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Hawkins-van der Cingel G, Walsh SB, Eckardt KU, Knauf F. Oxalate Metabolism: From Kidney Stones to Cardiovascular Disease. Mayo Clin Proc 2024:S0025-6196(24)00090-9. [PMID: 38762815 DOI: 10.1016/j.mayocp.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/24/2024] [Accepted: 02/09/2024] [Indexed: 05/20/2024]
Abstract
Oxalate kidney stones are common and exert a huge burden of morbidity worldwide. However, circulating or excreted concentrations of oxalate are rarely measured. We argue that oxalate and its metabolism are important above and beyond kidney stone formation. There is emerging evidence that increased concentrations of oxalate could be a driver of chronic kidney disease progression. Furthermore, oxalate has been implicated in cardiovascular disease. Thus, the reduction of elevated plasma oxalate concentrations may represent a novel cardioprotective and nephroprotective strategy.
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Affiliation(s)
- Gerlineke Hawkins-van der Cingel
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany; UCL Department of Renal Medicine, University College London, London, United Kingdom.
| | - Stephen B Walsh
- UCL Department of Renal Medicine, University College London, London, United Kingdom
| | - Kai-Uwe Eckardt
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
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2
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Noonin C, Thongboonkerd V. Beneficial roles of gastrointestinal and urinary microbiomes in kidney stone prevention via their oxalate-degrading ability and beyond. Microbiol Res 2024; 282:127663. [PMID: 38422861 DOI: 10.1016/j.micres.2024.127663] [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: 11/17/2023] [Revised: 02/11/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024]
Abstract
Formation of calcium oxalate (CaOx) crystal, the most common composition in kidney stones, occurs following supersaturation of calcium and oxalate ions in the urine. In addition to endogenous source, another main source of calcium and oxalate ions is dietary intake. In the intestinal lumen, calcium can bind with oxalate to form precipitates to be eliminated with feces. High intake of oxalate-rich foods, inappropriate amount of daily calcium intake, defective intestinal transporters for oxalate secretion and absorption, and gastrointestinal (GI) malabsorption (i.e., from gastric bypass surgery) can enhance intestinal oxalate absorption, thereby increasing urinary oxalate level and risk of kidney stone disease (KSD). The GI microbiome rich with oxalate-degrading bacteria can reduce intestinal oxalate absorption and urinary oxalate level. In addition to the oxalate-degrading ability, the GI microbiome also affects expression of oxalate transporters and net intestinal oxalate transport, cholesterol level, and short-chain fatty acids (SCFAs) production, leading to lower KSD risk. Recent evidence also shows beneficial effects of urinary microbiome in KSD prevention. This review summarizes the current knowledge on the aforementioned aspects. Potential benefits of the GI and urinary microbiomes as probiotics for KSD prevention are emphasized. Finally, challenges and future perspectives of probiotic treatment in KSD are discussed.
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Affiliation(s)
- Chadanat Noonin
- Medical Proteomics Unit, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
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3
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Becker HM, Seidler UE. Bicarbonate secretion and acid/base sensing by the intestine. Pflugers Arch 2024; 476:593-610. [PMID: 38374228 PMCID: PMC11006743 DOI: 10.1007/s00424-024-02914-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 02/21/2024]
Abstract
The transport of bicarbonate across the enterocyte cell membrane regulates the intracellular as well as the luminal pH and is an essential part of directional fluid movement in the gut. Since the first description of "active" transport of HCO3- ions against a concentration gradient in the 1970s, the fundamental role of HCO3- transport for multiple intestinal functions has been recognized. The ion transport proteins have been identified and molecularly characterized, and knockout mouse models have given insight into their individual role in a variety of functions. This review describes the progress made in the last decade regarding novel techniques and new findings in the molecular regulation of intestinal HCO3- transport in the different segments of the gut. We discuss human diseases with defects in intestinal HCO3- secretion and potential treatment strategies to increase luminal alkalinity. In the last part of the review, the cellular and organismal mechanisms for acid/base sensing in the intestinal tract are highlighted.
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Affiliation(s)
- Holger M Becker
- Department of Gastroenterology, Hannover Medical School, 30625, Hannover, Germany
| | - Ursula E Seidler
- Department of Gastroenterology, Hannover Medical School, 30625, Hannover, Germany.
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4
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Choy WH, Adler A, Morgan-Lang C, Gough EK, Hallam SJ, Manges AR, Chew BH, Penniston K, Miller A, Lange D. Deficient butyrate metabolism in the intestinal microbiome is a potential risk factor for recurrent kidney stone disease. Urolithiasis 2024; 52:38. [PMID: 38413462 DOI: 10.1007/s00240-024-01534-x] [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: 10/17/2023] [Accepted: 01/16/2024] [Indexed: 02/29/2024]
Abstract
Intestinal microbiome dysbiosis is a known risk factor for recurrent kidney stone disease (KSD) with prior data suggesting a role for dysfunctional metabolic pathways other than those directly utilizing oxalate. To identify alternative mechanisms, the current study analyzed differences in the metabolic potential of intestinal microbiomes of patients (n = 17) and live-in controls (n = 17) and determined their relevance to increased risk for KSD using shotgun metagenomic sequencing. We found no differences in the abundance of genes associated with known oxalate degradation pathways, supporting the notion that dysfunction in other metabolic pathways plays a role in KSD. Further analysis showed decreased abundance of key enzymes involved in butyrate biosynthesis in patient intestinal microbiomes. Furthermore, de novo construction of microbial genomes showed that the majority of genes significantly enriched in non-stone formers are affiliated with Faecalibacterium prausnitzii, a major butyrate producer. Specifically pertaining to butyrate metabolism, the majority of abundant genes mapped back to F. prausnitzii, Alistipes spp., and Akkermansia muciniphila. No differences were observed in ascorbate or glyoxylate metabolic pathways. Collectively, these data suggest that impaired bacterial-associated butyrate metabolism may be an oxalate-independent mechanism that contributes to an increased risk for recurrent KSD. This indicates that the role of the intestinal microbiome in recurrent KSD is multi-factorial, which is representative of the highly intertwined metabolic nature of this complex environment. Future bacteria-based treatments must not be restricted to targeting only oxalate metabolism.
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Affiliation(s)
- Wai Ho Choy
- Department of Urologic Sciences, The Stone Centre at VGH, University of British Columbia, Jack Bell Research Centre, Rm. 550-3, 2660 Oak Street, Vancouver, BC, V6J 1G7, Canada
| | - Ava Adler
- Departments of Urology and Immunology, Cleveland Clinic, Cleveland, OH, USA
| | - Connor Morgan-Lang
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, BC, Canada
| | - Ethan K Gough
- Johns Hopkins Bloomberg School of Public Health US, Baltimore, USA
| | - Steven J Hallam
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Genome Science and Technology Program, University of British Columbia, Vancouver, BC, Canada
- ECOSCOPE Training Program, University of British Columbia, Vancouver, BC, Canada
| | - Amee R Manges
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
- BC Centre for Disease Control, Vancouver, BC, Canada
| | - Ben H Chew
- Department of Urologic Sciences, The Stone Centre at VGH, University of British Columbia, Jack Bell Research Centre, Rm. 550-3, 2660 Oak Street, Vancouver, BC, V6J 1G7, Canada
| | - Kristina Penniston
- Department of Urology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Aaron Miller
- Departments of Urology and Immunology, Cleveland Clinic, Cleveland, OH, USA
| | - Dirk Lange
- Department of Urologic Sciences, The Stone Centre at VGH, University of British Columbia, Jack Bell Research Centre, Rm. 550-3, 2660 Oak Street, Vancouver, BC, V6J 1G7, Canada.
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5
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Geertsma ER, Oliver D. SLC26 Anion Transporters. Handb Exp Pharmacol 2024; 283:319-360. [PMID: 37947907 DOI: 10.1007/164_2023_698] [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] [Indexed: 11/12/2023]
Abstract
Solute carrier family 26 (SLC26) is a family of functionally diverse anion transporters found in all kingdoms of life. Anions transported by SLC26 proteins include chloride, bicarbonate, and sulfate, but also small organic dicarboxylates such as fumarate and oxalate. The human genome encodes ten functional homologs, several of which are causally associated with severe human diseases, highlighting their physiological importance. Here, we review novel insights into the structure and function of SLC26 proteins and summarize the physiological relevance of human members.
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Affiliation(s)
- Eric R Geertsma
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Dominik Oliver
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Marburg, Germany.
- Center for Mind, Brain and Behavior (CMBB), Universities of Marburg and Giessen, Marburg, Giessen, Germany.
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6
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Baltazar P, de Melo Junior AF, Fonseca NM, Lança MB, Faria A, Sequeira CO, Teixeira-Santos L, Monteiro EC, Campos Pinheiro L, Calado J, Sousa C, Morello J, Pereira SA. Oxalate (dys)Metabolism: Person-to-Person Variability, Kidney and Cardiometabolic Toxicity. Genes (Basel) 2023; 14:1719. [PMID: 37761859 PMCID: PMC10530622 DOI: 10.3390/genes14091719] [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: 06/25/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 09/29/2023] Open
Abstract
Oxalate is a metabolic end-product whose systemic concentrations are highly variable among individuals. Genetic (primary hyperoxaluria) and non-genetic (e.g., diet, microbiota, renal and metabolic disease) reasons underlie elevated plasma concentrations and tissue accumulation of oxalate, which is toxic to the body. A classic example is the triad of primary hyperoxaluria, nephrolithiasis, and kidney injury. Lessons learned from this example suggest further investigation of other putative factors associated with oxalate dysmetabolism, namely the identification of precursors (glyoxylate, aromatic amino acids, glyoxal and vitamin C), the regulation of the endogenous pathways that produce oxalate, or the microbiota's contribution to oxalate systemic availability. The association between secondary nephrolithiasis and cardiovascular and metabolic diseases (hypertension, type 2 diabetes, and obesity) inspired the authors to perform this comprehensive review about oxalate dysmetabolism and its relation to cardiometabolic toxicity. This perspective may offer something substantial that helps advance understanding of effective management and draws attention to the novel class of treatments available in clinical practice.
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Affiliation(s)
- Pedro Baltazar
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Antonio Ferreira de Melo Junior
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Nuno Moreira Fonseca
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Miguel Brito Lança
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
| | - Ana Faria
- CHRC, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal;
| | - Catarina O. Sequeira
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
| | - Luísa Teixeira-Santos
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Emilia C. Monteiro
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Luís Campos Pinheiro
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Joaquim Calado
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
- ToxOmics, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal
| | - Cátia Sousa
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Judit Morello
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
| | - Sofia A. Pereira
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
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7
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Arvans D, Chang C, Alshaikh A, Tesar C, Babnigg G, Wolfgeher D, Kron S, Antonopoulos D, Bashir M, Cham C, Musch M, Chang E, Joachimiak A, Hassan H. Sel1-like proteins and peptides are the major Oxalobacter formigenes-derived factors stimulating oxalate transport by human intestinal epithelial cells. Am J Physiol Cell Physiol 2023; 325:C344-C361. [PMID: 37125773 PMCID: PMC10393326 DOI: 10.1152/ajpcell.00466.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 04/10/2023] [Accepted: 04/13/2023] [Indexed: 05/02/2023]
Abstract
Kidney stones (KSs) are very common, excruciating, and associated with tremendous healthcare cost, chronic kidney disease (CKD), and kidney failure (KF). Most KSs are composed of calcium oxalate and small increases in urinary oxalate concentration significantly enhance the stone risk. Oxalate also potentially contributes to CKD progression, kidney disease-associated cardiovascular diseases, and poor renal allograft survival. This emphasizes the urgent need for plasma and urinary oxalate lowering therapies, which can be achieved by enhancing enteric oxalate secretion. We previously identified Oxalobacter formigenes (O. formigenes)-derived factors secreted in its culture-conditioned medium (CM), which stimulate oxalate transport by human intestinal Caco2-BBE (C2) cells and reduce urinary oxalate excretion in hyperoxaluric mice by enhancing colonic oxalate secretion. Given their remarkable therapeutic potential, we now identified Sel1-like proteins as the major O. formigenes-derived secreted factors using mass spectrometry and functional assays. Crystal structures for six proteins were determined to confirm structures and better understand functions. OxBSel1-14-derived small peptides P8 and P9 were identified as the major factors, with P8 + 9 closely recapitulating the CM's effects, acting through the oxalate transporters SLC26A2 and SLC26A6 and PKA activation. Besides C2 cells, P8 + 9 also stimulate oxalate transport by human ileal and colonic organoids, confirming that they work in human tissues. In conclusion, P8 and P9 peptides are identified as the major O. formigenes-derived secreted factors and they have significant therapeutic potential for hyperoxalemia, hyperoxaluria, and related disorders, impacting the outcomes of patients suffering from KSs, enteric hyperoxaluria, primary hyperoxaluria, CKD, KF, and renal transplant recipients.NEW & NOTEWORTHY We previously identified Oxalobacter formigenes-derived secreted factors stimulating oxalate transport by human intestinal epithelial cells in vitro and reducing urinary oxalate excretion in hyperoxaluric mice by enhancing colonic oxalate secretion. We now identified Sel1-like proteins and small peptides as the major secreted factors and they have significant therapeutic potential for hyperoxalemia and hyperoxaluria, impacting the outcomes of patients suffering from kidney stones, primary and secondary hyperoxaluria, chronic kidney disease, kidney failure, and renal transplant recipients.
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Affiliation(s)
- Donna Arvans
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States
| | - Changsoo Chang
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, Illinois, United States
| | - Altayeb Alshaikh
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States
| | - Christine Tesar
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, Illinois, United States
| | - Gyorgy Babnigg
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States
| | - Don Wolfgeher
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, United States
| | - Stephen Kron
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, United States
| | | | - Mohamed Bashir
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States
| | - Candace Cham
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States
| | - Mark Musch
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States
| | - Eugene Chang
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States
| | - Andrzej Joachimiak
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, Illinois, United States
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States
| | - Hatim Hassan
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States
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8
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Chen T, Qian B, Zou J, Luo P, Zou J, Li W, Chen Q, Zheng L. Oxalate as a potent promoter of kidney stone formation. Front Med (Lausanne) 2023; 10:1159616. [PMID: 37342493 PMCID: PMC10278359 DOI: 10.3389/fmed.2023.1159616] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/09/2023] [Indexed: 06/23/2023] Open
Abstract
Kidney stones are among the most prevalent urological diseases, with a high incidence and recurrence rate. Treating kidney stones has been greatly improved by the development of various minimally invasive techniques. Currently, stone treatment is relatively mature. However, most current treatment methods are limited to stones and cannot effectively reduce their incidence and recurrence. Therefore, preventing disease occurrence, development, and recurrence after treatment, has become an urgent issue. The etiology and pathogenesis of stone formation are key factors in resolving this issue. More than 80% of kidney stones are calcium oxalate stones. Several studies have studied the formation mechanism of stones from the metabolism of urinary calcium, but there are few studies on oxalate, which plays an equally important role in stone formation. Oxalate and calcium play equally important roles in calcium oxalate stones, whereas the metabolism and excretion disorders of oxalate play a crucial role in their occurrence. Therefore, starting from the relationship between renal calculi and oxalate metabolism, this work reviews the occurrence of renal calculi, oxalate absorption, metabolism, and excretion mechanisms, focusing on the key role of SLC26A6 in oxalate excretion and the regulatory mechanism of SLC26A6 in oxalate transport. This review provides some new clues for the mechanism of kidney stones from the perspective of oxalate to improve the understanding of the role of oxalate in the formation of kidney stones and to provide suggestions for reducing the incidence and recurrence rate of kidney stones.
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Affiliation(s)
- Tao Chen
- The First Clinical College, Gannan Medical University, Ganzhou, Jiangxi, China
- Department of Urology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
- Key Laboratory of Urology and Andrology of Ganzhou, Ganzhou, Jiangxi, China
| | - Biao Qian
- Department of Urology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
- Key Laboratory of Urology and Andrology of Ganzhou, Ganzhou, Jiangxi, China
| | - Junrong Zou
- Department of Urology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
- Key Laboratory of Urology and Andrology of Ganzhou, Ganzhou, Jiangxi, China
| | - Peiyue Luo
- The First Clinical College, Gannan Medical University, Ganzhou, Jiangxi, China
- Department of Urology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
- Key Laboratory of Urology and Andrology of Ganzhou, Ganzhou, Jiangxi, China
| | - Jun Zou
- The First Clinical College, Gannan Medical University, Ganzhou, Jiangxi, China
- Department of Urology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
- Key Laboratory of Urology and Andrology of Ganzhou, Ganzhou, Jiangxi, China
| | - Wei Li
- The First Clinical College, Gannan Medical University, Ganzhou, Jiangxi, China
- Department of Urology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
- Key Laboratory of Urology and Andrology of Ganzhou, Ganzhou, Jiangxi, China
| | - Qi Chen
- The First Clinical College, Gannan Medical University, Ganzhou, Jiangxi, China
- Department of Urology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
- Key Laboratory of Urology and Andrology of Ganzhou, Ganzhou, Jiangxi, China
| | - Liying Zheng
- Department of Graduate, The First Affiliated Hospital of Ganna Medical University, Ganzhou, Jiangxi, China
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9
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Ermer T, Nazzal L, Tio MC, Waikar S, Aronson PS, Knauf F. Oxalate homeostasis. Nat Rev Nephrol 2023; 19:123-138. [PMID: 36329260 DOI: 10.1038/s41581-022-00643-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
Oxalate homeostasis is maintained through a delicate balance between endogenous sources, exogenous supply and excretion from the body. Novel studies have shed light on the essential roles of metabolic pathways, the microbiome, epithelial oxalate transporters, and adequate oxalate excretion to maintain oxalate homeostasis. In patients with primary or secondary hyperoxaluria, nephrolithiasis, acute or chronic oxalate nephropathy, or chronic kidney disease irrespective of aetiology, one or more of these elements are disrupted. The consequent impairment in oxalate homeostasis can trigger localized and systemic inflammation, progressive kidney disease and cardiovascular complications, including sudden cardiac death. Although kidney replacement therapy is the standard method for controlling elevated plasma oxalate concentrations in patients with kidney failure requiring dialysis, more research is needed to define effective elimination strategies at earlier stages of kidney disease. Beyond well-known interventions (such as dietary modifications), novel therapeutics (such as small interfering RNA gene silencers, recombinant oxalate-degrading enzymes and oxalate-degrading bacterial strains) hold promise to improve the outlook of patients with oxalate-related diseases. In addition, experimental evidence suggests that anti-inflammatory medications might represent another approach to mitigating or resolving oxalate-induced conditions.
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Affiliation(s)
- Theresa Ermer
- Department of Surgery, Division of Thoracic Surgery, Yale School of Medicine, New Haven, CT, USA
| | - Lama Nazzal
- Department of Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Maria Clarissa Tio
- Division of Nephrology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Sushrut Waikar
- Department of Medicine, Section of Nephrology, Boston University, Boston, MA, USA
| | - Peter S Aronson
- Department of Internal Medicine, Section of Nephrology, Yale School of Medicine, New Haven, CT, USA
| | - Felix Knauf
- Department of Internal Medicine, Section of Nephrology, Yale School of Medicine, New Haven, CT, USA. .,Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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10
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Whittamore JM, Hatch M. Oxalate secretion is stimulated by a cAMP-dependent pathway in the mouse cecum. Pflugers Arch 2023; 475:249-266. [PMID: 36044064 PMCID: PMC9851989 DOI: 10.1007/s00424-022-02742-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/06/2022] [Accepted: 08/18/2022] [Indexed: 02/01/2023]
Abstract
Elevated levels of the intracellular second messenger cAMP can stimulate intestinal oxalate secretion however the membrane transporters responsible are unclear. Oxalate transport by the chloride/bicarbonate (Cl-/HCO3-) exchanger Slc26a6 or PAT-1 (Putative Anion Transporter 1), is regulated via cAMP when expressed in Xenopus oocytes and cultured cells but whether this translates to the native epithelia is unknown. This study investigated the regulation of oxalate transport by the mouse intestine focusing on transport at the apical membrane hypothesizing PAT-1 is the target of a cAMP-dependent signaling pathway. Adopting the Ussing chamber technique we measured unidirectional 14C-oxalate and 36Cl- flux ([Formula: see text] and [Formula: see text]) across distal ileum, cecum and distal colon, employing forskolin (FSK) and 3-isobutyl-1-methylxanthine (IBMX) to trigger cAMP production. FSK/IBMX initiated a robust secretory response by all segments but the stimulation of net oxalate secretion was confined to the cecum only involving activation of [Formula: see text] and distinct from net Cl- secretion produced by inhibiting [Formula: see text]. Using the PAT-1 knockout (KO) mouse we determined cAMP-stimulated [Formula: see text] was not directly dependent on PAT-1, but it was sensitive to mucosal DIDS (4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid), although unlikely to be another Cl-/HCO3- exchanger given the lack of trans-stimulation or cis-inhibition by luminal Cl- or HCO3-. The cAMP-activated oxalate efflux was reliant on CFTR (Cystic Fibrosis Transmembrane conductance Regulator) activity, but only in the presence of PAT-1, leading to speculation on the involvement of a multi-transporter regulatory complex. Further investigations at the cellular and molecular level are necessary to define the mechanism and transporter(s) responsible.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA.
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research | Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-8885, USA.
| | - Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
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11
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Genetic assessment in primary hyperoxaluria: why it matters. Pediatr Nephrol 2023; 38:625-634. [PMID: 35695965 PMCID: PMC9842587 DOI: 10.1007/s00467-022-05613-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/23/2022] [Accepted: 04/29/2022] [Indexed: 01/21/2023]
Abstract
Accurate diagnosis of primary hyperoxaluria (PH) has important therapeutic consequences. Since biochemical assessment can be unreliable, genetic testing is a crucial diagnostic tool for patients with PH to define the disease type. Patients with PH type 1 (PH1) have a worse prognosis than those with other PH types, despite the same extent of oxalate excretion. The relation between genotype and clinical phenotype in PH1 is extremely heterogeneous with respect to age of first symptoms and development of kidney failure. Some mutations are significantly linked to pyridoxine-sensitivity in PH1, such as homozygosity for p.G170R and p.F152I combined with a common polymorphism. Although patients with these mutations display on average better outcomes, they may also present with CKD stage 5 in infancy. In vitro studies suggest pyridoxine-sensitivity for some other mutations, but confirmatory clinical data are lacking (p.G47R, p.G161R, p.I56N/major allele) or scarce (p.I244T). These studies also suggest that other vitamin B6 derivatives than pyridoxine may be more effective and should be a focus for clinical testing. PH patients displaying the same mutation, even within one family, may have completely different clinical outcomes. This discordance may be caused by environmental or genetic factors that are unrelated to the effect of the causative mutation(s). No relation between genotype and clinical or biochemical phenotypes have been found so far in PH types 2 and 3. This manuscript reviews the current knowledge on the genetic background of the three types of primary hyperoxaluria and its impact on clinical management, including prenatal diagnosis.
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12
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Giannos P, Prokopidis K, Isanejad M, Wright HL. Markers of immune dysregulation in response to the ageing gut: insights from aged murine gut microbiota transplants. BMC Gastroenterol 2022; 22:533. [PMID: 36544093 PMCID: PMC9773626 DOI: 10.1186/s12876-022-02613-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Perturbations in the composition and diversity of the gut microbiota are accompanied by a decline in immune homeostasis during ageing, characterized by chronic low-grade inflammation and enhanced innate immunity. Genetic insights into the interaction between age-related alterations in the gut microbiota and immune function remain largely unexplored. METHODS We investigated publicly available transcriptomic gut profiles of young germ-free mouse hosts transplanted with old donor gut microbiota to identify immune-associated differentially expressed genes (DEGs). Literature screening of the Gene Expression Omnibus and PubMed identified one murine (Mus musculus) gene expression dataset (GSE130026) that included small intestine tissues from young (5-6 weeks old) germ-free mice hosts that were compared following 8 weeks after transplantation with either old (~ 24-month old; n = 5) or young (5-6 weeks old; n = 4) mouse donor gut microbiota. RESULTS A total of 112 differentially expressed genes (DEGs) were identified and used to construct a gut network of encoded proteins, in which DEGs were functionally annotated as being involved in an immune process based on gene ontology. The association between the expression of immune-process DEGs and abundance of immune infiltrates from gene signatures in normal colorectal tissues was estimated from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) project. The analysis revealed a 25-gene signature of immune-associated DEGs and their expression profile was positively correlated with naïve T-cell, effector memory T-cell, central memory T-cell, resident memory T-cell, exhausted T-cell, resting Treg T-cell, effector Treg T-cell and Th1-like colorectal gene signatures. Conclusions These genes may have a potential role as candidate markers of immune dysregulation during gut microbiota ageing. Moreover, these DEGs may provide insights into the altered immune response to microbiota in the ageing gut, including reduced antigen presentation and alterations in cytokine and chemokine production.
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Affiliation(s)
- Panagiotis Giannos
- Society of Meta-Research and Biomedical Innovation, London, UK.,Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Konstantinos Prokopidis
- Society of Meta-Research and Biomedical Innovation, London, UK.,Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK
| | - Masoud Isanejad
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK
| | - Helen L Wright
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK.
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13
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Lee D, Lee PCW, Hong JH, Shin DM. Estrogen treatment reduced oxalate transporting activity and enhanced migration through the involvement of SLC26A6 in lung cancer cells. Toxicol In Vitro 2022; 82:105373. [DOI: 10.1016/j.tiv.2022.105373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/19/2022] [Accepted: 04/26/2022] [Indexed: 11/30/2022]
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14
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Cornière N, Thomson RB, Thauvin S, Villoutreix BO, Karp S, Dynia DW, Burlein S, Brinkmann L, Badreddine A, Dechaume A, Derhourhi M, Durand E, Vaillant E, Froguel P, Chambrey R, Aronson PS, Bonnefond A, Eladari D. Dominant negative mutation in oxalate transporter SLC26A6 associated with enteric hyperoxaluria and nephrolithiasis. J Med Genet 2022; 59:1035-1043. [PMID: 35115415 PMCID: PMC9346097 DOI: 10.1136/jmedgenet-2021-108256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/11/2022] [Indexed: 11/30/2022]
Abstract
Background Nephrolithiasis (NL) is a complex multifactorial disease affecting up to 10%–20% of the human population and causing a significant burden on public health systems worldwide. It results from a combination of environmental and genetic factors. Hyperoxaluria is a major risk factor for NL. Methods We used a whole exome-based approach in a patient with calcium oxalate NL. The effects of the mutation were characterised using cell culture and in silico analyses. Results We identified a rare heterozygous missense mutation (c.1519C>T/p.R507W) in the SLC26A6 gene that encodes a secretory oxalate transporter. This mutation cosegregated with hyperoxaluria in the family. In vitro characterisation of mutant SLC26A6 demonstrated that Cl−-dependent oxalate transport was dramatically reduced because the mutation affects both SLC26A6 transport activity and membrane surface expression. Cotransfection studies demonstrated strong dominant-negative effects of the mutant on the wild-type protein indicating that the phenotype of patients heterozygous for this mutation may be more severe than predicted by haploinsufficiency alone. Conclusion Our study is in line with previous observations made in the mouse showing that SLC26A6 inactivation can cause inherited enteric hyperoxaluria with calcium oxalate NL. Consistent with an enteric form of hyperoxaluria, we observed a beneficial effect of increasing calcium in the patient’s diet to reduce urinary oxalate excretion.
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Affiliation(s)
- Nicolas Cornière
- Department of Precision Médicine for Metabolic and Renal Diseases, CHU Amiens Picardie, Université de Picardie Jules Verne, Amiens, France.,UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - R Brent Thomson
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | - Sophie Karp
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Diane W Dynia
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sarah Burlein
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lennart Brinkmann
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Alaa Badreddine
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - Aurélie Dechaume
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - Mehdi Derhourhi
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - Emmanuelle Durand
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - Emmanuel Vaillant
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - Philippe Froguel
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - Régine Chambrey
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France.,Plateau de Recherche ODHIR, AURAR, Saint-Gilles-les-Bains, Réunion
| | - Peter S Aronson
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Amélie Bonnefond
- UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
| | - Dominique Eladari
- Department of Precision Médicine for Metabolic and Renal Diseases, CHU Amiens Picardie, Université de Picardie Jules Verne, Amiens, France .,UMR1283, INSERM; CNRS; University of Lille, Lille, Hauts de France, France
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15
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Whittamore JM, Hatch M. Oxalate Flux Across the Intestine: Contributions from Membrane Transporters. Compr Physiol 2021; 12:2835-2875. [PMID: 34964122 DOI: 10.1002/cphy.c210013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epithelial oxalate transport is fundamental to the role occupied by the gastrointestinal (GI) tract in oxalate homeostasis. The absorption of dietary oxalate, together with its secretion into the intestine, and degradation by the gut microbiota, can all influence the excretion of this nonfunctional terminal metabolite in the urine. Knowledge of the transport mechanisms is relevant to understanding the pathophysiology of hyperoxaluria, a risk factor in kidney stone formation, for which the intestine also offers a potential means of treatment. The following discussion presents an expansive review of intestinal oxalate transport. We begin with an overview of the fate of oxalate, focusing on the sources, rates, and locations of absorption and secretion along the GI tract. We then consider the mechanisms and pathways of transport across the epithelial barrier, discussing the transcellular, and paracellular components. There is an emphasis on the membrane-bound anion transporters, in particular, those belonging to the large multifunctional Slc26 gene family, many of which are expressed throughout the GI tract, and we summarize what is currently known about their participation in oxalate transport. In the final section, we examine the physiological stimuli proposed to be involved in regulating some of these pathways, encompassing intestinal adaptations in response to chronic kidney disease, metabolic acid-base disorders, obesity, and following gastric bypass surgery. There is also an update on research into the probiotic, Oxalobacter formigenes, and the basis of its unique interaction with the gut epithelium. © 2021 American Physiological Society. Compr Physiol 11:1-41, 2021.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
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16
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Short-Chain Fatty Acids Reduced Renal Calcium Oxalate Stones by Regulating the Expression of Intestinal Oxalate Transporter SLC26A6. mSystems 2021; 6:e0104521. [PMID: 34783577 PMCID: PMC8594443 DOI: 10.1128/msystems.01045-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Renal calcium oxalate (CaOx) stone is a common urologic disease with a high prevalence and recurrence rate. However, short-chain fatty acids (SCFAs) are less often reported in the prevention of urolithiasis. This study aimed to explore the effect of SCFAs on the renal CaOx stone formation and the underlying mechanisms. Ethylene glycol was used to induce renal CaOx crystals in rats. SCFAs (acetate, propionate, or butyrate) were added as supplements to the drinking water with or without antibiotics. Because intestinal oxalate transporters SLC26A6 and SLC26A3 regulate the excretion and absorption of oxalate in the intestine, we injected adeno-associated virus 9 (AAV9)-SLC26A6-shRNA (short hairpin RNA) and AAV9-SLC26A3 into the tail vein of rats to suppress SLC26A6 and overexpress SLC26A3 expression in the intestine, respectively, to explore the role of SLC26A3 and SLC26A6 (SLC26A3/6) in the reduction of renal CaOx crystals induced by SCFAs. Results showed that SCFAs reduced renal CaOx crystals and urinary oxalate levels but, however, increased the abundance of SCFA-producing bacteria and cecum SCFA levels. SCFA supplements still reduced renal crystals and urinary oxalate after gut microbiota depletion. Propionate and butyrate downregulated intestinal oxalate transporter SLC26A3 expression, while acetate and propionate upregulated SLC26A6 expression, both in vivo and in vitro. AAV9-SLC26A3 exerted a protective effect against renal crystals, while AAV9-SLC26A6-shRNA contributed to the renal crystal formation even though the SCFAs were supplemented. In conclusion, SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones. IMPORTANCE Some studies found that the relative abundances of short-chain-fatty-acid (SCFA)-producing bacteria were lower in the gut microbiota of renal stone patients than healthy controls. Our previous study demonstrated that SCFAs could reduce the formation of renal calcium oxalate (CaOx) stones, but the mechanism is still unknown. In this study, we found that SCFAs (acetate, propionate, and butyrate) reduced the formation of renal calcium oxalate (CaOx) crystals and the level of urinary oxalate. Depleting gut microbiota increased the amount of renal crystals in model rats, and SCFA supplements reduced renal crystals and urinary oxalate after gut microbiota depletion. Intestinal oxalate transporter SLC26A6 was a direct target of SCFAs. Our findings suggested that SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones.
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17
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Yang X, Yao S, An J, Jin H, Wang H, Tuo B. SLC26A6 and NADC‑1: Future direction of nephrolithiasis and calculus‑related hypertension research (Review). Mol Med Rep 2021; 24:745. [PMID: 34458928 DOI: 10.3892/mmr.2021.12385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 07/30/2021] [Indexed: 11/06/2022] Open
Abstract
Nephrolithiasis is the most common type of urinary system disease in developed countries, with high morbidity and recurrence rates. Nephrolithiasis is a serious health problem, which eventually leads to the loss of renal function and is closely related to hypertension. Modern medicine has adopted minimally invasive surgery for the management of kidney stones, but this does not resolve the root of the problem. Thus, nephrolithiasis remains a major public health issue, the causes of which remain largely unknown. Researchers have attempted to determine the causes and therapeutic targets of kidney stones and calculus‑related hypertension. Solute carrier family 26 member 6 (SLC26A6), a member of the well‑conserved solute carrier family 26, is highly expressed in the kidney and intestines, and it primarily mediates the transport of various anions, including OXa2‑, HCO3‑, Cl‑ and SO42‑, amongst others. Na+‑dependent dicarboxylate‑1 (NADC‑1) is the Na+‑carboxylate co‑transporter of the SLC13 gene family, which primarily mediates the co‑transport of Na+ and tricarboxylic acid cycle intermediates, such as citrate and succinate, amongst others. Studies have shown that Ca2+ oxalate kidney stones are the most prevalent type of kidney stones. Hyperoxaluria and hypocitraturia notably increase the risk of forming Ca2+ oxalate kidney stones, and the increase in succinate in the juxtaglomerular device can stimulate renin secretion and lead to hypertension. Whilst it is known that it is important to maintain the dynamic equilibrium of oxalate and citrate in the kidney, the synergistic molecular mechanisms underlying the transport of oxalate and citrate across kidney epithelial cells have undergone limited investigations. The present review examines the results from early reports studying oxalate transport and citrate transport in the kidney, describing the synergistic molecular mechanisms of SLC26A6 and NADC‑1 in the process of nephrolithiasis formation. A growing body of research has shown that nephrolithiasis is intricately associated with hypertension. Additionally, the recent investigations into the mediation of succinate via regulation of the synergistic molecular mechanism between the SLC26A6 and NADC‑1 transporters is summarized, revealing their functional role and their close association with the inositol triphosphate receptor‑binding protein to regulate blood pressure.
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Affiliation(s)
- Xingyue Yang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Shun Yao
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jiaxing An
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Hai Jin
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Hui Wang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
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18
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Stephens CE, Whittamore JM, Hatch M. The role of NHE3 (Slc9a3) in oxalate and sodium transport by mouse intestine and regulation by cAMP. Physiol Rep 2021; 9:e14828. [PMID: 33904662 PMCID: PMC8077127 DOI: 10.14814/phy2.14828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/01/2021] [Accepted: 03/09/2021] [Indexed: 12/14/2022] Open
Abstract
Intestinal oxalate transport involves Cl−/HCO3− exchangers but how this transport is regulated is not currently known. NHE3 (Slc9a3), an apical Na+/H+ exchanger, is an established target for regulation of electroneutral NaCl absorption working in concert with Cl−/HCO3− exchangers. To test whether NHE3 could be involved in regulation of intestinal oxalate transport and renal oxalate handling we compared urinary oxalate excretion rates and intestinal transepithelial fluxes of 14C‐oxalate and 22Na+ between NHE3 KO and wild‐type (WT) mice. NHE3 KO kidneys had lower creatinine clearance suggesting reduced GFR, but urinary oxalate excretion rates (µmol/24 h) were similar compared to the WT but doubled when expressed as a ratio of creatinine. Intestinal transepithelial fluxes of 14C‐oxalate and 22Na+ were measured in the distal ileum, cecum, and distal colon. The absence of NHE3 did not affect basal net transport rates of oxalate or sodium across any intestinal section examined. Stimulation of intracellular cAMP with forskolin (FSK) and 3‐isobutyl‐1‐methylxanthine (IBMX) led to an increase in net oxalate secretion in the WT distal ileum and cecum and inhibition of sodium absorption in the cecum and distal colon. In NHE3 KO cecum, cAMP stimulation of oxalate secretion was impaired suggesting the possibility of a role for NHE3 in this process. Although, there is little evidence for a role of NHE3 in basal intestinal oxalate fluxes, NHE3 may be important for cAMP stimulation of oxalate in the cecum and for renal handling of oxalate.
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Affiliation(s)
- Christine E Stephens
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Jonathan M Whittamore
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Marguerite Hatch
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
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19
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Witting C, Langman CB, Assimos D, Baum MA, Kausz A, Milliner D, Tasian G, Worcester E, Allain M, West M, Knauf F, Lieske JC. Pathophysiology and Treatment of Enteric Hyperoxaluria. Clin J Am Soc Nephrol 2021; 16:487-495. [PMID: 32900691 PMCID: PMC8011014 DOI: 10.2215/cjn.08000520] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Enteric hyperoxaluria is a distinct entity that can occur as a result of a diverse set of gastrointestinal disorders that promote fat malabsorption. This, in turn, leads to excess absorption of dietary oxalate and increased urinary oxalate excretion. Hyperoxaluria increases the risk of kidney stones and, in more severe cases, CKD and even kidney failure. The prevalence of enteric hyperoxaluria has increased over recent decades, largely because of the increased use of malabsorptive bariatric surgical procedures for medically complicated obesity. This systematic review of enteric hyperoxaluria was completed as part of a Kidney Health Initiative-sponsored project to describe enteric hyperoxaluria pathophysiology, causes, outcomes, and therapies. Current therapeutic options are limited to correcting the underlying gastrointestinal disorder, intensive dietary modifications, and use of calcium salts to bind oxalate in the gut. Evidence for the effect of these treatments on clinically significant outcomes, including kidney stone events or CKD, is currently lacking. Thus, further research is needed to better define the precise factors that influence risk of adverse outcomes, the long-term efficacy of available treatment strategies, and to develop new therapeutic approaches.
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Affiliation(s)
- Celeste Witting
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Craig B. Langman
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois,Division of Kidney Diseases, Lurie Children’s Hospital of Chicago, Chicago, Illinois
| | - Dean Assimos
- Department of Urology, University of Alabama-Birmingham, Birmingham, Alabama
| | - Michelle A. Baum
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Dawn Milliner
- Department of Internal Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Greg Tasian
- Department of Surgery, Division of Urology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Elaine Worcester
- Department of Medicine, University of Chicago, Chicago, Illinois
| | | | | | - Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - John C. Lieske
- Allena Pharmaceuticals, Inc., Newton, Massachusetts,Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
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Abstract
PURPOSE OF REVIEW The gut-kidney axis plays a critical role in oxalate homeostasis, and better understanding of oxalate transport regulatory mechanisms is essential for developing novel therapies. RECENT FINDINGS Oxalate potentially contributes to chronic kidney disease (CKD) progression, CKD - and end stage renal disease (ESRD)-associated cardiovascular diseases, polycystic kidney disease (PKD) progression, and/or poor renal allograft survival, emphasizing the need for plasma and urinary oxalate lowering therapies. One promising strategy would be to enhance the bowel's ability to secrete oxalate, which might be facilitated by the following findings. Oxalobacter formigenes (O. formigenes)-derived factors recapitulate O. formigenes colonization effects by reducing urinary oxalate excretion in hyperoxaluric mice by inducing colonic oxalate secretion. Protein kinase A activation stimulates intestinal oxalate transport by enhancing the surface expression of the oxalate transporter SLC26A6 (A6). Glycosylation also stimulates A6-mediated oxalate transport. The colon adapts to chronic acidosis in rats through increased colonic oxalate secretion as previously reported in CKD rats, and A6-mediated enteric oxalate secretion is critical in reducing the body oxalate burden in CKD mice. Intestinal oxalate transport is negatively regulated by proinflammatory cytokines and cholinergic, purinergic, and adenosinergic signaling. SUMMARY These findings could facilitate the development of novel therapeutics for hyperoxalemia, hyperoxaluria, and related disorders if similar regulatory mechanisms are confirmed in humans.
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Affiliation(s)
- Altayeb E Alshaikh
- University of Chicago Pritzker School of Medicine
- University of Chicago, Chicago, Illinois, USA
| | - Hatim A Hassan
- University of Chicago Pritzker School of Medicine
- University of Chicago, Chicago, Illinois, USA
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21
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Tarlinton RE, Fabijan J, Hemmatzadeh F, Meers J, Owen H, Sarker N, Seddon JM, Simmons G, Speight N, Trott DJ, Woolford L, Emes RD. Transcriptomic and genomic variants between koala populations reveals underlying genetic components to disorders in a bottlenecked population. CONSERV GENET 2021. [DOI: 10.1007/s10592-021-01340-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
AbstractHistorical hunting pressures on koalas in the southern part of their range in Australia have led to a marked genetic bottleneck when compared with their northern counterparts. There are a range of suspected genetic disorders such as testicular abnormalities, oxalate nephrosis and microcephaly reported at higher prevalence in these genetically restricted southern animals. This paper reports analysis of differential expression of genes from RNAseq of lymph nodes, SNPs present in genes and the fixation index (population differentiation due to genetic structure) of these SNPs from two populations, one in south east Queensland, representative of the northern genotype and one in the Mount Lofty Ranges South Australia, representative of the southern genotype. SNPs that differ between these two populations were significantly enriched in genes associated with brain diseases. Genes which were differentially expressed between the two populations included many associated with brain development or disease, and in addition a number associated with testicular development, including the androgen receptor. Finally, one of the 8 genes both differentially expressed and with a statistical difference in SNP frequency between populations was SLC26A6 (solute carrier family 26 member 6), an anion transporter that was upregulated in SA koalas and is associated with oxalate transport and calcium oxalate uroliths in humans. Together the differences in SNPs and gene expression described in this paper suggest an underlying genetic basis for several disorders commonly seen in southern Australian koalas, supporting the need for further research into the genetic basis of these conditions, and highlighting that genetic selection in managed populations may need to be considered in the future.
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Wang J, Wang W, Wang H, Tuo B. Physiological and Pathological Functions of SLC26A6. Front Med (Lausanne) 2021; 7:618256. [PMID: 33553213 PMCID: PMC7859274 DOI: 10.3389/fmed.2020.618256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/30/2020] [Indexed: 12/26/2022] Open
Abstract
Solute Carrier Family 26 (SLC26) is a conserved anion transporter family with 10 members in human (SLC26A1-A11, A10 being a pseudogene). All SLC26 genes except for SLC26A5 (prestin) are versatile anion exchangers with notable ability to transport a variety of anions. SLC26A6 has the most extensive exchange functions in the SLC26 family and is widely expressed in various organs and tissues of mammals. SLC26A6 has some special properties that make it play a particularly important role in ion homeostasis and acid-base balance. In the past few years, the function of SLC26A6 in the diseases has received increasing attention. SLC26A6 not only participates in the development of intestinal and pancreatic diseases but also serves a significant role in mediating nephrolithiasis, fetal skeletal dysplasia and arrhythmia. This review aims to explore the role of SLC26A6 in physiology and pathophysiology of relative mammalian organs to guide in-depth studies about related diseases of human.
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Affiliation(s)
- Juan Wang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Wenkang Wang
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi City), Zunyi Medical University, Zunyi, China
| | - Hui Wang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
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The anion exchanger PAT-1 (Slc26a6) does not participate in oxalate or chloride transport by mouse large intestine. Pflugers Arch 2020; 473:95-106. [PMID: 33205229 DOI: 10.1007/s00424-020-02495-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/23/2020] [Accepted: 11/10/2020] [Indexed: 01/20/2023]
Abstract
The membrane-bound transport proteins responsible for oxalate secretion across the large intestine remain unidentified. The apical chloride/bicarbonate (Cl-/HCO3-) exchanger encoded by Slc26a6, known as PAT-1 (putative anion transporter 1), is a potential candidate. In the small intestine, PAT-1 makes a major contribution to oxalate secretion but whether this role extends into the large intestine has not been directly tested. Using the PAT-1 knockout (KO) mouse, we compared the unidirectional absorptive ([Formula: see text]) and secretory ([Formula: see text]) flux of oxalate and Cl- across cecum, proximal colon, and distal colon from wild-type (WT) and KO mice in vitro. We also utilized the non-specific inhibitor DIDS (4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid) to confirm a role for PAT-1 in WT large intestine and (in KO tissues) highlight any other apical anion exchangers involved. Under symmetrical, short-circuit conditions the cecum and proximal colon did not transport oxalate on a net basis, whereas the distal colon supported net secretion. We found no evidence for the participation of PAT-1, or indeed any other DIDS-sensitive transport mechanism, in oxalate or Cl- by the large intestine. Most unexpectedly, mucosal DIDS concurrently stimulated [Formula: see text] and [Formula: see text] by 25-68% across each segment without impacting net transport. For the colon, these changes were directly proportional to increased transepithelial conductance suggesting this response was the result of bidirectional paracellular flux. In conclusion, PAT-1 does not contribute to oxalate or Cl- transport by the large intestine, and we urge caution when using DIDS with mouse colonic epithelium.
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24
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Sharma AP, Burton J, Filler G, Dave S. Current update and future directions on gut microbiome and nephrolithiasis. Indian J Urol 2020; 36:262-269. [PMID: 33376261 PMCID: PMC7759161 DOI: 10.4103/iju.iju_20_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/31/2020] [Indexed: 01/21/2023] Open
Abstract
The incidence of nephrolithiasis is increasing worldwide. Understanding how gut microbiome influences oxalate homeostasis has the potential to offer new strategies to prevent nephrolithiasis. The literature was reviewed to gather the evidence on the association between gut microbiome, hyperoxaluria and nephrolithiasis, and to identify the therapeutic interventions focused on the gut microbiome that could decrease hyperoxaluria and prevent nephrolithiasis. Gut microbiome is constituted by a plethora of microbiota including Oxalobacter formigenes (Oxf) and lactobacilli. Oxf can degrade dietary oxalate and induce enteral oxalate secretion. Animal studies suggested an association between oral Oxf supplementation and a decrease in hyperoxaluria. However, human studies have showed inconsistent results. Oral supplementation of lactobacilli did not show benefit in decreasing the hyperoxaluria. Antibiotic exposure, by affecting the gut microbiome, has been associated with an increase in nephrolithiasis. In vivo studies suggest fecal transplantation as a potential treatment option for reducing nephrolithiasis, but needs further evaluation in clinical studies. The current evidence suggests an association between gut microbiome and nephrolithiasis. However, the strategies focused on modulating gut microbiome for decreasing hyperoxaluria and preventing nephrolithiasis need further research. Judicious use of antibiotics in those predisposed to nephrolithiasis offers a preventative strategy for decreasing nephrolithiasis.
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Affiliation(s)
- Ajay P Sharma
- Department of Pediatrics, London Health Sciences Centre, Western University, London, Canada.,Division of Nephrology, London Health Sciences Centre, Western University, London, Canada
| | - Jeremy Burton
- Division of Urology, London Health Sciences Centre, Western University, London, Canada
| | - Guido Filler
- Department of Pediatrics, London Health Sciences Centre, Western University, London, Canada
| | - Sumit Dave
- Division of Urology, London Health Sciences Centre, Western University, London, Canada
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25
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Dietary Oxalate Intake and Kidney Outcomes. Nutrients 2020; 12:nu12092673. [PMID: 32887293 PMCID: PMC7551439 DOI: 10.3390/nu12092673] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 08/25/2020] [Accepted: 08/30/2020] [Indexed: 12/16/2022] Open
Abstract
Oxalate is both a plant-derived molecule and a terminal toxic metabolite with no known physiological function in humans. It is predominantly eliminated by the kidneys through glomerular filtration and tubular secretion. Regardless of the cause, the increased load of dietary oxalate presented to the kidneys has been linked to different kidney-related conditions and injuries, including calcium oxalate nephrolithiasis, acute and chronic kidney disease. In this paper, we review the current literature on the association between dietary oxalate intake and kidney outcomes.
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26
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Geraghty R, Wood K, Sayer JA. Calcium oxalate crystal deposition in the kidney: identification, causes and consequences. Urolithiasis 2020; 48:377-384. [PMID: 32719990 PMCID: PMC7496019 DOI: 10.1007/s00240-020-01202-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 07/17/2020] [Indexed: 02/06/2023]
Abstract
Calcium oxalate (CaOx) crystal deposition within the tubules is often a perplexing finding on renal biopsy of both native and transplanted kidneys. Understanding the underlying causes may help diagnosis and future management. The most frequent cause of CaOx crystal deposition within the kidney is hyperoxaluria. When this is seen in native kidney biopsy, primary hyperoxaluria must be considered and investigated further with biochemical and genetic tests. Secondary hyperoxaluria, for example due to enteric hyperoxaluria following bariatric surgery, ingested ethylene glycol or vitamin C overdose may also cause CaOx deposition in native kidneys. CaOx deposition is a frequent finding in renal transplant biopsy, often as a consequence of acute tubular necrosis and is associated with poorer long-term graft outcomes. CaOx crystal deposition in the renal transplant may also be secondary to any of the causes associated with this phenotype in the native kidney. The pathophysiology underlying CaOx deposition is complex but this histological phenotype may indicate serious underlying pathology and should always warrant further investigation.
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Affiliation(s)
- R Geraghty
- Renal Services, The Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK
| | - K Wood
- Histopathology Department, The Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE1 4LP, UK
| | - J A Sayer
- Renal Services, The Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK. .,Translational and Clinical Research Institute, Faculty of Medical Sciences, International Centre for Life, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK. .,NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne, UK.
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27
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Neumeier LI, Thomson RB, Reichel M, Eckardt KU, Aronson PS, Knauf F. Enteric Oxalate Secretion Mediated by Slc26a6 Defends against Hyperoxalemia in Murine Models of Chronic Kidney Disease. J Am Soc Nephrol 2020; 31:1987-1995. [PMID: 32660969 DOI: 10.1681/asn.2020010105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/01/2020] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND A state of oxalate homeostasis is maintained in patients with healthy kidney function. However, as GFR declines, plasma oxalate (Pox) concentrations start to rise. Several groups of researchers have described augmentation of oxalate secretion in the colon in models of CKD, but the oxalate transporters remain unidentified. The oxalate transporter Slc26a6 is a candidate for contributing to the extrarenal clearance of oxalate via the gut in CKD. METHODS Feeding a diet high in soluble oxalate or weekly injections of aristolochic acid induced CKD in age- and sex-matched wild-type and Slc26a6 -/- mice. qPCR, immunohistochemistry, and western blot analysis assessed intestinal Slc26a6 expression. An oxalate oxidase assay measured fecal and Pox concentrations. RESULTS Fecal oxalate excretion was enhanced in wild-type mice with CKD. This increase was abrogated in Slc26a6 -/- mice associated with a significant elevation in plasma oxalate concentration. Slc26a6 mRNA and protein expression were greatly increased in the intestine of mice with CKD. Raising Pox without inducing kidney injury did not alter intestinal Slc26a6 expression, suggesting that changes associated with CKD regulate transporter expression rather than elevations in Pox. CONCLUSIONS Slc26a6-mediated enteric oxalate secretion is critical in decreasing the body burden of oxalate in murine CKD models. Future studies are needed to address whether similar mechanisms contribute to intestinal oxalate elimination in humans to enhance extrarenal oxalate clearance.
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Affiliation(s)
- Laura I Neumeier
- Department of Nephrology and Hypertension, Friedrich Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Robert B Thomson
- Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut
| | - Martin Reichel
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Kai-Uwe Eckardt
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Peter S Aronson
- Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut.,Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Felix Knauf
- Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut .,Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
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28
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Whittamore JM. The teleost fish intestine is a major oxalate-secreting epithelium. J Exp Biol 2020; 223:jeb216895. [PMID: 32122927 DOI: 10.1242/jeb.216895] [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: 10/17/2019] [Accepted: 02/19/2020] [Indexed: 11/20/2022]
Abstract
Oxalate is a common constituent of kidney stones, but the mechanism of its transport across epithelia is not well understood. With prior research on the role of the intestine focused on mammals, the present study considered oxalate handling by teleost fish. Given the osmotic challenge of seawater (SW), marine teleosts have limited scope for urinary oxalate excretion relative to freshwater (FW) taxa. The marine teleost intestine was hypothesized as the principal route for oxalate elimination, thus demanding epithelial secretion. To test this, intestinal 14C-oxalate flux was compared between FW- and SW-acclimated sailfin molly (Poecilia latipinna). In SW, oxalate was secreted at remarkable rates (367.90±22.95 pmol cm-2 h-1), which were similar following FW transfer (387.59±27.82 pmol cm-2 h-1), implying no regulation by salinity. Nevertheless, this ability to secrete oxalate at rates 15-19 times higher than the mammalian small intestine supports this proposal of the teleost gut as a major, previously unrecognized excretory pathway.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, P.O. Box 100275, 1600 SW Archer Road, Gainesville, FL 32610, USA
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29
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Ormanji MS, Rodrigues FG, Heilberg IP. Dietary Recommendations for Bariatric Patients to Prevent Kidney Stone Formation. Nutrients 2020; 12:nu12051442. [PMID: 32429374 PMCID: PMC7284744 DOI: 10.3390/nu12051442] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/09/2020] [Accepted: 05/13/2020] [Indexed: 12/12/2022] Open
Abstract
Bariatric surgery (BS) is one of the most common and efficient surgical procedures for sustained weight loss but is associated with long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis, attributed to urinary metabolic changes resultant from low urinary volume, hypocitraturia and hyperoxaluria. The underlying mechanisms responsible for hyperoxaluria, the most common among all metabolic disturbances, may comprise increased intestinal oxalate absorption consequent to decreased calcium intake or increased dietary oxalate, changes in the gut microbiota, fat malabsorption and altered intestinal oxalate transport. In the current review, the authors present a mechanistic overview of changes found after BS and propose dietary recommendations to prevent the risk of urinary stone formation, focusing on the role of dietary oxalate, calcium, citrate, potassium, protein, fat, sodium, probiotics, vitamins D, C, B6 and the consumption of fluids.
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Affiliation(s)
- Milene S. Ormanji
- Nephrology Division, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil; (M.S.O.); (F.G.R.)
| | - Fernanda G. Rodrigues
- Nephrology Division, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil; (M.S.O.); (F.G.R.)
- Department of Nutrition, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Ita P. Heilberg
- Nephrology Division, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil; (M.S.O.); (F.G.R.)
- Department of Nutrition, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
- Correspondence: ; Tel.: +55-(11)-5576-4848 (ext. 2465)
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30
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Arvans D, Alshaikh A, Bashir M, Weber C, Hassan H. Activation of the PKA signaling pathway stimulates oxalate transport by human intestinal Caco2-BBE cells. Am J Physiol Cell Physiol 2020; 318:C372-C379. [PMID: 31825656 PMCID: PMC7052606 DOI: 10.1152/ajpcell.00135.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 12/04/2019] [Accepted: 12/04/2019] [Indexed: 02/06/2023]
Abstract
Most kidney stones are composed of calcium oxalate, and small increases in urine oxalate enhance the stone risk. The mammalian intestine plays a crucial role in oxalate homeostasis, and we had recently reported that Oxalobacter-derived factors stimulate oxalate transport by human intestinal Caco2-BBE (C2) cells through PKA activation. We therefore evaluated whether intestinal oxalate transport is directly regulated by activation of the PKA signaling pathway. To this end, PKA was activated with forskolin and IBMX (F/I). F/I significantly stimulated (3.7-fold) [14C]oxalate transport by C2 cells [≥49% of which is mediated by the oxalate transporter SLC26A6 (A6)], an effect completely blocked by the PKA inhibitor H89, indicating that it is PKA dependent. PKA stimulation of intestinal oxalate transport is not cell line specific, since F/I similarly stimulated oxalate transport by the human intestinal T84 cells. F/I significantly increased (2.5-fold) A6 surface protein expression by use of immunocytochemistry. Assessing [14C]oxalate transport as a function of increasing [14C]oxalate concentration in the flux medium showed that the observed stimulation is due to a F/I-induced increase (1.8-fold) in Vmax and reduction (2-fold) in Km. siRNA knockdown studies showed that significant components of the observed stimulation are mediated by A6 and SLC26A2 (A2). Besides enhancing A6 surface protein expression, it is also possible that the observed stimulation is due to PKA-induced enhanced A6 and/or A2 transport activity in view of the reduced Km. We conclude that PKA activation positively regulates oxalate transport by intestinal epithelial cells and that PKA agonists might therapeutically impact hyperoxalemia, hyperoxaluria, and related kidney stones.
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Affiliation(s)
- Donna Arvans
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Altayeb Alshaikh
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Mohamed Bashir
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Christopher Weber
- Department of Pathology, The University of Chicago, Chicago, Illinois
| | - Hatim Hassan
- Department of Medicine, The University of Chicago, Chicago, Illinois
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Abstract
The recognition that intestinal microbiota exert profound effects on human health has led to major advances in our understanding of disease processes. Studies over the past 20 years have shown that host components, including components of the host immune system, shape the microbial community. Pathogenic alterations in commensal microorganisms contribute to disease manifestations that are generally considered to be noncommunicable, such as inflammatory bowel disease, diabetes mellitus and liver disease, through a variety of mechanisms, including effects on host immunity. More recent studies have shed new light on how the immune system and microbiota might also drive the pathogenesis of renal disorders. In this Review, we discuss the latest insights into the mechanisms regulating the microbiome composition, with a focus both on genetics and environmental factors, and describe how commensal microorganisms calibrate innate and adaptive immune responses to affect the activation threshold for pathogenic stimulations. We discuss the mechanisms that lead to intestinal epithelial barrier inflammation and the relevance of certain bacteria to the pathogenesis of two common kidney-based disorders: hypertension and renal stone disease. Limitations of current approaches to microbiota research are also highlighted, emphasizing the need to move beyond studies of correlation to causation.
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Affiliation(s)
- Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - J Richard Brewer
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA. .,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.
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32
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Touré A. Importance of SLC26 Transmembrane Anion Exchangers in Sperm Post-testicular Maturation and Fertilization Potential. Front Cell Dev Biol 2019; 7:230. [PMID: 31681763 PMCID: PMC6813192 DOI: 10.3389/fcell.2019.00230] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/26/2019] [Indexed: 12/17/2022] Open
Abstract
In mammals, sperm cells produced within the testis are structurally differentiated but remain immotile and are unable to fertilize the oocyte unless they undergo a series of maturation events during their transit in the male and female genital tracts. This post-testicular functional maturation is known to rely on the micro-environment of both male and female genital tracts, and is tightly controlled by the pH of their luminal milieus. In particular, within the epididymis, the establishment of a low bicarbonate (HCO3–) concentration contributes to luminal acidification, which is necessary for sperm maturation and subsequent storage in a quiescent state. Following ejaculation, sperm is exposed to the basic pH of the female genital tract and bicarbonate (HCO3–), calcium (Ca2+), and chloride (Cl–) influxes induce biochemical and electrophysiological changes to the sperm cells (cytoplasmic alkalinization, increased cAMP concentration, and protein phosphorylation cascades), which are indispensable for the acquisition of fertilization potential, a process called capacitation. Solute carrier 26 (SLC26) members are conserved membranous proteins that mediate the transport of various anions across the plasma membrane of epithelial cells and constitute important regulators of pH and HCO3– concentration. Most SLC26 members were shown to physically interact and cooperate with the cystic fibrosis transmembrane conductance regulator channel (CFTR) in various epithelia, mainly by stimulating its Cl– channel activity. Among SLC26 members, the function of SLC26A3, A6, and A8 were particularly investigated in the male genital tract and the sperm cells. In this review, we will focus on SLC26s contributions to ionic- and pH-dependent processes during sperm post-testicular maturation. We will specify the current knowledge regarding their functions, based on data from the literature generated by means of in vitro and in vivo studies in knock-out mouse models together with genetic studies of infertile patients. We will also discuss the limits of those studies, the current research gaps and identify some key points for potential developments in this field.
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Affiliation(s)
- Aminata Touré
- INSERM U1016, Centre National de la Recherche Scientifique, UMR 8104, Institut Cochin, Université de Paris, Paris, France
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33
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Hatch M. Induction of enteric oxalate secretion by Oxalobacter formigenes in mice does not require the presence of either apical oxalate transport proteins Slc26A3 or Slc26A6. Urolithiasis 2019; 48:1-8. [PMID: 31201468 DOI: 10.1007/s00240-019-01144-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 06/09/2019] [Indexed: 12/20/2022]
Abstract
Oxalobacter sp. promotion of enteric oxalate excretion, correlating with reductions in urinary oxalate excretion, was previously reported in rats and mice, but the mechanistic basis for this affect has not been described. The main objective of the present study was to determine whether the apical oxalate transport proteins, PAT1 (slc26a6) and DRA (slc26a3), are involved in mediating the Oxalobacter-induced net secretory flux across colonized mouse cecum and distal colon. We measured unidirectional and net fluxes of oxalate across tissues removed from colonized PAT1 and DRA knockout (KO) mice and also across two double knockout (dKO) mouse models with primary hyperoxaluria, type 1 (i.e., deficient in alanine-glyoxylate aminotransferase; AGT KO), including PAT1/AGT dKO and DRA/AGT dKO mice compared to non-colonized mice. In addition, urinary oxalate excretion was measured before and after the colonization procedure. The results demonstrate that Oxalobacter can induce enteric oxalate excretion in the absence of either apical oxalate transporter and urinary oxalate excretion was reduced in all colonized genotypes fed a 1.5% oxalate-supplemented diet. We conclude that there are other, as yet unidentified, oxalate transporters involved in mediating the directional changes in oxalate transport across the Oxalobacter-colonized mouse large intestine.
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Affiliation(s)
- Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
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34
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Hennessey DB, Kinnear N, Rice G, Curry D, Woolsey S, Duggan B. Compliance in patients with dietary hyperoxaluria: A cohort study and systematic review. Asian J Urol 2019; 6:200-207. [PMID: 31061807 PMCID: PMC6488745 DOI: 10.1016/j.ajur.2018.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 11/09/2017] [Accepted: 12/06/2017] [Indexed: 11/04/2022] Open
Abstract
Objective Hyperoxaluria leads to calcium oxalate crystal formation and subsequent urolithiasis. This study aims to analyse the effect of treatment compliance in hyperoxaluria, firstly by analysis of patients with non-primary hyperoxaluria and secondly via systematic review in patients with any hyperoxaluria. Methods In a retrospective cohort study, adults with non-primary hyperoxaluria managed with dietary counselling in 2013 were enrolled. Twenty-four-hour (24 h) urine collections initially and at 6 months were obtained. Compliance was assessed by self-reported dietary compliance and 24 h urinary volume >2 L. Patients were followed for 24 months. Primary outcomes were urinary oxalate and calcium 24 h load at 6 months, and urolithiasis-related procedural rates at 24 months. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compatible systematic review of compliance among hyperoxaluric patients was performed. Results In the cohort study, of 19 eligible patients (4 female) with median age 52 years, 10 (53%) were considered compliant. Compared with the non-compliant group, these patients had significantly increased subsequent 24 h urinary volume (2250 mL vs. 1600 mL; p = 0.008) and lower procedural rates (10% vs. 56%; p = 0.033). Subsequent 24 h urinary oxalate load was non-significantly lower in compliant patients. Systematic review regarding compliance in hyperoxaluric patients revealed five studies. Only one utilised dietary counselling or analysed compliant vs. non-compliant patients, finding no difference. None examined the effect of compliance on procedural rates. Conclusion Hyperoxaluria is an important cause of recurrent urolithiasis. Increasing fluid intake and reducing dietary oxalate reduce the risk of operative intervention and remain fundamental to the treatment of hyperoxaluria.
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Affiliation(s)
- Derek B Hennessey
- Department of Urology, Belfast City Hospital, Belfast, United Kingdom.,Department of Urology, Austin Hospital, Melbourne, Australia
| | - Ned Kinnear
- Department of Urology, Austin Hospital, Melbourne, Australia
| | - Gilbert Rice
- Department of Urology, Belfast City Hospital, Belfast, United Kingdom
| | - David Curry
- Department of Urology, Belfast City Hospital, Belfast, United Kingdom
| | - Siobhan Woolsey
- Department of Urology, Belfast City Hospital, Belfast, United Kingdom
| | - Brian Duggan
- Department of Urology, Belfast City Hospital, Belfast, United Kingdom.,Department of Urology, Ulster Hospital, Belfast, United Kingdom
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Anbazhagan AN, Priyamvada S, Borthakur A, Saksena S, Gill RK, Alrefai WA, Dudeja PK. miR-125a-5p: a novel regulator of SLC26A6 expression in intestinal epithelial cells. Am J Physiol Cell Physiol 2019; 317:C200-C208. [PMID: 31042422 DOI: 10.1152/ajpcell.00068.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Putative anion transporter 1 (PAT1, SLC26A6), an intestinal epithelial Cl-/ HCO3- exchanger, also plays a key role in oxalate homeostasis via mediating intestinal oxalate secretion. Indeed, Slc26a6-null mice showed defect in intestinal oxalate secretion and high incidence of kidney stones. Recent emergence of PAT-1 as a novel therapeutic target for nephrolithiasis warrants detailed understanding of the mechanisms of PAT-1 regulation in health and disease. Therefore, we investigated the regulation of PAT-1 expression by microRNAs (miRNA), as they have been shown to play key role in modulating expression of other ion transporters. In silico analysis of PAT-1 3'-untranslated region (UTR) revealed potential binding sites for several miRNAs, suggesting the role of miRNAs in modulating PAT1 expression. miRNAs showing highest context scores (125a-5p, 339-5p, 423-5p, 485-5p, and 501-3p) were selected as candidates for their effects on the activity of a 263-bp PAT-1 3'-untranslated region (UTR) fragment cloned into pmirGLO vector upstream of luciferase. The 3'-UTR activity was measured by dual luciferase reporter assay in Caco-2, T-84, HT-29, and SK-CO15 cells. Transient transfection of PAT-1 3'-UTR significantly decreased the relative luciferase activity compared with the empty vector suggesting binding of potential miRNA(s) to the PAT-1 3'-UTR. Among all the selected candidates, cotransfection with miRNA mimics 125a-5p and 423-5p further decreased PAT-1 3'-UTR activity. Furthermore, increasing miR-125a-5p abundance via mimic transfection in Caco-2 cells decreased both mRNA and protein levels of PAT-1. Our results demonstrate a novel regulatory mechanism of intestinal PAT-1 expression via miR-125a-5p that could be of therapeutic importance in disorders associated with decreased PAT-1 expression and function.
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Affiliation(s)
- Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Alip Borthakur
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois.,Jesse Brown VA Medical Center , Chicago, Illinois
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Waddah A Alrefai
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois.,Jesse Brown VA Medical Center , Chicago, Illinois
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois.,Jesse Brown VA Medical Center , Chicago, Illinois
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Seidler U, Nikolovska K. Slc26 Family of Anion Transporters in the Gastrointestinal Tract: Expression, Function, Regulation, and Role in Disease. Compr Physiol 2019; 9:839-872. [DOI: 10.1002/cphy.c180027] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Stern JM, Urban‐Maldonado M, Usyk M, Granja I, Schoenfeld D, Davies KP, Agalliu I, Asplin J, Burk R, Suadicani SO. Fecal transplant modifies urine chemistry risk factors for urinary stone disease. Physiol Rep 2019; 7:e14012. [PMID: 30789675 PMCID: PMC6383111 DOI: 10.14814/phy2.14012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/01/2019] [Accepted: 02/03/2019] [Indexed: 01/04/2023] Open
Abstract
Urinary stone disease (USD) is a major health concern. There is a need for new treatment modalities. Recently, our group provided evidence for an association between the GMB composition and USD. The accessibility of the Gut Microbiome (GMB) makes it an attractive target for investigation and therefore, in these studies we have evaluated the extent to which the whole gut microbial community in fecal transplants can affect urinary stone risk parameters in an animal model. Fresh fecal pellets were collected from Zucker lean rats, homogenized in PBS (100 mg/mL), filtered through a 70 μm strainer and then orally gavaged into C57BL/6NTac germ-free mice. Twenty-four hours urine collections and GMB analysis were performed over time for 1 month. Kidney and gut tissue were harvested from transplanted mice for western blot analysis of expression levels of the Slc26a6 transporter involved in oxalate balance. Urinary calcium decreased after fecal transplant by 55% (P < 0.001). Urinary oxalate levels were on average 24% lower than baseline levels (P < 0.001). Clostridiaceae family was negatively correlated with urinary oxalate at 4 weeks after transplant (r = -0.83, P < 0.01). There was a 0.6 unit average increase in urinary pH from a baseline of 5.85 (SE ± 0.028) to 6.49 (SE ± 0.04) (P < 0.001) after transplant. There was a concomitant 29% increase in gastrointestinal alkali absorption (P < 0.001) 4-weeks after fecal transplant. Slc26a6 expression increased by 90% in the cecum after transplant. Our results suggest that the gut microbiome may impact metabolism, alters urinary chemistry, and thereby may influence USD; the accessibility of the GMB can potentially be leveraged for therapeutic interventions.
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Affiliation(s)
- Joshua M. Stern
- Department of UrologyAlbert Einstein College of MedicineBronxNew York
| | | | - Mykhaylo Usyk
- Department of MicrobiologyAlbert Einstein College of MedicineBronxNew York
| | | | - Daniel Schoenfeld
- Department of UrologyAlbert Einstein College of MedicineBronxNew York
| | - Kelvin P. Davies
- Department of UrologyAlbert Einstein College of MedicineBronxNew York
| | - Ilir Agalliu
- Department of EpidemiologyAlbert Einstein College of MedicineBronxNew York
| | | | - Robert Burk
- Department of MicrobiologyAlbert Einstein College of MedicineBronxNew York
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Bashir M, Meddings J, Alshaikh A, Jung D, Le K, Amin R, Ratakonda S, Sharma S, Granja I, Satti M, Asplin J, Hassan H. Enhanced gastrointestinal passive paracellular permeability contributes to the obesity-associated hyperoxaluria. Am J Physiol Gastrointest Liver Physiol 2019; 316:G1-G14. [PMID: 30307745 PMCID: PMC6383380 DOI: 10.1152/ajpgi.00266.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Most kidney stones (KS) are composed of calcium oxalate and small increases in urine oxalate enhance the stone risk. Obesity is a risk factor for KS, and urinary oxalate excretion increases with increased body size. We previously established the obese ob/ob ( ob) mice as a model (3.3-fold higher urine oxalate) to define the pathogenesis of obesity-associated hyperoxaluria (OAH). The purpose of this study was to test the hypothesis that the obesity-associated enhanced small intestinal paracellular permeability contributes to OAH by increasing passive paracellular intestinal oxalate absorption. ob Mice have significantly higher jejunal (1.6-fold) and ileal (1.4-fold) paracellular oxalate absorption ex vivo and significantly higher (5-fold) urine [13C]oxalate following oral gavage with [13C]oxalate, indicating increased intestinal oxalate absorption in vivo. The observation of higher oxalate absorption in vivo compared with ex vivo suggests the possibility of increased paracellular permeability along the entire gut. Indeed, ob mice have significantly higher fractions of the administered sucrose (1.7-fold), lactulose (4.4-fold), and sucralose (3.1-fold) excreted in the urine, reflecting increased gastric, small intestinal, and colonic paracellular permeability, respectively. The ob mice have significantly reduced gastrointestinal occludin, zonula occludens-1, and claudins-1 and -3 mRNA and total protein expression. Proinflammatory cytokines and oxidative stress, which are elevated in obesity, significantly enhanced paracellular intestinal oxalate absorption in vitro and ex vivo. We conclude that obese mice have significantly higher intestinal oxalate absorption and enhanced gastrointestinal paracellular permeability in vivo, which would likely contribute to the pathogenesis of OAH, since there is a transepithelial oxalate concentration gradient to drive paracellular intestinal oxalate absorption. NEW & NOTEWORTHY This study shows that the obese ob/ob mice have significantly increased gastrointestinal paracellular oxalate absorption and remarkably enhanced paracellular permeability along the entire gut in vivo, which are likely mediated by the obesity-associated increased systemic and intestinal inflammation and oxidative stress. A transepithelial oxalate concentration gradient driving gastrointestinal paracellular oxalate absorption exists, and therefore, our novel findings likely contribute to the hyperoxaluria observed in the ob/ob mice and hence to the pathogenesis of obesity-associated hyperoxaluria.
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Affiliation(s)
- Mohamed Bashir
- 1Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Jon Meddings
- 2Department of Surgery, University of Calgary, Calgary, Alberta, Canada
| | - Altayeb Alshaikh
- 1Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Daniel Jung
- 1Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Kim Le
- 2Department of Surgery, University of Calgary, Calgary, Alberta, Canada
| | - Ruhul Amin
- 1Department of Medicine, The University of Chicago, Chicago, Illinois
| | | | - Sapna Sharma
- 1Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Ignacio Granja
- 3Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois
| | - Mustafa Satti
- 1Department of Medicine, The University of Chicago, Chicago, Illinois
| | - John Asplin
- 3Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois
| | - Hatim Hassan
- 1Department of Medicine, The University of Chicago, Chicago, Illinois
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Whittamore JM, Stephens CE, Hatch M. Absence of the sulfate transporter SAT-1 has no impact on oxalate handling by mouse intestine and does not cause hyperoxaluria or hyperoxalemia. Am J Physiol Gastrointest Liver Physiol 2019; 316:G82-G94. [PMID: 30383413 PMCID: PMC6383384 DOI: 10.1152/ajpgi.00299.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The anion exchanger SAT-1 [sulfate anion transporter 1 (Slc26a1)] is considered an important regulator of oxalate and sulfate homeostasis, but the mechanistic basis of these critical roles remain undetermined. Previously, characterization of the SAT-1-knockout (KO) mouse suggested that the loss of SAT-1-mediated oxalate secretion by the intestine was responsible for the hyperoxaluria, hyperoxalemia, and calcium oxalate urolithiasis reportedly displayed by this model. To test this hypothesis, we compared the transepithelial fluxes of 14C-oxalate, 35SO42- , and 36Cl- across isolated, short-circuited segments of the distal ileum, cecum, and distal colon from wild-type (WT) and SAT-1-KO mice. The absence of SAT-1 did not impact the transport of these anions by any part of the intestine examined. Additionally, SAT-1-KO mice were neither hyperoxaluric nor hyperoxalemic. Instead, 24-h urinary oxalate excretion was almost 50% lower than in WT mice. With no contribution from the intestine, we suggest that this may reflect the loss of SAT-1-mediated oxalate efflux from the liver. SAT-1-KO mice were, however, profoundly hyposulfatemic, even though there were no changes to intestinal sulfate handling, and the renal clearances of sulfate and creatinine indicated diminished rates of sulfate reabsorption by the proximal tubule. Aside from this distinct sulfate phenotype, we were unable to reproduce the hyperoxaluria, hyperoxalemia, and urolithiasis of the original SAT-1-KO model. In conclusion, oxalate and sulfate transport by the intestine were not dependent on SAT-1, and we found no evidence supporting the long-standing hypothesis that intestinal SAT-1 contributes to oxalate and sulfate homeostasis. NEW & NOTEWORTHY SAT-1 is a membrane-bound transport protein expressed in the intestine, liver, and kidney, where it is widely considered essential for the excretion of oxalate, a potentially toxic waste metabolite. Previously, calcium oxalate kidney stone formation by the SAT-1-knockout mouse generated the hypothesis that SAT-1 has a major role in oxalate excretion via the intestine. We definitively tested this proposal and found no evidence for SAT-1 as an intestinal anion transporter contributing to oxalate homeostasis.
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Affiliation(s)
- Jonathan M. Whittamore
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida
| | - Christine E. Stephens
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida
| | - Marguerite Hatch
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida
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Sex-independent expression of chloride/formate exchanger Cfex (Slc26a6) in rat pancreas, small intestine, and liver, and male-dominant expression in kidneys. Arh Hig Rada Toksikol 2018; 69:286-303. [PMID: 30864378 DOI: 10.2478/aiht-2018-69-3157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/01/2018] [Indexed: 01/03/2023] Open
Abstract
Chloride/formate exchanger (CFEX; SLC26A6) mediates oxalate transport in various mammalian organs. Studies in Cfex knockout mice indicated its possible role in development of male-dominant hyperoxaluria and oxalate urolithiasis. Rats provide an important model for studying this pathophysiological condition, but data on Cfex (rCfex) localisation and regulation in their organs are limited. Here we applied the RT-PCR and immunochemical methods to investigate rCfex mRNA and protein expression and regulation by sex hormones in the pancreas, small intestine, liver, and kidneys from intact prepubertal and adult as well as gonadectomised adult rats treated with sex hormones. rCfex cDNA-transfected HEK293 cells were used to confirm the specificity of the commercial anti-CFEX antibody. Various biochemical parameters were measured in 24-h urine collected in metabolic cages. rCfex mRNA and related protein expression varied in all tested organs. Sex-independent expression of the rCfex protein was detected in pancreatic intercalated ducts (apical domain), small intestinal enterocytes (brush-border membrane; duodenum > jejunum > ileum), and hepatocytes (canalicular membrane). In kidneys, the rCfex protein was immunolocalised to the proximal tubule brush-border with segment-specific pattern (S1=S2<S3), and both rCfex mRNA and protein expression exhibited male-dominant sex differences driven by stimulatory effects of androgens after puberty. However, urinary oxalate excretion was unrelated to renal rCfex protein expression. While the effect of male-dominant expression of rCfex in renal proximal tubules on urine oxalate excretion remains unknown, its expression in the hepatocyte canalicular membrane may be a pathway of oxalate elimination via bile.
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Knauf F, Velazquez H, Pfann V, Jiang Z, Aronson PS. Characterization of renal NaCl and oxalate transport in Slc26a6 -/- mice. Am J Physiol Renal Physiol 2018; 316:F128-F133. [PMID: 30427220 DOI: 10.1152/ajprenal.00309.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The apical membrane Cl-/oxalate exchanger SLC26A6 has been demonstrated to play a role in proximal tubule NaCl transport based on studies in microperfused tubules. The present study is directed at characterizing the role of SLC26A6 in NaCl homeostasis in vivo under physiological conditions. Free-flow micropuncture studies revealed that volume and Cl- absorption were similar in surface proximal tubules of wild-type and Slc26a6-/- mice. Moreover, the increments in urine flow rate and sodium excretion following thiazide and furosemide infusion were identical in wild-type and Slc26a6-/- mice, indicating no difference in NaCl delivery out of the proximal tubule. The absence of an effect of deletion of SLC26A6 on NaCl homeostasis was further supported by the absence of lower blood pressure in Slc26a6-/- compared with wild-type mice on normal or low-salt diets. Moreover, raising plasma and urine oxalate by feeding mice a diet enriched in soluble oxalate did not affect mean blood pressure. In contrast to the lack of effect of SLC26A6 deletion on NaCl homeostasis, fractional excretion of oxalate was reduced from 1.6 in wild-type mice to 0.7 in Slc26a6-/- mice. We conclude that, although SLC26A6 is dispensable for renal NaCl homeostasis, it is required for net renal secretion of oxalate.
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Affiliation(s)
- Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin , Germany.,Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
| | - Heino Velazquez
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
| | - Victoria Pfann
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin , Germany.,Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
| | - Zhirong Jiang
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
| | - Peter S Aronson
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut.,Department of Cellular and Molecular Physiology, Yale University School of Medicine , New Haven, Connecticut
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Jung D, Alshaikh A, Ratakonda S, Bashir M, Amin R, Jeon S, Stevens J, Sharma S, Ahmed W, Musch M, Hassan H. Adenosinergic signaling inhibits oxalate transport by human intestinal Caco2-BBE cells through the A 2B adenosine receptor. Am J Physiol Cell Physiol 2018; 315:C687-C698. [PMID: 30020825 DOI: 10.1152/ajpcell.00024.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Most kidney stones (KS) are composed of calcium oxalate, and small increases in urine oxalate affect the stone risk. Intestinal oxalate secretion mediated by anion exchanger SLC26A6 (PAT1) plays a crucial role in limiting net absorption of ingested oxalate, thereby preventing hyperoxaluria and related KS, reflecting the importance of understanding regulation of intestinal oxalate transport. We previously showed that ATP and UTP inhibit oxalate transport by human intestinal Caco2-BBE cells (C2). Since ATP is rapidly degraded to adenosine (ADO), we examined whether intestinal oxalate transport is regulated by ADO. We measured [14C]oxalate uptake in the presence of an outward Cl gradient as an assay of Cl-oxalate exchange activity, ≥49% of which is PAT1-mediated in C2 cells. We found that ADO significantly inhibited oxalate transport by C2 cells, an effect completely blocked by the nonselective ADO receptor antagonist 8- p-sulfophenyltheophylline. ADO also significantly inhibited oxalate efflux by C2 cells, which is important since PAT1 mediates oxalate efflux in vivo. Using pharmacological antagonists and A2B adenosine receptor (A2B AR) siRNA knockdown studies, we observed that ADO inhibits oxalate transport through the A2B AR, phospholipase C, and PKC. ADO inhibits oxalate transport by reducing PAT1 surface expression as shown by biotinylation studies. We conclude that ADO inhibits oxalate transport by lowering PAT1 surface expression in C2 cells through signaling pathways including the A2B AR, PKC, and phospholipase C. Given higher ADO levels and overexpression of the A2B AR in inflammatory bowel disease (IBD), our findings have potential relevance to pathophysiology of IBD-associated hyperoxaluria and related KS.
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Affiliation(s)
- Daniel Jung
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Altayeb Alshaikh
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | | | - Mohamed Bashir
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Ruhul Amin
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sohee Jeon
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Jan Stevens
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sapna Sharma
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Wahaj Ahmed
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Mark Musch
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Hatim Hassan
- Department of Medicine, The University of Chicago , Chicago, Illinois
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Jiang H, Pokhrel G, Chen Y, Wang T, Yin C, Liu J, Wang S, Liu Z. High expression of SLC26A6 in the kidney may contribute to renal calcification via an SLC26A6-dependent mechanism. PeerJ 2018; 6:e5192. [PMID: 30002986 PMCID: PMC6034601 DOI: 10.7717/peerj.5192] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 06/18/2018] [Indexed: 12/12/2022] Open
Abstract
Background Solute-linked carrier 26 gene family 6 (SLC26A6), which is mainly expressed in intestines and kidneys, is a multifunctional anion transporter crucial in the transport of oxalate anions. This study aimed to investigate the role of kidney SLC26A6 in urolithiasis. Methods Patients were divided into two groups: stone formers and nonstone formers. Samples were collected from patients following nephrectomy. Lentivirus with Slc26a6 (lentivirus-Slc26a6) sequence and lentivirus with siRNA-Slc26a6 (lentivirus-siRNA-Slc26a6) sequence were transfected into rats’ kidneys respectively and Slc26a6 expression was detected using Western blot and immunohistochemical analyses. After administering ethylene glycol, oxalate concentration and prevalence of stone formation between the transgenic and control groups were measured using 24-h urine analysis and Von Kossa staining, respectively. Results Immunohistochemical and Western blot analyses indicated that stone formers had a significantly higher level of expression of SLC26A6 in the kidney compared with the control group. After lentivirus infection, the urinary oxalate concentration and rate of stone formation in lentivirus-Slc26a6-tranfected rats increased remarkably, while lentivirus-siRNA-Slc26a6-transfected rats showed few crystals. Conclusion The results showed that high expression levels of renal SLC26A6 may account for kidney stone formation. Downregulating the expression of SLC26A6 in the kidney may be a potential therapeutic target to prevent or treat urolithiasis.
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Affiliation(s)
- Hongyang Jiang
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gaurab Pokhrel
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yinwei Chen
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tao Wang
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chunping Yin
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jihong Liu
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shaogang Wang
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhuo Liu
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Whittamore JM, Hatch M. Oxalate transport by the mouse intestine in vitro is not affected by chronic challenges to systemic acid-base homeostasis. Urolithiasis 2018; 47:243-254. [PMID: 29947993 DOI: 10.1007/s00240-018-1067-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/10/2018] [Indexed: 12/15/2022]
Abstract
In rats, we recently showed how a chronic metabolic acidosis simultaneously reduced urinary oxalate excretion and promoted oxalate secretion by the distal colon leading to the proposition that acid-base disturbances may trigger changes to renal and intestinal oxalate handling. The present study sought to reproduce and extend these observations using the mouse model, where the availability of targeted gene knockouts (KOs) would offer future opportunities to reveal some of the underlying transporters and mechanisms involved. Mice were provided with a sustained load of acid (NH4Cl), base (NaHCO3) or the carbonic anhydrase inhibitor acetazolamide (ATZ) for 7 days after which time the impacts on urinary oxalate excretion and its transport by the intestine were evaluated. Mice consuming NH4Cl developed a metabolic acidosis but urinary oxalate was only reduced 46% and not statistically different from the control group, while provision of NaHCO3 provoked a significant 2.6-fold increase in oxalate excretion. For mice receiving ATZ, the rate of urinary oxalate excretion did not change significantly. Critically, none of these treatments altered the fluxes of oxalate (or chloride) across the distal ileum, cecum or distal colon. Hence, we were unable to produce the same effects of a metabolic acidosis in mice that we had previously found in rats, failing to find any evidence of the 'gut-kidney axis' influencing oxalate handling in response to various acid-base challenges. Despite the potential advantages offered by KO mice, this model species is not suitable for exploring how acid-base status regulates oxalate handling between the kidney and intestine.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, PO Box 100275, 1600 SW Archer Rd, Gainesville, FL, 32610, USA.
| | - Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, PO Box 100275, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
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Abstract
BACKGROUND Bariatric surgery is associated with hyperoxaluria hence predisposing to nephrolithiasis. The present study aimed to investigate the underlying mechanisms contributing to increased urinary oxalate in a mini-gastric bypass (MGB) surgery model in rats under different dietary conditions. The expression of intestinal oxalate transporters was also evaluated. METHODS Male rats underwent MGB (n = 21) or Sham procedure (n = 21) and after recovery were fed a standard or high-fat diet with or without oxalate for 8 weeks. Stool and urine were collected before surgery (baseline) and at the end of protocol (final), when intestinal fragments were harvested for expression of Slc26a3 and Slc26a6 oxalate transporters. RESULTS MGB groups fed with fat, irrespective of oxalate supplementation, presented steatorrhea. In MGB animals fed with fat and oxalate (Fat + Ox), final values of urinary oxalate and calcium oxalate supersaturation risk were markedly and significantly increased versus baseline or Sham animals under the same diet, as well as MGB groups under other diets. Slc26a3 was decreased in biliopancreatic limbs of MGB rats, probably reflecting a physiological adaptation to the restriction of food passage. Slc26a6 was not altered in any harvested intestinal fragment. CONCLUSIONS A high-fat and oxalate diet induced hyperoxaluria and elevation in calcium oxalate supersaturation risk in a MGB rat model. The presence of fat malabsorption and increased dietary oxalate absorption, but not modifications of Slc26a3 and Slc26a6 oxalate transporters, accounted for these findings, suggesting that bariatric patients may benefit from a low-fat and low-oxalate diet.
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Mukaibo T, Munemasa T, George AT, Tran DT, Gao X, Herche JL, Masaki C, Shull GE, Soleimani M, Melvin JE. The apical anion exchanger Slc26a6 promotes oxalate secretion by murine submandibular gland acinar cells. J Biol Chem 2018; 293:6259-6268. [PMID: 29530983 PMCID: PMC5925796 DOI: 10.1074/jbc.ra118.002378] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/08/2018] [Indexed: 12/15/2022] Open
Abstract
The solute carrier family 26 (SLC26) gene family encodes at least 10 different anion exchangers. SLC26 member 6 (SLC26A6 or CFEX/PAT-1) and the cystic fibrosis transmembrane conductance regulator (CFTR) co-localize to the apical membrane of pancreatic duct cells, where they act in concert to drive HCO3- and fluid secretion. In contrast, in the small intestine, SLC26A6 serves as the major pathway for oxalate secretion. However, little is known about the function of Slc26a6 in murine salivary glands. Here, RNA sequencing-based transcriptional profiling and Western blots revealed that Slc26a6 is highly expressed in mouse submandibular and sublingual salivary glands. Slc26a6 localized to the apical membrane of salivary gland acinar cells with no detectable immunostaining in the ducts. CHO-K1 cells transfected with mouse Slc26a6 exchanged Cl- for oxalate and HCO3-, whereas two other anion exchangers known to be expressed in salivary gland acinar cells, Slc4a4 and Slc4a9, mediated little, if any, Cl-/oxalate exchange. Of note, both Cl-/oxalate exchange and Cl-/HCO3- exchange were significantly reduced in acinar cells isolated from the submandibular glands of Slc26a6-/- mice. Oxalate secretion in submandibular saliva also decreased significantly in Slc26a6-/- mice, but HCO3- secretion was unaffected. Taken together, our findings indicate that Slc26a6 is located at the apical membrane of salivary gland acinar cells, where it mediates Cl-/oxalate exchange and plays a critical role in the secretion of oxalate into saliva.
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Affiliation(s)
- Taro Mukaibo
- From the Secretory Mechanisms and Dysfunctions Section and
- the Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Kitakyushu, Fukuoka 803-8580, Japan
| | - Takashi Munemasa
- From the Secretory Mechanisms and Dysfunctions Section and
- the Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Kitakyushu, Fukuoka 803-8580, Japan
| | - Alvin T George
- From the Secretory Mechanisms and Dysfunctions Section and
| | - Duy T Tran
- Biological Chemistry Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Xin Gao
- From the Secretory Mechanisms and Dysfunctions Section and
- the Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, Maryland 20742, and
| | - Jesse L Herche
- From the Secretory Mechanisms and Dysfunctions Section and
| | - Chihiro Masaki
- the Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Kitakyushu, Fukuoka 803-8580, Japan
| | - Gary E Shull
- Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267
| | | | - James E Melvin
- From the Secretory Mechanisms and Dysfunctions Section and
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47
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Amin R, Asplin J, Jung D, Bashir M, Alshaikh A, Ratakonda S, Sharma S, Jeon S, Granja I, Matern D, Hassan H. Reduced active transcellular intestinal oxalate secretion contributes to the pathogenesis of obesity-associated hyperoxaluria. Kidney Int 2018; 93:1098-1107. [PMID: 29395336 DOI: 10.1016/j.kint.2017.11.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 10/26/2017] [Accepted: 11/09/2017] [Indexed: 02/07/2023]
Abstract
Most kidney stones are composed of calcium oxalate, and minor changes in urine oxalate affect the stone risk. Obesity is a risk factor for kidney stones and a positive correlation of unknown etiology between increased body size, and elevated urinary oxalate excretion has been reported. Here, we used obese ob/ob (ob) mice to elucidate the pathogenesis of obesity-associated hyperoxaluria. These ob mice have significant hyperoxaluria (3.3-fold) compared with control mice, which is not due to overeating as shown by pair-feeding studies. Dietary oxalate removal greatly ameliorated this hyperoxaluria, confirming that it is largely enteric in origin. Transporter SLC26A6 (A6) plays an essential role in active transcellular intestinal oxalate secretion, and ob mice have significantly reduced jejunal A6 mRNA (- 80%) and total protein (- 62%) expression. While net oxalate secretion was observed in control jejunal tissues mounted in Ussing chambers, net absorption was seen in ob tissues, due to significantly reduced secretion. We hypothesized that the obesity-associated increase in intestinal and systemic inflammation, as reflected by elevated proinflammatory cytokines, suppresses A6-mediated intestinal oxalate secretion and contributes to obesity-associated hyperoxaluria. Indeed, proinflammatory cytokines (elevated in ob mice) significantly decreased intestinal oxalate transport in vitro by reducing A6 mRNA and total protein expression. Proinflammatory cytokines also significantly reduced active mouse jejunal oxalate secretion, converting oxalate transport from net secretion in vehicle-treated tissues to net absorption in proinflammatory cytokines-treated tissues. Thus, reduced active intestinal oxalate secretion, likely secondary to local and systemic inflammation, contributes to the pathogenesis of obesity-associated hyperoxaluria. Hence, proinflammatory cytokines represent potential therapeutic targets.
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Affiliation(s)
- Ruhul Amin
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - John Asplin
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois, USA
| | - Daniel Jung
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Mohamed Bashir
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Altayeb Alshaikh
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Sireesha Ratakonda
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Sapna Sharma
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Sohee Jeon
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Ignacio Granja
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois, USA
| | - Dietrich Matern
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Hatim Hassan
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA.
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48
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Abstract
Amelogenesis (tooth enamel formation) is a biomineralization process consisting primarily of two stages (secretory stage and maturation stage) with unique features. During the secretory stage, the inner epithelium of the enamel organ (i.e., the ameloblast cells) synthesizes and secretes enamel matrix proteins (EMPs) into the enamel space. The protein-rich enamel matrix forms a highly organized architecture in a pH-neutral microenvironment. As amelogenesis transitions to maturation stage, EMPs are degraded and internalized by ameloblasts through endosomal-lysosomal pathways. Enamel crystallite formation is initiated early in the secretory stage, however, during maturation stage the more rapid deposition of calcium and phosphate into the enamel space results in a rapid expansion of crystallite length and mineral volume. During maturation-stage amelogenesis, the pH value of enamel varies considerably from slightly above neutral to acidic. Extracellular acid-base balance during enamel maturation is tightly controlled by ameloblast-mediated regulatory networks, which include significant synthesis and movement of bicarbonate ions from both the enamel papillary layer cells and ameloblasts. In this review we summarize the carbonic anhydrases and the carbonate transporters/exchangers involved in pH regulation in maturation-stage amelogenesis. Proteins that have been shown to be instrumental in this process include CA2, CA6, CFTR, AE2, NBCe1, SLC26A1/SAT1, SLC26A3/DRA, SLC26A4/PDS, SLC26A6/PAT1, and SLC26A7/SUT2. In addition, we discuss the association of miRNA regulation with bicarbonate transport in tooth enamel formation.
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Affiliation(s)
- Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA, 90033, USA
- Department of Orthodontics, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA, 90033, USA.
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49
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Albert A, Tiwari V, Paul E, Ponnusamy S, Ganesan D, Prabhakaran R, Mariaraj Sivakumar S, Govindan Sadasivam S. Oral administration of oxalate-enriched spinach extract as an improved methodology for the induction of dietary hyperoxaluric nephrocalcinosis in experimental rats. Toxicol Mech Methods 2017; 28:195-204. [DOI: 10.1080/15376516.2017.1388459] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Abhishek Albert
- Department of Biochemistry, Centre for Excellence in Genomics Science, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - Vidhi Tiwari
- Department of Biochemistry, Centre for Excellence in Genomics Science, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - Eldho Paul
- Department of Biochemistry, Centre for Excellence in Genomics Science, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - Sasikumar Ponnusamy
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA
| | - Divya Ganesan
- Department of Biochemistry, Centre for Excellence in Genomics Science, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - Rajkumar Prabhakaran
- Department of Biochemistry, Centre for Excellence in Genomics Science, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - Selvi Mariaraj Sivakumar
- Department of Biochemistry, Centre for Excellence in Genomics Science, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - Selvam Govindan Sadasivam
- Department of Biochemistry, Centre for Excellence in Genomics Science, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
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50
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Whittamore JM, Hatch M. Loss of the anion exchanger DRA (Slc26a3), or PAT1 (Slc26a6), alters sulfate transport by the distal ileum and overall sulfate homeostasis. Am J Physiol Gastrointest Liver Physiol 2017; 313:G166-G179. [PMID: 28526688 PMCID: PMC5625136 DOI: 10.1152/ajpgi.00079.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 05/11/2017] [Accepted: 05/15/2017] [Indexed: 01/31/2023]
Abstract
The ileum is considered the primary site of inorganic sulfate ([Formula: see text]) absorption. In the present study, we explored the contributions of the apical chloride/bicarbonate (Cl-/[Formula: see text]) exchangers downregulated in adenoma (DRA; Slc26a3), and putative anion transporter 1 (PAT1; Slc26a6), to the underlying transport mechanism. Transepithelial 35[Formula: see text] and 36Cl- fluxes were determined across isolated, short-circuited segments of the distal ileum from wild-type (WT), DRA-knockout (KO), and PAT1-KO mice, together with measurements of urine and plasma sulfate. The WT distal ileum supported net sulfate absorption [197.37 ± 13.61 (SE) nmol·cm-2·h-1], but neither DRA nor PAT1 directly contributed to the unidirectional mucosal-to-serosal flux ([Formula: see text]), which was sensitive to serosal (but not mucosal) DIDS, dependent on Cl-, and regulated by cAMP. However, the absence of DRA significantly enhanced net sulfate absorption by one-third via a simultaneous rise in [Formula: see text] and a 30% reduction to the secretory serosal-to-mucosal flux ([Formula: see text]). We propose that DRA, together with PAT1, contributes to [Formula: see text] by mediating sulfate efflux across the apical membrane. Associated with increased ileal sulfate absorption in vitro, plasma sulfate was 61% greater, and urinary sulfate excretion (USO4) 2.2-fold higher, in DRA-KO mice compared with WT controls, whereas USO4 was increased 1.8-fold in PAT1-KO mice. These alterations to sulfate homeostasis could not be accounted for by any changes to renal sulfate handling suggesting that the source of this additional sulfate was intestinal. In summary, we characterized transepithelial sulfate fluxes across the mouse distal ileum demonstrating that DRA (and to a lesser extent, PAT1) secretes sulfate with significant implications for intestinal sulfate absorption and overall homeostasis.NEW & NOTEWORTHY Sulfate is an essential anion that is actively absorbed from the small intestine involving members of the Slc26 gene family. Here, we show that the main intestinal chloride transporter Slc26a3, known as downregulated in adenoma (DRA), also handles sulfate and contributes to its secretion into the lumen. In the absence of functional DRA (as in the disease congenital chloride diarrhea), net intestinal sulfate absorption was significantly enhanced resulting in substantial alterations to overall sulfate homeostasis.
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Affiliation(s)
- Jonathan M. Whittamore
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida
| | - Marguerite Hatch
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida
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