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Proteoglycan Expression
Published by Anonymous on 2007/9/30 (1586 reads)
1: J Anat. 2005 Dec;207(6):727-34.


Instructive niches: environmental instructions that confound NG2 proteoglycan expression and the fate-restriction of CNS progenitors.

Sellers DL, Horner PJ.

Department of Neurosurgery, University of Washington, Seattle, WA 98105, USA. drewfus@u.washington.edu

Cellullar deficits are replenished within the central nervous system (CNS) by progenitors to maintain integrity and recover function after injury. NG2 proteoglycan-expressing progenitors replenish oligodendrocyte populations, but the nature of NG2 proteoglycan may not indicate a restricted population of progenitors. After injury, restorative spatiotemporal cues have the potential ability to regulate divergent fate-choices for NG2 progenitors, and NG2 progenitors are known to produce multiple cell types in vitro. Recent data suggest that NG2 expression is attenuated while protein levels remain high within injurious tissue; thus, NG2 expression is not static but transiently controlled in response to a dynamic interplay of environmental cues. Therefore, NG2 proteoglycan expression could label newly generated cells or be inherited by resident cell populations that produce oligodendrocytes for remyelination, astrocytes that provide trophic support and other cells that contribute to CNS function.

Publication Types:
Review

PMID: 16367800 [PubMed - indexed for MEDLINE]

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2: Pathol Biol (Paris). 2001 May;49(4):364-75.


[Structure and regulation of articular cartilage proteoglycan expression]

[Article in French]

Rédini F.

Laboratoire de biochimie du tissu conjonctif, faculté de médecine, niveau 3, 14032 Caen, France.

Beyond aggrecan, the major proteoglycan present in articular cartilage that confers resistance to compressive load and viscoelasticity to the tissue, other proteoglycan families have been described in cartilage. Among them, decorin, biglycan and fibromodulin which belong to the small leucine-rich proteoglycans family bind to matrix components, specially to collagen fibrils and thus regulate fibrillogenesis in cartilage and matrix integrity. These small proteoglycans can also interact with TGF-beta and modulate its bioavailability and stability. The third family is composed by cell surface proteoglycans as syndecans, glypican-1 and betaglycan. These molecules interact with various components of cell environment (growth factors, proteases, matrix components, etc.) and mediate numerous cell functions. Some modifications of one of these proteoglycan expression occur during degenerative pathologies and may lead to alteration of the functional properties of the tissue as well as variations in growth factor bioavailability. These factors are involved in the attempt of cartilage repair initiated by chondrocytes in the early stages of osteoarthritis.

Publication Types:
English Abstract
Review

PMID: 11428173 [PubMed - indexed for MEDLINE]

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3: Prog Nucleic Acid Res Mol Biol. 1999;62:19-53.


Transcriptional and posttranscriptional regulation of proteoglycan gene expression.

Iozzo RV, Danielson KG.

Department of Pathology, Anatomy, and Cell Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.

Proteoglycans are among the most complex and sophisticated molecules of mammalian systems in terms of their protein and carbohydrate moieties. These macromolecules are in a continuous interplay with each other and the cell surface signal-transducing pathways, some of which are beginning to be elucidated. Because of their domain structure, catalytic potential, and diversity, these molecules appear to be designed for integrating numerous signaling events. For example, some proteoglycans interact with hyaluronan and lectins, thereby linking cell surfaces and distant matrix molecules. Some interact with collagen during the complex process of fibrillogenesis and regulate this biological process fundamental to animal life. Others interact with growth factors and serve as depot available during growth or tissue remodeling. In this review, we center on the most recent developments of proteoglycan biology, focusing primarily on genomic organization and transcriptional and posttranscriptional control. We discuss only those proteoglycans whose gene and promoter elements have been characterized and proved to be functional. When possible, we correlate the effects of growth factors and cytokines on proteoglycan gene expression with the topology of cis-acting elements in their genomic control regions. The analysis leads to a comprehensive critical appraisal of the principles that underlie the regulation of proteoglycan gene expression and to the delineation of common regulatory mechanisms.

Publication Types:
Research Support, U.S. Gov't, P.H.S.
Review

PMID: 9932451 [PubMed - indexed for MEDLINE]

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4: Am J Med Genet. 1996 May 3;63(1):161-6.


Deficient expression of the small proteoglycan decorin in a case of severe/lethal osteogenesis imperfecta.

Dyne KM, Valli M, Forlino A, Mottes M, Kresse H, Cetta G.

Department of Biochemistry, University of Pavia, Italy.

In osteogenesis imperfecta (OI) the effects of mutations in type I collagen genes generally reflect their nature and localization. Unrelated individuals sharing identical mutations present, in general, similar clinical phenotypes. However, in some such cases the clinical phenotype differs. This variable clinical expression could be the result of abnormalities in other connective tissue proteins. Since decorin is a component of connective tissue, binds to type I collagen fibrils and plays a role in matrix assembly, we studied decorin production in skin fibroblasts from OI patients. Cultured fibroblasts from one patient with extremely severe osteogenesis imperfecta (classified as type II/III) who has an alpha 1(I)gly415ser mutation were found to secrete barely detectable amounts of decorin into culture medium. Western blotting using antibodies raised against decorin confirmed the reduction of the decorin core protein and Northern blot analysis showed decorin mRNA levels below the limit of detection. Cells from a patient, with a less severe phenotype, bearing a mutation in the same position of the triple helix (alpha 1(I)gly415) expressed decorin normally. The different clinical phenotypes could be due to the differing genetic backgrounds of the patients so it is tempting to conclude that in our most severely affected patient the absence of decorin aggravates the clinical phenotype.

Publication Types:
Case Reports
Research Support, Non-U.S. Gov't
Review

PMID: 8723103 [PubMed - indexed for MEDLINE]

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5: Pathol Res Pract. 1994 Oct;190(9-10):864-82.


Regulation of proteoglycan expression in fibrotic liver and cultured fat-storing cells.

Gressner AM, Krull N, Bachem MG.

Department of Clinical Chemistry, Philipps University, Marburg, Germany.

Considerable progress has been made in recent years with the molecular dissection of proteoglycans in normal and fibrotic human and rat liver. Proteoglycans constitute a major fraction of extracellular, pericellular and intracellular glycoconjugates. In former times, proteoglycans were classified nearly exclusively on the basis of the composition of their carbohydrate chain (glycosaminoglycan, GAG) attached to the core protein. Accordingly, three main types are discerned in liver, which are in order of decreasing concentrations heparan sulfate (HS, more than 60% of total GAG), dermatan sulfate and chondroitin-4,6-sulfate isomers. Keratan sulfate has not been detected in rat and human liver. Recently, proteoglycans have been characterized by sequencing and cloning of the core proteins to which a number of specific glycosaminoglycan side chains are covalently linked. Accordingly, decorin and biglycan have been identified as major chondroitin sulfate/dermatan sulfate proteoglycans in the extracellular space. In addition, evidence was obtained recently for the expression of aggrecan and lumican, both keratan sulfate bearing proteoglycans, and of syndecan in liver. Using in situ hybridization techniques the temporal and spatial pattern of expression of biglycan, decorin and aggrecan has been assessed. These studies together with Northern blot hybridizations performed with isolated parenchymal and nonparenchymal liver cells confirm that fat-storing cells (Ito cells, perisinusoidal lipocytes), are the most important, principal cellular site of proteoglycan production in diseased liver. The level of expression is regulated by a number of cytokines among which TGF beta, TNF alpha and TGF alpha play significant roles. The effects of these cytokines on proteoglycan expression are dependent on the stage of phenotypic transition of fat storing cells to the activated myofibroblast. Taken together, these data point to the potentially significant role which proteoglycans might fulfil in the regulation of cellular functions and in the maintenance of the supramolecular organization of the extracellular matrix in normal and in diseased liver during the process of fibrogenesis.

Publication Types:
Research Support, Non-U.S. Gov't
Review

PMID: 7899135 [PubMed - indexed for MEDLINE]

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6: EXS. 1994;70:199-214.


Altered proteoglycan gene expression and the tumor stroma.

Iozzo RV, Cohen I.

Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.

Tumor stroma is a specialized form of tissue that is associated with epithelial neoplasms. Recent evidence indicates that significant changes in proteoglycan content occur in the tumor stroma and that these alterations could support tumor progression and invasion as well as tumor growth. Our main hypothesis is that the generation of tumor stroma is under direct control of the neoplastic cells and that, via a feedback loop, altered proteoglycan gene expression would influence the behavior of tumor cells. In this review, we will focus primarily on the work from our laboratory related to the altered expression of chondroitin sulfate proteoglycan and its role in tumor development and progression. The connective tissue stroma of human colon cancer is enriched in chondroitin sulfate and the stromal cell elements, primarily colon fibroblasts and smooth muscle cells, are responsible for this biosynthetic increase. These changes can be reproduced in vitro by using either tumor metabolites or co-cultures of human colon carcinoma cells and colon mesenchymal cells. The levels of decorin, a leucine-rich proteoglycan involved in the regulation of matrix assembly and cell proliferation, are markedly elevated in the stroma of colon carcinoma. These changes correlate with a marked increase in decorin mRNA levels and a concurrent hypomethylation of decorin gene, a DNA alteration associated with enhanced gene expression. Elucidation of decorin gene structure has revealed an unexpected degree of complexity in the 5' untranslated region of the gene with two leader exons that are alternatively spliced to the second coding exon. Furthermore, a transforming growth factor beta (TGF-beta)-negative element is present in the promotor region of decorin gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication Types:
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Review

PMID: 8298247 [PubMed - indexed for MEDLINE]

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7: Experientia. 1993 May 15;49(5):447-55.


Altered proteoglycan gene expression and the tumor stroma.

Iozzo RV, Cohen I.

Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.

Tumor stroma is a specialized form of tissue that is associated with epithelial neoplasms. Recent evidence indicates that significant changes in proteoglycan content occur in the tumor stroma and that these alterations could support tumor progression and invasion as well as tumor growth. Our main hypothesis is that the generation of tumor stroma is under direct control of the neoplastic cells and that, via a feedback loop, altered proteoglycan gene expression would influence the behavior of tumor cells. In this review, we will focus primarily on the work from our laboratory related to the altered expression of chondroitin sulfate proteoglycan and its role in tumor development and progression. The connective tissue stroma of human colon cancer is enriched in chondroitin sulfate and the stromal cell elements, primarily colon fibroblasts and smooth muscle cells, are responsible for this biosynthetic increase. These changes can be reproduced in vitro by using either tumor metabolites or co-cultures of human colon carcinoma cells and colon mesenchymal cells. The levels of decorin, a leucine-rich proteoglycan involved in the regulation of matrix assembly and cell proliferation, are markedly elevated in the stroma of colon carcinoma. These changes correlate with a marked increase in decorin mRNA levels and a concurrent hypomethylation of decorin gene, a DNA alteration associated with enhanced gene expression. Elucidation of decorin gene structure has revealed an unexpected degree of complexity in the 5' untranslated region of the gene with two leader exons that are alternatively spliced to the second coding exon.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication Types:
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Review

PMID: 8500599 [PubMed - indexed for MEDLINE]

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8: Prog Clin Biol Res. 1990;352:71-8.


Cell-surface heparan-sulfate proteoglycan regulates the expression of a membrane-associated neuronal mitogen.

Ratner N.

Dept of Anatomy and Cell Biology, Univ of Cincinnati Medical School, OH.

Publication Types:
Comparative Study
Research Support, Non-U.S. Gov't
Review

PMID: 2144904 [PubMed - indexed for MEDLINE]
 

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