Figure 5.

Fgf9 secreted from γδ T cells induces a feedback loop resulting in widespread wound dermal Wnt activation. (a) qPCR analyses of Wnt2 (black) and Wnt10a (gray) expression in C57BL/6 (WT) or Tcrd^−/− wound fibroblasts cultured with the indicated concentrations of recombinant Fgf9 protein. Samples were normalized to equivalent 18S rRNA levels and transcript levels of Wnt2 and Wnt10a compared to that normalized value³⁰. Results are representative of three independent experiments. (b) qPCR analyses of Wnt2 and Fgf9 expression in sorted WT and Tcrd^−/− fibroblasts taken directly from PWD10, PWD12 and PWD14 wounds. Wound dermis from ten mice was combined and cells sorted for each experiment. Results are representative of three independent experiments. (c) qPCR analyses of Fgf9 expression in C57BL/6 γδ T cells and fibroblasts sorted from PWD10, PWD11, PWD12 and PWD14 wounds. For each time point, wound dermis from 10–15 mice was combined and sorted. Results represent three independent experiments. *P < 0.05. (d) ELISA analyses of secreted Fgf9 protein from wound fibroblasts of Axin2-LacZ mice, cultured with the indicated concentrations of recombinant Wnt2a protein for 24 h, 48 h and 72 h. Results are representative of three independent experiments. (e) Model depicting Fgf9-driven Wnt activation feedback loop. Boxed region in the bottom image (inset) shows the dermal location of fibroblasts undergoing Fgf9 activation and Wnt2a expression (top left), Wnt activation (top middle) and new Fgf9 expression (top right). Data are expressed as means ± s.e.m.