Dermatol Ther. 2015 Mar;28(2):65-67. doi: 10.1111/dth.12197. Epub 2015 Jan 28.

Erosive pustular dermatosis of the scalp following topical latanoprost for androgenetic alopecia.

Vaccaro M¹, Barbuzza O, Borgia F, Cannavò SP.

Thyroid hormone signaling controls hair follicle stem cell function.

Contreras-Jurado C1, Lorz C2, García-Serrano L1, Paramio JM3, Aranda A4.

Author information

Abstract

Observations in thyroid patients and experimental animals show that the skin is an important target for the thyroid hormones. We previously showed that deletion in mice of the thyroid hormone nuclear receptors TRα1 and TRβ (the main thyroid hormone-binding isoforms) results in impaired epidermal proliferation, hair growth, and wound healing. Stem cells located at the bulges of the hair follicles are responsible for hair cycling and contribute to the regeneration of the new epidermis after wounding. Therefore a reduction in the number or function of the bulge stem cells could be responsible for this phenotype. Bulge cells show increased levels of epigenetic repressive marks, can retain bromodeoxyuridine labeling for a long time, and have colony-forming efficiency (CFE) in vitro. Here we demonstrate that mice lacking TRs do not have a decrease of the bulge stem cell population. Instead, they show an increase of label-retaining cells (LRCs) in the bulges and enhanced CFE in vitro. Reduced activation of stem cells leading to their accumulation in the bulges is indicated by a strongly reduced response to mobilization by 12-O-tetradecanolyphorbol-13-acetate. Altered function of the bulge stem cells is associated with aberrant activation of Smad signaling, leading to reduced nuclear accumulation of β-catenin, which is crucial for stem cell proliferation and mobilization. LRCs of TR-deficient mice also show increased levels of epigenetic repressive marks. We conclude that thyroid hormone signaling is an important determinant of the mobilization of stem cells out of their niche in the hair bulge. These findings correlate with skin defects observed in mice and alterations found in human thyroid disorders.

© 2015 Contreras-Jurado et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

[Regulation of hair follicle cycle].

[Article in Russian]

[No authors listed]

Abstract

This review is devoted to the control of hair growth. The hair follicle undergoes cyclic transformation from the resting phase (telogen) to the growth phase (anagen). The latter phase is characterized by rapid proliferation of follicular keratinocytes and elongation and thickening of the hair shaft. The regression phase (catagen) leads to the involution of the hair follicle. These cyclic changes include rapid remodeling of both the epithelial and the dermal components. They are controlled by numerous different factors: sex hormones, neurotrophins, FGF, TGF, BMP, VEGF, Sonic Hedgehog, and other signaling pathways.

Follistatin and secreted frizzled-related protein 1, OVO homolog-like 1-regulated genes, are important for hairfollicle neogenesis.

Bak SS1, Kim MK, Kim JC, Sung YK.

Author information

Abstract

Recent studies showed that Wnt signaling through the β-catenin pathway maintains the hair inducing capacity (trichogenicity) of the dermal papilla cells and that inactivation of the β-catenin gene within the dermal papilla of fully developed hair follicles prevented the normal regeneration of hairfollicles (1,2). This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.

Hair Regeneration Treatment Using Adipose-Derived Stem Cell Conditioned Medium: Follow-up With Trichograms

http://www.eplasty.com/images/PDF/eplasty15e10.pdf

2015 Apr;13(4):302-6. doi: 10.1111/ddg.12620.

Wnt signaling in skin homeostasis and pathology.

Augustin I1.

Author information

Abstract

The mammalian skin mediates the primary interphase between the body and the external environment and provides the first line of defense against pathogens, mechanical trauma, sunlight injuries, and chemical stress. Proper physical, biochemical, and immunological composition of the skin is necessary to maintain its barrier function. Therefore, the skin reflects a complex dynamic organ with high cellular turnover during normal tissue replacement and wound repair. Stem cell reservoirs ensure constant skin renewal. Wnt signaling controls stem cell maintenance and fate decisions in various tissues and also reflects a key pathway in controlling skin development and homeostasis. Disruption of Wnt signaling in the skin causes disorders such as alopecia, chronic inflammatory skin diseases or cancer. This review summarizes the role of Wnt signaling during skin development, homeostasis, and disease.

© 2015 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

Exp Dermatol. 2012 Dec;21(12):956-8. doi: 10.1111/exd.12033.

Extracellular histones inhibit hair shaft elongation in cultured human hair follicles and promote regression of hair follicles in mice.

Shin SH, Joo HW, Kim MK, Kim JC, Sung YK.

Abstract

Release of histone H4 in rat vibrissa dermal papilla (DP) cells exposed to sub-toxic dose of colchicines has been recently reported. In addition, exposure to histone H4 has been reported to result in inhibited proliferation and reduced alkaline phosphatase (ALP) activity of cultured vibrissa DP cells. These findings prompted us to investigate the role of extracellular histones in hair growth using cultured human hair follicles and hair cycling using back skin of mice. We report here that exposure of cultured hair follicles to histone H4 and H2A resulted in significant inhibition of elongation of hair shafts, decreased expression of IGF-1 and decreased expression and activity of ALP. Injection of histones into hypodermis of mice during anagen resulted in premature onset of catagen. Findings of the current study provide strong evidence suggesting the inhibitory role of extracellular histones in hair growth.

© 2012 John Wiley & Sons A/S.