The WNT signalling modulator, wise, is expressed in an interaction- dependent manner during hair-follicle cycling

Abstract

We used microarray hybridisation to identify genes induced in the dermal papilla (DP) during anagen as a result of the interaction with epithelial matrix cells. We identified inhibitors of the bone morphogenetic protein (BMP) and transforming growth factor β (TGFβ)-signalling pathway, as well as the rat homologue of the Xenopus-secreied WNT modulator Wise. A large number of genes previously determined to be expressed in the DP were shown to be expressed in both the DP and dermal sheath (DS). Genes induced in the DP during anagen included modulators of genes expressed additionally in the DS as well as specialised extracellular matrix components. Expression of some of these genes were lost when the DP cells were cultured, suggesting that their expression was interaction dependent. One such gene, the WMT-signalling modulator Wise, was expressed in the DP and not in the non-inductive DS and was additionally expressed at high levels in the precortex and in the putative bulge region. In addition to the reported WNT-signalling modulation role, we show that Wise reduced both BMP and TGFp signalling in transformed fibroblasts. We speculate that loss of gene expression in cultured cells is a model for the loss of gene expression observed at catagen.