An Interleukin-1 Loop Is Induced in Human Skin Fibroblasts upon Stress Relaxation in a Three-dimensional Collagen Gel but Is Not Involved in the Up-regulation of Matrix Metalloproteinase 1

Abstract

The integrin-mediated stress relaxation as it occurs in a retracting three-dimensional collagen gel (RCG) is accompanied by a large up-regulation of the interstitial collagenase, matrix metalloproteinase 1 ((MMP Integrins are transmembrane heterodimeric proteins providing a structural link between the extracellular matrix and the cytoskeleton. They are responsible for the transduction to the cell of information arising from specific sequences within the macromolecules and/or triggered by the mechanical properties of their polymers. Both messages, chemical and/or mechanical, are responsible for controlling signaling processes that involve assembly of multiple proteins in the focal adhesion plaque, organization of cytoskeletal actin polymers, and their anchorage to the cell membrane, protein phosphorylation and activation of signaling cascades leading to regulation of genes expression through several potential pathways (1). The interactions of cells with the extracellular matrix are essential in many biological and pathophysiological processes as embryonic development, wound healing, fibrosis, tumor invasion, and metastasis.-Most of the integrin-mediated regulations and signaling by mechanical forces have been investigated in cells under stress (1, 2). Much less is known about the messages that the cells receive and the signaling that is triggered when stress is released. This event is relevant to investigate since it participates in physiological and pathological processes observed during extracellular matrix degradation in remodeling, cancer and inflammatory diseases, mammary epithelium differentiation (3), and osteoporosis induced by suppression of muscular activity or in weightlessness conditions (4). Furthermore, reduced mechanical tension is actually regarded as a signal inducing programmed cell death (5, 6)The culture of cells within a free floating gel of collagen polymers offers a model of integrin-mediated stress relaxation. When fibroblasts are cultured in such a gel, they attach to the fibers and retract the gel. According to the "tensegrity" concept proposed by Ingber (7), the dissipation of mechanical tension upon retraction of the malleable collagen gel results in alteration of the dynamic balance of the cytoskeleton. It is visualized by the reorganization of the actin network with the disappearance of the stress fibers (8) and the assembly of actin clusters along the cell periphery (9). This process is accompanied by a profound reprogramming of the cell phenotype. We, and others, have demonstrated an arrest of cell division, an extensive reduction of collagen and other structural macromolecules expression (10, 11), whereas a large up-regulation of interstitial collagenase (MMP-1, 1 EC 3.4.24.7) was observed (12, 13). It was recently demonstrated that ␣ 2 ␤ 1 is the major determinant of the contraction of the collagen gel (14, 15) and the mediator of the regulation of the MMP-1 gene in fibroblasts cultured in a retracting collagen gel while ␣ 1 ␤ 1 mediates the COL1A1 gene down-regulation (16,17).MM...

Cloning and Characterization of ADAMTS-14, a Novel ADAMTS Displaying High Homology with ADAMTS-2 and ADAMTS-3

“…Results are expressed as a ratio of the values determined for treated on untreated cells. Modulation of MMP1 expression measured in the different conditions was in good agreement with previous reports (22,23) confirming the efficiency of cell treatment. At the opposite, none of the five treatments was able to significantly modify the ADAMTS14 overall expression (Fig.…”

Laminin α3 LG4 Module Induces Matrix Metalloproteinase-1 through Mitogen-activated Protein Kinase Signaling

“…On the contrary, in fibroblasts A3G756 could up-regulate MMP-1 expression in the presence of an even higher concentration of IL-1RA (1.0 g/ml) (Fig. 2B), which is the concentration used by other groups for blocking the IL-1 autocrine loop in dermal fibroblasts (33,34). Taken together, the results show that the IL-1␤ autocrine loop is an essential pathway for A3G756-mediated induction of MMP-1 in keratinocytes, but it is not necessary in fibroblasts, even though A3G756 was able to induce IL-1␤ gene expression (Fig.…”

Distinct pathways in the over-expression of matrix metalloproteinases in human fibroblasts by relaxation of mechanical tension

“…Two days of culture was selected on the basis of previous work showing that the expression of MMP-1 in CD-treated monolayer and in RCG was largely increased after 48 h (Lambert et al, 1992(Lambert et al, , 1998. One typical set of electrophoretic patterns of the amplification products of the mRNA, and the mssRNA for the investigated MMPs, is illustrated in Fig.…”

“…It results in the phenotype displayed by fibroblasts in monolayer on a rigid culture dish, with a dense network of actin stress fibers anchored to focal adhesions. Decreasing the tensional force by disruption of the cytoskeleton by cytochalasin D (CD), or by culturing fibroblasts in a floating freely retracting collagen gel (RCG), produces drastic changes, expressed by: a decrease of the multiplication rate; commitment to apoptosis; and regulated expression of specific genes (Nusgens et al, 1984;Unemori and Werb, 1986;Mauch et al, 1988Mauch et al, , 1989Lambert et al, 1992Lambert et al, , 1998Fluck et al, 1998). Notably, a large up-regulation of MMP-1 is observed both at the protein and mRNA levels.…”

“…The signaling pathway operating in the RCG-induced MMP-1 over-expression is mediated through the a 2 β 1 inte-grin (Langholz et al, 1995;Riikonen et al, 1995), and involves the activation of tyrosine kinases and the expression or activation of transacting factors (Broberg and Heino, 1996;Lambert et al, 1998). The over-expression of MMP-1 induced by CD further depends on the activity of TPA-dependent protein kinase C (PKC) isoforms while that in RCG does not (Lambert et al, 1998). MMP-13 is also over-expressed in RCG.…”