Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
Dev Cell ; 9(1): 39-49, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15992539

ABSTRACT

Stretch induces lung embryonic mesenchymal cells to follow a myogenic pathway. Using this system we identified a set of stretch-responsive factors, which we referred to as TIPs (tension-induced/inhibited proteins). TIPs displayed signature motifs characteristic of nuclear receptor coregulators and chromatin remodeling enzymes. A genomic BLAST search suggested that the three TIPs identified were isoforms originated by alternative splicing from a single gene. Functional studies revealed that TIP-1 and TIP-3 were involved in the cell's selection of the myogenic or the adipogenic pathway. TIP-1, induced by stretch, promoted myogenesis, while TIP-3, inhibited by stretch, stimulated adipogenesis. The selection involved TIP-mediated chromatin remodeling via a histone acetylation process and depended on TIP-1 and TIP-3 nuclear receptor binding boxes (NRBs). This study, therefore, suggests a new developmental mechanism linking the presence or absence of tension with divergent differentiation pathways.


Subject(s)
Adipocytes/cytology , Carrier Proteins/physiology , Mechanotransduction, Cellular , Mesenchymal Stem Cells/cytology , Myoblasts/cytology , Nuclear Proteins/metabolism , Acetyltransferases/metabolism , Adipocytes/metabolism , Alternative Splicing , Amino Acid Sequence , Animals , Carrier Proteins/genetics , Cell Differentiation , Cells, Cultured , Chromatin Assembly and Disassembly , Embryo, Mammalian/cytology , Histone Acetyltransferases , Mesenchymal Stem Cells/metabolism , Methyltransferases , Mice , Mice, Inbred ICR , Molecular Sequence Data , Myoblasts/metabolism , Nuclear Proteins/genetics , Protein Isoforms/genetics , Protein Isoforms/metabolism , Stress, Mechanical
2.
Trends Cardiovasc Med ; 13(8): 330-5, 2003 Nov.
Article in English | MEDLINE | ID: mdl-14596949

ABSTRACT

Mechanical force is a critical modulator of smooth muscle (SM) function and gene expression. Very little is known, however, about its contribution to SM myogenesis. This review presents and discusses what has been learned about the role of mechanical force in inducing SM myogenesis and some of the signaling mechanisms involved in this process.


Subject(s)
Muscle Development , Myocytes, Smooth Muscle/physiology , Cell Differentiation , Cell Lineage , Cell Size , Dextrans , Myocytes, Smooth Muscle/metabolism , Pressure , Stress, Mechanical
3.
Am J Respir Cell Mol Biol ; 28(4): 504-11, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12654640

ABSTRACT

Pulmonary lymphangioleiomyomatosis (LAM) is characterized by abnormal smooth muscle-like cell proliferation leading to tissue destruction and cyst formation. We demonstrate that serum response factor (SRF), a critical smooth muscle transcription factor, is overexpressed in LAM cells. To determine whether abnormal SRF levels might have a pathogenic role in LAM, we transfected SRF into mouse lung fibroblasts and performed a cDNA array analysis. High SRF level upregulated the expression of matrix metalloproteinase (MMP)-2 and MMP-14, two MMPs previously shown to be increased in LAM. In addition, SRF down-regulated tissue inhibitor of metalloproteinase (TIMP)-3, one of their inhibitors. TIMP-3 inhibition was further confirmed by reverse transcriptase/polymerase chain reaction, immunoblotting, and immunostaining of human lung fibroblasts transfected with SRF fused to DsRed2 (a red variant of green fluorescent protein). To determine the in vivo significance of our findings, we immunostained 12 LAM cases for TIMP-3. In eight of them, TIMP-3 was ubiquitously present in normal lung parenchyma, but it was absent in LAM lesions. In the remaining cases, including two out of five normal control lungs, the antibody immunoreacted exclusively with elastin, probably due to suboptimal tissue processing. Because timp-3-null mice develop spontaneous emphysema, our findings suggest that SRF-mediated TIMP-3 inhibition might contribute to the tissue damage seen in LAM.


Subject(s)
Gene Expression Regulation, Neoplastic , Lymphangiomyoma/genetics , Serum Response Factor/genetics , Tissue Inhibitor of Metalloproteinase-3/genetics , Animals , Cell Line , Humans , Immunohistochemistry , Lung , Lymphangiomyoma/pathology , Mice , Mice, Inbred Strains , Oligonucleotide Array Sequence Analysis , Plasmids , Recombinant Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Serum Response Factor/metabolism , Transfection
4.
J Clin Invest ; 110(9): 1349-58, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12417574

ABSTRACT

P311, also called PTZ17, was identified by suppressive subtraction hybridization as potentially involved in smooth muscle (SM) myogenesis. P311 is an 8-kDa protein with several PEST-like motifs found in neurons and muscle. P311 transfection into two fibroblast cell lines, NIH 3T3 and C3H10 T1/2, induced phenotypic changes consistent with myofibroblast transformation, including upregulation of SM alpha-actin and SM22, induction of FGF-2, VEGF, PDGF, and PDGF receptors, upregulation of integrins alpha3 and alpha5, and increased proliferation rate. The P311-mediated changes differed, however, from the well-characterized myofibroblast in that P311 inhibited TGF-beta1, TGF-beta receptor 2, and TGF-beta1-activating MMP-2 and MMP-9, with the resultant decrease in collagen 1 and 3 expression. The effect of P311 on collagen was overcome by exogenous TGF-beta1, indicating that the cells were responsive to TGF-beta1 paracrine stimulus. In support of a role for P311 in vivo, immunohistochemical examination of human wounds showed P311 only in myofibroblasts and their activated precursors. To our knowledge, these studies are the first to implicate P311 in myofibroblast transformation, to demonstrate that transformation may occur independently of TGF-beta1, and to suggest that P311 may prevent fibrosis.


Subject(s)
Fibroblasts/physiology , Nerve Tissue Proteins/physiology , Oncogene Proteins/physiology , Transforming Growth Factor beta/physiology , 3T3 Cells , Animals , Cell Differentiation , Collagen/biosynthesis , Humans , Mice , Phenotype , Platelet-Derived Growth Factor/physiology , Tensile Strength , Transforming Growth Factor beta1
5.
J Cell Biol ; 156(5): 893-903, 2002 Mar 04.
Article in English | MEDLINE | ID: mdl-11877460

ABSTRACT

Round embryonic mesenchymal cells have the potential to differentiate into smooth muscle (SM) cells upon spreading/elongation (Yang, Y., K.C. Palmer, N. Relan, C. Diglio, and L. Schuger. 1998. Development. 125:2621-2629; Yang, Y., N.K. Relan, D.A. Przywara, and L. Schuger. 1999. Development. 126:3027-3033; Yang, Y., S. Beqaj, P. Kemp, I. Ariel, and L. Schuger. 2000. J. Clin. Invest. 106:1321-1330). In the developing lung, this process is stimulated by peribronchial accumulation of laminin (LN)-2 (Relan, N.K., Y. Yang, S. Beqaj, J.H. Miner, and L. Schuger. 1999. J. Cell Biol. 147:1341-1350). Here we show that LN-2 stimulates bronchial myogenesis by down-regulating RhoA activity. Immunohistochemistry, immunoblotting, and reverse transcriptase-PCR indicated that RhoA, a small GTPase signaling protein, is abundant in undifferentiated embryonic mesenchymal cells and that its levels decrease along with SM myogenesis. Functional studies using agonists and antagonists of RhoA activation and dominant positive and negative plasmid constructs demonstrated that high RhoA activity was required to maintain the round undifferentiated mesenchymal cell phenotype. This was in part achieved by restricting the localization of the myogenic transcription factor serum response factor (SRF) mostly to the mesenchymal cell cytoplasm. Upon spreading on LN-2 but not on other main components of the extracellular matrix, the activity and level of RhoA decreased rapidly, resulting in translocation of SRF to the nucleus. Both cell elongation and SRF translocation were prevented by overexpression of dominant positive RhoA. Once the cells underwent SM differentiation, up-regulation of RhoA activity induced rather than inhibited SM gene expression. Therefore, our studies suggest a novel mechanism whereby LN-2 and RhoA modulate SM myogenesis.


Subject(s)
Botulinum Toxins , Bronchi/embryology , Laminin/metabolism , Mesoderm/metabolism , Muscle, Smooth/metabolism , Stem Cells/metabolism , rhoA GTP-Binding Protein/metabolism , ADP Ribose Transferases/pharmacology , Animals , Bronchi/cytology , Bronchi/metabolism , Cell Differentiation/drug effects , Cell Differentiation/physiology , Down-Regulation/drug effects , Endothelin-1/pharmacology , Female , Focal Adhesion Kinase 1 , Focal Adhesion Protein-Tyrosine Kinases , Immunohistochemistry , Laminin/pharmacology , Lysophospholipids/pharmacology , Mesoderm/cytology , Mesoderm/drug effects , Mice , Mice, Inbred ICR , Muscle, Smooth/cytology , Muscle, Smooth/drug effects , Phenotype , Protein-Tyrosine Kinases/drug effects , Protein-Tyrosine Kinases/metabolism , RNA, Messenger/metabolism , Stem Cells/cytology , Stem Cells/drug effects , rhoA GTP-Binding Protein/genetics
SELECTION OF CITATIONS
SEARCH DETAIL
...