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Keratinocyte stimulation of matrix metalloproteinase-1 production and proliferation in fibroblasts: regulation through mitogen-activated protein kinase signalling events.

Moon SE, Bhagavathula N, Varani J - Br. J. Cancer (2002)

Bottom Line: In fibroblasts exposed to keratinocyte-conditioned medium, mitogen-activated protein kinase signalling through both the extracellular signal-related kinase pathway and p38 pathway occurred.A p38 signalling inhibitor (SB203580) blocked matrix metalloproteinase-1 elaboration induced by keratinocyte-conditioned medium or interleukin-1beta, but did not inhibit matrix metalloproteinase-1 elaboration or cell growth induced by epidermal growth factor.These data indicate that keratinocyte-fibroblast interactions are mediated by multiple stimulating agents acting on specific receptors to induce signalling through different mitogen-activated protein kinase pathways leading to altered expression of key biological functions.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, The University of Michigan Medical School, 1301 Catherine Road, Box 0602, Ann Arbor, Michigan, MI 48109, USA.

ABSTRACT
Incubation of human dermal fibroblasts in keratinocyte-conditioned culture medium led to a 5.7-fold increase in the level of matrix metalloproteinase-1. Virtually all of the matrix metalloproteinase-1 - inducing activity could be related to agonists acting through members of the epidermal growth factor receptor family or to agonists acting through the interleukin-1 receptor. The same keratinocyte-conditioned medium also induced a modest increase in fibroblast proliferation (approximately 1.8-fold). Growth-stimulating activity could be attributed to epidermal growth factor receptor (but not interleukin-1 receptor) function. In fibroblasts exposed to keratinocyte-conditioned medium, mitogen-activated protein kinase signalling through both the extracellular signal-related kinase pathway and p38 pathway occurred. When recombinant epidermal growth factor or recombinant interleukin-1beta were used as a control, they induced mitogen-activated protein kinase signalling consistent with the combined effects of epidermal growth factor receptor - specific and interleukin-1 receptor - specific agonists in keratinocyte-conditioned medium. Recombinant epidermal growth factor stimulated both matrix metalloproteinase-1 induction and proliferation while recombinant interleukin-1beta stimulated matrix metalloproteinase-1 elaboration but not fibroblast growth. An inhibitor of extracellular signal-related kinase pathway signalling (U0126) blocked induction of matrix metalloproteinase-1 production induced by keratinocyte-conditioned medium (as well as by epidermal growth factor or interleukin-1beta), and also inhibited proliferation. A p38 signalling inhibitor (SB203580) blocked matrix metalloproteinase-1 elaboration induced by keratinocyte-conditioned medium or interleukin-1beta, but did not inhibit matrix metalloproteinase-1 elaboration or cell growth induced by epidermal growth factor. These data indicate that keratinocyte-fibroblast interactions are mediated by multiple stimulating agents acting on specific receptors to induce signalling through different mitogen-activated protein kinase pathways leading to altered expression of key biological functions.

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Effects of SB203580 on p38 phosphorylation induced by keratinocyte-conditioned medium or IL-1β. Fibroblasts were exposed for 30 or 60 min to culture medium alone or to a 50 : 50 mixture of culture medium and keratinocyte-conditioned medium with or without 15 μM SB203580. At the end of the incubation period, extracts were prepared and assayed for phospho-p38 expression as described in the Materials and Methods section. Values shown are expressed as fold-induction relative to the level detected in cells exposed to culture medium alone. The insert demonstrates a Western blot from one experiment. p38-P=phosphorylated p38. p38-SS=total p38 protein.
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fig6: Effects of SB203580 on p38 phosphorylation induced by keratinocyte-conditioned medium or IL-1β. Fibroblasts were exposed for 30 or 60 min to culture medium alone or to a 50 : 50 mixture of culture medium and keratinocyte-conditioned medium with or without 15 μM SB203580. At the end of the incubation period, extracts were prepared and assayed for phospho-p38 expression as described in the Materials and Methods section. Values shown are expressed as fold-induction relative to the level detected in cells exposed to culture medium alone. The insert demonstrates a Western blot from one experiment. p38-P=phosphorylated p38. p38-SS=total p38 protein.

Mentions: In the next set of experiments, effects of SB203580 on p38 phosphorylation induced by keratinocyte culture fluid was assessed. Consistent with the findings presented in Figure 4, p38 phosphorylation was increased at 30 min under control conditions (i.e., in the presence of keratinocyte-conditioned medium) and then decreased almost to baseline by 60 min. In the presence of both the keratinocyte culture fluid and the inhibitor, the level of phosphorylation seen at 30 min was increased slightly over that seen with culture fluid alone. More impressively, the decrease seen at 60 min in the presence of culture fluid was substantially inhibited in the presence of SB203580 (Figure 6Figure 6


Keratinocyte stimulation of matrix metalloproteinase-1 production and proliferation in fibroblasts: regulation through mitogen-activated protein kinase signalling events.

Moon SE, Bhagavathula N, Varani J - Br. J. Cancer (2002)

Effects of SB203580 on p38 phosphorylation induced by keratinocyte-conditioned medium or IL-1β. Fibroblasts were exposed for 30 or 60 min to culture medium alone or to a 50 : 50 mixture of culture medium and keratinocyte-conditioned medium with or without 15 μM SB203580. At the end of the incubation period, extracts were prepared and assayed for phospho-p38 expression as described in the Materials and Methods section. Values shown are expressed as fold-induction relative to the level detected in cells exposed to culture medium alone. The insert demonstrates a Western blot from one experiment. p38-P=phosphorylated p38. p38-SS=total p38 protein.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2376127&req=5

fig6: Effects of SB203580 on p38 phosphorylation induced by keratinocyte-conditioned medium or IL-1β. Fibroblasts were exposed for 30 or 60 min to culture medium alone or to a 50 : 50 mixture of culture medium and keratinocyte-conditioned medium with or without 15 μM SB203580. At the end of the incubation period, extracts were prepared and assayed for phospho-p38 expression as described in the Materials and Methods section. Values shown are expressed as fold-induction relative to the level detected in cells exposed to culture medium alone. The insert demonstrates a Western blot from one experiment. p38-P=phosphorylated p38. p38-SS=total p38 protein.
Mentions: In the next set of experiments, effects of SB203580 on p38 phosphorylation induced by keratinocyte culture fluid was assessed. Consistent with the findings presented in Figure 4, p38 phosphorylation was increased at 30 min under control conditions (i.e., in the presence of keratinocyte-conditioned medium) and then decreased almost to baseline by 60 min. In the presence of both the keratinocyte culture fluid and the inhibitor, the level of phosphorylation seen at 30 min was increased slightly over that seen with culture fluid alone. More impressively, the decrease seen at 60 min in the presence of culture fluid was substantially inhibited in the presence of SB203580 (Figure 6Figure 6

Bottom Line: In fibroblasts exposed to keratinocyte-conditioned medium, mitogen-activated protein kinase signalling through both the extracellular signal-related kinase pathway and p38 pathway occurred.A p38 signalling inhibitor (SB203580) blocked matrix metalloproteinase-1 elaboration induced by keratinocyte-conditioned medium or interleukin-1beta, but did not inhibit matrix metalloproteinase-1 elaboration or cell growth induced by epidermal growth factor.These data indicate that keratinocyte-fibroblast interactions are mediated by multiple stimulating agents acting on specific receptors to induce signalling through different mitogen-activated protein kinase pathways leading to altered expression of key biological functions.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, The University of Michigan Medical School, 1301 Catherine Road, Box 0602, Ann Arbor, Michigan, MI 48109, USA.

ABSTRACT
Incubation of human dermal fibroblasts in keratinocyte-conditioned culture medium led to a 5.7-fold increase in the level of matrix metalloproteinase-1. Virtually all of the matrix metalloproteinase-1 - inducing activity could be related to agonists acting through members of the epidermal growth factor receptor family or to agonists acting through the interleukin-1 receptor. The same keratinocyte-conditioned medium also induced a modest increase in fibroblast proliferation (approximately 1.8-fold). Growth-stimulating activity could be attributed to epidermal growth factor receptor (but not interleukin-1 receptor) function. In fibroblasts exposed to keratinocyte-conditioned medium, mitogen-activated protein kinase signalling through both the extracellular signal-related kinase pathway and p38 pathway occurred. When recombinant epidermal growth factor or recombinant interleukin-1beta were used as a control, they induced mitogen-activated protein kinase signalling consistent with the combined effects of epidermal growth factor receptor - specific and interleukin-1 receptor - specific agonists in keratinocyte-conditioned medium. Recombinant epidermal growth factor stimulated both matrix metalloproteinase-1 induction and proliferation while recombinant interleukin-1beta stimulated matrix metalloproteinase-1 elaboration but not fibroblast growth. An inhibitor of extracellular signal-related kinase pathway signalling (U0126) blocked induction of matrix metalloproteinase-1 production induced by keratinocyte-conditioned medium (as well as by epidermal growth factor or interleukin-1beta), and also inhibited proliferation. A p38 signalling inhibitor (SB203580) blocked matrix metalloproteinase-1 elaboration induced by keratinocyte-conditioned medium or interleukin-1beta, but did not inhibit matrix metalloproteinase-1 elaboration or cell growth induced by epidermal growth factor. These data indicate that keratinocyte-fibroblast interactions are mediated by multiple stimulating agents acting on specific receptors to induce signalling through different mitogen-activated protein kinase pathways leading to altered expression of key biological functions.

Show MeSH
Related in: MedlinePlus