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Walker V. The Intricacies of Renal Phosphate Reabsorption-An Overview. Int J Mol Sci 2024; 25:4684. [PMID: 38731904 PMCID: PMC11083860 DOI: 10.3390/ijms25094684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
To maintain an optimal body content of phosphorus throughout postnatal life, variable phosphate absorption from food must be finely matched with urinary excretion. This amazing feat is accomplished through synchronised phosphate transport by myriads of ciliated cells lining the renal proximal tubules. These respond in real time to changes in phosphate and composition of the renal filtrate and to hormonal instructions. How they do this has stimulated decades of research. New analytical techniques, coupled with incredible advances in computer technology, have opened new avenues for investigation at a sub-cellular level. There has been a surge of research into different aspects of the process. These have verified long-held beliefs and are also dramatically extending our vision of the intense, integrated, intracellular activity which mediates phosphate absorption. Already, some have indicated new approaches for pharmacological intervention to regulate phosphate in common conditions, including chronic renal failure and osteoporosis, as well as rare inherited biochemical disorders. It is a rapidly evolving field. The aim here is to provide an overview of our current knowledge, to show where it is leading, and where there are uncertainties. Hopefully, this will raise questions and stimulate new ideas for further research.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton S016 6YD, UK
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2
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Daryadel A, Haykir B, Küng CJ, Bugarski M, Bettoni C, Schnitzbauer U, Hernando N, Hall AM, Wagner CA. Acute adaptation of renal phosphate transporters in the murine kidney to oral phosphate intake requires multiple signals. Acta Physiol (Oxf) 2022; 235:e13815. [PMID: 35334154 DOI: 10.1111/apha.13815] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 12/01/2022]
Abstract
AIMS Dietary inorganic phosphate (Pi) modulates renal Pi reabsorption by regulating the expression of the NaPi-IIa and NaPi-IIc Pi transporters. Here, we aimed to clarify the role of several Pi-regulatory mechanisms including parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23) and inositol hexakisphosphate kinases (IP6-kinases) in the acute regulation of NaPi-IIa and NaPi-IIc. METHODS Wildtype (WT) and PTH-deficient mice (PTH-KO) with/without inhibition of FGF23 signalling were gavaged with Pi/saline and examined at 1, 4 and 12 h. RESULTS Pi-gavage elevated plasma Pi and decreased plasma Ca2+ in both genotypes after 1 h Within 1 h, Pi-gavage decreased NaPi-IIa abundance in WT and PTH-KO mice. NaPi-IIc was downregulated 1 h post-administration in WT and after 4 h in PTH-KO. PTH increased after 1 h in WT animals. After 4 h Pi-gavage, FGF23 increased in both genotypes being higher in the KO group. PTHrp and dopamine were not altered by Pi-gavage. Blocking FGF23 signalling blunted PTH upregulation in WT mice and reduced NaPi-IIa downregulation in PTH-KO mice 4 h after Pi-gavage. Inhibition of IP6-kinases had no effect. CONCLUSIONS (1) Acute downregulation of renal Pi transporters in response to Pi intake occurs also in the absence of PTH and FGF23 signalling, (2) when FGF23 signalling is blocked, a partial contribution of PTH is revealed, (3) IP6 kinases, intracellular Pi-sensors in yeast and bacteria, are not involved, and (4) Acute Pi does not alter PTHrp and dopamine. Thus, signals other than PTH, PTHrp, FGF23 and dopamine contribute to renal adaption.
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Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology University of Zürich Zürich Switzerland
- National Center of Competence in Research Kidney.CH Zürich Switzerland
| | - Betül Haykir
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | - Milica Bugarski
- National Center of Competence in Research Kidney.CH Zürich Switzerland
- Institute of Anatomy University of Zürich Zürich Switzerland
| | - Carla Bettoni
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | - Nati Hernando
- Institute of Physiology University of Zürich Zürich Switzerland
| | - Andrew M. Hall
- National Center of Competence in Research Kidney.CH Zürich Switzerland
- Institute of Anatomy University of Zürich Zürich Switzerland
| | - Carsten A. Wagner
- Institute of Physiology University of Zürich Zürich Switzerland
- National Center of Competence in Research Kidney.CH Zürich Switzerland
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Guo X, Jessel S, Qu R, Kluger Y, Chen TM, Hollander L, Safirstein R, Nelson B, Cha C, Bosenberg M, Jilaveanu LB, Rimm D, Rothlin CV, Kluger HM, Desir GV. Inhibition of renalase drives tumour rejection by promoting T cell activation. Eur J Cancer 2022; 165:81-96. [PMID: 35219026 PMCID: PMC8940682 DOI: 10.1016/j.ejca.2022.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 12/30/2021] [Accepted: 01/10/2022] [Indexed: 12/25/2022]
Abstract
BACKGROUND Although programmed cell death protein 1 (PD-1) inhibitors have revolutionised treatment for advanced melanoma, not all patients respond. We previously showed that inhibition of the flavoprotein renalase (RNLS) in preclinical melanoma models decreases tumour growth. We hypothesised that RNLS inhibition promotes tumour rejection by effects on the tumour microenvironment (TME). METHODS We used two distinct murine melanoma models, studied in RNLS knockout (KO) or wild-type (WT) mice. WT mice were treated with the anti-RNLS antibody, m28, with or without anti-PD-1. 10X single-cell RNA-sequencing was used to identify transcriptional differences between treatment groups, and tumour cell content was interrogated by flow cytometry. Samples from patients treated with immunotherapy were examined for RNLS expression by quantitative immunofluorescence. RESULTS RNLS KO mice injected with wild-type melanoma cells reject their tumours, supporting the importance of RNLS in cells in the TME. This effect was blunted by anti-cluster of differentiation 3. However, MØ-specific RNLS ablation was insufficient to abrogate tumour formation. Anti-RNLS antibody treatment of melanoma-bearing mice resulted in enhanced T cell infiltration and activation and resulted in immune memory on rechallenging mice with injection of melanoma cells. At the single-cell level, treatment with anti-RNLS antibodies resulted in increased tumour density of MØ, neutrophils and lymphocytes and increased expression of IFNγ and granzyme B in natural killer cells and T cells. Intratumoural Forkhead Box P3 + CD4 cells were decreased. In two distinct murine melanoma models, we showed that melanoma-bearing mice treated with anti-RNLS antibodies plus anti-PD-1 had superior tumour shrinkage and survival than with either treatment alone. Importantly, in pretreatment samples from patients treated with PD-1 inhibitors, high RNLS expression was associated with decreased survival (log-rank P = 0.006), independent of other prognostic variables. CONCLUSIONS RNLS KO results in melanoma tumour regression in a T-cell-dependent fashion. Anti-RNLS antibodies enhance anti-PD-1 activity in two distinct aggressive murine melanoma models resistant to PD-1 inhibitors, supporting the development of anti-RNLS antibodies with PD-1 inhibitors as a novel approach for melanomas poorly responsive to anti-PD-1.
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Affiliation(s)
- Xiaojia Guo
- Department of Medicine Section of Nephrology, Yale University, New Haven, CT, USA
| | - Shlomit Jessel
- Department of Medicine Section of Medical Oncology, Yale University, New Haven, CT, USA
| | - Rihao Qu
- Department of Medicine Pathology, Yale University, New Haven, CT, USA
| | - Yuval Kluger
- Department of Medicine Pathology, Yale University, New Haven, CT, USA
| | - Tian-Min Chen
- Department of Medicine Section of Nephrology, Yale University, New Haven, CT, USA
| | - Lindsay Hollander
- Department of Medicine Section of Nephrology, Yale University, New Haven, CT, USA
| | - Robert Safirstein
- Department of Medicine Section of Nephrology, Yale University, New Haven, CT, USA; Department of Medicine VACHS, Yale University, New Haven, CT, USA
| | - Bryce Nelson
- Department of Medicine Pharmacology, Yale University, New Haven, CT, USA
| | - Charles Cha
- Department of Medicine Surgery, Yale University, New Haven, CT, USA
| | - Marcus Bosenberg
- Department of Medicine Section of Medical Oncology, Yale University, New Haven, CT, USA
| | - Lucia B Jilaveanu
- Department of Medicine Section of Medical Oncology, Yale University, New Haven, CT, USA
| | - David Rimm
- Department of Medicine Pathology, Yale University, New Haven, CT, USA
| | - Carla V Rothlin
- Department of Medicine Immunology, Yale University, New Haven, CT, USA
| | - Harriet M Kluger
- Department of Medicine Section of Medical Oncology, Yale University, New Haven, CT, USA
| | - Gary V Desir
- Department of Medicine Section of Nephrology, Yale University, New Haven, CT, USA; Department of Medicine VACHS, Yale University, New Haven, CT, USA; Department of Medicine Yale School of Medicine, Yale University, New Haven, CT, USA.
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4
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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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Matt SM, Gaskill PJ. Where Is Dopamine and how do Immune Cells See it?: Dopamine-Mediated Immune Cell Function in Health and Disease. J Neuroimmune Pharmacol 2020; 15:114-164. [PMID: 31077015 PMCID: PMC6842680 DOI: 10.1007/s11481-019-09851-4] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/07/2019] [Indexed: 02/07/2023]
Abstract
Dopamine is well recognized as a neurotransmitter in the brain, and regulates critical functions in a variety of peripheral systems. Growing research has also shown that dopamine acts as an important regulator of immune function. Many immune cells express dopamine receptors and other dopamine related proteins, enabling them to actively respond to dopamine and suggesting that dopaminergic immunoregulation is an important part of proper immune function. A detailed understanding of the physiological concentrations of dopamine in specific regions of the human body, particularly in peripheral systems, is critical to the development of hypotheses and experiments examining the effects of physiologically relevant dopamine concentrations on immune cells. Unfortunately, the dopamine concentrations to which these immune cells would be exposed in different anatomical regions are not clear. To address this issue, this comprehensive review details the current information regarding concentrations of dopamine found in both the central nervous system and in many regions of the periphery. In addition, we discuss the immune cells present in each region, and how these could interact with dopamine in each compartment described. Finally, the review briefly addresses how changes in these dopamine concentrations could influence immune cell dysfunction in several disease states including Parkinson's disease, multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, as well as the collection of pathologies, cognitive and motor symptoms associated with HIV infection in the central nervous system, known as NeuroHIV. These data will improve our understanding of the interactions between the dopaminergic and immune systems during both homeostatic function and in disease, clarify the effects of existing dopaminergic drugs and promote the creation of new therapeutic strategies based on manipulating immune function through dopaminergic signaling. Graphical Abstract.
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Affiliation(s)
- S M Matt
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - P J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, 19102, USA.
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6
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Chang J, Guo X, Rao V, Gromisch E, Chung S, Kluger H, Cha C, Gorelick F, Testani J, Safirstein R, Crowley S, Peixoto A, Desir G. Identification of Two Forms of Human Plasma Renalase, and Their Association With All-Cause Mortality. Kidney Int Rep 2020; 5:362-368. [PMID: 32154458 PMCID: PMC7056858 DOI: 10.1016/j.ekir.2019.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/15/2019] [Accepted: 12/06/2019] [Indexed: 01/13/2023] Open
Affiliation(s)
- J. Chang
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Veterans Affairs Connecticut Health System, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - X. Guo
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - V. Rao
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - E.S. Gromisch
- Veterans Affairs Connecticut Health System, University of Connecticut School of Medicine, Farmington, Connecticut, USA
- Department of Neurology, University of Connecticut School of Medicine, Farmington, Connecticut, USA
- Mandell Center for Multiple Sclerosis, Mount Sinai Rehabilitation Hospital, Trinity Health of New England, Hartford, Connecticut, USA
- Department of Rehabilitative Medicine, Frank H. Netter MD School of Medicine, Quinnipiac University, North Haven, Connecticut, USA
- Department of Medical Sciences, Frank H. Netter MD School of Medicine, Quinnipiac University, North Haven, Connecticut, USA
| | - S. Chung
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - H.M. Kluger
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Section of Medical Oncology, Yale School of Medicine, New Haven, Connecticut, USA
| | - C. Cha
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Surgery, Yale School of Medicine, New Haven, Connecticut, USA
| | - F. Gorelick
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Veterans Affairs Connecticut Health System, University of Connecticut School of Medicine, Farmington, Connecticut, USA
- Department of Cell Biology, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - J. Testani
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - R. Safirstein
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Veterans Affairs Connecticut Health System, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - S. Crowley
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Veterans Affairs Connecticut Health System, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - A.J. Peixoto
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - G.V. Desir
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
- Veterans Affairs Connecticut Health System, University of Connecticut School of Medicine, Farmington, Connecticut, USA
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The Relationship between Sleep Bruxism Intensity and Renalase Concentration-An Enzyme Involved in Hypertension Development. J Clin Med 2019; 9:jcm9010016. [PMID: 31861602 PMCID: PMC7019696 DOI: 10.3390/jcm9010016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 11/21/2022] Open
Abstract
Background and objectives: Renalase, a novel amine oxidase, is involved in the development of hypertension. Sleep bruxism (SB) is a sleep-related behavior characterized by rhythmic or non-rhythmic activity of the masticatory muscles, which leads to the mechanical wear of teeth, pain in the masticatory muscles, and disturbed sleep. Recent studies indicate that SB plays a role in increased blood pressure. Therefore, this study aimed to determine the relationship between sleep bruxism intensity and renalase concentration, which may help in the future to elucidate the pathogenesis of hypertension and other cardiovascular disorders. Material and methods: SB was evaluated in 87 adult patients using single-night diagnostic polysomnography with video and audio recordings, and the episodes of bruxism were scored according to the standards of the American Academy of Sleep Medicine. The levels of serum renalase were measured in the patients using enzyme-linked immunosorbent assay kits. Results: SB (Bruxism Episode Index (BEI) ≥2) was diagnosed in 54% (n = 47) of the studied population, and the mean concentration of renalase was found to be decreased in the hypertensive group compared with the normotensive group (133.33 ± 160.71 vs 219.23 ± 220.58, p = 0.047). In addition, a linear negative correlation was observed between the renalase concentration and the body mass index (BMI) in the SB group (r = 0.38, p < 0.05) but not in controls. Thus, higher BEI and higher BMI were identified as factors independently associated with the lower concentration of renalase, but only in the group of patients which had a blood renalase concentration of >212.5 ng/mL. Conclusion: There exists an association between renalase concentration and SB intensity, and further studies are needed to clarify the role of renalase in the pathogenesis of hypertension and other cardiovascular disorders.
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Abstract
Calcium kidney stones are common worldwide. Most are idiopathic and composed of calcium oxalate. Calcium phosphate is present in around 80% and may initiate stone formation. Stone production is multifactorial with a polygenic genetic contribution. Phosphaturia is found frequently among stone formers but until recently received scant attention. This review examines possible mechanisms for the phosphaturia and its relevance to stone formation from a wide angle. There is a striking lack of clinical data. Phosphaturia is associated, but not correlated, with hypercalciuria, increased 1,25 dihydroxy-vitamin D [1,25 (OH)2D], and sometimes evidence of disturbances in proximal renal tubular function. Phosphate reabsorption in the proximal renal tubules requires tightly regulated interaction of many proteins. Paracellular flow through intercellular tight junctions is the major route of phosphate absorption from the intestine and can be reduced therapeutically in hyperphosphatemic patients. In monogenic defects stones develop when phosphaturia is associated with hypercalciuria, generally explained by increased 1,25 (OH)2D production in response to hypophosphatemia. Calcification does not occur in disorders with increased FGF23 when phosphaturia occurs in isolation and 1,25 (OH)2D is suppressed. Candidate gene studies have identified mutations in the phosphate transporters, but in few individuals. One genome-wide study identified a polymorphism of the phosphate transporter gene SLC34A4 associated with stones. Others did not find mutations obviously linked to phosphate reabsorption. Future genetic studies should have a wide trawl and should focus initially on groups of patients with clearly defined phenotypes. The global data should be pooled.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
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9
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Abstract
Although phosphorus is an essential nutrient required for multiple physiological functions, recent research raises concerns that high phosphorus intake could have detrimental effects on health. Phosphorus is abundant in the food supply of developed countries, occurring naturally in protein-rich foods and as an additive in processed foods. High phosphorus intake can cause vascular and renal calcification, renal tubular injury, and premature death in multiple animal models. Small studies in human suggest that high phosphorus intake may result in positive phosphorus balance and correlate with renal calcification and albuminuria. Although serum phosphorus is strongly associated with cardiovascular disease, progression of kidney disease, and death, limited data exist linking high phosphorus intake directly to adverse clinical outcomes. Further prospective studies are needed to determine whether phosphorus intake is a modifiable risk factor for kidney disease.
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Affiliation(s)
- Alex R Chang
- Kidney Health Research Institute, Geisinger Health System, Danville, Pennsylvania 17822; .,Department of Epidemiology and Health Services Research, Geisinger Health System, Geisinger Health System, Danville, Pennsylvania 17822
| | - Cheryl Anderson
- Division of Preventive Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
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10
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Wang Y, Safirstein R, Velazquez H, Guo XJ, Hollander L, Chang J, Chen TM, Mu JJ, Desir GV. Extracellular renalase protects cells and organs by outside-in signalling. J Cell Mol Med 2017; 21:1260-1265. [PMID: 28238213 PMCID: PMC5487909 DOI: 10.1111/jcmm.13062] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/18/2016] [Indexed: 01/07/2023] Open
Abstract
Renalase was discovered as a protein synthesized by the kidney and secreted in blood where it circulates at a concentration of approximately 3-5 μg/ml. Initial reports suggested that it functioned as an NAD(P)H oxidase and could oxidize catecholamines. Administration of renalase lowers blood pressure and heart rate and also protects cells and organs against ischaemic and toxic injury. Although renalase's protective effect was initially ascribed to its oxidase properties, a paradigm shift in our understanding of the cellular actions of renalase is underway. We now understand that, independent of its enzymatic properties, renalase functions as a cytokine that provides protection to cells, tissues and organs by interacting with its receptor to activate protein kinase B, JAK/STAT, and the mitogen-activated protein kinase pathways. In addition, recent studies suggest that dysregulated renalase signalling may promote survival of several tumour cells due to its capacity to augment expression of growth-related genes. In this review, we focus on the cytoprotective actions of renalase and its capacity to sustain cancer cell growth and also the translational opportunities these findings represent for the development of novel therapeutic strategies for organ injury and cancer.
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Affiliation(s)
- Yang Wang
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA.,Department of Cardiology, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, China
| | - Robert Safirstein
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA
| | - Heino Velazquez
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA
| | - Xiao-Jia Guo
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA
| | - Lindsay Hollander
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA.,Department of Surgery, University of Connecticut, Farmington, CT, USA
| | - John Chang
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA
| | - Tian-Min Chen
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA
| | - Jian-Jun Mu
- Department of Cardiology, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, China
| | - Gary V Desir
- Department of Medicine, Veterans Affairs Connecticut Healthcare System, Yale University, New Haven, CT, USA
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11
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Thomas L, Bettoni C, Knöpfel T, Hernando N, Biber J, Wagner CA. Acute Adaption to Oral or Intravenous Phosphate Requires Parathyroid Hormone. J Am Soc Nephrol 2016; 28:903-914. [PMID: 28246304 DOI: 10.1681/asn.2016010082] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 08/22/2016] [Indexed: 12/17/2022] Open
Abstract
Phosphate (Pi) homeostasis is regulated by renal, intestinal, and endocrine mechanisms through which Pi intake stimulates parathyroid hormone (PTH) and fibroblast growth factor-23 secretion, increasing phosphaturia. Mechanisms underlying the early adaptive phase and the role of the intestine, however, remain ill defined. We investigated mineral, endocrine, and renal responses during the first 4 hours after intravenous and intragastric Pi loading in rats. Intravenous Pi loading (0.5 mmol) caused a transient rise in plasma Pi levels and creatinine clearance and an increase in phosphaturia within 10 minutes. Plasma calcium levels fell and PTH levels increased within 10 minutes and remained low or high, respectively. Fibroblast growth factor-23, 1,25-(OH)2-vitamin D3, and insulin concentrations did not respond, but plasma dopamine levels increased by 4 hours. In comparison, gastric Pi loading elicited similar but delayed phosphaturia and endocrine responses but did not affect plasma mineral levels. Either intravenous or gastric loading led to decreased expression and activity of renal Pi transporters after 4 hours. In parathyroidectomized rats, however, only intravenous Pi loading caused phosphaturia, which was blunted and transient compared with that in intact rats. Intravenous but not gastric Pi loading in parathyroidectomized rats also led to higher creatinine clearance and lower plasma calcium levels but did not reduce the expression or activity of Pi transporters. This evidence suggests that an intravenous or intestinal Pi bolus causes rapid phosphaturia through mechanisms requiring PTH and downregulation of renal Pi transporters but does not support a role of the intestine in stimulating renal clearance of Pi.
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Affiliation(s)
- Linto Thomas
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Thomas Knöpfel
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Jürg Biber
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
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12
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Renalase: its role as a cytokine, and an update on its association with type 1 diabetes and ischemic stroke. Curr Opin Nephrol Hypertens 2015; 23:513-8. [PMID: 24992568 DOI: 10.1097/mnh.0000000000000044] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE OF REVIEW Remarkable progress has been achieved over the past 2 years in understanding the cellular actions of renalase, its pathophysiology and potential therapeutic utility. RECENT FINDINGS There has been a paradigm shift in our thinking about the mechanisms underlying the cellular actions of renalase. We now understand that, independent of its enzymatic properties, renalase functions as a signaling molecule, a cytokine that interacts with a yet-to-be identified plasma membrane receptor(s) to activate protein kinase B and the mitogen-activated protein kinase pathway. These signaling properties are critical to its cytoprotective effects. New information regarding renalase's enzymatic function as an α-nicotinamide adenine dinucleotide oxidase/anomerase will be reviewed. Lastly, we will discuss the association of certain single nucleotide polymorphisms in the renalase gene with type 1 diabetes and with ischemic stroke, and the clinical implications of these findings. SUMMARY The consistent association of renalase single nucleotide polymorphisms and the development of type 1 diabetes is a great interest particularly because we now understand that renalase functions as a cytokine. Future work on renalase should focus on exploring the identity of its receptor(s), and its potential role as an immune modulator.
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13
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Malyszko J, Bachorzewska-Gajewska H, Dobrzycki S. Renalase, kidney and cardiovascular disease: are they related or just coincidentally associated? Adv Med Sci 2015; 60:41-9. [PMID: 25461379 DOI: 10.1016/j.advms.2014.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/15/2014] [Accepted: 10/10/2014] [Indexed: 12/15/2022]
Abstract
Cardiovascular diseases, including hypertension are the leading cause of death in the developed countries. Diabetes and chronic kidney disease became also more prevalent reaching almost the level of epidemy. Researchers are looking eagerly for the new risk and/or pathogenetic factors, as well as therapeutic option in these disease. It has been suggested that human kidney releases a protein named renalase into the bloodstream. It is supposed to be an enzyme which breaks down catecholamines in the blood circulation and regulate blood pressure. However, there were several doubts whether renalase exerts monoaminooxidase activity, or if it is monoaminooxidase at all. Recently, a hypothesis that it is also a cytokine was postulated. Studies on renalase polymorphisms in hypertension, cardiovascular disease or diabetes are inconsistent. Similarly, there are several discrepancies in the animal on the possible role of renalase in hypertension and cardiovascular diseases. Some studies report a protective role of renalase in acute kidney injury, whereas others showed that renalase levels were mainly dependent on kidney function, indicating rather a role of kidney in excretion of this substance. Moreover, validated assays are needed to evaluate renalase levels and activity. On one hand a deeper and more accurate link between renalase and cardiovascular diseases require further profound research, on the other hand whether or not renalase protein could be a new therapeutic target in these pathologies should also be considered. Whether renalase, discovered in 2005, might be a Holy Grail of hypertension, linking kidney and cardiovascular diseases, remains to be proven.
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Affiliation(s)
- Jolanta Malyszko
- 2nd Department of Nephrology and Hypertension with Dialysis Unit, Medical University of Bialystok, Bialystok, Poland.
| | | | - Slawomir Dobrzycki
- Invasive Cardiology Department, Medical University of Bialystok, Bialystok, Poland
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Abstract
Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.
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Affiliation(s)
- P Manghat
- Department of Chemical Pathology, Darent Valley Hospital, Dartford, UK
| | - R Sodi
- Department of Biochemistry, NHS Lanarkshire, East Kilbride, UK
| | - R Swaminathan
- Department of Chemical Pathology, St. Thomas Hospital, London, UK
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15
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Li X, Huang R, Xie Z, Lin M, Liang Z, Yang Y, Jiang W. Renalase, a new secretory enzyme: Its role in hypertensive-ischemic cardiovascular diseases. Med Sci Monit 2014; 20:688-92. [PMID: 24762661 PMCID: PMC4005863 DOI: 10.12659/msm.890261] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Abstract Renalase, a novel amine oxidase, is mainly expressed in the kidney, heart, and skeletal muscle. It has been known to degrade circulating catecholamines and plays a crucial role in human diseases. Recent studies have demonstrated its structure, unique bioactivities, function, and the gene polymorphisms in human diseases. In this review, we summarize the effects of renalase on hypertension, myocardial ischemia, acute kidney injury (AKI), ischemic stroke, cardiac dysfunction, organ transplantation, and diabetes mellitus reported in numerous studies.
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Affiliation(s)
- Xiaogang Li
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China (mainland)
| | - Ruixia Huang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China (mainland)
| | - Zijian Xie
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China (mainland)
| | - Mingyuan Lin
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China (mainland)
| | - Zhongshu Liang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China (mainland)
| | - Yan Yang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China (mainland)
| | - Weihong Jiang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China (mainland)
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16
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Wang F, Huang B, Li J, Liu L, Wang N. Renalase might be associated with hypertension and insulin resistance in Type 2 diabetes. Ren Fail 2014; 36:552-6. [DOI: 10.3109/0886022x.2013.876352] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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17
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Biber J, Murer H, Mohebbi N, Wagner C. Renal Handling of Phosphate and Sulfate. Compr Physiol 2014; 4:771-92. [DOI: 10.1002/cphy.c120031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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18
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Serum renalase is related to catecholamine levels and renal function. Clin Exp Nephrol 2014; 19:92-8. [DOI: 10.1007/s10157-014-0951-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/14/2014] [Indexed: 01/07/2023]
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19
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Wang S, Lu X, Yang J, Wang H, Chen C, Han Y, Ren H, Zheng S, He D, Zhou L, Asico LD, Wang WE, Jose PA, Zeng C. Regulation of renalase expression by D5 dopamine receptors in rat renal proximal tubule cells. Am J Physiol Renal Physiol 2014; 306:F588-96. [PMID: 24500688 DOI: 10.1152/ajprenal.00196.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The dopaminergic and sympathetic systems interact to regulate blood pressure. Our previous studies showed regulation of α1-adrenergic receptor function by D1-like dopamine receptors in vascular smooth muscle cells. Because renalase could regulate circulating epinephrine levels and dopamine production in renal proximal tubules (RPTs), we tested the hypothesis that D1-like receptors regulate renalase expression in kidney. The effect of D1-like receptor stimulation on renalase expression and function was measured in immortalized RPT cells from Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHRs). We found that the D1-like receptor agonist fenoldopam (10(-7)-10(-5) mol/l) increased renalase protein expression and function in WKY RPT cells but decreased them in SHR cells. Fenoldopam also increased renalase mRNA levels in WKY but not in SHR cells. In contrast, fenoldopam increased the degradation of renalase protein in SHR cells but not in WKY cells. The regulation of renalase by the D1-like receptor was mainly via the D5 receptor because silencing of the D5 but not D1 receptor by antisense oligonucleotides blocked the stimulatory effect of the D1-like receptor on renalase expression in WKY cells. Moreover, inhibition of PKC, by the PKC inhibitor 19-31, blocked the stimulatory effect of fenoldopam on renalase expression while stimulation of PKC, by a PKC agonist (PMA), increased renalase expression, indicating that PKC is involved in the process. Our studies suggest that the D5 receptor positively regulates renalase expression in WKY but not SHR RPT cells; aberrant regulation of renalase by the D5 receptor may be involved in the pathogenesis of hypertension.
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Affiliation(s)
- Shaoxiong Wang
- Dept. of Cardiology, Daping Hospital, The Third Military Medical Univ., Chongqing, P.R. China.
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Abstract
Renalase, a recently discovered flavoprotein, which is strongly expressed in the kidney and heart, effectively metabolizes catecholamines. It was discovered during the search to identify proteins secreted by the kidney that could help explain the high incidence of cardiovascular disease in patients with chronic kidney disease. Recent advances have led to more detailed knowledge of its biology, structure, enzymatic activity, mechanisms of action, associations with human disease states and potential therapeutic value. In this study, we review these advances with a focus on hypertension and kidney disease.
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Affiliation(s)
- Gary V Desir
- Medical Service, VA Connecticut Healthcare System, West Haven, CT, USA
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Sizova D, Velazquez H, Sampaio-Maia B, Quelhas-Santos J, Pestana M, Desir GV. Renalase regulates renal dopamine and phosphate metabolism. Am J Physiol Renal Physiol 2013; 305:F839-44. [PMID: 23863468 DOI: 10.1152/ajprenal.00616.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Renalase is a kidney-secreted catecholamines-degrading enzyme whose expression and activity are downregulated by increased dietary phosphate. A renalase knockout (KO) mouse model was used to explore the mechanisms mediating renalase's effect on phosphate excretion. Compared with wild-type (WT) mice maintained on a regular diet, KO mice show decreased serum PO4(-) (KO = 5.3 ± 0.2 vs. WT = 6.0 ± 0.1, n = 6; P < 0.04) and increased urinary PO4(-) excretion (urine PO4(-)/creatinine: KO = 7.7 ± 0.3 vs. WT = 6.1 ± 0.3, n = 6; P < 0.02). However, both WT and KO mice respond similarly to PO4(-) restriction by increasing renal COMT-1 activity and markedly decreasing PO4(-) excretion, which excludes an intrinsic renal defect in the KO. Renal sodium-phosphate cotransporter Npt2a, sodium proton exchanger NHE3 expression, and MAO-A and B activity did not differ between WT and KO. Only catechol-O-methyl transferase (COMT) expression and activity were significantly increased in KO mice. Despite that, urinary dopamine increased by twofold, whereas urinary l-DOPA excretion decreased by twofold in the KO mouse, indicating an upregulation of renal dopamine (DA) synthesis. These data indicate that renalase deficiency is associated with increased renal DA synthesis, stimulated PO4(-) excretion, and moderately severe hypophosphatemia. The signal to increase renal DA synthesis is strong since it overcomes a compensatory increase in COMT activity.
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Affiliation(s)
- Daria Sizova
- Section of Nephrology, Dept. of Medicine, Yale School of Medicine, P.O. Box 208029, New Haven, CT 06520-8029.
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The phosphate transporter NaPi-IIa determines the rapid renal adaptation to dietary phosphate intake in mouse irrespective of persistently high FGF23 levels. Pflugers Arch 2013; 465:1557-72. [PMID: 23708836 DOI: 10.1007/s00424-013-1298-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 05/03/2013] [Accepted: 05/13/2013] [Indexed: 01/13/2023]
Abstract
Renal reabsorption of inorganic phosphate (Pi) is mediated by the phosphate transporters NaPi-IIa, NaPi-IIc, and Pit-2 in the proximal tubule brush border membrane (BBM). Dietary Pi intake regulates these transporters; however, the contribution of the specific isoforms to the rapid and slow phase is not fully clarified. Moreover, the regulation of PTH and FGF23, two major phosphaturic hormones, during the adaptive phase has not been correlated. C57/BL6 and NaPi-IIa(-/-) mice received 5 days either 1.2 % (HPD) or 0.1 % (LPD) Pi-containing diets. Thereafter, some mice were acutely switched to LPD or HPD. Plasma Pi concentrations were similar under chronic diets, but lower when mice were acutely switched to LPD. Urinary Pi excretion was similar in C57/BL6 and NaPi-IIa(-/-) mice under HPD. During chronic LPD, NaPi-IIa(-/-) mice lost phosphate in urine compensated by higher intestinal Pi absorption. During the acute HPD-to-LPD switch, NaPi-IIa(-/-) mice exhibited a delayed decrease in urinary Pi excretion. PTH was acutely regulated by low dietary Pi intake. FGF23 did not respond to low Pi intake within 8 h whereas the phospho-adaptator protein FRS2α necessary for FGF-receptor cell signaling was downregulated. BBM Pi transport activity and NaPi-IIa but not NaPi-IIc and Pit-2 abundance acutely adapted to diets in C57/BL6 mice. In NaPi-IIa(-/-), Pi transport activity was low and did not adapt. Thus, NaPi-IIa mediates the fast adaptation to Pi intake and is upregulated during the adaptation to low Pi despite persistently high FGF23 levels. The sensitivity to FGF23 may be regulated by adapting FRS2α abundance and phosphorylation.
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Deftereos SN, Dodou E, Andronis C, Persidis A. From depression to neurodegeneration and heart failure: re-examining the potential of MAO inhibitors. Expert Rev Clin Pharmacol 2013; 5:413-25. [PMID: 22943121 DOI: 10.1586/ecp.12.29] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Initially introduced in the 1950s for treating depression, monoamine oxidase (MAO) inhibitors were gradually abandoned, mainly owing to their potential for drug-drug and drug-food interactions, the most widely known being with tyramine-containing food (the 'cheese' effect). Since then, more selective MAO-A or MAO-B inhibitors have been developed with substantially reduced risks, and have been approved for the treatment of depression and Parkinson's disease, respectively. Recent research suggests that some of these drugs also have neuroprotective properties, while preclinical evidence expands the spectrum of potential indications to heart failure, renal diseases and multiple sclerosis. In this article, the authors review the relevance of MAO isoforms to disease, and they also outline current research and development efforts in this class of drugs, including newer multipotent compounds.
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Desir GV, Wang L, Peixoto AJ. Human renalase: a review of its biology, function, and implications for hypertension. ACTA ACUST UNITED AC 2012; 6:417-26. [DOI: 10.1016/j.jash.2012.09.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 09/18/2012] [Indexed: 02/04/2023]
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Wang F, Xing T, Li J, Bai M, Hu R, Zhao Z, Tian S, Zhang Z, Wang N. Renalase's expression and distribution in renal tissue and cells. PLoS One 2012; 7:e46442. [PMID: 23056310 PMCID: PMC3463591 DOI: 10.1371/journal.pone.0046442] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 08/30/2012] [Indexed: 12/19/2022] Open
Abstract
To study renalase's expression and distribution in renal tissues and cells, renalase coded DNA vaccine was constructed, and anti-renalase monoclonal antibodies were produced using DNA immunization and hybridoma technique, followed by further investigation with immunological testing and western blotting to detect the expression and distribution of renalase among the renal tissue and cells. Anti-renalase monoclonal antibodies were successfully prepared by using DNA immunization technique. Further studies with anti-renalase monoclonal antibody showed that renalase expressed in glomeruli, tubule, mesangial cells, podocytes, renal tubule epithelial cells and its cells supernatant. Renalase is wildly expressed in kidney, including glomeruli, tubule, mesangial cells, podocytes and tubule epithelial cells, and may be secreted by tubule epithelial cells primarily.
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Affiliation(s)
- Feng Wang
- Department of Nephrology and Rheumatology, Shanghai Sixth People's Hospital affiliated to Shanghai Jiaotong University, Shanghai, China
- * E-mail: (FW); (NW)
| | - Tao Xing
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
| | - Junhui Li
- Department of Nephrology and Rheumatology, Shanghai Sixth People's Hospital affiliated to Shanghai Jiaotong University, Shanghai, China
| | - Mei Bai
- Department of Nephrology and Rheumatology, Shanghai Sixth People's Hospital affiliated to Shanghai Jiaotong University, Shanghai, China
| | - Ruimin Hu
- Department of Pathology, Shanghai Medical College, Fudan Univesity, Shanghai, China
| | - Zhonghua Zhao
- Department of Pathology, Shanghai Medical College, Fudan Univesity, Shanghai, China
| | - Shoufu Tian
- Department of Nephrology and Rheumatology, Shanghai Sixth People's Hospital affiliated to Shanghai Jiaotong University, Shanghai, China
| | - Zhigang Zhang
- Department of Pathology, Shanghai Medical College, Fudan Univesity, Shanghai, China
| | - Niansong Wang
- Department of Nephrology and Rheumatology, Shanghai Sixth People's Hospital affiliated to Shanghai Jiaotong University, Shanghai, China
- * E-mail: (FW); (NW)
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Malyszko J, Malyszko JS, Rysz J, Mysliwiec M, Tesar V, Levin-Iaina N, Banach M. Renalase, hypertension, and kidney - the discussion continues. Angiology 2012; 64:181-7. [PMID: 22969162 DOI: 10.1177/0003319712459212] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hypertension and cardiovascular complications are very common in chronic kidney disease (CKD). Overactivation of sympathetic nervous system is also widely recognized in CKD. Renalase may play an important role in the control of blood pressure (BP) by its regulatory function of catecholamine metabolism. Renalase could be synthesized not only by the kidney but also by cardiomyocytes, liver, and adipose tissue. It probably exerts a hypotensive action, at least in animal models. Whether it metabolizes catecholamines remains to be proved. Another issue that remains to be resolved is the relationship between renalase and renal natriuresis and phosphaturia. In this review, the updated experimental and clinical data on renalase are presented and possible interactions with the endothelium are discussed. Renalase is "a new postulated therapeutic target." Proof of concept studies are needed to define the pathophysiological link between the kidney, sympathetic tone, BP, and cardiovascular complications.
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Affiliation(s)
- Jolanta Malyszko
- Department of Nephrology and Transplantology, Medical University in Bialystok, Bialystok, Poland.
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Bansal N, Hsu CY, Whooley M, Berg AH, Ix JH. Relationship of urine dopamine with phosphorus homeostasis in humans: the heart and soul study. Am J Nephrol 2012; 35:483-90. [PMID: 22572568 DOI: 10.1159/000338483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/29/2012] [Indexed: 12/17/2022]
Abstract
BACKGROUND Urine dopamine (DA) is produced in the proximal tubule and has been found to increase in response to dietary phosphorus intake, and to contribute to greater urinary phosphorus excretion in animal models. Whether urine DA is associated with phosphorus homeostasis in humans is uncertain. METHODS This was a cross-sectional study of 884 outpatients. DA was measured from 24-hour urine collections. We examined cross-sectional associations between urine DA and serum phosphorus, 24-hour urine phosphorus (as an indicator of dietary phosphorus absorption), fractional excretion of phosphorus (FEphos), fibroblast growth factor (FGF)-23, and parathyroid hormone (PTH). Models were adjusted for age, sex, race, eGFR, albuminuria, hypertension, heart failure, tobacco use, body mass index, and diuretic use. RESULTS Mean age was 66.6 ± 11 years and mean eGFR was 71 ± 21.3 ml/min/1.73 m(2). The mean urine DA was 193 ± 86 µg/day, mean serum phosphorus was 3.6 ± 0.6 mg/dl, mean daily urine phosphorus excretion was 671 ± 312 mg/day, and mean FEphos was 17 ± 9%. In adjusted models, each standard deviation higher DA was associated with 78.4 mg/day higher urine phosphorus and 0.9% lower FEphos (p < 0.05 for both). There was no statistically significant association between urine DA, serum phosphorus, FGF-23 or PTH in adjusted models. CONCLUSIONS Higher dietary phosphorus absorption is associated with higher urine DA in humans, consistent with animal models. However, higher urine DA is not associated with FGF-23 or PTH, suggesting that known mechanisms of renal tubular handling of phosphorus may not be involved in the renal dopamine-phosphorus regulatory pathway in humans.
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Affiliation(s)
- Nisha Bansal
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
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28
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Weinman EJ, Lederer ED. NHERF-1 and the regulation of renal phosphate reabsoption: a tale of three hormones. Am J Physiol Renal Physiol 2012; 303:F321-7. [PMID: 22535796 DOI: 10.1152/ajprenal.00093.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The renal excretion of inorganic phosphate is regulated in large measure by three hormones, namely, parathyroid hormone, dopamine, and fibroblast growth factor-23. Recent experiments have indicated that the major sodium-dependent phosphate transporter in the renal proximal tubule, Npt2a, binds to the adaptor protein sodium-hydrogen exchanger regulatory factor-1 (NHERF-1) and in the absence of NHERF-1, the inhibitory effect of these three hormones is absent. From these observations, a new model for the hormonal regulation of renal phosphate transport was developed. The downstream signaling pathways of these hormones results in the phosphorylation of the PDZ 1 domain of NHERF-1 and the dissociation of Npt2a/NHERF-1 complexes. In turn, this dissociation facilitates the endocytosis of Npt2a with a subsequent decrease in the apical membrane abundance of the transporter and a decrease in phosphate reabsorption. The current review outlines the experimental observations supporting the operation of this unique regulatory system.
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Affiliation(s)
- Edward J Weinman
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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FAD-binding site and NADP reactivity in human renalase: a new enzyme involved in blood pressure regulation. J Mol Biol 2011; 411:463-73. [PMID: 21699903 DOI: 10.1016/j.jmb.2011.06.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 06/06/2011] [Accepted: 06/07/2011] [Indexed: 01/05/2023]
Abstract
Renalase is a recently discovered flavoprotein that regulates blood pressure, regulates sodium and phosphate excretion, and displays cardioprotectant action through a mechanism that is barely understood to date. It has been proposed to act as a catecholamine-degrading enzyme, via either O(2)-dependent or NADH-dependent mechanisms. Here we report the renalase crystal structure at 2.5 Å resolution together with new data on its interaction with nicotinamide dinucleotides. Renalase adopts the p-hydroxybenzoate hydroxylase fold topology, comprising a Rossmann-fold-based flavin adenine dinucleotide (FAD)-binding domain and a putative substrate-binding domain, the latter of which contains a five-stranded anti-parallel β-sheet. A large cavity (228 Å(3)), facing the flavin ring, presumably represents the active site. Compared to monoamine oxidase or polyamine oxidase, the renalase active site is fully solvent exposed and lacks an 'aromatic cage' for binding the substrate amino group. Renalase has an extremely low diaphorase activity, displaying lower k(cat) but higher k(cat)/K(m) for NADH compared to NADPH. Moreover, its FAD prosthetic group becomes slowly reduced when it is incubated with NADPH under anaerobiosis, and binds NAD(+) or NADP(+) with K(d) values of ca 2 mM. The absence of a recognizable NADP-binding site in the protein structure and its poor affinity for, and poor reactivity towards, NADH and NADPH suggest that these are not physiological ligands of renalase. Although our study does not answer the question on the catalytic activity of renalase, it provides a firm framework for testing hypotheses on the molecular mechanism of its action.
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