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PTH-CALCITONIN-VITAMIN D-BONE |
-Hydroxylase Gene
Department of Pathology and Tumor Biology (T.Y., T.F., Y.-I.N.), The Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; The Organization for Pharmaceutical Safety and Research (T.Y.), Tokyo, 100-0013 Japan; and Core Research for Evolutional Science and Technology (Y.-I.N.), Kawaguchi 332-0012, Japan
Address all correspondence and requests for reprints to: Yo-ichi Nabeshima, M.D., Ph.D., Department of Pathology and Tumor Biology, The Graduate School of Medicine, Kyoto University, Yoshida-Konoe cho, Sakyo-ku, Kyoto 606-8501, Japan. E-mail: nabemr{at}lmls.med.kyoto-u.ac.jp
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Abstract |
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-hydroxylase gene, the key enzyme of vitamin D metabolism, was also greatly enhanced in kidneys of kl-/- mice. Furthermore, the normal genetic responses to administered 1,25-(OH)2D3, such as down-regulation of the 25-hydroxyvitamin D 1-hydroxylase gene and up-regulation of 24-hydroxylase and VDR genes, were apparently impaired in kl-/- mice. These findings suggest that this deterioration in the vitamin D endocrine system may result in many of the phenotypes in kl-/- mice through effects of increased levels of calcium and phosphorus and 1,25-(OH)2D. Klotho protein may participate in calcium and phosphorus homeostasis via the regulation of the 1,25-(OH)2D signaling pathway. |
Introduction |
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Calcium concentrations in the serum are tightly regulated by the coordinated actions of PTH, calcitonin (CT), calcium, phosphorus, and 1,25-dihydroxyvitamin D [1,25-(OH)2D] (3, 4, 5, 6, 7, 8, 9, 10). These factors are mutually regulated, and their functions are influenced through complex interactions that maintain calcium and phosphorus homeostasis. For instance, PTH and CT positively regulate the synthesis of 1,25-(OH)2D via transcriptional activation of the 25-hydroxyvitamin D 1-hydroxylase (1-hydroxylase) gene (11, 12, 13). It is also known that the serum calcium level is critical for 1-hydroxylase activity; however, its regulation by calcium is considered to be indirect (14, 15). On the other hand, 1,25-(OH)2D inhibits its own synthesis by negative feedback regulation of 1-hydroxylase activity and by positive regulation of 24-hydroxylase activity (16, 17, 18).
As previously mentioned, serum levels of calcium [9.47 ± 0.30 mg/dl vs. 10.64 ± 1.07 mg/dl of wild-type (WT) and kl-/- mice, respectively] and phosphorus (8.54 ± 1.34 mg/dl vs. 15.09 ± 1.34 mg/dl of WT and kl-/- mice, respectively) in kl-/- mice were significantly higher than those of WT mice, and many of the phenotypes in kl-/- mice were presumed to be caused by this impaired calcium and phosphorus homeostasis. In this paper, we examined serum levels and gene expression of calciotropic factors and their functional interactions to investigate the molecular bases underlying abnormal calcium and phosphorus metabolism in kl-/- mice.
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Materials and Methods |
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1,25-(OH)2D3 administration
At 200 ng/100 g body weight of 1,25-(OH)2D3, Rocaltrol (Roche, Mannheim, Germany) was orally administered to five WT and kl-/- mice. The mice were anesthetized with avatin and killed at 3, 6, 12, and 24 h after the administration. Immediately after sacrifice, blood samples were collected and organs were dissected out, frozen in liquid nitrogen, and stored at -80 C for Northern or Western blotting analyses. Some tissues were stored at -80 C for cryostat sectioning.
RNA preparation and Northern analysis
Animals were killed, and kidneys and small intestine from both WT and kl-/- mice were collected. Total RNA was isolated and poly(A) RNA was extracted according to the manufacturer’s protocols (Total RNAgents and Poly Attract; Promega Corp., Madison, WI). Five micrograms of poly(A) RNA or 20 µg of total RNA were used per lane, and hybridization was performed with digoxigenin (DIG)-labeled cDNAs in a 50% formamide-based hybridization buffer. Detection of each mRNA was carried out using 0.5 kb of VDR cDNA corresponding to a part of the ligand-binding domain of VDR, 1.5 kb of 1-hydroxylase cDNA corresponding to entire cording sequence, and 1.6 kb of 24-hydroxylase cDNA corresponding to entire cording sequence, respectively. The exposure to x-ray film was performed using DIG detection system according to the manufacturer’s protocols (Roche Molecular Biochemicals, Mannheim, Germany). The images were captured by photoscanner (Linotype-Hell JADE ELS-2600; Linotype-Hell, Heidelberg, Germany) and processed by graphic software (Adobe Photoshop 6.0; Adobe Systems, Mountain View, CA). Densitometric data were presented as relative increments compared with nontreated controls.
Western blotting
Kidneys and small intestine from WT and kl-/- mice were homogenized with Physcotron (NS-310E, NITI-ON, Funabashi, Japan) and centrifuged at 1,000 x g for 10 min to prepare crude nuclear fractions. Aliquots of whole lysates taken before centrifugation and crude nuclear fractions were incubated with SDS sample buffer, separated on 10% SDS polyacrylamide gels, and electroblotted onto polyvinylidene difluoride membranes (Immobilon; Millipore Corp., Bedford, MA). Immunodetection was performed using rabbit polyclonal antibody raised against rat VDR (sc-1008; Santa Cruz Biotechnology, Inc., Santa Cruz, CA). After incubation with anti-VDR antibody, the membrane was incubated with goat antirabbit IgG-horseradish peroxidase [HRP (Amersham Pharmacia Biotech, Piscataway, NJ)]. Visualization of VDR protein was obtained by HRP chemiluminescence kit (ECL; Amersham Pharmacia Biotech) according to the manufacturer’s instructions.
Immunohistochemistry
Immunohistochemical analysis was performed on frozen kidneys and small intestine sections of WT and kl-/- mice. After fixation with 4% paraformaldehyde followed by permeabilization, a rabbit polyclonal anti-VDR antibody was used for immunostaining. Visualization was done by Alexa 594 antirabbit IgG (Molecular Probes, Inc., Eugene, OR). Confocal images were obtained through laser scanning microscopy (TCS SP2; Leica Corp., Heidelberg, Germany).
Statistical analyses
The significance of the difference between the means of two groups was analyzed by the t test, and differences were taken as statistically significant when P < 0.01 (**) or P < 0.05 (*).
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Results |
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, serum levels of PTH in kl-/- mice were slightly lower than those of WT at suckling and young adult stages and then subsequently decreased to less than 50% of WT levels (Fig. 1A). Serum levels of CT in kl-/- mice were higher than those in WT at all stages from suckling to adult (Fig. 1B). The serum levels of PTH and CT correlate with the increased levels of serum calcium in kl-/- mice, suggesting that the signaling pathways for PTH and CT synthesis can be normally controlled despite deficiency in the klotho gene product. On the other hand, serum levels of the third calciotropic hormone, 1,25-(OH)2D, in kl-/- mice were significantly higher than that of WT mice at all ages examined (Fig. 1C). This is a reversed response to high serum calcium, as it has been previously reported that 1,25-(OH)2D synthesis is down-regulated when serum calcium levels are increased (14, 15). The differences between kl-/- and WT mice were at their maximal and the serum levels of 1,25-(OH)2D of kl-/- mice were highest at 2 wk of age, before the occurrence of multiple histological phenotypes (Fig. 1C). The serum levels of other vitamin D derivatives such as 25-hydroxyvitamin D and 24,25-dyhidroxyvitamin D were found to be lower than that in WT mice (Fig. 1D), suggesting that 25-hydroxyvitamin D, the precursor of active and inactive forms, was preferentially converted to an active form of vitamin D in kl-/- mice. Among several endocrine indexes analyzed in kl-/- mice, the discrepancy in serum levels of 1,25-(OH)2D between WT and kl-/- mice is the earliest found to date regarding impaired calcium and phosphorus metabolism. We then hypothesized that abnormally high activation of vitamin D might occur in kl-/- mice and might induce impaired calcium and phosphorus metabolism. Therefore, we focused on the key molecules involved in regulating vitamin D activation.
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-hydroxylase and 24-hydroxylase genes in kl-/- and WT mice-hydroxylase and 24-hydroxylase, which are required for the regulation of the final rate limiting steps of vitamin D metabolism. Expression of the 1-hydroxylase gene was enhanced in the kidneys of kl-/- mice (Fig. 2A), whereas the levels of 24-hydroxylase mRNA was moderately increased in kl-/- mice compared with WT mice (Fig. 2B). The expression level of VDR mRNA in kl-/- mice was slightly reduced compared with WT mice in both the kidneys and small intestine (Fig. 2C). Meanwhile, VDR protein levels revealed that they were reduced significantly in the mutant kidneys and small intestine (Fig. 3, A and B). Histochemical analysis of VDR on the cryostat sections of kidneys and small intestine also demonstrated clear staining of WT nuclei (Fig. 3, D and G) and only weak staining of kl-/- nuclei (Fig. 3, E and H). The enhanced expression of the 1-hydroxylase gene likely induces the high serum levels of 1,25-(OH)2D in kl-/- mice. However, slightly reduced levels of VDR mRNA of kl-/- mice and significant reduction of VDR protein levels in kidneys and small intestine of kl-/- mice are not in accordance with previous studies that have reported up-regulation of both VDR mRNA and protein levels in response to high concentrations of 1,25-(OH)2D (22, 23, 24, 25). Furthermore, the expression levels of 1-hydroxylase and 24-hydroxylase mRNAs in kl-/- mice were not consistent with high serum 1,25-(OH)2D.
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-hydroxylase, and 24-hydroxylase-hydroxylase, and 24-hydroxylase gene regulation to investigate whether the positive and negative responses via VDR remain intact in the kidneys of kl-/- mice. In WT mice, up-regulation of VDR mRNA was observed at 3 h and later (increases of 
150–175% compared with nontreated controls) after administration of 1,25-(OH)2D in accordance with previous reports (Fig. 4A). However, up-regulation of VDR was not evident in kl-/- mice, although a slight increase was detected at 3 and 6 h (<110% compared with compared with nontreated controls) after the administration (Fig. 4B). To see whether this represents an altered response of VDR, we examined the expression profiles of two genes encoding vitamin D biosynthesis enzymes, 1-hydroxylase and 24-hydroxylase, after administration of 1,25-(OH)2D3. The 1-hydroxylase and 24-hydroxylase genes have been reported to be negatively and positively controlled via vitamin D responsive element in their promoters although the putative negative vitamin D responsive element seems not to retain a core motif (18, 26, 27). The reported results that administration of 1,25-(OH)2D3 down-regulates the 1-hydroxylase gene and up-regulates 24-hydroxylase gene were reproducible under our conditions in WT mice (Fig. 5, left, A and B). In kl-/- mice, however, down-regulation of 1-hydroxylase expression was not observed, and up-regulation of 24-hydroxylase gene expression was significantly reduced (Fig. 5, A and B, right). At 24 h after 1,25-(OH)2D3 administration, 24-hydroxylase mRNA was reduced to almost undetectable levels in kl-/- mice (data not shown), although serum 1,25-(OH)2D levels was still relatively high. These observations suggest that the enhanced production of 1-hydroxylase and low levels of 24-hydroxylase may be the major cause of increased 1,25-(OH)2D biosynthesis in kl-/- mice.
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Discussion |
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-hydroxylase and 24-hydroxylase, the vitamin D synthesis enzymes, in kidneys of mutant mice despite the high serum levels of 1,25-(OH)2D.
As reported, PTH and CT positively regulate the expression of the 1-hydroxylase gene and 1,25-(OH)2D negatively controls 1-hydroxylase expression via VDR. Furthermore, it has been shown that the negative regulatory signals from VDR can dominantly offset the signals from those positive regulators under normal condition (28). In kl-/- mice, CT levels in serum were high, and 1,25-(OH)2D, a functional antagonist of CT, was also increased. Thus, increased CT may be a possible cause of the rise in 1-hydroxylase levels. On the other hand, signals from active vitamin D via VDR seemed to be largely defunct in kl-/- mice because 1-hydroxylase expression could not be down regulated even in response to ectopic administration of 1,25-(OH)2D3. This suggested that signaling from active vitamin D might be severely altered in the mutant mice.
There are several hypotheses to explain the altered response of VDR to active vitamin D in kl-/- mice. One is desensitization of the active vitamin D signaling pathway. Exposure of VDR and related signaling molecules to continuously high levels of 1,25-(OH)2 D from early stages of development may result in an increased threshold or desensitization. A second hypothesis is a defect in the response of VDR to active vitamin D. It is possible that the signal transduction pathway is shut down by the inactivation of an important signaling molecule or by the activation of an unknown molecule, which interferes with the active vitamin D pathway. A third scenario is the activation of an extra signal that regulates the expression of 1-hydroxylase and 24-hydroxylase independent of VDR action. Our last case involves decreased VDR protein in kl-/- mice. We have shown decreased levels of VDR protein in both kidneys and small intestine by western blotting (Fig. 3
, A and B) and immunostaining (Fig. 3, E and H) in kl-/- mice. It is possible that the defect of Klotho protein or other modified factors driven by the defective function of Klotho protein may interfere the expression or the stability of VDR protein, and the reduced VDR protein levels may cause the abnormal responses of both 1-hydroxylase and 24-hydroxylase. In any event, the levels of VDR protein are substantially reduced and should not be excluded from consideration.
The next should be referred is how the defect of Klotho protein may lead to the impairment of vitamin D signal pathway. It has been shown that two types of Klotho protein exist that are encoded by a single locus and generated through alternative splicing; one is a membrane form with a single trans-membrane domain and the other is a shorter secreted form (29). Indeed, Klotho protein is secreted into the extra-cellular spaces and detected in the serum (Imura, A., unpublished data) in addition to the cellular surface of the distal convoluted tubule cells. Thus, Klotho potentially could function on the membrane and/or as a secreted factor. As reported (1), two internal repeats (KL1 and KL2) of Klotho proteins are characteristic for members of ß-glucosidase that belong to the family 1 glycoside hydrolases (30). Based on extensive examination of the enzyme functions of ß-glucosidase, two putative active centers have been identified (31). Within each putative active center, conserved glutamate residues are present that have been reported to be critical for the enzyme function. In both KL1 and KL2, glutamate residues have been replaced. In view of these alterations of critical amino acid residues, it has been speculated that Klotho protein may not possess the usual ß-glucosidase activity. However, the possibility remains that Klotho protein may catalyze particular substrate(s) under restricted conditions. It is also possible that Klotho protein may bind to the sugar moiety of the target molecule(s). As reported, 1-hydroxylase gene is expressed in the proximal convoluted tubule cells and also in a wide region of the uriniferous tubule cells (Ref. 32 and Tsujikawa, H., unpublished data). In contrast, klotho gene expression is restricted to the distal convoluted tubule cells in the kidney. To explain this apparently cell nonautonomous phenomena, it must be assumed that the function of Klotho protein is mediated via paracrine or intercellular mechanisms, at least in part. Based on these findings, we can propose several possible biological roles of Klotho protein from this point of view. The first is that Klotho protein converts inactive precursor molecules that participate in the vitamin D pathway to a biologically active form. The second might be that Klotho protein provides an interaction site for molecules involved in the vitamin D pathway. The third is that the secreted or membrane form of Klotho protein interacts with a presumptive receptor as a ligand molecule and then transduces the signal required for gene regulation of 1-hydroxylase. A fourth possibility is that Klotho protein acts as a receptor complex to mediate the signals required for the synthesis and/or secretion of critical humoral factors involved in control of the vitamin D pathway or 1-hydroxylase gene regulation. In any case, further investigation will be required to determine the definitive role of Klotho protein in the regulation of calcium and phosphorus metabolism.
Our study reveals that serum levels of 1,25-(OH)2D in kl-/- mice are greatly elevated. Impaired regulation of 1-hydroxylase and 24-hydroxylase expression could be, then, a major cause for unbalanced activation of vitamin D in the mutant. It still remains unclear which factors, including calcium, phosphorus, CT, PTH, 1,25-(OH)2D, and other unidentified factors, are the direct cause of these abnormal regulation of enzymes seen in kl-/- mice. However, our work demonstrates that calcium and phosphorus homeostasis can be regulated through Klotho function via the action of 1,25-(OH)2D.
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Acknowledgments |
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Footnotes |
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Abbreviations: 1,25-(OH)2D, 1,25-dihydroxyvitamin D; 1-hydroxylase, 25-hydroxyvitamin D 1-hydroxylase; CT, calcitonin; kl-/-, klotho mutant; DIG, digoxigenin; WT, wild type.
Received July 20, 2001.
Accepted for publication October 25, 2001.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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-hydroxylase cDNA. Proc Natl Acad Sci USA 94:12920–12925-hydroxylase gene confers positive and negative responsiveness to PTH, calcitonin, and 1 ,25-(OH)2D3. Biochem Biophys Res Commun 249:11–16[CrossRef][Medline]
-hydroxylase gene in normocalcemic rats. Proc Natl Acad Sci USA 96:8253–8258-hydroxylase activity by calcium and calcitonin in renal cortex from hypophosphatemic (Hyp) mice. Endocrinology 114:1203–1207[Abstract]
-hydroxylase and vitamin D synthesis. Science 277:1827–1830-hydroxylase gene by parathyroid hormone, calcitonin, and 1,25(OH)2D3 in intact animals. Endocrinology 140:2224–2231-hydroxylase. Mol Cell Endocrinol 151:213–220[CrossRef][Medline]This article has been cited by other articles:
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 X. Wu, H. Ge, J. Gupte, J. Weiszmann, G. Shimamoto, J. Stevens, N. Hawkins, B. Lemon, W. Shen, J. Xu, et al. Co-receptor Requirements for Fibroblast Growth Factor-19 Signaling J. Biol. Chem., October 5, 2007; 282(40): 29069 - 29072. [Abstract] [Full Text] [PDF]
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 A. Imura, Y. Tsuji, M. Murata, R. Maeda, K. Kubota, A. Iwano, C. Obuse, K. Togashi, M. Tominaga, N. Kita, et al. {alpha}-Klotho as a Regulator of Calcium Homeostasis Science, June 15, 2007; 316(5831): 1615 - 1618. [Abstract] [Full Text] [PDF]
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|
 J.-P. Stasch, P.M. Schmidt, P.I. Nedvetsky, T.Y. A. Nedvetskaya, H.S. Kumar, S. Meurer, M. Deile, A. Taye, A. Knorr, H. Lapp, et al. Endothelial Cell Dysfunction--Can One Outsmart Oxidative Stress by Direct Interaction with the Pathological Oxidized or Heme-Free Soluble Guanyl-Cyclase?: Targeting the Heme-Oxydized Nitric Oxide Receptor for Selective Vasodilatation of Diseased Blood Vessels. J Clin Invest 116: 2552-2561, 2006 J. Am. Soc. Nephrol., March 1, 2007; 18(3): 663 - 669. [Full Text] [PDF]
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 |
|
 H. Segawa, S. Yamanaka, Y. Ohno, A. Onitsuka, K. Shiozawa, F. Aranami, J. Furutani, Y. Tomoe, M. Ito, M. Kuwahata, et al. Correlation between hyperphosphatemia and type II Na-Pi cotransporter activity in klotho mice Am J Physiol Renal Physiol, February 1, 2007; 292(2): F769 - F779. [Abstract] [Full Text] [PDF]
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|
|
|
|
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S. Tsuruoka, K. Nishiki, T. Ioka, H. Ando, Y. Saito, M. Kurabayashi, R. Nagai, and A. Fujimura Defect in parathyroid-hormone-induced luminal calcium absorption in connecting tubules of Klotho mice Nephrol. Dial. Transplant., October 1, 2006; 21(10): 2762 - 2767. [Abstract] [Full Text] [PDF]
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 G. J. Strewler The Spinner Meets the Stone: Klotho and Mineral Metabolism IBMS BoneKEy, November 1, 2005; 2(11): 29 - 33. [Full Text] [PDF]
|
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|
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|
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A. S. Dusso, A. J. Brown, and E. Slatopolsky Vitamin D Am J Physiol Renal Physiol, July 1, 2005; 289(1): F8 - F28. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. E. Arking, G. Atzmon, A. Arking, N. Barzilai, and H. C. Dietz Association Between a Functional Variant of the KLOTHO Gene and High-Density Lipoprotein Cholesterol, Blood Pressure, Stroke, and Longevity Circ. Res., March 4, 2005; 96(4): 412 - 418. [Abstract] [Full Text] [PDF]
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|
|
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|
 M. H. Meyer, E. Dulde, and R. A. Meyer Jr. The genomic response of the mouse kidney to low-phosphate diet is altered in X-linked hypophosphatemia Physiol Genomics, June 17, 2004; 18(1): 4 - 11. [Abstract] [Full Text] [PDF]
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O. Tohyama, A. Imura, A. Iwano, J.-N. Freund, B. Henrissat, T. Fujimori, and Y.-i. Nabeshima Klotho Is a Novel {beta}-Glucuronidase Capable of Hydrolyzing Steroid {beta}-Glucuronides J. Biol. Chem., March 12, 2004; 279(11): 9777 - 9784. [Abstract] [Full Text] [PDF]
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H. Tsujikawa, Y. Kurotaki, T. Fujimori, K. Fukuda, and Y.-I. Nabeshima Klotho, a Gene Related to a Syndrome Resembling Human Premature Aging, Functions in a Negative Regulatory Circuit of Vitamin D Endocrine System Mol. Endocrinol., December 1, 2003; 17(12): 2393 - 2403. [Abstract] [Full Text] [PDF]
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K.-I. Miyamoto, M. Ito, H. Segawa, and M. Kuwahata Molecular targets of hyperphosphataemia in chronic renal failure Nephrol. Dial. Transplant., March 1, 2003; 18(90003): iii79 - 80. [Abstract] [Full Text] [PDF]
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T. Yamashita, S. Okada, K. Higashio, Y.-i. Nabeshima, and M. Noda Double Mutations in Klotho and Osteoprotegerin Gene Loci Rescued Osteopetrotic Phenotype Endocrinology, December 1, 2002; 143(12): 4711 - 4717. [Abstract] [Full Text] [PDF]
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H. Manya, M. Inomata, T. Fujimori, N. Dohmae, Y. Sato, K. Takio, Y.-i. Nabeshima, and T. Endo Klotho Protein Deficiency Leads to Overactivation of {micro}-Calpain J. Biol. Chem., September 13, 2002; 277(38): 35503 - 35508. [Abstract] [Full Text] [PDF]
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