Abstract
The role of innate immunocytes such as mast cells, γδ T cells, NK cells and macrophages (MACs) in hair growth control under physiological and pathological conditions has recently begun to be re-explored. Here, we revisit the role of resident perifollicular macrophages (pfMACs) located in the hair follicle (HF) mesenchyme (CTS). Substantial, stringently timed fluctuations in the number and localization of pfMACs were first observed long ago during murine HF morphogenesis and cycling. This already suggested some involvement of these innate immunocytes, with a recognized role in tissue remodelling and in hair growth control. The relatively recent demonstration of a Wnt signalling-driven crosstalk between these immunocytes and HF epithelial stem cells in telogen HFs, which promotes anagen induction, has reinvigorated interest in the role that pfMAC plays in hair biology. Besides the apoptosis-associated secretion of stem cell–activating Wnts and the differential secretion of HF-targeting growth factors such as FGF-5 and FGF5s from pfMACs, we also explore how MAC polarization, and thus function, may be influenced by the local metabolic and immune environment. Moreover, we examine how pfMACs may contribute to hair cycle–associated angiogenesis, vascular remodelling, HF immune privilege and immunopathology. On this basis, we discuss why targeting pfMACs may be relevant in the management of hair growth disorders. Finally, we argue that studying pfMACs offers an excellent, clinically relevant model system for characterizing and experimentally manipulating MAC interactions with an easily accessible mammalian, continuously remodelled (mini-)organ under both physiological and pathological conditions.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 425-431 |
| Number of pages | 7 |
| Journal | Experimental dermatology |
| Volume | 28 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 1 2019 |
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Keywords
- hair cycle
- hair follicle
- immunology
- macrophages
- skin
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Dermatology
Cite this
Hair growth control by innate immunocytes : Perifollicular macrophages revisited. / Muneeb, Ferhan; Hardman, Jonathan A.; Paus, Ralf.
In: Experimental dermatology, Vol. 28, No. 4, 01.04.2019, p. 425-431.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Hair growth control by innate immunocytes
T2 - Perifollicular macrophages revisited
AU - Muneeb, Ferhan
AU - Hardman, Jonathan A.
AU - Paus, Ralf
PY - 2019/4/1
Y1 - 2019/4/1
N2 - The role of innate immunocytes such as mast cells, γδ T cells, NK cells and macrophages (MACs) in hair growth control under physiological and pathological conditions has recently begun to be re-explored. Here, we revisit the role of resident perifollicular macrophages (pfMACs) located in the hair follicle (HF) mesenchyme (CTS). Substantial, stringently timed fluctuations in the number and localization of pfMACs were first observed long ago during murine HF morphogenesis and cycling. This already suggested some involvement of these innate immunocytes, with a recognized role in tissue remodelling and in hair growth control. The relatively recent demonstration of a Wnt signalling-driven crosstalk between these immunocytes and HF epithelial stem cells in telogen HFs, which promotes anagen induction, has reinvigorated interest in the role that pfMAC plays in hair biology. Besides the apoptosis-associated secretion of stem cell–activating Wnts and the differential secretion of HF-targeting growth factors such as FGF-5 and FGF5s from pfMACs, we also explore how MAC polarization, and thus function, may be influenced by the local metabolic and immune environment. Moreover, we examine how pfMACs may contribute to hair cycle–associated angiogenesis, vascular remodelling, HF immune privilege and immunopathology. On this basis, we discuss why targeting pfMACs may be relevant in the management of hair growth disorders. Finally, we argue that studying pfMACs offers an excellent, clinically relevant model system for characterizing and experimentally manipulating MAC interactions with an easily accessible mammalian, continuously remodelled (mini-)organ under both physiological and pathological conditions.
AB - The role of innate immunocytes such as mast cells, γδ T cells, NK cells and macrophages (MACs) in hair growth control under physiological and pathological conditions has recently begun to be re-explored. Here, we revisit the role of resident perifollicular macrophages (pfMACs) located in the hair follicle (HF) mesenchyme (CTS). Substantial, stringently timed fluctuations in the number and localization of pfMACs were first observed long ago during murine HF morphogenesis and cycling. This already suggested some involvement of these innate immunocytes, with a recognized role in tissue remodelling and in hair growth control. The relatively recent demonstration of a Wnt signalling-driven crosstalk between these immunocytes and HF epithelial stem cells in telogen HFs, which promotes anagen induction, has reinvigorated interest in the role that pfMAC plays in hair biology. Besides the apoptosis-associated secretion of stem cell–activating Wnts and the differential secretion of HF-targeting growth factors such as FGF-5 and FGF5s from pfMACs, we also explore how MAC polarization, and thus function, may be influenced by the local metabolic and immune environment. Moreover, we examine how pfMACs may contribute to hair cycle–associated angiogenesis, vascular remodelling, HF immune privilege and immunopathology. On this basis, we discuss why targeting pfMACs may be relevant in the management of hair growth disorders. Finally, we argue that studying pfMACs offers an excellent, clinically relevant model system for characterizing and experimentally manipulating MAC interactions with an easily accessible mammalian, continuously remodelled (mini-)organ under both physiological and pathological conditions.
KW - hair cycle
KW - hair follicle
KW - immunology
KW - macrophages
KW - skin
UR - http://www.scopus.com/inward/record.url?scp=85064902038&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85064902038&partnerID=8YFLogxK
U2 - 10.1111/exd.13922
DO - 10.1111/exd.13922
M3 - Article
C2 - 30920018
AN - SCOPUS:85064902038
VL - 28
SP - 425
EP - 431
JO - Experimental Dermatology
JF - Experimental Dermatology
SN - 0906-6705
IS - 4
ER -