Transient activation of beta -catenin signaling in cutaneous keratinocytes is sufficient to trigger the active growth phase of the hair cycle in mice - PubMed (original) (raw)

Transient activation of beta -catenin signaling in cutaneous keratinocytes is sufficient to trigger the active growth phase of the hair cycle in mice

David Van Mater et al. Genes Dev. 2003.

Abstract

Wnts have key roles in many developmental processes, including hair follicle growth and differentiation. Stabilization of beta-catenin is essential in the canonical Wnt signaling pathway. We developed transgenic mice expressing a regulated form of beta-catenin in the skin. Chronic activation of beta-catenin in resting (telogen) hair follicles resulted in changes consistent with induction of an exaggerated, aberrant growth phase (anagen). Transient activation of beta-catenin produced a normal anagen. Our data lend strong support to the notion that a Wnt/beta-catenin signal operating on hair follicle precursor cells serves as a crucial proximal signal for the telogen-anagen transition.

PubMed Disclaimer

Figures

Figure 1

Figure 1

Activation of the K5/S33Yβ-catenin–ER protein by 4-OHT and expression in transgenic mice. (A) Schematic of the K5/S33Yβ-catenin–ER construct. A cDNA encoding the chimeric protein was subcloned into a bovine K5 expression cassette. (B) Activity of the K5/S33Yβ-catenin–ER protein is inducible by 4-OHT in 1811 keratinocytes. The 1811 keratinocytes were transfected with an empty K5 cassette, the pBabe/S33Yβ-catenin–ER construct, or the K5/S33Yβ-catenin–ER construct along with either the TCF-responsive reporter construct TOPFLASH or control FOPFLASH construct. Cells were then treated with either 4-OHT in ethanol, or ethanol alone, and harvested 30 h later to assess luciferase activity. The assays were performed in duplicate; data are reported as the ratio of relative light units for TOPFLASH:FOPFLASH, normalized for transfection efficiency. (C) Expression of the K5/S33Yβ-catenin–ER fusion protein relative to endogenous β-catenin in transgenic mouse lines. Protein was isolated from tail skin of F1 mice derived from three independently derived founders and subjected to Western blot analysis with a mouse monoclonal anti-β-catenin antibody. The blot was reprobed with an anti-β-actin antibody to verify equal loading and transfer. (D) β-catenin protein localization in a clipped region of dorsal skin from K5/S33Yβ-catenin–ER transgenic mice not treated (−4-OHT) or 24 h after treatment with a single topical dose of 4-OHT (+4-OHT).

Figure 2

Figure 2

Growth and differentiation of the hair follicle in K5/S33Yβ-catenin–ER mice treated daily with 4-OHT. A region of dorsal hair was clipped on both transgenic and wild-type littermates and the skin area was treated daily with 4-OHT in ethanol. Parasagittal sections of skin were taken at time points following initiation of treatment and stained with hematoxylin and eosin. Hair follicles in wild-type mice remained in the resting phase (telogen) throughout the experiment; growth and differentiation of transgenic hair follicles was dramatically stimulated.

Figure 3

Figure 3

Altered expression of hair follicle markers in K5/S33Yβ-catenin–ER mice. Immunohistochemistry and immunofluorescence were performed on parasagittal sections of skin from both wild-type and K5/S33Yβ-catenin–ER mice in addition to a normal, spontaneous anagen cycle in a C57BL/6J mouse. The markers used were as follows: BrdU (a–c), K17 (d–f), K6 (g–i), K5 (j–l), trichohyalin (m–o), hair keratin (p–r), and alkaline phosphatase staining for dermal papillae (s–u). White arrows highlight ectopic trichohyalin staining in n. Bars: a–l,s–u, 100 μm; m–r, 200 μm.

Figure 4

Figure 4

Transient treatment with 4-OHT is sufficient for normal anagen induction in K5/S33Yβ-catenin–ER mice. (A) Hair growth in K5/S33Yβ-catenin–ER mice following a single topical treatment with 4-OHT. The experiment was performed on L2 transgenic mice obtained following backcrossing to C57BL/6J mice for six generations. Hair on wild-type and transgenic littermates was clipped and the skin region treated with a single dose of 4-OHT in ethanol or ethanol alone. Hair growth at 17 d after 4-OHT treatment is shown. (B) Histology of hair follicles in K5/S33Yβ-catenin–ER mice over time after a single treatment with 4-OHT. A cohort of transgenic mice was clipped and treated with 4-OHT and followed for a period of 28 d. Parasagittal skin sections obtained at various times after 4-OHT treatment were stained with hematoxylin and eosin. Bar, 100 μm.

Similar articles

Cited by

References

    1. Andl T, Reddy ST, Gaddapara T, Millar SE. WNT signals are required for the initiation of hair follicle development. Dev Cell. 2002;2:643–653. - PubMed
    1. Chanda S, Robinette CL, Couse JF, Smart RC. 17β-estradiol and ICI-182780 regulate the hair follicle cycle in mice through an estrogen receptor-α pathway. Am J Physiol Endocrinol Metab. 2000;278:E202–E210. - PubMed
    1. DasGupta R, Fuchs E. Multiple roles for activated LEF/TCF transcription complexes during hair follicle development and differentiation. Development. 1999;126:4557–4568. - PubMed
    1. Fuchs E, Merrill BJ, Jamora C, DasGupta R. At the roots of a never-ending cycle. Dev Cell. 2001;1:13–25. - PubMed
    1. Gat U, DasGupta R, Degenstein L, Fuchs E. De Novo hair follicle morphogenesis and hair tumors in mice expressing a truncated beta-catenin in skin. Cell. 1998;95:605–614. - PubMed

Publication types

MeSH terms

Substances

Grants and funding

LinkOut - more resources