101
|
Abstract
Nearly 50 years ago, Chase published a review of hair cycling in which he detailed hair growth in the mouse and integrated hair biology with the biology of his day. In this review we have used Chase as our model and tried to put the adult hair follicle growth cycle in perspective. We have tried to sketch the adult hair follicle cycle, as we know it today and what needs to be known. Above all, we hope that this work will serve as an introduction to basic biologists who are looking for a defined biological system that illustrates many of the challenges of modern biology: cell differentiation, epithelial-mesenchymal interactions, stem cell biology, pattern formation, apoptosis, cell and organ growth cycles, and pigmentation. The most important theme in studying the cycling hair follicle is that the follicle is a regenerating system. By traversing the phases of the cycle (growth, regression, resting, shedding, then growth again), the follicle demonstrates the unusual ability to completely regenerate itself. The basis for this regeneration rests in the unique follicular epithelial and mesenchymal components and their interactions. Recently, some of the molecular signals making up these interactions have been defined. They involve gene families also found in other regenerating systems such as fibroblast growth factor, transforming growth factor-beta, Wnt pathway, Sonic hedgehog, neurotrophins, and homeobox. For the immediate future, our challenge is to define the molecular basis for hair follicle growth control, to regenerate a mature hair follicle in vitro from defined populations, and to offer real solutions to our patients' problems.
Collapse
Affiliation(s)
- K S Stenn
- Beauty Genome Sciences Inc., Skillman, New Jersey, USA.
| | | |
Collapse
|
102
|
Botchkarev VA, Botchkareva NV, Albers KM, Chen LH, Welker P, Paus R. A role for p75 neurotrophin receptor in the control of apoptosis-driven hair follicle regression. FASEB J 2000; 14:1931-42. [PMID: 11023977 DOI: 10.1096/fj.99-0930com] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To examine the mechanisms that underlie the neurotrophin-induced, apoptosis-driven hair follicle involution (catagen), the expression and function of p75 neurotrophin receptor (p75NTR), which is implicated in apoptosis control, were studied during spontaneous catagen development in murine skin. By RT-PCR, high steady-state p75NTR mRNA skin levels were found during the anagen-catagen transition of the hair follicle. By immunohistochemistry, p75NTR alone was strongly expressed in TUNEL+/Bcl2- keratinocytes of the regressing outer root sheath, but both p75NTR and TrkB and/or TrkC were expressed by the nonregressing TUNEL-/Bcl2+ secondary hair germ keratinocytes. To determine whether p75NTR is functionally involved in catagen control, spontaneous catagen development was compared in vivo between p75NTR knockout (-/-) and wild-type mice. There was significant catagen retardation in p75NTR knockout mice as compared to wild-type controls (P<0.05). Instead, transgenic mice-overexpressing NGF (promoter: K14) showed substantial acceleration of catagen (P<0.001). Although NGF, brain-derived neurotrophic factor (BDNF), and neurotrophin 3 (NT-3) accelerated catagen in the organ-cultured skin of C57BL/6 mice, these neurotrophins failed to promote catagen development in the organ-cultured p75NTR null skin. These findings suggest that p75NTR signaling is involved in the control of kerotinocyte apoptosis during catagen and that pharmacological manipulation of p75NTR signaling may prove useful for the treatment of hair disorders that display premature entry into catagen.
Collapse
Affiliation(s)
- V A Botchkarev
- *Department of Dermatology, Charité, Humboldt University, Berlin, Germany
| | | | | | | | | | | |
Collapse
|
103
|
Foitzik K, Lindner G, Mueller-Roever S, Maurer M, Botchkareva N, Botchkarev V, Handjiski B, Metz M, Hibino T, Soma T, Dotto GP, Paus R. Control of murine hair follicle regression (catagen) by TGF-beta1 in vivo. FASEB J 2000; 14:752-60. [PMID: 10744631 DOI: 10.1096/fasebj.14.5.752] [Citation(s) in RCA: 250] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The regression phase of the hair cycle (catagen) is an apoptosis-driven process accompanied by terminal differentiation, proteolysis, and matrix remodeling. As an inhibitor of keratinocyte proliferation and inductor of keratinocyte apoptosis, transforming growth factor beta1 (TGF-beta1) has been proposed to play an important role in catagen regulation. This is suggested, for example, by maximal expression of TGF-beta1 and its receptors during late anagen and the onset of catagen of the hair cycle. We examined the potential involvement of TGF-beta1 in catagen control. We compared the first spontaneous entry of hair follicles into catagen between TGF-beta1 null mice and age-matched wild-type littermates, and assessed the effects of TGF-beta1 injection on murine anagen hair follicles in vivo. At day 18 p.p., hair follicles in TGF-beta1 -/- mice were still in early catagen, whereas hair follicles of +/+ littermates had already entered the subsequent resting phase (telogen). TGF-beta1-/- mice displayed more Ki-67-positive cells and fewer apoptotic cells than comparable catagen follicles from +/+ mice. In contrast, injection of TGF-beta1 into the back skin of mice induced premature catagen development. In addition, the number of proliferating follicle keratinocytes was reduced and the number of TUNEL + cells was increased in the TGF-beta1-treated mice compared to controls. Double visualization of TGF-beta type II receptor (TGFRII) and TUNEL reactivity revealed colocalization of apoptotic nuclei and TGFRII in catagen follicles. These data strongly support that TGF-beta1 ranks among the elusive endogenous regulators of catagen induction in vivo, possibly via the inhibition of keratinocyte proliferation and induction of apoptosis. Thus, TGF-betaRII agonists and antagonists may provide useful therapeutic tools for human hair growth disorders based on premature or retarded catagen development (effluvium, alopecia, hirsutism).
Collapse
Affiliation(s)
- K Foitzik
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA. Department of Dermatology, University Hospital Eppendorf, University of Hamburg, D-20246 Hamburg, Germany. Departme
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
104
|
Botchkareva NV, Botchkarev VA, Welker P, Airaksinen M, Roth W, Suvanto P, Müller-Röver S, Hadshiew IM, Peters C, Paus R. New roles for glial cell line-derived neurotrophic factor and neurturin: involvement in hair cycle control. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 156:1041-53. [PMID: 10702420 PMCID: PMC1876831 DOI: 10.1016/s0002-9440(10)64972-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF), neurturin (NTN), and their receptors, GDNF family receptor alpha-1 (GFRalpha-1) and GDNF family receptor alpha-2 (GFRalpha-2), are critically important for kidney and nervous system development. However, their role in skin biology, specifically in hair growth control, is as yet unknown. We have studied expression and function of GDNF, neurturin, GFRalpha-1, and GFRalpha-2 in murine skin during the cyclic transformation of the hair follicle (HF) from its resting state (telogen) to active growth (anagen) and then through regression (catagen) back to telogen. GDNF protein and GFRalpha-1 messenger RNA are prominently expressed in telogen skin, which lacks NTN and GFRalpha-2 transcripts. Early anagen development is accompanied by a significant decline in the skin content of GDNF protein and GFRalpha-1 transcripts. During the anagen-catagen transition, GDNF, GFRalpha-1, NTN, and GFRalpha-2 transcripts reach maximal levels. Compared with wild-type controls, GFRalpha-1 (+/-) and GFRalpha-2 (-/-) knockout mice show a significantly accelerated catagen development. Furthermore, GDNF or NTN administration significantly retards HF regression in organ-cultured mouse skin. This suggests important, previously unrecognized roles for GDNF/GFRalpha-1 and NTN/GFRalpha-2 signaling in skin biology, specifically in the control of apoptosis-driven HF involution, and raises the possibility that GFRalpha-1/GFRalpha-2 agonists/antagonists might become exploitable for the treatment of hair growth disorders that are related to abnormalities in catagen development.
Collapse
Affiliation(s)
- N V Botchkareva
- Department of Dermatology, Charité, Humboldt University, Berlin, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
105
|
Foitzik K, Paus R, Doetschman T, Dotto GP. The TGF-beta2 isoform is both a required and sufficient inducer of murine hair follicle morphogenesis. Dev Biol 1999; 212:278-89. [PMID: 10433821 DOI: 10.1006/dbio.1999.9325] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hair follicle development serves as an excellent model to study control of organ morphogenesis. Three specific isoforms of TGF-beta exist which exhibit a distinct pattern of expression during hair follicle morphogenesis. To clarify the still elusive role of these factors in hair follicle development, we have used a combined genetic and functional approach: analysis of hair follicle development in mice with disruptions of the TGF-beta1, 2, and 3 genes was coupled with a direct functional test of the effect of added purified factors on fetal hair follicle development in skin organ cultures. TGF-beta2 null mice exhibited a profound delay of hair follicle morphogenesis, with a 50% reduced number of hair follicles. In contrast to hair follicle development, growth and differentiation of interfollicular keratinocytes proceeded unimpaired. Unlike TGF-beta2-/- mice, mice with a disruption of the TGF-beta1 gene showed slightly advanced hair follicle formation, while lack of the TGF-beta3 gene did not have any effects. Treatment of wild-type, embryonic skin explants (E14.5 or E15.5) with TGF-beta2 protein in either soluble form or slow release beads induced hair follicle development and epidermal hyperplasia, while similar TGF-beta1 treatment exerted suppressive effects. Thus, the TGF-beta2 isoform plays a specific role, not shared by the other TGF-beta isoforms, as an inducer of hair follicle morphogenesis and is both required and sufficient to promote this process.
Collapse
Affiliation(s)
- K Foitzik
- Cutaneous Biology Research Center, Massachussetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, 02129, USA
| | | | | | | |
Collapse
|
106
|
Takeda A, Matsuhashi S, Shioya N, Ihara S. Histodifferentiation of hair follicles in grafting of cell aggregates obtained by rotation culture of embryonic rat skin. SCANDINAVIAN JOURNAL OF PLASTIC AND RECONSTRUCTIVE SURGERY AND HAND SURGERY 1998; 32:359-64. [PMID: 9862102 DOI: 10.1080/02844319850158435] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We have previously reported reconstruction of hair follicles from a single cell suspension of rat fetal upper lip by a two-step culture method consisting of rotation and flotation cultures. Rotation sorted out the cells and flotation facilitated histodifferentiation. In the present study, we added grafting procedures to the previous method to see whether cell aggregates obtained this way were graftable, and whether the grafting promoted histodifferentiation. The aggregates before and after flotation were grafted, and differentiation of hair follicles comparable to those in vivo was confirmed 10 days after grafting. There was no difference in the degree of differentiation between the two kinds of grafts. The grafting procedure therefore resulted in an appreciable increase in histodifferentiation even when aggregates obtained after flotation were grafted.
Collapse
Affiliation(s)
- A Takeda
- Department of Plastic and Reconstructive Surgery, Kitasato University School of Medicine, Kanagawa, Japan
| | | | | | | |
Collapse
|
107
|
Cook PW, Piepkorn M, Clegg CH, Plowman GD, DeMay JM, Brown JR, Pittelkow MR. Transgenic expression of the human amphiregulin gene induces a psoriasis-like phenotype. J Clin Invest 1997; 100:2286-94. [PMID: 9410906 PMCID: PMC508424 DOI: 10.1172/jci119766] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Amphiregulin (AR) is a heparin-binding, heparin-inhibited member of the epidermal growth factor (EGF) family and an autocrine growth factor for human keratinocytes. Previous studies have shown that AR expression is increased in psoriatic epidermis. To test the hypothesis that aberrant AR expression is central to the development of psoriatic lesions, we constructed a transgene (K14-ARGE) encoding a human keratin 14 promoter-driven AR gene. Our results indicate that transgene integration and subsequent expression of AR in basal keratinocytes correlated with a psoriasis-like skin phenotype. Afflicted mice demonstrated shortened life spans, prominent scaling and erythematous skin with alopecia, and occasional papillomatous epidermal growths. Histologic examination revealed extensive areas of marked hyperkeratosis with focal parakeratosis, acanthosis, dermal and epidermal lymphocytic and neutrophilic infiltration, and dilated blood vessels within the papillary dermis. Our results reveal that AR exerts activity in the skin that is distinct from that of transgenic transforming growth factor-alpha or other cytokines, and induces skin pathology with striking similarities to psoriasis. Our observations also link the keratinocyte EGF receptor-ligand system to psoriatic inflammation, and suggest that aberrant expression of AR in the epidermis may represent a critical step in the development or propagation of psoriatic lesions.
Collapse
Affiliation(s)
- P W Cook
- Department of Dermatology, The Oregon Health Sciences University, Portland 97201, USA.
| | | | | | | | | | | | | |
Collapse
|
108
|
Danilenko DM, Ring BD, Pierce GF. Growth factors and cytokines in hair follicle development and cycling: recent insights from animal models and the potentials for clinical therapy. MOLECULAR MEDICINE TODAY 1996; 2:460-7. [PMID: 8947911 DOI: 10.1016/1357-4310(96)10045-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Hair growth disorders, particularly those that lead to hair loss (alopecia), are common and frequently cause significant mental anguish in affected individuals. The mechanisms underlying the majority of these disorders are unknown. However, insights into the specific molecular mechanisms of hair follicle development and cycling have recently been made using animal models, particularly mice that over- or underexpress a specific gene for a growth factor or cytokine. Other animal models have demonstrated that certain growth factors and cytokines can prevent much of the alopecia caused by cancer chemotherapeutic agents. These animal models have confirmed the importance of growth factors and cytokines in hair follicle development and cycling, and have formed the foundation for potential clinical therapy of hair growth disorders, particularly alopecia. Nevertheless, important questions concerning their efficacy, safety and delivery will need to be answered before successful clinical therapy of any hair growth disorder becomes a reality.
Collapse
Affiliation(s)
- D M Danilenko
- Department of Pathology, Amgen Inc., Thousand Oaks, CA 91320-1789, USA.
| | | | | |
Collapse
|
109
|
Stenn KS, Combates NJ, Eilertsen KJ, Gordon JS, Pardinas JR, Parimoo S, Prouty SM. Hair follicle growth controls. Dermatol Clin 1996; 14:543-58. [PMID: 9238315 DOI: 10.1016/s0733-8635(05)70383-1] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Research in hair biology has embarked in the pursuit for molecules that control hair growth. Many molecules already have been associated with the controls of hair patterning, hair maturation, and hair cycling and differentiation. Knowing how these molecules work gives us the tools for understanding and treating patients with hair disorders.
Collapse
Affiliation(s)
- K S Stenn
- Skin Biology Research Center, Johnson & Johnson, Skillman, New Jersey, USA
| | | | | | | | | | | | | |
Collapse
|