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Lu Y, Chen H, Chen Y, Zhao L, Hou S. Accumulated LPS induced by colitis altered the activities of vitamin D-metabolizing hydroxylases and decreased the generation of 25-hydroxyvitamin D. Chem Biol Interact 2024; 395:110997. [PMID: 38588969 DOI: 10.1016/j.cbi.2024.110997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 04/10/2024]
Abstract
It is generally accepted that low vitamin D (VD) levels are associated with a high prevalence factor for Inflammatory bowel disease (IBD). IBD patients have observed higher levels of lipopolysaccharide (LPS), ALT, and AST than healthy people. Gut-derived LPS causes inflammatory injury in the liver and kidney. The VD-metabolizing mechanism is involved in the liver and kidney, which means IBD might impact VD metabolism. However, whether IBD affects VD metabolism has not been studied. In vitro LPS resulted in decreased CYP2R1 in liver cells as well as decreased CYP27B1 and increased CYP24A1 in kidney cells, revealing that LPS changed the activities of several hydroxylases. Mice with acute colitis had an increased LPS in serum and liver with mild hepatic injuries, while mice with chronic colitis had a significant elevation of LPS in serum, liver, and kidney with hepatorenal injuries. Thus, the liver hydroxylase for VD metabolism would be the first to be affected in IBD. Consequently, serum 25-hydroxyvitamin D declined dramatically with a significant elevation of 24,25-dihydroxyvitamin D and 1,24,25-trihydroxyvitamin D. Unchanged serum levels of 1,25-dihydroxyvitamin D might be the result of other factors in vivo. In acute colitis, a small dosage (4 IU/day) of cholecalciferol could protect the colon, decrease the serum level of LPS, and finally increase serum 25-hydroxyvitamin D. However, this improvement of cholecalciferol was fading in chronic colitis. These results suggested that VD supplementations for preventing and curing IBD in the clinic should consider hepatorenal hydroxylases and be employed as soon as possible for a better outcome.
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Affiliation(s)
- Yingyu Lu
- Shunde Hospital, Southern Medical University, Foshan, 528000, Guangdong, PR China
| | - Hao Chen
- Shunde Hospital, Southern Medical University, Foshan, 528000, Guangdong, PR China
| | - Yonger Chen
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510000, Guangdong, PR China
| | - Liang Zhao
- Shunde Hospital, Southern Medical University, Foshan, 528000, Guangdong, PR China; Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, 510000, Guangdong, PR China.
| | - Shaozhen Hou
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510000, Guangdong, PR China.
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2
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Veeresh PKM, Basavaraju CG, Dallavalasa S, Anantharaju PG, Natraj SM, Sukocheva OA, Madhunapantula SV. Vitamin D3 Inhibits the Viability of Breast Cancer Cells In Vitro and Ehrlich Ascites Carcinomas in Mice by Promoting Apoptosis and Cell Cycle Arrest and by Impeding Tumor Angiogenesis. Cancers (Basel) 2023; 15:4833. [PMID: 37835527 PMCID: PMC10571758 DOI: 10.3390/cancers15194833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023] Open
Abstract
The incidence of aggressive and resistant breast cancers is growing at alarming rates, indicating a necessity to develop better treatment strategies. Recent epidemiological and preclinical studies detected low serum levels of vitamin D in cancer patients, suggesting that vitamin D may be effective in mitigating the cancer burden. However, the molecular mechanisms of vitamin D3 (cholecalciferol, vit-D3)-induced cancer cell death are not fully elucidated. The vit-D3 efficacy of cell death activation was assessed using breast carcinoma cell lines in vitro and a widely used Ehrlich ascites carcinoma (EAC) breast cancer model in vivo in Swiss albino mice. Both estrogen receptor-positive (ER+, MCF-7) and -negative (ER-, MDA-MB-231, and MDA-MB-468) cell lines absorbed about 50% of vit-D3 in vitro over 48 h of incubation. The absorbed vit-D3 retarded the breast cancer cell proliferation in a dose-dependent manner with IC50 values ranging from 0.10 to 0.35 mM. Prolonged treatment (up to 72 h) did not enhance vit-D3 anti-proliferative efficacy. Vit-D3-induced cell growth arrest was mediated by the upregulation of p53 and the downregulation of cyclin-D1 and Bcl2 expression levels. Vit-D3 retarded cell migration and inhibited blood vessel growth in vitro as well as in a chorioallantoic membrane (CAM) assay. The intraperitoneal administration of vit-D3 inhibited solid tumor growth and reduced body weight gain, as assessed in mice using a liquid tumor model. In summary, vit-D3 cytotoxic effects in breast cancer cell lines in vitro and an EAC model in vivo were associated with growth inhibition, the induction of apoptosis, cell cycle arrest, and the impediment of angiogenic processes. The generated data warrant further studies on vit-D3 anti-cancer therapeutic applications.
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Affiliation(s)
- Prashanth Kumar M. Veeresh
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR) Laboratory, Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (P.K.M.V.); (C.G.B.); (S.D.); (P.G.A.); (S.M.N.)
| | - Chaithanya G. Basavaraju
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR) Laboratory, Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (P.K.M.V.); (C.G.B.); (S.D.); (P.G.A.); (S.M.N.)
| | - Siva Dallavalasa
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR) Laboratory, Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (P.K.M.V.); (C.G.B.); (S.D.); (P.G.A.); (S.M.N.)
| | - Preethi G. Anantharaju
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR) Laboratory, Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (P.K.M.V.); (C.G.B.); (S.D.); (P.G.A.); (S.M.N.)
| | - Suma M. Natraj
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR) Laboratory, Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (P.K.M.V.); (C.G.B.); (S.D.); (P.G.A.); (S.M.N.)
| | - Olga A. Sukocheva
- Department of Hepatology, Royal Adelaide Hospital, Port Rd, Adelaide 5000, Australia;
| | - SubbaRao V. Madhunapantula
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR) Laboratory, Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (P.K.M.V.); (C.G.B.); (S.D.); (P.G.A.); (S.M.N.)
- Special Interest Group in Cancer Biology and Cancer Stem Cells (SIG-CBCSC), Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India
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3
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Ueda K, Chin SS, Sato N, Nishikawa M, Yasuda K, Miyasaka N, Bera BS, Chorro L, Doña-Termine R, Koba WR, Reynolds D, Steidl UG, Lauvau G, Greally JM, Suzuki M. Prenatal vitamin D deficiency alters immune cell proportions of young adult offspring through alteration of long-term stem cell fates. bioRxiv 2023:2023.09.11.557255. [PMID: 37745570 PMCID: PMC10515841 DOI: 10.1101/2023.09.11.557255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Vitamin D deficiency is a common deficiency worldwide, particularly among women of reproductive age. During pregnancy, it increases the risk of immune-related diseases in offspring later in life. However, exactly how the body remembers exposure to an adverse environment during development is poorly understood. Herein, we explore the effects of prenatal vitamin D deficiency on immune cell proportions in offspring using vitamin D deficient mice established by dietary manipulation. We show that prenatal vitamin D deficiency alters immune cell proportions in offspring by changing the transcriptional properties of genes downstream of vitamin D receptor signaling in hematopoietic stem and progenitor cells of both the fetus and adults. Further investigations of the associations between maternal vitamin D levels and cord blood immune cell profiles from 75 healthy pregnant women and their term babies also confirm that maternal vitamin D levels significantly affect immune cell proportions in the babies. Thus, lack of prenatal vitamin D, particularly at the time of hematopoietic stem cell migration from the liver to the bone marrow, has long-lasting effects on immune cell proportions. This highlights the importance of providing vitamin D supplementation at specific stages of pregnancy.
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Affiliation(s)
- Koki Ueda
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY, 10461, USA
- Department of Blood Transfusion and Transplantation Immunology, Fukushima Medical University, 1 Hikarigaoka, Fukushima, Fukushima, 960-1295, Japan
| | - Shu Shien Chin
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
| | - Noriko Sato
- Department of Food and Nutrition, Faculty of Human Sciences and Design, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan
| | - Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Naoyuki Miyasaka
- Graduate School of Medical and Dental Sciences, Medical and Dental Sciences, Systemic Organ Regulation, Comprehensive Reproductive Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo
| | - Betelehem Solomon Bera
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
| | - Laurent Chorro
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
| | - Reanna Doña-Termine
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
| | - Wade R Koba
- Department of Radiology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY, 10461, USA
| | - David Reynolds
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
| | - Ulrich G. Steidl
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY, 10461, USA
- Ruth L. and David S. Gottesman Institute for Stem Cell Research and Regenerative Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
- Department of Oncology, Albert Einstein College of Medicine – Montefiore Medical Center, 1300 Morris Park Ave, Bronx, NY 10461, USA
- Montefiore-Einstein Cancer Center, Albert Einstein College of Medicine – Montefiore Medical Center, 1300 Morris Park Ave, Bronx, NY 10461, USA
| | - Gregoire Lauvau
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
| | - John M. Greally
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
- Department of Pediatrics, Albert Einstein College of Medicine – Montefiore Medical Center, 1300 Morris Park Ave, Bronx, NY 10461, USA
| | - Masako Suzuki
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave, Bronx, NY, 10461, USA
- Department of Nutrition, Texas A&M University, 2253 TAMU, College Station, TX, 77840, USA
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4
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Norlin M, Wikvall K. Enzymatic activation in vitamin D signaling - Past, present and future. Arch Biochem Biophys 2023; 742:109639. [PMID: 37196753 DOI: 10.1016/j.abb.2023.109639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/10/2023] [Accepted: 05/14/2023] [Indexed: 05/19/2023]
Abstract
Vitamin D signaling is important in regulating calcium homeostasis essential for bone health but also displays other functions in cells of several tissues. Disturbed vitamin D signaling is linked to a large number of diseases. The multiple cytochrome P450 (CYP) enzymes catalyzing the different hydroxylations in bioactivation of vitamin D3 are crucial for vitamin D signaling and function. This review is focused on the progress achieved in identification of the bioactivating enzymes and their genes in production of 1α,25-dihydroxyvitamin D3 and other active metabolites. Results obtained on species- and tissue-specific expression, catalytic reactions, substrate specificity, enzyme kinetics, and consequences of gene mutations are evaluated. Matters of incomplete understanding regarding the physiological roles of some vitamin D hydroxylases are critically discussed and the authors will give their view of the importance of each enzyme for vitamin D signaling. Roles of different vitamin D receptors and an alternative bioactivation pathway, leading to 20-hydroxylated vitamin D3 metabolites, are also discussed. Considerable progress has been achieved in knowledge of the vitamin D3 bioactivating enzymes. Nevertheless, several intriguing areas deserve further attention to understand the pleiotropic and diverse activities elicited by vitamin D signaling and the mechanisms of enzymatic activation necessary for vitamin D-induced responses.
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Affiliation(s)
- Maria Norlin
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.
| | - Kjell Wikvall
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
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Zamanfar D, Ghazaiean M. An overview of CYP27B1 enzyme mutation and management: A case report and review of the literature. Clin Case Rep 2023; 11:e7007. [PMID: 36879673 PMCID: PMC9984874 DOI: 10.1002/ccr3.7007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/07/2023] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Vitamin D-dependent rickets type 1 (VDDRIA) is an autosomal recessive disorder caused by mutations in the Cytochrome P450 Family 27 Subfamily B Member 1 (CYP27B1) gene, which encodes for the enzyme 1 alpha-hydroxylase. We report a known case of VDDRIA with hypotonia, growth and developmental disorders and discuss about the mutation and its management.
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Affiliation(s)
- Daniel Zamanfar
- Pediatric Endocrinologist, Diabetes Research Center of Mazandaran Mazandaran University of Medical Sciences Sari Iran
| | - Mobin Ghazaiean
- Student Research Committee Mazandaran University of Medical Sciences Sari Iran
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Nishikawa M, Murose N, Mano H, Yasuda K, Isogai Y, Kittaka A, Takano M, Ikushiro S, Sakaki T. Robust osteogenic efficacy of 2α-heteroarylalkyl vitamin D analogue AH-1 in VDR (R270L) hereditary vitamin D-dependent rickets model rats. Sci Rep 2022; 12:12517. [PMID: 35869242 PMCID: PMC9307643 DOI: 10.1038/s41598-022-16819-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 07/15/2022] [Indexed: 11/09/2022] Open
Abstract
Active vitamin D form 1α,25-dihydroxtvitamin D3 (1,25(OH)2D3) plays pivotal roles in calcium homeostasis and osteogenesis via its transcription regulation effect via binding to vitamin D receptor (VDR). Mutated VDR often causes hereditary vitamin D-dependent rickets (VDDR) type II, and patients with VDDR-II are hardly responsive to physiological doses of 1,25(OH)D3. Current therapeutic approaches, including high doses of oral calcium and supraphysiologic doses of 1,25(OH)2D3, have limited success and fail to improve the quality of life of affected patients. Thus, various vitamin D analogues have been developed as therapeutic options. In our previous study, we generated genetically modified rats with mutated Vdr(R270L), an ortholog of human VDR(R274L) isolated from the patients with VDDR-II. The significant reduced affinity toward 1,25(OH)2D3 of rat Vdr(R270L) enabled us to evaluate biological activities of exogenous VDR ligand without 1α-hydroxy group such as 25(OH)D3. In this study, 2α-[2-(tetrazol-2-yl)ethyl]-1α,25(OH)2D3 (AH-1) exerted much higher affinity for Vdr(R270L) in in vitro ligand binding assay than both 25(OH)D3 and 1,25(OH)2D3. A robust osteogenic activity of AH-1 was observed in Vdr(R270L) rats. Only a 40-fold lower dose of AH-1 than that of 25(OH)D3 was effective in ameliorating rickets symptoms in Vdr(R270L) rats. Therefore, AH-1 may be promising for the therapy of VDDR-II with VDR(R274L).
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7
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Yasuda K, Nishikawa M, Mano H, Takano M, Kittaka A, Ikushiro S, Sakaki T. Development of In Vitro and In Vivo Evaluation Systems for Vitamin D Derivatives and Their Application to Drug Discovery. Int J Mol Sci 2021; 22:ijms222111839. [PMID: 34769269 PMCID: PMC8584323 DOI: 10.3390/ijms222111839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/30/2022] Open
Abstract
We have developed an in vitro system to easily examine the affinity for vitamin D receptor (VDR) and CYP24A1-mediated metabolism as two methods of assessing vitamin D derivatives. Vitamin D derivatives with high VDR affinity and resistance to CYP24A1-mediated metabolism could be good therapeutic agents. This system can effectively select vitamin D derivatives with these useful properties. We have also developed an in vivo system including a Cyp27b1-gene-deficient rat (a type I rickets model), a Vdr-gene-deficient rat (a type II rickets model), and a rat with a mutant Vdr (R270L) (another type II rickets model) using a genome editing method. For Cyp27b1-gene-deficient and Vdr mutant (R270L) rats, amelioration of rickets symptoms can be used as an index of the efficacy of vitamin D derivatives. Vdr-gene-deficient rats can be used to assess the activities of vitamin D derivatives specialized for actions not mediated by VDR. One of our original vitamin D derivatives, which displays high affinity VDR binding and resistance to CYP24A1-dependent metabolism, has shown good therapeutic effects in Vdr (R270L) rats, although further analysis is needed.
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Affiliation(s)
- Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (K.Y.); (H.M.)
| | - Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (M.N.); (S.I.)
| | - Hiroki Mano
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (K.Y.); (H.M.)
| | - Masashi Takano
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo 173-8605, Japan; (M.T.); (A.K.)
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo 173-8605, Japan; (M.T.); (A.K.)
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (M.N.); (S.I.)
| | - Toshiyuki Sakaki
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (K.Y.); (H.M.)
- Correspondence:
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Kaygusuz SB, Alavanda C, Kirkgoz T, Eltan M, Yavas Abali Z, Helvacioglu D, Guran T, Ata P, Bereket A, Turan S. Does Genotype-Phenotype Correlation Exist in Vitamin D-Dependent Rickets Type IA: Report of 13 New Cases and Review of the Literature. Calcif Tissue Int 2021; 108:576-586. [PMID: 33386952 DOI: 10.1007/s00223-020-00784-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/28/2020] [Indexed: 11/28/2022]
Abstract
Vitamin D-dependent rickets type IA (VDDR-IA) is caused by biallelic mutations in CYP27B1. Data regarding genotype-phenotype correlation in VDDR-IA are scarce. Here, we aimed to investigate clinical/genotypic features and long-term follow-up of 13 new cases with VDDR-IA and genotype-phenotype correlation of reported cases in the literature. Thirteen patients with VDDR-IA were evaluated. Eight patients had reached their final height at the time of the study and, for whom, long-term outcome data were analyzed. Further, all VDDR-IA patients in the literature (n:183) were analyzed and clinical-genetic features were recorded. The median age of diagnosis was 2.55 ± 1.13 (1.0-12) years. Initial diagnoses before referral to our clinic were nutritional rickets (n:7), hypophosphatemic rickets (n:2), and pseudohypoparathyroidism (n:1). All had biochemical evidence suggestive of VDDR-IA; except one with elevated 1,25(OH)2D3 and another with hyperphosphatemia, in whom pseudohypoparathyroidism was excluded with molecular tests. Combined analyses of our cohort and other series in the literature demonstrated that three most common CYP27B1 mutations are p.F443Pfs*24, c.195 + 2T > G, and p.V88Wfs*71. In Turkish population, p.K192E mutation along with the former two is the most common mutations. Comparison of clinical features demonstrated that c.195 + 2T > G mutation causes the most severe and p.K192E mutation causes the least severe phenotype with respect to age and height at presentation and calcitriol requirement. We found a clear genotype-phenotype correlation in VDDR-IA, notably CYP27B1 intronic c.195 + 2T > G mutation causes a more severe phenotype with lower height SDS at presentation and, higher calcitriol requirement, while less severe phenotype occurs in p.K192E mutation.
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Affiliation(s)
- Sare Betul Kaygusuz
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Ceren Alavanda
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Tarik Kirkgoz
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Mehmet Eltan
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Zehra Yavas Abali
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Didem Helvacioglu
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Tulay Guran
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Pinar Ata
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Abdullah Bereket
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Serap Turan
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey.
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Yasuda K, Nishikawa M, Okamoto K, Horibe K, Mano H, Yamaguchi M, Okon R, Nakagawa K, Tsugawa N, Okano T, Kawagoe F, Kittaka A, Ikushiro S, Sakaki T. Elucidation of metabolic pathways of 25-hydroxyvitamin D3 mediated by CYP24A1 and CYP3A using Cyp24a1 knockout rats generated by CRISPR/Cas9 system. J Biol Chem 2021; 296:100668. [PMID: 33865853 PMCID: PMC8134072 DOI: 10.1016/j.jbc.2021.100668] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/25/2021] [Accepted: 04/13/2021] [Indexed: 01/27/2023] Open
Abstract
CYP24A1-deficient (Cyp24a1 KO) rats were generated using the CRISPER/Cas9 system to investigate CYP24A1-dependent or -independent metabolism of 25(OH)D3, the prohormone of calcitriol. Plasma 25(OH)D3 concentrations in Cyp24a1 KO rats were approximately twofold higher than in wild-type rats. Wild-type rats showed five metabolites of 25(OH)D3 in plasma following oral administration of 25(OH)D3, and these metabolites were not detected in Cyp24a1 KO rats. Among these metabolites, 25(OH)D3-26,23-lactone was identified as the second major metabolite with a significantly higher Tmax value than others. When 23S,25(OH)2D3 was administered to Cyp24a1 KO rats, neither 23,25,26(OH)3D3 nor 25(OH)D3-26,23-lactone was observed. However, when 23S,25R,26(OH)3D3 was administered to Cyp24a1 KO rats, plasma 25(OH)D3-26,23-lactone was detected. These results suggested that CYP24A1 is responsible for the conversion of 25(OH)D3 to 23,25,26(OH)3D3 via 23,25(OH)2D3, but enzyme(s) other than CYP24A1 may be involved in the conversion of 23,25,26(OH)3D3 to 25(OH)D3-26,23-lactone. Enzymatic studies using recombinant human CYP species and the inhibitory effects of ketoconazole suggested that CYP3A plays an essential role in the conversion of 23,25,26(OH)3D3 into 25(OH)D3-26,23-lactone in both rats and humans. Taken together, our data indicate that Cyp24a1 KO rats are valuable for metabolic studies of vitamin D and its analogs. In addition, long-term administration of 25(OH)D3 to Cyp24a1 KO rats at 110 μg/kg body weight/day resulted in significant weight loss and ectopic calcification. Thus, Cyp24a1 KO rats could represent an important model for studying renal diseases originating from CYP24A1 dysfunction.
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Affiliation(s)
- Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Kairi Okamoto
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Kyohei Horibe
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Hiroki Mano
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Mana Yamaguchi
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Risa Okon
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Kimie Nakagawa
- Laboratory of Hygienic Sciences, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Chuo-ku, Kobe, Japan
| | - Naoko Tsugawa
- Department of Health and Nutrition, Faculty of Health and Nutrition, Osaka Shoin Women's University, Higashi-Osaka, Japan
| | - Toshio Okano
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Higashinada-ku, Kobe, Japan
| | - Fumihiro Kawagoe
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Toshiyuki Sakaki
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan.
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10
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Barratt KR, Sawyer RK, Atkins GJ, St-Arnaud R, Anderson PH. Vitamin D supplementation improves bone mineralisation independent of dietary phosphate in male X-linked hypophosphatemic (Hyp) mice. Bone 2021; 143:115767. [PMID: 33232838 DOI: 10.1016/j.bone.2020.115767] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 12/21/2022]
Abstract
The disorder of X-linked hypophosphatemia (XLH), results in the supressed renal production of active 1α,25-dihydroxyvitamin D (1,25(OH)2D) due to elevated fibroblast growth factor-23 (FGF23) levels. While adequate 25(OH)D levels are generally associated with improved mineralisation of the skeleton independent of circulating 1,25(OH)2D levels, it is unclear whether raising 25(OH)D to sufficiently high levels through dietary vitamin D3 administration contributes to improving bone mineralisation in the murine homolog for XLH, Hyp mice. Three-week-old male Hyp mice were fed one of four diets containing either 1000 IU (C) or 20,000 IU (D) vitamin D3/kg diet with either 0.35% phosphate or 1.25% phosphate (P) until 12 weeks of age (n = 12/group). When compared to C-fed mice, D-fed mice significantly elevated serum 25(OH)D levels to 72.8 ± 4.9 nmol/L (2-fold, p < 0.001) and increased both cortical bone mineral density (15%, p < 0.01), and vertebral trabecular BV/TV% (80%, p < 0.001), despite persistent hypophosphatemia and normocalcemia. The increase in bone volume was associated with improved Tb.Th (12%, p < 0.01) and Tb.N (63%, p < 0.001). Unlike with D-diet, P-fed mice resulted in increased femoral (15%, p < 0.001) and vertebral (12%, p < 0.001) length, and a 34% increase in vertebral trabecular BV/TV% when compared to control fed animals (p < 0.001). However, the addition of the high P diet to the high D diet did not result in additive effects on bone mineralisation when compared to the effects of D diet alone, despite serum 25(OH)D levels elevated to 118.8 ± 8.6 nmol/L. In D-fed mice, the increase in bone mineral density and volume was associated with reduced osteoid volume, reduced ObS/BS, and a trend for reduced serum PTH levels, suggesting reduced bone turnover in these animals. Thus, elevating serum 25(OH)D levels independently improves bone mineralisation in Hyp mice without causing hypercalcemia, suggesting that further studies are required in XLH patients to establish the role of increasing 25(OH)D levels in improving bone mineralisation.
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Affiliation(s)
- Kate R Barratt
- University of South Australia, Clinical and Health Sciences, Health and Biomedical Innovation, Adelaide, SA 5000, Australia.
| | - Rebecca K Sawyer
- University of South Australia, Clinical and Health Sciences, Health and Biomedical Innovation, Adelaide, SA 5000, Australia.
| | - Gerald J Atkins
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA 5000, Australia.
| | - Rene St-Arnaud
- Shriners Hospitals for Children - Canada and McGill University, Montreal, QC H4A 0A9, Canada.
| | - Paul H Anderson
- University of South Australia, Clinical and Health Sciences, Health and Biomedical Innovation, Adelaide, SA 5000, Australia.
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11
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Hayashi H, Okamatsu M, Ogasawara H, Tsugawa N, Isoda N, Matsuno K, Sakoda Y. Oral Supplementation of the Vitamin D Metabolite 25(OH)D 3 Against Influenza Virus Infection in Mice. Nutrients 2020; 12:E2000. [PMID: 32635656 DOI: 10.3390/nu12072000] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/22/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022] Open
Abstract
Vitamin D is a fat-soluble vitamin that is metabolized by the liver into 25-hydroxyvitamin D [25(OH)D] and then by the kidney into 1,25-dihydroxyvitamin D [1,25(OH)2D], which activates the vitamin D receptor expressed in various cells, including immune cells, for an overall immunostimulatory effect. Here, to investigate whether oral supplementation of 25-hydroxyvitamin D3 [25(OH)D3], a major form of vitamin D metabolite 25(OH)D, has a prophylactic effect on influenza A virus infection, mice were fed a diet containing a high dose of 25(OH)D3 and were challenged with the influenza virus. In the lungs of 25(OH)D3-fed mice, the viral titers were significantly lower than in the lungs of standardly fed mice. Additionally, the proinflammatory cytokines IL-5 and IFN-γ were significantly downregulated after viral infection in 25(OH)D3-fed mice, while anti-inflammatory cytokines were not significantly upregulated. These results indicate that 25(OH)D3 suppresses the production of inflammatory cytokines and reduces virus replication and clinical manifestations of influenza virus infection in a mouse model.
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12
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Kikuyama T, Susa T, Tamamori-Adachi M, Iizuka M, Akimoto M, Okinaga H, Fujigaki Y, Uchida S, Shibata S, Okazaki T. 25(OH)D 3 stimulates the expression of vitamin D target genes in renal tubular cells when Cyp27b1 is abrogated. J Steroid Biochem Mol Biol 2020; 199:105593. [PMID: 31945466 DOI: 10.1016/j.jsbmb.2020.105593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 12/28/2022]
Abstract
Recently, it was reported that 25(OH)D3 (25D3) has physiological bioactivity in certain tissues derived from Cyp27b1 knockout mice. To investigate the function of 25D3 in the kidney as an informational crossroad of various calciotropic substances, we employed the CRISPR-Cas9 system to knock out Cyp27b1 in the mouse renal distal tubular mDCT cell line. Unlike the previously reported mice in which Cyp27b1 was targeted systemically, Cyp27b1 knockout mDCT cells did not produce any measurable 1α,25(OH)2D3 (1,25D3) after 25D3 administration. As was seen with treatment of Cyp27b1 knockout mDCT cells with ≥10-8 M of 1,25D3, the administration of 10-7 M of 25D3 translocated the vitamin D3 receptor (VDR) into the nucleus and promoted the expression of the representative 1,25D3-responsive gene Cyp24a1. The exhaustive target gene profiles of 25D3 were similar to those of 1,25D3. Subsequently, we confirmed that 25D3 induced the expression of the calcium reabsorption-related gene calbindin-D9K, in a way similar to 1,25D3. We also found that 1,25D3 and 25D3 induced the expression of the megalin gene. A chromatin immunoprecipitation assay identified two vitamin D response elements in the upstream region of the megalin gene that seemed to contribute to its expression. Together, we surmise that the ability of 25D3 to stimulate VDR target genes may provide a novel perspective for its role in certain tissues.
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Affiliation(s)
- Takahiro Kikuyama
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Takao Susa
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan.
| | | | - Masayoshi Iizuka
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
| | - Miho Akimoto
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
| | - Hiroko Okinaga
- Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshihide Fujigaki
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shunya Uchida
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan.
| | - Tomoki Okazaki
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
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13
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Nishikawa M, Yasuda K, Takamatsu M, Abe K, Okamoto K, Horibe K, Mano H, Nakagawa K, Tsugawa N, Hirota Y, Horie T, Hinoi E, Okano T, Ikushiro S, Sakaki T. Generation of novel genetically modified rats to reveal the molecular mechanisms of vitamin D actions. Sci Rep 2020; 10:5677. [PMID: 32231239 PMCID: PMC7105495 DOI: 10.1038/s41598-020-62048-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 02/18/2020] [Indexed: 11/09/2022] Open
Abstract
Recent studies have suggested that vitamin D activities involve vitamin D receptor (VDR)-dependent and VDR-independent effects of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 25-hydroxyvitamin D3 (25(OH)D3) and ligand-independent effects of the VDR. Here, we describe a novel in vivo system using genetically modified rats deficient in the Cyp27b1 or Vdr genes. Type II rickets model rats with a mutant Vdr (R270L), which recognizes 1,25(OH)2D3 with an affinity equivalent to that for 25(OH)D3, were also generated. Although Cyp27b1-knockout (KO), Vdr-KO, and Vdr (R270L) rats each showed rickets symptoms, including abnormal bone formation, they were significantly different from each other. Administration of 25(OH)D3 reversed rickets symptoms in Cyp27b1-KO and Vdr (R270L) rats. Interestingly, 1,25(OH)2D3 was synthesized in Cyp27b1-KO rats, probably by Cyp27a1. In contrast, the effects of 25(OH)D3 on Vdr (R270L) rats strongly suggested a direct action of 25(OH)D3 via VDR-genomic pathways. These results convincingly suggest the usefulness of our in vivo system.
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Affiliation(s)
- Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Masashi Takamatsu
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Keisuke Abe
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kairi Okamoto
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kyohei Horibe
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Hiroki Mano
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kimie Nakagawa
- Department of Hygienic Sciences, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Naoko Tsugawa
- Department of Health and Nutrition, Faculty of Health and Nutrition, Osaka Shoin Women's University, 4-2-26 Hishiya-nishi, Higashi-Osaka, 577-8550, Japan
| | - Yoshihisa Hirota
- Laboratory of Biochemistry, Faculty of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama, 337-8570, Japan
| | - Tetsuhiro Horie
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Eiichi Hinoi
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan.,United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Toshio Okano
- Department of Hygienic Sciences, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Toshiyuki Sakaki
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.
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Abstract
The interest in vitamin D continues unabated with thousands of publications contributing to a vast and growing literature each year. It is widely recognized that the vitamin D receptor (VDR) and the enzymes that metabolize vitamin D are found in many cells, not just those involved with calcium and phosphate homeostasis. In this mini review I have focused primarily on recent studies that provide new insights into vitamin D metabolism, mechanisms of action, and clinical applications. In particular, I examine how mutations in vitamin D metabolizing enzymes—and new information on their regulation—links vitamin D metabolism into areas such as metabolism and diseases outside that of the musculoskeletal system. New information regarding the mechanisms governing the function of the VDR elucidates how this molecule can be so multifunctional in a cell-specific fashion. Clinically, the difficulty in determining vitamin D sufficiency for all groups is addressed, including a discussion of whether the standard measure of vitamin D sufficiency, total 25OHD (25 hydroxyvitamin) levels, may not be the best measure—at least by itself. Finally, several recent large clinical trials exploring the role of vitamin D supplementation in nonskeletal diseases are briefly reviewed, with an eye toward what questions they answered and what new questions they raised.
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Affiliation(s)
- Daniel D Bikle
- Department of Medicine and Endocrine Research Unit, Veterans Affairs Medical Center and University of California, San Francisco, California
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15
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Anaparti V, Meng X, Hemshekhar M, Smolik I, Mookherjee N, El-Gabalawy H. Circulating levels of free 25(OH)D increase at the onset of rheumatoid arthritis. PLoS One 2019; 14:e0219109. [PMID: 31557191 DOI: 10.1371/journal.pone.0219109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/03/2019] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE Epidemiological studies suggest vitamin D deficiency as a potential risk factor for rheumatoid arthritis (RA) development, a chronic autoimmune disorder highly prevalent in indigenous North American (INA) population. We therefore profiled the circulating levels of 25-hydroxyvitaminD [25(OH)D], an active metabolite of vitamin D, in a cohort of at-risk first-degree relatives (FDR) of INA RA patients, a subset of whom subsequently developed RA (progressors). METHODS 2007 onward, serum samples from INA RA patients and FDR were collected at the time of a structured baseline visit and stored at -20°C. Anti-citrullinated protein antibodies (ACPA), 25(OH)D, hs-CRP, vitamin-D binding protein (VDBP) and parathyroid hormone (PTH) levels were determined using ELISA and rheumatoid factor (RF) seropositivity was determined by nephelometry. RESULTS We demonstrate that 25 (OH) D concentrations were lower in winter than summer (P = 0.0538), and that serum 25(OH)D levels were higher in samples collected and stored after 2013 (P<0.0001). Analysis of samples obtained after 2013 demonstrated that 37.6% of study participants were 25(OH)D insufficient (<75nmol/L). Also, seropositive RA patients and FDR had lower 25(OH)D levels compared to ACPA-/FDR (P<0.05, P<0.01 respectively). Linear regression analysis showed 25(OH)D insufficiency was inversely associated with presence of RA autoantibodies. Longitudinal samples from 14 progressors demonstrated a consistent increase in 25(OH)D levels at the time they exhibited clinically detectable joint inflammation, without any significant change in VDBP or PTH levels. Spearman rank correlation analysis showed significant association between 25(OH)D and PTH levels, both in RA patients and progressors at RA onset time. CONCLUSION We demonstrate that 25(OH)D levels in serum increased at RA onset in progressors. The potential role that vitamin D metabolites and their downstream effects play in RA transition requires further investigation.
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Abstract
OBJECTIVE Vitamin D dependent rickets type 1A (VDDR1A) is an autosomal recessive disorder caused by mutations in the 1α-hydroxylase gene (CYB27B1). As it may be confused with nutritional rickets and hypophosphatemic rickets, genetic analysis is important for making a correct diagnosis. METHODS We analysed genomic DNA from 11 patients from eight different Turkish families. The patients were recruited for our studies if they presented with a diagnosis of VDDR. RESULTS The mean ± standard deviation age at diagnosis was 13.1±7.4 months. Seven patients had mild hypocalcemia at presentation while four patients had normal calcium concentrations. All patients underwent CYP27B1 gene analysis. The most prevalent mutation was the c.195 + 2T>G splice donor site mutation, affecting five out of 11 patients with VDDR1A. Two patients from the fourth family were compound heterozygous for c.195 + 2T>G and c.195 + 2 T>A in intron-1. Two patients, from different families, were homozygous for a previously reported duplication mutation in exon 8 (1319_1325dupCCCACCC, Phe443Profs*24). One patient had a homozygous splice site mutation in intron 7 (c.1215 + 2 T>A) and one patient had a homozygous mutation in exon 9 (c.1474 C>T). CONCLUSION Intron-1 mutation was the most common mutation, as previously reported. All patients carrying that mutation were from same city of origin suggesting a “founder” or a “common ancestor” effect. VDDR1A should definitely be considered when a patient with signs of rickets has a normal 25-OHD level or when there is unresponsiveness to vitamin D treatment.
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Affiliation(s)
- Fatma Dursun
- Ümraniye Training and Research Hospital, Clinic of Pediatric Endocrinology, İstanbul, Turkey,* Address for Correspondence: Ümraniye Training and Research Hospital, Clinic of Pediatric Endocrinology, İstanbul, Turkey Phone: +90 505 267 14 03 E-mail:
| | - Gamze Özgürhan
- Süleymaniye Maternity and Children’s Training and Research Hospital, Clinic of Paediatrics, İstanbul, Turkey
| | - Heves Kırmızıbekmez
- Ümraniye Training and Research Hospital, Clinic of Pediatric Endocrinology, İstanbul, Turkey
| | - Ece Keskin
- Süleymaniye Maternity and Children’s Training and Research Hospital, Clinic of Medical Genetic, İstanbul, Turkey
| | - Bülent Hacıhamdioğlu
- İstinye University Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
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