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Cuevas-Diaz Duran R, Martinez-Ledesma E, Garcia-Garcia M, Bajo Gauzin D, Sarro-Ramírez A, Gonzalez-Carrillo C, Rodríguez-Sardin D, Fuentes A, Cardenas-Lopez A. The Biology and Genomics of Human Hair Follicles: A Focus on Androgenetic Alopecia. Int J Mol Sci 2024; 25:2542. [PMID: 38473791 DOI: 10.3390/ijms25052542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/16/2024] [Accepted: 02/18/2024] [Indexed: 03/14/2024] Open
Abstract
Androgenetic alopecia is a highly prevalent condition mainly affecting men. This complex trait is related to aging and genetics; however, multiple other factors, for example, lifestyle, are also involved. Despite its prevalence, the underlying biology of androgenetic alopecia remains elusive, and thus advances in its treatment have been hindered. Herein, we review the functional anatomy of hair follicles and the cell signaling events that play a role in follicle cycling. We also discuss the pathology of androgenetic alopecia and the known molecular mechanisms underlying this condition. Additionally, we describe studies comparing the transcriptional differences in hair follicles between balding and non-balding scalp regions. Given the genetic contribution, we also discuss the most significant risk variants found to be associated with androgenetic alopecia. A more comprehensive understanding of this pathology may be generated through using multi-omics approaches.
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Affiliation(s)
- Raquel Cuevas-Diaz Duran
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey 64710, NL, Mexico
- CapilarFix®, Monterrey 66220, NL, Mexico
| | - Emmanuel Martinez-Ledesma
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey 64710, NL, Mexico
- Tecnologico de Monterrey, Institute for Obesity Research, Monterrey 64849, NL, Mexico
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Xu K, Yu E, Wu M, Wei P, Yin J. Cells, growth factors and biomaterials used in tissue engineering for hair follicles regeneration. Regen Ther 2022; 21:596-610. [DOI: 10.1016/j.reth.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/26/2022] [Accepted: 11/08/2022] [Indexed: 11/27/2022] Open
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3
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Fatima I, Chen G, Botchkareva NV, Sharov AA, Thornton D, Wilkinson HN, Hardman MJ, Grutzkau A, Pedro de Magalhaes J, Seluanov A, Smith ESJ, Gorbunova V, Mardaryev AN, Faulkes CG, Botchkarev VA. Skin Aging in Long-Lived Naked Mole-Rats Is Accompanied by Increased Expression of Longevity-Associated and Tumor Suppressor Genes. J Invest Dermatol 2022; 142:2853-2863.e4. [PMID: 35691364 PMCID: PMC9613526 DOI: 10.1016/j.jid.2022.04.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 10/31/2022]
Abstract
Naked mole-rats (NMRs) (Heterocephalus glaber) are long-lived mammals that possess a natural resistance to cancer and other age-related pathologies, maintaining a healthy life span >30 years. In this study, using immunohistochemical and RNA-sequencing analyses, we compare skin morphology, cellular composition, and global transcriptome signatures between young and aged (aged 3‒4 vs. 19‒23 years, respectively) NMRs. We show that similar to aging in human skin, aging in NMRs is accompanied by a decrease in epidermal thickness; keratinocyte proliferation; and a decline in the number of Merkel cells, T cells, antigen-presenting cells, and melanocytes. Similar to that in human skin aging, expression levels of dermal collagens are decreased, whereas matrix metalloproteinase 9 and matrix metalloproteinase 11 levels increased in aged versus in young NMR skin. RNA-sequencing analyses reveal that in contrast to human or mouse skin aging, the transcript levels of several longevity-associated (Igfbp3, Igf2bp3, Ing2) and tumor-suppressor (Btg2, Cdkn1a, Cdkn2c, Dnmt3a, Hic1, Socs3, Sfrp1, Sfrp5, Thbs1, Tsc1, Zfp36) genes are increased in aged NMR skin. Overall, these data suggest that specific features in the NMR skin aging transcriptome might contribute to the resistance of NMRs to spontaneous skin carcinogenesis and provide a platform for further investigations of NMRs as a model organism for studying the biology and disease resistance of human skin.
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Affiliation(s)
- Iqra Fatima
- Centre for Skin Sciences, Faculty of Life Sciences, University of Bradford, Bradford, United Kingdom
| | - Guodong Chen
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Natalia V Botchkareva
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Andrey A Sharov
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Daniel Thornton
- Genomics of Aging and Rejuvenation Laboratory, Institute of Life Course and Medical Sciences, Univeristy of Liverpool, Liverpool, United Kingdom
| | - Holly N Wilkinson
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Matthew J Hardman
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Andreas Grutzkau
- Deutsches Rheuma-Forschungszentrum Berlin, Institute of the Leibniz Association, Berlin, Germany
| | - Joao Pedro de Magalhaes
- Genomics of Aging and Rejuvenation Laboratory, Institute of Life Course and Medical Sciences, Univeristy of Liverpool, Liverpool, United Kingdom
| | - Andrei Seluanov
- Department of Biology, School of Arts & Sciences, University of Rochester, Rochester, New York, USA; Department of Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | - Ewan St J Smith
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Vera Gorbunova
- Department of Biology, School of Arts & Sciences, University of Rochester, Rochester, New York, USA; Department of Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | - Andrei N Mardaryev
- Centre for Skin Sciences, Faculty of Life Sciences, University of Bradford, Bradford, United Kingdom
| | - Chris G Faulkes
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Vladimir A Botchkarev
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA.
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Reawakening GDNF's regenerative past in mice and humans. Regen Ther 2022; 20:78-85. [PMID: 35509264 PMCID: PMC9043678 DOI: 10.1016/j.reth.2022.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 11/22/2022] Open
Abstract
The ability of an animal to regenerate lost tissue and body parts has obviously life-saving implications. Understanding how this ability became restricted or active in specific animal lineages will help us understand our own regeneration. According to phylogenic analysis, the glial cell line-derived neurotrophic factor (GDNF) signaling pathway, but not other family members, is conserved in axolotls, a salamander with remarkable regenerative capacity. Furthermore, comparing the pro-regenerative Spiny mouse to its less regenerative descendant, the House mouse, revealed that the GDNF signaling pathway, but not other family members, was induced in regenerating Spiny mice. According to GDNF receptor expression analysis, GDNF may promote hair follicle neogenesis – an important feature of skin regeneration – by determining the fate of dermal fibroblasts as part of new hair follicles. These findings support the idea that GDNF treatment will promote skin regeneration in humans by demonstrating the GDNF signaling pathway's ancestral and cellular nature. In pro-regenerative axolotls, the GDNF-GFR□1 signaling system is conserved. In pro-regenerative Spiny mice, the GDNF-GFR□1 signaling system is activated. In mice, GDNF targets upper-regeneration-competent dermal fibroblasts. GDNF-GFR□1 activation may promote skin regeneration in mice and humans.
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Senna MM, Peterson E, Jozic I, Chéret J, Paus R. Frontiers in Lichen Planopilaris and Frontal Fibrosing Alopecia Research: Pathobiology Progress and Translational Horizons. JID INNOVATIONS 2022; 2:100113. [PMID: 35521043 PMCID: PMC9062486 DOI: 10.1016/j.xjidi.2022.100113] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/21/2022] [Accepted: 01/26/2022] [Indexed: 01/06/2023] Open
Abstract
Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are primary, lymphocytic cicatricial hair loss disorders. These model epithelial stem cell (SC) diseases are thought to result from a CD8+ T-cell‒dominated immune attack on the hair follicle (HF) SC niche (bulge) after the latter has lost its immune privilege (IP) for as yet unknown reasons. This induces both apoptosis and pathological epithelial‒mesenchymal transition in epithelial SCs, thus depletes the bulge, causes fibrosis, and ultimately abrogates the HFs' capacity to regenerate. In this paper, we synthesize recent progress in LPP and FFA pathobiology research, integrate our limited current understanding of the roles that genetic, hormonal, environmental, and other factors may play, and define major open questions. We propose that LPP and FFA share a common initial pathobiology, which then bifurcates into two distinct clinical phenotypes, with macrophages possibly playing a key role in phenotype determination. As particularly promising translational research avenues toward direly needed progress in the management of these disfiguring, deeply distressful cicatricial alopecia variants, we advocate to focus on the development of bulge IP and epithelial SC protectants such as, for example, topically effective, HF‒penetrating and immunoinhibitory preparations that contain tacrolimus, peroxisome proliferator-activated receptor-γ, and/or CB1 agonists.
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Key Words
- 5ARI, 5α-reductase inhibitor
- AA, alopecia areata
- AGA, androgenetic alopecia
- CRH, corticotropin-releasing hormone
- EMT, epithelial‒mesenchymal transition
- FFA, frontal fibrosing alopecia
- HF, hair follicle
- IP, immune privilege
- K, keratin
- KC, keratinocyte
- LPP, lichen planopilaris
- MAC, macrophage
- MHC, major histocompatibility complex
- PCA, primary cicatricial alopecia
- PCP, personal care product
- PPAR-γ, peroxisome proliferator–activated receptor-γ
- SC, stem cell
- SP, substance P
- eHFSC, epithelial hair follicle stem cell
- α-MSH, α-melanocyte-stimulating hormone
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Affiliation(s)
- Maryanne Makredes Senna
- Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Erik Peterson
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Ivan Jozic
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Jérémy Chéret
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Ralf Paus
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Monasterium Laboratory, Münster, Germany.,CUTANEON, Hamburg, Germany
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Vishlaghi N, Rieger S, McGaughey V, Lisse TS. GDNF neurotrophic factor signaling determines the fate of dermal fibroblasts in wound-induced hair neogenesis and skin regeneration. Exp Dermatol 2022; 31:577-581. [PMID: 35020233 PMCID: PMC9306530 DOI: 10.1111/exd.14526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 11/24/2021] [Accepted: 01/08/2022] [Indexed: 11/27/2022]
Abstract
We propose that GDNF, a glial cell line‐derived neurotrophic factor, can promote hair follicle neogenesis and skin regeneration after wounding by directing the fate of dermal fibroblasts. Our hypothesis is largely based on detailed GDNF and receptor analysis during skin regenerative stages, as well as the induction of GDNF receptors after wounding between the pro‐regenerative spiny mouse (genus Acomys) and its less‐regenerative descendant, the house mouse (Mus musculus). To characterize the GDNF‐target cells, we will conduct a series of lineage‐tracing experiments in conjunction with single‐cell RNA and assay for transposase‐accessible chromatin sequencing experiments. The heterogenetic dynamics of skin regeneration have yet to be fully defined, and this research will help to advance the fields of regenerative medicine and biology. Finally, we believe that stimulating the GDNF signalling pathway in fibroblasts from less‐regenerative animals, such as humans, will promote skin regeneration, morphogenesis and scarless wound healing.
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Affiliation(s)
- Neda Vishlaghi
- University of Miami, Biology Department, 1301 Memorial Drive, Cox Science Center, Coral Gables, FL, USA
| | - Sandra Rieger
- University of Miami, Biology Department, 1301 Memorial Drive, Cox Science Center, Coral Gables, FL, USA.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Vanessa McGaughey
- University of Miami, Biology Department, 1301 Memorial Drive, Cox Science Center, Coral Gables, FL, USA
| | - Thomas S Lisse
- University of Miami, Biology Department, 1301 Memorial Drive, Cox Science Center, Coral Gables, FL, USA.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, USA
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Effects of the selective TrkA agonist gambogic amide on pigmentation and growth of human hair follicles in vitro. PLoS One 2019; 14:e0221757. [PMID: 31465471 PMCID: PMC6715186 DOI: 10.1371/journal.pone.0221757] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 08/14/2019] [Indexed: 12/20/2022] Open
Abstract
The human hair follicle is a neuroendocrine mini-organ that can be used to study aging processes in vitro. Neurotrophins maintain homeostasis in hair biology via the Trk-family of receptors. TrkA, the high affinity receptor for nerve growth factor (NGF), is expressed in hair follicle melanocytes and keratinocytes, where it regulates proliferation, differentiation and apoptosis and may thereby play a role in hair pigmentation and growth. We investigated TrkA expression during the human hair cycle and the effects of a selective high affinity TrkA agonist, Gambogic Amide, on hair pigmentation and hair growth in human hair follicles in vitro. In human scalp skin, TrkA expression was strongest in proliferating melanocytes re-establishing the pigmentary unit in the hair bulb during the early hair growth phase, anagen. During high anagen and in the de-composing pigmentary-unit of the regression phase, catagen, bulb-melanocytes lost TrkA expression and only undifferentiated outer root sheath melanocytes maintained it. In cultured human anagen hair follicles, Gambogic Amide was able to prevent gradual pigment loss, while it stimulated hair shaft elongation. This was achieved by increased melanocyte activation, migration and dendricity, highlighted by distinct c-KIT-expression in melanocyte sub-populations. Our results suggest that Gambogic Amide can maintain hair follicle pigmentation by acting on undifferentiated melanocytes residing in the outer root sheath and making them migrate to establish the pigmentary-unit. This suggests that the selective TrkA agonist Gambogic Amide acts as an anti-hair greying and hair growth promoting molecule in vitro.
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8
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A genomic approach to susceptibility and pathogenesis leads to identifying potential novel therapeutic targets in androgenetic alopecia. Genomics 2017; 109:165-176. [DOI: 10.1016/j.ygeno.2017.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 02/03/2017] [Accepted: 02/25/2017] [Indexed: 02/07/2023]
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9
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Evaluation of Gene Expression Patterns in Micrografts Demonstrate Induction of Catagen-Like Processes During Storage. Dermatol Surg 2017; 43:275-280. [DOI: 10.1097/dss.0000000000000971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Ostrowski SM, Wright MC, Bolock AM, Geng X, Maricich SM. Ectopic Atoh1 expression drives Merkel cell production in embryonic, postnatal and adult mouse epidermis. Development 2015; 142:2533-44. [PMID: 26138479 DOI: 10.1242/dev.123141] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 06/04/2015] [Indexed: 12/18/2022]
Abstract
Merkel cells are mechanosensitive skin cells whose production requires the basic helix-loop-helix transcription factor Atoh1. We induced ectopic Atoh1 expression in the skin of transgenic mice to determine whether Atoh1 was sufficient to create additional Merkel cells. In embryos, ectopic Atoh1 expression drove ectopic expression of the Merkel cell marker keratin 8 (K8) throughout the epidermis. Epidermal Atoh1 induction in adolescent mice similarly drove widespread K8 expression in glabrous skin of the paws, but in the whisker pads and body skin ectopic K8+ cells were confined to hair follicles and absent from interfollicular regions. Ectopic K8+ cells acquired several characteristics of mature Merkel cells in a time frame similar to that seen during postnatal development of normal Merkel cells. Although ectopic K8+ cell numbers decreased over time, small numbers of these cells remained in deep regions of body skin hair follicles at 3 months post-induction. In adult mice, greater numbers of ectopic K8+ cells were created by Atoh1 induction during anagen versus telogen and following disruption of Notch signaling by conditional deletion of Rbpj in the epidermis. Our data demonstrate that Atoh1 expression is sufficient to produce new Merkel cells in the epidermis, that epidermal cell competency to respond to Atoh1 varies by skin location, developmental age and hair cycle stage, and that the Notch pathway plays a key role in limiting epidermal cell competency to respond to Atoh1 expression.
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Affiliation(s)
- Stephen M Ostrowski
- Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Margaret C Wright
- Center for Neurosciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Alexa M Bolock
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Xuehui Geng
- Richard King Mellon Institute for Pediatric Research, Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Stephen M Maricich
- Richard King Mellon Institute for Pediatric Research, Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA 15224, USA
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11
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Chéret J, Lebonvallet N, Carré JL, Misery L, Le Gall-Ianotto C. Role of neuropeptides, neurotrophins, and neurohormones in skin wound healing. Wound Repair Regen 2013; 21:772-88. [PMID: 24134750 DOI: 10.1111/wrr.12101] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 07/01/2013] [Indexed: 12/01/2022]
Abstract
Due to the close interactions between the skin and peripheral nervous system, there is increasing evidence that the cutaneous innervation is an important modulator of the normal wound healing process. The communication between sensory neurons and skin cells involves a variety of molecules (neuropeptides, neurohormones, and neurotrophins) and their specific receptors expressed by both neuronal and nonneuronal skin cells. It is well established that neurotransmitters and nerve growth factors released in skin have immunoregulatory roles and can exert mitogenic actions; they could also influence the functions of the different skin cell types during the wound healing process.
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Affiliation(s)
- Jérémy Chéret
- Laboratory of Neurosciences of Brest (EA4685), University of Western Brittany, Brest, France
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12
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Panchaprateep R, Korkij W, Asawanonda P. Brain-derived nerve factor and neurotrophins in androgenetic alopecia. Br J Dermatol 2011; 165:997-1002. [PMID: 21729031 DOI: 10.1111/j.1365-2133.2011.10514.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Several growth factors and cytokines have been shown to be involved in normal hair cycling as well as in androgenetic alopecia (AGA). However, the molecular cascades in AGA downstream from androgen receptor activation are far from being fully elucidated. OBJECTIVES We sought to determine the difference in the protein expression of growth factors/cytokines in balding vs. nonbalding scalp specimens from the same individuals affected with AGA. METHODS Balding and nonbalding scalp specimens were collected from four men with pattern baldness. Dermal papilla (DP) cells were isolated and cultured. Quantifying the protein expression of growth factors and cytokines expressed by these cells was performed using Quantibody® Human Growth Factor Array-1 (RayBiotech, Inc., Norcross, GA, U.S.A.). RESULTS Brain-derived nerve factor (BDNF) protein expression was upregulated by approximately 12-fold in supernatants obtained from balding as compared with nonbalding DP cells (P < 0·001). Expression of neurotrophin-3 and of β-nerve growth factor was also upregulated. On the other hand, protein expression of insulin-like growth factor-1 and its binding proteins as well as of the vascular endothelial growth factor family were significantly downregulated in the balding scalp. CONCLUSIONS Neurotrophic factors, especially BDNF, may be important in mediating the effects of androgens on hair follicles, serving as a negative regulatory control signal. Further studies may lead to novel pharmacological interventions in AGA.
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Affiliation(s)
- R Panchaprateep
- Division of Dermatology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
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13
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Hasegawa H, Wang F. Visualizing mechanosensory endings of TrkC-expressing neurons in HS3ST-2-hPLAP mice. J Comp Neurol 2008; 511:543-56. [PMID: 18839409 DOI: 10.1002/cne.21862] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Somatosensory neurons are classified into three main types according to their modalities: nociceptive, thermal, and mechanosensory. Within each modality group, neurons can be further divided into morphologically and functionally distinct subclasses. Here we show that heparan sulfate D-glucosaminyl 3-O-sulfotransferase 2 (HS3ST-2) is a marker for specific subsets of TrkC-expressing cutaneous low-threshold mechanosensory and proprioceptive mechanosensory neurons. Two-color in situ analysis revealed that almost all HS3ST-2 signals colocalized with TrkC but not with TrkA or TrkB mRNA. To visualize the morphological subtypes of HS3ST-2/TrkC-expressing neurons, we generated a HS3ST-2-hPLAP knock-in mouse line, in which HS3ST-2-expressing neurons and their projections are labeled by human placental alkaline phosphatase (hPLAP). AP staining in these mice demonstrated that sensory endings of muscle spindles and Golgi tendon organs as well as the cutaneous mechanosensory Merkel and longitudinal lanceolate endings in the whiskers are strongly positive for hPLAP activity. In contrast, no nociceptive endings are labeled. In the glabrous and hairy skin, rare Merkel endings and transverse lanceolate endings are weakly stained. During development, each type of nerve endings forms at different time point. Muscle innervations differentiate first, followed by formation of cutaneous sensory endings. Our results revealed the subtype identities of TrkC-positive mechanosensory neurons and demonstrated the usefulness of HS3ST-2 as a genetic marker for these subclasses of neurons.
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Affiliation(s)
- Hiroshi Hasegawa
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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14
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Fernandes KJ, Toma JG, Miller FD. Multipotent skin-derived precursors: adult neural crest-related precursors with therapeutic potential. Philos Trans R Soc Lond B Biol Sci 2008; 363:185-98. [PMID: 17282990 PMCID: PMC2605494 DOI: 10.1098/rstb.2006.2020] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We previously made the surprising finding that cultures of multipotent precursors can be grown from the dermis of neonatal and adult mammalian skin. These skin-derived precursors (SKPs) display multi-lineage differentiation potential, producing both neural and mesodermal progeny in vitro, and are an apparently novel precursor cell type that is distinct from other known precursors within the skin. In this review, we begin by placing these findings within the context of the rapidly evolving stem cell field. We then describe our recent efforts focused on understanding the developmental biology of SKPs, discussing the idea that SKPs are neural crest-related precursors that (i) migrate into the skin during embryogenesis, (ii) persist within a specific dermal niche, and (iii) play a key role in the normal physiology, and potentially pathology, of the skin. We conclude by highlighting some of the therapeutic implications and unresolved questions raised by these studies.
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Affiliation(s)
- Karl J.L Fernandes
- Programs in Developmental Biology, University of TorontoToronto, Ontario, Canada M5G 1X8
- Programs in Cancer Research, University of TorontoToronto, Canada M5G 1X8
| | - Jean G Toma
- Programs in Developmental Biology, University of TorontoToronto, Ontario, Canada M5G 1X8
| | - Freda D Miller
- Programs in Developmental Biology, University of TorontoToronto, Ontario, Canada M5G 1X8
- Programs in Brain and Behaviour, University of TorontoToronto, Canada M5G 1X8
- Department of Molecular and Medical Genetics, University of TorontoToronto, Canada M5G 1X8
- Department of Physiology, University of TorontoToronto, Canada M5G 1X8
- Author for correspondence ()
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15
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McIlwrath SL, Lawson JJ, Anderson CE, Albers KM, Koerber HR. Overexpression of neurotrophin-3 enhances the mechanical response properties of slowly adapting type 1 afferents and myelinated nociceptors. Eur J Neurosci 2008; 26:1801-12. [PMID: 17897394 DOI: 10.1111/j.1460-9568.2007.05821.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Constitutive overexpression of neurotrophin-3 (NT3) in murine skin results in an increased number of sensory neurons within the dorsal root ganglia, an increase of myelinated axons in cutaneous nerves, hyperinnervation of the skin, and an increased number of Merkel cells found in flank skin. Here we used a saphenous skin/nerve preparation to determine if these anatomical changes affect the functional response characteristics of cutaneous sensory neurons. Overexpression of NT3 significantly increased the responses of slowly adapting type 1 (SA1) low-threshold mechanoreceptors and Adelta high-threshold mechanoreceptors to suprathreshold mechanical stimulation. It also resulted in significantly faster conduction velocities of SA1 fibers. In contrast to earlier findings in flank skin, no differences were noted in the numbers of Merkel cells in the touch domes in hindlimb skin of NT3-overexpressing mice. In addition, the number of dermal Merkel cells, located around hair follicles on the dorsum of the foot, was reduced by 55%. The increase in mechanical sensitivity was found to correlate with significant increases in the expression of acid-sensing ion channels (ASIC) 1 and 3. Additional experiments using intracellular recordings and staining procedures confirmed that at least some cutaneous myelinated nociceptors and SA1 mechanoreceptors stained positively for both trkC and ASIC3. These results indicate that cutaneous NT3 overexpression alters the response properties of specific cutaneous sensory neurons, and that these changes may be due to the modulation of putative mechanosensitive ion channels.
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Affiliation(s)
- Sabrina L McIlwrath
- Department of Neurobiology, School of Medicine, University of Pittsburgh, 3500 Terrace St, Pittsburgh, PA 15261, USA
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16
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Abstract
For many decades, androgens have dominated endocrine research in hair growth control. Androgen metabolism and the androgen receptor currently are the key targets for systemic, pharmacological hair growth control in clinical medicine. However, it has long been known that estrogens also profoundly alter hair follicle growth and cycling by binding to locally expressed high-affinity estrogen receptors (ERs). Besides altering the transcription of genes with estrogen-responsive elements, 17beta-estradiol (E2) also modifies androgen metabolism within distinct subunits of the pilosebaceous unit (i.e., hair follicle and sebaceous gland). The latter displays prominent aromatase activity, the key enzyme for androgen conversion to E2, and is both an estrogen source and target. Here, we chart the recent renaissance of estrogen research in hair research; explain why the hair follicle offers an ideal, clinically relevant test system for studying the role of sex steroids, their receptors, and interactions in neuroectodermal-mesodermal interaction systems in general; and illustrate how it can be exploited to identify novel functions and signaling cross talks of ER-mediated signaling. Emphasizing the long-underestimated complexity and species-, gender-, and site-dependence of E2-induced biological effects on the hair follicle, we explore targets for pharmacological intervention in clinically relevant hair cycle manipulation, ranging from androgenetic alopecia and hirsutism via telogen effluvium to chemotherapy-induced alopecia. While defining major open questions, unsolved clinical challenges, and particularly promising research avenues in this area, we argue that the time has come to pay estrogen-mediated signaling the full attention it deserves in future endocrinological therapy of common hair growth disorders.
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Affiliation(s)
- Ulrich Ohnemus
- Department of Dermatology, University Hospital Schleswig-Holstein, Campus Lübeck, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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Botchkarev VA, Yaar M, Peters EMJ, Raychaudhuri SP, Botchkareva NV, Marconi A, Raychaudhuri SK, Paus R, Pincelli C. Neurotrophins in Skin Biology and Pathology. J Invest Dermatol 2006; 126:1719-27. [PMID: 16845411 DOI: 10.1038/sj.jid.5700270] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Neurotrophins (NTs) belong to a family of growth factors, which control the development, maintenance, and apoptotic death of neurons and also fulfill multiple regulatory functions outside the nervous system. Biological effects induced by NTs strongly depend on the pattern of NT receptor/co-receptors expression in target cells, as well as on the set of intracellular adaptor molecules that link NT signalling to distinct biochemical pathways. In this review, we summarize data on the molecular mechanisms underlying the involvement of NTs in the control of non-neuronal functions in normal skin (e.g. keratinocyte proliferation, melanocyte development and apoptosis, hair growth). We also review the data on the role for NTs and their receptors in a number of pathological skin conditions (stress-induced hair loss, psoriasis, atopic dermatitis). Although additional efforts are required to fully understand mechanisms underlying the involvement of NTs and their receptors in controlling functions of normal and pathologically altered skin cells, substantial evidence suggests that modulation of NT signalling by NTs receptor agonists/antagonists may be developed as intervention modalities in distinct skin and hair growth pathologies.
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Affiliation(s)
- Vladimir A Botchkarev
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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18
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Adly MA, Assaf HA, Nada EA, Soliman M, Hussein M. Human scalp skin and hair follicles express neurotrophin-3 and its high-affinity receptor tyrosine kinase C, and show hair cycle-dependent alterations in expression. Br J Dermatol 2005; 153:514-20. [PMID: 16120135 DOI: 10.1111/j.1365-2133.2005.06763.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Neurotrophin (NT)-3 and its high-affinity receptor tyrosine kinase C (Trk C) are essential for nervous system development. These members of the NT family are also involved in murine hair morphogenesis and cycling. However, their role in human hair follicle (HF) biology remains to be elucidated. OBJECTIVES To explore the role of NTs in human skin and HF biology. METHODS The immunoreactivity (IR) of NT-3 and Trk C was studied in human scalp skin and HFs by immunofluorescent and light microscopic immunohistology. Skin biopsies were obtained from normal human scalp containing mainly anagen VI HFs from women (age 53-57 years) undergoing elective plastic surgery. RESULTS Both NT-3 and Trk C showed prominent, yet distinct, IR patterns in human scalp anagen HFs (anagen VI), whereas they were weakly expressed in catagen and increased again in telogen HFs. Within HF compartments, NT-3 IR was prominent in the outer root sheath, inner root sheath, dermal papilla and connective tissue sheath. Trk C IR was prominent in all HF epithelial and mesenchymal compartments. Outside the HF, both NT-3 and Trk C showed prominent IR in the epidermis, sebaceous glands and sweat glands. CONCLUSIONS These observations provide the first indication that NT-3 and Trk C are expressed in human scalp skin and HFs, and suggest that Trk C-mediated signalling is involved not only in murine but also in human HF biology. They may be useful in determining therapeutic strategies for the treatment of hair cycle and skin-related disorders.
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Affiliation(s)
- M A Adly
- Department of Zoology, Sohag Faculty of Science, South Valley University, Sohag, Egypt
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19
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Abstract
The hair follicle, a unique characteristic of mammals, represents a stem cell-rich, prototypic neuroectodermal-mesodermal interaction system. This factory for pigmented epithelial fibers is unique in that it is the only organ in the mammalian body which, for its entire lifetime, undergoes cyclic transformations from stages of rapid growth (anagen) to apoptosis-driven regression (catagen) and back to anagen, via an interspersed period of relative quiescence (telogen). While it is undisputed that the biological "clock" that drives hair follicle cycling resides in the hair follicle itself, the molecular nature of the underlying oscillator system remains to be clarified. To meet this challenge is of profound general interest, since numerous key problems of modern biology can be studied exemplarily in this versatile model system. It is also clinically important, since the vast majority of patients with hair growth disorders suffers from an undesired alteration of hair follicle cycling. Here, we sketch basic background information and key concepts that one needs to keep in mind when exploring the enigmatic "hair cycle clock"(HCC), and summarize competing models of the HCC. We invite the reader on a very subjective guided tour, which focuses on our own trials, errors, and findings toward the distant goal of unravelling one of the most fascinating mysteries of biology: Why does the hair follicle cycle at all? How does it do it? What are the key players in the underlying molecular controls? Attempting to offer at least some meaningful answers, we share our prejudices and perspectives, and define crucial open questions.
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Affiliation(s)
- Ralf Paus
- Department of Dermatology, University Hospital Hamburg-Eppendorf, University of Hamburg, Martinistr. 52, D-20426 Hamburg, Germany.
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20
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Abstract
Hair follicle (HF) development is the result of neuroectodermal-mesodermal interactions, and can be divided into morphologically distinguishable stages (induction, organogenesis and cytodifferentiation). The spacing, polarity and differentiation patterns of HFs are driven by interacting, self-assembling gradients of inhibitors and activators, which are established jointly by the skin epithelium and mesenchyme. For HF development to occur, the dominant-negative influence of inhibitors of the HF differentiation pathway must be locally counteracted by specific antagonists and/or overriden by stimulators of hair placode formation. Once a mesenchymal condensate of inductive fibroblasts has formed, it takes over control of most subsequent steps of HF organogenesis and of epithelial stem cell differentiation into distinct lineages. In this review we introduce the morphological characteristics, major underlying principles and molecular key players that control HF development. The focus is on recent insights into the molecular interactions leading to hair follicle induction, and we close with synthesizing a corresponding working hypothesis.
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Affiliation(s)
- Ruth Schmidt-Ullrich
- Department of Cell Growth and Differentiation, Max-Delbrück-Center for Molecular Medicine, Berlin-Buch, Germany
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21
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Peters EMJ, Hansen MG, Overall RW, Nakamura M, Pertile P, Klapp BF, Arck PC, Paus R. Control of Human Hair Growth by Neurotrophins: Brain-Derived Neurotrophic Factor Inhibits Hair Shaft Elongation, Induces Catagen, and Stimulates Follicular Transforming Growth Factor β2 Expression. J Invest Dermatol 2005; 124:675-85. [PMID: 15816823 DOI: 10.1111/j.0022-202x.2005.23648.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neurotrophins are important modulators of epithelial-mesenchymal interactions. Previously, we had shown that brain-derived neurotrophic factor (BDNF) and its high-affinity receptor tyrosine kinase B (TrkB) are prominently involved in the control of murine hair follicle cycling. We now show that BDNF and TrkB are also expressed in the human hair follicle in a manner that is both hair cycle dependent and suggestive of epithelial-mesenchymal cross-talk between BDNF-secreting dermal papilla fibroblasts of anagen hair follicles and subpopulations of TrkB+ hair follicle keratinocytes. As functional evidence for an involvement of BDNF/TrkB in human hair growth control, we show in organ-cultured human anagen hair follicles that 50 ng per mL BDNF significantly inhibit hair shaft elongation, induce premature catagen development, and inhibit keratinocyte proliferation. Quantitative real-time rtPCR analysis demonstrates upregulation of the potent catagen inducer, transforming growth factor beta2 (TGFbeta2) by BDNF, whereas catagen induction by BDNF was partially reversible through co-administration of TGFbeta-neutralizing antibody. This suggests that TrkB-mediated signaling promotes the switch between anagen and catagen at least in part via upregulation of TGFbeta2. Thus, human scalp hair follicles are both a source and target of bioregulation by BDNF, which invites to target TrkB-mediated signaling for therapeutic hair growth modulation.
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Affiliation(s)
- Eva M J Peters
- Department of Internal Medicine, Biomedical Research Center, University Medicine Charité, Campus Virchow Hospital, Berlin, Germany.
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22
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Yang WB, Hao F, Song ZQ, Yang XC, Ni B. Apoptosis of the dermal papilla cells of hair follicle associated with the expression of gene HSPCO16 in vitro. Exp Dermatol 2005; 14:209-14. [PMID: 15740594 DOI: 10.1111/j.0906-6705.2005.00268.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The epithelial-mesenchymal interactions have an important role in the folliculomorphogenesis and mature hair follicle cycling. The dermal papilla, a dense aggregate of specialized dermis-derived stromal cells located at the bottom of the hair follicle, is a major component of hair, which signals the follicular epithelial cells to prolong the hair growth process. However, to date, little is known about the significance of the specific gene(s) expression in the dermal papilla cells with regard to their aggregative behaviour and hair cycling. In our previous study, the differentially gene-expressed cDNAs library had been determined by means of suppression subtractive hybridization technique between the aggregated human dermal papilla cells and control cells. Among those cDNAs library, the haematopoietic stem/progenitor cell (HSPC)-related gene HSPC016 was found. In this study, the gene HSPC016 was confirmed to express in the human dermal papilla cells by means of in situ hybridization and reverse transcriptase-polymerase chain reaction. In order to rudimentarily elucidate its biological function, a recombinant eucaryotic expressing plasmid pcDNA3.1(+)/HSPC016 was constructed and was transfected into the human dermal papilla cells and 3T3 fibroblast cells by means of Nucleofector(TM) technique (Amaxa, Cologne, Germany). Terminal deoxynucleotidyl transferase-mediated d-UTP nick end Labelling (TUNEL) assay showed that the expression of gene HSPCO16 resulted in the apoptosis of these cells, which suggested that the apoptosis of dermal papilla cells might be associated with the expression of gene HSPC016 in vitro.
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Affiliation(s)
- Wei B Yang
- Department of Dermatology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
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23
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Breugem CC, Hennekam RCM, van Gemert MJC, van der Horst CMAM. Are Capillary Malformations Neurovenular or Purely Neural? Plast Reconstr Surg 2005; 115:578-87. [PMID: 15692368 DOI: 10.1097/01.prs.0000150150.69479.70] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Corstiaan C Breugem
- Department of Plastic, Reconstructive, and Hand Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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24
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Chernyavsky AI, Arredondo J, Wess J, Karlsson E, Grando SA. Novel signaling pathways mediating reciprocal control of keratinocyte migration and wound epithelialization through M3 and M4 muscarinic receptors. ACTA ACUST UNITED AC 2004; 166:261-72. [PMID: 15263021 PMCID: PMC2172302 DOI: 10.1083/jcb.200401034] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To test the hypothesis that keratinocyte (KC) migration is modulated by distinct muscarinic acetylcholine (ACh) receptor subtypes, we inactivated signaling through specific receptors in in vitro and in vivo models of reepithelialization by subtype-selective antagonists, small interfering RNA, and gene knockout in mice. KC migration and wound reepithelialization were facilitated by M4 and inhibited by M3. Additional studies showed that M4 increases expression of "migratory" integrins alpha5beta1, alphaVbeta5, and alphaVbeta6, whereas M3 up-regulates "sedentary" integrins alpha2beta1 and alpha3beta1. Inhibition of migration by M3 was mediated through Ca2+-dependent guanylyl cyclase-cyclic GMP-protein kinase G signaling pathway. The M4 effects resulted from inhibition of the inhibitory pathway involving the adenylyl cyclase-cyclic AMP-protein kinase A pathway. Both signaling pathways intersected at Rho, indicating that Rho kinase provides a common effector for M3 and M4 regulation of cell migration. These findings offer novel insights into the mechanisms of ACh-mediated modulation of KC migration and wound reepithelialization, and may aid the development of novel methods to promote wound healing.
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Affiliation(s)
- Alex I Chernyavsky
- Deppartment of Dermatology, University of California, Davis, Sacramento, CA 95817, USA
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25
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Metz M, Botchkarev VA, Botchkareva NV, Welker P, Tobin DJ, Knop J, Maurer M, Paus R. Neurotrophin-3 regulates mast cell functions in neonatal mouse skin. Exp Dermatol 2004; 13:273-81. [PMID: 15140017 DOI: 10.1111/j.0906-6705.2004.00115.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Nerve growth factor (NGF) has long been recognized as an important mast cell (MC) growth factor. To explore whether other neurotrophins (NTs) of the NGF family, which are widely expressed in mouse skin, affect the numbers and/or functions of MCs we examined the effects of NT-3 on neonatal skin MCs. We demonstrate that TrkC, the high affinity NT-3 receptor, is expressed by virtually all neonatal skin MCs in C57BL/6 mice, which indicates that MCs can respond to NT-3. Skin of neonatal and early postnatal NT-3-overexpressing mice (promoter: K14) displayed significantly and up to twofold increased numbers of MCs during the first 20 days after birth, as compared to wild-type mice. To check whether this increase in MC numbers in NT-3 transgenic mice reflects a higher rate of proliferation, we performed immunohistochemistry, which revealed that only 1-2% of all skin MCs both in NT-3-overexpressing and in wild-type controls showed Ki-67-positive nuclei, suggesting that the observed differences in the number of MCs do not reflect a higher rate of MC proliferation. Additionally, we show that the effect of NT-3 on the number of MCs is most likely to be stem cell factor (SCF)-independent, because NT-3 significantly downregulates secretion of SCF-protein in cultured dermal fibroblasts, as assessed by enzyme-linked immunosorbent assay. Numbers of skin MCs in neonatal TrkC-deficient mice were found to be modestly reduced, as compared to wild-type mice, indicating that NT-3 can modulate the number of MCs directly via TrkC, although TrkC does not seem to be essential for the number of basal MCs. To further analyze the effects of NT-3 on MCs, we stimulated skin organ culture of early postnatal C57BL/6 mouse skin with 5-50 ng/ml NT-3, which induced a significant increase in MC degranulation, as visualized by Giemsa staining. However, stimulation of isolated neonatal dermal skin MCs with NT-3 in vitro failed to result in MC activation, as measured by serotonin release. Our data suggest a role for NT-3 in the maturation of MCs, such as a TrkC-mediated stimulation of the differentiation of pre-existing, less mature MCs and/or by enhancing the migration of circulating MC precursors into the skin.
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Affiliation(s)
- Martin Metz
- Department of Dermatology, University Hospital Mainz, Mainz, Germany
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26
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Sieber-Blum M, Szeder V, Grim M. The role of NT-3 signaling in Merkel cell development. PROGRESS IN BRAIN RESEARCH 2004; 146:63-72. [PMID: 14699956 DOI: 10.1016/s0079-6123(03)46004-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Merkel cells originate from the neural crest. They are located in hairy and glabrous skin and have neuroendocrine characteristics. Together with A beta afferents, Merkel cells form a slowly adapting mechanoreceptor, the Merkel nerve ending, which transduces steady skin indentation. Neurotphin-3 (NT-3) plays important roles in neural crest cell development. We thus sought to determine whether neurotrophin signaling is essential for Merkel cell development in the whisker pad of the mouse. Our data indicate that at embryonic day 16.5 (E 16.5), NT-3 and its receptors, p75 neurotrophin receptor (p75NTR) and tyrosine kinase receptor, TrkC are not expressed at detectable levels in Merkel cells. After a perinatal switch, however, Merkel cells in whiskers of newborn mice are immunoreactive for p75NTR, TrkC and NT-3. Immunoreactivity of all three markers persists into adulthood. By contrast, innervating fibers are intensely p75NTR-immunoreactive in E16.5 whiskers, but no TrkC immunoreactivity is detected. At birth, and at 6 weeks of age, afferent fibers are intensely immunoreactive for both p75NTR and TrkC. In TrkC null whiskers, numerous Merkel cells are present at E16.5, and they are innervated. We draw three major conclusions from these observations: (i) NT-3 signaling through p75NTR or TrkC is not required for the development and prenatal survival of either a major subset or of all Merkel cells, (ii) the postnatal survival of Merkel cells is supported by autocrine or paracrine NT-3, rather than by neuron-derived NT-3, and (iii) Merkel cell-derived NT-3 is not a chemoattractant for innervating A beta fibers, but is likely to be involved in maintaining Merkel cell innervation postnatally.
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Affiliation(s)
- Maya Sieber-Blum
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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27
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Szeder V, Grim M, Kucera J, Sieber-Blum M. Neurotrophin-3 signaling in mammalian Merkel cell development. Dev Dyn 2003; 228:623-9. [PMID: 14648839 DOI: 10.1002/dvdy.10403] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Merkel cells are sensory cells of neural crest origin. Because little is known about the mechanisms that direct their differentiation, we have investigated the potential role of a candidate regulatory factor, neurotrophin-3 (NT-3). At embryonic day 16.5 (E 16.5), neither NT-3 nor its primary receptors, TrkC and p75NTR are expressed by Merkel cells in the murine whisker. At the time of birth, however, Merkel cells are immunoreactive for NT-3, TrkC and p75NTR. In TrkC null and NT-3 null mice, Merkel cells differentiate initially, but undergo apoptosis perinatally. These results show that NT-3 signaling is not required for the differentiation of Merkel cells, but that it is essential for their postnatal survival.
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Affiliation(s)
- Viktor Szeder
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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28
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Nakamura M, Matzuk MM, Gerstmayer B, Bosio A, Lauster R, Miyachi Y, Werner S, Paus R. Control of pelage hair follicle development and cycling by complex interactions between follistatin and activin. FASEB J 2003; 17:497-9. [PMID: 12514121 DOI: 10.1096/fj.02-0247fje] [Citation(s) in RCA: 67] [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
Members of the transforming growth factor beta/bone morphogenetic protein (TGF-beta/BMP) family are involved in the control of hair follicle (HF) morphogenesis and cycling. The activities of several members of this family activins and BMP-2, -4, -7, and -11) are controlled by antagonists such as follistatin. Because follistatin-deficient mice show abnormalities in vibrissae development, we explored the role of follistatin and activin in pelage HF development and cycling. We show here that during HF development follistatin mRNA was prominently expressed by hair matrix and outer root sheath keratinocytes as well as by interfollicular epidermal cells, whereas activin betaA mRNA was mainly expressed in dermal papilla cells. Compared with age-matched wild-type controls, both follistatin knockout mice and activin betaA transgenic mice showed a significant retardation of HF morphogenesis. Treatment of wild-type embryonic skin explants with follistatin protein stimulated HF development. This effect was inhibited by addition of recombinant activin A protein. Activin betaA transgenic mice demonstrated retardation of catagen entry, down-regulation of BMP-2, and up-regulation of expression of its antagonist matrix GLA protein. These observations suggest that follistatin and activin interaction plays an important role in both HF development and cycling, possibly in part by regulating expression of BMP-2 and its antagonist.
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Affiliation(s)
- Motonobu Nakamura
- Department of Dermatology, University Hospital Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany
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29
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Haberberger RV, Pfeil U, Lips KS, Kummer W. Expression of the high-affinity choline transporter, CHT1, in the neuronal and non-neuronal cholinergic system of human and rat skin. J Invest Dermatol 2002; 119:943-8. [PMID: 12406342 DOI: 10.1046/j.1523-1747.2002.00182.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Choline is an essential component in acetylcholine biosynthesis, and is involved in cell signaling. It is unable to permeate the cell membrane and requires a transporter to enter the cell. Neurons that synthesize acetylcholine take up choline by a recently cloned high-affinity choline transporter (choline transporter 1) that is Na+-dependent and can be blocked by hemicholinium-3. The aim of this study was to determine the expression and to analyze the distribution of choline transporter 1 in human and rat skin. The mRNA for choline transporter 1 was detected in rat and human skin and in the human keratinocyte cell line HaCaT. A polyclonal anti-serum was developed against the N-terminal region of the human and rat protein. In rat and human skin, choline transporter 1 immunoreactivity was present in nerve fibers. In addition, keratinocytes, HaCaT cells and cells of the internal root sheath of the hair follicle contained choline transporter 1 immunoreactivity. The labeling patterns of nonconfluent vs confluent cultured cells and the distribution of choline transporter 1 along the epidermal layer suggest an association of choline transporter 1 with keratinocyte differentiation. In conclusion, this study shows the presence of the high-affinity choline transporter choline transporter 1 in nerve fibers and epithelial cells in the human and rat skin supporting the pivotal role of this transporter in both the neuronal and non-neuronal cholinergic system of the skin.
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30
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Peters EMJ, Botchkarev VA, Müller-Röver S, Moll I, Rice FL, Paus R. Developmental timing of hair follicle and dorsal skin innervation in mice. J Comp Neurol 2002; 448:28-52. [PMID: 12012374 DOI: 10.1002/cne.10212] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The innervation of hair follicles offers an intriguing, yet hardly studied model for the dissection of the stepwise innervation during cutaneous morphogenesis. We have used immunofluorescence and a panel of neuronal markers to characterize the developmental choreography of C57BL/6 mouse backskin innervation. The development of murine skin innervation occurs in successive waves. The first cutaneous nerve fibers appeared before any morphological evidence of hair follicle development at embryonic day 15 (E15). Stage 1 and 2 developing hair follicles were already associated with nerve fibers at E16. These fibers approached a location where later in development the follicular (neural) network A (FNA) is located on fully developed pelage hair follicles. Prior to birth (E18), some nerve fibers had penetrated the epidermis, and an additional set of perifollicular nerve fibers arranged itself around the isthmus and bulge region of stage 5 hair follicles, to develop into the follicular (neural) network B (FNB). By the day of birth (P1), the neuropeptides substance P and calcitonin gene-related peptide became detectable in subcutaneous and dermal nerve fibers first. Newly formed hair follicles on E18 and P1 displayed the same innervation pattern seen in the first wave of hair follicle development. Just prior to epidermal penetration of hair shafts (P5), peptide histidine methionine-IR nerve fibers became detectable and epidermal innervation peaked; such innervation decreased after penetration (P7- P17). Last, tyrosine hydroxylase-IR and neuropeptide Y-IR became readily detectable. This sequence of developing innervation consistently correlates with hair follicle development, indicating a close interdependence of neuronal and epithelial morphogenesis.
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Affiliation(s)
- Eva M J Peters
- Department of Dermatology, University Hospital Eppendorf, University of Hamburg, Hamburg D-20246, Germany
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31
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Abstract
Clinical conditions causing hair loss, such as androgenetic alopecia, alopecia areata, and scarring alopecia, can be psychologically devastating to individuals and are the target of a multimillion dollar pharmaceutical industry. The importance of the hair follicle in skin biology, however, does not rest solely with its ability to produce hair. Hair follicles are self-renewing and contain reservoirs of multipotent stem cells that are capable of regenerating the epidermis and are thought to be utilized in wound healing. Hair follicles are also the sites of origin of many neoplasias, including some basal cell carcinomas and pilomatricoma. These diseases result from inappropriate activation of signaling pathways that regulate hair follicle morphogenesis. Identification of the signaling molecules and pathways operating in developing and postnatal, cycling, hair follicles is therefore vital to our understanding of pathogenic states in the skin and may ultimately permit the development of novel therapies for skin tumors as well as for hair loss disease. The purpose of this review is to summarize recent progress in our understanding of the molecular mechanisms regulating hair follicle formation, and to discuss ways in which this information may eventually be utilized in the clinic.
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Affiliation(s)
- Sarah E Millar
- Department of Dermatology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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32
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Nakamura M, Sundberg JP, Paus R. Mutant laboratory mice with abnormalities in hair follicle morphogenesis, cycling, and/or structure: annotated tables. Exp Dermatol 2001; 10:369-90. [PMID: 11737257 DOI: 10.1034/j.1600-0625.2001.100601.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Numerous transgenic, targeted mutagenesis (so-called knockouts), conditional (so-called "gene switch") and spontaneous mutant mice develop abnormal hair phenotypes. The number of mice that exhibit such abnormalities is increasing exponentially as genetic engineering methods become routine. Since defined abnormalities in hair follicle morphogenesis, cycling and/or structure in such mutant mice provide important clues to the as yet poorly understood functional roles of many gene products, it is useful to summarize and classify these mutant mice according to their hair phenotype. This review provides a corresponding, annotated table of mutant mice with hair abnormalities, classifying the latter into 6 categories, 1) abnormally low number of hair follicles, 2) disorders of hair morphogenesis, 3) of hair follicle cycling, 4) of hair follicle structure 5) of sebaceous gland structure, and 6) hair growth disorders as a consequence of immunological abnormalities. This annotated table should serve as a useful source of reference for anyone who is interested in the molecular controls of hair growth, for investigators who are looking for mouse models to explore or compare the functional activities of their gene of interest, and for comparing the hair phenotype of newly generated mouse mutants with existing ones.
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Affiliation(s)
- M Nakamura
- Department of Dermatology, University Hospital Eppendorf, University of Hamburg, Martinistrasse 52, D-20246, Hamburg, Germany
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Ritter AM, Woodbury CJ, Davis BM, Albers K, Koerber HR. Excess target-derived neurotrophin-3 alters the segmental innervation of the skin. Eur J Neurosci 2001; 14:411-8. [PMID: 11553291 DOI: 10.1046/j.0953-816x.2001.01654.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
It is thought that dermatomes are established during development as a result of competition between afferents of neighbouring segments. Mice that overexpress neurotrophins in the skin provide an interesting model to test this hypothesis, as they possess increased numbers of sensory neurons, and display hyperinnervation of the skin. When dermatomal boundaries were mapped in adult mice, it was found that those in nerve growth factor and brain-derived neurotrophic factor overexpressers were indistinguishable from wild-type animals but that overlap between adjacent segments was greatly reduced in neurotrophin-3 (NT-3) overexpressers. However, dermatomes in heterozygous NT-3 knockout mice displayed no more overlap than wild-types. In order to quantify differences across strains, innervation territories of thoracic dorsal cutaneous nerves were mapped and measured in adult mice. Overlap between adjacent dorsal cutaneous nerves was normal in nerve growth factor overexpressing mice, but much reduced in NT-3 overexpressers. However, this restriction was not reflected in the central projection of the dorsal cutaneous nerve, creating a mismatch between peripheral and central projections. Dorsal cutaneous nerve territories were also mapped in neonatal mice aged postnatal day 7-8. In neonates, nerve territories of NT-3 overexpressers overlapped less than wild-types, but in neonates of both strains the amount of overlap was much greater than in the adult. These results indicate that substantial separation of dermatomes occurs postnatally, and that excess NT-3 enhances this process, resulting in more restricted dermatomes. It may exert its effects either by enhancing competition, or by direct effects on the stability and formation of sensory endings in the skin.
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Affiliation(s)
- A M Ritter
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261, USA.
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Magerl M, Tobin DJ, Müller-Röver S, Hagen E, Lindner G, McKay IA, Paus R. Patterns of proliferation and apoptosis during murine hair follicle morphogenesis. J Invest Dermatol 2001; 116:947-55. [PMID: 11407986 DOI: 10.1046/j.0022-202x.2001.01368.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this study, we have correlated cutaneous apoptosis and proliferation in neonatal mice during hair follicle morphogenesis. We have applied a novel triple- staining technique that uses Ki67 immunoreactivity as a marker of proliferation as well as TUNEL and Hoechst 33342 staining as apoptosis markers. We have also assessed the immunoreactivity of interleukin-1 beta-converting enzyme, caspase 1, a key enzyme in the execution of apoptosis, and of P-cadherin, which has been suggested as a key adhesion receptor in segregating proliferating keratinocytes. The TUNEL data were systematically compared with high resolution light microscopy and transmission electron microscopy data. Virtually all keratinocytes of the developing hair bud were strongly Ki67(+), suggesting that the hair bud is not an epidermal invagination but primarily the product of localized keratinocyte proliferation. As hair follicle development advanced, three distinct foci of proliferation became apparent: the distal outer root sheath around the hair canal, the mid outer root sheath, and the proximal hair matrix. Of these proliferating hair follicle keratinocytes only defined subsets expressed P-cadherin. TUNEL(+) cells in the hair follicle were not found before stage 5 of murine hair follicle morphogenesis. During the early stages of hair follicle development, interleukin-1 beta-converting enzyme immunoreactivity was present on all keratinocytes, but virtually disappeared from the proximal hair follicle epithelium later on. High resolution light microscopy/transmission electron microscopy revealed scattered and clustered apoptotic keratinocytes in all epithelial hair follicle compartments throughout hair follicle development, including its earliest stages. This highlights striking differences in the demarcation of apoptotic hair follicle keratinocytes between the TUNEL technique and high resolution light microscopy/transmission electron microscopy and suggests a role for apoptosis in sculpting the hair follicle even during early hair follicle development.
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Affiliation(s)
- M Magerl
- Department of Dermatology, Charité, Humboldt-University, Berlin, Germany
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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.
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Affiliation(s)
- K S Stenn
- Beauty Genome Sciences Inc., Skillman, New Jersey, USA.
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36
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Abstract
The classical observations of the skin as a target for melanotropins have been complemented by the discovery of their actual production at the local level. In fact, all of the elements controlling the activity of the hypothalamus-pituitary-adrenal axis are expressed in the skin including CRH, urocortin, and POMC, with its products ACTH, alpha-MSH, and beta-endorphin. Demonstration of the corresponding receptors in the same cells suggests para- or autocrine mechanisms of action. These findings, together with the demonstration of cutaneous production of numerous other hormones including vitamin D3, PTH-related protein (PTHrP), catecholamines, and acetylcholine that share regulation by environmental stressors such as UV light, underlie a role for these agents in the skin response to stress. The endocrine mediators with their receptors are organized into dermal and epidermal units that allow precise control of their activity in a field-restricted manner. The skin neuroendocrine system communicates with itself and with the systemic level through humoral and neural pathways to induce vascular, immune, or pigmentary changes, to directly buffer noxious agents or neutralize the elicited local reactions. Therefore, we suggest that the skin neuroendocrine system acts by preserving and maintaining the skin structural and functional integrity and, by inference, systemic homeostasis.
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Affiliation(s)
- A Slominski
- Department of Pathology ,University of Tennessee, Memphis 38163, USA.
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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.
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Affiliation(s)
- V A Botchkarev
- *Department of Dermatology, Charité, Humboldt University, Berlin, Germany
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38
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Roth W, Deussing J, Botchkarev VA, Pauly-Evers M, Saftig P, Hafner A, Schmidt P, Schmahl W, Scherer J, Anton-Lamprecht I, Von Figura K, Paus R, Peters C. Cathepsin L deficiency as molecular defect of furless: hyperproliferation of keratinocytes and pertubation of hair follicle cycling. FASEB J 2000; 14:2075-86. [PMID: 11023992 DOI: 10.1096/fj.99-0970com] [Citation(s) in RCA: 259] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lysosomal cysteine proteinases of the papain family are involved in lysosomal bulk proteolysis, major histocompatibility complex class II mediated antigen presentation, prohormone processing, and extracellular matrix remodeling. Cathepsin L (CTSL) is a ubiquitously expressed major representative of the papain-like family of cysteine proteinases. To investigate CTSL in vivo functions, the gene was inactivated by gene targeting in embryonic stem cells. CTSL-deficient mice develop periodic hair loss and epidermal hyperplasia, acanthosis, and hyperkeratosis. The hair loss is due to alterations of hair follicle morphogenesis and cycling, dilatation of hair follicle canals, and disturbed club hair formation. Hyperproliferation of hair follicle epithelial cells and basal epidermal keratinocytes-both of ectodermal origin-are the primary characteristics underlying the mutant phenotype. Pathological inflammatory responses have been excluded as a putative cause of the skin and hair disorder. The phenotype of CTSL-deficient mice is reminiscent of the spontaneous mouse mutant furless (fs). Analyses of the ctsl gene of fs mice revealed a G149R mutation inactivating the proteinase activity. CTSL is the first lysosomal proteinase shown to be essential for epidermal homeostasis and regular hair follicle morphogenesis and cycling.
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Affiliation(s)
- W Roth
- Institut für Molekulare Medizin und Zellforschung, Albert Ludwigs Universität Freiburg, 79106 Freiburg, Germany
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39
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Müller-Röver S, Rossiter H, Paus R, Handjiski B, Peters EM, Murphy JE, Mecklenburg L, Kupper TS. Overexpression of Bcl-2 protects from ultraviolet B-induced apoptosis but promotes hair follicle regression and chemotherapy-induced alopecia. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 156:1395-405. [PMID: 10751363 PMCID: PMC1876869 DOI: 10.1016/s0002-9440(10)65008-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/22/1999] [Indexed: 11/21/2022]
Abstract
Hair follicle (HF) growth and regression is an exquisitely regulated process of cell proliferation followed by massive cell death and is accompanied by cyclical expression of the apoptosis regulatory gene pair, Bcl-2 and Bax. To further investigate the role of Bcl-2 expression in the control of hair growth and keratinocyte apoptosis, we have used transgenic mice that overexpress human Bcl-2 in basal epidermis and in the outer root sheath under the control of the human keratin-14 promoter (K14/Bcl-2). When irradiated with ultraviolet B (UVB) light, K14/Bcl-2 mice developed about 5-10-fold fewer sunburn cells (ie, apoptotic keratinocytes) in the basal layer of the epidermis, compared to wild-type mice, whereas cultures of primary keratinocytes from transgenic mice were completely resistant to UVB-induced histone formation, at doses that readily induced histone release from wild-type cells. K14/Bcl-2 mice show no alteration of neonatal hair follicle morphogenesis or of the onset of the first wave of HF regression (catagen). However, compared to wild-type controls, K14/Bcl-2 mice subsequently displayed a significant acceleration of spontaneous catagen progression. During chemotherapy-induced alopecia, follicular dystrophy was promoted in K14/Bcl-2 mice. Thus, although K14-driven overexpression of Bcl-2 protected murine epidermal keratinocytes from UVB-induced apoptosis, it surprisingly promoted catagen- and chemotherapy-associated keratinocyte apoptosis.
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Affiliation(s)
- S Müller-Röver
- Harvard Skin Disease Research Center, Brigham and Womens Hospital, Boston, Massachusetts 02115, USA
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40
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Lindner G, Menrad A, Gherardi E, Merlino G, Welker P, Handjiski B, Roloff B, Paus R. Involvement of hepatocyte growth factor/scatter factor and met receptor signaling in hair follicle morphogenesis and cycling. FASEB J 2000; 14:319-32. [PMID: 10657988 DOI: 10.1096/fasebj.14.2.319] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
HGF/SF and its receptor (Met) are principal mediators of mesenchymal-epithelial interactions in several different systems and have recently been implicated in the control of hair follicle (HF) growth. We have studied their expression patterns during HF morphogenesis and cycling in C57BL/6 mice, whereas functional hair growth effects of HGF/SF were assessed in vivo by analysis of transgenic mice and in skin organ culture. In normal mouse skin, follicular expression of HGF/SF and Met was strikingly localized: HGF/SF was found only in the HF mesenchyme (dermal papilla fibroblasts) and Met in the neighboring hair bulb keratinocytes. Both HGF/SF and Met expression peaked during the initial phases of HF morphogenesis, the stage of active hair growth (early and mid anagen), and during the apoptosis-driven HF regression (catagen). Met+ cells in the regressing epithelial strand appeared to be protected from undergoing apoptosis. Compared to wild-type controls, transgenic mice overexpressing HGF/SF under the control of the MT-1 promoter had twice as many developing HF and displayed accelerated HF development on postnatal day 3. They also showed significant catagen retardation on P17. In organ culture and in vivo, HGF/SF i.c. resulted in a significant catagen retardation. These results demonstrate an important role of HGF/SF and Met in murine hair growth control and suggest that Met-mediated signaling might be exploited for therapeutic manipulation of human hair growth disorders.-Lindner, G., Menrad, A., Gherardi, E., Merlino, G., Welker, P., Handjiski, B., Roloff, B., Paus, R. Involvement of hepatocyte growth factor/scatter factor and Met receptor signaling in hair follicle morphogenesis and cycling.
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Affiliation(s)
- G Lindner
- Department of Dermatology, Charité, Humboldt-University, Berlin, Germany
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41
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Botchkareva NV, Botchkarev VA, Albers KM, Metz M, Paus R. Distinct roles for nerve growth factor and brain-derived neurotrophic factor in controlling the rate of hair follicle morphogenesis. J Invest Dermatol 2000; 114:314-20. [PMID: 10651992 DOI: 10.1046/j.1523-1747.2000.00864.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Increasing evidence suggests that neurotrophins play an important part in the control of the development of ectodermal derivatives, such as the hair follicle. Here, we show that, during hair follicle morphogenesis in C57BL/6 mice, nerve growth factor, brain-derived neurotrophic factor and their corresponding high-affinity tyrosine kinase receptors, TrkA and TrkB, show stringently controlled spatiotemporal expression patterns in the follicular epithelium and mesenchyme. Constitutive overexpression of nerve growth factor in mice is associated with a discrete, but significant acceleration of hair follicle morphogenesis, whereas this is not seen in brain-derived neurotrophic factor transgenic mice. In neonatal skin organ culture, nerve growth factor and brain-derived neurotrophic factor differentially influence hair follicle development: nerve growth factor accelerates late stages of hair follicle morphogenesis, whereas brain-derived neurotrophic factor does not show significant effects. This suggests that the morphogenetic properties of locally generated neurotrophins in the skin, similar to their classical neurotrophic functions, are quite distinct and depend on the response patterns of the corresponding neurotrophin target receptor-expressing cells in the developing hair follicle. These data further strengthen the concept that neurotrophin signaling is an important element in controlling the rate of hair follicle morphogenesis, yet also highlight the complexity of this signaling system.
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Affiliation(s)
- N V Botchkareva
- Department of Dermatology, Charité, Humboldt University, Berlin, Germany
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42
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Botchkareva NV, Botchkarev VA, Chen LH, Lindner G, Paus R. A role for p75 neurotrophin receptor in the control of hair follicle morphogenesis. Dev Biol 1999; 216:135-53. [PMID: 10588868 DOI: 10.1006/dbio.1999.9464] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
During hair follicle (HF) morphogenesis, p75 neurotrophin receptor (p75NTR) reportedly is the first growth factor receptor found to be expressed by those fibroblasts that later develop into the dermal papilla (DP) of the HF. However, the functional role of p75NTR in HF morphogenesis is still unknown. Studying HF development in fetal and neonatal C57BL/6 murine back skin, we show that p75NTR-immunoreactivity (IR) is prominently expressed by DP fibroblasts as well as by skin nerves during the early steps of HF development. In contrast, p75NTR-IR disappears from the DP in the fully developed HF and it is expressed only in the epithelial outer root sheath of the HF. Compared to age-matched wild-type animals, p75NTR knockout (-/-) mice show significant acceleration of HF morphogenesis, and DP fibroblasts of p75NTR knockout mice show reduced proliferative activity in situ, indicating alterations in their transition from proliferation to differentiation. Although no significant differences in the expression of adhesion molecules (NCAM), selected morphogens (TGFbeta-2, HGF/SF, FGF-2, KGF), or their receptors (TGFbetaR-II, m-met, FGFR-1) were seen between DP of p75NTR knockout and wild-type mice, p75NTR mutants showed a prominent upregulation of FGFR-2, a high-affinity receptor for KGF, in both follicular DP and epithelium. Furthermore, the administration of anti-KGF neutralizing antibody significantly inhibited acceleration of HF morphogenesis in p75NTR knockout mice in vivo. These observations suggest that p75NTR plays an important role during HF morphogenesis, functioning as a receptor that negatively controls HF development, most likely via alterations in DP fibroblast proliferation/differentiation and via downregulation of KGF/FGFR-2 signaling in the HF.
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Affiliation(s)
- N V Botchkareva
- Department of Dermatology, Charité, Humboldt University Berlin, Berlin, Germany
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43
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Kinkelin I, Stucky CL, Koltzenburg M. Postnatal loss of Merkel cells, but not of slowly adapting mechanoreceptors in mice lacking the neurotrophin receptor p75. Eur J Neurosci 1999; 11:3963-9. [PMID: 10583485 DOI: 10.1046/j.1460-9568.1999.00822.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Merkel cells are specialized epidermal cells which are abundantly found in touch-sensitive areas and which are innervated by slowly adapting mechanosensitive afferent fibres with large myelinated (Abeta) axons. The role of Merkel cells in mechanosensation, their developmental regulation and their influence on sensory neuron function are, however, incompletely understood. Here, we used mice lacking the neurotrophin receptor p75 which is expressed on Merkel cells to investigate their postnatal development and that of their innervating sensory neurons. Using morphological studies we now show that Merkel cells develop normally in both hairy and glabrous skin in these animals until 2 weeks old, but are progressively lost thereafter and have almost completely disappeared 2 months after birth. Using standard extracellular electrophysiological recording techniques we find that despite the profound loss of Merkel cells there is no corresponding reduction in the number of myelinated slowly adapting afferent fibres. Moreover, the mean mechanical threshold of these neurons and their average stimulus response function to suprathreshold mechanical stimuli does not change during the time period when more than 99% of Merkel cells are lost. We conclude that Merkel cells require p75 during the late postnatal development. However, neither the survival nor the mechanical sensitivity of slowly adapting mechanoreceptive Abeta-fibres depends on the presence of Merkel cells.
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Affiliation(s)
- I Kinkelin
- Department of Neurology, University of Würzburg, Josef-Schneider- Str. 11, D-97080 Würzburg, Germany
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44
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Paus R, Botchkarev VA, Botchkareva NV, Mecklenburg L, Luger T, Slominski A. The skin POMC system (SPS). Leads and lessons from the hair follicle. Ann N Y Acad Sci 1999; 885:350-63. [PMID: 10816666 DOI: 10.1111/j.1749-6632.1999.tb08690.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Human and murine skin are prominent extrapituitary sources and targets for POMC products. The expression of, for example, ACTH, alpha-MSH, beta-endorphin, and MC-1-receptors fluctuates during synchronized hair follicle cycling in C57BL/6 mice. Since hair growth can be induced by ACTH injections in mice and mink, and since high doses of MSH peptides modulate epidermal and/or follicle keratinocyte proliferation in murine skin organ culture, some POMC products may operate as locally generated growth modulators, in addition to their roles in cutaneous pigment and immunobiology. Intrafollicularly generated ACTH and alpha-MSH as well as their cognate receptors may assist in the maintenance of the peculiar immune privilege of the anagen hair bulb. Possibly, they are also involved in the development of the follicle pigmentary unit, with whose generation their expression coincides. Given that murine skin also expresses (in a hair-cycle-dependent way) CRH and CRH-R, which control pituitary POMC expression and in view of the fact that CRH arrests follicles in telogen, this suggests the existence of a local skin POMC system (SPS). This may be an integral component of cutaneous stress response-systems, and may most instructively be studied using the murine hair cycle as a model.
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Affiliation(s)
- R Paus
- Department of Dermatology, Charité, Humboldt-University, Berlin, Germany.
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45
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Paus R, Müller-Röver S, Van Der Veen C, Maurer M, Eichmüller S, Ling G, Hofmann U, Foitzik K, Mecklenburg L, Handjiski B. A comprehensive guide for the recognition and classification of distinct stages of hair follicle morphogenesis. J Invest Dermatol 1999; 113:523-32. [PMID: 10504436 DOI: 10.1046/j.1523-1747.1999.00740.x] [Citation(s) in RCA: 415] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Numerous spontaneous and experimentally induced mouse mutations develop a hair phenotype, which is often associated with more or less discrete abnormalities in hair follicle development. In order to recognize these, it is critically important to be able to determine and to classify accurately the major stages of normal murine hair follicle morphogenesis. As an aid, we propose a pragmatic and comprehensive guide, modified after previous suggestions by Hardy, and provide a list of easily recognizable classification criteria, illustrated by representative micrographs. Basic and more advanced criteria are distinguished, the former being applicable to all mouse strains and requiring only simple histologic stains (hematoxylin and eosin, Giemsa, periodic acid Schiff, alkaline phosphatase activity), the latter serving as auxiliary criteria, which require a pigmented mouse strain (like C57BL/6J) or immunohistochemistry (interleukin-1 receptor type I, transforming growth factor-beta receptor type II). In addition, we present simplified, computer-generated schematic drawings for the standardized recording and reporting of gene and antigen expression patterns during hair follicle development. This classification aid serves as a basic introduction into the field of hair follicle morphogenesis, aims at standardizing the presentation of related hair research data, and should become a useful tool when screening new mouse mutants for discrete abnormalities of hair follicle morphogenesis (compared with the respective wild type) in a highly reproducible, easily applicable, and quantifiable manner.
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Affiliation(s)
- R Paus
- Department of Dermatology, Charité, Humboldt University, Berlin, Germany.
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46
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Abstract
Several lines of evidence suggest that sensory nerves ending at the skin have profound influences on their target, the epidermis. To test the hypothesis, we examined the consequences of denervation on the paw skin of rats by eliminating its innervation. We investigated temporal changes of nerve degeneration, keratinocyte proliferation and differentiation, gene expression, and epidermal thickness. Nerve terminals in the epidermis began to degenerate within 24 h after denervation. All epidermal nerves were completely degenerated by 2 d. During the interval of nerve degeneration, there was a significant reduction of bromodeoxyuridine incorporation from 24 h of nerve injury (39 +/- 7% of the control side, p 0.01). By 2 d, there was a further reduction of bromodeoxyuridine labeling (11 +/- 8%, p < 0. 0001). The incorporation of bromodeoxyuridine remained depressed when the skin was denervated (35 +/- 11%, p < 0.01). Four days after eliminating skin innervation, the denervated epidermis became thinner than the control epidermis (70 +/- 8% of the control, p < 0. 01). Epidermal thinning was associated with a significant decrease in expression of glyceraldehyde-3-phosphate dehydrogenase and beta-actin transcripts (33 +/- 8% of the control epidermis from postoperative day 4, p < 0.001). Other aspects of keratinocyte differentiation, including the patterns of keratin expression, and programmed cell death, were unaltered by skin denervation. These data indicate that skin denervation is sufficient to influence keratinocyte proliferation and therefore epidermal thickness.
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Affiliation(s)
- S T Hsieh
- Department of Anatomy and Neurology, National Taiwan University, Taipei.
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47
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Botchkareva NV, Botchkarev VA, Metz M, Silos-Santiago I, Paus R. Retardation of hair follicle development by the deletion of TrkC, high-affinity neurotrophin-3 receptor. J Invest Dermatol 1999; 113:425-7. [PMID: 10469347 DOI: 10.1046/j.1523-1747.1999.00712.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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48
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Botchkarev VA, Botchkareva NV, Welker P, Metz M, Lewin GR, Subramaniam A, Bulfone-Paus S, Hagen E, Braun A, Lommatzsch M, Renz H, Paus AR. A new role for neurotrophins: involvement of brain-derived neurotrophic factor and neurotrophin-4 in hair cycle control. FASEB J 1999; 13:395-410. [PMID: 9973328 DOI: 10.1096/fasebj.13.2.395] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Neurotrophins exert many biological effects not directly targeted at neurons, including modulation of keratinocyte proliferation and apoptosis in vitro. Here we exploit the cyclic growth and regression activity of the murine hair follicle to explore potential nonneuronal functions of neurotrophins in the skin, and analyze the follicular expression and hair growth-modulatory function of BDNF, NT-4, and their high-affinity receptor, TrkB. The cutaneous expression of BDNF and NT-4 mRNA was strikingly hair cycle dependent and peaked during the spontaneous, apoptosis-driven hair follicle regression (catagen). During catagen, BDNF mRNA and immunoreactivity, as well as NT-4-immunoreactivity, were expressed in the regressing hair follicle compartments, whereas TrkB mRNA and immunoreactivity were seen in dermal papilla fibroblasts, epithelial strand, and hair germ. BDNF or NT-4 knockout mice showed significant catagen retardation, whereas BDNF-overexpressing mice displayed acceleration of catagen and significant shortening of hair length. Finally, BDNF and NT-4 accelerated catagen development in murine skin organ culture. Together, our data suggest that BDNF and NT-4 play a previously unrecognized role in skin physiology as agents of hair growth control. Thus, TrkB agonists and antagonists deserve exploration as novel hair growth-modulatory drugs for the management of common hair growth disorders.
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Affiliation(s)
- V A Botchkarev
- Department of Dermatology, Humboldt University, Berlin, D-13122 Germany
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Botchkarev VA, Welker P, Albers KM, Botchkareva NV, Metz M, Lewin GR, Bulfone-Paus S, Peters EM, Lindner G, Paus R. A new role for neurotrophin-3: involvement in the regulation of hair follicle regression (catagen). THE AMERICAN JOURNAL OF PATHOLOGY 1998; 153:785-99. [PMID: 9736028 PMCID: PMC1853006 DOI: 10.1016/s0002-9440(10)65621-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nervous system and hair follicle epithelium share a common ectodermal origin, and some neurotrophins (NTs) can modulate keratinocyte proliferation and apoptosis. Therefore, it is reasonable to ask whether NTs are also involved in hair growth control. Here, we show that the expression of NT-3 and its high-affinity receptor, tyrosine kinase C, in the skin of C57BL/6 mice is strikingly hair cycle-dependent, with maximal transcript and protein expression seen during spontaneous hair follicle regression (catagen). During catagen, NT-3 and tyrosine kinase C are co-expressed by terminal deoxynucleotidyl transferase-mediated in situ nick end labeling-positive keratinocytes in the club hair and secondary germ. NT-3-overexpressing transgenic mice show precocious catagen development during the postnatal initiation of hair follicle cycling, whereas heterozygous NT-3 knockout (+/-) mice display a significant catagen retardation. Finally, NT-3 stimulates catagen development in organ culture of normal C57BL/6 mouse skin. These observations suggest that the hair follicle is both a source and target of NT-3 and that NT-3/tyrosine kinase C signaling is functionally important in the control of hair follicle regression. Therefore, tyrosine kinase C agonists and antagonists deserve systematic exploration for the management of hair growth disorders that are related to premature (alopecia/effluvium) or retarded catagen (hirsutism/hypertrichosis).
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Affiliation(s)
- V A Botchkarev
- Department of Dermatology, Charité Hospital, Humboldt University, Berlin, Germany
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