1
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Portales-Castillo I, Rieg T, Khalid SB, Nigwekar SU, Neyra JA. Physiopathology of Phosphate Disorders. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:177-188. [PMID: 36868732 PMCID: PMC10565570 DOI: 10.1053/j.akdh.2022.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/24/2022] [Accepted: 12/29/2022] [Indexed: 03/05/2023]
Abstract
Intracellular phosphate is critical for cellular processes such as signaling, nucleic acid synthesis, and membrane function. Extracellular phosphate (Pi) is an important component of the skeleton. Normal levels of serum phosphate are maintained by the coordinated actions of 1,25-dihydroxyvitamin D3, parathyroid hormone and fibroblast growth factor-23, which intersect in the proximal tubule to control the reabsorption of phosphate via the sodium-phosphate cotransporters Npt2a and Npt2c. Furthermore, 1,25-dihydroxyvitamin D3 participates in the regulation of dietary phosphate absorption in the small intestine. Clinical manifestations associated with abnormal serum phosphate levels are common and occur as a result of genetic or acquired conditions affecting phosphate homeostasis. For example, chronic hypophosphatemia leads to osteomalacia in adults and rickets in children. Acute severe hypophosphatemia can affect multiple organs leading to rhabdomyolysis, respiratory dysfunction, and hemolysis. Patients with impaired kidney function, such as those with advanced CKD, have high prevalence of hyperphosphatemia, with approximately two-thirds of patients on chronic hemodialysis in the United States having serum phosphate levels above the recommended goal of 5.5 mg/dL, a cutoff associated with excess risk of cardiovascular complications. Furthermore, patients with advanced kidney disease and hyperphosphatemia (>6.5 mg/dL) have almost one-third excess risk of death than those with phosphate levels between 2.4 and 6.5 mg/dL. Given the complex mechanisms that regulate phosphate levels, the interventions to treat the various diseases associated with hypophosphatemia or hyperphosphatemia rely on the understanding of the underlying pathobiological mechanisms governing each patient condition.
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Affiliation(s)
- Ignacio Portales-Castillo
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA; Endocrine Unit, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL; James A. Haley Veterans' Hospital, Tampa, FL; Center for Hypertension and Kidney Research, University of South Florida, Tampa, FL
| | - Sheikh B Khalid
- Department of Internal Medicine, The Indus Hospital, Lahore Pakistan
| | - Sagar U Nigwekar
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
| | - Javier A Neyra
- Department of Internal Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL.
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2
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Kateshiya MR, Malek NI, Kailasa SK. Synthesis of blue fluorescent molybdenum nanoclusters with novel terephthaldehyde-cysteine Schiff base for detection of pyrophosphate. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 280:121536. [PMID: 35752042 DOI: 10.1016/j.saa.2022.121536] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 06/01/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
In this work, terephthaldehyde-cysteine-molybdenum nanoclusters (TPA-Cys-MoNCs) were synthesized by using terephthaldehyde-cysteine (TPA-Cys) Schiff base as a novel ligand. The as-synthesized TPA-Cys-MoNCs showed blue fluorescence under UV lamp at 365 nm, displaying emission peak at 455 nm when excited at 340 nm. The fluorescent TPA-Cys-MoNCs are used as a probe for sensitive assay of pyrophosphate (PPi) via fluorescence quenching mechanism. The emission peak intensity of TPA-Cys-MoNCs at 455 nm exhibited a linear quenching with increasing amount of PPi. As a result, quantitative assay was developed for the detection of PPi (0.01-200 µM) with the detection limit of 0.9 nM. The developed probe was successfully demonstrated for the detection of PPi in biofluids (urine and plasma).
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Affiliation(s)
- Mehul R Kateshiya
- Department of Chemistry, Sardar Vallbhbhai National Institute of Technology, Surat 395 007, Gujarat, India
| | - Naved I Malek
- Department of Chemistry, Sardar Vallbhbhai National Institute of Technology, Surat 395 007, Gujarat, India
| | - Suresh Kumar Kailasa
- Department of Chemistry, Sardar Vallbhbhai National Institute of Technology, Surat 395 007, Gujarat, India.
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3
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Wang W, Wang B, Liu H, Liu Q, Li S, Zhao B, Gao Y. A Naphthalimides‐Based Probe for Sequential Detection of Cu
2+
and PPi and Its Application in Cells Imaging. ChemistrySelect 2022. [DOI: 10.1002/slct.202201304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Wei Wang
- School of Perfume and Aroma Technology Shanghai Institute of Technology Shanghai 201418 China
| | - Baihui Wang
- School of Perfume and Aroma Technology Shanghai Institute of Technology Shanghai 201418 China
| | - Huimin Liu
- School of Perfume and Aroma Technology Shanghai Institute of Technology Shanghai 201418 China
| | - Qinglei Liu
- School of Perfume and Aroma Technology Shanghai Institute of Technology Shanghai 201418 China
| | - Shanshan Li
- School of Perfume and Aroma Technology Shanghai Institute of Technology Shanghai 201418 China
| | - Bing Zhao
- Chemistry and Chemical Engineering Institute Qiqihar University Qiqihar 161006 China
| | - Yan Gao
- School of Chemical Engineering University of Science and Technology Liaoning Anshan 114051 China
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4
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J S, P R, S R. Solvent free synthesis and spectral analysis of 2,4-dimethyl-6-(1-phenyl-1H-benzimidazol-2-yl)phenol: on/off fluorescence, inter and intramolecular hydrogen bonding. INORG NANO-MET CHEM 2022. [DOI: 10.1080/24701556.2022.2076697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Sivapriya J
- Department of Chemistry, St. Joseph’s Institute of Technology, Chennai, Tamilnadu, India
| | - Ravichandran P
- Department of Chemical Engineering, St. Joseph’s Institute of Technology, Chennai, Tamilnadu, India
| | - Renganathan S
- Department of Biotechnology, Anna University, Chennai, Tamil Nadu, India
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5
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Common Dietary Sources of Natural and Artificial Phosphate in Food. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:99-105. [DOI: 10.1007/978-3-030-91623-7_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Bird RP, Eskin NAM. The emerging role of phosphorus in human health. ADVANCES IN FOOD AND NUTRITION RESEARCH 2021; 96:27-88. [PMID: 34112356 DOI: 10.1016/bs.afnr.2021.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Phosphorus, an essential nutrient, performs vital functions in skeletal and non-skeletal tissues and is pivotal for energy production. The last two decades of research on the physiological importance of phosphorus have provided several novel insights about its dynamic nature as a nutrient performing functions as a phosphate ion. Phosphorous also acts as a signaling molecule and induces complex physiological responses. It is recognized that phosphorus homeostasis is critical for health. The intake of phosphorus by the general population world-wide is almost double the amount required to maintain health. This increase is attributed to the incorporation of phosphate containing food additives in processed foods purchased by consumers. Research findings assessed the impact of excessive phosphorus intake on cells' and organs' responses, and highlighted the potential pathogenic consequences. Research also identified a new class of bioactive phosphates composed of polymers of phosphate molecules varying in chain length. These polymers are involved in metabolic responses including hemostasis, brain and bone health, via complex mechanism(s) with positive or negative health effects, depending on their chain length. It is amazing, that phosphorus, a simple element, is capable of exerting multiple and powerful effects. The role of phosphorus and its polymers in the renal and cardiovascular system as well as on brain health appear to be important and promising future research directions.
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Affiliation(s)
- Ranjana P Bird
- School of Health Sciences, University of Northern British Columbia, Prince George, BC, Canada.
| | - N A Michael Eskin
- Department of Food and Human Nutritional Sciences, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, MB, Canada
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7
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Highly Selective Recognition of Pyrophosphate by a Novel Coumarin-Iron (III) Complex and the Application in Living Cells. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9030048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In this paper, a novel NL-Fe3+ ensemble was designed as a fluorescent chemosensor for highly selective detection of pyrophosphate (PPi) in DMSO/H2O (2:8/v:v, pH = 7.2) solution and living cells. NL showed a strong affinity for Fe3+ and was accompanied by obvious fluorescence quenching. Upon the addition of PPi to the generated NL-Fe3+ ensemble, the fluorescence and absorption spectra were recovered completely. Spectroscopic investigation showed that the interference provoked by common anions such as adenosine-triphosphate (ATP), adenosine diphosphate (ADP), and phosphates (Pi) can be ignored. The detection limit of NL-Fe3+ to PPi was calculated to be 1.45 × 10−8 M. Intracellular imaging showed that NL-Fe3+ has good membrane permeability and could be used for the detection of PPi in living cells. A B3LYP/6-31G(d,p) basis set was used to optimize NL and NL-Fe3+ complex.
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8
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Huang HW, Xin ZH, Nan JZ, Chen Y, Cao QY. A new imidazolium/sulfonamide linked ferrocene-dansyl dyad for dual-channel recognition of anion. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2020.120026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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The Roles of Sodium-Independent Inorganic Phosphate Transporters in Inorganic Phosphate Homeostasis and in Cancer and Other Diseases. Int J Mol Sci 2020; 21:ijms21239298. [PMID: 33291240 PMCID: PMC7729900 DOI: 10.3390/ijms21239298] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/29/2020] [Accepted: 12/02/2020] [Indexed: 12/13/2022] Open
Abstract
Inorganic phosphate (Pi) is an essential nutrient for the maintenance of cells. In healthy mammals, extracellular Pi is maintained within a narrow concentration range of 0.70 to 1.55 mM. Mammalian cells depend on Na+/Pi cotransporters for Pi absorption, which have been well studied. However, a new type of sodium-independent Pi transporter has been identified. This transporter assists in the absorption of Pi by intestinal cells and renal proximal tubule cells and in the reabsorption of Pi by osteoclasts and capillaries of the blood–brain barrier (BBB). Hyperphosphatemia is a risk factor for mineral deposition, the development of diseases such as osteoarthritis, and vascular calcifications (VCs). Na+-independent Pi transporters have been identified and biochemically characterized in vascular smooth muscle cells (VSMCs), chondrocytes, and matrix vesicles, and their involvement in mineral deposition in the extracellular microenvironment has been suggested. According to the growth rate hypothesis, cancer cells require more phosphate than healthy cells due to their rapid growth rates. Recently, it was demonstrated that breast cancer cells (MDA-MB-231) respond to high Pi concentration (2 mM) by decreasing Na+-dependent Pi transport activity concomitant with an increase in Na+-independent (H+-dependent) Pi transport. This Pi H+-dependent transport has a fundamental role in the proliferation and migratory capacity of MDA-MB-231 cells. The purpose of this review is to discuss experimental findings regarding Na+-independent inorganic phosphate transporters and summarize their roles in Pi homeostasis, cancers and other diseases, such as osteoarthritis, and in processes such as VC.
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10
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Serna J, Bergwitz C. Importance of Dietary Phosphorus for Bone Metabolism and Healthy Aging. Nutrients 2020; 12:E3001. [PMID: 33007883 PMCID: PMC7599912 DOI: 10.3390/nu12103001] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/25/2020] [Accepted: 09/26/2020] [Indexed: 12/13/2022] Open
Abstract
Inorganic phosphate (Pi) plays a critical function in many tissues of the body: for example, as part of the hydroxyapatite in the skeleton and as a substrate for ATP synthesis. Pi is the main source of dietary phosphorus. Reduced bioavailability of Pi or excessive losses in the urine causes rickets and osteomalacia. While critical for health in normal amounts, dietary phosphorus is plentiful in the Western diet and is often added to foods as a preservative. This abundance of phosphorus may reduce longevity due to metabolic changes and tissue calcifications. In this review, we examine how dietary phosphorus is absorbed in the gut, current knowledge about Pi sensing, and endocrine regulation of Pi levels. Moreover, we also examine the roles of Pi in different tissues, the consequences of low and high dietary phosphorus in these tissues, and the implications for healthy aging.
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Affiliation(s)
- Juan Serna
- Yale College, Yale University, New Haven, CT 06511, USA;
| | - Clemens Bergwitz
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06519, USA
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11
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Pal S, Ghosh TK, Ghosh R, Mondal S, Ghosh P. Recent advances in recognition, sensing and extraction of phosphates: 2015 onwards. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2019.213128] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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12
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King AJ, Siegel M, He Y, Nie B, Wang J, Koo-McCoy S, Minassian NA, Jafri Q, Pan D, Kohler J, Kumaraswamy P, Kozuka K, Lewis JG, Dragoli D, Rosenbaum DP, O'Neill D, Plain A, Greasley PJ, Jönsson-Rylander AC, Karlsson D, Behrendt M, Strömstedt M, Ryden-Bergsten T, Knöpfel T, Pastor Arroyo EM, Hernando N, Marks J, Donowitz M, Wagner CA, Alexander RT, Caldwell JS. Inhibition of sodium/hydrogen exchanger 3 in the gastrointestinal tract by tenapanor reduces paracellular phosphate permeability. Sci Transl Med 2019; 10:10/456/eaam6474. [PMID: 30158152 DOI: 10.1126/scitranslmed.aam6474] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 10/31/2017] [Accepted: 03/06/2018] [Indexed: 12/16/2022]
Abstract
Hyperphosphatemia is common in patients with chronic kidney disease and is increasingly associated with poor clinical outcomes. Current management of hyperphosphatemia with dietary restriction and oral phosphate binders often proves inadequate. Tenapanor, a minimally absorbed, small-molecule inhibitor of the sodium/hydrogen exchanger isoform 3 (NHE3), acts locally in the gastrointestinal tract to inhibit sodium absorption. Because tenapanor also reduces intestinal phosphate absorption, it may have potential as a therapy for hyperphosphatemia. We investigated the mechanism by which tenapanor reduces gastrointestinal phosphate uptake, using in vivo studies in rodents and translational experiments on human small intestinal stem cell-derived enteroid monolayers to model ion transport physiology. We found that tenapanor produces its effect by modulating tight junctions, which increases transepithelial electrical resistance (TEER) and reduces permeability to phosphate, reducing paracellular phosphate absorption. NHE3-deficient monolayers mimicked the phosphate phenotype of tenapanor treatment, and tenapanor did not affect TEER or phosphate flux in the absence of NHE3. Tenapanor also prevents active transcellular phosphate absorption compensation by decreasing the expression of NaPi2b, the major active intestinal phosphate transporter. In healthy human volunteers, tenapanor (15 mg, given twice daily for 4 days) increased stool phosphorus and decreased urinary phosphorus excretion. We determined that tenapanor reduces intestinal phosphate absorption predominantly through reduction of passive paracellular phosphate flux, an effect mediated exclusively via on-target NHE3 inhibition.
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Affiliation(s)
| | | | - Ying He
- Ardelyx Inc., Fremont, CA 94555, USA
| | | | - Ji Wang
- Ardelyx Inc., Fremont, CA 94555, USA
| | | | | | | | - Deng Pan
- Ardelyx Inc., Fremont, CA 94555, USA
| | | | | | | | | | | | | | - Debbie O'Neill
- University of Alberta, Edmonton, Alberta T6G 1C9, Canada
| | - Allein Plain
- University of Alberta, Edmonton, Alberta T6G 1C9, Canada
| | - Peter J Greasley
- Cardiovascular and Metabolic Disease (CVMD) Translational Medicine Unit, Early Clinical Development, Innovative Medicines and Early Development (IMED) Biotech Unit, AstraZeneca Gothenburg, 431 50 Mölndal, Sweden
| | | | - Daniel Karlsson
- Bioscience, CVMD, IMED Biotech Unit, AstraZeneca Gothenburg, 431 50 Mölndal, Sweden
| | - Margareta Behrendt
- Bioscience, CVMD, IMED Biotech Unit, AstraZeneca Gothenburg, 431 50 Mölndal, Sweden
| | - Maria Strömstedt
- Bioscience, CVMD, IMED Biotech Unit, AstraZeneca Gothenburg, 431 50 Mölndal, Sweden
| | | | - Thomas Knöpfel
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney Control of Homeostasis, CH-8057 Zurich, Switzerland
| | - Eva M Pastor Arroyo
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney Control of Homeostasis, CH-8057 Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney Control of Homeostasis, CH-8057 Zurich, Switzerland
| | - Joanne Marks
- Department of Neuroscience, Physiology and Pharmacology, University College London, Royal Free Campus, London NW3 2PF, UK
| | - Mark Donowitz
- Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney Control of Homeostasis, CH-8057 Zurich, Switzerland
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13
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Abstract
Inorganic phosphate (Pi) is essential for signal transduction and cell metabolism, and is also an essential structural component of the extracellular matrix of the skeleton. Pi is sensed in bacteria and yeast at the plasma membrane, which activates intracellular signal transduction to control the expression of Pi transporters and other genes that control intracellular Pi levels. In multicellular organisms, Pi homeostasis must be maintained in the organism and at the cellular level, requiring an endocrine and metabolic Pi-sensing mechanism, about which little is currently known. This Review will discuss the metabolic effects of Pi, which are mediated by Pi transporters, inositol pyrophosphates and SYG1-Pho81-XPR1 (SPX)-domain proteins to maintain cellular phosphate homeostasis in the musculoskeletal system. In addition, we will discuss how Pi is sensed by the human body to regulate the production of fibroblast growth factor 23 (FGF23), parathyroid hormone and calcitriol to maintain serum levels of Pi in a narrow range. New findings on the crosstalk between iron and Pi homeostasis in the regulation of FGF23 expression will also be outlined. Mutations in components of these metabolic and endocrine phosphate sensors result in genetic disorders of phosphate homeostasis, cardiomyopathy and familial basal ganglial calcifications, highlighting the importance of this newly emerging area of research.
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Affiliation(s)
- Sampada Chande
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, USA
| | - Clemens Bergwitz
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, USA.
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14
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Aniteli TM, de Siqueira FR, Dos Reis LM, Dominguez WV, de Oliveira EMC, Castelucci P, Moysés RMA, Jorgetti V. Effect of variations in dietary Pi intake on intestinal Pi transporters (NaPi-IIb, PiT-1, and PiT-2) and phosphate-regulating factors (PTH, FGF-23, and MEPE). Pflugers Arch 2018; 470:623-632. [PMID: 29372301 DOI: 10.1007/s00424-018-2111-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 11/29/2022]
Abstract
Hyperphosphatemia is a common condition in patients with chronic kidney disease (CKD) and can lead to bone disease, vascular calcification, and increased risks of cardiovascular disease and mortality. Inorganic phosphate (Pi) is absorbed in the intestine, an important step in the maintenance of homeostasis. In CKD, it is not clear to what extent Pi absorption is modulated by dietary Pi. Thus, we investigated 5/6 nephrectomized (Nx) Wistar rats to test whether acute variations in dietary Pi concentration over 2 days would alter hormones involved in Pi metabolism, expression of sodium-phosphate cotransporters, apoptosis, and the expression of matrix extracellular phosphoglycoprotein (MEPE) in different segments of the small intestine. The animals were divided into groups receiving different levels of dietary phosphate: low (Nx/LPi), normal (Nx/NPi), and high (Nx/HPi). Serum phosphate, fractional excretion of phosphate, intact serum fibroblast growth factor 23 (FGF-23), and parathyroid hormone (PTH) were significantly higher and ionized calcium was significantly lower in the Nx/HPi group than in the Nx/LPi group. The expression levels of NaPi-IIb and PiT-1/2 were increased in the total jejunum mucosa of the Nx/LPi group compared with the Nx/HPi group. Modification of Pi concentration in the diet affected the apoptosis of enterocytes, particularly with Pi overload. MEPE expression was higher in the Nx/HPi group than in the Nx/NPi. These data reveal the importance of early control of Pi in uremia to prevent an increase in serum PTH and FGF-23. Uremia may be a determining factor that explains the expressional modulation of the cotransporters in the small intestine segments.
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Affiliation(s)
| | | | | | | | | | - Patrícia Castelucci
- Department of Anatomy, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil
| | - Rosa Maria Affonso Moysés
- Medical School, Division of Nephrology, Universidade de São Paulo, São Paulo, Brazil.,Universidade Nove de Julho - UNINOVE, São Paulo, Brazil
| | - Vanda Jorgetti
- Medical School, Division of Nephrology, Universidade de São Paulo, São Paulo, Brazil. .,Faculdade de Medicina, Serviço de Nefrologia, Universidade de São Paulo, Av. Dr. Arnaldo, 455, 3° andar, sala 3342, São Paulo, SP, 01246-903, Brazil.
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15
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Osmolality of Orally Administered Solutions Influences Luminal Water Volume and Drug Absorption in Intestine. J Pharm Sci 2017; 106:2889-2894. [DOI: 10.1016/j.xphs.2017.04.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/14/2017] [Accepted: 04/17/2017] [Indexed: 12/14/2022]
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16
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Candeal E, Caldas YA, Guillén N, Levi M, Sorribas V. Intestinal phosphate absorption is mediated by multiple transport systems in rats. Am J Physiol Gastrointest Liver Physiol 2017; 312:G355-G366. [PMID: 28232455 DOI: 10.1152/ajpgi.00244.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 01/30/2017] [Accepted: 02/04/2017] [Indexed: 01/31/2023]
Abstract
Apical inorganic phosphate (Pi) transport in the small intestine seems to be mainly mediated by the sodium/Pi cotransporter NaPi2b. To verify this role, we have studied the combined effects of pH, phosphonoformate, and Pi deprivation on intestinal Pi transport. Rats were fed, ad libitum, three fodders containing 1.2, 0.6, or 0.1% Pi for 1, 5, or 10 days. Pi deprivation (0.1%) increased both sodium-activated and sodium-independent Pi transport in brush-border membrane vesicles from the duodenum and jejunum for all three times. Alkaline pH inhibited Pi transport, despite the increasing concentration of [Formula: see text] (NaPi2b substrate), whereas acidity increased transport when the concentration of the PiT1/PiT2 substrate, [Formula: see text], was at its highest. The effect of Pi deprivation was maximal at acid pH, but both basal and upregulated transport were inhibited (70%) with phosphonoformate, an inhibitor of NaPi2b. PiT2 and NaPi2b protein abundance increased after 24 h of Pi deprivation in the duodenum, jejunum, and ileum, whereas PiT1 required 5-10 days in the duodenum and jejunum. Therefore, whereas transporter expressions are partially correlated with Pi transport adaptation, the pH effect precludes NaPi2b, and phosphonoformic acid precludes PiT1 and PiT2 as the main transporters. Transport and transporter expression were also inconsistent when feeding was limited to 4 h daily, because the 1.2% Pi diet paradoxically increased Pi transport in the duodenum and jejunum, but NaPi2b and PiT1 expressions only increased with the 0.1% diet. These findings suggest the presence of a major transporter that carries [Formula: see text] and is inhibited by phosphonoformate.NEW & NOTEWORTHY The combined effects of dietary inorganic phosphate (Pi) content, pH, and phosphonoformate inhibition suggest that the resulting apical Pi transport in the small intestine cannot be fully explained by the presence of NaPi2b, PiT1, or PiT2. We provide evidence of the presence of a new sodium-coupled Pi transporter that uses [Formula: see text] as the preferred substrate and is inhibited by phosphonoformate, and its expression correlates with Pi transport in all assayed conditions.
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Affiliation(s)
- Eduardo Candeal
- Department of Toxicology, University of Zaragoza, Zaragoza, Spain; and
| | - Yupanqui A Caldas
- Department of Toxicology, University of Zaragoza, Zaragoza, Spain; and.,Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Natalia Guillén
- Department of Toxicology, University of Zaragoza, Zaragoza, Spain; and
| | - Moshe Levi
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Víctor Sorribas
- Department of Toxicology, University of Zaragoza, Zaragoza, Spain; and
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17
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Lee GJ, Mossa-Al Hashimi L, Debnam ES, Unwin RJ, Marks J. Postprandial adjustments in renal phosphate excretion do not involve a gut-derived phosphaturic factor. Exp Physiol 2017; 102:462-474. [PMID: 28130860 DOI: 10.1113/ep086062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 01/16/2017] [Indexed: 12/20/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a previously hypothesized signalling mechanism, believed to detect postprandial increases in intestinal phosphate and that can stimulate the kidneys to rapidly excrete phosphate, operate under physiological conditions? What is the main finding and its importance? Contrary to earlier reports, rapid signalling between the small intestine and kidney mediated by a gut-derived phosphaturic factor in response to a physiological intestinal phosphate load is not supported by the present findings; moreover, hyperphosphataemia and increased parathyroid hormone concentrations are likely to be the underlying factors responsible for the phosphaturia following a supraphysiological intestinal phosphate load. To date, the role of the small intestine in the regulation of postprandial phosphate homeostasis has remained unclear and controversial. Previous studies have proposed the presence of a gut-derived phosphaturic factor that acts independently of changes in plasma phosphate concentration or parathyroid hormone (PTH) concentration; however, these early studies used duodenal luminal phosphate concentrations in the molar range, and therefore, the physiological relevance of this is uncertain. In the present study, we used both in vivo and in vitro approaches to investigate the presence of this putative 'intestinal phosphatonin'. Instillation of 1.3 m phosphate into the duodenum rapidly induced phosphaturia, but in contrast to previous reports, this was associated with significant hyperphosphataemia and elevated PTH concentration; however, there was not the expected decrease in abundance of the renal sodium-phosphate cotransporter NaPi-IIa. Instillation of a physiological (10 mm) phosphate load had no effect on plasma phosphate concentration, PTH concentration or phosphate excretion. Moreover, phosphate uptake by opossum kidney cells was unaffected after incubation with serosal fluid collected from intestinal segments perfused with different concentrations of phosphate. Taken together, these findings do not support the concept of a gut-derived phosphaturic factor that can mediate rapid signalling between the gut and kidney, leading to increased urinary phosphate excretion, as part of normal phosphate homeostasis.
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Affiliation(s)
- Grace J Lee
- Centre for Nephrology, University College London, London, NW3 2PF, UK
| | - Lina Mossa-Al Hashimi
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
| | - Edward S Debnam
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
| | - Robert J Unwin
- Centre for Nephrology, University College London, London, NW3 2PF, UK.,Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
| | - Joanne Marks
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
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18
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Wongkongkatep J, Ojida A, Hamachi I. Fluorescence Sensing of Inorganic Phosphate and Pyrophosphate Using Small Molecular Sensors and Their Applications. Top Curr Chem (Cham) 2017; 375:30. [PMID: 28251566 DOI: 10.1007/s41061-017-0120-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/01/2017] [Indexed: 01/08/2023]
Abstract
The aim of this contribution is to provide an introduction and a brief summary of the principle of fluorescence molecular sensors specific to inorganic phosphate (Pi) and inorganic pyrophosphate (PPi) as well as their applications. In our introduction we describe the impact of both Pi and PPi in the living organism and in the environment, followed by a description of the principle of fluorescence molecular sensors and the sensing mechanism in solution. We then focus on exciting research which has emerged in recent years on the development of fluorescent sensors specific to Pi and PPi, categorized by chemical interactions between the sensor and the target molecule, such as hydrogen bonding, coordination chemistry, displacement assay, aggregation induced emission or quenching, and chemical reactions.
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Affiliation(s)
- Jirarut Wongkongkatep
- Department of Biotechnology, Faculty of Science, Mahidol University, 272 Rama 6 Road, Bangkok, 10400, Thailand
| | - Akio Ojida
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan.
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Hernando N, Myakala K, Simona F, Knöpfel T, Thomas L, Murer H, Wagner CA, Biber J. Intestinal Depletion of NaPi-IIb/Slc34a2 in Mice: Renal and Hormonal Adaptation. J Bone Miner Res 2015; 30:1925-37. [PMID: 25827490 DOI: 10.1002/jbmr.2523] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 03/26/2015] [Accepted: 03/27/2015] [Indexed: 11/10/2022]
Abstract
The Na(+) -dependent phosphate-cotransporter NaPi-IIb (SLC34A2) is widely expressed, with intestine, lung, and testis among the organs with highest levels of mRNA abundance. In mice, the intestinal expression of NaPi-IIb is restricted to the ileum, where the cotransporter localizes specifically at the brush border membrane (BBM) and mediates the active transport of inorganic phosphate (Pi). Constitutive full ablation of NaPi-IIb is embryonically lethal whereas the global but inducible removal of the transporter in young mice leads to intestinal loss of Pi and lung calcifications. Here we report the generation of a constitutive but intestinal-specific NaPi-IIb/Slc34a2-deficient mouse model. Constitutive intestinal ablation of NaPi-IIb results in viable pups with normal growth. Homozygous mice are characterized by fecal wasting of Pi and complete absence of Na/Pi cotransport activity in BBM vesicles (BBMVs) isolated from ileum. In contrast, the urinary excretion of Pi is reduced in these animals. The plasma levels of Pi are similar in wild-type and NaPi-IIb-deficient mice. In females, the reduced phosphaturia associates with higher expression of NaPi-IIa and higher Na/Pi cotransport activity in renal BBMVs, as well as with reduced plasma levels of intact FGF-23. A similar trend is found in males. Thus, NaPi-IIb is the only luminal Na(+) -dependent Pi transporter in the murine ileum and its absence is fully compensated for in adult females by a mechanism involving the bone-kidney axis. The contribution of this mechanism to the adaptive response is less apparent in adult males.
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Affiliation(s)
- Nati Hernando
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
| | - Komuraiah Myakala
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
| | - Fabia Simona
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
| | - Thomas Knöpfel
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
| | - Linto Thomas
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
| | - Heini Murer
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
| | - Jürg Biber
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP). University of Zurich, Zurich, Switzerland
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