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Thyroid hormone signaling controls hair follicle stem cell function
Constanza Contreras-Jurado1, Corina Lorz2, Laura García-Serrano1
1Instituto de Investigaciones Biomédicas "Alberto Sols," Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, 28029 Madrid, Spain.
Molecular Biology of the Cell
|February 7, 2015
Summary
Thyroid hormone signaling is crucial for skin health. Lacking thyroid hormone receptors (TRs) in mice increases bulge stem cells, impairing their mobilization and leading to skin defects.
Area of Science:
- Endocrinology
- Dermatology
- Stem Cell Biology
Background:
- Thyroid hormones are vital for skin homeostasis, affecting epidermal proliferation, hair growth, and wound healing.
- Thyroid hormone nuclear receptors (TRα1 and TRβ) are the main mediators of thyroid hormone action.
- Hair follicle bulge stem cells are critical for hair cycling and epidermal regeneration.
Purpose of the Study:
- To investigate the role of thyroid hormone signaling in hair follicle bulge stem cell function.
- To determine if TR deficiency affects bulge stem cell number, function, or mobilization.
- To elucidate the molecular mechanisms underlying TR-mediated effects on stem cells.
Main Methods:
- Analysis of bulge stem cell populations in mice lacking TRα1 and TRβ.
- Assessment of label-retaining cells (LRCs) and colony-forming efficiency (CFE) in vitro.
- Evaluation of stem cell mobilization using 12-O-tetradecanolyphorbol-13-acetate and analysis of Smad and β-catenin signaling pathways.
Main Results:
- Mice lacking TRs showed no decrease in bulge stem cell numbers but an increase in LRCs and enhanced CFE.
- TR-deficient stem cells exhibited reduced mobilization and aberrant Smad signaling, with decreased nuclear β-catenin.
- LRCs in TR-deficient mice displayed increased epigenetic repressive marks.
Conclusions:
- Thyroid hormone signaling regulates the mobilization of stem cells from the hair follicle bulge niche.
- TR deficiency leads to stem cell accumulation in the bulge due to impaired mobilization.
- These findings link thyroid hormone action to skin defects and human thyroid disorders.
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