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Paus R, Ramot Y, Kirsner RS, Tomic-Canic M. Topical L-thyroxine: The Cinderella among hormones waiting to dance on the floor of dermatological therapy? Exp Dermatol 2020; 29:910-923. [PMID: 32682336 PMCID: PMC7722149 DOI: 10.1111/exd.14156] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/28/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022]
Abstract
Topical hormone therapy with natural or synthetic ligands of nuclear hormone receptors such as glucocorticoids, vitamin D analogues and retinoids has a long and highly successful tradition in dermatology. Yet the dermatological potential of thyroid hormone receptor (TR) agonists has been widely ignored, despite abundant clinical, cell and molecular biology, mouse in vivo, and human skin and hair follicle organ culture data documenting a role of TR-mediated signalling in skin physiology and pathology. Here, we review this evidence, with emphasis on wound healing and hair growth, and specifically highlight the therapeutic potential of repurposing topical L-thyroxine (T4) for selected applications in future dermatological therapy. We underscore the known systemic safety and efficacy profile of T4 in clinical medicine, and the well-documented impact of thyroid hormones on, for example, human epidermal and hair follicle physiology, hair follicle epithelial stem cells and pigmentation, keratin expression, mitochondrial energy metabolism and wound healing. On this background, we argue that short-term topical T4 treatment deserves careful further preclinical and clinical exploration for repurposing as a low-cost, effective and widely available dermatotherapeutic, namely in the management of skin ulcers and telogen effluvium, and that its predictable adverse effects are well-manageable.
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Affiliation(s)
- Ralf Paus
- Dr. Phillip Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
- Centre for Dermatology Research, University of Manchester & NIHR Manchester Biomedical Research Centre, Manchester, UK
- Monasterium Laboratory, Münster, Germany
| | - Yuval Ramot
- Department of Dermatology, Hadassah Medical Center, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Robert S. Kirsner
- Dr. Phillip Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Marjana Tomic-Canic
- Dr. Phillip Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
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Malagola E, Chen R, Bombardo M, Saponara E, Dentice M, Salvatore D, Reding T, Myers S, Hills AP, Graf R, Sonda S. Local hyperthyroidism promotes pancreatic acinar cell proliferation during acute pancreatitis. J Pathol 2019; 248:217-229. [PMID: 30714146 DOI: 10.1002/path.5247] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/17/2018] [Accepted: 01/08/2019] [Indexed: 01/01/2023]
Abstract
Proliferation of pancreatic acinar cells is a critical process in the pathophysiology of pancreatic diseases, because limited or defective proliferation is associated with organ dysfunction and patient morbidity. In this context, elucidating the signalling pathways that trigger and sustain acinar proliferation is pivotal to develop therapeutic interventions promoting the regenerative process of the organ. In this study we used genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones to elucidate their role in acinar proliferation following caerulein-mediated acute pancreatitis in mice. In addition, molecular mechanisms mediating the effects of thyroid hormones were identified by genetic and pharmacological inactivation of selected signalling pathways.In this study we demonstrated that levels of the thyroid hormone 3,3',5-triiodo-l-thyronine (T3) transiently increased in the pancreas during acute pancreatitis. Moreover, by using genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones, we showed that T3 was required to promote proliferation of pancreatic acinar cells, without affecting the extent of tissue damage or inflammatory infiltration.Finally, upon genetic and pharmacological inactivation of selected signalling pathways, we demonstrated that T3 exerted its mitogenic effect on acinar cells via a tightly controlled action on different molecular effectors, including histone deacetylase, AKT, and TGFβ signalling.In conclusion, our data suggest that local availability of T3 in the pancreas is required to promote acinar cell proliferation and provide the rationale to exploit thyroid hormone signalling to enhance pancreatic regeneration. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Ermanno Malagola
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Rong Chen
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Marta Bombardo
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Enrica Saponara
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Monica Dentice
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Domenico Salvatore
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Theresia Reding
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Stephen Myers
- School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, Australia
| | - Andrew P Hills
- School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, Australia
| | - Rolf Graf
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland.,Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Sabrina Sonda
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland.,School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, Australia.,Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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Al-Shobaili HA, Ahmed AA, Rasheed Z. Recognition of oxidized albumin and thyroid antigens by psoriasis autoantibodies. A possible role of reactive-oxygen-species induced epitopes in chronic plaque psoriasis. Saudi Med J 2016; 36:1408-19. [PMID: 26620982 PMCID: PMC4707396 DOI: 10.15537/smj.2015.12.12612] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES To investigate the role of reactive-oxygen-species (ROS) induced epitopes on human-serum-albumin (HSA) and thyroid antigens in psoriasis autoimmunity. METHODS This study was performed in the College of Medicine, Qassim University, Buraidah, Saudi Arabia between May 2014 and February 2015. The study was designed to explore the role of ROS-induced epitopes in psoriasis autoimmunity. Singlet-oxygen (or ROS)-induced epitopes on protein (ROS-epitopes-albumin) was characterized by in-vitro and in-vivo. Thyroid antigens were prepared from rabbit thyroid, and thyroglobulin was isolated from thyroid extract. Immunocross-reactions of protein-A purified anti-ROS-epitopes-HSA-immunoglobulin G (IgGs) with thyroid antigen, thyroglobulin, and their oxidized forms were determined. Binding characteristics of autoantibodies in chronic plaque psoriasis patients (n=26) against ROS-epitopes-HSA and also with native and oxidized thyroid antigens were screened, and the results were compared with age-matched controls (n=22). RESULTS The anti-ROS-epitopes-HSA-IgGs showed cross-reactions with thyroid antigen, thyroglobulin and with their oxidized forms. High degree of specific binding by psoriasis IgGs to ROS-epitopes-HSA, ROS-thyroid antigen and ROS-thyroglobulin was observed. Immunoglobulin G from normal-human-controls showed negligible binding with all tested antigens. Moreover, sera from psoriasis patients had higher levels of carbonyl contents compared with control sera. CONCLUSION Structural alterations in albumin, thyroid antigens by ROS, generate unique neo-epitopes that might be one of the factors for the induction of autoantibodies in psoriasis.
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Affiliation(s)
- Hani A Al-Shobaili
- Department of Dermatology, College of Medicine, Qassim University, Buraidah, Kingdom of Saudi Arabia. E-mail.
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Yang F, Ma H, Belcher J, Butler MR, Redmond TM, Boye SL, Hauswirth WW, Ding XQ. Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration. FASEB J 2016; 30:4313-4325. [PMID: 27623928 DOI: 10.1096/fj.201600715r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/01/2016] [Indexed: 12/21/2022]
Abstract
Recent studies have implicated thyroid hormone (TH) signaling in cone photoreceptor viability. Using mouse models of retinal degeneration, we found that antithyroid treatment preserves cones. This work investigates the significance of targeting intracellular TH components locally in the retina. The cellular TH level is mainly regulated by deiodinase iodothyronine (DIO)-2 and -3. DIO2 converts thyroxine (T4) to triiodothyronine (T3), which binds to the TH receptor, whereas DIO3 degrades T3 and T4. We examined cone survival after overexpression of DIO3 and inhibition of DIO2 and demonstrated the benefits of these manipulations. Subretinal delivery of AAV5-IRBP/GNAT2-DIO3, which directs expression of human DIO3 specifically in cones, increased cone density by 30-40% in a Rpe65-/- mouse model of Lebers congenital amaurosis (LCA) and in a Cpfl1 mouse with Pde6c defect model of achromatopsia, compared with their respective untreated controls. Intravitreal and topical delivery of the DIO2 inhibitor iopanoic acid also significantly improved cone survival in the LCA model mice. Moreover, the expression levels of DIO2 and Slc16a2 were significantly higher in the diseased retinas, suggesting locally elevated TH signaling. We show that targeting DIOs protects cones, and intracellular inhibition of TH components locally in the retina may represent a novel strategy for retinal degeneration management.-Yang, F., Ma, H., Belcher, J., Butler, M. R., Redmond, T. M., Boye, S. L., Hauswirth, W. W., Ding, X.-Q. Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration.
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Affiliation(s)
- Fan Yang
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Hongwei Ma
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Joshua Belcher
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Michael R Butler
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, Bethesda, Maryland, USA
| | - Sanford L Boye
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA; and.,Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA; and.,Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA;
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Paul KB, Hedge JM, Rotroff DM, Hornung MW, Crofton KM, Simmons SO. Development of a Thyroperoxidase Inhibition Assay for High-Throughput Screening. Chem Res Toxicol 2014; 27:387-99. [DOI: 10.1021/tx400310w] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Katie B. Paul
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Joan M. Hedge
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Daniel M. Rotroff
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Michael W. Hornung
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Kevin M. Crofton
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Steven O. Simmons
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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Hypothalamic–Pituitary–Thyroid Axis Hormones Stimulate Mitochondrial Function and Biogenesis in Human Hair Follicles. J Invest Dermatol 2014; 134:33-42. [DOI: 10.1038/jid.2013.286] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/29/2013] [Accepted: 05/31/2013] [Indexed: 12/22/2022]
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Paul KB, Hedge JM, Macherla C, Filer DL, Burgess E, Simmons SO, Crofton KM, Hornung MW. Cross-species analysis of thyroperoxidase inhibition by xenobiotics demonstrates conservation of response between pig and rat. Toxicology 2013; 312:97-107. [DOI: 10.1016/j.tox.2013.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/02/2013] [Accepted: 08/09/2013] [Indexed: 10/26/2022]
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Paraguassú GM, da Guarda MG, Xavier FCA, Cangussu MCT, Rodriguez TT, Ramalho MJP, Pinheiro ALB, Ramalho LMP. Effects of LED phototherapy on relative wound contraction and reepithelialization during tissue repair in hypothyroid rats: morphometric and histological study. Lasers Med Sci 2013; 29:773-9. [PMID: 23975568 DOI: 10.1007/s10103-013-1419-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 08/07/2013] [Indexed: 01/17/2023]
Abstract
The aim of this study was to assess morphometrically and histologically, the effects of light-emitting diode (LED) (λ630 ± 20 nm) phototherapy on reepithelialization and wound contraction during tissue repair in hypothyroid rats. Thyroid hormone deficiency has been associated with disorders of tissue repair. LED phototherapy has been studied using several healing models, but their usefulness in the improvement of hypothyroidism wound healing remains unknown. Under general anesthesia, a standard surgical wound (1 cm(2)) was produced on the dorsum of 48 male Wistar rats divided into four groups of 12 animals each: EC-control euthyroid, ED-euthyroid + LED, HC-control hypothyroid, and HD-Hypothyroid + LED. The irradiation started immediately after surgery and was repeated every other day for 7 and 14 days. Photographs of the wound were taken at the day of the surgical procedure and on days 8 and 15 after surgery, when animals' deaths occurred. The specimens were removed, routinely processed, and stained with hematoxylin/eosin. Seven days after the surgery, it was possible to observe statistically significant reductions in the wound area of the irradiated euthyroid group, in comparison to hypothyroid group, irradiated and non-irradiated (ANOVA, p < 0.05). The reepithelialization was significantly higher in the euthyroid and hypothyroid groups irradiated with LED than in the non-irradiated groups (Fisher's test, p < 0.05). No significant difference was found in the experimental period of 14 days among the groups. The hypothyroidism delayed wound healing and the LED phototherapy, at these specific parameters, improved the process of reepithelialization in the presence of hypothyroidism.
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Affiliation(s)
- Gardênia Matos Paraguassú
- School of Dentistry, Federal University of Bahia, Avenida Araújo Pinho, 62. Canela, Salvador, BA, CEP 40140-110, Brazil
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Hypothyroidism improves random-pattern skin flap survival in rats. J Surg Res 2012; 178:524-8. [PMID: 22521221 DOI: 10.1016/j.jss.2012.03.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 03/06/2012] [Accepted: 03/26/2012] [Indexed: 11/20/2022]
Abstract
BACKGROUND The protective effect of hypothyroidism against ischemic or toxic conditions has been shown in various tissues. We investigated the effect of propylthiouracil (PTU)/methimazole (MMI)-induced hypothyroidism and acute local effect of MMI on the outcome of lethal ischemia in random-pattern skin flaps. MATERIALS AND METHODS Dorsal flaps with caudal pedicles were elevated at midline and flap survival was measured at the seventh day after surgery. The first group, as control, received 1 mL of 0.9% saline solution in the flap before flap elevation. In groups 2 and 3, hypothyroidism was induced by administration of either PTU 0.05% or MMI 0.04% in drinking water. The next four groups received local injections of MMI (10, 20, 50, or 100 μg/flap) before flap elevation. Local PTU injection was ignored due to insolubility of the agent. RESULTS Hypothyroidism was induced in chronic PTU- and MMI-treated groups, and animals in these groups showed significant increase in their flap survival, compared to control euthyroid rats (79.47% ± 10.49% and 75.48% ± 12.93% versus 52.26% ± 5.75%, respectively, P < 0.01). Acute local treatment of skin flaps with MMI failed to significantly affect the flap survival. CONCLUSION This study demonstrates for the first time that hypothyroidism improves survival of random-pattern skin flaps in rats.
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Huang MP, Rodgers KA, O'Mara R, Mehta M, Abuzahra HS, Tannenbaum AD, Persons K, Holick MF, Safer JD. The thyroid hormone degrading type 3 deiodinase is the primary deiodinase active in murine epidermis. Thyroid 2011; 21:1263-8. [PMID: 21936673 DOI: 10.1089/thy.2011.0105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Many tissues express thyroid hormone metabolizing deiodinases that both activate and inactivate thyroid hormones through conversion processes. Many believe that the primary role of thyroid hormone deiodinases is the activation of the prohormone thyroxine (T(4)) to the active hormone triiodothyronine because athyreotic humans can be treated with T(4) alone. In our hands a nonspecific deiodinase inhibitor (iopanoic acid [IOP]) decreased cutaneous cell proliferation in vitro, so we hypothesized that topical IOP would inhibit epidermal proliferation in vivo. METHODS IOP was applied topically to mice. Treatments were applied daily for 1 week. Skin biopsies were either stained for 5-bromo-2-deoxyuridine or flash-frozen to assay for deiodinase activity. RESULTS Topical IOP resulted in a dose-dependent increase in epidermal proliferation. Assay revealed significant inactivating type 3 deiodinase (Dio3) activity in the epidermis but little or no activating (Dio1 or Dio2) activity. Dio3 activity was decreased 44%±21% in epidermis from mice treated with low-dose IOP and 80%±4% in epidermis from mice treated with high-dose IOP (p<0.001). CONCLUSION We hypothesize that keratinocytes express Dio3 in vivo to maintain cutaneous health and prevent the skin from becoming hyperproliferative. Our data support the developing recognition that the primary role of thyroid hormone deiodinases in some tissues may be the degradation of thyroid hormone to protect the tissue against thyrotoxicosis.
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Affiliation(s)
- Max P Huang
- Section of Endocrinology, Diabetes, and Nutrition, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Bodó E, Kany B, Gáspár E, Knüver J, Kromminga A, Ramot Y, Bíró T, Tiede S, van Beek N, Poeggeler B, Meyer KC, Wenzel BE, Paus R. Thyroid-stimulating hormone, a novel, locally produced modulator of human epidermal functions, is regulated by thyrotropin-releasing hormone and thyroid hormones. Endocrinology 2010; 151:1633-42. [PMID: 20176727 DOI: 10.1210/en.2009-0306] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Several elements of the hypothalamic-pituitary-thyroid axis (HPT) reportedly are transcribed by human skin cell populations, and human hair follicles express functional receptors for TSH. Therefore, we asked whether the epidermis of normal human skin is yet another extrathyroidal target of TSH and whether epidermis even produces TSH. If so, we wanted to clarify whether intraepidermal TSH expression is regulated by TRH and/or thyroid hormones and whether TSH alters selected functions of normal human epidermis in situ. TSH and TSH receptor (TSH-R) expression were analyzed in the epidermis of normal human scalp skin by immunohistochemistry and PCR. In addition, full-thickness scalp skin was organ cultured and treated with TSH, TRH, or thyroid hormones, and the effect of TSH treatment on the expression of selected genes was measured by quantitative PCR and/or quantitative immunohistochemistry. Here we show that normal human epidermis expresses TSH at the mRNA and protein levels in situ and transcribes TSH-R. It also contains thyrostimulin transcripts. Intraepidermal TSH immunoreactivity is up-regulated by TRH and down-regulated by thyroid hormones. Although TSH-R immunoreactivity in situ could not be documented within the epidermis, but in the immediately adjacent dermis, TSH treatment of organ-cultured human skin strongly up-regulated epidermal expression of involucrin, loricrin, and keratins 5 and 14. Thus, normal human epidermis in situ is both an extrapituitary source and (possibly an indirect) target of TSH signaling, which regulates defined epidermal parameters. Intraepidermal TSH expression appears to be regulated by the classical endocrine controls that determine the systemic HPT axis.
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Affiliation(s)
- Eniko Bodó
- Department of Dermatology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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