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Vitamin D-Mediated Regulation of Intestinal Calcium Absorption. Nutrients 2022; 14:nu14163351. [PMID: 36014856 PMCID: PMC9416674 DOI: 10.3390/nu14163351] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/27/2022] Open
Abstract
Vitamin D is a critical regulator of calcium and bone homeostasis. While vitamin D has multiple effects on bone and calcium metabolism, the regulation of intestinal calcium (Ca) absorption efficiency is a critical function for vitamin D. This is necessary for optimal bone mineralization during growth, the protection of bone in adults, and the prevention of osteoporosis. Intestinal Ca absorption is regulated by 1,25 dihydroxyvitamin D (1,25(OH)2 D), a hormone that activates gene transcription following binding to the intestinal vitamin D receptor (VDR). When dietary Ca intake is low, Ca absorption follows a vitamin-D-regulated, saturable pathway, but when dietary Ca intake is high, Ca absorption is predominately through a paracellular diffusion pathway. Deletion of genes that mediate vitamin D action (i.e., VDR) or production (CYP27B1) eliminates basal Ca absorption and prevents the adaptation of mice to low-Ca diets. Various physiologic or disease states modify vitamin-D-regulated intestinal absorption of Ca (enhanced during late pregnancy, reduced due to menopause and aging).
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Verlinden L, Carmeliet G. Integrated View on the Role of Vitamin D Actions on Bone and Growth Plate Homeostasis. JBMR Plus 2021; 5:e10577. [PMID: 34950832 PMCID: PMC8674772 DOI: 10.1002/jbm4.10577] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/22/2021] [Accepted: 10/31/2021] [Indexed: 12/12/2022] Open
Abstract
1,25(OH)2D3, the biologically active form of vitamin D3, is a major regulator of mineral and bone homeostasis and exerts its actions through binding to the vitamin D receptor (VDR), a ligand‐activated transcription factor that can directly modulate gene expression in vitamin D‐target tissues such as the intestine, kidney, and bone. Inactivating VDR mutations or vitamin D deficiency during development results in rickets, hypocalcemia, secondary hyperparathyroidism, and hypophosphatemia, pointing to the critical role of 1,25(OH)2D3‐induced signaling in the maintenance of mineral homeostasis and skeletal health. 1,25(OH)2D3 is a potent stimulator of VDR‐mediated intestinal calcium absorption, thus increasing the availability of calcium required for proper bone mineralization. However, when intestinal calcium absorption is impaired, renal calcium reabsorption is increased and calcium is mobilized from the bone to preserve normocalcemia. Multiple cell types within bone express the VDR, thereby allowing 1,25(OH)2D3 to directly affect bone homeostasis. In this review, we will discuss different transgenic mouse models with either Vdr deletion or overexpression in chondrocytes, osteoblasts, osteocytes, or osteoclasts to delineate the direct effects of 1,25(OH)2D3 on bone homeostasis. We will address the bone cell type–specific effects of 1,25(OH)2D3 in conditions of a positive calcium balance, where the amount of (re)absorbed calcium equals or exceeds fecal and renal calcium losses, as well as during a negative calcium balance, due to selective Vdr knockdown in the intestine or triggered by a low calcium diet. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Lieve Verlinden
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism KU Leuven Leuven Belgium
| | - Geert Carmeliet
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism KU Leuven Leuven Belgium
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Abstract
Extracellular calcium is normally tightly regulated by parathyroid hormone (PTH), 1,25-dihydroxyvitamin D, as well as by calcium ion (Ca++) itself. Dysregulated PTH production leading to hypercalcemia occurs most commonly in sporadic primary hyperparathryoidism (PHPT) but may also result from select genetic mutations in familial disorders. Parathyroid hormone-related protein shares molecular mechanisms of action with PTH and is the most common cause of hypercalcemia of malignancy. Other cytokines and mediators may also cause resorptive hypercalcemia once bone metastases have occurred. Less commonly, extrarenal production of calcitriol can occur in malignancies and in infectious and noninfectious inflammatory conditions and can cause hypercalcemia.
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Affiliation(s)
- David Goltzman
- Calcium Research Laboratory, Department of Medicine and Physiology, McGill University, Research Institute of the McGill University Health Centre, Glen Site, 1001 Decarie Boulevard, Room EM1.3220, Montreal, Quebec H4A 3J1, Canada.
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Ono-Ohmachi A, Ishida Y, Morita Y, Kato K, Yamanaka H, Masuyama R. Bone mass protective potential mediated by bovine milk basic protein requires normal calcium homeostasis in mice. Nutrition 2021; 91-92:111409. [PMID: 34388585 DOI: 10.1016/j.nut.2021.111409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 06/21/2021] [Accepted: 06/25/2021] [Indexed: 11/24/2022]
Abstract
OBJECTIVES Milk provide protective effects against bone loss caused by an impaired calcium balance. Although the effects of some elements have previously been confirmed, the involvement of milk basic protein (MBP) in bone mineral metabolism remains poorly characterized. Moreover, the importance of mineral nutrition sufficiency to establish the effect of MBP must be evaluated. METHODS First, to evaluate the physiological conditions required for MBP activity, we examined the bone and mineral phenotypes of mice that suffer from insufficient calcium absorption due to a lack of intestinal vitamin D signaling. Second, to determine whether vitamin D signaling affects the effect of MBP on bone resorption, in vitro osteoclastogenesis were assessed using bone marrow cells. RESULTS In mice with systemic vitamin D receptor (Vdr) inactivation, dietary MBP supplementation was unable to normalize hypercalcemia and hyperparathyroidism and failed to rescue bone mineralization impairments. In contrast, calcium and bone homeostasis responded to MBP supplementation when Vdr inactivation was restricted to the intestines. Hyperparathyroidism in intestine-specific Vdr knockout mice was also improved by MBP supplementation, along with a decrease in bone resorption in response to the level of serum tartrate-resistant acid phosphatase 5b. These results corresponded with a reduction in tartrate-resistant acid phosphatase-stained osteoclast numbers and the eroded surface on the tibia. MBP treatment dose-dependently suppressed osteoclastogenesis in cultured bone marrow macrophages regardless of vitamin D activity. These effects of MBP were blunted when parathyroid hormone was added to the culture medium, which is in line with the in vivo phenotype observed with systemic Vdr inactivation and suggests that severe hyperparathyroidism limits MBP activity in the bone. CONCLUSIONS Therefore, adaptive calcium homeostasis is an essential requirement when MBP exerts protective effects through the inhibition of bone resorption.
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Affiliation(s)
- Aiko Ono-Ohmachi
- Milk Science Research Institute, Megmilk Snow Brand Co., Ltd., Saitama, Japan; Department of Quality Assurance, Bean Stalk Snow Co., Ltd., Tokyo, Japan
| | - Yuko Ishida
- Milk Science Research Institute, Megmilk Snow Brand Co., Ltd., Saitama, Japan
| | - Yoshikazu Morita
- Milk Science Research Institute, Megmilk Snow Brand Co., Ltd., Saitama, Japan
| | - Ken Kato
- Milk Science Research Institute, Megmilk Snow Brand Co., Ltd., Saitama, Japan
| | - Hitoki Yamanaka
- Research Center for Support to Advanced Science, Shinshu University, Nagano, Japan
| | - Ritsuko Masuyama
- Department of Molecular Bone Biology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; Ritsumeikan University, Graduate school of Gastronomy Management, Shiga, Japan
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Li XL, Xu F, Lin FH, Ai LZ, Zhao YJ, Bi XL, Sui L, Zhang Y. A Naringin- and Icariin-Contained Herbal Formula, Gushukang, Ameliorated Aged Osteoporosis of Aged Mice with High Calcium Intake. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2021; 48:1671-1691. [PMID: 33249854 DOI: 10.1142/s0192415x20500834] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Traditional herbal formula Gushukang (GSK) was clinically applied to treat primary osteoporosis and showed osteoprotective effect in ovariectomized rodent animals and regulatory action on calcium transporters. This study aimed to determine if GSK could ameliorate aged osteoporosis by modulating serum level of calciotropic hormones and improving calcium balance. 18-month-old male mice were orally administered with either GSK (0.38[Formula: see text]g/kg body weight) or calcitriol (1[Formula: see text][Formula: see text]g/kg body weight) combined with high calcium diet (HCD, 1.2% Ca) for 60 days. The aged mice fed with normal calcium diet (NCD, 0.6% Ca) were a negative control. Trabecular bone and cortical bone properties as well as calcium balance were determined. Treatment with GSK significantly increased 25(OH)D and 1,25-(OH)2D levels in serum, moreover, it markedly attenuated trabecular bone micro-architectural deteriorations and elevated trabecular bone mass as well as strengthened cortical bone mechanical properties shown by the increase in maximal bending load and elastic modulus. Calcium balance, including urinary Ca excretion, fecal Ca level and net calcium retention, was remarkably improved by GSK, which up-regulated TRPV6 expression in duodenum and TRPV5 expression in kidney and down-regulated claudin-14 expression in duodenum and kidney. Additionally, 1-OHase and 24-OHase expression was significantly decreased (vs. NCD group) and increased (vs. HCD group), respectively, in kidney of GSK- and calcitriol-treated mice. Taken together, this study demonstrated the ameliorative effects of Gushukang on aged osteoporosis by effectively stimulating vitamin D production and improving calcium balance of aged mice with high dietary calcium supplement.
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Affiliation(s)
- Xiao-Li Li
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China
| | - Fei Xu
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China
| | - Fu-Hui Lin
- Department of Orthopaedic, Shenzhen Pingle Orthopaedic Hospital, Shenzhen 518000, P. R. China
| | - Lian-Zhong Ai
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China
| | - Yong-Jian Zhao
- Spine Disease Research Institute, Longhua Hospital, Shanghai University of Traditional, Chinese Medicine, Shanghai 200032, P. R. China
| | - Xiao-Lei Bi
- Liaoning Konruns Pharmaceutical Co., Ltd, Dandong 118301, P. R. China
| | - Li Sui
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China
| | - Yan Zhang
- Spine Disease Research Institute, Longhua Hospital, Shanghai University of Traditional, Chinese Medicine, Shanghai 200032, P. R. China
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Giustina A, Adler RA, Binkley N, Bollerslev J, Bouillon R, Dawson-Hughes B, Ebeling PR, Feldman D, Formenti AM, Lazaretti-Castro M, Marcocci C, Rizzoli R, Sempos CT, Bilezikian JP. Consensus statement from 2 nd International Conference on Controversies in Vitamin D. Rev Endocr Metab Disord 2020; 21:89-116. [PMID: 32180081 PMCID: PMC7113202 DOI: 10.1007/s11154-019-09532-w] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The 2nd International Conference on Controversies in Vitamin D was held in Monteriggioni (Siena), Italy, September 11-14, 2018. The aim of this meeting was to address ongoing controversies and timely topics in vitamin D research, to review available data related to these topics and controversies, to promote discussion to help resolve lingering issues and ultimately to suggest a research agenda to clarify areas of uncertainty. Several issues from the first conference, held in 2017, were revisited, such as assays used to determine serum 25-hydroxyvitamin D [25(OH)D] concentration, which remains a critical and controversial issue for defining vitamin D status. Definitions of vitamin D nutritional status (i.e. sufficiency, insufficiency and deficiency) were also revisited. New areas were reviewed, including vitamin D threshold values and how they should be defined in the context of specific diseases, sources of vitamin D and risk factors associated with vitamin D deficiency. Non-skeletal aspects related to vitamin D were also discussed, including the reproductive system, neurology, chronic kidney disease and falls. The therapeutic role of vitamin D and findings from recent clinical trials were also addressed. The topics were considered by 3 focus groups and divided into three main areas: 1) "Laboratory": assays and threshold values to define vitamin D status; 2) "Clinical": sources of vitamin D and risk factors and role of vitamin D in non-skeletal disease and 3) "Therapeutics": controversial issues on observational studies and recent randomized controlled trials. In this report, we present a summary of our findings.
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Affiliation(s)
- A Giustina
- Chair of Endocrinology, School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Endocrinology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - R A Adler
- McGuire Veterans Affairs Medical Center and Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - N Binkley
- Osteoporosis Clinical Research Program and Institute on Aging, University of Wisconsin-Madison, Madison, WI, USA
| | - J Bollerslev
- Section of Specialized Endocrinology, Department of Endocrinology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - R Bouillon
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, Leuven, KU, Belgium
| | - B Dawson-Hughes
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - P R Ebeling
- Department of Medicine, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
| | - D Feldman
- Department of Medicine, Endocrinology Division, Stanford University School of Medicine, Stanford, CA, USA
| | - A M Formenti
- Chair of Endocrinology, School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Endocrinology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - M Lazaretti-Castro
- Division of Endocrinology, Escola Paulista de Medicina - Universidade Federal de Sao Paulo (EPM-UNIFESP), Sao Paulo, Brazil
| | - C Marcocci
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - R Rizzoli
- Divison of Bone Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland
| | - C T Sempos
- Vitamin D Standardization Program LLC, Havre de Grace, MD, USA
| | - J P Bilezikian
- Department of Medicine, Endocrinology Division, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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Huang Y, Ma X, Tan Y, Wang L, Wang J, Lan L, Qiu Z, Luo J, Zeng H, Shu W. Consumption of Very Low Mineral Water Is Associated with Lower Bone Mineral Content in Children. J Nutr 2019; 149:1994-2000. [PMID: 31373351 DOI: 10.1093/jn/nxz161] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/10/2019] [Accepted: 06/17/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Our previous study found that consumption of very low mineral drinking water may retard height development in schoolchildren; however, its association with bone modeling remained unknown. OBJECTIVES The aim of this study was to investigate the influence of very low mineral water on biomarkers of bone modeling in children. METHODS A retrospective cohort study was conducted among 2 groups of 10-13-y-old children who had consumed drinking water with normal mineral contents (conductivity 345 μs/cm, the NW group including 119 boys and 110 girls) or very low mineral contents (conductivity 40.0 μs/cm, the VLW group including 223 boys and 208 girls) in school for 4 y. Differences in daily total mineral intakes, developmental parameters, serum biomarkers of osteoblast activity, and bone formation and resorption between the 2 groups were analyzed with independent t test and chi-square test. Associations of developmental parameters and serum biomarkers with Ca intake from drinking water were analyzed with multiple linear regression and binary logistic regression. RESULTS Compared with the NW group, the VLW group had lower daily Ca intake, height increase, bone mineral content (BMC), osteoblast activity [serum bone alkaline phosphatase (BALP)] (means ± SDs: 433 ± 131 mg, 16.6 ± 8.27 cm, 1.92 ± 0.431 kg, and 9.28 ± 1.42 μg/L compared with 497 ± 155 mg, 22.3 ± 8.45 cm, 2.14 ± 0.354 kg, and 11.0 ± 0.823 μg/L, respectively, P < 0.001), and higher bone resorption [serum crosslinked C-telopeptide of type I collagen (CTX), mean ± SD: 142 ± 46.9 nmol/L compared with 130 ± 40.6 nmol/L, P = 0.001). Ca intake from drinking water was positively associated with height increase, BMC, and BALP (β: 0.0667, 95% CI: 0.0540, 0.0793; β: 3.22, 95% CI: 2.37, 4.08; and β: 23.9, 95% CI: 20.6, 27.2), respectively, P < 0.001), and was negatively associated with CTX (β: -0.206, 95% CI:-0.321, -0.0904, P < 0.001). CONCLUSIONS These changes suggested that consumption of very low mineral water may be associated with osteoblast inhibition, bone resorption activation, bone mineral reduction, and height development retardation. The health risk of consuming very low mineral water should be considered in children.
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Affiliation(s)
- Yujing Huang
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiangyu Ma
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yao Tan
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lingqiao Wang
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jia Wang
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lan Lan
- Health Supervision Institute of Nan'an, Health and Family Planning Commission of Nan'an, Chongqing, China
| | - Zhiqun Qiu
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jiaohua Luo
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Hui Zeng
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Weiqun Shu
- Department of Environmental Hygiene, College of Preventive Medicine, Army Medical University (Third Military Medical University), Chongqing, China
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Abstract
Severe vitamin D deficiency can be defined as the dose of vitamin D or serum 25OHD concentrations needed to prevent nutritional rickets or osteomalacia. There is large international consensus that these diseases can be prevented by 400 IU of vitamin D/d and 25OHD above 30 nmol/l (12 ng/ml). Vitamin D deficiency can also accelerate the risk of fractures and probably also of falls in elderly subjects but there is no consensus on the required daily doses or minimal 25OHD threshold for these endpoints. The majority of experts consider 800 IU/d and serum 25OHD above 50 nmol/l (20 ng/ml) as sufficient, with a minority opinion aiming for 75 nmol/l or even higher. For other extra-skeletal endpoints, no hard evidence is available to define whether or not this is causally related to vitamin D status. Therefore, for these endpoints no minimal dosage or 25OHD threshold can be defined.
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Affiliation(s)
- Roger Bouillon
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Belgium.
| | - Geert Carmeliet
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Belgium
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Lee SM, Meyer MB, Benkusky NA, O'Brien CA, Pike JW. The impact of VDR expression and regulation in vivo. J Steroid Biochem Mol Biol 2018; 177:36-45. [PMID: 28602960 PMCID: PMC5723236 DOI: 10.1016/j.jsbmb.2017.06.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/02/2017] [Accepted: 06/05/2017] [Indexed: 12/23/2022]
Abstract
The vitamin D receptor (VDR) mediates the pleiotropic biological actions of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). These actions include orchestration of mineral homeostasis which is coordinated by the kidney, intestine, bone and parathyroid gland wherein the VDR transcriptionally regulates expression of the genes involved in this complex process. Mutations in human VDR (hVDR) cause hereditary vitamin D resistant rickets, a genetic syndrome characterized by hypocalcemia, hyperparathyroidism and rickets resulting from dysregulation of mineral homeostasis. Expression of the VDR is regulated by external stimuli in a tissue-specific manner. However, the mechanisms of this tissue-specificity remain unclear. Studies also suggest that phosphorylation of hVDR at serine 208 impacts the receptor's transcriptional activity. These experiments were conducted in vitro, however, and therefore limited in their conclusions. In this report, we summarize (1) our most recently updated ChIP-seq data from mouse tissues to identify regulatory regions responsible for the tissues-specific regulation of the VDR and (2) our studies to understand the mechanism of hormonal regulation of Vdr expression in bone and kidney in vivo using transgenic mouse strains generated by mouse mini-genes that contain comprehensive genetic information capable of recapitulating endogenous Vdr gene regulation and expression. We also defined the functional human VDR gene locus in vivo by using a human mini-gene comparable to that in the mouse to generate a humanized VDR mouse strain in which the receptor is expressed at normal levels (normal expressor). The present report also shows that a humanized mouse model in which the VDR is expressed at levels about 10-fold lower than the normal expressor mouse rescued the VDR-null phenotype despite its reduced transcriptional activity relative to wildtype expression. We also generated an additional humanized mouse model expressing hVDR bearing a mutation converting serine 208 to alanine (hVDR-S208A). In spite of the mutation, target gene expression induced by the ligand was unchanged relative to a mouse strain expressing comparable levels of wildtype hVDR. Further characterization also showed that serum calcium and parathyroid hormone levels were normal and alopecia was not observed in this hVDR-S208A mouse strain as well. Taken together, our in vivo studies using ChIP-seq analyses and the mini-gene transgenic mice improve our understanding of the tissue-specific regulatory mechanisms of controlling VDR expression and the mechanisms of action of the VDR.
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Affiliation(s)
- Seong Min Lee
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Mark B Meyer
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Nancy A Benkusky
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Charles A O'Brien
- University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - J Wesley Pike
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States.
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Uekawa A, Yamanaka H, Lieben L, Kimira Y, Uehara M, Yamamoto Y, Kato S, Ito K, Carmeliet G, Masuyama R. Phosphate-dependent luminal ATP metabolism regulates transcellular calcium transport in intestinal epithelial cells. FASEB J 2018; 32:1903-1915. [PMID: 29282249 DOI: 10.1096/fj.201700631r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Extracellular low phosphate strongly enhances intestinal calcium absorption independently of active vitamin D [1,25(OH)2D3] signaling, but the underlying mechanisms remain poorly characterized. To elucidate the phosphate-dependent regulation of calcium transport, we investigated part of the enteral environment that is involved in 1,25(OH)2D3-independent calcium absorption, which responds to dietary phosphate levels in mice that lack intestinal vitamin D receptor ( Vdr) activity. Impaired calcium absorption in intestinal Vdr-null mice was improved by dietary phosphate restriction. Accordingly, calcium transport in cultured intestinal epithelial cells was increased when the apical side was exposed to low phosphate levels (0.5 mM) compared with normal or high phosphate levels (1.0 or 5.0 mM, respectively). Mechanistically, low phosphate increased ATP in the apical side medium and allowed calcium entry into epithelial cells via the P2X7 purinoreceptor, which results in increased calcium transport. We found that luminal ATP was regulated by the release and degradation of ATP at the epithelium, and phosphate restriction increased ATP release from epithelial cells via connexin-43 hemichannels. Furthermore, ATP degradation by ectonucleotide pyrophosphatase-1 was reduced, which was caused by the reduction of the MAPK cascade. These findings indicate that luminal ATP metabolism regulates transcellular calcium transport in the intestine by an 1,25(OH)2D3-independent mechanism in response to dietary phosphate levels.-Uekawa, A., Yamanaka, H., Lieben, L., Kimira, Y., Uehara, M., Yamamoto, Y., Kato, S., Ito, K., Carmeliet, G., Masuyama, R. Phosphate-dependent luminal ATP metabolism regulates transcellular calcium transport in intestinal epithelial cells.
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Affiliation(s)
- Atsushi Uekawa
- Department of Molecular Bone Biology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Hitoki Yamanaka
- Center for Frontier Life Sciences, Nagasaki University, Nagasaki, Japan
| | - Liesbet Lieben
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | - Yoshifumi Kimira
- Department of Nutritional Science, Tokyo University of Agriculture, Tokyo, Japan
| | - Mariko Uehara
- Department of Nutritional Science, Tokyo University of Agriculture, Tokyo, Japan
| | - Yoko Yamamoto
- Surgical Oncology and Vascular Surgery, University of Tokyo, Tokyo, Japan
| | - Shigeaki Kato
- Research Institute of Innovative Medicine, Tokiwa Foundation, Iwaki, Fukushima, Japan
| | - Kosei Ito
- Department of Molecular Bone Biology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Geert Carmeliet
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | - Ritsuko Masuyama
- Department of Molecular Bone Biology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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Dhawan P, Veldurthy V, Yehia G, Hsaio C, Porta A, Kim KI, Patel N, Lieben L, Verlinden L, Carmeliet G, Christakos S. Transgenic Expression of the Vitamin D Receptor Restricted to the Ileum, Cecum, and Colon of Vitamin D Receptor Knockout Mice Rescues Vitamin D Receptor-Dependent Rickets. Endocrinology 2017; 158:3792-3804. [PMID: 28938396 PMCID: PMC5695835 DOI: 10.1210/en.2017-00258] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 09/06/2017] [Indexed: 01/01/2023]
Abstract
Although the intestine plays the major role in 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] action on calcium homeostasis, the mechanisms involved remain incompletely understood. The established model of 1,25(OH)2D3-regulated intestinal calcium absorption postulates a critical role for the duodenum. However, the distal intestine is where 70% to 80% of ingested calcium is absorbed. To test directly the role of 1,25(OH)2D3 and the vitamin D receptor (VDR) in the distal intestine, three independent knockout (KO)/transgenic (TG) lines expressing VDR exclusively in the ileum, cecum, and colon were generated by breeding VDR KO mice with TG mice expressing human VDR (hVDR) under the control of the 9.5-kb caudal type homeobox 2 promoter. Mice from one TG line (KO/TG3) showed low VDR expression in the distal intestine (<50% of the levels observed in KO/TG1, KO/TG2, and wild-type mice). In the KO/TG mice, hVDR was not expressed in the duodenum, jejunum, kidney, or other tissues. Growth arrest, elevated parathyroid hormone level, and hypocalcemia of the VDR KO mice were prevented in mice from KO/TG lines 1 and 2. Microcomputed tomography analysis revealed that the expression of hVDR in the distal intestine of KO/TG1 and KO/TG2 mice rescued the bone defects associated with systemic VDR deficiency, including growth plate abnormalities and altered trabecular and cortical parameters. KO/TG3 mice showed rickets, but less severely than VDR KO mice. These findings show that expression of VDR exclusively in the distal intestine can prevent abnormalities in calcium homeostasis and bone mineralization associated with systemic VDR deficiency.
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Affiliation(s)
- Puneet Dhawan
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Vaishali Veldurthy
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Ghassan Yehia
- The Genome Editing Core Facility, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Connie Hsaio
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Angela Porta
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Ki-in Kim
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Nishant Patel
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Liesbet Lieben
- Clinical and Experimental Medicine and Endocrinology, KU Leuven, Leuven B-3000, Belgium
| | - Lieve Verlinden
- Clinical and Experimental Medicine and Endocrinology, KU Leuven, Leuven B-3000, Belgium
| | - Geert Carmeliet
- Clinical and Experimental Medicine and Endocrinology, KU Leuven, Leuven B-3000, Belgium
| | - Sylvia Christakos
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
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Fleet JC. The role of vitamin D in the endocrinology controlling calcium homeostasis. Mol Cell Endocrinol 2017; 453:36-45. [PMID: 28400273 PMCID: PMC5529228 DOI: 10.1016/j.mce.2017.04.008] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/07/2017] [Accepted: 04/08/2017] [Indexed: 12/14/2022]
Abstract
Vitamin D and its' metabolites are a crucial part of the endocrine system that controls whole body calcium homeostasis. The goal of this hormonal control is to regulate serum calcium levels so that they are maintained within a very narrow range. To achieve this goal, regulatory events occur in coordination at multiple tissues, e.g. the intestine, kidney, bone, and parathyroid gland. Production of the vitamin D endocrine hormone, 1,25 dihydroxyvitamin D (1,25(OH)2 D) is regulated by habitual dietary calcium intake and physiologic states like growth, aging, and the menopause. The molecular actions of 1,25(OH)2 D on calcium regulating target tissues are mediated predominantly by transcription controlled by the vitamin D receptor. A primary role for 1,25(OH)2 D during growth is to increase intestinal calcium absorption so that sufficient calcium is available for bone mineralization. However, vitamin D also has specific actions on kidney and bone.
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Affiliation(s)
- James C Fleet
- Department of Nutrition Science, Room G1B Stone Hall, Purdue University, West Lafayette, IN 47907-2059, United States.
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