Collagen-the Ultrastructural Element of the Bone Matrix

2018 ◽  
Vol 69 (7) ◽  
pp. 1706-1709
Author(s):  
Nicoleta Dumitru ◽  
Andra Cocolos ◽  
Andra Caragheorgheopol ◽  
Constantin Dumitrache ◽  
Ovidiu Gabriel Bratu ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Bone Microarchitecture ◽  
Complex Structure ◽  
Bone Matrix ◽  
Organic Matrix ◽  
Bone Diseases ◽  
Bone Collagen ◽  
Type I ◽  
New Therapeutic Approaches ◽  
And Function

There is an increased interest and more studies highlight the fact that bone strength depends not only on bone tissue quantity, but also on its quality, which is characterized by the geometry and shape of bones, trabecular bone microarchitecture, mineral content, organic matrix and bone turnover. Fibrillar type I collagen is the major organic component of bone matrix, providing form and a stable template for mineralization. The biomedical importance of collagen as a biomaterial for medical and cosmetic purposes and the improvement of the molecular, cellular biology and analytical technologies, led to increasing interest in establishing the structure of this protein and in setting of the relationships between sequence, structure, and function. Bone collagen crosslinking chemistry and its molecular packing structure are considered to be distinct features. This unique post-translational modifications provide to the fibrillar collagen matrices properties such as tensile strength and viscoelasticity. Understanding the complex structure of bone type I collagen as well as the dynamic nature of bone tissues will help to manage new therapeutic approaches to bone diseases.

scholarly journals Estrogen Reduces the Depth of Resorption Pits by Disturbing the Organic Bone Matrix Degradation Activity of Mature Osteoclasts

Endocrinology ◽  
2001 ◽  
Vol 142 (12) ◽  
pp. 5371-5378 ◽  
Author(s):  
Vilhelmiina Parikka ◽  
Petri Lehenkari ◽  
Mirja-Liisa Sassi ◽  
Jussi Halleen ◽  
Juha Risteli ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Type I Collagen ◽  
Bone Matrix ◽  
Organic Matrix ◽  
Cysteine Proteases ◽  
Bone Collagen ◽  
Type I ◽  
Matrix Degradation ◽  
Carboxyl Terminal

Abstract Decreased E2 levels after menopause cause bone loss through increased penetrative resorption. The reversal effect of E2 substitution therapy is well documented in vivo, although the detailed mechanism of action is not fully understood. To study the effects of E2 on bone resorption, we developed a novel in vitro bone resorption assay in which degradation of inorganic and organic matrix could be measured separately. E2 treatment significantly decreased the depth of resorption pits, although the area resorbed was not changed. Electron microscopy further revealed that the resorption pits were filled with nondegraded collagen, suggesting that E2 disturbed the organic matrix degradation. Two major groups of proteinases, matrix metalloproteinases (MMPs) and cysteine proteinases, have been suggested to participate in organic matrix degradation by osteoclasts. We show here that MMP-9 released a cross-linked carboxyl-terminal telopeptide of type I collagen from bone collagen, and cathepsin K released another C-terminal fragment, the C-terminal cross-linked peptide of type I collagen. E2 significantly inhibited the release of the C-terminal cross-linked peptide of type I collagen into the culture medium without affecting the release of cross-linked carboxyl-terminal telopeptide of type I collagen in osteoclast cultures. These results suggest that organic matrix degradation is initiated by MMPs and continued by cysteine proteases; the latter event is regulated by E2.

scholarly journals From Stem Cells to Bone-Forming Cells

2021 ◽  
Vol 22 (8) ◽  
pp. 3989
Author(s):  
Samantha Donsante ◽  
Biagio Palmisano ◽  
Marta Serafini ◽  
Pamela G. Robey ◽  
Alessandro Corsi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Type I Collagen ◽  
Bone Matrix ◽  
Bone Modeling ◽  
Type I ◽  
Regulatory Pathways ◽  
Stage Of Development ◽  
Metabolic Activities ◽  
And Function ◽  
And Control

Bone formation starts near the end of the embryonic stage of development and continues throughout life during bone modeling and growth, remodeling, and when needed, regeneration. Bone-forming cells, traditionally termed osteoblasts, produce, assemble, and control the mineralization of the type I collagen-enriched bone matrix while participating in the regulation of other cell processes, such as osteoclastogenesis, and metabolic activities, such as phosphate homeostasis. Osteoblasts are generated by different cohorts of skeletal stem cells that arise from different embryonic specifications, which operate in the pre-natal and/or adult skeleton under the control of multiple regulators. In this review, we briefly define the cellular identity and function of osteoblasts and discuss the main populations of osteoprogenitor cells identified to date. We also provide examples of long-known and recently recognized regulatory pathways and mechanisms involved in the specification of the osteogenic lineage, as assessed by studies on mice models and human genetic skeletal diseases.

Role of Host-Derived Proteinases in Dentine Caries and Erosion

2015 ◽  
Vol 49 (Suppl. 1) ◽  
pp. 30-37 ◽  
Author(s):  
Marília Afonso Rabelo Buzalaf ◽  
Senda Charone ◽  
Leo Tjäderhane
Keyword(s):  
Structural Changes ◽  
Type I Collagen ◽  
Organic Matrix ◽  
Collagen Matrix ◽  
Type I ◽  
Cysteine Cathepsins ◽  
Gradual Loss ◽  
Collagen Molecules ◽  
And Function

Demineralization in dentinal caries and erosion exposes dentine organic matrix. This exposed matrix, containing type I collagen and non-collagenous proteins, is then degraded by host collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins. The knowledge of the identities and function of these enzymes in dentine has accumulated only within the last 15 years, but has already formed a field of research called ‘dentine degradomics'. This research has demonstrated the role of endogenous collagenolytic enzymes in caries and erosion development. In demineralized dentine, the enzymes degrade triple-helical collagen molecules, leading to the gradual loss of collagen matrix. Even before that, they can cleave off the terminal non-helical ends of collagen molecules called telopeptides, leading to the structural changes at the intramolecular gap areas, which may affect or even prevent intrafibrillar remineralization, which is considered essential in restoring the dentine's mechanical properties. They may also cause the loss of non-collagenous proteins that could serve as nucleation sites for remineralization. Here we review the findings demonstrating that inhibition of salivary or dentine endogenous MMPs and cysteine cathepsins may provide preventive means against the progression of caries or erosion. Furthermore, we also suggest the future directions for the new experimental preventive research to gain more knowledge of the enzymes and their function during and after dentine demineralization, and the pathways to find the clinically acceptable means to prevent the functional activity of these enzymes.

scholarly journals Protective Effect of Ciclopirox against Ovariectomy-Induced Bone Loss in Mice by Suppressing Osteoclast Formation and Function

2021 ◽  
Vol 22 (15) ◽  
pp. 8299
Author(s):  
Hye Jung Ihn ◽  
Jiwon Lim ◽  
Kiryeong Kim ◽  
Sang-Hyeon Nam ◽  
Soomin Lim ◽  
...  
Keyword(s):  
Bone Loss ◽  
Type I Collagen ◽  
Osteoclast Differentiation ◽  
Osteoclast Formation ◽  
Bone Diseases ◽  
Mitogen Activated Protein Kinase ◽  
Type I ◽  
And Function

Postmenopausal osteoporosis is closely associated with excessive osteoclast formation and function, resulting in the loss of bone mass. Osteoclast-targeting agents have been developed to manage this disease. We examined the effects of ciclopirox on osteoclast differentiation and bone resorption in vitro and in vivo. Ciclopirox significantly inhibited osteoclast formation from primary murine bone marrow macrophages (BMMs) in response to receptor activator of nuclear factor kappa B ligand (RANKL), and the expression of genes associated with osteoclastogenesis and function was decreased. The formation of actin rings and resorption pits was suppressed by ciclopirox. Analysis of RANKL-mediated early signaling events in BMMs revealed that ciclopirox attenuates IκBα phosphorylation without affecting mitogen-activated protein kinase activation. Furthermore, the administration of ciclopirox suppressed osteoclast formation and bone loss in ovariectomy-induced osteoporosis in mice and reduced serum levels of osteocalcin and C-terminal telopeptide fragment of type I collagen C-terminus. These results indicate that ciclopirox exhibits antiosteoclastogenic activity both in vitro and in vivo and represents a new candidate compound for protection against osteoporosis and other osteoclast-related bone diseases.

scholarly journals Support of bone mineral deposition by regulation of pH

2018 ◽  
Vol 315 (4) ◽  
pp. C587-C597 ◽  
Author(s):  
Harry C. Blair ◽  
Quitterie C. Larrouture ◽  
Irina L. Tourkova ◽  
Li Liu ◽  
Jing Hao Bian ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Extracellular Space ◽  
Type I Collagen ◽  
Bone Matrix ◽  
Membrane Vesicles ◽  
Bone Collagen ◽  
Type I ◽  
Mineral Deposition ◽  
The Matrix ◽  
Ph Dependent

Osteoblasts secrete collagen and isolate bone matrix from extracellular space. In the matrix, alkaline phosphatase generates phosphate that combines with calcium to form mineral, liberating 8 H+ per 10 Ca+2 deposited. However, pH-dependent hydroxyapatite deposition on bone collagen had not been shown. We studied the dependency of hydroxyapatite deposition on type I collagen on pH and phosphate by surface plasmon resonance in 0–5 mM phosphate at pH 6.8–7.4. Mineral deposition saturated at <1 mM Ca2+ but was sensitive to phosphate. Mineral deposition was reversible, consistent with amorphous precipitation; stable deposition requiring EDTA removal appeared with time. At pH 6.8, little hydroxyapatite deposited on collagen; mineral accumulation increased 10-fold at pH 7.4. Previously, we showed high expression Na+/H+ exchanger (NHE) and ClC transporters in osteoblasts. We hypothesized that, in combination, these move protons across osteoblasts to the general extracellular space. We made osteoblast membrane vesicles by nitrogen cavitation and used acridine orange quenching to characterize proton transport. We found H+ transport dependent on gradients of chloride or sodium, consistent with apical osteoblast ClC family Cl−,H+ antiporters and basolateral osteoblast NHE family Na+/H+ exchangers. Little, if any, active H+ transport, supported by ATP, occurred. Major transporters include cariporide-sensitive NHE1 in basolateral membranes and ClC3 and ClC5 in apical osteoblast membranes. The mineralization inhibitor levamisole reduced bone formation and expression of alkaline phosphatase, NHE1, and ClC5. We conclude that mineral deposition in bone collagen is pH-dependent, in keeping with H+ removal by Cl−,H+ antiporters and Na+/H+-exchangers. Periodic orientation hydroxyapatite is organized on type I collagen-coiled coils.

scholarly journals Effect of protein restriction on the messenger RNA contents of bone-matrix proteins, insulin-like growth factors and insulin-like growth factor binding proteins in femur of ovariectomized rats

1996 ◽  
Vol 75 (6) ◽  
pp. 811-823 ◽  
Author(s):  
Yusuke Higashi ◽  
Asako Takenaka ◽  
Shin-Ichiro Takahashi ◽  
Tadashi Noguchi
Keyword(s):  
Dietary Protein ◽  
Type I Collagen ◽  
Control Diet ◽  
Bone Matrix ◽  
Protein Restriction ◽  
Matrix Proteins ◽  
Type I ◽  
Bone Matrix Proteins ◽  
Mrna Content ◽  
Insulin Like Growth Factors

It has been reported that loss of ovarian oestrogen after menopause or by ovariectomy causes osteoporosis. In order to elucidate the effect of dietary protein restriction on bone metabolism after ovariectomy, we fed ovariectomized young female rats on a casein-based diet (50g/kg diet (protein restriction) or 200g/kg diet (control)) for 3 weeks and measured mRNA contents of bone-matrix proteins such as osteocalcin, osteopontin and α1 type I collagen, insulin-like growth factors (IGF) and IGF-binding proteins (IGFBP) in femur. Ovariectomy decreased the weight of fat-free dry bone and increased urinary excretion of pyridinium cross-links significantly, although dietary protein restriction did not affect them. Neither ovariectomy nor protein restriction affected the content of mRNA of osteopontin and osteocalcin; however, ovariectomy increased and protein restriction extensively decreased the α1 type I collagen mRNA content in bone tissues. Ovariectomy increased IGF-I mRNA only in the rats fed on the control diet. Conversely, protein rest riction increased and ovariectomy decreased the IGF-II mRNA content in femur. Furthermore, the contents of IGFBP-2, IGFBP-4 and IGFBP-5 mRNA increased, but the content of IGFBP-3 mRNA decreased in femur of the rats fed on the protein-restricted diet. In particular, ovariectomy decreased the IGFBP-2 mRNA content in the protein-restricted rats and the IGFBP-6 mRNA content in the rats fed on the control diet. These results clearly show that the mRNA for some of the proteins which have been shown to be involved in bone formation are regulated by both quantity of dietary proteins and ovarian hormones.

scholarly journals Recruitment of osteoclast precursors by purified bone matrix constituents.

1982 ◽  
Vol 92 (1) ◽  
pp. 227-230 ◽  
Author(s):  
J D Malone ◽  
S L Teitelbaum ◽  
G L Griffin ◽  
R M Senior ◽  
A J Kahn
Keyword(s):  
Type I Collagen ◽  
Human Peripheral Blood ◽  
Bone Matrix ◽  
Chemotactic Response ◽  
Type I ◽  
Polymorphonuclear Leucocytes ◽  
Blood Monocytes ◽  
Noncollagenous Proteins ◽  
Osteoclast Precursors ◽  
Collagen Peptides

The osteoclast, the multinucleated giant cell of bone, is derived from circulating blood cells, most likely monocytes. Evidence has accrued that is consistent with the hypothesis that the recruitment of monocytes for osteoclast development occurs by chemotaxis. In the present study, we have examined the chemotactic response of human peripheral blood monocytes and related polymorphonuclear leucocytes to three constituents of bone matrix: peptides from Type I collagen, alpha 2-HS glycoprotein, and osteocalcin (bone gla protein). The latter two substances are among the major noncollagenous proteins of bone and are uniquely associated with calcified connective tissue. In chemotaxis assays using modified Boyden chambers, Type I collagen peptides, alpha 2HS glycoprotein, and osteocalcin evoke a dose-dependent chemotactic response in human monocytes. No chemotaxis is observed on PMNs despite their ontogenetic relationship to monocytes and their documented sensitivity to a broad range of other chemical substances. Our observations are consistent with the view that osteoclast precursors (monocytes) are mobilized by chemotaxis, and suggest that the chemoattractants responsible for this activity are derived from the bone matrix or, in the case of collagen and osteocalcin; directly from the osteoblasts which produce them.

Tissue Engineering of Bone by Osteoinductive Biomaterials

MRS Bulletin ◽  
1996 ◽  
Vol 21 (11) ◽  
pp. 36-39 ◽  
Author(s):  
Ugo Ripamonti ◽  
Nicolaas Duneas
Keyword(s):  
Tissue Engineering ◽  
Bone Formation ◽  
Type I Collagen ◽  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Mesenchymal Cells ◽  
Tissue Response ◽  
Type I ◽  
New Bone Formation ◽  
Demineralized Bone

Recent advances in materials science and biotechnology have given birth to the new and exciting field of tissue engineering, in which the two normally disparate fields are merging into a profitable matrimony. In particular the use of biomaterials capable of initiating new bone formation via a process called osteoinduction is leading to quantum leaps for the tissue engineering of bone.The classic work of Marshall R. Urist and A. Hari Reddi opened the field of osteoinductive biomaterials. Urist discovered that, upon implantation of devitalized, demineralized bone matrix in the muscle of experimental animals, new bone formation occurs within two weeks, a phenomenon he described as bone formation by induction. The tissue response elicited by implantation of demineralized bone matrix in muscle or under the skin includes activation and migration of undifferentiated mesenchymal cells by chemotaxis, anchoragedependent cell attachment to the matrix, mitosis and proliferation of mesenchymal cells, differentiation of cartilage, mineralization of the cartilage, vascular invasion of the cartilage, differentiation of osteoblasts and deposition of bone matrix, and finally mineralization of bone and differentiation of marrow in the newly developed ossicle.The osteoinductive ability of the extracellular matrix of bone is abolished by the dissociative extraction of the demineralized matrix, but is recovered when the extracted component, itself inactive, is reconstituted with the inactive residue—mainly insoluble collagenous bone matrix. This important experiment showed that the osteoinductive signal resides in the solubilized component but needs to be reconstituted with an appropriate carrier to restore the osteoinductive activity. In this case, the carrier is the insoluble collagenous bone matrix—mainly crosslinked type I collagen.

scholarly journals The Effect of the Combination of Vitamin K2 and Genistein, Coumestrol and Daidzein on the Osteoblast Differentiation and Bone Matrix Formation

2016 ◽  
Vol 10 (2) ◽  
pp. 12-19
Author(s):  
Sahar S. Karieb ◽  
Mohammed M. Jawad ◽  
Hanady S. Al-Shmgani ◽  
Zahraa H.M. Kadri
Keyword(s):  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Nuclear Factor Kappa B ◽  
Type I Collagen ◽  
Bone Mineralization ◽  
Bone Matrix ◽  
Vitamin K2 ◽  
Type I ◽  
Nuclear Factor ◽  
Effective Factor

Multiple studies have been reported the stimulatory effect of the combinations of nutrients factors on bone formation. One such factor is vitamin K2 which can be associated with bone protective activities. The effect of vitamin K2 alone and in combination with genistein, coumestrol and daidzein on osteoblast differentiation and mineralization were tested. Significantly, vitamin K2 increased bone mineralization in combination with genistein (10-5M), coumestrol (10-7M) and daidzein (10-5M). However, there is no additive effect of this vitamin on alkaline phosphatase (ALP) levels in osteoblasts. By contrast, vitamin K2 enhanced the stimulatory effect of type I collagen and osteocalcin expression. Vitamin K2 alone increased RUNX and OSX expression while there is no synergistic effect with tested compound; this vitamin also did not modulate nuclear factor kappa B ligand (RANKL)/ osteoprotegerin (OPG) ratio expression. These results suggested that vitamin K2 can be more effective factor in the presence of phytoestrogens on the improvement of bone formation after menopause.

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