CYP27B1
25-hydroxyvitamin D-1 alpha hydroxylase, mitochondrial precursor (EC 1.14.15.18) (25-OHD-1 alpha-hydroxylase) (25-hydroxyvitamin D(3) 1-alpha-hydroxylase) (VD3 1A hydroxylase) (Calcidiol 1-monooxygenase) (Cytochrome P450 subfamily XXVIIB polypeptide 1) (Cytochrome P450C1 alpha) (Cytochrome P450VD1-alpha) (Cytochrome p450 27B1) [CYP1ALPHA] [CYP27B]
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To clarify the regulation of astragalus on the aging BMSCs model and the effect of astragalus on Vitamin D (VD)-FGF23-Klotho axis. siRNA was used to interfere the expression of VDR gene in aging BMSCs. Serum containing astragalus in different concentrations was added to the cultured cells. The expression of osteocalcin and alkaline phosphatase were detected by alizarin red staining and ELISA. Cell vitality was detected by flow cytometry, CCK-8 test, and [i]β[/i]-galactosidase staining. The expression of FGF23, Klotho, CYP27B1, and CYP24A1 was detected by qRT-PCR and western blot. The results showed that after reducing VDR gene expression, the aging BMSCs model showed decreased activity and osteogenic ability, increased expression of FGF23, Klotho and CYP24A1, and decreased expression of CYP27B1. After adding serum-containing astragalus, the activity of cells and the osteogenic ability was increased; the expression levels of FGF23, Klotho and CYP24A1 were decreased, the expression levels of CYP27B1 were increased, and the trend was more obvious with the increase of astragalus concentration. This study confirmed that astragalus could inhibit the aging of BMSCs and improve the osteogenesis ability by regulating the VD-FGF23-Klotho pathway. This study provided a certain research basis for the therapeutic of traditional Chinese medicine (TCM) on primary osteoporosis.
Keywords
- Astragalus
- BMSCs
- VD-FGF23-Klotho axis
- aging
- osteogenesis differentiation
The prevalence of vitamin D deficiency, as determined by circulating levels of 25-hydroxycalciferol [25(OH)D], is greater in older individuals compared with the young. To examine the hypothesis that altered production or inactivation of 25(OH)D contributes to lower circulating levels of 25(OH)D, we measured the serum levels of parent vitamin D3 (cholecalciferol) and 25(OH)D. We also determined the relative abundance of transcripts encoding hepatic CYP2R1 and CYP27B1, the principal 25-hydroxylases, transcripts encoding enzymes that degrade 25(OH)D in the liver (Cyp3A11) and kidney (Cyp24A1) and transcripts encoding megalin and cubilin, proteins critical to vitamin D resorption in the kidney in mice at three different ages. We observed a significant decline in the relative abundance of Cyp2R1 in the liver with aging (one-way ANOVA, P = 0.0077). Concurrent with the decrease in mRNA, a significant decline in hepatic CYP2R1 protein (one-way ANOVA for trend, P = 0.007) and 25(OH)D (one-way ANOVA for trend, P = 0.002) and in the ratio of 25(OH)D3 to cholecalciferol (one-way ANOVA, P = 0.0003). By contrast, levels of the transcripts encoding Cyp3a11, Cyp24a1, and Cyp27b1 megalin and cubilin were unchanged with aging. A significant positive correlation was found between Cyp2r1 mRNA and 25(OH)D, and a stronger correlation was found between Cyp2r1 mRNA and the ratio of 25(OH)D3 to cholecalciferol. These results indicate that decreased expression of CYP2R1 contributes to the reduced serum levels of 25(OH)D in aging.
MeSH Terms
- Aging
- Animals
- Cholecalciferol
- Cholestanetriol 26-Monooxygenase
- Cytochrome P-450 CYP3A
- Gene Expression
- Kidney
- Liver
- Low Density Lipoprotein Receptor-Related Protein-2
- Male
- Membrane Proteins
- Mice
- RNA, Messenger
- Receptors, Cell Surface
- Vitamin D
- Vitamin D Deficiency
- Vitamin D3 24-Hydroxylase
Oleanolic acid (OA) is a triterpenoid with reported bone anti-resorption activities. The present study aimed to characterize its bone protective effects in vivo and to study its effects on vitamin D metabolism, both in vivo and in vitro. OA significantly increased bone mineral density, improved micro-architectural properties, reduced urinary Ca excretion, increased 1,25(OH)₂D₃ and renal CYP27B1 mRNA expression in mature C57BL/6 ovariectomised (OVX) mice. OA also improved bone properties, Ca balance, and exerted modulatory effects on renal CYP27B1 and CYP24A1 expressions in aged normal female Sprague-Dawley rats. In addition, OA significantly increased renal CYP27B1 mRNA and promoter activity, and suppressed CYP24A1 mRNA and protein expressions in human proximal tubule HKC-8 cells. OA exerted bone protective effects in mature OVX mice and aged female rats. This action on bone might be, at least in part, associated with its effects on Ca and vitamin D metabolism. The present findings suggest that OA is a potential drug candidate for the management of postmenopausal osteoporosis.
MeSH Terms
- 25-Hydroxyvitamin D3 1-alpha-Hydroxylase
- Animals
- Bone Density
- Bone Density Conservation Agents
- Bone Remodeling
- Bone and Bones
- Calcitriol
- Calcium
- Cell Line
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Duodenum
- Female
- Humans
- Kidney Tubules, Proximal
- Mice, Inbred C57BL
- Oleanolic Acid
- Osteoporosis, Postmenopausal
- Ovariectomy
- Rats, Sprague-Dawley
- Vitamin D
- Vitamin D3 24-Hydroxylase
- X-Ray Microtomography
Keywords
- aging
- calcium
- oleanolic acid
- osteoporosis
- ovariectomised
- vitamin D
Despite the high prevalence of vitamin D deficiency among older adults in the UK, studies investigating the determinants of vitamin D status in this group are lacking. We conducted a cross-sectional study in 222 older adults living in sheltered accommodation in London, UK, who were screened for participation in a clinical trial of vitamin D supplementation for the prevention of acute respiratory infection. Details of potential demographic and lifestyle determinants of vitamin D status were collected by questionnaire and blood samples were taken for analysis of serum 25-hydroxyvitamin D (25[OH]D) concentration and DNA extraction. Fifteen single nucleotide polymorphisms (SNP) in 6 genes (DBP, DHCR7, CYP2R1, CYP27B1, CYP24A1, VDR) previously reported to associate with circulating 25(OH)D concentration were typed using Taqman allelic discrimination assays. Linear regression was used to identify environmental and genetic factors independently associated with serum 25(OH)D concentration. Mean serum 25(OH)D concentration was 42.7nmol/L (SD 22.0); 144/222 (64.9%) participants had serum 25(OH)D concentrations <50nmol/L. The following factors were independently associated with lower serum 25(OH)D concentration: non-white ethnicity (-8.6nmol/L, 95% CI -14.9 to -2.3, P=0.008); lack of vitamin D supplement consumption (-17.1nmol/L, 95% CI -23.3 to -10.9, P<0.001) vs. taking a daily supplement; sampling in Q1/January-March (-12.2nmol/L, 95% CI -21.5 to -2.9, P=0.01), and sampling in Q4/October-December (-10.3nmol/L, 95% CI -20.2 to -0.4, P=0.04) vs. sampling in Q3/July-September. None of the 15 SNP investigated independently associated with serum 25(OH)D concentration after correcting for multiple comparisons. In conclusion, vitamin D deficiency was highly prevalent among the older adults in this study; non-White ethnicity, lack of vitamin D supplement consumption and sampling in winter and spring independently associated with lower vitamin D status.
MeSH Terms
- 25-Hydroxyvitamin D3 1-alpha-Hydroxylase
- Aged
- Aged, 80 and over
- Aging
- Cholestanetriol 26-Monooxygenase
- Clinical Trials as Topic
- Cohort Studies
- Cross-Sectional Studies
- Cytochrome P450 Family 2
- DNA-Binding Proteins
- Diet
- Dietary Supplements
- Female
- Genetic Predisposition to Disease
- Humans
- London
- Male
- Middle Aged
- Oxidoreductases Acting on CH-CH Group Donors
- Polymorphism, Single Nucleotide
- Receptors, Calcitriol
- Seasons
- Transcription Factors
- Vitamin D
- Vitamin D Deficiency
- Vitamin D3 24-Hydroxylase
Keywords
- Ageing
- Diet
- Polymorphism
- Season
- Single nucleotide
- Vitamin D
With aging, there is a decline in bone mass and in osteoblast differentiation of human mesenchymal stem cells (hMSCs) in vitro. Osteoblastogenesis can be stimulated with 1,25-dihydroxyvitamin D(3) [1,25(OH)(2) D(3) ] and, in some hMSCs, by the precursor 25-hydroxyvitamin D(3) (25OHD(3) ). CYP27B1/1α-hydroxylase activates 25OHD(3) and, to a variable degree, hMSCs express CYP27B1. In this study, we tested the hypotheses (i) that age affects responsiveness to 25OHD(3) and expression/activity of CYP27B1 in hMSCs and (ii) that parathyroid hormone (PTH) upregulates CYP27B1 in hMSCs, as it does in renal cells. There were age-related declines in osteoblastogenesis (n=8, P=0.0286) and in CYP27B1 gene expression (n=27, r= -0.498; P=0.008) in hMSCs. Unlike hMSCs from young subjects (≤50 years), hMSCs from older subjects (≥55 years) were resistant to 25OHD(3) stimulation of osteoblastogenesis. PTH1-34 (100 nm) provided hMSCs with responsiveness to 25OHD(3) (P=0.0313, Wilcoxon matched pairs test) and with two episodes of increased 1,25(OH)(2) D(3) synthesis, of cAMP response element binding protein (CREB) activation, and of CYP27B1 upregulation. Both increases in CYP27B1 expression by PTH were obliterated by CREB-siRNA or KG-501 (which specifically inhibits the downstream binding of activated CREB). Only the second period of CREB signaling was diminished by AG1024, an inhibitor of insulin-like growth factor-I receptor kinase. Thus, PTH stimulated hMSCs from elders with responsiveness to 25OHD(3) by upregulating expression/activity of CYP27B1 and did so through CREB and IGF-I pathways.
MeSH Terms
- 25-Hydroxyvitamin D3 1-alpha-Hydroxylase
- Adult
- Aged
- Aging
- Blotting, Western
- Calcifediol
- Cell Differentiation
- Cyclic AMP Response Element-Binding Protein
- Enzyme Inhibitors
- Gene Expression Regulation, Enzymologic
- Humans
- Insulin-Like Growth Factor I
- Mesenchymal Stem Cells
- Naphthols
- Organophosphates
- Osteoblasts
- Parathyroid Hormone
- Polymerase Chain Reaction
- RNA, Small Interfering
- Signal Transduction
- Steroid Hydroxylases
- Tyrphostins
- Vitamin D
The nuclear vitamin D receptor (VDR) binds 1,25-dihydroxyvitamin D3 (1,25D), its high affinity renal endocrine ligand, to signal intestinal calcium and phosphate absorption plus bone remodeling, generating a mineralized skeleton free of rickets/osteomalacia with a reduced risk of osteoporotic fractures. 1,25D/VDR signaling regulates the expression of TRPV6, BGP, SPP1, LRP5, RANKL and OPG, while achieving feedback control of mineral ions to prevent age-related ectopic calcification by governing CYP24A1, PTH, FGF23, PHEX, and klotho transcription. Vitamin D also elicits numerous intracrine actions when circulating 25-hydroxyvitamin D3, the metabolite reflecting vitamin D status, is converted to 1,25D locally by extrarenal CYP27B1, and binds VDR to promote immunoregulation, antimicrobial defense, xenobiotic detoxification, anti-inflammatory/anticancer actions and cardiovascular benefits. VDR also affects Wnt signaling through direct interaction with beta-catenin, ligand-dependently blunting beta-catenin mediated transcription in colon cancer cells to attenuate growth, while potentiating beta-catenin signaling via VDR ligand-independent mechanisms in osteoblasts and keratinocytes to function osteogenically and as a pro-hair cycling receptor, respectively. Finally, VDR also drives the mammalian hair cycle in conjunction with the hairless corepressor by repressing SOSTDC1, S100A8/S100A9, and PTHrP. Hair provides a shield against UV-induced skin damage and cancer in terrestrial mammals, illuminating another function of VDR that facilitates healthful aging.
MeSH Terms
- Aging
- Animals
- Calcium
- Cell Nucleus
- Gene Expression Regulation
- Humans
- Keratinocytes
- Mice
- Models, Biological
- Osteopontin
- Phosphates
- Receptors, Calcitriol
- Signal Transduction
- Wnt Proteins
- beta Catenin
Recent studies using genetically modified mice, such as FGF23-/- and Klotho-/- mice that exhibit altered mineral homeostasis due to a high vitamin D activity showed features of premature aging that include retarded growth, osteoporosis, atherosclerosis, ectopic calcification, immunological deficiency, skin and general organ atrophy, hypogonadism and short lifespan. The phenotype reversed by normalizing vitamin D and/or mineral homeostasis. Thus, hypervitaminosis D due to an increased 1alpha-hydroxylase activity seems to be a cause of the premature aging. In several studies, we have described that a complete or partial lack of vitamin D action (VDR-/- mice and CYP27B1-/-) show almost similar phenotype as FGF23-/- or Klotho-/- mice. VDR mutant mice have growth retardation, osteoporosis, kyphosis, skin thickening and wrinkling, alopecia, ectopic calcification, progressive loss of hearing and balance as well as short lifespan. CYP27B1-/- mice do not show alopecia nor balance deficit, which might be apoVDR-dependent or calcidiol-dependent. The features are typical to premature aging. The phenotype is resistant to a normalization of the mineral homeostasis by a rescue diet containing high calcium and phosphate. Taken together, aging shows a U-shaped dependency on hormonal forms of vitamin D suggesting that there is an optimal concentration of vitamin D in delaying aging phenomena. Our recent study shows that calcidiol is an active hormone. Since serum calcidiol but not calcitriol is fluctuating in physiological situations, calcidiol might determine the biological output of vitamin D action. Due to its high serum concentration and better uptake of calcidiol-DBP by the target cells through the cubilin-megalin system, calcidiol seems to be an important circulating hormone. Therefore, serum calcidiol might be associated with an increased risk of aging-related chronic diseases more directly than calcitriol. Aging and cancer seem to be tightly associated phenomena. Accumulation of damage on DNA and telomeres cause both aging and cancer, moreover the signalling pathways seem to converge on tumour suppressor protein, p53, which seems to be regulated by vitamin D. Also, the insulin-like growth factor signalling pathway (IGF-1, IGFBPs, IGFR) and fibroblast growth factor-23 (FGF-23) regulate growth, aging and cancer. Vitamin D can regulate these signalling pathways, too. Also NF-kappaB and telomerase reverse transcriptase (TERT) might be molecular mechanisms mediating vitamin D action in aging and cancer. Calcidiol serum concentrations show a U-shaped risk of prostate cancer suggesting an optimal serum concentration of 40-60 nmol/L for the lowest cancer risk. Therefore, it is necessary to study several common aging-associated diseases such as osteoporosis, hypertension and diabetes known to be vitamin D-dependent before any recommendations of an optimal serum concentration of calcidiol are given.
MeSH Terms
- Aging
- Aging, Premature
- Animals
- Calcifediol
- Calcitriol
- Fibroblast Growth Factors
- Glucuronidase
- Humans
- Neoplasms
- Nutrition Disorders
- Vitamin D
- Vitamin D Deficiency
Mice lacking 25-hydroxycholecalciferol [25(OH)D]-1alpha-hydroxylase (CYP27B1) are growth retarded, hypocalcemic, and have poor bone mineralization. We tested whether high dietary cholecalciferol (VD3) could exert effects in the absence of CYP27B1 in vivo. Weanling male wild-type (WT) and CYP27B1 knockout (KO) mice were fed either a 2% calcium (Ca), 20% lactose rescue diet or an AIN93G diet (0.5% Ca, 0.4% phosphorus) containing 1000 (1K, the rodent requirement, 25 microg), 10,000 (10K, 250 microg), or 20,000 (20K, 500 microg) IU VD3/kg diet until 12 wk when blood and tissues were taken. Serum 25(OH)D was >90 nmol/L in the 1K diet group and increased >4-fold in mice fed 10K and 20K diets. The 1K diet impaired growth and caused hypocalcemia in KO mice; the 10K and 20K diets were as effective as the high Ca rescue diet in preventing these outcomes. High VD3 restored expression of vitamin D-regulated genes in intestine (calbindin D(9K)) and kidney (CYP27B1, 24-hydroxylase, calbindin D(9K)) of KO mice. Micro-computed tomography of femora revealed complete recovery of cortical bone in KO mice fed either the rescue or 10K diets but only partial recovery of trabecular bone measures (e.g. 40% lower bone volume, 20% lower trabecular thickness, and 23% increase in trabecular separation). These data show that very high serum 25(OH)D can influence Ca and bone metabolism independent of its conversion to 1,25 dihydroxycholecalciferol. However, neither high dietary Ca nor high dietary VD3 is sufficient to fully recover the phenotype of CYP27B1 KO mice.
MeSH Terms
- 25-Hydroxyvitamin D3 1-alpha-Hydroxylase
- Aging
- Animals
- Calcium, Dietary
- Diet
- Genetic Predisposition to Disease
- Hypocalcemia
- Mice
- Mice, Knockout
- Osteomalacia
- Vitamin D