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Gleba JJ, Kłopotowska D, Banach J, Mielko KA, Turlej E, Maciejewska M, Kutner A, Wietrzyk J. Micro-RNAs in Response to Active Forms of Vitamin D3 in Human Leukemia and Lymphoma Cells. Int J Mol Sci 2022; 23:ijms23095019. [PMID: 35563410 PMCID: PMC9104187 DOI: 10.3390/ijms23095019] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/19/2022] [Accepted: 04/29/2022] [Indexed: 11/16/2022] Open
Abstract
Non-coding micro-RNA (miRNAs) regulate the protein expression responsible for cell growth and proliferation. miRNAs also play a role in a cancer cells’ response to drug treatment. Knowing that leukemia and lymphoma cells show different responses to active forms of vitamin D3, we decided to investigate the role of selected miRNA molecules and regulated proteins, analyzing if there is a correlation between the selected miRNAs and regulated proteins in response to two active forms of vitamin D3, calcitriol and tacalcitol. A total of nine human cell lines were analyzed: five leukemias: MV-4-1, Thp-1, HL-60, K562, and KG-1; and four lymphomas: Raji, Daudi, Jurkat, and U2932. We selected five miRNA molecules—miR-27b, miR-32, miR-125b, miR-181a, and miR-181b—and the proteins regulated by these molecules, namely, CYP24A1, Bak1, Bim, p21, p27, p53, and NF-kB. The results showed that the level of selected miRNAs correlates with the level of proteins, especially p27, Bak1, NFκB, and CYP24A1, and miR-27b and miR-125b could be responsible for the anticancer activity of active forms of vitamin D3 in human leukemia and lymphoma.
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Affiliation(s)
- Justyna Joanna Gleba
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland; (D.K.); (J.B.); (K.A.M.); (E.T.); (M.M.); (J.W.)
- Correspondence: ; Tel.: +48-1-904-207-2571
| | - Dagmara Kłopotowska
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland; (D.K.); (J.B.); (K.A.M.); (E.T.); (M.M.); (J.W.)
| | - Joanna Banach
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland; (D.K.); (J.B.); (K.A.M.); (E.T.); (M.M.); (J.W.)
| | - Karolina Anna Mielko
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland; (D.K.); (J.B.); (K.A.M.); (E.T.); (M.M.); (J.W.)
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Norwida 4/6, 50-373 Wroclaw, Poland
| | - Eliza Turlej
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland; (D.K.); (J.B.); (K.A.M.); (E.T.); (M.M.); (J.W.)
- Department of Experimental Biology, The Wroclaw University of Environmental and Life Sciences, Norwida 27 B, 50-375 Wroclaw, Poland
| | - Magdalena Maciejewska
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland; (D.K.); (J.B.); (K.A.M.); (E.T.); (M.M.); (J.W.)
| | - Andrzej Kutner
- Department of Bioanalysis and Drug Analysis, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha, 02-097 Warsaw, Poland;
| | - Joanna Wietrzyk
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland; (D.K.); (J.B.); (K.A.M.); (E.T.); (M.M.); (J.W.)
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Abd El-Haleim EA, Sallam NA. Vitamin D modulates hepatic microRNAs and mitigates tamoxifen-induced steatohepatitis in female rats. Fundam Clin Pharmacol 2021; 36:338-349. [PMID: 34312906 DOI: 10.1111/fcp.12720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 07/23/2021] [Indexed: 12/26/2022]
Abstract
Tamoxifen (TAM) is a life-saving and cost-effective drug widely used in the prevention and treatment of breast cancer. However, the adverse effects of tamoxifen can lead to non-adherence and poor patient outcomes. Therefore, exploring novel strategies to improve TAM safety profile is crucial. Given the key role that vitamin D (VD) plays in modulating lipid metabolism and inflammation, in addition to its benefits in reducing risk and progression of breast cancer, we evaluated the protective potential of VD against TAM-induced hepatotoxicity focusing on lipid metabolism and microRNAs (miRNAs) regulation. Female rats were pretreated with VD as cholecalciferol (500 IU/kg/day, po) for 4 weeks before receiving TAM (40 mg/kg/day, po) concurrently with VD during the fifth and sixth weeks. Liver histology, lipid profile and expression of genes, proteins, and miRNAs involved in lipid metabolism and inflammation were examined. TAM-induced steatohepatitis was evidenced by elevated liver triglycerides and cholesterol contents, increased serum miRNA-122 level, and ALT activity, in parallel with accumulation of lipid droplets, focal necrosis, and inflammatory cells infiltration in hepatocytes. Prophylactic use of VD mitigated TAM-induced steatohepatitis by modulating key transcription factors in the liver: PPAR-α, Srebf1, and NF-κB and their downstream genes/proteins Fas, CPT-1A, and TNF-α resulting in reduced hepatic lipids and suppressed pro-inflammatory signaling. Notably, VD pretreatment mitigated TAM-induced alterations in the expression of serum miRNA-122, hepatic miRNA-21, and miRNA-33. The combination therapy of VD and TAM has complementary benefits in terms of safety and not only efficacy and should be further investigated clinically.
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Affiliation(s)
- Enas A Abd El-Haleim
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Nada A Sallam
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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Zand L, Kumar R. The Use of Vitamin D Metabolites and Analogues in the Treatment of Chronic Kidney Disease. Endocrinol Metab Clin North Am 2017; 46:983-1007. [PMID: 29080646 PMCID: PMC5977979 DOI: 10.1016/j.ecl.2017.07.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are associated with abnormalities in bone and mineral metabolism, known as CKD-bone mineral disorder. CKD and ESRD cause skeletal abnormalities characterized by hyperparathyroidism, mixed uremic osteodystrophy, osteomalacia, adynamic bone disease, and frequently enhanced vascular and ectopic calcification. Hyperparathyroidism and mixed uremic osteodystrophy are the most common manifestations due to phosphate retention, reduced concentrations of 1,25-dihydroxyvitamin D, intestinal calcium absorption, and negative calcium balance. Treatment with 1-hydroxylated vitamin D analogues is useful.
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Affiliation(s)
- Ladan Zand
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55901, USA.
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55901, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN 55901, USA.
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Nunez Lopez YO, Pittas AG, Pratley RE, Seyhan AA. Circulating levels of miR-7, miR-152 and miR-192 respond to vitamin D supplementation in adults with prediabetes and correlate with improvements in glycemic control. J Nutr Biochem 2017; 49:117-122. [PMID: 28945992 DOI: 10.1016/j.jnutbio.2017.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 07/16/2017] [Accepted: 08/17/2017] [Indexed: 02/07/2023]
Abstract
Vitamin D may play an important role in modifying the risk of type 2 diabetes. Supplementation with cholecalciferol has been shown to improve β cell function and to attenuate the rise in glycated hemoglobin in people at high risk of diabetes. We examined whether circulating microRNAs (miRNAs) reflect disease progression and/or respond to vitamin D supplementation. We measured plasma levels of select miRNAs implicated in diabetes in people with prediabetes treated either with placebo (n=21) or 2000 U of cholecalciferol daily (n=21) for 4 months in the Calcium and Vitamin D for Diabetes Mellitus trial and compared the baseline-adjusted changes after correcting for age, body mass index, race, time of study entry (season) and baseline disposition index. Circulating levels of miR-7 (sixfold reduction, P=.01), miR-152 (1.5-fold increase, P=.03), and miR-192 (1.7-fold reduction, P=.026) displayed significant treatment-by-time interactions between the placebo- and the vitamin-D-treated groups. Plasma levels of miR-7 were reduced in the vitamin D and increased in the placebo group. The change in miR-152 positively correlated with the change in levels of the circulating metabolite 25-hydroxyvitamin D (r=0.33, P=.046) and negatively correlated with the change in glycated hemoglobin (r=-0.37, P=.024). The change in miR-192 positively correlated with the change in fasting glucose (r=0.41, P<.011). In conclusion, reduction of circulating miR-7 and miR-192, accompanied by elevation of miR-152, reflects a beneficial metabolic response to vitamin D treatment in people with prediabetes. These miRNAs may be useful biomarkers in diabetes prevention trials and other studies of vitamin D.
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Affiliation(s)
- Yury O Nunez Lopez
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, 301 East Princeton Street, Orlando, FL 32804, USA
| | - Anastassios G Pittas
- Division of Endocrinology, Diabetes, and Metabolism, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA
| | - Richard E Pratley
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, 301 East Princeton Street, Orlando, FL 32804, USA; Sanford-Burnham-Prebys Medical Discovery Institute, 6400 Sanger Rd, Orlando, FL 32827, USA
| | - Attila A Seyhan
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, 301 East Princeton Street, Orlando, FL 32804, USA; Sanford-Burnham-Prebys Medical Discovery Institute, 6400 Sanger Rd, Orlando, FL 32827, USA; Massachusetts Institute of Technology, Chemical Engineering Department Cambridge, MA 02142, USA.
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Merrigan SL, Kennedy BN. Vitamin D receptor agonists regulate ocular developmental angiogenesis and modulate expression of dre-miR-21 and VEGF. Br J Pharmacol 2017; 174:2636-2651. [PMID: 28547797 DOI: 10.1111/bph.13875] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 04/26/2017] [Accepted: 05/15/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Pathological growth of ocular vasculature networks can underpin visual impairment in neovascular age-related macular degeneration, proliferative diabetic retinopathy and retinopathy of prematurity. Our aim was to uncover novel pharmacological regulators of ocular angiogenesis by phenotype-based screening in zebrafish. EXPERIMENTAL APPROACH A bioactive chemical library of 465 drugs was screened to identify small molecule inhibitors of ocular hyaloid vasculature (HV) angiogenesis in zebrafish larvae. Selectivity was assessed by evaluation of non-ocular intersegmental vasculature development. Safety pharmacology examined visual behaviour and retinal histology in larvae. Molecular mechanisms of action were scrutinized using expression profiling of target mRNAs and miRNAs in larval eyes. KEY RESULTS Library screening identified 10 compounds which significantly inhibited HV developmental angiogenesis. The validated hit calcitriol selectively demonstrated dose-dependent attenuation of HV development. In agreement, vitamin D receptor (VDR) agonists paricalcitol, doxercalciferol, maxacalcitol, calcipotriol, seocalcitol, calcifediol and tacalcitol significantly and selectively attenuated HV development. VDR agonists induced minor ocular morphology abnormalities and affected normal visual function. Calcitriol induced a three to sevenfold increase in ocular dre-miR-21 expression. Consistently, all-trans-retinoic acid attenuated HV development and increased ocular dre-miR-21 expression. Interestingly, zebrafish ocular vegfaa and vegfab expression was significantly increased while, vegfc, flt1 and kdrl expression was unchanged by calcitriol. CONCLUSION AND IMPLICATIONS These studies identified VDR agonists as significant and selective anti-angiogenics in the developing vertebrate eye and miR21 as a key downstream regulated miRNA. These targets should be further evaluated as molecular hallmarks of, and therapeutic targets for pathological ocular neovascularization.
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Affiliation(s)
- Stephanie L Merrigan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Breandán N Kennedy
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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Zeljic K, Supic G, Magic Z. New insights into vitamin D anticancer properties: focus on miRNA modulation. Mol Genet Genomics 2017; 292:511-524. [DOI: 10.1007/s00438-017-1301-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/10/2017] [Indexed: 12/17/2022]
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Abstract
Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)2D], and impaired degradation of 1,25(OH)2D. The ingestion of excessive amounts of vitamin D3 (or vitamin D2) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)2D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)2D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)2D is impaired as a result of mutations of the 1,25(OH)2D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)2D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)2D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)2D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.
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Affiliation(s)
- Peter J Tebben
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Ravinder J Singh
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Rajiv Kumar
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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Ryan ZC, Craig TA, Folmes CD, Wang X, Lanza IR, Schaible NS, Salisbury JL, Nair KS, Terzic A, Sieck GC, Kumar R. 1α,25-Dihydroxyvitamin D3 Regulates Mitochondrial Oxygen Consumption and Dynamics in Human Skeletal Muscle Cells. J Biol Chem 2015; 291:1514-28. [PMID: 26601949 DOI: 10.1074/jbc.m115.684399] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Indexed: 12/16/2022] Open
Abstract
Muscle weakness and myopathy are observed in vitamin D deficiency and chronic renal failure, where concentrations of the active vitamin D3 metabolite, 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3), are low. To evaluate the mechanism of action of 1α,25(OH)2D3 in skeletal muscle, we examined mitochondrial oxygen consumption, dynamics, and biogenesis and changes in expression of nuclear genes encoding mitochondrial proteins in human skeletal muscle cells following treatment with 1α,25(OH)2D3. The mitochondrial oxygen consumption rate (OCR) increased in 1α,25(OH)2D3-treated cells. Vitamin D3 metabolites lacking a 1α-hydroxyl group (vitamin D3, 25-hydroxyvitamin D3, and 24R,25-dihydroxyvitamin D3) decreased or failed to increase OCR. 1α-Hydroxyvitamin D3 did not increase OCR. In 1α,25(OH)2D3-treated cells, mitochondrial volume and branching and expression of the pro-fusion protein OPA1 (optic atrophy 1) increased, whereas expression of the pro-fission proteins Fis1 (fission 1) and Drp1 (dynamin 1-like) decreased. Phosphorylated pyruvate dehydrogenase (PDH) (Ser-293) and PDH kinase 4 (PDK4) decreased in 1α,25(OH)2D3-treated cells. There was a trend to increased PDH activity in 1α,25(OH)2D3-treated cells (p = 0.09). 83 nuclear mRNAs encoding mitochondrial proteins were changed following 1α,25(OH)2D3 treatment; notably, PDK4 mRNA decreased, and PDP2 mRNA increased. MYC, MAPK13, and EPAS1 mRNAs, which encode proteins that regulate mitochondrial biogenesis, were increased following 1α,25(OH)2D3 treatment. Vitamin D receptor-dependent changes in the expression of 1947 mRNAs encoding proteins involved in muscle contraction, focal adhesion, integrin, JAK/STAT, MAPK, growth factor, and p53 signaling pathways were observed following 1α,25(OH)2D3 treatment. Five micro-RNAs were induced or repressed by 1α,25(OH)2D3. 1α,25(OH)2D3 regulates mitochondrial function, dynamics, and enzyme function, which are likely to influence muscle strength.
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Affiliation(s)
| | | | | | | | | | | | - Jeffrey L Salisbury
- Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | | | | | | | - Rajiv Kumar
- From the Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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Haque S, Kaushik K, Leonard VE, Kapoor S, Sivadas A, Joshi A, Scaria V, Sivasubbu S. Short stories on zebrafish long noncoding RNAs. Zebrafish 2015; 11:499-508. [PMID: 25110965 DOI: 10.1089/zeb.2014.0994] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The recent re-annotation of the transcriptome of human and other model organisms, using next-generation sequencing approaches, has unravelled a hitherto unknown repertoire of transcripts that do not have a potential to code for proteins. These transcripts have been largely classified into an amorphous class popularly known as long noncoding RNAs (lncRNA). This discovery of lncRNAs in human and other model systems have added a new layer to the understanding of gene regulation at the transcriptional and post-transcriptional levels. In recent years, three independent studies have discovered a number of lncRNAs expressed in different stages of zebrafish development and adult tissues using a high-throughput RNA sequencing approach, significantly adding to the repertoire of genes known in zebrafish. A subset of these transcripts also shows distinct and specific spatiotemporal patterns of gene expression, pointing to a tight regulatory control and potential functional roles in development, organogenesis, and/ or homeostasis. This review provides an overview of the lncRNAs in zebrafish and discusses how their discovery could provide new insights into understanding biology, explaining mutant phenotypes, and helping in potentially modeling disease processes.
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Affiliation(s)
- Shadabul Haque
- 1 Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology , Delhi, India
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Chun RF, Blatter E, Elliott S, Fitz-Gibbon S, Rieger S, Sagasti A, Adams JS, Hewison M. Cloning of a functional 25-hydroxyvitamin D-1α-hydroxylase in zebrafish (Danio rerio). Cell Biochem Funct 2014; 32:675-82. [PMID: 25290078 DOI: 10.1002/cbf.3071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 12/14/2022]
Abstract
Activation of precursor 25-hydroxyvitamin D3 (25D) to hormonal 1,25-dihydroxyvitamin D3 (1,25D) is a pivotal step in vitamin D physiology, catalysed by the enzyme 25-hydroxyvitamin D-1α-hydroxylase (1α-hydroxylase). To establish new models for assessing the physiological importance of the 1α-hydroxylase-25D-axis, we used Danio rerio (zebrafish) to characterize expression and biological activity of the gene for 1α-hydroxylase (cyp27b1). Treatment of day 5 zebrafish larvae with inactive 25D (5-150 nM) or active 1,25D (0.1-10 nM) induced dose responsive expression (15-95-fold) of the vitamin D-target gene cyp24a1 relative to larvae treated with vehicle, suggesting the presence of Cyp27b1 activity. A full-length zebrafish cyp27b1 cDNA was then generated using RACE and RT-PCR methods. Sequencing of the resulting clone revealed an open reading frame encoding a protein of 505 amino acids with 54% identity to human CYP27B1. Transfection of a cyp27b1 expression vector into HKC-8, a human kidney proximal tubular epithelial cell line, enhanced intracrine metabolism of 25D to 1,25D resulting in greater than twofold induction of CYP24A1 mRNA expression and a 25-fold increase in 1,25D production compared to empty vector. These data indicate that we have cloned a functional zebrafish CYP27B1, representing a phylogenetically distant branch from mammals of this key enzyme in vitamin D metabolism. Further analysis of cyp27b1 expression and activity in zebrafish may provide new perspectives on the biological importance of 25D metabolism.
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Affiliation(s)
- Rene F Chun
- Department of Orthopaedic Surgery, UCLA-Orthopaedic Hospital, Los Angeles, CA, 90095, United States
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