Regulation of collagen prolyl 4-hydroxylase and matrix metalloproteinases in fibrosarcoma cells by hypoxia.
The cellular response to hypoxia is characterized by an enhanced deposition of extracellular matrix (ECM) components, mainly collagens. Collagen homeostasis is determined by the rate of synthesis and degradation. In this study, we investigated the synthesis of enzymes of collagen metabolism like collagen prolyl 4-hydroxylase (P4H), matrix metalloproteinases (MMP-2 and MMP-9) and their regulatory factors MT1-MMP, TIMP-1 and TIMP-2 in HT1080 fibroblasts under the influence of hypoxia. The results indicate that hypoxia affects collagen homeostasis in a biphasic manner concerning basic mechanisms of gene expression. P4H-alpha subunits are up-regulated at the transcriptional and translational level, whereas the beta-subunit is not susceptible to hypoxia. MMP-9 is primarily regulated at the transcriptional and translational level, whereas MMP-2 is mainly controlled by proteolytic activation of the proenzyme. Our results suggest that short-term hypoxia facilitates fibrosis in HT1080 cells by activation of P4H-alpha expression and inhibition of the synthesis of MMPs. Under long-term hypoxia, however, anti-fibrotic mechanisms prevail. Although P4H-alpha expression sustains at a high level, collagenolytic activities dominate by abolishing inhibition of synthesis and activity of MMPs.
Fähling
Michael
M
Institut für Vegetative Physiologie, Charité, Universitätsmedizin Berlin, Tucholskystr. 2, 10117 Berlin, Germany.
Perlewitz
Andrea
A
Doller
Anke
A
Thiele
Bernd-Joachim
BJ
D015153:Blotting, Western; D015687:Cell Hypoxia / Q000502:physiology*; D002460:Cell Line; D003094:Collagen / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix / Q000378:metabolism; D005354:Fibrosarcoma / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis; D020782:Matrix Metalloproteinases / Q000096:biosynthesis*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000378:metabolism; D011393:Procollagen-Proline Dioxygenase / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D013997:Time Factors; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D015854:Up-Regulation
D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D003094:Collagen; D011393:Procollagen-Proline Dioxygenase; D020782:Matrix Metalloproteinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9