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Collagen Function
Published by Anonymous on 2007/9/24 (3617 reads)
1: ScientificWorldJournal. 2007 Mar 30;7:404-20.


Collagen structure of tendon relates to function.

Franchi M, Trirè A, Quaranta M, Orsini E, Ottani V.

Department of Human Anatomical Sciences and Physiopathology of Locomotor Apparatus, University of Bologna, Bologna, Italy. marco.franchi3@unibo.it

A tendon is a tough band of fibrous connective tissue that connects muscle to bone, designed to transmit forces and withstand tension during muscle contraction. Tendon may be surrounded by different structures: 1) fibrous sheaths or retinaculae; 2) reflection pulleys; 3) synovial sheaths; 4) peritendon sheaths; 5) tendon bursae. Tendons contain a) few cells, mostly represented by tenoblasts along with endothelial cells and some chondrocytes; b) proteoglycans (PGs), mainly decorin and hyaluronan, and c) collagen, mostly type I. Tendon is a good example of a high ordered extracellular matrix in which collagen molecules assemble into filamentous collagen fibrils (formed by microfibrils) which aggregate to form collagen fibers, the main structural components. It represents a multihierarchical structure as it contains collagen molecules arranged in fibrils then grouped in fibril bundles, fascicles and fiber bundles that are almost parallel to the long axis of the tendon, named as primary, secondary and tertiary bundles. Collagen fibrils in tendons show prevalently large diameter, a D-period of about 67 nm and appear built of collagen molecules lying at a slight angle (< 5 degrees). Under polarized light microscopy the collagen fiber bundles appear crimped with alternative dark and light transverse bands. In recent studies tendon crimps observed via SEM and TEM show that the single collagen fibrils suddenly changing their direction contain knots. These knots of collagen fibrils inside each tendon crimp have been termed "fibrillar crimps", and even if they show different aspects they all may fulfil the same functional role. As integral component of musculoskeletal system, the tendon acts to transmit muscle forces to the skeletal system. There is no complete understanding of the mechanisms in transmitting/absorbing tensional forces within the tendon; however it seems likely that a flattening of tendon crimps may occur at a first stage of tendon stretching. Increasing stretching, other transmission mechanisms such as an interfibrillar coupling via PGs linkages and a molecular gliding within the fibrils structure may be involved.

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

PMID: 17450305 [PubMed - indexed for MEDLINE]

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2: Clin Calcium. 2006 Jun;16(6):940-47.


[Bone and bone related biochemical examinations. Bone and collagen related metabolites. Regulatory mechanisms of osteoclast differentiation and function]

[Article in Japanese]

Takahashi N.

Matsumoto Dental University, Division of Hard Tissue Research, Institute for Oral Science.

Osteoclast differentiation is tightly regulated by osteoblasts. Osteoblasts express two cytokines, macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-kappaB ligand (RANKL), essential for osteoclast differentiation. Osteoclast precursors firstly differentiate into mononuclear osteoclasts in response to M-CSF and RANKL. Nuclear factor of activated T cells 1 (NFATc1) is a transcription factor, which is involved in the determination of osteoclast differentiation. The mononuclear osteoclast then fuses each other to form the multinucleated cell. Dendritic cell-specific transmembrane protein (DC-STAMP) plays an important role in the fusion of mononuclear osteoclasts. Osteoclasts recognize bone and form ruffled borders and clear zones on the bone surface (polarization). Polarizing osteoclasts construct active vascular transportation systems to resorb bone efficiently. RANK-TRAF6 (TNF receptor-associated factor 6) -mediated signals key roles in both osteoclast differentiation and function. In this article, I will review the recent findings on osteoclast differentiation and function.

Publication Types:
English Abstract
Review

PMID: 16751689 [PubMed - indexed for MEDLINE]

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3: Adv Protein Chem. 2005;70:341-74.


Collagen fibril form and function.

Wess TJ.

Structural Biophysics Division, School of Optometry and Vision Science, Cardiff University, Cardiff, Wales, United Kingdom.

The majority of collagen in the extracellular matrix is found in a fibrillar form, with long slender filaments each displaying a characteristic approximately 67?nm D-repeat. Here they provide the stiff resilient part of many tissues, where the inherent strength of the collagen triple helix is translated through a number of hierarchical levels to endow that tissue with its specific mechanical properties. A number of collagen types have important structural roles, either comprising the core of the fibril or decorating the fibril surface to give enhanced functionality. The architecture of subfibrillar and suprafibrillar structures (such as microfibrils), lateral crystalline and liquid crystal ordering, interfibrillar interactions, and fibril bundles is described. The fibril surface is recognized as an area that contains a number of intimate interactions between different collagen types and other molecular species, especially the proteoglycans. The interplay between molecular forms at the fibril surface is discussed in terms of their contribution to the regulation of fibril diameter and their role in interfibrillar interactions.

Publication Types:
Review

PMID: 15837520 [PubMed - indexed for MEDLINE]

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4: J Musculoskelet Neuronal Interact. 2005 Mar;5(1):5-21.


Development of tendon structure and function: regulation of collagen fibrillogenesis.

Zhang G, Young BB, Ezura Y, Favata M, Soslowsky LJ, Chakravarti S, Birk DE.

Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.

In the tendon, the development of mature mechanical properties is dependent on the assembly of a tendon-specific extracellular matrix. This matrix is synthesized by the tendon fibroblasts and composed of collagen fibrils organized as fibers, as well as fibril-associated collagenous and non-collagenous proteins. All of these components are integrated, during development and growth, to form a functional tissue. During tendon development, collagen fibrillogenesis and matrix assembly progress through multiple steps where each step is regulated independently, culminating in a structurally and functionally mature tissue. Collagen fibrillogenesis occurs in a series of extracellular compartments where fibril intermediates are assembled and mature fibrils grow through a process of post-depositional fusion of the intermediates. Linear and lateral fibril growth occurs after the immature fibril intermediates are incorporated into fibers. The processes are regulated by interactions of extracellular macromolecules with the fibrils. Interactions with quantitatively minor fibrillar collagens, fibril-associated collagens and proteoglycans influence different steps in fibrillogenesis and the extracellular microdomains provide a mechanism for the tendon fibroblasts to regulate these extracellular interactions.

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

PMID: 15788867 [PubMed - indexed for MEDLINE]

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5: Cancer Treat Res. 2004;118:101-24.


Type I collagen-mediated changes in gene expression and function of prostate cancer cells.

Kiefer J, Alexander A, Farach-Carson MC.

Department of Biological Sciences, University of Delaware, USA.

In this study, cDNA microarrays were used to characterize gene expression changes elicited in prostate cancer cells by plating them on type I collagen. The results clearly reveal changes in the expression of genes associated with cellular signaling, cellular metabolism, gene transcription and gene translation which are indicative of cells that are actively proliferating. Together these results suggest that these changes in the gene expression profiles mediated by type I collagen may influence the proliferative capacity of prostate cancer cells in the bone microenvironment and facilitate development of prostate cancer bone metastases. Additionally, the microarray approach provides an invaluable tool to determine and track changes in gene expression in numerous disease states including prostate cancer. This technology is certain to facilitate discovery of new therapeutic gene targets.

Publication Types:
Comparative Study
Review

PMID: 15043190 [PubMed - indexed for MEDLINE]

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6: Semin Cell Dev Biol. 2003 Oct;14(5):275-82.


HSP47 as a collagen-specific molecular chaperone: function and expression in normal mouse development.

Nagata K.

Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8397, Japan. nagata@frontier.kyoto-u.ac.jp

A large family of molecular chaperones can be divided into two major groups: general chaperone and substrate-specific chaperone. HSP47 is a collagen-specific molecular chaperone residing in the endoplasmic reticulum (ER). Recent studies revealed that HSP47 is essential molecular chaperone for mouse development and is essential for collagen molecular maturation in the ER. In the absence of HSP47, collagen microfibril formation and basement membrane formation are impaired in mouse embryos because the failure in the molecular maturation of types I and IV collagens, respectively. The tissue-specific expression of HSP47 is always correlated with that of various types of collagens and closely related with the collagen-related diseases including fibrosis in various organs. The importance of HSP47 in the therapeutic strategy for fibrotic diseases as well as for a marker of collagen-related autoimmune diseases will also be discussed.

Publication Types:
Review

PMID: 14986857 [PubMed - indexed for MEDLINE]

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7: IUBMB Life. 2002 Feb;53(2):77-84.


Structure and function of collagen-derived endostatin inhibitors of angiogenesis.

Sasaki T, Hohenester E, Timpl R.

Max-Planck-Institut für Biochemie, Martinsried, Germany.

Endostatins are inhibitors of endothelial cell migration and angiogenesis and have been shown to reduce tumor growth in animal models. They are derived from the nontriplehelical C-terminal NC1 domains of collagens XV and XVIII, which are released proteolytically in trimeric form and further converted to monomeric endostatins of about 20 kDa. Both endostatin isoforms share a compact globular fold, but differ in certain binding properties for proteins and cells, as well as in tissue distribution. Differences in activity were found between NC1 domains and endostatins and are related to the oligomerization state. Endostatin effects are not restricted to endothelial cells, but also control renal epithelial cells and neuronal guidance in C. elegans. Cellular receptors are still insufficiently characterized and include for endostatin-XVIII heparan sulfate proteoglycans. Receptor engagement elicits various downstream effects including tyrosine kinase and gene activation. Much remains to be learned, however, about details of the signal transduction cascades and how they interfere with pro-angiogenic factors under physiological conditions and during therapeutic treatment.

Publication Types:
Review

PMID: 12049199 [PubMed - indexed for MEDLINE]

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8: Pharm Unserer Zeit. 2001;30(6):488-94.


[Supporting function of collagen and hydroxyapatite. Structure and function of bone]

[Article in German]

Felsenberg D.

Universitätsklinikum Benjamin Franklin Ragiologische Klinik und Poliklinik Hindenburgdamm 30 12200 Berlin.

Publication Types:
Review

PMID: 11715680 [PubMed - indexed for MEDLINE]

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9: Seikagaku. 1999 Jun;71(6):432-8.


[Diversified expression and function of minor fibrillar collagen]

[Article in Japanese]

Yoshioka H.

Department of Biochemistry, Oita Medical University.

Publication Types:
Review

PMID: 10432836 [PubMed - indexed for MEDLINE]

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10: Matrix Biol. 1998 Feb;16(7):379-86.


Expression and function of heat shock protein 47: a collagen-specific molecular chaperone in the endoplasmic reticulum.

Nagata K.

Department of Cell Biology, Kyoto University, Japan.

Heat shock protein (HSP) 47 is a collagen-binding stress protein localized in the endoplasmic reticulum (ER). In addition to stress-inducibility through heat shock element-heat shock factor interaction, the expression of HSP47 under normal conditions always correlates with that of collagens in various cell types and tissues. Both HSP47 and types I and III collagens are also dramatically induced under pathophysiological conditions such as liver fibrosis. HSP47 transiently associates with procollagen in the ER and dissociates from it in the cis-Golgi compartment. Possible functions of HSP47 as a molecular chaperone specific for procollagen are discussed: prevention of nascent procollagen chains from forming aggregates, effect on the modification of procollagen, inhibition of intracellular degradation of procollagen, quality control mechanisms under stress conditions, and effect on the secretion from the ER to the Golgi compartment.

Publication Types:
Review

PMID: 9524358 [PubMed - indexed for MEDLINE]

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11: Bone. 1998 Mar;22(3):181-7.


Collagen cross-links in mineralizing tissues: a review of their chemistry, function, and clinical relevance.

Knott L, Bailey AJ.

Collagen Research Group, Division of Molecular and Cellular Biology, University of Bristol, Langford, UK. l.knott@bris.ac.uk

Bone collagen cross-links are now widely used to assess bone resorption levels in many metabolic bone diseases. The post-translational modifications of bone and other mineralizing collagens are significantly different from those of other type I collagen matrices, a fact that has been exploited during recent advances in the development of biochemical markers of bone resorption. The enzymatic collagen cross-linking mechanism is based upon aldehyde formation from specific telopeptide lysine or hydroxylysine residues. The immature ketoimine cross-links in bone form via the condensation of a telopeptide aldehyde with a helical lysine or hydroxylysine. Subsequent maturation to the pyridinoline and pyrrole cross-links occur by further reaction of the ketoimines with telopeptide aldehydes. In mineralizing tissues, a relatively low level of lysyl hydroxylation results in low levels of hydroxylysyl pyridinoline, and the occurrence of the largely bone specific lysyl pyridinoline and pyrrolic cross-links. The collagen post-translational modifications appear to play an integral role in matrix mineralization. The matrix of the turkey tendon only mineralizes after a remodeling of the collagen and the subsequent formation of a modified matrix more typical of bone than tendon. Further, disturbances in the post-translational modification of collagen can also affect the mineralization density and crystal structure of the tissue. In addition to their use as a convenient measure of matrix degradation, collagen cross-links are of significant importance for the biomechanical integrity of bone. Recent studies of osteoporotic bone, for example, have demonstrated that subtle perturbations in the pattern of lysine hydroxylation result in changes in the cross-link profile. These alterations, specifically changes in the level of the pyrrolic cross-link, also correlate with the strength of the bone. Further research into the biochemistry of bone collagen cross-links may expand current understanding and their clinical application in metabolic bone disease. This review also demonstrates the potential for further study into this area to provide more subtle information into the mechanisms and etiology of disease and aging of mineralizing tissues.

Publication Types:
Review

PMID: 9514209 [PubMed - indexed for MEDLINE]

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12: Cell Struct Funct. 1996 Oct;21(5):425-30.


Regulation and function of collagen-specific molecular chaperone, HSP47.

Nagata K, Hosokawa N.

Department of Cell Biology, Kyoto University, Japan. nagata@chest.kyoto-u.ac.jp

Publication Types:
Review

PMID: 9118251 [PubMed - indexed for MEDLINE]

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13: Kaibogaku Zasshi. 1995 Aug;70(4):298-306.


[Tissue localization and possible function of type VI collagen]

[Article in Japanese]

Kobayashi M.

Department of Anatomy, Nagoya University School of Medicine, Japan.

Type VI collagen was once considered a minor collagen, but now it is known as a major component of the extracellular matrices of most tissues. Type VI collagen tetramers aggregate into beaded filaments with repeats of approximately 100 nm, and the beaded filaments align laterally to form type VI collagen periodic fibrils by incubation with acidic ATP solution. Polyanionic ATP could cause lateral alignment of type VI collagen beaded filaments. Since the periodic structure is observable by transmission electron microscopy, we can examine the tissue distribution of type VI collagen by ATP treatment. Moreover, the interaction of type VI collagen with other extracellular matrix components can be examined by combining ruthenium red (RR) staining, which specifically interacts with tissue glycosaminoglycans (GAGs), with the ATP treatment. I here describe the localization and possible function of type VI collagen examined in our laboratory. After ATP incubation, numerous type VI collagen periodic fibrils appeared closely associated with striated collagen fibrils (mouse cornea and fibrous layer of mandibular condyle), with trophoblastic and endothelial basal lamina (human placenta), or with cell surface of fibroblasts (mouse tendon) and synovial cells (mouse synovium). The dark bands of the type VI collagen periodic fibrils were stained by RR, indicating the association of proteoglycans (PGs)/GAGs with this collagen. If the mouse corneal tissue was digested with chondroitinase ABC or testicular hyaluronidase prior to ATP treatment, type VI collagens were segregated to form periodic structures apart from striated collagen fibrils. In the mouse mandibular condyle, hyaluronidase digestion before ATP treatment caused unmasking of type VI collagen.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication Types:
English Abstract
Review

PMID: 8540277 [PubMed - indexed for MEDLINE]

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14: J Mol Cell Cardiol. 1994 Mar;26(3):279-92.


Collagen network of the myocardium: function, structural remodeling and regulatory mechanisms.

Weber KT, Sun Y, Tyagi SC, Cleutjens JP.

Department of Internal Medicine, University of Missouri Health Sciences Center, Columbia 65212.

A collagen network, composed largely of type I and III fibrillar collagens, is found in the extracellular space of the myocardium. This network has multiple functions which includes a preservation of tissue architecture and chamber geometry. Given its tensile strength, collagen is a major determinant of tissue stiffness. Its disproportionate accumulation, in the form of either a reactive or a reparative fibrosis, further increases stiffness. A degradation of collagen tethers, on the other hand, is an anatomic requisite for a distortion in tissue architecture and a reduction in stiffness that can lead to chamber dilatation, wall thinning, and even rupture of the myocardium. Collagen turnover in the myocardium is dynamic. When synthesis exceeds degradation, an adverse accumulation of collagen appears to distort tissue structure. This is true for either the hypertrophied and/or nonhypertrophied ventricle. Factors that contribute to the appearance of myocardial fibrosis are largely different from those that promote cardiac myocyte growth. Included amongst these fibrogenic factors are effector hormones of the reinin-angiotensin-aldosterone system (RAAS). Studies conducted both in intact animals (relative to dietary sodium intake) and in cultured adult cardiac fibroblasts have pointed toward the association between collagen accumulation and chronic elevations in circulating angiotensin II and aldosterone. A tissue hormonal system involving angiotensin II, endothelins and bradykinin, may likewise regulate fibrogenesis. In this regard, angiotensin converting enzyme is found in connective tissue of the normal heart, including the matrix of heart valves and the adventitia of the intramural coronary arteries, and fibrous tissue that forms following infarction or with chronic RAAS activation. The importance of ACE in the regulation of local angiotensin II and bradykinin levels and their contribution to collagen turnover is a fruitful area of research with important clinical implications. The myocardium also contains a proteolytic system, including collagenase. The characteristics and regulation of matrix metalloproteinases and their tissue inhibitors in various cardiovascular disease states requires further investigation.

Publication Types:
Review

PMID: 8028011 [PubMed - indexed for MEDLINE]

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15: Biochem Soc Trans. 1993 May;21(2):464-8.


Structure/function relationships in the collectins (mammalian lectins containing collagen-like regions).

Reid KB.

Department of Biochemistry, University of Oxford, U.K.

Publication Types:
Review

PMID: 8359511 [PubMed - indexed for MEDLINE]

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16: Braz J Med Biol Res. 1992;25(10):975-82.


Myocardial collagen remodeling and left ventricular diastolic function.

Janicki JS.

Department of Internal Medicine, University of Missouri, Columbia 65212.

1. The myocardial collagen matrix is an active participant in determining ventricular architecture and diastolic function, and myocardial structural integrity and mechanical properties. It consists of a network of fibrillar collagen which is intimately related with the myocyte, myofibril and muscle fiber as well as the coronary vasculature. Consisting primarily of collagen types I and III, this material exhibits a high tensile strength which, even though normally present in relatively small amounts, plays an important role in the behavior of the ventricle during diastole. 2. Removal of less than half of the normal amount of collagen results in a dilated ventricle with increased compliance. Collagen degradation of this magnitude and similar myocardial and ventricle with increased compliance. Collagen degradation of this magnitude and similar myocardial and ventricular histologic and functional alterations are evident during ischemia and in dilated cardiomyopathy. Thus, it would appear that a chronic change in the shape and size of the heart must be preceded by alterations in the interstitial collagen matrix. 3. With elevations in the circulating levels of angiotensin and/or mineralocorticoids, the hypertrophic response of the myocardium to the accompanying hypertension includes a progressive remodeling of the collagen component. Typically there is an increase in collagen concentration, thickening of existing fibrillar collagen and the addition of new collagen at all levels of the matrix. The consequences of this remodeling are an adverse alteration of the passive mechanical properties of the myocardium and LV diastolic dysfunction. This pathophysiologic aspect of the hypertrophic process is independent of the concomitant remodeling of the myocyte.(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: 1342831 [PubMed - indexed for MEDLINE]

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17: Ann N Y Acad Sci. 1990;580:32-43.


The structure and function of type VII collagen.

Burgeson RE, Lunstrum GP, Rokosova B, Rimberg CS, Rosenbaum LM, Keene DR.

Shriners Hospital for Crippled Children, Portland, Oregon 97201.

Publication Types:
Review

PMID: 2186694 [PubMed - indexed for MEDLINE]

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18: Tanpakushitsu Kakusan Koso. 1986 Jan;31(1):29-52.


[Collagen--its function and metabolism]

[Article in Japanese]

Hata R.

Publication Types:
Review

PMID: 3520675 [PubMed - indexed for MEDLINE]

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19: Birth Defects Orig Artic Ser. 1984;20(3):65-77.


Lethal mutations in type I collagen: structure-function relationships in the type I collagen molecule.

Byers PH, Bonadio JF.

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

PMID: 6391576 [PubMed - indexed for MEDLINE]

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20: Semin Arthritis Rheum. 1983 Aug;13(1):1-86.


Collagen: structure, function, and metabolism in normal and fibrotic tissues.

Nimni ME.

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

PMID: 6138859 [PubMed - indexed for MEDLINE]
 

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