein levels (b=0.57 and b=0.69 for OS and PFS, respectively; P<0.001). Taken together, the findings of this study suggest that the protein levels of HIF2A and VEGFA in tumor tissue may serve as independent prognostic factors in ccRCC. ccRCC patients with increased intratumoral HIF2A and VEGFA protein levels, and unaltered VHL protein levels, are not likely to benefit from sunitinib treatment following nephrectomy; however, this hypothesis requires verification by large‑scale replication studies.
Project description:Distinct metabolic programs support the differentiation of CD4+T cells into their separate lineages. In this study, we investigated metabolic mechanisms underlying the differentiation of IL-9 producing-CD4+T cells (TH9) in allergic airway inflammation and cancerous tumors. We found here that SIRT1 negatively regulates TH9 differentiation. A deficiency of SIRT1 induced by either conditional deletion in mouse CD4+T cells or the use of small interfering RNA (siRNA) in mouse or human T cells increased IL-9 production, whereas ectopic SIRT1 expression inhibited it. Notably, SIRT1-inhibited the differentiation of TH9 cells that regulated anti-tumor immunity and allergic pulmonary inflammation. Glycolytic activation through the mTOR-hypoxia-inducible factor-1α (HIF1α) pathway was required for the differentiation of the TH9 cells that confer protection against tumors and are involved in allergic airway inflammation. Our results define the essential features of a SIRT1-mTOR-HIF1α signaling-coupled glycolytic pathway in inducing TH9 cell differentiation, with implications for metabolic reprogramming as an immunotherapeutic approach. Lymphocytes were isolated from the spleen and lymph nodes of mice and sorted on a FACSAria II (Becton Dickinson). The sorted naïve T cells (CD4+TCR+CD62Lhi CD44lo) from WT or SIRT1flox/flox-CD4-Cre mice were used for in vitro culture. T cells were activated with 2 ug/ml anti-CD3 (2C11; Bio X Cell), 2 ug/ml anti-CD28 (37.51; Bio X Cell) and 100 U/ml human IL-2. For TH9 cell differentiation, cultures were supplemented with 10 ng/ml IL-4 (R&D system), 2 ng/ml TGFβ1 (R&D system). After 5-6 d culture, differentiated T cells were collected and for microarray assay.
Project description:During kidney development segmented epithelia of the nephron derive from progenitor cells in the metanephric mesenchyme after induction by secreted molecules from the ureteric bud. We have identified three distinct inductive activities from a ureteric bud cell line. These include leukemia inhibitory factor (LIF), neutrophil gelatinase-associated lipocalin (NGAL) and an active fraction currently referred to as ANX. Each of these activities induces segmented nephron epithelia in isolated rat metanephric mesenchyme over a time period of 7 days. This study was designed to characterize the temporal sequence of gene expression in the course of the conversion process induced by each of the distinct inducers. Experiment Overall Design: Metanephric mesenchymes were microdissected from rat E13.5 embryos. Mesenchymes were cultured on transwells in the presence of either LIF, NGAL or the ANX fraction and RNA was harvested after 1, 2, 3, 4, 5, and 7 days for RNA extraction. Freshly dissected mesenchymes and mesenchymes cultured in the absence of inducers for 1 and 2 days, respectively, served as controls. Each condition was analyzed in duplicate (biological replicates). Biotinylated cRNA was prepared and hybridized to Affymetrix Rat Genome 230 2.0 Microarrays. Expression values were obtained by robust multichip analysis.