Pitx2, a β-catenin-regulated transcription factor, regulates the differentiation of outer root sheath cells cultured in vitro

Backgroundβ-Catenin exerts its crucial role in hair follicle development and hair growth cycle. Although the importance of Wnt/β-catenin is well recognized, the downstream effectors of β-catenin have not been clearly elucidated yet.ObjectiveThe aim of this study is to identify the β-catenin-regulated genes in cultured human hair outer root sheath (ORS) cells.MethodsWe transduced ORS cells with adenovirus harboring the expression cassette for constitutive active form of β-catenin, then performed cDNA microarray.ResultsOverexpression of β-catenin led to the upregulation of hair cell differentiation markers such as keratin 16 and 17. In addition, the expression of Pitx2, a bicoid-type homeodomain transcription factor, was also increased by overexpression of β-catenin in ORS cells cultured in vitro. To investigate the potential role of Pitx2, we made the recombinant adenovirus expressing Pitx2, then transduced into the cultured ORS cells. Interestingly, Pitx2 induced the expression of keratin 16 and 17, indicating that Pitx2 activates ORS cells towards the follicular differentiation pathway preferentially.ConclusionOur results implicate the potential importance of Pitx2 as a β-catenin downstream modulator in hair growth control.