Loss of muscle mass occurs in a variety of diseases including cancer, chronic heart failure, AIDS, diabetes and renal failure, often aggravating pathological progression. Preventing muscle wasting by promoting muscle growth has been proposed as a possible therapeutic approach. Myostatin is an important negative modulator of muscle growth during myogenesis and myostatin inhibitors are attractive drug targets. However, the role of the myostatin pathway in adulthood and the transcription factors involved in the signaling are unclear. Moreover recent results confirm that other TGF members control muscle mass. Using genetic tools we perturbed this pathway in adult myofibers, in vivo, to characterize the downstream targets and their ability to control muscle mass. Smad2 and Smad3 are the transcription factors downstream of myostatin/TGF and induce an atrophy program which is MuRF1 independent and requires FoxO activity. Furthermore Smad2/3 inhibition promotes muscle hypertrophy independent of satellite cells but partially dependent of mTOR signalling. Thus myostatin and Akt pathways cross-talk at different levels. These findings point to myostatin inhibitors as good drugs to promote muscle growth during rehabilitation especially when they are combined with IGF1-Akt activators.
Smad2 and 3 transcription factors control muscle mass in adulthood.
Specimen part, Time
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No associated publication
Specimen part
View SamplesThe first site exhibiting hematopoietic activity in mammalian development is the yolk sac blood island, which originates from the hemangioblast. Here we performed differentiation assays, as well as genome-wide molecular and functional studies in BL-CFCs to gain insight into the function of the essential Ldb1 factor in early primitive hematopoietic development. We show that the previously reported lack of yolk sac hematopoiesis and vascular development in Ldb1-/- mouse result from a decreased number of hemangioblasts and a block in their ability to differentiate into erythroid and endothelial progenitor cells. Transcriptome analysis and correlation with the genome wide binding pattern of Ldb1 in hemangioblasts revealed a number of direct target genes and pathways misregulated in the absence of Ldb1. The regulation of essential developmental factors by Ldb1 defines it as an upstream transcriptional regulator of hematopoietic/endothelial development. We show the complex interplay that exists between transcription factors and signaling pathways during the very early stages of hematopoietic/endothelial development and the specific signalling occurring in hemangioblasts in contrast to more advanced hematopoietic developmental stages. Finally, by revealing novel genes and pathways, not previously associated with early development, our study provides novel candidate targets to manipulate the differentiation of hematopoietic and/or endothelial cells.
Genome-wide analysis shows that Ldb1 controls essential hematopoietic genes/pathways in mouse early development and reveals novel players in hematopoiesis.
Specimen part
View SamplesOocyte maturation is accompanied by a transition from mRNA stability to instability. We investigated the role of DCP1A and DCP2, proteins responsible for mRNA decapping, in mRNA destabilization during mouse oocyte maturation.
Maternally recruited DCP1A and DCP2 contribute to messenger RNA degradation during oocyte maturation and genome activation in mouse.
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View SamplesIn order to study the consequences of the loss of Icsbp expression in hematopoiesis Granulocyte-Monocyte Progenitors from bone marrow were isolated from Icsbp wild type and deficient mice by flow cytometry. Global gene expression was performed using Affymetrix gene chip technology.
No associated publication
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View SamplesSalivary glands are essential structures that secrete saliva to the oral cavity and maintain oral health. Development of salivary glands in mice and humans is controlled by mesenchymally expressed fibroblast growth factor-10 (FGF10). Using single cell RNA-seq atlas of the salivary gland and a tamoxifen inducible Fgf10CreERT2:R26-tdTomato mouse we show that FGF10pos cells are exclusively mesenchymal until postnatal day 5 (P5), but after P7, there is a switch in expression and only epithelial FGF10pos cells are observed after P15. Further RNAseq analysis of sorted mesenchymal and epithelial FGF10pos cells shows that the epithelial FGF10pos populations express the hallmark of ancient ionocyte signature Foxi1, Foxi2, Ascl3 and the cystic fibrosis transmembrane conductance regulator (Cftr). We propose that epithelial FGF10pos cells are specialized salivary gland ionocytes that are important for the ionic modification of saliva. In addition, they maintain FGF10-dependent glands homeostasis via communication with FGFR2b-expressing epithelial progenitor and myoepithelial cells Overall design: Comparison of Fgf10+ expressing cell mRNA profiles from submandibular glands of 7 day old pups and 60 days old mice in duplicate
A mesenchymal to epithelial switch in Fgf10 expression specifies an evolutionary-conserved population of ionocytes in salivary glands.
Specimen part, Genotype, Subject
View SamplesWe aimed to define epithelial-specific genes in the kidney. In the developing mouse kidney at E12.5 epithelial cells are restricted to the ureteric bud, while mesenchymal cells surrounding the ureteric bud are non-epithelial. The mouse renal epithelial cell line mIMCD-3 was used to represent kidney epithelia in vitro. Gene expression was analyzed using Affymetrix microarrays in ureteric bud stalks, ureteric bud tips, and mIMCD-3 cells and compared to metanephric mesenchyme.
The transcription factor grainyhead-like 2 regulates the molecular composition of the epithelial apical junctional complex.
Specimen part, Cell line
View SamplesAims: We investigate sex differences and the role of oestrogen receptor beta (ERbeta) in a mouse model of pressure overload-induced myocardial hypertrophy. Methods and results: We performed transverse aortic constriction (TAC) or sham surgery in male and female wild-type (WT) and ERbeta knockout (ERbeta-/-) C57Bl6 mice. All mice were characterised by echocardiography and haemodynamic measurements and were sacrificed nine weeks after surgery. Left ventricular (LV) samples were analysed by microarray profiling, real-time RT-PCR and histology. After nine weeks, WT males showed more hypertrophy and heart failure signs than WT females. Notably, WT females developed a concentric form of hypertrophy, while males developed eccentric hypertrophy. These sex differences were abolished in ERbeta-/- mice. ERbeta deletion augmented the TAC-induced increase in cardiomyocyte diameter in both sexes. Gene expression profiling revealed that male WT hearts had a stronger induction of matrix-related genes and a stronger repression of mitochondrial genes than female hearts. ERbeta-/- mice exhibited a different transcriptome. Induction of pro-apoptotic genes after TAC occurred in ERbeta-/- mice of both sexes with a stronger expression in ERbeta-/- males. Histological analysis revealed, that cardiac fibrosis was more pronounced in male WT TAC than in female mice. This was abolished in ERbeta-/- mice. Apoptosis was significantly induced in both sexes of ERbeta-/- TAC mice, but it was most prominent in males. Conclusion: Female sex offers protection against ventricular chamber dilation in the TAC model. Both the female sex and ERbeta attenuate the development of fibrosis and apoptosis; thus slowing the progression to heart failure.
Female sex and estrogen receptor-beta attenuate cardiac remodeling and apoptosis in pressure overload.
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
An integrated approach to dissecting oncogene addiction implicates a Myb-coordinated self-renewal program as essential for leukemia maintenance.
Specimen part, Treatment
View SamplesTo explore oncogene addiction programs in a genetically defined leukemia context we developed an AML mouse model driven by a conditional MLL-AF9 allele together with oncogenic Ras, which enabled us to examine the consequences of MLL-AF9 inhibition in established disease. In order to produce a tightly regulated system that was easy to monitor, we constructed two retroviral vectors containing dsRed-linked MLL-AF9 under control of a tetracycline response element promoter, and KrasG12D or NrasG12D linked to the Tet-off tet-transactivator, which activates TRE expression in a doxycycline repressible manner. Leukemias were generated by retroviral cotransduction of both vectors into hematopoietic stem and progenitor cells, which were transplanted into syngeneic mice. Cells harboring both constructs induced aggressive myelomonocytic leukemia. Five independent primary leukemia cell lines were established from bone marrow of terminal mice. Treatment of these lines with doxycycline rapidly turned off MLL-AF9 expression, and induced terminal myeloid differentiation and complete disease remission in vivo.
An integrated approach to dissecting oncogene addiction implicates a Myb-coordinated self-renewal program as essential for leukemia maintenance.
Specimen part, Treatment
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