title: Modulation by hypergravity of extracellular matrix macromolecules in in vitro human dermal fibroblasts.
abstract: In vitro human dermal fibroblasts were submitted to normal gravity (1 g) or to chronic hypergravity (20 g) over a period of 8 days. Changes in organization of extracellular matrix molecules were seen by indirect immunofluorescence. In the fibronectin layer, bundles of fibrils were gathered together leading to a disorganisation of the normal parallel pattern of fibers seen in control cultures. Type I collagen fibrils appeared with wooly outlines in controls whereas thick fibers were closely packed in 20-g cultures. A moderate increase of type III collagen fibril density was observed. No elastic fibers were seen in control or in 20-g cultures. In the culture medium, the release of soluble elastin (ELISA) and type I and III collagens (RIA) was undisturbed. Assays of enzymes involved in the remodeling of extracellular matrix showed an increase of cellular elastase activity (10%) and a decrease of the spontaneously active collagenase. Nevertheless, the total collagenase activity, (activated by trypsin), was increased by up to 30%. These data show a significant rise of the latent collagenase activity and suggest that release of the tissue inhibitor of metalloproteinase (TIMP1) was enhanced by hypergravity.
mesh_terms: D000293:Adolescent; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D003470:Culture Media; D004549:Elastin / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism* / Q000648:ultrastructure; D019084:Fluorescent Antibody Technique, Indirect; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D018471:Hypergravity; D008666:Metalloendopeptidases / Q000378:metabolism; D010196:Pancreatic Elastase / Q000378:metabolism; D011480:Protease Inhibitors / Q000378:metabolism; D019714:Tissue Inhibitor of Metalloproteinases; D014357:Trypsin / Q000494:pharmacology
chemical_list: D003470:Culture Media; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D011480:Protease Inhibitors; D019714:Tissue Inhibitor of Metalloproteinases; D003094:Collagen; D004549:Elastin; D010196:Pancreatic Elastase; D014357:Trypsin; D008666:Metalloendopeptidases