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en: NAD metabolism and the SLC34 family: evidence for a liver-kidney axis regulating inorganic phosphate.

en: Pflügers Archiv : European Journal of Physiology


en: Vitamin D and muscle tissues

ja: ビタミンDと筋組織

en: Clinical Calcium

ja: Clinical Calcium


en: 活性型ビタミンDは，トリプトファン水酸化酵素およびレプチン遺伝子発現を制御する

ja: 活性型ビタミンDは，トリプトファン水酸化酵素およびレプチン遺伝子発現を制御する

en: Vitamins

ja: ビタミン


en: Control of phosphate balance by the kidney and intestine.

en: The prevention and correction of hyperphosphatemia are major goals of the treatment of chronic kidney disease (CKD)-bone mineral disorders, and thus, Pi balance requires special attention. Pi balance is maintained by intestinal absorption, renal excretion, and bone accretion. The kidney is mainly responsible for the plasma Pi concentration. In CKD, reduced glomerular filtration rate leads to various Pi metabolism abnormalities, and Pi absorption in the small intestine also has an important role in Pi metabolism. Disturbances in Pi metabolism are mediated by a series of complex changes in regulatory hormones originating from the skeleton, intestine, parathyroid gland, and kidney. In this review, we describe the regulation of type II sodium-dependent Pi co-transporters by the kidney and intestine, including the regulation of Pi transport, circadian rhythm, and the vicious circle between salivary Pi secretion and intestinal Pi absorption in animals with and without CKD.

en: Clinical and Experimental Nephrology

ja: Clinical and Experimental Nephrology

number: No.Suppl 1


en: Transcriptional regulation of sodium-phosphate cotransporter gene expression.

en: Molecular, Genetic, and Nutritional Aspects of Major and Trace Minerals


en: Vitamin D Nutrient-Gene Interactions and Healthful Aging

en: Molecular Basis of Nutrition and Aging

ja: Molecular Basis of Nutrition and Aging


en: The Role of Sodium-Dependent Phosphate Transporter in Phosphate Homeostasis.

en: Inorganic phosphate (Pi) is an essential compound for several biologic functions. Pi levels outside the normal range, however, contribute to several pathological processes. Hypophosphatemia leads to bone abnormalities, such as rickets/osteomalacia. Hyperphosphatemia contributes to vascular calcification in patients with chronic kidney disease and hemodialysis patients and is independently associated with cardiac mortality.Pi homeostasis is regulated by the coordinated function of renal and intestinal sodium-dependent phosphate (NaPi) transporters with dietary Pi, parathyroid hormone, 1,25-dihydroxyvitamin D3, and fibroblast growth factor 23. The type II NaPi transporter/SLC34 family, with three members identified to date, is mainly responsible for Pi homeostasis in the body. SLC34A1 and SCL34A3 are predominantly expressed in the kidney, whereas SLC34A2 is expressed in the small intestine. The role of each SLC34 in the body was recently established by studies of gene-targeted mice. Mutation of SLC34A1 causes Fanconi syndrome and mutation of SLC34A3 causes autosomal recessive hereditary hypophosphatemic rickets with hypercalciuria. SLC34A2 is thought to be a major intestinal NaPi transporter and mutation of SLC34A2 causes pulmonary alveolar microlithiasis. A detailed understanding of Pi regulation in the body is important toward maintaining health.

en: Journal of Nutritional Science and Vitaminology

volume: Vol.61 Suppl


en: Genetic diseases of renal phosphate handling

ja: 遺伝性リン代謝異常症

en: Japanese Journal of Nephrology

ja: 日本腎臓学会誌


en: Vitamin D and type II sodium-dependent phosphate cotransporters.

en: The type II sodium-dependent Pi (NaPi) cotransporters (NaPi-IIa, NaPi-IIb and NaPi-IIc) contribute to renal and intestinal Pi absorption. 1,25-Dihydroxyvitamin D [1,25(OH)2D3] is an important factor for NaPi-II transporters in the small intestine and kidney. In a previous study, low levels of 1,25(OH)2D3 appeared to suppress the expression of renal NaPi cotransporters. We identified a functional vitamin D receptor-responsive element in the human NaPi-IIa and NaPi-IIc genes in renal epithelial cells. In an analysis of vitamin D receptor (VDR)-null mice, we observed early onset of hypophosphatemia. The cause of the hypophosphatemia in VDR-null mice before weaning appeared to be increased plasma parathyroid hormone (PTH) levels during the suckling periods. A rescue diet (high calcium diet) decreased plasma PTH levels in VDR-null mice. The reduced plasma PTH levels normalized the renal Npt2a and Npt2c protein levels in weanling animals. Thus, the dietary intervention completely normalized the expression of the renal Pi transporters (Npt2a/Npt2c) in VDR-null mice, suggesting that the lack of VDR activity was not the cause of the impaired renal Pi reabsorption. In suckling animals, 1,25(OH)2D3 may be essential for the prevention of the phosphaturic action of PTH. In adult animals, 1,25(OH)2D3 is thought to be an important factor for posttranscriptional regulation of the Npt2b gene in the small intestine. Fibroblast growth factor 23 (FGF23) is a novel phosphaturic factor that influences vitamin D metabolism and renal reabsorption of Pi. We characterized the role of the VDR in the action of FGF23 using VDR-null mice. FGF23 reduced renal Pi transport and 25-hydroxyvitamin D 1a-hydroxylase levels by a mechanism that was independent of the VDR. By contrast, the induction of 25-hydroxyvitamin D 24-hydroxylase and the reduction in serum 1,25(OH)2D3 levels induced by FGF23 were dependent on the VDR. Thus, the VDR is not essential for the phosphaturic action of FGF23, but is essential for control of the plasma 1,25(OH)2D3 level. Moreover, FGF23 reduces intestinal NaPi transport activity and Npt2b protein levels by a mechanism that is dependent on the VDR. Klotho functions as a co-receptor for FGF23 and is increased by 1,25(OH)2D3. Klotho induces phosphaturia by inhibiting the renal NaPi-IIa transporter. In this review, we discuss the roles of 1,25(OH)2D3/VDR in the regulation of renal type II NaPi cotransporters in the kidney and small intestine.

en: Contributions to Nephrology

ja: Contributions to Nephrology


en: Molecular mechanisms of vitamin D action.

en: The hormonal metabolite of vitamin D, 1α,25-dihydroxyvitamin D(3) (1,25D), initiates biological responses via binding to the vitamin D receptor (VDR). When occupied by 1,25D, VDR interacts with the retinoid X receptor (RXR) to form a heterodimer that binds to vitamin D responsive elements in the region of genes directly controlled by 1,25D. By recruiting complexes of either coactivators or corepressors, ligand-activated VDR-RXR modulates the transcription of genes encoding proteins that promulgate the traditional functions of vitamin D, including signaling intestinal calcium and phosphate absorption to effect skeletal and calcium homeostasis. Thus, vitamin D action in a particular cell depends upon the metabolic production or delivery of sufficient concentrations of the 1,25D ligand, expression of adequate VDR and RXR coreceptor proteins, and cell-specific programming of transcriptional responses to regulate select genes that encode proteins that function in mediating the effects of vitamin D. For example, 1,25D induces RANKL, SPP1 (osteopontin), and BGP (osteocalcin) to govern bone mineral remodeling; TRPV6, CaBP(9k), and claudin 2 to promote intestinal calcium absorption; and TRPV5, klotho, and Npt2c to regulate renal calcium and phosphate reabsorption. VDR appears to function unliganded by 1,25D in keratinocytes to drive mammalian hair cycling via regulation of genes such as CASP14, S100A8, SOSTDC1, and others affecting Wnt signaling. Finally, alternative, low-affinity, non-vitamin D VDR ligands, e.g., lithocholic acid, docosahexaenoic acid, and curcumin, have been reported. Combined alternative VDR ligand(s) and 1,25D/VDR control of gene expression may delay chronic disorders of aging such as osteoporosis, type 2 diabetes, cardiovascular disease, and cancer.

en: Calcified Tissue International

ja: Calcified Tissue International


en: The role of vitamin D in the FGF23, klotho, and phosphate bone-kidney endocrine axis.

en: 1,25-dihydroxyvitamin D (1,25D), through association with the nuclear vitamin D receptor (VDR), exerts control over a novel endocrine axis consisting of the bone-derived hormone FGF23, and the kidney-expressed klotho, CYP27B1, and CYP24A1 genes, which together prevent hyperphosphatemia/ectopic calcification and govern the levels of 1,25D to maintain bone mineral integrity while promoting optimal function of other vital tissues. When occupied by 1,25D, VDR interacts with RXR to form a heterodimer that binds to VDREs in the region of genes directly controlled by 1,25D (e.g., FGF23, klotho, Npt2c, CYP27B1 and CYP24A1). By recruiting complexes of comodulators, activated VDR initiates a series of events that induces or represses the transcription of genes encoding proteins such as: the osteocyte-derived hormone, FGF23; the renal anti-senescence factor and protein co-receptor for FGF23, klotho; other mediators of phosphate transport including Npt2a/c; and vitamin D hormone metabolic enzymes, CYP27B1 and CYP24A1. The mechanism whereby osteocytes are triggered to release FGF23 is yet to be fully defined, but 1,25D, phosphate, and leptin appear to play major roles. The kidney responds to FGF23 to elicit CYP24A1-catalyzed detoxification of the 1,25D hormone while also repressing both Npt2a/c to mediate phosphate elimination and CYP27B1 to limit de novo 1,25D synthesis. Comprehension of these skeletal and renal actions of 1,25D should facilitate the development of novel mimetics to prevent ectopic calcification, chronic renal and vascular disease, and promote healthful aging.

en: Reviews in Endocrine & Metabolic Disorders


en: Sodium-dependent phosphate cotransporters: lessons from gene knockout and mutation studies.

en: Inorganic phosphate (Pi) is an essential physiological compound, highlighted by the syndromes caused by hypo or hyperphosphatemic states. Hyperphosphatemia is associated with ectopic calcification, cardiovascular disease, and increased mortality in patients with chronic kidney disease (CKD). As phosphate control is not efficient with diet or dialysis, oral Pi binders are used in over 90% of patients with renal failure. However, achieving tight control of serum Pi is difficult, and lower levels of serum Pi (severe hypophosphatemia) do not lead to better outcomes. The inhibition of sodium-dependent Pi (NaPi) transporter would be a preferable method to control serum Pi levels in patients with CKD or patients undergoing dialysis. Three types of NaPi transporters (types I-III) have been identified: solute carrier series SLC17A1 (NPT1/NaPi-I/OATv1), SLC34 (NaPi-IIa, NaPi-IIb, NaPi-IIc), and SLC20 (PiT1, PiT2), respectively. Knockout mice have been created for types I-III NaPi transporters. In this review, we discuss the roles of the NaPi transporters in Pi homeostasis.

en: Journal of Pharmaceutical Sciences

ja: Journal of Pharmaceutical Sciences


en: The roles of Na/Pi-II transporters in phosphate metabolism.

en: The renal type II Na/Pi cotransporters, Na/Pi-IIa and Na/Pi-IIc, are expressed in the brush border membrane (BBM) of the renal proximal tubule cells. Because it has long been thought that Na/Pi-IIa alone can regulate the reabsorption of phosphate in the proximal renal tubules, Na/Pi-IIc has not been paid much attention by the renal research community. Recent studies, however, have identified Na/Pi-IIc mutations as the defective cause of hereditary hypophosphatemic rickets with hypercalciuria (HHRH). This finding indicates that Na/Pi-IIc has a rather important role in renal Pi reabsorption and bone mineralization, and that it may be a key determinant of plasma Pi concentrations in humans. Studies of Na/Pi-IIc mice indicate that Na/Pi-IIc is necessary for normal calcium homeostasis, but its role in the regulation of Pi metabolism and bone physiology may be different from that in HHRH patients. Of note, Na/Pi-IIc KO mice display abnormal vitamin D regulation without hypophosphatemia or hyperphosphaturia. Thus, Na/Pi-IIc may be involved in regulating renal vitamin D synthesis in the proximal tubular cells. The identification of proteins that interact with Na/Pi-IIc is an important area of future research. The physiologic roles of Na/Pi-IIa and Na/Pi-IIc require future elucidation.

en: Bone

ja: Bone

volume: Vol.45 Suppl 1


en: 大豆たん白質摂取による心肥大抑制効果の検討.

ja: 大豆たん白質摂取による心肥大抑制効果の検討.

en: SOY PROTEIN RESEACH,

ja: 大豆たん白質研究.

misc_type: others