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Jennings ML. Role of transporters in regulating mammalian intracellular inorganic phosphate. Front Pharmacol 2023; 14:1163442. [PMID: 37063296 PMCID: PMC10097972 DOI: 10.3389/fphar.2023.1163442] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/17/2023] [Indexed: 03/31/2023] Open
Abstract
This review summarizes the current understanding of the role of plasma membrane transporters in regulating intracellular inorganic phosphate ([Pi]In) in mammals. Pi influx is mediated by SLC34 and SLC20 Na+-Pi cotransporters. In non-epithelial cells other than erythrocytes, Pi influx via SLC20 transporters PiT1 and/or PiT2 is balanced by efflux through XPR1 (xenotropic and polytropic retrovirus receptor 1). Two new pathways for mammalian Pi transport regulation have been described recently: 1) in the presence of adequate Pi, cells continuously internalize and degrade PiT1. Pi starvation causes recycling of PiT1 from early endosomes to the plasma membrane and thereby increases the capacity for Pi influx; and 2) binding of inositol pyrophosphate InsP8 to the SPX domain of XPR1 increases Pi efflux. InsP8 is degraded by a phosphatase that is strongly inhibited by Pi. Therefore, an increase in [Pi]In decreases InsP8 degradation, increases InsP8 binding to SPX, and increases Pi efflux, completing a feedback loop for [Pi]In homeostasis. Published data on [Pi]In by magnetic resonance spectroscopy indicate that the steady state [Pi]In of skeletal muscle, heart, and brain is normally in the range of 1–5 mM, but it is not yet known whether PiT1 recycling or XPR1 activation by InsP8 contributes to Pi homeostasis in these organs. Data on [Pi]In in cultured cells are variable and suggest that some cells can regulate [Pi] better than others, following a change in [Pi]Ex. More measurements of [Pi]In, influx, and efflux are needed to determine how closely, and how rapidly, mammalian [Pi]In is regulated during either hyper- or hypophosphatemia.
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Rroji M, Figurek A, Viggiano D, Capasso G, Spasovski G. Phosphate in the Context of Cognitive Impairment and Other Neurological Disorders Occurrence in Chronic Kidney Disease. Int J Mol Sci 2022; 23:ijms23137362. [PMID: 35806367 PMCID: PMC9266940 DOI: 10.3390/ijms23137362] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/25/2022] [Accepted: 06/28/2022] [Indexed: 02/01/2023] Open
Abstract
The nervous system and the kidneys are linked under physiological states to maintain normal body homeostasis. In chronic kidney disease (CKD), damaged kidneys can impair the central nervous system, including cerebrovascular disease and cognitive impairment (CI). Recently, kidney disease has been proposed as a new modifiable risk factor for dementia. It is reported that uremic toxins may have direct neurotoxic (astrocyte activation and neuronal death) and/or indirect action through vascular effects (cerebral endothelial dysfunction, calcification, and inflammation). This review summarizes the evidence from research investigating the pathophysiological effects of phosphate toxicity in the nervous system, raising the question of whether the control of hyperphosphatemia in CKD would lower patients’ risk of developing cognitive impairment and dementia.
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Affiliation(s)
- Merita Rroji
- Department of Nephrology, Faculty of Medicine, University of Medicine Tirana, 1001 Tirana, Albania
- Correspondence:
| | - Andreja Figurek
- Department of Internal Medicine, Medical Faculty, University of Banja Luka, 78000 Banja Luka, Bosnia and Herzegovina;
- Institute of Anatomy, University of Zurich, 8057 Zurich, Switzerland
| | - Davide Viggiano
- Department of Translational Medical Sciences, University of Campania “L. Vanvitelli”, 80138 Naples, Italy; (D.V.); (G.C.)
- BioGeM, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Giovambattista Capasso
- Department of Translational Medical Sciences, University of Campania “L. Vanvitelli”, 80138 Naples, Italy; (D.V.); (G.C.)
- BioGeM, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Goce Spasovski
- University Clinic for Nephrology, Medical Faculty, University St. Cyril and Methodius, 1000 Skopje, North Macedonia;
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Razzaque MS. Salivary phosphate as a biomarker for human diseases. FASEB Bioadv 2022; 4:102-108. [PMID: 35141474 PMCID: PMC8814558 DOI: 10.1096/fba.2021-00104] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 12/20/2022] Open
Affiliation(s)
- Mohammed S. Razzaque
- Department of Pathology Lake Erie College of Osteopathic Medicine Erie Pennsylvania USA
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Phosphate and Endothelial Function: How Sensing of Elevated Inorganic Phosphate Concentration Generates Signals in Endothelial Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:85-98. [DOI: 10.1007/978-3-030-91623-7_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Alexander R, Debiec N, Razzaque MS, He P. Inorganic phosphate-induced cytotoxicity. IUBMB Life 2021; 74:117-124. [PMID: 34676972 DOI: 10.1002/iub.2561] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/27/2021] [Accepted: 09/18/2021] [Indexed: 12/17/2022]
Abstract
Phosphate, an essential nutrient, is available in organic and inorganic forms. The balance of phosphate is central for cellular homeostasis through the genomic roles of DNA and RNA synthesis and cell signaling processes. Therefore, an imbalance of this nutrient, manifested, either as a deficiency or excess in phosphate levels, can result in pathology, ranging from cytotoxicity to musculoskeletal defects. Inorganic phosphate (Pi) overdosing can result in a wide spectrum of cytotoxicity processes, as noted in both animal models and human studies. These include rewired cell signaling pathways, impaired bone mineralization, infertility, premature aging, vascular calcification, and renal dysfunction. This article briefly reviews the regulation of phosphate homeostasis and elaborates on cytotoxic effects of excessive Pi, as documented in cell-based models.
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Affiliation(s)
- Rachel Alexander
- Department of Biochemistry, Lake Erie College of Osteopathic Medicine, Erie, Pennsylvania, USA
| | - Nicholas Debiec
- Department of Biochemistry, Lake Erie College of Osteopathic Medicine, Erie, Pennsylvania, USA
| | - Mohammad S Razzaque
- Department of Pathology, Lake Erie College of Osteopathic Medicine, Erie, Pennsylvania, USA
| | - Ping He
- Department of Biochemistry, Lake Erie College of Osteopathic Medicine, Erie, Pennsylvania, USA
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Abbasian N. Vascular Calcification Mechanisms: Updates and Renewed Insight into Signaling Pathways Involved in High Phosphate-Mediated Vascular Smooth Muscle Cell Calcification. Biomedicines 2021; 9:804. [PMID: 34356868 PMCID: PMC8301440 DOI: 10.3390/biomedicines9070804] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/04/2021] [Accepted: 07/09/2021] [Indexed: 12/18/2022] Open
Abstract
Vascular calcification (VC) is associated with aging, cardiovascular and renal diseases and results in poor morbidity and increased mortality. VC occurs in patients with chronic kidney disease (CKD), a condition that is associated with high serum phosphate (Pi) and severe cardiovascular consequences. High serum Pi level is related to some pathologies which affect the behaviour of vascular cells, including platelets, endothelial cells (ECs) and smooth muscle cells (SMCs), and plays a central role in promoting VC. VC is a complex, active and cell-mediated process involving the transdifferentiation of vascular SMCs to a bone-like phenotype, systemic inflammation, decreased anti-calcific events (loss of calcification inhibitors), loss in SMC lineage markers and enhanced pro-calcific microRNAs (miRs), an increased intracellular calcium level, apoptosis, aberrant DNA damage response (DDR) and senescence of vascular SMCs. This review gives a brief overview of the current knowledge of VC mechanisms with a particular focus on Pi-induced changes in the vascular wall important in promoting calcification. In addition to reviewing the main findings, this review also sheds light on directions for future research in this area and discusses emerging pathways such as Pi-regulated intracellular calcium signaling, epigenetics, oxidative DNA damage and senescence-mediated mechanisms that may play critical, yet to be explored, regulatory and druggable roles in limiting VC.
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Affiliation(s)
- Nima Abbasian
- School of Life and Medical Sciences, University of Hertfordshire, Hertfordshire AL10 9AB, UK
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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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Abbasian N, Goodall AH, Burton JO, Bursnall D, Bevington A, Brunskill NJ. Hyperphosphatemia Drives Procoagulant Microvesicle Generation in the Rat Partial Nephrectomy Model of CKD. J Clin Med 2020; 9:jcm9113534. [PMID: 33139598 PMCID: PMC7692968 DOI: 10.3390/jcm9113534] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 12/11/2022] Open
Abstract
Hyperphosphatemia has been proposed as a cardiovascular risk factor, contributing to long-term vascular calcification in hyperphosphatemic Chronic Kidney Disease (CKD) patients. However, more recent studies have also demonstrated acute effects of inorganic phosphate (Pi) on endothelial cells in vitro, especially generation of pro-coagulant endothelial microvesicles (MV). Hitherto, such direct effects of hyperphosphatemia have not been reported in vivo. Thirty-six male Sprague-Dawley rats were randomly allocated to three experimental groups: (1) CKD induced by partial nephrectomy receiving high (1.2%) dietary phosphorus; (2) CKD receiving low (0.2%) dietary phosphorus; and (3) sham-operated controls receiving 1.2% phosphorus. After 14 days the animals were sacrificed and plasma MVs counted by nanoparticle tracking analysis. MVs isolated by centrifugation were assayed for pro-coagulant activity by calibrated automated thrombography, and relative content of endothelium-derived MVs was assessed by anti-CD144 immunoblotting. When compared with sham controls, high phosphorus CKD rats were shown to be hyperphosphatemic (4.11 ± 0.23 versus 2.41 ± 0.22 mM Pi, p < 0.0001) with elevated total plasma MVs (2.24 ± 0.37 versus 1.31 ± 0.24 × 108 per ml, p < 0.01), showing increased CD144 expression (145 ± 25% of control value, p < 0.0001), and enhanced procoagulant activity (18.06 ± 1.75 versus 4.99 ± 1.77 nM peak thrombin, p < 0.0001). These effects were abolished in the low phosphorus CKD group. In this rat model, hyperphosphatemia (or a Pi-dependent hormonal response derived from it) is sufficient to induce a marked increase in circulating pro-coagulant MVs, demonstrating an important link between hyperphosphatemia and thrombotic risk in CKD.
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Affiliation(s)
- Nima Abbasian
- Department of Cardiovascular Sciences, University of Leicester, and Leicester NIHR Cardiovascular Biomedical Research Unit, Leicester LE3 9QP, UK; (A.H.G.); (J.O.B.); (A.B.); (N.J.B.)
- Correspondence: ; Tel.: +44(0)122-384-0020
| | - Alison H. Goodall
- Department of Cardiovascular Sciences, University of Leicester, and Leicester NIHR Cardiovascular Biomedical Research Unit, Leicester LE3 9QP, UK; (A.H.G.); (J.O.B.); (A.B.); (N.J.B.)
| | - James O. Burton
- Department of Cardiovascular Sciences, University of Leicester, and Leicester NIHR Cardiovascular Biomedical Research Unit, Leicester LE3 9QP, UK; (A.H.G.); (J.O.B.); (A.B.); (N.J.B.)
- Department of Nephrology, Leicester General Hospital, Leicester LE5 4PW, UK
| | - Debbie Bursnall
- Division of Biomedical Services, University of Leicester, Leicester LE1 7RH, UK;
| | - Alan Bevington
- Department of Cardiovascular Sciences, University of Leicester, and Leicester NIHR Cardiovascular Biomedical Research Unit, Leicester LE3 9QP, UK; (A.H.G.); (J.O.B.); (A.B.); (N.J.B.)
| | - Nigel J. Brunskill
- Department of Cardiovascular Sciences, University of Leicester, and Leicester NIHR Cardiovascular Biomedical Research Unit, Leicester LE3 9QP, UK; (A.H.G.); (J.O.B.); (A.B.); (N.J.B.)
- Department of Nephrology, Leicester General Hospital, Leicester LE5 4PW, UK
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