Article (Scientific journals)
Cdc42 downregulates MMP-1 expression by inhibiting the ERK1/2 pathway.
Deroanne, Christophe; Hamelryckx, Delphine; Ho, Thi Thanh Giang et al.
2005In Journal of Cell Science, 118 (Pt 6), p. 1173-83
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Keywords :
Blotting, Western; Cell Adhesion; Cell Line, Tumor; RhoA; Rac1; Down-Regulation; Enzyme Inhibitors/pharmacology; MMP-1; Cdc42; GTP Phosphohydrolases/metabolism; Gene Silencing; SiRNA
Abstract :
[en] The small GTPases of the Rho family are key intermediates in cellular signalling triggered by activated cell-adhesion receptors. In this study, we took advantage of RNA interference (RNAi) using small interfering RNAs (siRNAs) to define the roles of the best-characterized members of the RhoGTPase family, RhoA, Rac1 and Cdc42, in the control of MMP-1, MMP-2 and type-I-collagen expression in normal human skin fibroblasts (HSFs). A specific and long-lasting repression, up to 7 days after transfection, of the three GTPases was achieved by transient transfection of specific siRNA. The silencing of Cdc42, but not that of RhoA or Rac1, induced a 15-fold increase in MMP-1 secretion. This upregulation was confirmed at the mRNA level and observed with two different siRNAs targeting Cdc42. Such a regulation was also observed in various human cell lines and was rescued by re-expressing wild-type Cdc42 encoded by a construct bearing silent mutations impeding its recognition by the siRNA. By contrast, MMP-2 and type-I-collagen expression was not affected by the individual silencing of each Rho GTPase. Cytokine protein array, enzyme-linked immunosorbent assays and reverse-transcription PCR measurements revealed that ablation of Cdc42 induced an overexpression of interleukin 8 and MCP-1. Although these cytokines are known to induce the expression of MMP-1, we showed that they were not involved in the Cdc42-mediated upregulation of MMP-1. Silencing of Cdc42 also induced an increased phosphorylation of ERK1/2 and p38 MAP kinase. The use of chemical inhibitors on Cdc42-ablated cells revealed that the upregulation of MMP-1 is dependent on the ERK1/2 pathways, whereas the p38 MAP kinase pathway displayed an inhibitory role. Simultaneous knock-down of two or three Rho GTPases allowed us to demonstrate that the RhoA-ROCK pathway was not involved in this regulation but that the silencing of Rac1 reduced the effect of Cdc42 suppression. These data suggest that, in vivo, when cell/extracellular-matrix interactions via integrins induce cytoskeleton organization, MMP-1 expression is maintained at a low level by Cdc42 via a repression of the Rac1 and ERK1/2 pathways. Therefore, Cdc42 contributes to ECM homeostasis and connective tissue integrity.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Deroanne, Christophe ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Laboratoire de Biologie des tissus conjonctifs
Hamelryckx, Delphine;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Laboratoire des tissus conjonctifs
Ho, Thi Thanh Giang ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Laboratoire des tissus conjonctifs
Lambert, Charles ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Protéines et glycoprot. de matr.extracell. et membran.basal.
Catroux, Philippe;  L'OREAL > Research and Development
Lapiere, Charles M
Nusgens, Betty ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Laboratoire de Biologie des Tissus Conjonctifs
Language :
English
Title :
Cdc42 downregulates MMP-1 expression by inhibiting the ERK1/2 pathway.
Publication date :
2005
Journal title :
Journal of Cell Science
ISSN :
0021-9533
eISSN :
1477-9137
Publisher :
Company of Biologists, Cambridge, United Kingdom
Volume :
118
Issue :
Pt 6
Pages :
1173-83
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 22 July 2009

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