scholarly journals Effects of matrix macromolecules on chondrocyte gene expression: synthesis of a low molecular weight collagen species by cells cultured within collagen gels.

1982 ◽  
Vol 93 (3) ◽  
pp. 767-774 ◽  
Author(s):  
G J Gibson ◽  
S L Schor ◽  
M E Grant
Keyword(s):  
Gene Expression ◽  
Molecular Weight ◽  
Three Dimensional ◽  
Molecular Size ◽  
Low Molecular Weight ◽  
Expression Data ◽  
Collagen Gels ◽  
Collagenous Matrix ◽  
Conventional Manner ◽  
Plastic Tissue Culture

Chick-embryo sternal chondrocytes have been cultured within three-dimensional collagen gels as part of a study concerned with the effects of extracellular matrix macromolecules on chondrocyte gene expression. Data are presented indicating that chondrocytes cultured within such a collagenous environment synthesize significantly more of an hitherto unidentified, low molecular weight collagen species than do cells grown on plastic tissue-culture dishes in the conventional manner. This low molecular weight collagen species contains noncollagenous domains (as indicated by its decreased molecular size after mild pepsin digestion), is distinct from the known collagen types (as judged by CNBr peptide analysis), and forms part of the insoluble collagenous matrix produced by the chondrocytes. Cells growing within the gel tend to form colonies consisting of a linear array of cells reminiscent of the cellular organization in growth cartilage.

scholarly journals Identification and partial characterization of three low-molecular-weight collagenous polypeptides synthesized by chondrocytes cultured within collagen gels in the absence and in the presence of fibronectin

1983 ◽  
Vol 211 (2) ◽  
pp. 417-426 ◽  
Author(s):  
G J Gibson ◽  
C M Kielty ◽  
C Garner ◽  
S L Schor ◽  
M E Grant
Keyword(s):  
Molecular Weight ◽  
Peptide Mapping ◽  
Three Dimensional ◽  
Low Molecular Weight ◽  
Collagen Gels ◽  
Serum Supplement ◽  
Electrophoretic Mobilities ◽  
Reducing Conditions ◽  
Interstitial Collagens

Culture of chick-embryo sternal-cartilage chondrocytes within three-dimensional collagen gels promotes the synthesis of three low-molecular-weight collagenous polypeptides. The proportions of these novel collagens synthesized and released into the medium are markedly influenced by the presence or the absence of fibronectin in the serum supplement. Chondrocytes cultured on plastic dishes appear to synthesize only small amounts of these low-molecular-weight species. The three species (designated G, H and J) were characterized with respect to the proportion of [14C]proline incorporated into each polypeptide occurring as hydroxy[14C]proline and with respect to their susceptibilities to bacterial collagenase. On the basis of their electrophoretic mobilities under reducing conditions, the G, H and J polypeptides were calculated to have Mr 59 000, 69 000 and 84 000 respectively. Chymotrypsin digestion converted the G collagen into a species containing polypeptides of Mr 45 000, whereas the H and J polypeptides yielded a single band of Mr 53 000. The H and J polypeptides were found to occur as disulphide-linked aggregates, as was the chymotrypsin-digestion product. Peptide ‘mapping’ has shown that G, H and J polypeptides show no common identity and are distinct from the known interstitial collagens. Native G collagen was digested by human collagenase to discrete products, whereas H and J chains were not cleaved under identical conditions.

Metallothionein gene expression and secretion in white adipose tissue

2000 ◽  
Vol 279 (6) ◽  
pp. R2329-R2335 ◽  
Author(s):  
Paul Trayhurn ◽  
Jacqueline S. Duncan ◽  
Anne M. Wood ◽  
John H. Beattie
Keyword(s):  
Gene Expression ◽  
Molecular Weight ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Stromal Vascular Fraction ◽  
Low Molecular Weight ◽  
Secretory Product ◽  
Mrna Levels ◽  
Gene Encoding ◽  
Adrenoceptor Agonist

White adipose tissue (WAT) has been examined to determine whether the gene encoding metallothionein (MT), a low-molecular-weight stress response protein, is expressed in the tissue and whether MT may be a secretory product of adipocytes. The MT-1 gene was expressed in epididymal WAT, with MT-1 mRNA levels being similar in lean and obese ( ob/ ob) mice. MT-1 mRNA was found in each of the main adipose tissue sites (epididymal, perirenal, omental, subcutaneous), and there was no major difference between depots. Separation of adipocytes from the stromal-vascular fraction of WAT indicated that the MT gene (MT-1 and MT-2) was expressed in adipocytes themselves. Treatment of mice with zinc had no effect on MT-1 mRNA levels in WAT, despite strong induction of MT-1 expression in the liver. MT-1 gene expression in WAT was also unaltered by fasting or norepinephrine. However, administration of a β3-adrenoceptor agonist, BRL-35153A, led to a significant increase in MT-1 mRNA. On differentiation of fibroblastic preadipocytes to adipocytes in primary culture, MT was detected in the medium, suggesting that the protein may be secreted from WAT. It is concluded that WAT may be a significant site of MT production; within adipocytes, MT could play an antioxidant role in protecting fatty acids from damage.

Localization of heparin and low-molecular-weight heparin in the rat kidney

2004 ◽  
Vol 91 (05) ◽  
pp. 927-934 ◽  
Author(s):  
Vivian Douros ◽  
Thomas Podor ◽  
Stephen Shaughnessy ◽  
Jeffrey Weitz ◽  
Edward Young
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Rat Kidney ◽  
Organic Anion ◽  
Molecular Size ◽  
Immunohistochemical Analysis ◽  
Immunoperoxidase Staining ◽  
Low Molecular Weight ◽  
Renal Tubular Cells ◽  
Renal Tubular

SummaryUnfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) are cleared, at least in part, by the kidneys through a poorly understood process. This study was undertaken to explore the mechanism of renal clearance of these drugs. Rats were given fluorescein-5-isothiocyanate (FITC)-labeled UFH or LMWH intravenously. At intervals after injection, rats were euthanized and the kidneys were harvested and subjected to immunohistochemical analysis and fluorescence microscopy. Both UFH and LMWH were localized to renal tubular cells and no immunoperoxidase staining or fluorescence was detected in glomeruli. Autoradiography demonstrated similar intracellular distribution of radio-labeled UFH suggesting that this phenomenon is independent of the method used to label heparin. Fluoresence in the tubules increased as a function of time after UFH injection, but reached a plateau after LMWH injection suggesting that the rate of renal tubular uptake depends on the molecular size of the heparin. When administered prior to FITC-labeled UFH or LMWH, probenecid, a renal organic anion inhibitor, decreased the renal tubular uptake of the heparins, whereas cimetidine, a renal organic cation inhibitor, had no effect. These findings suggest that renal excretion of UFH and LMWH primarily reflects tubular uptake via an organic anion transport mechanism.

Calcium enhances gene expression when using low molecular weight poly-l-lysine delivery vehicles

2018 ◽  
Vol 547 (1-2) ◽  
pp. 274-281 ◽  
Author(s):  
Sheng-Xue Xie ◽  
Abdulgader A. Baoum ◽  
Nabil A. Alhakamy ◽  
Cory J. Berkland
Keyword(s):  
Gene Expression ◽  
Molecular Weight ◽  
Low Molecular Weight ◽  
Delivery Vehicles

A diffusion wake model for tracer ultrastructure-permeability studies in microvessels

1995 ◽  
Vol 269 (6) ◽  
pp. H2124-H2140 ◽  
Author(s):  
B. M. Fu ◽  
F. E. Curry ◽  
S. Weinbaum
Keyword(s):  
Molecular Weight ◽  
Three Dimensional ◽  
Threshold Concentration ◽  
Time Dependent ◽  
Surrounding Tissue ◽  
Low Molecular Weight ◽  
Electron Microscopic ◽  
Small Pore ◽  
Tissue Space ◽  
Transvascular Exchange

We developed a time-dependent diffusion model for analyzing the concentration profiles of low-molecular-weight tracers in the interendothelial clefts of the capillary wall that takes into account the three-dimensional time-dependent filling of the surrounding tissue space. The model provides a connecting link between two methods to investigate transvascular exchange: electron-microscopic experiments to study the time-dependent wake formed by low-molecular-weight tracers (such as lanthanum nitrate) on the tissue side of the junction strand discontinuities in the interendothelial cleft of frog mesentery capillaries (R. H. Adamson and C. C. Michel. J. Physiol. Lond. 466: 303-327, 1993) and confocal-microscopic experiments to measure the spread of low-molecular-weight fluorescent tracers in the tissue space surrounding these microvessels (R. H. Adamson, J. F. Lenz, and F. E. Curry, Microcirculation 1: 251-265, 1994). We show that the interpretation of the presence of tracer as an all-or-none indication of a pathway across the junctional strand is likely to be incorrect for small solutes. Large-pore pathways, in which the local tracer flux densities are high, reach a threshold concentration for detection and are likely to be detected after relatively short perfusion times, whereas distributed small-pore pathways may not be detected until the tissue concentrations surrounding the entire vessel approach threshold concentrations. The analysis using this approach supports the hypothesis advanced by Fu et al. (J. Biomech. Eng. 116: 502-513, 1994) that the principal pathways for water and solutes of < 1.0 nm diameter across the interendothelial cleft may be different and suggests new experiments to test this hypothesis.

scholarly journals Thrombospondin gene expression by endothelial cells in culture is modulated by cell proliferation, cell shape and the substratum

1990 ◽  
Vol 268 (1) ◽  
pp. 225-230 ◽  
Author(s):  
A E Canfield ◽  
R P Boot-Handford ◽  
A M Schor
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Endothelial Cells ◽  
Cell Shape ◽  
Type I Collagen ◽  
Three Dimensional ◽  
Type I ◽  
Mrna Levels ◽  
Collagen Gels ◽  
Cells Cultured

Endothelial cells plated on the surface of a two-dimensional substratum (gelatin-coated dishes, dishes coated with native type I collagen or collagen gels) form a cobblestone monolayer at confluence, whereas cells plated within a three-dimensional gel matrix elongate into a sprouting morphology and self-associate into tube-like structures. In this study, we have compared the synthesis of thrombospondin by quiescent endothelial cells displaying (a) the same morphological phenotype (cobblestone) on different substrata (gelatin and collagen) and (b) different morphological phenotypes (cobblestone and sprouting) on the same substratum (collagen). We demonstrate that thrombospondin is a major biosynthetic product of confluent, quiescent cells cultured on dishes coated with either gelatin or collagen, and that the synthesis of this protein is markedly decreased when cells are plated on or in three-dimensional collagen gels. Moreover, we demonstrate that cells plated in gel (sprouting) secrete less thrombospondin than do cells plated on the gel surface (cobblestone). The regulation of thrombospondin synthesis is reversible and occurs at the level of transcription, as steady-state mRNA levels for thrombospondin decrease in a manner comparable with the levels of protein secreted by these cells. We also show that mRNA levels for laminin B2 chains are increased when cells are cultured on and in collagen gels compared with on gelatin-coated dishes, suggesting that the syntheses of thrombospondin and laminin are regulated by different mechanisms. When cells are cultured on gelatin- or collagen-coated dishes, thrombospondin gene expression is directly proportional to the proliferative state of the cultures. By contrast, the synthesis of thrombospondin by cells cultured on collagen gels remains at equally low levels whether they are labelled when they are sparse and rapidly proliferating or when they are confluent and quiescent. Fibronectin synthesis was found to increase with increasing confluency of the cells plated on all three substrata. These results demonstrate that thrombospondin gene expression is modulated by cell shape, cell proliferation and the nature of the substratum used for cell culture.

Three dimensional heteroatom-doped carbon composite film for flexible solid-state supercapacitors

RSC Advances ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 4483-4489 ◽  
Author(s):  
Ben-Xue Zou ◽  
You Gao ◽  
Bo Liu ◽  
Yongpeng Yu ◽  
Yanhua Lu
Keyword(s):  
Molecular Weight ◽  
Solid State ◽  
Composite Film ◽  
Active Carbon ◽  
Resin Composite ◽  
Three Dimensional ◽  
Carbon Composite ◽  
Low Molecular Weight ◽  
Supercapacitor Electrode ◽  
Flexible Supercapacitor

Three dimensional (3D) heteroatom-doped active carbon as a flexible supercapacitor electrode is explored with a starting material of silkworm fibers and low molecular weight phenol resin composite.

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