The in Vitro Interaction of Proteoglycans with Type 1 Collagen Is Modulated by Phosphate

Pogány, Gábor; Hernández, Daniel J.; Vogel, Kathryn G.

doi:10.1006/abbi.1994.1365

Cited by 88 publications

(63 citation statements)

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“…The implications of this property in dentinogenesis will be discussed in greater detail below, but it relates to the ability of the core protein to bind collagen at strategic loci and the proposed ability of the GAG chains to regulate inter-fibrillar distances (Scott, 1986). Recent reports have also indicated that biglycan has the capacity to bind collagen molecules (Pogany et al, 1994;Schonherr et al, 1995). In addition, both decorin and biglycan are capable of interacting with soluble growth factors, notably TGFj3, thereby modulating their functional activity (Iozzo and Murdoch, 1996), and also bind to cellsurface receptors influencing cell-cycle progression and the expression of gene products (lozzo, 1997).…”

Section: (B) Small Leucine-rich Proteoglycansmentioning

confidence: 99%

Proteoglycans in Dentinogenesis

Embery

Hall

Waddington

et al. 2001

Critical Reviews in Oral Biology & Medicine

169

158

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The predominant proteoglycans present in predentin and dentin are the chondroitin-sulphate-rich decorin and biglycan and the keratan-sulphate-rich lumican and fibromodulin. These are small, interstitial, leucine-rich proteoglycans which have recently been shown to exist in gradients across the predentin. Antibodies recognizing chondroitin sulphate show a decreasing gradient from the pulpal aspect toward the mineralizing front, the converse being true for keratan sulphate. Antidecorin shows an increase toward the mineralization front. Evidence from biochemical, autoradiographic, and immunohistochemical studies implies that such changes may be brought about by gradients of metalloproteinases. This offers the possibility that the proteoglycans organize the collagen network for receipt of phosphoproteins and phospholipids, the former being evident only at the onset of dentin formation. The suggestion is raised that glycosaminoglycan-depleted leucine-rich protein cores act as sequester points for receipt of phosphoproteins in particular. The rigid, spatially oriented glycosaminoglycan chains on decorin and biglycan are known to bind calcium and may feature directly in mineral initiation.Key words. Dentinogenesis, proteoglycans, phosphoconjugates, metalloproteinases, mineralization.(I) Introduction Jn recent years, there has been a wealth of new information on the group of non-collagenous glycoconjugates present in the extracellular matrix of most connective tissues, termed proteoglycans (PGs). These molecules are deemed to play structural and metabolic functional roles in both the soft and mineralized tissues of the body and are present in a wide variety of non-vertebrate and vertebrate species.Their presence in mineralized tissues, such as bone, has been evident for some time. Although the presence of PGs in predentin and, to a lesser extent, in dentin is well-established, it is only with the advent of contemporary biochemical and immunohistochemical procedures that their speciation, ultrastructural distribution, and possible biological roles in dentinogenesis are beginning to be elucidated.Within the last decade, there have been few reviews specifically addressing the function of PGs in relation to dentinogenesis. Research in this field has borrowed much of its knowledge from connective tissues in general, particularly the work on the aggregating PGs, such as aggrecan, present in cartilage. It The aspect of gradient distribution will be described in detail later and is of major significance, since it offers a functionality for such molecules during the structural transition of the extracellular matrix (ECM) of predentin, leading to the correct spatial assembly of the collagenous-non-coliagenous scaffold as a prelude for mineral deposition. For this reason, the review wili also deal with recent work on the potential of metalioproteinases (MMPs) to bring about such transition and the presence of phosphoprotein in dentin specifically hnked to mineralization. The absence of phosphoprotein from predentin an...

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Section: (B) Small Leucine-rich Proteoglycansmentioning

confidence: 99%

Proteoglycans in Dentinogenesis

Embery

Hall

Waddington

et al. 2001

Critical Reviews in Oral Biology & Medicine

169

158

View full text Add to dashboard Cite

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“…Binding of highly sulfated GAGs to scavenger receptors has been reported, presumably involving an interaction with the positively charged collagen-like domain of SR-As, 29,30 but binding of less sulfated forms, such as HS and CS, has not been examined. Binding of highly sulfated GAGs has been reported to block Ox-LDL catabolism, 62 but less sulfated forms could produce other effects, such as clustering of several SR-As that bind along the same GAG chain or alteration of the conformation of the ligand-binding domain of SR-As.…”

Section: Discussionmentioning

confidence: 99%

Role of Macrophage Glycosaminoglycans in the Cellular Catabolism of Oxidized LDL by Macrophages

Kaplan

Williams

Mandel

et al. 1998

ATVB

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Abstract-Macrophage binding sites for oxidized LDL (Ox-LDL) include class A scavenger receptors (SR-As), the CD-36 molecule, and an additional but hitherto unidentified binding site. Because cell-surface glycosaminoglycans (GAGs) were previously shown to be involved in the cellular uptake of native LDL and lipoprotein(a), several strategies to assess the participation of heparan sulfate (HS) and chondroitin sulfate (CS) in macrophage catabolism of Ox-LDL were used. First, incubation of J-774 A.1 macrophage-like cells with either heparinase or chondroitinase, or with both enzymes together, reduced the binding, uptake, and degradation of 125 I-Ox-LDL by 20% to 45%, in comparison with control nontreated cells, while catabolism of 125 I-labeled acetylated LDL (Ac-LDL) and native LDL were unaffected. Second, the proteoglycan (PG) cellular content was increased by cell enrichment with exogenous GAGs or by using human monocyte-derived macrophages from two patients with Sanfilippo mucopolysaccharidosis, which are characterized by cellular HS accumulation. In these macrophages, cellular uptake of 125 I-Ox-LDL increased, while catabolism of 125 I-Ac-LDL and native LDL were unaffected. Experiments using conditioned media from control, heparinase-digested, or chondroitinase-digested macrophages indicated that neither secreted GAGs nor released digestion products played any role in Ox-LDL catabolism. To evaluate potential interactions between cell-surface GAGs and known receptors for Ox-LDL, we used excess unlabeled Ac-LDL to block SR-As or anti-CD-36 antibodies to block CD-36, and then examined the catabolism of 125 I-Ox-LDL by GAG-enriched or -depleted macrophages. Both excess unlabeled Ac-LDL and anti-CD-36 antibodies reduced 125 I-Ox-LDL catabolism, but only excess unlabeled Ac-LDL completely abolished the increase in 125 I-Ox-LDL catabolism on GAG enrichment of the cells, indicating a cooperation between exogenous GAGs and cell-surface SR-As in the catabolism of OX-LDL. Moreover, the addition of GAGases to macrophages that were preincubated with anti-CD-36 antibodies and excess Ac-LDL further reduced macrophage degradation of Ox-LDL in comparison with cells that were pretreated only with anti-CD-36 antibodies and Ac-LDL, indicating a more complex role for endogenous GAGs. Overall, these studies demonstrate a substantial contribution of macrophage-associated GAGs in the catabolism of Ox-LDL, which is mediated in part by a cooperation between GAGs and cell-surface SR-As. (Arterioscler Thromb Vasc Biol. 1998;18:542-553.) Key Words: proteoglycans Ⅲ oxidized LDL Ⅲ macrophages Ⅲ glycosaminoglycans Ⅲ mucopolysaccharidosis O xidatively modified LDL is likely to play an important contributory role in the development of atherosclerosis. Oxidized epitopes, including oxidized apoB, the major protein of Ox-LDL, have been demonstrated in human lesions. 1,2 Ox-LDL contains many biologically active molecules, such as lysophosphatidylcholine 3,4 and oxidized sterols, 5,6 that substantially alter the metabolism of arterial wall cells. Fu...

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“…Besides dystroglycan, it has been found to bind collagen (Pogany et al, 1994), apolipoprotein E (Klezovitch and Scanu, 2001) and others. Biglycan was found to be upregulated during brain development (Kikuchi et al, 2000a) and at sites of mechanical brain injury for at least up to six months after the lesion (Stichel et al, 1995).…”

Section: Biglycanmentioning

confidence: 99%

Review: Dystroglycan in the Nervous System

Samwald

2007

Nature Precedings

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Dystroglycan is part of a large complex of proteins, the dystrophin-glycoprotein complex, which has been implicated in the pathogenesis of muscular dystrophies for a long time. Besides muscular degeneration many patients manifest symptoms of neurological and cognitive dysfunction. Recent findings suggest that dystroglycan is implicated in brain development, synapse formation and plasticity, nerve-glia interactions and maintenance of the blood-brain barrier. Most research so far has focused on the functions of dystroglycan in muscle and neuromuscular junctions, while its role in the brain and interneuronal synapses has been neglected. This review will give an overview of the biochemistry of dystroglycan, its interaction with other proteins as well as its confirmed and hypothetical functions in the nervous system.

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The in Vitro Interaction of Proteoglycans with Type 1 Collagen Is Modulated by Phosphate

Cited by 88 publications

References 0 publications

Proteoglycans in Dentinogenesis

Proteoglycans in Dentinogenesis

Role of Macrophage Glycosaminoglycans in the Cellular Catabolism of Oxidized LDL by Macrophages

Review: Dystroglycan in the Nervous System

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