毛包誘導活性を有する毛乳頭細胞のセクレトーム解析

抄録

Epithelial-mesenchymal interactions play a pivotal role in hair morphogenesis. We hypothesized that the dermal papilla (DP) cells may secrete soluble molecules that induce the differentiation of epidermal cells into hair follicle in vivo as well as in vitro. To comprehensively identify these molecules, we performed a secretomic study by comparing the secreted proteins of cultured rat DP cells with those of rat fibroblasts.
These two types of cells were serially subcultured in serum-containing growth media as previously reported and then cultured in a special serum-free media for additional 48 h. The 48h-culturing serum-free media were harvested as conditioned media (CM) that contained proteins secreted by each of the cell types and subjected to scretome analysis. The CM proteins were separated by 2D PAGE. Comparison of the protein distribution profiles between the two types of cells enabled us to successfully identify 25 proteins that were exclusively expressed in DP cells. Among them MMP13 was worthy of further characterization because its expression was exceedingly high in DP cells and tissue inhibitor of metalloproteinases 1 (TIMP1) was one of the preferentially expressed proteins in DP cells.The expression of MMP13 mRNA was also markedly upregulated in DP cells compared to fibroblasts.
To investigate the function of MMP13 in the DP cell-dependent hair induction, we transplanted DP cells and rat epidermal cells into the back of nude mice in a manner that the transplants contained varied amounts of TIMP1. The results of the graft reproducibly showed that the hairs induced by the graft cells were suppressed in a TIMP1 dose-dependent manner. These data indicated that MMP13 activity is necessary for sustaining the hair inducing ability of DP cells and consequently identified MMP13 as a protein that functions in the process of hair induction from epidermal cells by DP cells.