Hydroxyapatite formation in a dynamic collagen gel system: effects of type I collagen, lipids, and proteoglycans

1989 ◽  
Vol 93 (4) ◽  
pp. 1628-1633 ◽  
Author(s):  
Adele L. Boskey
Keyword(s):  
Type I Collagen ◽  
Collagen Gel ◽  
Type I ◽  
Hydroxyapatite Formation ◽  
Gel System

scholarly journals Inhibition of hydroxyapatite formation in collagen gels by chondroitin sulphate

1985 ◽  
Vol 228 (2) ◽  
pp. 463-469 ◽  
Author(s):  
G K Hunter ◽  
B L Allen ◽  
M D Grynpas ◽  
P T Cheng
Keyword(s):  
Type I Collagen ◽  
Chondroitin Sulphate ◽  
Collagen Gel ◽  
Calcium Pyrophosphate ◽  
Molar Ratio ◽  
Crystal Formation ◽  
Type I ◽  
Collagen Gels ◽  
High Concentrations ◽  
Hydroxyapatite Formation

Crystal growth in native collagen gels has been used to determine the role of extracellular matrix macromolecules in biological calcification phenomena. In this system, type I collagen gels containing sodium phosphate and buffered at pH 7.4 are overlayed with a solution containing CaCl2. Crystals form in the collagen gel adjacent to the gel-solution interface. Conditions were determined which permit the growth of crystals of hydroxyapatite [Ca10(PO4)6(OH)2]. At a Ca/P molar ratio of 2:1, the minimum concentrations of calcium and phosphate necessary for precipitation of hydroxyapatite are 10 mM and 5 mM, respectively. Under these conditions, precipitation is initiated at 18-24h, and is maximal between 24h and 6 days. Addition of high concentrations of chondroitin 4-sulphate inhibits the formation of hydroxyapatite in collagen gels; initiation of precipitation is delayed, and the final (equilibrium) amount of precipitation is decreased. Inhibition of hydroxyapatite formation requires concentrations of chondroitin sulphate higher than those required to inhibit calcium pyrophosphate crystal formation.

scholarly journals Targeting lncRNA H19/miR-29b/COL1A1 Axis Impedes Myofibroblast Activities of Precancerous Oral Submucous Fibrosis

2021 ◽  
Vol 22 (4) ◽  
pp. 2216
Author(s):  
Cheng-Chia Yu ◽  
Yi-Wen Liao ◽  
Pei-Ling Hsieh ◽  
Yu-Chao Chang
Keyword(s):  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Oral Submucous Fibrosis ◽  
Ectopic Expression ◽  
Collagen Gel ◽  
Type I ◽  
Migration Ability ◽  
Potentially Malignant ◽  
Submucous Fibrosis

Oral submucous fibrosis (OSF) is known as a potentially malignant disorder, which may result from chemical irritation due to areca nuts (such as arecoline). Emerging evidence suggests that fibrogenesis and carcinogenesis are regulated by the interaction of long noncoding RNAs (lncRNAs) and microRNAs. Among these regulators, profibrotic lncRNA H19 has been found to be overexpressed in several fibrosis diseases. Here, we examined the expression of H19 in OSF specimens and its functional role in fibrotic buccal mucosal fibroblasts (fBMFs). Our results indicate that the aberrantly overexpressed H19 contributed to higher myofibroblast activities, such as collagen gel contractility and migration ability. We also demonstrated that H19 interacted with miR-29b, which suppressed the direct binding of miR-29b to the 3′-untranslated region of type I collagen (COL1A1). We showed that ectopic expression of miR-29b ameliorated various myofibroblast phenotypes and the expression of α-smooth muscle actin (α-SMA), COL1A1, and fibronectin (FN1) in fBMFs. In OSF tissues, we found that the expression of miR-29b was downregulated and there was a negative correlation between miR-29b and these fibrosis markers. Lastly, we demonstrate that arecoline stimulated the upregulation of H19 through the transforming growth factor (TGF)-β pathway. Altogether, this study suggests that increased TGF-β secretion following areca nut chewing may induce the upregulation of H19, which serves as a natural sponge for miR-29b and impedes its antifibrotic effects.

Apical beta 1 integrin in polarized MDCK cells mediates tubulocyst formation in response to type I collagen overlay

1996 ◽  
Vol 109 (7) ◽  
pp. 1875-1889 ◽  
Author(s):  
A. Zuk ◽  
K.S. Matlin
Keyword(s):  
Plasma Membranes ◽  
Type I Collagen ◽  
Mdck Cells ◽  
Basolateral Membrane ◽  
Collagen Gel ◽  
Type I ◽  
Membrane Markers ◽  
Polarized Epithelia ◽  
Beta 1 Integrin ◽  
Type I Collagen Gel

A number of epithelia form tubulocysts in vitro when overlaid with type I collagen gel. Because collagen receptors are generally believed to be expressed on the basolateral domain, the mechanism by which collagen elicits this morphogenetic response from the apical surface is unclear. To investigate the role of beta 1 integrins, the major receptor family for collagen, in this process, we overlaid polarized monolayers of MDCK II cells grown on permeable supports with type I collagen gel and correlated integrin polarity with the polarity of other apical and basolateral membrane markers during tubulocyst formation. Polarized monolayers of one clone of MDCK II cells, referred to as Heidelberg MDCK, initially respond to collagen overlay by stratifying; within 48 hours, lumena develop between the cell layers giving rise to tubulocysts. Tight junctions remain intact during tubulocyst formation because transepithelial electrical resistance does not significantly change. Major alterations are observed, however, in the expression and localization of apical and basolateral membrane markers. beta 1 integrins are necessary for tubulocyst morphogenesis because a function-blocking antibody administered to the apical pole of the cells completely inhibits the formation of these structures. To determine how apical-cell collagen interactions elicit tubulocyst formation, we examined whether beta 1 integrins are mobilized to apical plasma membranes in response to collagen overlay. We found that in the absence of collagen, polarized monolayers of Heidelberg MDCK cells endogenously express on apical plasma membranes a small pool of the beta 1 family, including alpha 2 beta 1 and alpha 3 beta 1. Collagen overlay does not mobilize additional beta 1 integrins to apical domains. If beta 1 integrins are not already apically expressed, as in the C6 MDCK cell line (Schoenenberger et al. (1994) J. Cell Biol. 107, 527–541), beta 1 integrins are not directed apically and tubulocysts do not develop in response to collagen. Thus, interaction of beta 1 integrin pre-existing on apical plasma membranes of polarized epithelia with type I collagen gel is the mechanism by which apical application of collagen elicits the formation of tubulocysts. Depolarized integrins on apical plasma membranes of polarized epithelia may be relevant to the pathogenesis of disease and injury.

scholarly journals EFFECT OF COLLAGEN I GEL ON APOPTOSIS OF RAT HEPATIC STELLATE CELLS

2013 ◽  
Vol 56 (2) ◽  
pp. 73-79
Author(s):  
Lenka Bittnerová ◽  
Alena Jiroutová ◽  
Emil Rudolf ◽  
Martina Řezáčová ◽  
Jiří Kanta
Keyword(s):  
Hepatic Stellate Cells ◽  
Type I Collagen ◽  
Collagen Gel ◽  
Stellate Cells ◽  
Type I ◽  
Function Type ◽  
Fibrotic Liver ◽  
Normal Rat ◽  
And Function

Activated hepatic stellate cells (HSC) are a major source of fibrous proteins in cirrhotic liver. Inducing or accelerating their apoptosis is a potential way of liver fibrosis treatment. Extracellular matrix (ECM) surrounding cells in tissue affects their differentiation, migration, proliferation and function. Type I collagen is the main ECM component in fibrotic liver. We have examined how this protein modifies apoptosis of normal rat HSC induced by gliotoxin, cycloheximide and cytochalasin D in vitro and spontaneous apoptosis of HSC isolated from CCl4-damaged liver. We have found that type I collagen gel enhances HSC apoptosis regardless of the agent triggering this process.

Cytoskeleton and thyroglobulin expression change during transformation of thyroid epithelium to mesenchyme-like cells

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 605-622 ◽  
Author(s):  
G. Greenburg ◽  
E.D. Hay
Keyword(s):  
Type I Collagen ◽  
Collagen Gel ◽  
Type I ◽  
Basal Cells ◽  
Collagen Gels ◽  
Expression Change ◽  
Cell Functions ◽  
The Matrix ◽  
3D Matrix ◽  
Mesenchymal Transformation

In considering the mechanism of transformation of epithelium to mesenchyme in the embryo, it is generally assumed that the ability to give rise to fibroblast-like cells is lost as epithelia mature. We reported previously that a definitive embryonic epithelium, that of the anterior lens, gives rise to freely migrating mesenchyme-like cells when suspended in type I collagen matrices. Here, we show that a highly differentiated epithelium that expresses cytokeratin changes to a vimentin cytoskeleton and loses thyroglobulin during epithelial-mesenchymal transformation induced by suspension in collagen gel. Using dispase and collagenase, we isolated adult thyroid follicles devoid of basal lamina and mesenchyme, and we suspended the follicles in 3D collagen gels. Cells bordering the follicle lumen retain epithelial polarity and thyroid phenotype, but basal cell surface organization is soon modified as a result of tissue multilayering and elongation of basal cells into the collagenous matrix. Cytodifferentiation, determined by thyroglobulin immunoreactivity, is lost as the basal epithelial cells move into the matrix after 3–4 days in collagen. By TEM, it can be seen that the elongating cells acquire pseudopodia, filopodia and mesenchyme-like nuclei and RER. Immunofluorescence examination of intermediate filaments showed that freshly isolated follicles and follicles cultured on planar substrata react only with anticytokeratin. However, all of the mesenchyme-like cells express vimentin and they gradually lose cytokeratin. These results suggest that vimentin may be necessary for cell functions associated with migration within a 3D matrix. The mesenchymal cells do not revert to epithelium when grown on planar substrata and the transformation of epithelium to mesenchyme-like cells does not occur within basement membrane gels. The results are relevant to our understanding of the initiation of epithelial-mesenchymal transformation in the embryo and the genetic mechanisms controlling cell shape, polarity and cytoskeletal phenotype.

A Continuous-Discrete Finite Element Model of Angiogenesis That Couples Vessel Growth With Matrix Deformation

2013 ◽  
Author(s):  
Lowell T. Edgar ◽  
Steve A. Maas ◽  
James E. Guilkey ◽  
Jeffrey A. Weiss
Keyword(s):  
Type I Collagen ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Element Model ◽  
Fibrillar Structure ◽  
Type I ◽  
Major Pathway ◽  
Vessel Growth ◽  
Discrete Finite Element

Recent developments in tissue engineering have created demand for the ability to create microvascular networks with specific topologies in vitro. During angiogenesis, sprouting endothelial cells apply traction forces and migrate along components of the extracellular matrix (ECM), resulting in neovessel elongation [1]. The fibrillar structure of the ECM serves as the major pathway for mechanotransduction between contact-dependent cells. Using a three-dimensional (3D) organ culture model of microvessel fragments within a type-I collagen gel, we have shown that subjecting the culture to different boundary conditions during angiogenesis can lead to drastically different vascular topologies [2]. Fragments cultured in a rectangular gel that were free to contract grew into a randomly oriented network [3, 4]. When the long-axis of the gel was constrained as to prevent contraction, microvessels and collagen fibers were found aligned along the constrained axis (Fig. 1) [4].

scholarly journals Endothelial cell crosstalk improves browning but hinders white adipocyte maturation in 3D engineered adipose tissue

2020 ◽  
Vol 12 (4) ◽  
pp. 81-89
Author(s):  
Jennifer H Hammel ◽  
Evangelia Bellas
Keyword(s):  
Endothelial Cells ◽  
Adipose Tissue ◽  
Type I Collagen ◽  
Network Formation ◽  
Uncoupling Protein ◽  
Collagen Gel ◽  
Cell Types ◽  
Vascular Network ◽  
Type I ◽  
White Adipocyte

Abstract Central to the development of adipose tissue (AT) engineered models is the supporting vasculature. It is a key part of AT function and long-term maintenance, but the crosstalk between adipocytes and endothelial cells is not well understood. Here, we directly co-culture the two cell types at varying ratios in a 3D Type I collagen gel. Constructs were evaluated for adipocyte maturation and function and vascular network organization. Further, these constructs were treated with forskolin, a beta-adrenergic agonist, to stimulate lipolysis and browning. Adipocytes in co-cultures were found to be less mature than an adipocyte-only control, shown by smaller lipid droplets and downregulation of key adipocyte-related genes. The most extensive vascular network formation was found in the 1:1 co-culture, supported by vascular endothelial growth factor (VEGF) upregulation. After forskolin treatment, the presence of endothelial cells was shown to upregulate PPAR coactivator 1 alpha (PGC-1α) and leptin, but not uncoupling protein 1 (UCP1), suggesting a specific crosstalk that enhances early stages of browning.

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