Myofibroblast differentiation is induced in keratinocyte-fibroblast co-cultures and is antagonistically regulated by endogenous transforming growth factor-β and …

P Shephard, G Martin, S Smola-Hess, G Brunner… - The American journal of …, 2004 - Elsevier
P Shephard, G Martin, S Smola-Hess, G Brunner, T Krieg, H Smola
The American journal of pathology, 2004Elsevier
In wound healing epidermal-dermal interactions are known to regulate keratinocyte
proliferation and differentiation. To find out how fibroblasts respond to epithelial stimuli, we
characterized fibroblasts in monolayer co-culture with keratinocytes. On co-culture
numerous extracellular matrix-and smooth muscle cell-associated gene transcripts were up-
regulated in fibroblasts, suggesting a differentiation into myofibroblasts. Increased α-smooth
muscle actin (α-SMA) protein expression in co-cultured fibroblasts started at approximately …
In wound healing epidermal-dermal interactions are known to regulate keratinocyte proliferation and differentiation. To find out how fibroblasts respond to epithelial stimuli, we characterized fibroblasts in monolayer co-culture with keratinocytes. On co-culture numerous extracellular matrix- and smooth muscle cell-associated gene transcripts were up-regulated in fibroblasts, suggesting a differentiation into myofibroblasts. Increased α-smooth muscle actin (α-SMA) protein expression in co-cultured fibroblasts started at approximately day 4, was serum-independent, but required endogenous transforming growth factor (TGF)-β. In co-cultures, TGF-β neutralizing monoclonal antibody strongly reduced α-SMA induction. Endogenous TGF-β production and activation were increased at 24 and 48 hours, requiring, like α-SMA induction, close keratinocyte-fibroblast proximity. As myofibroblast differentiation only started after 4 days, we analyzed the presence of endogenous inhibitors at early time points. Blocking keratinocyte-derived interleukin (IL)-1 using IL-1 receptor antagonist, α-SMA expression in co-cultures was potentiated. Conversely, adding exogenous IL-1α completely suppressed endogenous α-SMA induction. In co-cultured fibroblasts strong nuclear factor-κB binding activity was observed from 2 hours, decreasing at 2 and 4 days, suggesting an early, IL-1-mediated inhibition of TGF-β signaling in co-cultured fibroblasts. This biphasic differentiation event is regulated by the balance of endogenous TGF-β and IL-1 activity and is reminiscent of myofibroblast differentiation at early and later stages of wound healing.
Elsevier