scholarly journals Chemistry of the collagen cross-links. Nature of the cross-links in the polymorphic forms of dermal collagen during development

1976 ◽  
Vol 153 (2) ◽  
pp. 211-215 ◽  
Author(s):  
A J Bailey ◽  
T J Sims
Keyword(s):  
Postnatal Development ◽  
Type I Collagen ◽  
Significant Proportion ◽  
Type I ◽  
Cross Link ◽  
Lysine Residues ◽  
Dermal Collagen ◽  
Cross Links ◽  
Polymorphic Forms ◽  
The Cross

Both the type I and type III collagens present in embryonic dermis are stabilized by the intermolecular cross-link, hydroxylysino-5-oxonorleucine, derived from hydroxylysine-aldehyde, although the type I collagen possesses a significant proportion of dehydrohydroxylysinonorleucine. However, concurrent with the change in the proportion of the two types of collagen during postnatal development there is a change-over with both type I and III collagens to the labile cross-link, dehydrohydroxylysinonorleucine, derived from lysine aldehyde. The results indicate that the change in the nature of the cross-link with development is determined primarily by the change in the extent of hydroxylation of the lysine residues in the terminal non-helical regions rather than being due to the change in the type of collagen.

scholarly journals Chemistry of collagen cross-linking: biochemical changes in collagen during the partial mineralization of turkey leg tendon

1997 ◽  
Vol 322 (2) ◽  
pp. 535-542 ◽  
Author(s):  
Lynda KNOTT ◽  
John F. TARLTON ◽  
Allen J. BAILEY
Keyword(s):  
Collagen Matrix ◽  
Cross Linking ◽  
Cross Link ◽  
Lysine Residues ◽  
Collagen Mineralization ◽  
Cross Links ◽  
The Cross ◽  
Calcified Tissues ◽  
Turkey Leg Tendon ◽  
Collagen Cross Linking

With age, the proximal sections of turkey leg tendons become calcified, and this phenomenon has led to their use as a model for collagen mineralization. Mineralizing turkey leg tendon was used in this study to characterize further the composition and cross-linking of collagen in calcified tissues. The cross-link profiles of mineralizing collagen are significantly different from those of other collagenous matrices with characteristically low amounts of hydroxylysyl-pyridinoline and the presence of lysyl-pyridinoline and pyrrolic cross-links. However, the presence of the immature cross-link precursors previously reported in calcifying tissues was not supported in the present study, and was found to be due to the decalcification procedure using EDTA. Analysis of tendons from young birds demonstrated differences in the cross-link profile which indicated a higher level of hydroxylation of specific triple-helical lysines involved in cross-linking of the proximal tendon. This may be related to later calcification, suggesting that this part of the tendon is predestined to be calcified. The minimal changes in lysyl hydroxylation in both regions of the tendon with age were in contrast with the large changes in the cross-link profile, indicating differential hydroxylation of the helical and telopeptide lysine residues. Changes with age in the collagen matrix, its turnover and thermal properties in both the proximal and distal sections of the tendon clearly demonstrate that a new and modified matrix is formed throughout the tendon, and that a different type of matrix is formed at each site.

Changes in mechanical properties, thermal stability, reducible cross-links and glycosyl-lysines in rat skin induced by corticosteroid treatment

1982 ◽  
Vol 101 (2) ◽  
pp. 312-320 ◽  
Author(s):  
Hans Oxlund ◽  
Trevor Sims ◽  
Nicholas D. Light
Keyword(s):  
Thermal Stability ◽  
Type I Collagen ◽  
Corticosteroid Treatment ◽  
Biochemical Properties ◽  
Type Iii Collagen ◽  
Type I ◽  
Clinical Observations ◽  
Skin Collagen ◽  
Lysine Residues ◽  
Cross Links

Abstract. The effects of systemic cortisol treatment on the biophysical and biochemical properties of skin were investigated. Rats were injected sc with cortisol for 14, 60 and 120 days and samples of lumbar skin were studied. Corticosteroids exert a biphasic effect on the strength of skin: 1) a relatively fast increase in the strength and stability, caused by an increased collagen cross-linking and 2) an inhibited collagen synthesis which ultimately results in a thinning of the skin and a decrease of collagen content consistent with clinical observations. The thermal stability is increased indicating an increased proportion of thermostable cross-links in skin collagen. No changes are observed in the percentage type III collagen with respect to type I collagen. Increased amounts of glucose attached to the ε-amino group of lysine residues in the collagen are found after long-term treatments, an alteration which may play a role in hampering the tissue functions.

scholarly journals Lysine post-translational modifications of collagen

2012 ◽  
Vol 52 ◽  
pp. 113-133 ◽  
Author(s):  
Mitsuo Yamauchi ◽  
Marnisa Sricholpech
Keyword(s):  
Molecular Mechanisms ◽  
Type I Collagen ◽  
Biological Significance ◽  
Helical Structure ◽  
Cross Linking ◽  
Type I ◽  
Structural Protein ◽  
Post Translational Modifications ◽  
Lysine Residues ◽  
Cross Links

Type I collagen is the most abundant structural protein in vertebrates. It is a heterotrimeric molecule composed of two α1 chains and one α2 chain, forming a long uninterrupted triple helical structure with short non-triple helical telopeptides at both the N- and C-termini. During biosynthesis, collagen acquires a number of post-translational modifications, including lysine modifications, that are critical to the structure and biological functions of this protein. Lysine modifications of collagen are highly complicated sequential processes catalysed by several groups of enzymes leading to the final step of biosynthesis, covalent intermolecular cross-linking. In the cell, specific lysine residues are hydroxylated to form hydroxylysine. Then specific hydroxylysine residues located in the helical domain of the molecule are glycosylated by the addition of galactose or glucose-galactose. Outside the cell, lysine and hydroxylysine residues in the N- and C-telopeptides can be oxidatively deaminated to produce reactive aldehydes that undergo a series of non-enzymatic condensation reactions to form covalent intra- and inter-molecular cross-links. Owing to the recent advances in molecular and cellular biology, and analytical technologies, the biological significance and molecular mechanisms of these modifications have been gradually elucidated. This chapter provides an overview on these enzymatic lysine modifications and subsequent cross-linking.

scholarly journals Collagen molecular phenotypic switch between non-neoplastic and neoplastic canine mammary tissues

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masahiko Terajima ◽  
Yuki Taga ◽  
Becky K. Brisson ◽  
Amy C. Durham ◽  
Kotaro Sato ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mammary Gland ◽  
Mammary Carcinoma ◽  
Cancer Biology ◽  
Type I Collagen ◽  
Critical Role ◽  
Premature Death ◽  
Mammary Tissue ◽  
Type I ◽  
Cross Links

AbstractIn spite of major advances over the past several decades in diagnosis and treatment, breast cancer remains a global cause of morbidity and premature death for both human and veterinary patients. Due to multiple shared clinicopathological features, dogs provide an excellent model of human breast cancer, thus, a comparative oncology approach may advance our understanding of breast cancer biology and improve patient outcomes. Despite an increasing awareness of the critical role of fibrillar collagens in breast cancer biology, tumor-permissive collagen features are still ill-defined. Here, we characterize the molecular and morphological phenotypes of type I collagen in canine mammary gland tumors. Canine mammary carcinoma samples contained longer collagen fibers as well as a greater population of wider fibers compared to non-neoplastic and adenoma samples. Furthermore, the total number of collagen cross-links enriched in the stable hydroxylysine-aldehyde derived cross-links was significantly increased in neoplastic mammary gland samples compared to non-neoplastic mammary gland tissue. The mass spectrometric analyses of type I collagen revealed that in malignant mammary tumor samples, lysine residues, in particular those in the telopeptides, were markedly over-hydroxylated in comparison to non-neoplastic mammary tissue. The extent of glycosylation of hydroxylysine residues was comparable among the groups. Consistent with these data, expression levels of genes encoding lysyl hydroxylase 2 (LH2) and its molecular chaperone FK506-binding protein 65 were both significantly increased in neoplastic samples. These alterations likely lead to an increase in the LH2-mediated stable collagen cross-links in mammary carcinoma that may promote tumor cell metastasis in these patients.

scholarly journals Microtubules and microtubule-associated proteins from the nematode Caenorhabditis elegans: periodic cross-links connect microtubules in vitro.

1986 ◽  
Vol 103 (1) ◽  
pp. 23-31 ◽  
Author(s):  
E J Aamodt ◽  
J G Culotti
Keyword(s):  
Caenorhabditis Elegans ◽  
Apparent Molecular Weight ◽  
Cross Link ◽  
Nematode Caenorhabditis Elegans ◽  
Microtubule Associated Proteins ◽  
C Elegans ◽  
Associated Proteins ◽  
Cross Links ◽  
The Cross

The nematode Caenorhabditis elegans should be an excellent model system in which to study the role of microtubules in mitosis, embryogenesis, morphogenesis, and nerve function. It may be studied by the use of biochemical, genetic, molecular biological, and cell biological approaches. We have purified microtubules and microtubule-associated proteins (MAPs) from C. elegans by the use of the anti-tumor drug taxol (Vallee, R. B., 1982, J. Cell Biol., 92:435-44). Approximately 0.2 mg of microtubules and 0.03 mg of MAPs were isolated from each gram of C. elegans. The C. elegans microtubules were smaller in diameter than bovine microtubules assembled in vitro in the same buffer. They contained primarily 9-11 protofilaments, while the bovine microtubules contained 13 protofilaments. The principal MAP had an apparent molecular weight of 32,000 and the minor MAPs were 30,000, 45,000, 47,000, 50,000, 57,000, and 100,000-110,000 mol wt as determined by SDS-gel electrophoresis. The microtubules were observed, by electron microscopy of negatively stained preparations, to be connected by stretches of highly periodic cross-links. The cross-links connected the adjacent protofilaments of aligned microtubules, and occurred at a frequency of one cross-link every 7.7 +/- 0.9 nm, or one cross-link per tubulin dimer along the protofilament. The cross-links were removed when the MAPs were extracted from the microtubules with 0.4 M NaCl. The cross-links then re-formed when the microtubules and the MAPs were recombined in a low salt buffer. These results strongly suggest that the cross-links are composed of MAPs.

EXPERIMENTAL VALIDATION OF THE CHARLESBY AND HORIKX MODELS APPLIED TO DE-VULCANIZATION OF SULFUR AND PEROXIDE VULCANIZATES OF NR AND EPDM

2016 ◽  
Vol 89 (4) ◽  
pp. 671-688 ◽  
Author(s):  
M. A. L. Verbruggen ◽  
L. van der Does ◽  
W. K. Dierkes ◽  
J. W. M. Noordermeer
Keyword(s):  
Experimental Validation ◽  
Main Chain ◽  
Sol Gel ◽  
Chain Scission ◽  
Cross Linking ◽  
Cross Link ◽  
Practical Reality ◽  
Cross Links ◽  
The Cross ◽  
Theoretical Considerations

ABSTRACT The theoretical model developed by Charlesby to quantify the balance between cross-links creation of polymers and chain scission during radiation cross-linking and further modifications by Horikx to describe network breakdown from aging were merged to characterize the balance of both types of scission on the development of the sol content during de-vulcanization of rubber networks. There are, however, disturbing factors in these theoretical considerations vis-à-vis practical reality. Sulfur- and peroxide-cured NR and EPDM vulcanizates were de-vulcanized under conditions of selective cross-link and random main-chain scissions. Cross-link scission was obtained using thiol-amine reagents for selective cleavage of sulfur cross-links. Random main-chain scission was achieved by heating peroxide vulcanizates of NR with diphenyldisulfide, a method commonly employed for NR reclaiming. An important factor in the analyses of these experiments is the cross-linking index. Its value must be calculated using the sol fraction of the cross-linked network before de-vulcanization to obtain reliable results. The values for the cross-linking index calculated with sol-gel data before de-vulcanization appear to fit the experimentally determined modes of network scission during de-vulcanization very well. This study confirms that the treatment of de-vulcanization data with the merged Charlesby and Horikx models can be used satisfactorily to characterize the de-vulcanization of NR and EPDM vulcanizates.

scholarly journals Protease-dependent versus -independent cancer cell invasion programs: three-dimensional amoeboid movement revisited

2009 ◽  
Vol 185 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Farideh Sabeh ◽  
Ryoko Shimizu-Hirota ◽  
Stephen J. Weiss
Keyword(s):  
Cancer Cells ◽  
Type I Collagen ◽  
Three Dimensional ◽  
Amoeboid Movement ◽  
Type I ◽  
Collagen Network ◽  
Normal Tissues ◽  
Tissue Invasion ◽  
Absolute Requirement ◽  
Cross Links

Tissue invasion during metastasis requires cancer cells to negotiate a stromal environment dominated by cross-linked networks of type I collagen. Although cancer cells are known to use proteinases to sever collagen networks and thus ease their passage through these barriers, migration across extracellular matrices has also been reported to occur by protease-independent mechanisms, whereby cells squeeze through collagen-lined pores by adopting an ameboid phenotype. We investigate these alternate models of motility here and demonstrate that cancer cells have an absolute requirement for the membrane-anchored metalloproteinase MT1-MMP for invasion, and that protease-independent mechanisms of cell migration are only plausible when the collagen network is devoid of the covalent cross-links that characterize normal tissues.

scholarly journals Magnetic composites based on NR and strontium ferrite

2019 ◽  
Vol 12 (1) ◽  
pp. 63-69
Author(s):  
Ján Kruželák ◽  
Andrea Kvasničáková ◽  
Rastislav Dosoudil ◽  
Ivan Hudec
Keyword(s):  
Carbon Black ◽  
Strontium Ferrite ◽  
Rubber Matrix ◽  
Cross Link ◽  
Magnetic Composites ◽  
Link Density ◽  
Cross Links ◽  
Cross Link Density ◽  
The Cross ◽  
Thermo Physical Properties

Abstract Two types of composites based on natural rubber (NR) and strontium ferrite were tested in this study. Composites of the first type were prepared by incorporation of strontium ferrite in the concentration range ranging from 0 to 100 phr (parts per hundred rubber) into pure NR based rubber matrix, while with those of the second type, strontium ferrite was dosed in the same concentration level into NR based rubber batch with constant amount of carbon black — 25 phr. For rubber matrices cross-linking, a standard sulfur based curing system was used. This work is focused on the effect of magnetic filler content on physico-mechanical, magnetic and thermo-physical properties of composite materials. Subsequently, the cross-link density and the structure of the formed sulfidic cross-links were examined. The results showed that the cross-link density of both types of composites increased with the increasing content of magnetic filler, while the structure of the sulfidic cross-links was almost not influenced by the amount of strontium ferrite. Tensile strength of rubber composites with pure rubber matrix was slightly improved by the incorporation of ferrite, while in case of composites based on a carbon black batch, the incorporation of magnetic filler resulted in the decrease of this characteristic. The presence of magnetic filler in both types of composites leads to a significant increase of the remanent magnetic induction.

scholarly journals Biosynthesis of sulphated macromolecules by rabbit lens epithelium. II. Relationship to basement membrane formation.

1984 ◽  
Vol 99 (3) ◽  
pp. 861-869 ◽  
Author(s):  
J G Heathcote ◽  
R R Bruns ◽  
R W Orkin
Keyword(s):  
Basement Membrane ◽  
Type I Collagen ◽  
Heparan Sulphate ◽  
Significant Proportion ◽  
Type I ◽  
Heparan Sulphate Proteoglycan ◽  
Membrane Formation ◽  
Sulphate Proteoglycan ◽  
Type Iv ◽  
Rabbit Lens

Rabbit lens epithelial cells display a similar "cobblestone" morphology and produce the same complement of sulphated macromolecules (also see Heathcote, J.G., and R.W. Orkin, 1984, J. Cell Biol., 99:852-860) whether grown on plastic or glass, dried films of gelatin or type IV collagen with laminin, or on gels of type I collagen. There was no evidence of basement membrane formation by these cells when they were grown on plastic, glass, or dried films. In contrast, cultures that had been grown on gels deposited a discrete basement membrane that followed the contours of the basal surfaces of the cells and in addition, they secreted amorphous basement membrane-like material that diffused into the interstices of the gel and associated with the collagen fibrils of the gel. A significant proportion (approximately 70%) of the heparan sulphate proteoglycan fraction that was secreted into the culture medium (fraction MI) when the cells were grown on plastic became associated with the cell-gel layer in the gel cultures. Further, when basement membrane was isolated by detergent extraction, greater than 90% of the 35S-labeled material present was in this heparan sulphate proteoglycan.

scholarly journals Dynamic Stretching of Fibrillar Collagen Enhances Cross-linking by Transglutaminas

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0038
Author(s):  
Nicolas Shealy ◽  
James Rex ◽  
Amy Bradshaw ◽  
Christopher Gross
Keyword(s):  
Molecular Weight ◽  
Type I Collagen ◽  
Cross Linking ◽  
Type I ◽  
Fibrillar Collagen ◽  
Collagen Gels ◽  
Cross Link ◽  
Dynamic Stretching ◽  
Insoluble Collagen ◽  
Static Conditions

Category: Basic Sciences/Biologics Introduction/Purpose: New approaches to improve tendon repair after injury are an active area of research. Critical properties of tendons are governed by the production and assembly of fibrillar collagens. Cross-linking of fibrillar collagen is a primary factor in determining the function and mechanical properties of the collagen fibers comprising Enzymatic cross-linking by lysyl oxidase in the telopeptide domain of collagen I and III is one determinant of collagen fibril assembly and is the best characterized biochemical cross-link. Transglutaminase catalyzes the modification of lysine residues that in turn form an n-e-glutamyl lysine bond between proteins in the extracellular space. We hypothesize that transglutaminase-dependent modification of collagen in tendons is also a principal determinant of tendon strength and function and is dependent upon tension. Methods: 3-D collagen gels were generated from acid solubilized type I collagen with telopeptides (Advanced BioMatrix). Collagen gels were plated and loaded into a MechanoCulture FX apparatus (CellScale). Gels were subjected to a 10% stretch for 24 hrs at 37°C at 2hz (dynamic) or no stretch, static controls. Gels exposed to enzymatic cross-linking were incubated with either 2.4 ng of recombinant Transglutaminase 2 (Axxora) in a 10 mM Ca2+ solution. Inhibition and labeling of transglutaminase substrates was performed by incubation of collagen gels with 0.2 mM aminopentyl biotinamide in DMSO. Soluble collagen was separated from insoluble collagen by centrifugation at 10,000G. Insoluble fractions were boiled in SDS-Laemmli buffer prior to separation by SDS-PAGE. Collagen in soluble and insoluble fractions was evaluated by Coomassie stain whereas transglutaminase modification was detected via western blot using streptavidin conjugated horse radish peroxidase to detect biotinylated proteins. Results: Evaluation of collagen gels subjected to dynamic versus static stretch revealed minor differences in insoluble collagen incorporation in the two conditions. Notably, higher molecular weight cross-linked forms of collagen appeared to be higher in dynamic versus static gels. In the presence of transglutaminase, differences in higher molecular weight cross-linked forms of collagen, beta-bands, were also detected. Finally, incorporation of biotinylated transglutaminase substrate into collagen alpha bands was enriched in dynamic versus static cultures. Hence, preliminary results support a differential role for transglutaminase modification in collagen under cyclic tension versus static conditions. Conclusion: A better understanding of the role of dynamic stretching and differential tension in the regulation of collagen cross- link formation is predicted to contribute to improved strategies to treat injured tendons.

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