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Aristidis Moustakas - One of the best experts on this subject based on the ideXlab platform.

  • id2 and id3 define the potency of cell proliferation and differentiation responses to Transforming Growth factor β and bone morphogenetic protein
    Molecular and Cellular Biology, 2004
    Co-Authors: Marcin Kowanetz, Ulrich Valcourt, Rosita Bergstrom, Carlhenrik Heldin, Aristidis Moustakas
    Abstract:

    Transforming Growth Factors β (TGF-βs) inhibit Growth of epithelial cells and induce differentiation changes, such as epithelial-mesenchymal transition (EMT). On the other hand, bone morphogenetic proteins (BMPs) weakly affect epithelial cell Growth and do not induce EMT. Smad4 transmits signals from both TGF-β and BMP pathways. Stimulation of Smad4-deficient epithelial cells with TGF-β1 or BMP-7 in the absence or presence of exogenous Smad4, followed by cDNA microarray analysis, revealed 173 mostly Smad4-dependent, TGF-β-, or BMP-responsive genes. Among 25 genes coregulated by both Factors, inhibitors of differentiation Id2 and Id3 showed long-term repression by TGF-β and sustained induction by BMP. The opposing regulation of Id genes is critical for proliferative and differentiation responses. Hence, ectopic Id2 or Id3 expression renders epithelial cells refractory to Growth inhibition and EMT induced by TGF-β, phenocopying the BMP response. Knockdown of endogenous Id2 or Id3 sensitizes epithelial cells to BMP, leading to robust Growth inhibition and induction of transdifferentiation. Thus, Id genes sense Smad signals and create a permissive or refractory nuclear environment that defines decisions of cell fate and proliferation.

  • regulation of actin organisation by tgf beta in h ras transformed fibroblasts
    Journal of Cell Science, 1999
    Co-Authors: Aristidis Moustakas, Christos Stournaras
    Abstract:

    The actin cytoskeleton undergoes architectural changes during the processes of cell transformation and tumourigenesis. Transforming Growth Factors beta arrest cell cycle progression, regulate differentiation and modulate the onset of oncogenesis and tumourigenesis. Here, we investigated the direct role of Transforming Growth factor beta-1 in altering the transformed phenotype and regulating the actin organisation of oncogenic fibroblasts that constitutively or inducibly express the H-ras oncogene. Following Transforming Growth factor beta-1 treatment, these transformed fibroblasts undergo a dramatic morphological alteration that includes a discrete reorganisation of their actin cytoskeleton and focal adhesions. Quantitative biochemical analysis demonstrated that Transforming Growth factor beta-1 potently induced polymerisation of globular to filamentous actin, thus corroborating the morphological analysis. The effect of Transforming Growth factor beta-1 on the cytoskeleton correlates with the ability of this cytokine to suppress anchorage-independent Growth of the transformed fibroblasts. Furthermore, Transforming Growth factor beta-1 upregulates considerably the levels of the RhoB small GTPase and less the RhoA levels. Finally, The beta GTPase inhibitor, C3 exotransferase, blocks the ability of TGF-beta1 to induce cytoskeletal reorganisation. These findings indicate that Transforming Growth factor beta can regulate cell morphology and Growth in a concerted manner possibly via mechanisms that control the actin cytoskeleton.

  • molecular characterization of a type i serine threonine kinase receptor for tgf β and activin in the rat pituitary tumor cell line gh3
    Experimental Cell Research, 1995
    Co-Authors: Toru Takumi, Aristidis Moustakas, Herbert Y Lin, Harvey F Lodish
    Abstract:

    Abstract GH3 pituitary tumor cells have surface receptors for Transforming Growth Factors-β (TGF-βs) anti activins/inhibins. GH3 cell mRNA was screened by a novel reverse transcriptase-polymerase chain reaction technique with primers for receptor serine-threonine kinases. We isolated rat homologs of previously identified clones for type I (ALK-2 and ALK-5) and type II (ActRH, TGF-βRII) activin and TGF-β receptors, together with a novel clone, whose full-length version was isolated from a GH3 cell cDNA library. Named B1, it encodes a 505-amino-acid protein belonging to the family of type I receptor serine/threonine kinases. The kinase domain of B1 exhibits 90% identity to that of the TGF-β type I receptor. B1 mRNA is expressed not only in pituitary cells but also in all other cells and tissues examined. B1 protein can be expressed on the cell surface, but cannot bind ligand unless a type II receptor is also present. When coexpressed with the type II receptors specific for TGF-β or activin, B1 can be efficiently cross-linked to either ligand, suggesting that it can form heteromeric complexes with both type II receptor subunits.

Magali Demoor - One of the best experts on this subject based on the ideXlab platform.

  • improvement of the chondrocyte specific phenotype upon equine bone marrow mesenchymal stem cell differentiation influence of culture time Transforming Growth Factors and type i collagen sirnas on the differentiation index
    International Journal of Molecular Sciences, 2018
    Co-Authors: Thomas Branly, Romain Contentin, Thibaud Jacquel, Frederic Malleingerin, Lélia Bertoni, Mélanie Desancé, Jean-marie Denoix, Sandrine Jacquet, Fabrice Audigié, Magali Demoor
    Abstract:

    Articular cartilage is a tissue characterized by its poor intrinsic capacity for self-repair. This tissue is frequently altered upon trauma or in osteoarthritis (OA), a degenerative disease that is currently incurable. Similar musculoskeletal disorders also affect horses and OA incurs considerable economic loss for the equine sector. In the view to develop new therapies for humans and horses, significant progress in tissue engineering has led to the emergence of new generations of cartilage therapy. Matrix-associated autologous chondrocyte implantation is an advanced 3D cell-based therapy that holds promise for cartilage repair. This study aims to improve the autologous chondrocyte implantation technique by using equine mesenchymal stem cells (MSCs) from bone marrow differentiated into chondrocytes that can be implanted in the chondral lesion. The optimized protocol relies on culture under hypoxia within type I/III collagen sponges. Here, we explored three parameters that influence MSC differentiation: culture times, Growth Factors and RNA interference strategies. Our results suggest first that an increase in culture time from 14 to 28 or 42 days lead to a sharp increase in the expression of chondrocyte markers, notably type II collagen (especially the IIB isoform), along with a concomitant decrease in HtrA1 expression. Nevertheless, the expression of type I collagen also increased with longer culture times. Second, regarding the Growth factor cocktail, TGF-β3 alone showed promising result but the previously tested association of BMP-2 and TGF-β1 better limits the expression of type I collagen. Third, RNA interference targeting Col1a2 as well as Col1a1 mRNA led to a more significant knockdown, compared with a conventional strategy targeting Col1a1 alone. This chondrogenic differentiation strategy showed a strong increase in the Col2a1:Col1a1 mRNA ratio in the chondrocytes derived from equine bone marrow MSCs, this ratio being considered as an index of the functionality of cartilage. These data provide evidence of a more stable chondrocyte phenotype when combining Col1a1 and Col1a2 siRNAs associated to a longer culture time in the presence of BMP-2 and TGF-β1, opening new opportunities for preclinical trials in the horse. In addition, because the horse is an excellent model for human articular cartilage disorders, the equine therapeutic approach developed here can also serve as a preclinical step for human medicine.

H Hoshi - One of the best experts on this subject based on the ideXlab platform.

  • influence of epidermal Growth factor and Transforming Growth factor alpha on in vitro maturation of cumulus cell enclosed bovine oocytes in a defined medium
    Reproduction, 1994
    Co-Authors: K Kobayashi, S Yamashita, H Hoshi
    Abstract:

    This study was carried out to determine the effects of Growth Factors (epidermal Growth factor, Transforming Growth Factors-alpha and -beta 1, basic fibroblast Growth factor, insulin), gonadotrophins (LH, FSH), and fetal bovine serum added to TCM199 medium on cumulus expansion and fertilization during in vitro maturation, and on subsequent embryonic development of bovine cumulus cell-enclosed oocytes. Epidermal Growth factor, Transforming Growth factor-alpha, LH and FSH enhanced cumulus expansion and oocyte fertilizability. No significant effect was achieved with Transforming Growth factor-beta 1 nor with basic fibroblast Growth factor. No additive stimulation on cumulus expansion and oocyte fertilizability was observed when epidermal Growth factor was combined with LH or FSH. The addition of either epidermal Growth factor or Transforming Growth factor-alpha to the maturation medium increased the number of fertilized ova that developed to the blastocyst stage. These results demonstrate the potential use of epidermal Growth factor and Transforming Growth factor-alpha in obtaining high quality mature bovine oocytes for in vitro fertilization.

Annika Enejder - One of the best experts on this subject based on the ideXlab platform.

  • monitoring of lipid storage in caenorhabditis elegans using coherent anti stokes raman scattering cars microscopy
    Proceedings of the National Academy of Sciences of the United States of America, 2007
    Co-Authors: Thomas Hellerer, Claes Axang, Christian Brackmann, Per Hillertz, Marc Pilon, Annika Enejder
    Abstract:

    Better understanding of the fundamental mechanisms behind metabolic diseases requires methods to monitor lipid stores on single-cell level in vivo. We have used Caenorhabditis elegans as a model organism to demonstrate the limitations of fluorescence microscopy for imaging of lipids compared with coherent anti-Stokes Raman scattering (CARS) microscopy, the latter allowing chemically specific and label-free imaging in living organisms. CARS microscopy was used to quantitatively monitor the impact of genetic variations in metabolic pathways on lipid storage in 60 specimens of C. elegans. We found that the feeding-defective mutant pha-3 contained a lipid volume fraction one-third of that found in control worms. In contrast, mutants (daf-2, daf-4 dauer) with deficiencies in the insulin and Transforming Growth Factors (IGF and TGF-β) signaling pathways had lipid volume fractions that were 1.4 and 2 times larger than controls, respectively. This was observed as an accumulation of small-sized lipid droplets in the hypodermal cells, hosting as much as 40% of the total lipid volume in contrast to the 9% for the wild-type larvae. Spectral CARS microscopy measurements indicated that this is accompanied by a shift in the ordering of the lipids from gel to liquid phase. We conclude that the degree of hypodermal lipid storage and the lipid phase can be used as a marker of lipid metabolism shift. This study shows that CARS microscopy has the potential to become a sensitive and important tool for studies of lipid storage mechanisms, improving our understanding of phenomena underlying metabolic disorders.

  • monitoring of lipid storage in caenorhabditis elegans using coherent anti stokes raman scattering cars microscopy
    Proceedings of the National Academy of Sciences of the United States of America, 2007
    Co-Authors: Thomas Hellerer, Claes Axang, Christian Brackmann, Per Hillertz, Marc Pilon, Annika Enejder
    Abstract:

    Better understanding of the fundamental mechanisms behind metabolic diseases requires methods to monitor lipid stores on single-cell level in vivo. We have used Caenorhabditis elegans as a model organism to demonstrate the limitations of fluorescence microscopy for imaging of lipids compared with coherent anti-Stokes Raman scattering (CARS) microscopy, the latter allowing chemically specific and label-free imaging in living organisms. CARS microscopy was used to quantitatively monitor the impact of genetic variations in metabolic pathways on lipid storage in 60 specimens of C. elegans. We found that the feeding-defective mutant pha-3 contained a lipid volume fraction one-third of that found in control worms. In contrast, mutants (daf-2, daf-4 dauer) with deficiencies in the insulin and Transforming Growth Factors (IGF and TGF-beta) signaling pathways had lipid volume fractions that were 1.4 and 2 times larger than controls, respectively. This was observed as an accumulation of small-sized lipid droplets in the hypodermal cells, hosting as much as 40% of the total lipid volume in contrast to the 9% for the wild-type larvae. Spectral CARS microscopy measurements indicated that this is accompanied by a shift in the ordering of the lipids from gel to liquid phase. We conclude that the degree of hypodermal lipid storage and the lipid phase can be used as a marker of lipid metabolism shift. This study shows that CARS microscopy has the potential to become a sensitive and important tool for studies of lipid storage mechanisms, improving our understanding of phenomena underlying metabolic disorders.

Michael T Longaker - One of the best experts on this subject based on the ideXlab platform.