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Olszewska AM, Nowak JI, Myszczynski K, Słominski A, Żmijewski MA. Dissection of an impact of VDR and RXRA on the genomic activity of 1,25(OH) 2D 3 in A431 squamous cell carcinoma. Mol Cell Endocrinol 2024; 582:112124. [PMID: 38123121 PMCID: PMC10872374 DOI: 10.1016/j.mce.2023.112124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/24/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Human skin is the natural source, place of metabolism, and target for vitamin D3. The classical active form of vitamin D3, 1,25(OH)2D3, expresses pluripotent properties and is intensively studied in cancer prevention and therapy. To define the specific role of vitamin D3 receptor (VDR) and its co-receptor retinoid X receptor alpha (RXRA) in genomic regulation, VDR or RXRA genes were silenced in the squamous cell carcinoma cell line A431 and treated with 1,25(OH)2D3 at long incubation time points 24 h/72 h. Extending the incubation time of A431 WT (wild-type) cells with 1,25(OH)2D3 resulted in a two-fold increase in DEGs (differentially expressed genes) and a change in the amount of downregulated from 37% to 53%. VDR knockout led to a complete loss of 1,25(OH)2D3-induced genome-wide gene regulation at 24 h time point, but after 72 h, 20 DEGs were found, of which 75% were downregulated, and most of them belonged to the gene ontology group "immune response". This may indicate the existence of an alternative, secondary response to 1,25(OH)2D3. In contrast, treatment of A431 ΔRXRA cells with 1,25(OH)2D3 for 24 h only partially affected DEGs, suggesting RXRA-independent regulation. Interestingly, overexpression of classic 1,25(OH)2D3 targets, like CYP24A1 (family 24 of subfamily A of cytochrome P450 member 1) or CAMP (cathelicidin antimicrobial peptide) was found to be RXRA-independent. Also, immunofluorescence staining of A431 WT cells revealed partial VDR/RXRA colocalization after 24 h and 72 h 1,25(OH)2D3 treatment. Comparison of transcriptome changes induced by 1,25(OH)2D3 in normal keratinocytes vs. cancer cells showed high cell type specific expression pattern with only a few genes commonly regulated by 1,25(OH)2D3. Activation of the genomic pathway at least partially reversed the expression of cancer-related genes, forming a basis for anti-cancer activates of 1,25(OH)2D3. In summary, VDR or RXRA independent genomic activities of 1,25(OH)2D3 suggest the involvement of alternative factors, opening new challenges in this field.
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Affiliation(s)
- Anna M Olszewska
- Department of Histology, Medical University of Gdansk, 1a Debinki, 80-211Gdansk, Poland
| | - Joanna I Nowak
- Department of Histology, Medical University of Gdansk, 1a Debinki, 80-211Gdansk, Poland
| | - Kamil Myszczynski
- Centre of Biostatistics and Bioinformatics Analysis Medical University of Gdansk, 1aDebinki, 80-211 Gdansk, Poland
| | - Andrzej Słominski
- Department of Dermatology, University of Alabama at Birmingham, AL 35292, USA; Birmingham Veteran Administration Medical Center, Birmingham, AL 35292, USA
| | - Michał A Żmijewski
- Department of Histology, Medical University of Gdansk, 1a Debinki, 80-211Gdansk, Poland.
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Leach K, Hannan FM, Josephs TM, Keller AN, Møller TC, Ward DT, Kallay E, Mason RS, Thakker RV, Riccardi D, Conigrave AD, Bräuner-Osborne H. International Union of Basic and Clinical Pharmacology. CVIII. Calcium-Sensing Receptor Nomenclature, Pharmacology, and Function. Pharmacol Rev 2020; 72:558-604. [PMID: 32467152 PMCID: PMC7116503 DOI: 10.1124/pr.119.018531] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor that responds to multiple endogenous agonists and allosteric modulators, including divalent and trivalent cations, L-amino acids, γ-glutamyl peptides, polyamines, polycationic peptides, and protons. The CaSR plays a critical role in extracellular calcium (Ca2+ o) homeostasis, as demonstrated by the many naturally occurring mutations in the CaSR or its signaling partners that cause Ca2+ o homeostasis disorders. However, CaSR tissue expression in mammals is broad and includes tissues unrelated to Ca2+ o homeostasis, in which it, for example, regulates the secretion of digestive hormones, airway constriction, cardiovascular effects, cellular differentiation, and proliferation. Thus, although the CaSR is targeted clinically by the positive allosteric modulators (PAMs) cinacalcet, evocalcet, and etelcalcetide in hyperparathyroidism, it is also a putative therapeutic target in diabetes, asthma, cardiovascular disease, and cancer. The CaSR is somewhat unique in possessing multiple ligand binding sites, including at least five putative sites for the "orthosteric" agonist Ca2+ o, an allosteric site for endogenous L-amino acids, two further allosteric sites for small molecules and the peptide PAM, etelcalcetide, and additional sites for other cations and anions. The CaSR is promiscuous in its G protein-coupling preferences, and signals via Gq/11, Gi/o, potentially G12/13, and even Gs in some cell types. Not surprisingly, the CaSR is subject to biased agonism, in which distinct ligands preferentially stimulate a subset of the CaSR's possible signaling responses, to the exclusion of others. The CaSR thus serves as a model receptor to study natural bias and allostery. SIGNIFICANCE STATEMENT: The calcium-sensing receptor (CaSR) is a complex G protein-coupled receptor that possesses multiple orthosteric and allosteric binding sites, is subject to biased signaling via several different G proteins, and has numerous (patho)physiological roles. Understanding the complexities of CaSR structure, function, and biology will aid future drug discovery efforts seeking to target this receptor for a diversity of diseases. This review summarizes what is known to date regarding key structural, pharmacological, and physiological features of the CaSR.
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Affiliation(s)
- Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Fadil M Hannan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Thor C Møller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Donald T Ward
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Enikö Kallay
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rebecca S Mason
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rajesh V Thakker
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Daniela Riccardi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Arthur D Conigrave
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Hans Bräuner-Osborne
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
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3
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Snoeck HW. Calcium regulation of stem cells. EMBO Rep 2020; 21:e50028. [PMID: 32419314 DOI: 10.15252/embr.202050028] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/14/2020] [Accepted: 04/03/2020] [Indexed: 12/14/2022] Open
Abstract
Pluripotent and post-natal, tissue-specific stem cells share functional features such as the capacity to differentiate into multiple lineages and to self-renew, and are endowed with specific cell maintenance mechanism as well as transcriptional and epigenetic signatures that determine stem cell identity and distinguish them from their progeny. Calcium is a highly versatile and ubiquitous second messenger that regulates a wide variety of cellular functions. Specific roles of calcium in stem cell niches and stem cell maintenance mechanisms are only beginning to be explored, however. In this review, I discuss stem cell-specific regulation and roles of calcium, focusing on its potential involvement in the intertwined metabolic and epigenetic regulation of stem cells.
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Affiliation(s)
- Hans-Willem Snoeck
- Columbia Center of Human Development, Columbia University Irving Medical Center, New York, NY, USA.,Division of Pulmonary Medicine, Allergy and Critical Care, Columbia University Irving Medical Center, New York, NY, USA.,Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.,Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
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Integrative cytological analysis of the effects of Ca 2+ and vitamin D 3 on extracellular Ca 2+ flux and intracellular Ca 2+ reserves in the mantle of the pearl oyster (Hyriopsis cumingii Lea). Comp Biochem Physiol B Biochem Mol Biol 2018; 227:50-55. [PMID: 30236454 DOI: 10.1016/j.cbpb.2018.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 09/06/2018] [Indexed: 11/22/2022]
Abstract
To examine Ca2+ absorption and transportation in the freshwater pearl oyster, Hyriopsis cumingii Lea, we studied the effects of different levels of either extracellular Ca2+ or 1,25(OH)2D3 on extracellular Ca2+ flux and intracellular Ca2+ concentrations in mantle cells using the non-invasive micro-test technique and laser scanning confocal microscopy. The inner and outer mantle (IM and OM) cells from mussels were cultured and then treated with different concentrations of Ca2+ and 1,25(OH)2D3. Extracellular Ca2+ flux and intracellular Ca2+ reserves were analyzed. The results showed that both extracellular Ca2+ and 1,25(OH)2D3 had significant effects on Ca2+ flux and reserves in mantle cells, especially in IM cells (P < .05). The increase in extracellular Ca2+ concentrations resulted in the conversion of extracellular Ca2+ flux into influx with an increase in flow rate (P < .05). The calcium ion fluorescence intensity of OM cells was higher than that of IM cells (P < .05). 1,25(OH)2D3 addition also significantly increased the influx rate of extracellular Ca2+, especially in IM cells, which were more sensitive to 1,25(OH)2D3 addition and had significantly higher Ca2+ influx rates than did OM cells (P < .05). Fluorescence intensities of intracellular Ca2+ first increased and then decreased with increasing 1,25(OH)2D3 levels. The study showed that IM cells play an important role in absorbing Ca2+ from the environment, while OM cells mainly function in the temporary storage and transportation of Ca2+ in the body. The current results suggested that high levels of extracellular Ca2+ (1.25 mM) or 1,25(OH)2D3 (over 100 IU/L) were favorable for Ca2+ uptake and maintenance in the body.
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Umar M, Sastry KS, Al Ali F, Al-Khulaifi M, Wang E, Chouchane AI. Vitamin D and the Pathophysiology of Inflammatory Skin Diseases. Skin Pharmacol Physiol 2018; 31:74-86. [DOI: 10.1159/000485132] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 11/07/2017] [Indexed: 12/13/2022]
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Abstract
Vitamin D, a secosteroid predominately obtained by endogenous production, has in recent years been linked to obesity and its comorbidities. The purpose of this review is to draw conclusions from animal and human studies on the effects of vitamin D on adipogenesis to identify the molecular links between vitamin D and obesity. The information presented herein was obtained from 4 databases (PubMed, CINAHL, Cochrane Library, Scopus) using predefined search terms, as well as research literature and other reviews. The effects of vitamin D on adipogenesis have been researched in several animal models, and the majority of these studies suggest vitamin D plays an inhibitory role in adipogenesis. Studies into vitamin D status and obesity in humans are limited, with the majority being observational epidemiological studies that provide no conclusions on cause and effect or clear links on the molecular mechanisms. The few cell culture and supplementation studies that have investigated adipogenesis in human cells indicate that, in contrast to findings from rodent studies, vitamin D is proadipogenic. There is insufficient evidence to determine whether 1) vitamin D deficiency is associated with a lean or obese phenotype, 2) vitamin D deficiency is a consequence of obesity, or (3) the effects of vitamin D on fat tissue are due to interactions with calcium.
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Affiliation(s)
- Clare F Dix
- Centre for Dietetic Research, School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia
| | | | - Olivia R L Wright
- Centre for Dietetic Research, School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia
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Silvagno F, Pescarmona G. Spotlight on vitamin D receptor, lipid metabolism and mitochondria: Some preliminary emerging issues. Mol Cell Endocrinol 2017; 450:24-31. [PMID: 28414049 DOI: 10.1016/j.mce.2017.04.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/07/2017] [Accepted: 04/09/2017] [Indexed: 12/19/2022]
Abstract
Transcriptional control and modulation of calcium fluxes underpin the differentiating properties of vitamin D (1,25(OH)2D3). In the latest years however few studies have pointed out the relevance of the mitochondrial effects of the hormone. It is now time to focus on the metabolic results of vitamin D receptor (VDR) action in mitochondria, which can explain the pleiotropic effects of 1,25(OH)2D3 and may elucidate few contrasting aspects of its activity. The perturbation of lipid metabolism described in VDR knockout mice and vitamin D deficient animals can be revisited based on the newly identified mechanism of action of 1,25(OH)2D3 in mitochondria. From the same point of view, the controversial role of 1,25(OH)2D3 in adipogenesis can be better interpreted.
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Affiliation(s)
- Francesca Silvagno
- Department of Oncology, University of Torino, Via Santena 5 bis, 10126 Torino, Italy.
| | - Gianpiero Pescarmona
- Department of Oncology, University of Torino, Via Santena 5 bis, 10126 Torino, Italy.
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Oda Y, Hu L, Nguyen T, Fong C, Tu CL, Bikle DD. Combined Deletion of the Vitamin D Receptor and Calcium-Sensing Receptor Delays Wound Re-epithelialization. Endocrinology 2017; 158:1929-1938. [PMID: 28368538 PMCID: PMC5460927 DOI: 10.1210/en.2017-00061] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/08/2017] [Indexed: 12/28/2022]
Abstract
When the skin is injured, keratinocytes proliferate, migrate, and differentiate to regenerate the epidermis. We recently showed that ablation of the vitamin D receptor (Vdr) in keratinocytes delays wound re-epithelialization in mice also fed a low-calcium diet, implicating a cooperative role of Vdr and calcium signaling in this process. In this study, we examined the role of vitamin D and calcium signaling in wound healing by deleting their receptors, Vdr and the calcium-sensing receptor (Casr). Gene expression profiling of neonatal epidermis lacking both Vdr and Casr [Vdr and Casr double knockout (DKO)] specifically in keratinocytes revealed that DKO affects a number of pathways relevant to wound healing, including Vdr, β-catenin, and adherens junction (AJ) signaling. In adult skin, DKO caused a significant delay in wound closure and re-epithelialization, whereas myofibroblast numbers and matrix deposition were unaffected. The injury-induced proliferation of epidermal keratinocytes was blunted in both epidermis and hair follicles, and expression of β-catenin target genes was reduced in the DKO. Expression of E-cadherin and desmoglein 1 was reduced in the shortened leading edges of the epithelial tongues re-epithelializing the wounds, consistent with the decreased migration rate of DKO keratinocytes in vitro. These results demonstrate that Vdr and Casr are required for β-catenin-regulated cell proliferation and AJ formation essential for re-epithelialization after wounding. We conclude that vitamin D and calcium signaling in keratinocytes are required for a normal regenerative response of the skin to wounding.
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Affiliation(s)
- Yuko Oda
- Department of Medicine, University of California San Francisco, San Francisco, California 94158
- Department of Dermatology, University of California San Francisco, San Francisco, California 94158
| | - Lizhi Hu
- Department of Medicine, University of California San Francisco, San Francisco, California 94158
- School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Thai Nguyen
- San Francisco Veterans Affairs Medical Center, San Francisco, California 94158
| | - Chak Fong
- San Francisco Veterans Affairs Medical Center, San Francisco, California 94158
| | - Chia-ling Tu
- San Francisco Veterans Affairs Medical Center, San Francisco, California 94158
| | - Daniel D. Bikle
- San Francisco Veterans Affairs Medical Center, San Francisco, California 94158
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Murata K, Takahashi A, Morita T, Nezu A, Fukumoto S, Saitoh M, Tanimura A. Effect of 1,25-dihydroxyvitamin D 3 on spontaneous calcium responses in rat dental epithelial SF2 cells revealed by long-term imaging. Biomed Res 2016; 37:329-334. [PMID: 28003579 DOI: 10.2220/biomedres.37.329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Genetically encoded calcium indicators (GECIs) are suitable for long-term imaging studies. In this study, we employed a highly sensitive GECI, G-GECO, and achieved efficient gene delivery with an adenoviral vector. The adenoviral vector allowed us to express G-GECO in more than 80% of cells. More than 80% of G-GECO-expressing cells showed an ATP-induced increase in fluorescence intensity due to Ca2+ release from intracellular stores and subsequent Ca2+ entry. The fluorescence intensity of these cells was increased more than 2-fold by stimulation with 10 μM ATP. We applied long-term imaging (for ~10 h) to monitor Ca2+ responses in SF2, a rat dental epithelial cell line, in culture conditions. SF2 cells showed intermittent rises in the intracellular Ca2+ concentration in the presence of 100 nM 1,25-dihydroxyvitamin D3. Many of these Ca2+ responses began at a specific location in the cytoplasm and spread throughout the entire cytoplasm. The combination of efficient gene delivery with an adenoviral vector and long-term imaging with a highly sensitive GECI enabled detection of intermittent Ca2+ responses that occur only 3-10 times/h/100 cells. This method could be useful to study the effects of Ca2+ responses for regulating longterm processes, such as gene expression, cell migration, and cell division, in many cell types.
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Affiliation(s)
- Kaori Murata
- Department of Pediatric Dentistry, School of Dentistry, Health Sciences University of Hokkaido
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Cubillos S, Norgauer J. Low vitamin D-modulated calcium-regulating proteins in psoriasis vulgaris plaques: S100A7 overexpression depends on joint involvement. Int J Mol Med 2016; 38:1083-92. [PMID: 27573000 PMCID: PMC5029959 DOI: 10.3892/ijmm.2016.2718] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/01/2016] [Indexed: 11/06/2022] Open
Abstract
Psoriasis is an inflammatory skin disease with or without joint involvement. In this disease, the thickened epidermis and impaired barrier are associated with altered calcium gradients. Calcium and vitamin D are known to play important roles in keratinocyte differentiation and bone metabolism. Intracellular calcium is regulated by calcium-sensing receptor (CASR), calcium release-activated calcium modulator (ORAI) and stromal interaction molecule (STIM). Other proteins modulated by vitamin D play important roles in calcium regulation e.g., calbindin 1 (CALB1) and transient receptor potential cation channel 6 (TRPV6). In this study, we aimed to investigate the expression of calcium-regulating proteins in the plaques of patients with psoriasis vulgaris with or without joint inflammation. We confirmed low calcium levels, keratinocyte hyperproliferation and an altered epidermal barrier. The CASR, ORAI1, ORAI3, STIM1, CALB1 and TRPV6 mRNA, as well as the sterol 27-hydroxylase (CYP27A1), 25-hydroxyvitamin D3 1-α-hydroxylase (CYP27B1) and 1,25-dihydroxyvitamin D3 24-hydroxylase (CYP24A1) protein levels were low in the plaques of patients with psoriasis. We demonstrated S100 calcium-binding protein A7 (S100A7) overexpression in the plaques of patients with psoriasis vulgaris with joint inflammation, compared with those without joint involvement. We suggest an altered capacity to regulate the intracellular Ca2+ concentration ([Ca2+]i), characterized by a reduced expression of CASR, ORAI1, ORAI3, STIM1, CALB1 and TRPV6 associated with diminished levels of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], which may be associated with an altered balance between keratinocyte proliferation and differentiation in the psoriatic epidermis. Additionally, differences in S100A7 expression depend on the presence of joint involvement.
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Affiliation(s)
- Susana Cubillos
- Department of Dermatology, Jena University Hospital, D-07743 Jena, Germany
| | - Johannes Norgauer
- Department of Dermatology, Jena University Hospital, D-07743 Jena, Germany
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11
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Bikle DD, Jiang Y, Nguyen T, Oda Y, Tu CL. Disruption of Vitamin D and Calcium Signaling in Keratinocytes Predisposes to Skin Cancer. Front Physiol 2016; 7:296. [PMID: 27462278 PMCID: PMC4940389 DOI: 10.3389/fphys.2016.00296] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/27/2016] [Indexed: 12/13/2022] Open
Abstract
1,25 dihydroxyvitamin D (1,25(OH)2D), the active metabolite of vitamin D, and calcium regulate epidermal differentiation. 1,25(OH)2D exerts its effects through the vitamin D receptor (VDR), a transcription factor in the nuclear hormone receptor family, whereas calcium acts through the calcium sensing receptor (Casr), a membrane bound member of the G protein coupled receptor family. We have developed mouse models in which the Vdr and Casr have been deleted in the epidermis (epidVdr−∕− and epidCasr−∕−). Both genotypes show abnormalities in calcium induced epidermal differentiation in vivo and in vitro, associated with altered hedgehog (HH) and β–catenin signaling that when abnormally expressed lead to basal cell carcinomas (BCC) and trichofolliculomas, respectively. The Vdr−∕− mice are susceptible to tumor formation following UVB or chemical carcinogen exposure. More recently we found that the keratinocytes from these mice over express long non-coding RNA (lncRNA) oncogenes such as H19 and under express lncRNA tumor suppressors such as lincRNA-21. Spontaneous tumors have not been observed in either the epidVdr−∕− or epidCasr−∕−. But in mice with epidermal specific deletion of both Vdr and Casr (epidVdr−∕−/epidCasr−∕− [DKO]) tumor formation occurs spontaneously when the DKO mice are placed on a low calcium diet. These results demonstrate important interactions between vitamin D and calcium signaling through their respective receptors that lead to cancer when these signals are disrupted. The roles of the β–catenin, hedgehog, and lncRNA pathways in predisposing the epidermis to tumor formation when vitamin D and calcium signaling are disrupted will be discussed.
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Affiliation(s)
- Daniel D Bikle
- Departments of Medicine and Dermatology, VA Medical Center and University of California, San Francisco San Francisco, CA, USA
| | - Yan Jiang
- Departments of Medicine and Dermatology, VA Medical Center and University of California, San Francisco San Francisco, CA, USA
| | - Thai Nguyen
- Departments of Medicine and Dermatology, VA Medical Center and University of California, San Francisco San Francisco, CA, USA
| | - Yuko Oda
- Departments of Medicine and Dermatology, VA Medical Center and University of California, San Francisco San Francisco, CA, USA
| | - Chia-Ling Tu
- Departments of Medicine and Dermatology, VA Medical Center and University of California, San Francisco San Francisco, CA, USA
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12
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Mostafa WZ, Hegazy RA. Vitamin D and the skin: Focus on a complex relationship: A review. J Adv Res 2015; 6:793-804. [PMID: 26644915 PMCID: PMC4642156 DOI: 10.1016/j.jare.2014.01.011] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 12/19/2022] Open
Abstract
The "sunshine" vitamin is a hot topic that attracted ample attention over the past decades, specially that a considerable proportion of the worldwide population are deficient in this essential nutrient. Vitamin D was primarily acknowledged for its importance in bone formation, however; increasing evidence point to its interference with the proper function of nearly every tissue in our bodies including brain, heart, muscles, immune system and skin. Thereby its deficiency has been incriminated in a long panel of diseases including cancers, autoimmune diseases, cardiovascular and neurological disorders. Its involvement in the pathogenesis of different dermatological diseases is no exception and has been the subject of much research over the recent years. In the current review, we will throw light on this highly disputed vitamin that is creating a significant concern from a dermatological perspective. Furthermore, the consequences of its deficiency on the skin will be in focus.
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Affiliation(s)
- Wedad Z. Mostafa
- Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt
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13
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Bikle DD, Oda Y, Tu CL, Jiang Y. Novel mechanisms for the vitamin D receptor (VDR) in the skin and in skin cancer. J Steroid Biochem Mol Biol 2015; 148:47-51. [PMID: 25445917 PMCID: PMC4361259 DOI: 10.1016/j.jsbmb.2014.10.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 07/25/2014] [Accepted: 10/28/2014] [Indexed: 11/17/2022]
Abstract
The VDR acting with or without its principal ligand 1,25(OH)2D regulates two central processes in the skin, interfollicular epidermal (IFE) differentiation and hair follicle cycling (HFC). Calcium is an important co-regulator with 1,25(OH)2D at least of epidermal differentiation. Knockout of the calcium sensing receptor (CaSR) in addition to VDR accelerates the development of skin cancer in mice on a low calcium diet. Coactivators such as mediator 1 (aka DRIP205) and steroid receptor coactivator 3 (SRC3) regulate VDR function at different stages of the differentiation process, with Med 1 essential for hair follicle differentiation and early stages of epidermal differentiation and proliferation and SRC3 essential for the latter stages of differentiation including formation of the permeability barrier and innate immunity. The corepressor of VDR, hairless (HR), is essential for hair follicle cycling, although its effect on epidermal differentiation in vivo is minimal. In its regulation of HFC and IFE VDR controls two pathways-wnt/β-catenin and sonic hedgehog (SHH). In the absence of VDR these pathways are overexpressed leading to tumor formation. Whereas, VDR binding to β-catenin may block its activation of TCF/LEF1 sites, β-catenin binding to VDR may enhance its activation of VDREs. 1,25(OH)2D promotes but may not be required for these interactions. Suppression of SHH expression by VDR, on the other hand, requires 1,25(OH)2D. The major point of emphasis is that the role of VDR in the skin involves a number of novel mechanisms, both 1,25(OH)2D dependent and independent, that when disrupted interfere with IFE differentiation and HFC, predisposing to cancer formation. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.
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Affiliation(s)
- Daniel D Bikle
- Department of Medicine and Dermatology, 1700 Owens Street, VA Medical Center and University of California, San Francisco, CA 94158, USA.
| | - Yuko Oda
- Department of Medicine and Dermatology, 1700 Owens Street, VA Medical Center and University of California, San Francisco, CA 94158, USA
| | - Chia-Ling Tu
- Department of Medicine and Dermatology, 1700 Owens Street, VA Medical Center and University of California, San Francisco, CA 94158, USA
| | - Yan Jiang
- Department of Medicine and Dermatology, 1700 Owens Street, VA Medical Center and University of California, San Francisco, CA 94158, USA
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14
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Abstract
Vitamin D and calcium are well-established regulators of keratinocyte proliferation and differentiation. Therefore, it was not a great surprise that deletion of the vitamin D receptor (VDR) should predispose the skin to tumor formation, and that the combination of deleting both the VDR and calcium sensing receptor (CaSR) should be especially pro-oncogenic. In this review I have examined 4 mechanisms that appear to underlie the means by which VDR acts as a tumor suppressor in skin. First, DNA damage repair is curtailed in the absence of the VDR, allowing mutations in DNA to accumulate. Second and third involve the increased activation of the hedgehog and β-catenin pathways in the epidermis in the absence of the VDR, leading to poorly regulated proliferation with reduced differentiation. Finally, VDR deletion leads to a shift in the expression of long noncoding RNAs toward a more oncogenic profile. How these different mechanisms interact and their relative importance in the predisposition of the VDR null epidermis to tumor formation remain under active investigation.
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Affiliation(s)
- Daniel D Bikle
- VA Medical Center and University of California San Francisco, 1700 Owens Street, Room 373, San Francisco, CA 94158, USA
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15
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Voisset C, García-Rodríguez N, Birkmire A, Blondel M, Wellinger RE. Using yeast to model calcium-related diseases: example of the Hailey-Hailey disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2315-21. [PMID: 24583118 DOI: 10.1016/j.bbamcr.2014.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/25/2014] [Accepted: 02/16/2014] [Indexed: 02/05/2023]
Abstract
Cross-complementation studies offer the possibility to overcome limitations imposed by the inherent complexity of multicellular organisms in the study of human diseases, by taking advantage of simpler model organisms like the budding yeast Saccharomyces cerevisiae. This review deals with, (1) the use of S. cerevisiae as a model organism to study human diseases, (2) yeast-based screening systems for the detection of disease modifiers, (3) Hailey-Hailey as an example of a calcium-related disease, and (4) the presentation of a yeast-based model to search for chemical modifiers of Hailey-Hailey disease. The preliminary experimental data presented and discussed here show that it is possible to use yeast as a model system for Hailey-Hailey disease and suggest that in all likelihood, yeast has the potential to reveal candidate drugs for the treatment of this disorder. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Cécile Voisset
- Institut National de la Santé et de la Recherche Médicale UMR 1078; Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France
| | - Néstor García-Rodríguez
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), University of Seville, Avd. Americo Vespucio SN, 41092 Sevilla, Spain
| | - April Birkmire
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), University of Seville, Avd. Americo Vespucio SN, 41092 Sevilla, Spain
| | - Marc Blondel
- Institut National de la Santé et de la Recherche Médicale UMR 1078; Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France.
| | - Ralf Erik Wellinger
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), University of Seville, Avd. Americo Vespucio SN, 41092 Sevilla, Spain
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16
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Tu CL, Bikle DD. Role of the calcium-sensing receptor in calcium regulation of epidermal differentiation and function. Best Pract Res Clin Endocrinol Metab 2013; 27:415-27. [PMID: 23856269 PMCID: PMC3713412 DOI: 10.1016/j.beem.2013.03.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The epidermis is a stratified squamous epithelium composed of proliferating basal and differentiated suprabasal keratinocytes. It serves as the body's major physical and chemical barrier against infection and harsh environmental insults, as well as preventing excess water loss from the body into the atmosphere. Calcium is a key regulator of the proliferation and differentiation in keratinocytes. Elevated extracellular Ca(2+) concentration ([Ca(2+)]o) raises the levels of intracellular free calcium ([Ca(2+)]i), promotes cell-cell adhesion, and activates differentiation-related genes. Keratinocytes deficient in the calcium-sensing receptor fail to respond to [Ca(2+)]o stimulation and to differentiate, indicating a role for the calcium-sensing receptor in transducing the [Ca(2+)]o signal during differentiation. The concepts derived from in vitro gene knockdown experiments have been evaluated and confirmed in three mouse models in vivo.
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Affiliation(s)
- Chia-Ling Tu
- Endocrine Unit, Veterans Affair Medical Center and The University of California, San Francisco, CA, USA
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17
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Tu CL, Crumrine DA, Man MQ, Chang W, Elalieh H, You M, Elias PM, Bikle DD. Ablation of the calcium-sensing receptor in keratinocytes impairs epidermal differentiation and barrier function. J Invest Dermatol 2012; 132:2350-2359. [PMID: 22622426 PMCID: PMC3434298 DOI: 10.1038/jid.2012.159] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The calcium-sensing receptor (CaR) plays an essential role in mediating Ca2+-induced keratinocyte differentiation in vitro. In this study, we generated keratinocyte-specific CaR knockout (EpidCaR-/-) mice to investigate the function of the CaR in epidermal development in vivo. EpidCaR-/- mice exhibited a delay in permeability barrier formation during embryonic development. Ion capture cytochemistry detected the loss of the epidermal Ca2+ gradient in the EpidCaR-/- mice. The expression of terminal differentiation markers and key enzymes mediating epidermal sphingolipid transport and processing in the EpidCaR-/- epidermis was significantly reduced. The EpidCaR-/- epidermis displayed a marked decrease in the number of lamellar bodies and lamellar body secretion, thinner lipid-bound cornified envelopes and a defective permeability barrier. Consistent with in vivo results, epidermal keratinocytes cultured from EpidCaR-/- mice demonstrated abnormal Ca2+I handling and diminished differentiation. The impairment in epidermal differentiation and permeability barrier in EpidCaR-/- mice maintained on a low calcium (0.02%) diet is more profound and persistent with age then in EpidCaR-/- mice maintained on a normal calcium (1.3%) diet. Deleting CaR perturbs the epidermal Ca2+ gradient and impairs keratinocyte differentiation and permeability barrier homeostasis, indicating a key role for the CaR in normal epidermal development.
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Affiliation(s)
- Chia-Ling Tu
- Endocrine Unit, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA.
| | - Debra A Crumrine
- Dermatology Service, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA
| | - Mao-Qiang Man
- Dermatology Service, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA
| | - Wenhan Chang
- Endocrine Unit, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA
| | - Hashem Elalieh
- Endocrine Unit, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA
| | - Michael You
- Endocrine Unit, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA
| | - Peter M Elias
- Dermatology Service, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA
| | - Daniel D Bikle
- Endocrine Unit, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California, USA
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18
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Abstract
The keratinocytes of the skin are unique in being not only the primary source of vitamin D for the body, but in possessing both the enzymatic machinery to metabolize the vitamin D produced to active metabolites (in particular 1,25(OH)(2)D) and the vitamin D receptor (VDR) that enables the keratinocytes to respond to the 1,25(OH)(2)D thus generated. Numerous functions of the skin are regulated by vitamin D and/or its receptor. These include inhibition of proliferation, stimulation of differentiation including formation of the permeability barrier, promotion of innate immunity, regulation of the hair follicle cycle, and suppression of tumor formation. Regulation of these actions is exerted by a number of different coregulator complexes including the coactivators vitamin D receptor interacting protein (DRIP) complex also known as Mediator and the steroid receptor coactivator (SRC) family (of which SRC 2 and 3 are found in keratincytes), the inhibitor hairless (Hr), and β-catenin whose impact on VDR function is complex. Different coregulators appear to be involved in different VDR regulated functions. This review will examine the various functions of vitamin D and its receptor in the skin, and explore the mechanisms by which these functions are regulated.
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Affiliation(s)
- Daniel D Bikle
- Veterans Affairs Medical Center/University of California, San Francisco, San Francisco, CA 94121, USA.
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19
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Abstract
The keratinocytes of the skin are unique in being not only the primary source of vitamin D for the body, but in possessing the enzymatic machinery to metabolize vitamin D to its active metabolite 1,25(OH)(2)D. Furthermore, these cells also express the vitamin D receptor (VDR) that enables them to respond to the 1,25(OH)(2)D they produce. Numerous functions of the skin are regulated by 1,25(OH)(2)D and/or its receptor. These include inhibition of proliferation, stimulation of differentiation including formation of the permeability barrier, promotion of innate immunity, and promotion of the hair follicle cycle. Regulation of these actions is exerted by a number of different coregulators including the coactivators DRIP and SRC, the cosuppressor hairless (Hr), and β-catenin. This review will examine the regulation of vitamin D production and metabolism in the skin, and explore the various functions regulated by 1,25(OH)(2)D and its receptor.
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Affiliation(s)
- Daniel D Bikle
- Veterans Affairs Medical Center, University of California San Francisco, San Francisco, CA 94121, USA.
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20
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Abstract
Vitamin D has been produced by plants and animals almost from the time life began. The ability to transport and metabolize vitamin D to more active forms evolved as the structures of plants and animals became more complex, and the cells within these organisms took on more specialized functions. In higher-order animals, the vitamin D receptor (VDR) is found in nearly every cell, and the ability of the cell to produce the active hormone, 1,25(OH)2D, is also widely distributed. Furthermore, the physiological functions with which vitamin D signalling is now associated are as diverse as the tissues in which the VDR is located. Why is this, and is there a common theme? This viewpoint article argues that there is. All cells maintain a fairly constant and submicromolar concentration of free calcium. Calcium is an important regulator of many processes within the cell. The ebb and flow of calcium within cells is controlled by calcium pumps, antiporters and channels. Animals with calcified exo- or endoskeletons have an additional need for calcium, a need that changes during the life cycle of the organism. In this article, I make the case that vitamin D signalling evolved to enable the organism to effectively regulate calcium flux, storage and signalling and that such regulation is critical for the evolutionary process.
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Affiliation(s)
- Daniel D Bikle
- San Francisco Veterans Affairs Medical Center, University of California at San Francisco, CA, USA.
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21
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Abstract
The incidence of nonmelanoma skin cancer is increasing every year. Basal cell carcinoma and squamous cell carcinoma are the two major types of nonmelanoma skin cancer. Among other factors, understanding the potential role of nutrients in the development, progression, and treatment of nonmelanoma skin cancer is critical. This contribution provides a review of the nutrients that have been more extensively investigated in the literature with regard to nonmelanoma skin cancer, including dietary fats, retinol, carotenoids, vitamin C, vitamin D, vitamin E, selenium, copper, iron, zinc, green tea, and black tea.
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Affiliation(s)
- Michael J Payette
- Department of Dermatology, MC-6230, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
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22
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The transcriptional coactivator DRIP/mediator complex is involved in vitamin D receptor function and regulates keratinocyte proliferation and differentiation. J Invest Dermatol 2010; 130:2377-88. [PMID: 20520624 DOI: 10.1038/jid.2010.148] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mediator is a multisubunit coactivator complex that facilitates transcription of nuclear receptors. We investigated the role of the mediator complex as a coactivator for vitamin D receptor (VDR) in keratinocytes. Using VDR affinity beads, the vitamin D receptor interacting protein (DRIP)/mediator complex was purified from primary keratinocytes, and its subunit composition was determined by mass spectrometry. The complex included core subunits, such as DRIP205/MED1 (MED1), that directly binds to VDR. Additional subunits were identified that are components of the RNA polymerase II complex. The functions of different mediator components were investigated by silencing its subunits. The core subunit MED1 facilitates VDR activity and regulating keratinocyte proliferation and differentiation. A newly described subunit MED21 also has a role in promoting keratinocyte proliferation and differentiation, whereas MED10 has an inhibitory role. Blocking MED1/MED21 expression caused hyperproliferation of keratinocytes, accompanied by increases in mRNA expression of the cell cycle regulator cyclin D1 and/or glioma-associated oncogene homolog. Blocking MED1 or MED21 expression also resulted in defects in calcium-induced keratinocyte differentiation, as indicated by decreased expression of differentiation markers and decreased translocation of E-cadherin to the membrane. These results show that keratinocytes use the transcriptional coactivator mediator to regulate VDR functions and control keratinocyte proliferation and differentiation.
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23
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Bouillon R, Verstuyf A, Mathieu C, Van Cromphaut S, Masuyama R, Dehaes P, Carmeliet G. Vitamin D resistance. Best Pract Res Clin Endocrinol Metab 2006; 20:627-45. [PMID: 17161336 DOI: 10.1016/j.beem.2006.09.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Vitamin D is a secosteroid of nutritional origin but can also be generated in the skin by ultraviolet light. After two hydroxylations 1,25-(OH)2 vitamin D avidly binds and activates the vitamin D receptor (VDR), a nuclear transcription factor, hereby regulating a large number of genes. The generation of VDR deficient mice has expanded the knowledge on vitamin D from a calcium-regulating hormone to a humoral factor with extensive actions. The effects of the vitamin D system on calcium and bone homeostasis are largely mediated by promoting active intestinal calcium transport via the induction of the epithelial calcium channel TRPV6. Although VDR is redundant in bone, it may regulate the differentiation and function of several bone cells. In skin, VDR expression in keratinocytes is essential in a ligand-independent manner for the maintenance of the normal hair cycle. Therefore, VDR but not vitamin D deficiency results in alopecia. Moreover, 1,25-(OH)2 vitamin D impairs the proliferation not only of keratinocytes but also of many cell types by regulating the expression of cell cycle genes, leading to a G1 cell cycle arrest. In addition, VDR inactivation in mice results in high renin hypertension, cardiac hypertrophy and thrombogenesis. Finally, a dual effect of vitamin D was observed in the immune system where it stimulates the innate immune system while tapering down excessive activation of the acquired immune system. Taken together, the vitamin D endocrine system not only regulates calcium homeostasis but affects several systems mainly by altering gene expression but also by ligand-independent actions.
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Affiliation(s)
- Roger Bouillon
- Laboratory for Experimental Medicine and Endocrinology, Campus Gasthuisberg, Onderwijs & Navorsing 1, Herestraat 49, bus 902, B-3000 Leuven, Belgium.
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Abstract
1alpha,25-Dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)], the active metabolite of vitamin D(3), is known for the maintenance of mineral homeostasis and normal skeletal architecture. However, apart from these traditional calcium-related actions, 1,25-(OH)(2)D(3) and its synthetic analogs are being increasingly recognized for their potent antiproliferative, prodifferentiative, and immunomodulatory activities. These actions of 1,25-(OH)(2)D(3) are mediated through vitamin D receptor (VDR), which belongs to the superfamily of steroid/thyroid hormone nuclear receptors. Physiological and pharmacological actions of 1,25-(OH)(2)D(3) in various systems, along with the detection of VDR in target cells, have indicated potential therapeutic applications of VDR ligands in inflammation (rheumatoid arthritis, psoriatic arthritis), dermatological indications (psoriasis, actinic keratosis, seborrheic dermatitis, photoaging), osteoporosis (postmenopausal and steroid-induced osteoporosis), cancers (prostate, colon, breast, myelodysplasia, leukemia, head and neck squamous cell carcinoma, and basal cell carcinoma), secondary hyperparathyroidism, and autoimmune diseases (systemic lupus erythematosus, type I diabetes, multiple sclerosis, and organ transplantation). As a result, VDR ligands have been developed for the treatment of psoriasis, osteoporosis, and secondary hyperparathyroidism. Furthermore, encouraging results have been obtained with VDR ligands in clinical trials of prostate cancer and hepatocellular carcinoma. This review deals with the molecular aspects of noncalcemic actions of vitamin D analogs that account for the efficacy of VDR ligands in the above-mentioned indications.
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Affiliation(s)
- Sunil Nagpal
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
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25
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Bikle DD, Chang S, Crumrine D, Elalieh H, Man MQ, Choi EH, Dardenne O, Xie Z, Arnaud RS, Feingold K, Elias PM. 25 Hydroxyvitamin D 1 alpha-hydroxylase is required for optimal epidermal differentiation and permeability barrier homeostasis. J Invest Dermatol 2004; 122:984-92. [PMID: 15102089 DOI: 10.1111/j.0022-202x.2004.22424.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Keratinocytes express high levels of 25OHD 1alpha-hydroxylase (1OHase). The product of this enzyme, 1,25-dihydroxyvitamin D (1,25(OH)(2)D), promotes the differentiation of keratinocytes in vitro suggesting an important role for this enzyme in epidermal differentiation. To test whether 1OHase activity is essential for keratinocyte differentiation in vivo we examined the differentiation process in mice null for the expression of the 1alphaOHase gene (1alphaOHase(-/-)). Heterozygotes for the null allele were bred, and the progeny genotyped by PCR. The epidermis of the 1alphaOHase(-/-) animals and their wild-type littermates (1alphaOHase(+/+)) were examined by histology at the light and electron microscopic level, by immunocytochemistry for markers of differentiation, and by function examining the permeability barrier using transepidermal water loss (TEWL). No gross epidermal phenotype was observed; however, immunocytochemical assessment of the epidermis revealed a reduction in involucrin, filaggrin, and loricrin-markers of differentiation in the keratinocyte and critical for the formation of the cornified envelope. These observations were confirmed at the electron microscopic level, which showed a reduction in the F (containing filaggrin) and L (containing loricrin) granules and a reduced calcium gradient. The functional significance of these observations was tested using TEWL to evaluate the permeability barrier function of the epidermis. Although TEWL was normal in the basal state, following disruption of the barrier using tape stripping, the 1alphaOHase(-/-) animals displayed a markedly delayed recovery of normal barrier function. This delay was associated with a reduction in lamellar body secretion and a failure to reform the epidermal calcium gradient. Thus, the 25OHD 1OHase is essential for normal epidermal differentiation, most likely by producing the vitamin D metabolite, 1,25(OH)(2)D, responsible for inducing the proteins regulating calcium levels in the epidermis that are critical for the generation and maintenance of the barrier.
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Affiliation(s)
- D D Bikle
- Department of Medicine, Veterans Affairs Medical Center and University of California, San Francisco 94121, USA.
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Abstract
Both calcium and 1,25(OH)(2)D promote the differentiation of keratinocytes in vitro. The autocrine or paracrine production of 1,25(OH)(2)D by keratinocytes combined with the critical role of the epidermal calcium gradient in regulating keratinocyte differentiation in vivo suggest the physiologic importance of this interaction. The interactions occur at a number of levels. Calcium and 1,25(OH)(2)D synergistically induce involucrin, a protein critical for cornified envelope formation. The involucrin promoter contains an AP-1 site essential for calcium and 1,25(OH)(2)D induction and an adjacent VDRE essential for 1,25(OH)(2)D but not calcium induction. Calcium regulates coactivator complexes that bind to the Vitamin D receptor (VDR). Nuclear extracts from cells grown in low calcium contain an abundance of DRIP(205), whereas calcium induced differentiation leads to reduced DRIP(205) and increased SRC 3 which replaces DRIP in its binding to the VDR. In vivo models support the importance of 1,25(OH)(2)D-calcium interactions in epidermal differentiation. The epidermis of 1alphaOHase null mice fails to form a normal calcium gradient, has reduced expression of proteins critical for barrier function, and shows little recovery of the permeability barrier when disrupted. Thus in vivo and in vitro, calcium and 1,25(OH)(2)D interact at multiple levels to regulate epidermal differentiation.
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Affiliation(s)
- D D Bikle
- Department of Medicine, Veterans Affairs Medical Center, University of California, San Francisco, CA 94121, USA.
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Bikle DD, Xie Z, Ng D, Tu CL, Oda Y. Squamous cell carcinomas fail to respond to the prodifferentiating actions of 1,25(OH)2D: why? Recent Results Cancer Res 2003; 164:111-22. [PMID: 12899516 DOI: 10.1007/978-3-642-55580-0_7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1,25(OH)2D regulates a number of cellular events which contribute to its ability to stimulate differentiation of the keratinocyte. 1,25(OH)2D raises the intracellular calcium (Cai) level in part by increasing the expression of the calcium receptor (CaR). This sensitizes the cell to extracellular calcium, triggering the signaling pathway coupled to the CaR, which results in a rise in Cai. 1,25(OH)2D induces the family of phospholipases C (PLC). These enzymes mediate the hydrolysis of phosphatidyl inositol bisphosphate (PIP2) to form inositol tris phosphate (IP3) and diacylglycerol (DG), which stimulate calcium release from intracellular stores and activate protein kinases C (PKC), respectively. The CaR and other G protein coupled receptors signal through PLC-beta, whereas tyrosine kinase growth factor receptors such as the EGF receptor signal through PLC-gamma. Calcium and PKC regulate the expression of genes in part by controlling the levels and activity of AP-1 transcription factors. 1,25(OH)2D also directly induces structural genes such as involucrin, a substrate for transglutaminase, which crosslinks it to other substrates to form the cornified envelope. 1,25(OH)2D regulates gene expression by activating the vitamin D receptor (VDR), a transcription factor, which, in combination with the retinoid X receptor (RXR) or retinoid A receptor (RAR), binds to its vitamin D response elements (VDRE) in the promoters of genes whose expression it regulates. The VDR also binds to one of two coactivator complexes, Mediator/DRIP (VDR interacting proteins) or p160/SRC (steroid hormone receptor complex), complexes which link the VDR to the RNA polymerase complex. We have recently discovered that the binding of VDR to these complexes is sequential. Binding to Mediator/DRIP occurs in the undifferentiated keratinocyte, but as the cell differentiates, DRIP(205) (the key protein of the DRIP complex binding to the VDR) levels fall, and p160/SRC binding takes over. We hypothesize that this sequential replacement of Mediator/DRIP by p160/SRC is critical for differentiation. Squamous cell carcinomas (SCC) fail to respond to the prodifferentiating actions of 1,25(OH)2D. These cells have normal levels of VDR and normal binding of VDR to VDREs. However, they fail to down-regulate DRIP(205) such that the p160/SRC complex fails to bind to VDR. This lack of sequential binding of these coactivator complexes to the VDR, we believe, maintains the cell in a state of continued proliferation and blocks the ability of 1,25(OH)2D to induce the expression of genes required for the differentiation process.
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Affiliation(s)
- Daniel D Bikle
- Veterans Affairs Medical Center (111 N), University of California, 4150 Clement Street, San Francisco, CA 94121, USA.
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28
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Bikle DD, Tu CL, Xie Z, Oda Y. Vitamin D regulated keratinocyte differentiation: role of coactivators. J Cell Biochem 2003; 88:290-5. [PMID: 12520529 DOI: 10.1002/jcb.10339] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
1,25 Dihydroxyvitamin D (1,25(OH)(2)D) regulates the differentiation of keratinocytes. 1,25(OH)(2)D raises intracellular free calcium (Cai) as a necessary early step toward stimulating differentiation. 1,25(OH)(2)D induces the calcium sensing receptor (CaR) in keratinocytes and enhances the calcium response of these cells. Activation of the CaR by calcium increases intracellular free calcium by a mechanism involving phospholipase C (PLC) cleavage of phosphatidylinositolbisphosphate into inositoltrisphosphate (IP(3)) and diacylglycerol (DG). 1,25(OH)(2)D induces the family of PLCs. PLC-gamma1 has a DR6 VDRE in its promoter which binds and is activated by VDR/RAR rather than VDR/RXR. The involucrin gene, which encodes a critical component of the cornified envelope, contains a DR3 VDRE in its promoter that acts in conjunction with a nearby AP-1 site. The sequential regulation of these genes is critical for the differentiation process. In undifferentiated keratinocytes, the VDR binds preferentially to the DRIP complex of coactivators. However, with differentiation DRIP 205 is no longer produced, and the VDR switches partners to the SRC family (SRC2 and 3). These studies suggest that at least part of the sequential activation of genes required during keratinocyte differentiation is regulated by the change (availability) of these different coactivator complexes.
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Affiliation(s)
- D D Bikle
- Department of Medicine, Veterans Affairs Medical Center and University of California, San Francisco, CA 94121, USA.
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Bikle DD, Ng D, Oda Y, Hanley K, Feingold K, Xie Z. The vitamin D response element of the involucrin gene mediates its regulation by 1,25-dihydroxyvitamin D3. J Invest Dermatol 2002; 119:1109-13. [PMID: 12445200 DOI: 10.1046/j.1523-1747.2002.19508.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Involucrin is a major protein of the cornified envelope of keratinocytes that provides much of the structural integrity of skin. Its expression is stimulated by a number of agents including calcium and 1,25-dihydroxy-vitamin D3 that promote the differentiation process in keratinocytes. Within the distal regulatory region of the involucrin promoter lies an AP-1 site and an element homologous to other vitamin D response elements. In previous studies mutation of the AP-1 site was found to reduce basal activity and block calcium stimulation of the involucrin promoter, whereas the vitamin D response element was not critical for calcium regulation. In this study both elements proved to be important for 1,25-dihydroxyvitamin D3 stimulation of the involucrin promoter. Mutation of the AP-1 site reduced basal activity and blocked 1,25-dihydroxyvitamin D3 stimulation of the involucrin promoter. In contrast, mutation of the vitamin D response element did not reduce basal expression of the involucrin promoter or prevent calcium stimulation of involucrin gene expression, but blocked 1,25-dihydroxyvitamin D3 stimulation. The vitamin D response element from the involucrin gene bound the vitamin D receptor and the retinoid X receptor, but not the retinoic acid receptor, in a specific manner. We conclude that the AP-1 site and the vitamin D response element in the involucrin promoter play important roles in mediating the action of 1,25-dihydroxyvitamin D3 on involucrin expression, but the vitamin D response element provides specificity for the 1,25-dihydroxyvitamin D3 response lacking at the AP-1 site.
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Affiliation(s)
- Daniel D Bikle
- Department of Medicine, Veterans Affairs Medical Center and University of California, San Francisco, USA.
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Komuves L, Oda Y, Tu CL, Chang WH, Ho-Pao CL, Mauro T, Bikle DD. Epidermal expression of the full-length extracellular calcium-sensing receptor is required for normal keratinocyte differentiation. J Cell Physiol 2002; 192:45-54. [PMID: 12115735 DOI: 10.1002/jcp.10107] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The importance of the extracellular calcium-sensing receptor (CaR) in the stringent control of extracellular Ca(2+) concentration is well established. However, the presence of CaR in tissues not directly involved in regulating mineral ion homeostasis such as the epidermis suggests a role for CaR in other cellular functions. Although extracellular Ca(2+) regulates the differentiation of epidermal keratinocytes, the role of CaR in this process in the epidermis is not fully understood. In this study we showed using in situ hybridization and immunohistochemistry that CaR is expressed in suprabasal keratinocytes of the mammalian epidermis. We then evaluated the changes in epidermal keratinocyte morphology and differentiation in Casr(-/-) mice lacking the full-length CaR. These mice show increased expression of an alternatively spliced form of CaR which lacks acute Ca(2+)-signaling properties. The absence of the full-length CaR in the epidermis resulted in ultrastructural changes (abnormal keratohyalin granule formation and precocious lamellar body secretion) in the terminally differentiated granular keratinocytes. Furthermore, the expression of both mRNA and protein for the calcium inducible keratinocyte differentiation markers, filaggrin and loricrin, were down-regulated in the epidermis of Casr(-/-) mice, whereas the number of proliferating cells were increased even though the calcium gradient within the epidermis was enhanced. Our results demonstrate that the epidermal expression of the full-length CaR is required for the normal terminal differentiation of keratinocytes.
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Affiliation(s)
- Laszlo Komuves
- Department of Dermatology, Veterans Affairs Medical Center and the University of California, San Francisco School of Medicine, San Francisco, California 94121, USA
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Abstract
Calcium and 1,25 dihydroxyvitamin D (1,25(OH)(2)D) regulate the differentiation of keratinocytes. We have examined the mechanisms by which such regulation takes place, focusing primarily on the events leading to cornified envelope (CE) formation, in particular the mechanisms by which calcium and 1,25(OH)(2)D regulate the induction of involucrin, a component of the CE, and transglutaminase, the enzyme cross-linking involucrin and other substrates to form the CE. Both extracellular calcium (Ca(o)) and 1,25(OH)(2)D raise intracellular free calcium (Ca(i)) as a necessary step toward stimulating differentiation. Cells lacking the calcium sensing receptor (CaR) or phospholipase C-gamma 1 (PLC-gamma 1) fail to respond to Ca(o) or 1,25(OH)(2)D with respect to differentiation. Residing in the promoter of involucrin is a region responsive to calcium and 1,25(OH)(2)D, the calcium response element (CaRE). The CaRE contains an AP-1 site, mutations of which result in loss of responsiveness to Ca(o) and 1,25(OH)(2)D, indicating a role for protein kinases C (PKC). PKC alpha is the major PKC isozyme involved at least for calcium-induced differentiation. Thus, the regulation of keratinocyte differentiation by calcium and 1,25(OH)(2)D involves a number of signaling pathways including PLC and PKC activation, leading to the induction of proteins required for the differentiation process.
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Affiliation(s)
- D D Bikle
- Department of Medicine, Veterans Affairs Medical Center (111N), University of California, 4150 Clement Street, San Francisco, CA 94121, USA.
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32
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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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