MiR-34a is dispensable for normal development but its loss accelerates medulloblastoma formation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Marion Horsch
PROVIDER: E-GEOD-40511 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Arterial injury or occlusive arterial disease may stimulate healing responses, which when overexuberant, leads to restenosis of the injured vessel. This response is influenced by specific integrin signalling in vascular smooth muscle cells (VSMCs). Microfibril-associated protein 4 (MFAP4) colocates in blood vessels with elastic fibers. MFAP4 contains an N-terminal RGD-motiv, which is a potential integrin binding site. The role for MFAP4 in vascularproliferative disease is so far unknown and the subject for these investigations. Here we show that MFAP4 is expressed and secreted by VSMCs and binds elastin and collagen. MFAP4 mediated adhesion, and migration, and proliferation of VSMCs in an integrin M-NM-1VM-NM-23/5 dependent manner and the effects were inhibited by MFAP4 blocking antibodies. MFAP4 deficient mutant mice were generated and appeared with a normal cardiophysiological phenotype. When challenged by carotid artery ligation, the MFAP4 deficient mice had delayed neointimal formation and the compensatory outward remodeling of the vessel diameter and thus the vessel lumen was reduced. MFAP4 expression appeared unaffected by the induced pathology. HUMANE DATA This new MFAP4 mediated molecular mechanism for regulation of integrin M-NM-1VM-NM-23/5 signalling may have therapeutic implications in diseases where VSMC migration and proliferation are involved in the pathogenesis. For genome-wide expression analysis total RNA from heart of four male MFAP4-/- and four control mice was isolated using RNeasy Midi kit (Qiagen, Hilden, Germany). The cDNA microarrays were generated, hybridized and analysed as described (Horsch et al 2009). Two chip hybridizations were performed with total RNA for each individual mutant mouse against a reference RNA pool of the same organ.
2013-04-01 | E-GEOD-40480 | biostudies-arrayexpress
Project description:The important function of Eya (eyes absent) in eye development of D.melanogaster is well known, the function of its mammalian orthologs Eya1-4 is only partially understood. Yet, no phenotype for Eya2 and Eya3 in humans or mouse have been described. In our study we analysed new Eya-deficient mouse model generated by insertional mutagenesis. Expression analysis of Eya3 by in-situ hybridizations and M-NM-2-Gal-staining revealed a broad expression of the gene throughout development, e.g. in brain, eyes, branchial arches, somites and limbs. This diverse expression pattern suggests pleiotropic effects of Eya3 in mammalian organisms. In contrast to D. melanogaster, a close examination of the eye by various methods did not show any obvious ocular defects in mutant animals. A broad phenotypical characterization of homozygous mutants displayed decreased body weight and body length. Additionally, behavioral changes as a educed forward locomotor activity and altered exploratory behaviour were identified. A significant reduction of forelimb grip strength and an impairment of cardiac processes in Eya3-/- mice suggest a role for Eya3 in muscle development and heart function. Our results implicate that Eya3 plays various roles outside the eye with effects particularly on heart and muscle function in the mouse. Keywords: Eya3-deficient mice, cDNA microarrays, brain, heart, muscle analysis of 4 Eya3 mutant mice versus a pool of 5 wildtype animals; brain, heart, and muscle; 8 hybridisations for each tissue: two technical replicates for each mutant animal including one dye-swap experiments
2008-12-17 | E-GEOD-9999 | biostudies-arrayexpress
Project description:In a variety of organisms, including mammals, caloric restriction improves metabolic status and lowers the incidence of chronic-degenerative diseases, ultimately leading to increased lifespan. Here we show that knockout mice for Eps8, a regulator of actin dynamics, display reduced bodyweight, partial resistance to age- or diet-induced obesity, and overall improved metabolic status. We present evidence that these phenotypes, which are associated to increased lifespan in the Eps8 null mice, are due to caloric restriction. This, in turn, is caused by reduced intestinal fat absorption, due to altered morphogenesis of microvilli in intestinal enterocytes. In the nematode, genetic removal of Eps8, causes a microvillar phenotype, indistinguishable from that observed in mice, which leads to early larval lethality. By exploiting the nematode model system, we demonstrate here that the actin bundling activity of Eps8 is indispensable for viability and proper intestinal morphogenesis. This result links a precise molecular function of Eps8 to proper microvillar morphogenesis, and therefore to the phenotype of Eps8-null mice. Our results implicate actin dynamics in individual variations in bodyweight, metabolic status and longevity. cDNA expression profiling of liver of 4 mutant EPS8 -/- animals versus pool of 4 wt animals. 8 hybridisation including 4 dye swap experiments
2010-03-09 | E-GEOD-14454 | biostudies-arrayexpress
Project description:BACKGROUND: The Notch signaling pathway is an evolutionary conserved signal transduction pathway involved in embryonic patterning and regulation of cell fates during development and self-renewal. Recent studies have demonstrated that this pathway is integral to a complex system of interactions, involving as well other signal transduction pathways, and implicated in distinct human diseases. Delta-like 1 (Dll1) is one of the known ligands of the Notch receptors. The role of the Notch ligands is less well understood. Loss-of-function of Dll1 leads to embryonic lethality, but reduction of Delta-like 1 protein levels has not been studied in adult stage. METHODOLOGY/PRINCIPAL FINDINGS: Here we present the haploinsufficient phenotype of Dll1 and a missense mutant Dll1 allele (Dll1(C413Y)). Haploinsufficiency leads to a complex phenotype with several biological processes altered. These alterations reveal the importance of Dll1 mainly in metabolism, energy balance and in immunology. The animals are smaller, lighter, with altered fat to lean ratio and have increased blood pressure and a slight bradycardia. The animals have reduced cholesterol and triglyceride levels in blood. At the immunological level a subtle phenotype is observed due to the effect and fine-tuning of the signaling network at the different levels of differentiation, proliferation and function of lymphocytes. Moreover, the importance of the proteolytic regulation of the Notch signaling network emphasized. CONCLUSIONS/SIGNIFICANCE: In conclusion, slight alterations in one player of Notch signaling alter the entire organism, emphasizing the fine-tuning character of this pathway in a high number of processes. Four organs (liver, spleen, thymus, brain) of the Dll1 mutant mouse line analysed by cDNA microarray technology. Experiments include four biological replicates for reference (wildtype) and mutant animals. Two technical replicates for each mutant mouse were performed. As reference pooled RNA of the same organ was used. 50% of the chip hybridisations are dye sway experiments.
2009-03-01 | E-GEOD-12954 | biostudies-arrayexpress
Project description:The evolutionarily conserved Delta-Notch cell-cell signal-transduction pathway regulates the determination of various cell fates, which are important for the morphogenesis and development of numerous organs and tissues in many vertebrates and invertebrates. The Dll1 gene was mutated by homologous recombination in embryonic stem cells such that amino acids 2-116 were replaced with an in-frame fusion of the lacZ gene of E.coli. Mouse Dll1 genomic clones were isolated from a strain 129/SvPas library. The replacement vector was constructed by inserting a 4 kb ClaI/XhoI fragment, which encodes a part of the beta-galactosidase gene followed by the PGK-neo cassette, and a 2.6 kb XhoI/EcoRI fragment as the 3M-bM-^@M-^Y homologous region of the replacement vector into pKS+. This vector was linearized with SalI and ClaI, and a 4.1 kb SalI/NcoI as the 5M-bM-^@M-^Y homologous region plus an NcoI/ClaI fragment (800 bp) completing the b-galactosidase gene, were inserted, resulting in the complete replacement vector. This vector was linearized with SalI and electroporated in R1 embryonic stem cells. Correctly targeted clones were identified and verified by Southern blot analysis using external probes from the 3M-bM-^@M-^Y and 5M-bM-^@M-^Y region of the targeted area, and were injected into C57BL/6J embryo to obtain germline transmission. The two analysed Dll1 mutant mouse lines carry the same mutation but are on different genetic background: 1. Heterozygous F1-animals were backcrossed several times to the 129SV/J wild type; 2. Heterozygous F1-animals were outcrossed 11 generation to C3HeB/FeJ wild type Four organs (liver, spleen, thymus, brain) of two Dll1 mutant mouse lines on different genetic background carrying the same mutation were analysed by cDNA microarray technology. Experiment include 4-5 biological replicates for reference (wildtype) and mutant animals. Up to 4 technical replicates for each mutant mouse were performed. As reference pooled RNA was used. 50% of the chip hybridisations are dye sway experiments.
2009-01-01 | E-GEOD-11867 | biostudies-arrayexpress
Project description:Previous studies have evaluated the role of miRNAs in the initiation and progression of cancer. MiR-34a was found to be downregulated in several tumors, including medulloblastoma. We here analysed the function of miR-34a in vivo by targeted transgenesis to generate mice with constitutive deletion of the miR-34a gene, which resulted in the absence of mir-34a in all analysed tissues. Nevertheless, these mice were viable and fertile. A comprehensive standardized phenotypic analysis including more than 300 single parameters performed by the German Mouse Clinic revealed no apparent phenotype. Analysis of miR-34a expression in human medulloblastomas and medulloblastoma cell lines revealed significant downregulation as compared to human cerebellum. Re-expression of mir-34a in human medulloblastoma cells in vitro reduced cell viability, cell proliferation and induced apoptosis. Among the targets downregulated by miR-34a in human medulloblastoma cells were NMYC and SIRT1. Activation of the Shh pathway by targeted overexpression of SmoA1 causes medulloblastoma in mice, which is dependent on the presence and upregulation of NMYC. Analysis of miR-34a in ND2:SmoA1-derived medulloblastomas revealed significant suppression of miR-34a compared to normal cerebellum. Crossbreeding these mice with miR-34a knockout mice significantly accelerated medulloblastoma growth in mice deficient for miR-34a. Interestingly, NMYC and SIRT1 were highly expressed in medulloblastomas derived from these mice. We here demonstrate that miR-34a is dispensable for normal development, but that its loss accelerates medulloblastoma. Strategies aiming to re-express miR-34a in tumors could therefore represent an efficient therapy option.
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2011-01-01 | E-GEOD-20561 | biostudies-arrayexpress
Project description:V-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ERBB2; synonyms HER2, NEU) encodes a transmembrane glycoprotein with tyrosine kinase-specific activity that acts as a major switch in different signal-transduction processes. ERBB2 amplification and overexpression have been found in a number of human cancers, including breast, ovary and kidney carcinoma. Our aim was to detect ERBB2-regulated target genes regulated in Erbb2 transfected murine fibroblast cells after tetracycline treatment to stop the overexpression of ERBB2. Changes in gene expression patterns in these cells after the switch-off of Erbb2 expression was analysed after 8 different periods of time after the treatement (1h-7d). Identification of co-regulated genes and in cluster analysis were performed. Keywords: Erbb2, cDNA microarrays, murine fibroblasts, gene expression levels of 8 different measurements after tetracycline treatment (1h, 2h, 4h, 12h, 24h, 3d, 5d and 7d) were compared to the non-treated NIH3T3 cell line. As control two different untreated NIH3T3 cell line were ananysed. For all comparisons 4 experiments have been performed including 2 dye swaps.
2009-09-01 | E-GEOD-8373 | biostudies-arrayexpress
Project description:Col1a1 is located on mouse distal chromosome 11 (Celera 94607393-94622990bp; 15kb) and encodes type I procollagen that associates stoichiometrically with col1a2 in forming secreted type I mature collagen that self-assembles into a supramolecular fibrillar structure consisting of a protein family. Type I collagens are predominantly enriched in bone, cartilage, skin, tendons, and eye (i.e. in major fibrous tissues) making up the main extracellular matrix (ECM) component for support and scaffolding purposes. Col1a1 is known to be expressed in the embryo (E9.5; Northern dot blot), perioptic mesenchyme (E11), cornea (E11), skeleton (E14.5), brain meninges (E14.5), and cartilage (E14.5) at relatively early stages. Most evidence of type I collagen function is coupled to the latter stages of skeletal development, thus bypassing the major events of axis formation, tissue differentiation, and mesenchlymal-epithial interactions, for example, that are more symbolic of morphogens and growth factors. Members of the integrin cell surface receptor family of molecules mediate cell adhesion to ECM proteins such as collagen (mainly to type IV basement membrane collagen that forms into a polygonal meshwork), fibronectin, and laminin implicated in wound healing and inflammatory responses (e.g. Crohn disease, ulcerative colitis) in connective tissues. There is some evidence for protein-protein interactions between leukocyte-associated integrins and the interstitial matrix in promoting the migration and/or activation of extravasated leukocytes (e.g., T cells and monocytes) within the perivascular compartment, an ECM-rich environment. This region is surmised to be an important location where certain human leukocytes undergo differentiation (e.g. monocytes) and activation (neutrophils, monocytes, lymphocytes) upon extravascular migration. The von Willebrand factor (vWF), type C motif is found in various plasma proteins like complement factors, the integrins, collagen types, and other extracellular proteins. Thus, the majority of vWF-containing proteins are extracellular and a common feature appears to be involvement in multi protein complexes participating in numerous biological events (e.g. cell adhesion, migration, homing, pattern formation, and signal transduction). Three organs (lung, heart and bone) of 5 AGA002 mutant mice (age 2x 10 days and 3x 11 days) were analysed by cDNA microarray technology. As reference five mice, 11 days old were used 50% of the chip hybridisations are dye swap experiments.
2010-06-01 | E-GEOD-12847 | biostudies-arrayexpress
Project description:ADARs, short for adenosine deaminases acting on RNA, were first found by their characteristic activity of deaminating up to 50% of all adenosines in double-stranded RNA in vitro. C. elegans has two ADARs, only one is found in the fly, and mammals express three ADARs. Importantly, the spectrum of physiological roles of these enzymes in the different organisms remains largely unknown. ADARs are ~750-1150 amino acids in size, feature 2-3 N-terminal double-stranded RNA binding motifs, an enzymatic domain related to that of prokaryotic cytidine deaminases, and a ~190 residue extended C-terminal domain of unknown function. The mammalian ADARs are detectable in many if not all tissues, with relatively prominent expression in the central nervous system, predicting tissue- or cell type-specific tasks for the mammalian ADARs. Studies over the last decade collectively indicated that one function of ADARs is the editing of nuclear transcripts to introduce select amino acid substitutions in proteins. Arguably the best-studied example for this type of RNA editing (‘A-to-I editing’) in the mammal is performed by ADAR2 and occurs in primary transcripts for the GluA2 subunit (also known as GluR-B or GluR2 subunit) of AMPA receptors mediating fast excitatory neurotransmission. A particular glutamine codon (CAG) in the exonic sequence for the inner lining of the glutamate-activated AMPA receptor is converted by deamination of the central adenosine into an unusual arginine codon (CIG; the resultant inosine is seen as guanosine by the protein translation machinery). This substitution of the gene-encoded glutamine codon by the edited arginine codon is found in nearly 100% of all GluA2 cDNA derived from brain mRNA. RNA editing in this instance ensures that GluA2-containing AMPA receptors become impermeable to Ca2+. In addition to switching a key functional determinant in GluA2 to nearly 100%, ADAR2 has been implicated in generating numerous amino acid substitutions at lower levels in various mammalian neurotransmitter receptors and voltage-gated ion channels, primarily but not exclusively of nervous tissue. Most of these substitutions elicit distinct functional consequences, which led to the notion that site-selective RNA editing by ADAR2 may ensure the functional fine-tuning of the affected transmembrane proteins. Such fine-tuning should reflect the expansion of the protein sequence directed by the respective gene into sequence subpopulations, each differing in particular functional aspects, such as transmitter efficacy, desensitization, or voltage threshold. If this notion is correct, ADAR2 knockout should elicit phenotypes, which might range from subtle to severe, depending on the physiological role(s) of the ADAR2 targets in different tissues. ADAR2 knockout mice, however, die soon after birth from severe epileptic seizures, a consequence of the changed ion conductance properties of AMPA receptors containing unedited GluA2. Fortunately, mice lacking ADAR2 are robust and have normal life span if they carry GluA2 alleles genetically altered to contain the particular arginine codon for a Ca2+ impermeable ion channel pore of AMPA receptors, thus rescinding the need for ADAR2-mediated GluA2 transcript editing. These mice are thus eminently suitable to study the phenotypic consequences of failure to edit all ADAR2 targets excepting GluA2. We therefore tested cohorts of ADAR2-/-/GluA2(R)/(R) mice in 16 well-established paradigms for central and peripheral phenotypic abnormalities. We report that we found few differences to control mice (GluA2(R)/(R)) and hence, the lack of ADAR2 appears not to affect most of the physiological functions tested. Brain of four mutant animals of ADAR-/-/GluR-BR/R versus a pool of four reference (wildtype) mice; two technical replicates for each mutant mouse including a dye swap experiment - in total 8 chip hybridisations
2010-11-01 | E-GEOD-15383 | biostudies-arrayexpress