Constitutive collagenase-1 synthesis through MAPK pathways is mediated, in part, by endogenous IL-1α during fibrotic repair in corneal stroma (original) (raw)
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Matrix, 1990
The aim of the present study was to determine whether interleukin 1a (11-1), a cytokine known to have a stimulatory effect on collagenase production, also influences the phagocytosis and intracellular digestion of collagen fibrils by fibroblasts. Mouse long bones and calvariae both with surrounding periosteum were cultured for 24 or 48 hours in media containing varying concentrations of the cytokine. The periostea were subjected to morphometric analysis in order to assess the volume density of phagocytosed collagen fibrils in fibroblasts. The results indicated that neither in calvarial nor in long bone periosteum the uptake and intracellular degradation of collagen by fibroblasts was influenced by 11-1. However, between both tissues the amount of collagen phagocytosed differed considerably. It appeared that within 48 hours periosteal fibroblasts of calvariae ingested at least three times more fibrillar collagen than those of long bone periosteum. This finding suggests intrinsic differences between these connective tissues as to the phagocytic behaviour of the fibroblasts.
Nucleic Acids Research, 1994
Interleukin-1 B is believed to contribute to the pathophysiology of rheumatoid arthritis by activating collagenase gene expression. We have used a cell culture model of rabbit synovial fibroblasts to examine the molecular mechanisms of IL-1,8-mediated collagenase gene expression. Stimulation of rabbit synovial fibroblasts with 10 ng/ml recombinant human IL-1B resulted in a 20-fold increase in collagenase mRNA by 12 h. Transient transfection studies using collagenase promoter -CAT constructs demonstrated that proximal sequences responded poorly to IL-13,S possibly due to insufficient activation of AP-1 by this cytokine. More distal sequences were required for IL-1,B responsiveness, with a 4700 bp construct showing -5-fold induction above control. To examine posttranscriptional mechanisms, transcript from a human collagenase cDNA was constitutively produced by the simian virus 40 early promoter. IL-1(3 stabilized the constitutively expressed human transcript. Furthermore, mutation of the ATTTA motifs in the 3' untranslated region of the human gene also stabilized the transcript. Finally, the rabbit coliagenase 3' untranslated region destabilized a constitutively transcribed chloramphenicol acetyltransferase transcript. These data Indicate that in addition to activating transcription, IL-1 B increases coliagenase transcript stability by reversing the destabilizing effects of sequences in the 3' untranslated region.
Journal of Biological Chemistry, 1998
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-1), EC 3.4.24.7), regulated notably by interleukin-1 (IL-1), phorbol esters, and cytoskeleton-disrupting drugs as cytochalasin D (CD). The repression of MMP-1 up-regulation in RCG by cycloheximide suggested the participation in the regulation process of a de novo synthesized intermediary component. We demonstrate here that culture of human skin fibroblasts in RCG or in CD-and 12-O-tetradecanoylphorbol-13-acetate (TPA)treated monolayers resulted in the activation of an IL-1 autocrine feedback loop that was switched off by the naturally occurring IL-1 receptor antagonist (IL-1RA), a blocker of the common IL-1 receptor. The IL-1RA did not suppress the MMP-1 up-regulation induced in RCG nor in CD-treated cells, indicating that the up-regulation of MMP-1 and the IL-1 autocrine loop occurred in an independent way, while the TPA-induced MMP-1 expression was suppressed by the receptor antagonist. The RCG-as well as the TPA-, IL-1-, and CD-induced up-regulation of both MMP-1 and IL-1 was totally suppressed by protein tyrosine kinases inhibitors. In contrast bisindoylmaleimide, at a concentration (5 M) that inhibits the TPA-induced protein kinase C activity, suppressed the CD-induced MMP-1 expression but did not or barely altered that induced in RCG or by IL-1. None of the other tested inhibitors of a variety of signaling pathways including those used by integrins was able to suppress the RCG or CD-induced MMP-1. These results point to a potent regulation of MMP-1 by mechanical stress relaxation, a process depending on de novo protein synthesis and occurring independently of the activation of an IL-1 autocrine feedback loop.
Interleukin-1 increases collagen production and mRNA levels in cultured skin fibroblasts
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 1987
In the present study we show that highly purified human interleukin-1 increases collagen production nearly 2-fold and mRNA levels of type I and III collagen over 2.5-fold in cultured normal human dermal fibroblasts. To minimize the effects of transient prostaglanding E 2 production in fibroblasts treated with interleukin-1, the cell cultures were preincubated for 24 h before these measurements were made. The effects of interleukin-I were also tested on scleroderma fibroblasts exhibiting increased collagen production. Although collagen synthesis was stimulated by interleukin-1 to some degree, the cells grown from both affected and unaffected skin areas were found to be relatively unresponsive to the effects of interleukin-l, suggesting a role for this monokine in the earlier stages of the disease process. The results also suggest that interleukin-1 has a role in stimulation of collagen synthesis under certain normal and pathological conditions in addition to stimulating fibroblast proliferation.
Investigative Opthalmology & Visual Science, 2008
PURPOSE. Corneal ulcer results from excessive collagen degradation in the corneal stroma. Interleukin (IL)-1 promotes this process by activating signaling molecules that include nuclear factor (NF)-B and stimulating the synthesis of matrix metalloproteinases (MMPs) in corneal fibroblasts. NF-B activation is mediated by phosphorylation of the inhibitor IB by IB kinase (IKK)-2 and consequent IB degradation. The authors investigated the effects of the IKK-2 inhibitor [5-(p-fluorophenyl)-2ureido]thiophene-3-carboxamide (TPCA-1) on collagen degradation by corneal fibroblasts. METHODS. Rabbit corneal fibroblasts were cultured in threedimensional collagen gels. Collagen degradation was evaluated by spectrophotometric quantitation of hydroxyproline in culture supernatants subjected to acid-heat hydrolysis. Expression of MMPs was evaluated by immunoblot analysis, gelatin zymography, and real-time reverse transcription polymerase chain reaction analysis. The phosphorylation and degradation of IB␣ and the subcellular localization of NF-B were examined by immunoblot and immunofluorescence analyses, respectively. RESULTS. IL-1-induced collagen degradation by corneal fibroblasts was inhibited by TPCA-1 in a concentration-and timedependent manner. TPCA-1 inhibited the IL-1-induced expression of MMP-1,-3, and-9 in these cells at both the mRNA and protein levels and the IL-1-induced activation of pro-MMP-2. In contrast to dexamethasone, TPCA-1 inhibited the phosphorylation and degradation of IB␣ and the nuclear translocation of NF-B induced by IL-1. CONCLUSIONS. An IKK-2 inhibitor blocked IL-1-induced collagen degradation by corneal fibroblasts by inhibiting the activation of the NF-B signaling pathway and the upregulation of MMPs. IKK-2 inhibitors are thus potential alternatives to dexamethasone for the treatment of corneal ulcer.
The Journal of Biological Chemistry, 1999
In response to cutaneous injury, expression of collagenase-1 is induced in keratinocytes via ␣ 2  1 contact with native type I collagen, and enzyme activity is essential for cell migration over this substratum. However, the cellular mechanism(s) mediating integrin signaling remain poorly understood. We demonstrate here that treatment of keratinocytes cultured on type I collagen with epidermal growth factor receptor (EGFR) blocking antibodies or a specific receptor antagonist inhibited cell migration across type I collagen and the matrix-directed stimulation of collagenase-1 production. Additionally, stimulation of collagenase-1 expression by hepatocyte growth factor, transforming growth factor-1, and interferon-␥ was blocked by EGFR inhibitors, suggesting a required EGFR autocrine signaling step for enzyme expression. Collagenase-1 mRNA was not detectable in keratinocytes isolated immediately from normal skin, but increased progressively following 2 h of contact with collagen. In contrast, EGFR mRNA was expressed at high steady-state levels in keratinocytes isolated immediately from intact skin but was absent following 2 h cell contact with collagen, suggesting down-regulation following receptor activation. Indeed, tyrosine phosphorylation of the EGFR was evident as early as 10 min following cell contact with collagen. Treatment of keratinocytes cultured on collagen with EGFR antagonist or heparin-binding (HB)-EGF neutralizing antibodies dramatically inhibited the sustained expression (6 -24 h) of collagenase-1 mRNA, whereas initial induction by collagen alone (2 h) was unaffected. Finally, expression of collagenase-1 in ex vivo wounded skin and re-epithelialization of partial thickness porcine burn wounds was blocked following treatment with EGFR inhibitors. These results demonstrate that keratinocyte contact with type I collagen is sufficient to induce collagenase-1 expression, whereas sustained enzyme production requires autocrine EGFR activation by HB-EGF as an obligatory intermediate step, thereby maintaining collagenase-1-dependent migration during the re-epithelialization of epidermal wounds.
Pathogenesis of fibrosis: type 1 collagen and the skin
Journal of Molecular Medicine, 1998
This review on the pathogenesis of fibrosis emphasizes the similarities between tissue repair, a tightly regulated salutary biological response, and fibrosis, an unregulated pathological process. It focuses on the transcriptional regulation of type I collagen, the role of cytokines in fibroblast activation, integrins as examples of cell-matrix signaling pathways, and the heterogeneity of fibroblast populations as factors contributing to fibrosis. Tissue remodeling and the role of matrix metalloproteinases and metalloproteinase inhibitors are mentioned briefly. The capacity of extracellular matrix to modulate cellular function is a recurring theme.
… ophthalmology & visual …, 1999
PURPOSE. Expression of the genes for collagenase and interleukin-la (IL-la) are induced as stromal cells become activated to the repair fibroblast phenotype after injury to the cornea. This investigation examines the mechanisms whereby expression of these genes is inhibited by transforming growth factor-j3 (TGF-/3), dexamethasone (DEX), or retinoic acid (RET A). METHODS. A model of freshly isolated cultures of corneal stromal cells and early passage cultures of corneal fibroblasts was used in these studies. This model reproduces the events of stromal cell activation in the corneal wound. RESULTS. In early passage cultures of corneal fibroblasts, expression of collagenase is under obligatory control by autocrine IL-la. IL-la controls its own expression through an autocrine feedback loop that is dependent on transcription factor NF-KB. TGF-0, DEX, and RET A were each effective inhibitors of collagenase gene expression in these cells. Furthermore, these agents have the capacity to inhibit expression of IL-la and this was correlated with their ability to affect DNA-binding activity of NF-KB. However, TGF-/3, DEX, and RET A were also effective inhibitors of the low level of collagenase expressed by freshly isolated corneal stromal cells that cannot express IL-la. CONCLUSIONS. In cells with an active IL-la autocrine loop there are at least two distinct signaling pathways by which collagenase gene expression can be modulated. The results of this study demonstrate that TGF-/3, DEX, and RET A differentially inhibit collagenase and IL-la gene expression. This information will be useful in the design of therapeutic modalities for fibrotic disease in the cornea and other parts of the eye.