1
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Wiersma LE, Avramut MC, Koster AJ, van den Berg CW, Rabelink TJ. Ultrastructural characterization of maturing iPSC-derived nephron structures upon transplantation. Microsc Res Tech 2024; 87:495-505. [PMID: 37929605 DOI: 10.1002/jemt.24447] [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: 07/27/2023] [Revised: 09/29/2023] [Accepted: 10/14/2023] [Indexed: 11/07/2023]
Abstract
Pluripotent stem cell-derived kidney organoids hold great promise as a potential auxiliary transplant tissue for individuals with end-stage renal disease and as a platform for studying kidney diseases and drug discovery. To establish accurate models, it is crucial to thoroughly characterize the morphological features and maturation stages of the cellular components within these organoids. Nephrons, the functional units of the kidney, possess distinct morphological structures that directly correlate with their specific functions. High spatial resolution imaging emerges as a powerful technique for capturing ultrastructural details that may go unnoticed with other methods such as immunofluorescent imaging and scRNA sequencing. In our study, we have applied software capable of seamlessly stitching virtual slides generated from electron microscopy, resulting in high-definition overviews of tissue slides. With this technology, we can comprehensively characterize the development and maturation of kidney organoids when transplanted under the renal capsule of mice. These organoids exhibit advanced ultrastructural developments upon transplantation, including the formation of the filtration barrier in the renal corpuscle, the presence of microvilli in the proximal tubule, and various types of cell sub-segmentation in the connecting tubule similarly to those seen in the adult kidney. Such ultrastructural characterization provides invaluable insights into the structural development and functional morphology of nephron segments within kidney organoids and how to advance them by interventions such as a transplantation. Research Highlights High-resolution imaging is crucial to determine morphological maturation of hiPSC-derived kidney organoids. Upon transplantation, refined ultrastructural development of nephron segments was observed, such as the development of the glomerular filtration barrier.
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Affiliation(s)
- L E Wiersma
- Department of Internal Medicine - Nephrology, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory of Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - M C Avramut
- Department of Internal Medicine - Nephrology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Cell and Chemical Biology - Electron Microscopy Facility, Leiden University Medical Center, Leiden, The Netherlands
| | - A J Koster
- Department of Cell and Chemical Biology - Electron Microscopy Facility, Leiden University Medical Center, Leiden, The Netherlands
| | - C W van den Berg
- Department of Internal Medicine - Nephrology, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory of Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
- The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), Leiden University Medical Center, Leiden, The Netherlands
| | - T J Rabelink
- Department of Internal Medicine - Nephrology, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory of Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
- The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), Leiden University Medical Center, Leiden, The Netherlands
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2
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Baalmann F, Brendler J, Butthof A, Popkova Y, Engel KM, Schiller J, Winter K, Lede V, Ricken A, Schöneberg T, Schulz A. Reduced urine volume and changed renal sphingolipid metabolism in P2ry14-deficient mice. Front Cell Dev Biol 2023; 11:1128456. [PMID: 37250906 PMCID: PMC10213973 DOI: 10.3389/fcell.2023.1128456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 04/28/2023] [Indexed: 05/31/2023] Open
Abstract
The UDP-glucose receptor P2RY14, a rhodopsin-like G protein-coupled receptor (GPCR), was previously described as receptor expressed in A-intercalated cells of the mouse kidney. Additionally, we found P2RY14 is abundantly expressed in mouse renal collecting duct principal cells of the papilla and epithelial cells lining the renal papilla. To better understand its physiological function in kidney, we took advantage of a P2ry14 reporter and gene-deficient (KO) mouse strain. Morphometric studies showed that the receptor function contributes to kidney morphology. KO mice had a broader cortex relative to the total kidney area than wild-type (WT) mice. In contrast, the area of the outer stripe of the outer medulla was larger in WT compared to KO mice. Transcriptome comparison of the papilla region of WT and KO mice revealed differences in the gene expression of extracellular matrix proteins (e.g., decorin, fibulin-1, fibulin-7) and proteins involved in sphingolipid metabolism (e.g., small subunit b of the serine palmitoyltransferase) and other related GPCRs (e.g., GPR171). Using mass spectrometry, changes in the sphingolipid composition (e.g., chain length) were detected in the renal papilla of KO mice. At the functional level, we found that KO mice had a reduced urine volume but an unchanged glomerular filtration rate under normal chow and salt diets. Our study revealed P2ry14 as a functionally important GPCR in collecting duct principal cells and cells lining the renal papilla and the possible involvement of P2ry14 in nephroprotection by regulation of decorin.
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Affiliation(s)
- Fabian Baalmann
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Jana Brendler
- Institute of Anatomy, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Anne Butthof
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Yulia Popkova
- Institute of Medical Physics and Biophysics, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Kathrin M. Engel
- Institute of Medical Physics and Biophysics, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Jürgen Schiller
- Institute of Medical Physics and Biophysics, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Karsten Winter
- Institute of Anatomy, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Vera Lede
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Albert Ricken
- Institute of Anatomy, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Angela Schulz
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, Leipzig, Germany
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3
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Zhong QM, Wang JL. Seasonal flexibility of kidney structure and factors regulating water and salt in Eremias multiocellata. Comp Biochem Physiol A Mol Integr Physiol 2022; 274:111301. [DOI: 10.1016/j.cbpa.2022.111301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/21/2022] [Accepted: 08/21/2022] [Indexed: 12/05/2022]
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4
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Kumar P, Zadjali F, Yao Y, Johnson D, Siroky B, Astrinidis A, Vogel P, Gross KW, Bissler JJ. Tsc2 mutation induces renal tubular cell nonautonomous disease. Genes Dis 2022; 9:187-200. [PMID: 35005118 PMCID: PMC8720703 DOI: 10.1016/j.gendis.2021.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 01/22/2023] Open
Abstract
TSC renal cystic disease is poorly understood and has no approved treatment. In a new principal cell-targeted murine model of Tsc cystic disease, the renal cystic epithelium is mostly composed of type A intercalated cells with an intact Tsc2 gene confirmed by sequencing, although these cells exhibit a Tsc-mutant disease phenotype. We used a newly derived targeted murine model in lineage tracing and extracellular vesicle (EV) characterization experiments and a cell culture model in EV characterization and cellular induction experiments to understand TSC cystogenesis. Using lineage tracing experiments, we found principal cells undergo clonal expansion but contribute very few cells to the cyst. We determined that cystic kidneys contain more interstitial EVs than noncystic kidneys, excrete fewer EVs in urine, and contain EVs in cyst fluid. Moreover, the loss of Tsc2 gene in EV-producing cells greatly changes the effect of EVs on renal tubular epithelium, such that the epithelium develops increased secretory and proliferative pathway activity. We demonstate that the mTORC1 pathway activity is independent form the EV production, and that the EV effects for a single cell line can vary significantly. TSC cystogenesis involves significant contribution from genetically intact cells conscripted to the mutant phenotype by mutant cell derived EVs.
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Affiliation(s)
- Prashant Kumar
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38103, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA
| | - Fahad Zadjali
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38103, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Department of Clinical Biochemistry, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Ying Yao
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38103, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA
| | - Daniel Johnson
- Molecular Bioinformatics Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Brian Siroky
- Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA
| | - Aristotelis Astrinidis
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38103, USA
| | - Peter Vogel
- Department of Veterinary Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Kenneth W Gross
- Department of Molecular and Cellular Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - John J Bissler
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38103, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Pediatric Medicine Department, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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5
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Sarkany B, Kovacs G. Connecting tubules develop from the tip of the ureteric bud in the human kidney. Histochem Cell Biol 2021; 156:555-560. [PMID: 34554322 DOI: 10.1007/s00418-021-02033-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2021] [Indexed: 01/14/2023]
Abstract
The connecting tubule (CNT) is a unique segment of the nephron connecting the metanephric mesenchyme (MM)-derived distal convoluted tubule (DCT) and ureteric bud (UB)-derived collecting duct (CD). Views on the cellular origin of the CNT in the human kidney are controversial. It was suggested that in mice, the connecting segment arises from the distal compartment of the renal vesicle (RV). However, there are several differences in embryonic development between the mouse and human kidney. The aim of our study was to establish the possible origin of the CNT in the human kidney. We analysed the expression of markers defining distinct cells of the CNT CD in foetal and adult human kidneys by immunohistochemistry. Based on microscopic observation, we suggest that CNT differentiates from the outgrowth of cells of the UB tip, and therefore the CNT is an integral part of the CD system. In the adult kidney, the CNT and CD consist of functionally and morphologically similar cells expressing α- and β-intercalated cell (IC) and principal cell (PC) markers, indicating their common origin.
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Affiliation(s)
- Beatrix Sarkany
- Department of Urology, Medical School, University of Pecs, Pecs, 7621, Hungary
| | - Gyula Kovacs
- Department of Urology, Medical School, University of Pecs, Pecs, 7621, Hungary.
- Medical Faculty, Ruprecht-Karls-University, 69120, Heidelberg, Germany.
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6
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Kumar P, Zadjali F, Yao Y, Bissler JJ. Renal cystic disease in tuberous sclerosis complex. Exp Biol Med (Maywood) 2021; 246:2111-2117. [PMID: 34488473 DOI: 10.1177/15353702211038378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is associated with TSC1 or TSC2 gene mutations resulting in hyperactivation of the mTORC1 pathway. This mTORC1 activation is associated with abnormal tissue development and proliferation such that in the kidney there are both solid tumors and cystic lesions. This review summarizes recent advances in tuberous sclerosis complex nephrology and focuses on the genetics and cell biology of tuberous sclerosis complex renal disease, highlighting a role of extracellular vesicles and the innate immune system in disease pathogenesis.
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Affiliation(s)
- Prashant Kumar
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA
| | - Fahad Zadjali
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Department of Clinical Biochemistry, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, PC 123, Oman
| | - Ying Yao
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA
| | - John J Bissler
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105, USA.,Pediatric Medicine Department, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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7
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Wall SM, Verlander JW, Romero CA. The Renal Physiology of Pendrin-Positive Intercalated Cells. Physiol Rev 2020; 100:1119-1147. [PMID: 32347156 PMCID: PMC7474261 DOI: 10.1152/physrev.00011.2019] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 11/06/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022] Open
Abstract
Intercalated cells (ICs) are found in the connecting tubule and the collecting duct. Of the three IC subtypes identified, type B intercalated cells are one of the best characterized and known to mediate Cl- absorption and HCO3- secretion, largely through the anion exchanger pendrin. This exchanger is thought to act in tandem with the Na+-dependent Cl-/HCO3- exchanger, NDCBE, to mediate net NaCl absorption. Pendrin is stimulated by angiotensin II and aldosterone administration via the angiotensin type 1a and the mineralocorticoid receptors, respectively. It is also stimulated in models of metabolic alkalosis, such as with NaHCO3 administration. In some rodent models, pendrin-mediated HCO3- secretion modulates acid-base balance. However, of probably more physiological or clinical significance is the role of these pendrin-positive ICs in blood pressure regulation, which occurs, at least in part, through pendrin-mediated renal Cl- absorption, as well as their effect on the epithelial Na+ channel, ENaC. Aldosterone stimulates ENaC directly through principal cell mineralocorticoid hormone receptor (ligand) binding and also indirectly through its effect on pendrin expression and function. In so doing, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. In addition to its role in Na+ and Cl- balance, pendrin affects the balance of other ions, such as K+ and I-. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contribution of pendrin-positive ICs in the kidney to distal nephron function and blood pressure.
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Affiliation(s)
- Susan M Wall
- Departments of Medicine and Physiology, Emory University School of Medicine, Atlanta, Georgia; and Department of Medicine, University of Florida, Gainesville, Florida
| | - Jill W Verlander
- Departments of Medicine and Physiology, Emory University School of Medicine, Atlanta, Georgia; and Department of Medicine, University of Florida, Gainesville, Florida
| | - Cesar A Romero
- Departments of Medicine and Physiology, Emory University School of Medicine, Atlanta, Georgia; and Department of Medicine, University of Florida, Gainesville, Florida
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8
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Yosypiv IV. Prorenin receptor in kidney development. Pediatr Nephrol 2017; 32:383-392. [PMID: 27160552 DOI: 10.1007/s00467-016-3365-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 02/26/2016] [Accepted: 02/29/2016] [Indexed: 01/11/2023]
Abstract
Prorenin receptor (PRR), a receptor for renin and prorenin and an accessory subunit of the vacuolar proton pump H+-ATPase, is expressed in the developing kidney. Global loss of PRR is lethal in mice, and PRR mutations are associated with a high blood pressure, left ventricular hypertrophy and X-linked mental retardation in humans. With the advent of modern gene targeting techniques, including conditional knockout approaches, several recent studies have demonstrated critical roles for the PRR in several lineages of the developing kidney. PRR signaling has been shown to be essential for branching morphogenesis of the ureteric bud (UB), nephron progenitor survival and nephrogenesis. PRR regulates these developmental events through interactions with other transcription and growth factors. Several targeted PRR knockout animal models have structural defects mimicking congenital anomalies of the kidney and urinary tract observed in humans. The aim of this review, is to highlight new insights into the cellular and molecular mechanisms by which PRR may regulate UB branching, terminal differentiation and function of UB-derived collecting ducts, nephron progenitor maintenance, progression of nephrogenesis and normal structural kidney development and function.
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Affiliation(s)
- Ihor V Yosypiv
- Section of Pediatric Nephrology, Department of Pediatrics, Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center, 1430 Tulane Avenue, SL-37, New Orleans, LA, 70112, USA.
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9
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Song R, Janssen A, Li Y, El-Dahr S, Yosypiv IV. Prorenin receptor controls renal branching morphogenesis via Wnt/β-catenin signaling. Am J Physiol Renal Physiol 2016; 312:F407-F417. [PMID: 28031172 DOI: 10.1152/ajprenal.00563.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/20/2016] [Accepted: 12/23/2016] [Indexed: 11/22/2022] Open
Abstract
The prorenin receptor (PRR) is a receptor for renin and prorenin, and an accessory subunit of the vacuolar proton pump H+-ATPase. Renal branching morphogenesis, defined as growth and branching of the ureteric bud (UB), is essential for mammalian kidney development. Previously, we demonstrated that conditional ablation of the PRR in the UB in PRRUB-/- mice causes severe defects in UB branching, resulting in marked kidney hypoplasia at birth. Here, we investigated the UB transcriptome using whole genome-based analysis of gene expression in UB cells, FACS-isolated from PRRUB-/-, and control kidneys at birth (P0) to determine the primary role of the PRR in terminal differentiation and growth of UB-derived collecting ducts. Three genes with expression in UB cells that previously shown to regulate UB branching morphogenesis, including Wnt9b, β-catenin, and Fgfr2, were upregulated, whereas the expression of Wnt11, Bmp7, Etv4, and Gfrα1 was downregulated. We next demonstrated that infection of immortalized UB cells with shPRR in vitro or deletion of the UB PRR in double-transgenic PRRUB-/-/BatGal+ mice, a reporter strain for β-catenin transcriptional activity, in vivo increases β-catenin activity in the UB epithelia. In addition to UB morphogenetic genes, the functional groups of differentially expressed genes within the downregulated gene set included genes involved in molecular transport, metabolic disease, amino acid metabolism, and energy production. Together, these data demonstrate that UB PRR performs essential functions during UB branching and collecting duct morphogenesis via control of a hierarchy of genes that control UB branching and terminal differentiation of the collecting duct cells.
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Affiliation(s)
- Renfang Song
- Division of Pediatric Nephrology, Department of Pediatrics, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Lousiana
| | - Adam Janssen
- Division of Pediatric Nephrology, Department of Pediatrics, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Lousiana
| | - Yuwen Li
- Division of Pediatric Nephrology, Department of Pediatrics, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Lousiana
| | - Samir El-Dahr
- Division of Pediatric Nephrology, Department of Pediatrics, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Lousiana
| | - Ihor V Yosypiv
- Division of Pediatric Nephrology, Department of Pediatrics, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Lousiana
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10
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Abstract
The basic unit of kidney function is the nephron. In the mouse, around 14,000 nephrons form in a 10-day period extending into early neonatal life, while the human fetus forms the adult complement of nephrons in a 32-week period completed prior to birth. This review discusses our current understanding of mammalian nephrogenesis: the contributing cell types and the regulatory processes at play. A conceptual developmental framework has emerged for the mouse kidney. This framework is now guiding studies of human kidney development enabled in part by in vitro systems of pluripotent stem cell-seeded nephrogenesis. A near future goal will be to translate our developmental knowledge-base to the productive engineering of new kidney structures for regenerative medicine.
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Affiliation(s)
- Andrew P McMahon
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.
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11
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Schwartz GJ, Gao X, Tsuruoka S, Purkerson JM, Peng H, D'Agati V, Picard N, Eladari D, Al-Awqati Q. SDF1 induction by acidosis from principal cells regulates intercalated cell subtype distribution. J Clin Invest 2015; 125:4365-74. [PMID: 26517693 DOI: 10.1172/jci80225] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 09/11/2015] [Indexed: 12/13/2022] Open
Abstract
The nephron cortical collecting duct (CCD) is composed of principal cells, which mediate Na, K, and water transport, and intercalated cells (ICs), which are specialized for acid-base transport. There are two canonical IC forms: acid-secreting α-ICs and HCO3-secreting β-ICs. Chronic acidosis increases α-ICs at the expense of β-ICs, thereby increasing net acid secretion by the CCD. We found by growth factor quantitative PCR array that acidosis increases expression of mRNA encoding SDF1 (or CXCL12) in kidney cortex and isolated CCDs from mouse and rabbit kidney cortex. Exogenous SDF1 or pH 6.8 media increased H+ secretion and decreased HCO3 secretion in isolated perfused rabbit CCDs. Acid-dependent changes in H+ and HCO3 secretion were largely blunted by AMD3100, which selectively blocks the SDF1 receptor CXCR4. In mice, diet-induced chronic acidosis increased α-ICs and decreased β-ICs. Additionally, IC-specific Cxcr4 deletion prevented IC subtype alterations and magnified metabolic acidosis. SDF1 was transcriptionally regulated and a target of the hypoxia-sensing transcription factor HIF1α. IC-specific deletion of Hif1a produced no effect on mice fed an acid diet, as α-ICs increased and β-ICs decreased similarly to that observed in WT littermates. However, Hif1a deletion in all CCD cells prevented acidosis-induced IC subtype distribution, resulting in more severe acidosis. Cultured principal cells exhibited an HIF1α-dependent increase of Sdf1 transcription in response to media acidification. Thus, our results indicate that principal cells respond to acid by producing SDF1, which then acts on adjacent ICs.
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MESH Headings
- Animals
- Cells, Cultured
- Chemokine CXCL12/biosynthesis
- Chemokine CXCL12/genetics
- Hydrogen-Ion Concentration
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Ion Transport/physiology
- Kidney Glomerulus/cytology
- Kidney Glomerulus/metabolism
- Kidney Tubules, Collecting/cytology
- Kidney Tubules, Collecting/metabolism
- Mice
- Mice, Transgenic
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Rabbits
- Receptors, CXCR4/genetics
- Receptors, CXCR4/metabolism
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Abstract
The H(+) concentration in human blood is kept within very narrow limits, ~40 nmol/L, despite the fact that dietary metabolism generates acid and base loads that are added to the systemic circulation throughout the life of mammals. One of the primary functions of the kidney is to maintain the constancy of systemic acid-base chemistry. The kidney has evolved the capacity to regulate blood acidity by performing three key functions: (i) reabsorb HCO3(-) that is filtered through the glomeruli to prevent its excretion in the urine; (ii) generate a sufficient quantity of new HCO3(-) to compensate for the loss of HCO3(-) resulting from dietary metabolic H(+) loads and loss of HCO3(-) in the urea cycle; and (iii) excrete HCO3(-) (or metabolizable organic anions) following a systemic base load. The ability of the kidney to perform these functions requires that various cell types throughout the nephron respond to changes in acid-base chemistry by modulating specific ion transport and/or metabolic processes in a coordinated fashion such that the urine and renal vein chemistry is altered appropriately. The purpose of the article is to provide the interested reader with a broad review of a field that began historically ~60 years ago with whole animal studies, and has evolved to where we are currently addressing questions related to kidney acid-base regulation at the single protein structure/function level.
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Affiliation(s)
- Ira Kurtz
- Division of Nephrology, David Geffen School of Medicine, Los Angeles, CA; Brain Research Institute, UCLA, Los Angeles, CA
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13
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Furukawa F, Tseng YC, Liu ST, Chou YL, Lin CC, Sung PH, Uchida K, Lin LY, Hwang PP. Induction of Phosphoenolpyruvate Carboxykinase (PEPCK) during Acute Acidosis and Its Role in Acid Secretion by V-ATPase-Expressing Ionocytes. Int J Biol Sci 2015; 11:712-25. [PMID: 25999794 PMCID: PMC4440261 DOI: 10.7150/ijbs.11827] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 04/09/2015] [Indexed: 12/21/2022] Open
Abstract
Vacuolar-Type H+-ATPase (V-ATPase) takes the central role in pumping H+ through cell membranes of diverse organisms, which is essential for surviving acid-base fluctuating lifestyles or environments. In mammals, although glucose is believed to be an important energy source to drive V-ATPase, and phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme for gluconeogenesis, is known to be activated in response to acidosis, the link between acid secretion and PEPCK activation remains unclear. In the present study, we used zebrafish larva as an in vivo model to show the role of acid-inducible PEPCK activity in glucose production to support higher rate of H+ secretion via V-ATPase, by utilizing gene knockdown, glucose supplementation, and non-invasive scanning ion-selective electrode technique (SIET). Zebrafish larvae increased V-ATPase-mediated acid secretion and transiently expression of Pck1, a zebrafish homolog of PEPCK, in response to acid stress. When pck1 gene was knocked down by specific morpholino, the H+ secretion via V-ATPase decreased, but this effect was rescued by supplementation of glucose into the yolk. By assessing changes in amino acid content and gene expression of respective enzymes, glutamine and glutamate appeared to be the major source for replenishment of Krebs cycle intermediates, which are subtracted by Pck1 activity. Unexpectedly, pck1 knockdown did not affect glutamine/glutamate catalysis, which implies that Pck1 does not necessarily drive this process. The present study provides the first in vivo evidence that acid-induced PEPCK provides glucose for acid-base homeostasis at an individual level, which is supported by rapid pumping of H+ via V-ATPase at the cellular level.
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Affiliation(s)
- Fumiya Furukawa
- 1. Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan ; 2. Department of Marine Biology and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Yung-Che Tseng
- 3. Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Sian-Tai Liu
- 3. Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Yi-Ling Chou
- 1. Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan
| | - Ching-Chun Lin
- 1. Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan
| | - Po-Hsuan Sung
- 4. Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Katsuhisa Uchida
- 2. Department of Marine Biology and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Li-Yih Lin
- 3. Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Pung-Pung Hwang
- 1. Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan
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14
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Azroyan A, Cortez-Retamozo V, Bouley R, Liberman R, Ruan YC, Kiselev E, Jacobson KA, Pittet MJ, Brown D, Breton S. Renal intercalated cells sense and mediate inflammation via the P2Y14 receptor. PLoS One 2015; 10:e0121419. [PMID: 25799465 PMCID: PMC4370445 DOI: 10.1371/journal.pone.0121419] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/01/2015] [Indexed: 12/31/2022] Open
Abstract
Uncontrolled inflammation is one of the leading causes of kidney failure. Pro-inflammatory responses can occur in the absence of infection, a process called sterile inflammation. Here we show that the purinergic receptor P2Y14 (GPR105) is specifically and highly expressed in collecting duct intercalated cells (ICs) and mediates sterile inflammation in the kidney. P2Y14 is activated by UDP-glucose, a damage-associated molecular pattern molecule (DAMP) released by injured cells. We found that UDP-glucose increases pro-inflammatory chemokine expression in ICs as well as MDCK-C11 cells, and UDP-glucose activates the MEK1/2-ERK1/2 pathway in MDCK-C11 cells. These effects were prevented following inhibition of P2Y14 with the small molecule PPTN. Tail vein injection of mice with UDP-glucose induced the recruitment of neutrophils to the renal medulla. This study identifies ICs as novel sensors, mediators and effectors of inflammation in the kidney via P2Y14.
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Affiliation(s)
- Anie Azroyan
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Virna Cortez-Retamozo
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Richard Bouley
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Rachel Liberman
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ye Chun Ruan
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Evgeny Kiselev
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kenneth A. Jacobson
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mikael J. Pittet
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Dennis Brown
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sylvie Breton
- Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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15
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Roy A, Al-bataineh MM, Pastor-Soler NM. Collecting duct intercalated cell function and regulation. Clin J Am Soc Nephrol 2015; 10:305-24. [PMID: 25632105 DOI: 10.2215/cjn.08880914] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Intercalated cells are kidney tubule epithelial cells with important roles in the regulation of acid-base homeostasis. However, in recent years the understanding of the function of the intercalated cell has become greatly enhanced and has shaped a new model for how the distal segments of the kidney tubule integrate salt and water reabsorption, potassium homeostasis, and acid-base status. These cells appear in the late distal convoluted tubule or in the connecting segment, depending on the species. They are most abundant in the collecting duct, where they can be detected all the way from the cortex to the initial part of the inner medulla. Intercalated cells are interspersed among the more numerous segment-specific principal cells. There are three types of intercalated cells, each having distinct structures and expressing different ensembles of transport proteins that translate into very different functions in the processing of the urine. This review includes recent findings on how intercalated cells regulate their intracellular milieu and contribute to acid-base regulation and sodium, chloride, and potassium homeostasis, thus highlighting their potential role as targets for the treatment of hypertension. Their novel regulation by paracrine signals in the collecting duct is also discussed. Finally, this article addresses their role as part of the innate immune system of the kidney tubule.
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Affiliation(s)
- Ankita Roy
- Renal-Electrolyte Division, Department of Medicine; and
| | | | - Núria M Pastor-Soler
- Renal-Electrolyte Division, Department of Medicine; and Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania A.R. and M.M.A. contributed equally to this work.
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16
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Renal acid-base regulation: new insights from animal models. Pflugers Arch 2014; 467:1623-41. [PMID: 25515081 DOI: 10.1007/s00424-014-1669-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/16/2022]
Abstract
Because majority of biological processes are dependent on pH, maintaining systemic acid-base balance is critical. The kidney contributes to systemic acid-base regulation, by reabsorbing HCO3 (-) (both filtered by glomeruli and generated within a nephron) and acidifying urine. Abnormalities in those processes will eventually lead to a disruption in systemic acid-base balance and provoke metabolic acid-base disorders. Research over the past 30 years advanced our understanding on cellular and molecular mechanisms responsible for those processes. In particular, a variety of transgenic animal models, where target genes are deleted either globally or conditionally, provided significant insights into how specific transporters are contributing to the renal acid-base regulation. Here, we broadly overview the mechanisms of renal ion transport participating to acid-base regulation, with emphasis on data obtained from transgenic mice models.
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17
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Guo Q, Wang Y, Tripathi P, Manda KR, Mukherjee M, Chaklader M, Austin PF, Surendran K, Chen F. Adam10 mediates the choice between principal cells and intercalated cells in the kidney. J Am Soc Nephrol 2014; 26:149-59. [PMID: 24904084 DOI: 10.1681/asn.2013070764] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A disintegrin and metalloproteinase domain 10 (Adam10), a member of the ADAM family of cell membrane-anchored proteins, has been linked to the regulation of the Notch, EGF, E-cadherin, and other signaling pathways. However, it is unclear what role Adam10 has in the kidney in vivo. In this study, we showed that Adam10 deficiency in ureteric bud (UB) derivatives leads to a decrease in urinary concentrating ability, polyuria, and hydronephrosis in mice. Furthermore, Adam10 deficiency led to a reduction in the percentage of aquaporin 2 (Aqp2)(+) principal cells (PCs) in the collecting ducts that was accompanied by a proportional increase in the percentage of intercalated cells (ICs). This increase was more prominent in type A ICs than in type B ICs. Foxi1, a transcription factor important for the differentiation of ICs, was upregulated in the Adam10 mutants. The observed reduction of Notch activity in Adam10 mutant collecting duct epithelium and the similar reduction of PC/IC ratios in the collecting ducts in mice deficient for mindbomb E3 ubiquitin protein ligase 1, a key regulator of the Notch and Wnt/receptor-like tyrosine kinase signaling pathways, suggest that Adam10 regulates cell fate determination through the activation of Notch signaling, probably through the regulation of Foxi1 expression. However, phenotypic differences between the Adam10 mutants, the Mib1 mutants, and the Foxi1 mutants suggest that the functions of Adam10 in determining the fate of collecting duct cells are more complex than those of a simple upstream factor in a linear pathway involving Notch and Foxi1.
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Affiliation(s)
- Qiusha Guo
- Department of Medicine, Department of Cell Biology and Physiology, and Division of Pediatric Urology, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Yinqiu Wang
- Department of Medicine, Department of Cell Biology and Physiology, and
| | - Piyush Tripathi
- Department of Medicine, Department of Cell Biology and Physiology, and
| | - Kalyan R Manda
- Department of Medicine, Department of Cell Biology and Physiology, and
| | - Malini Mukherjee
- Sanford Children's Health Research Center, Sanford Research/USD, Sioux Falls, South Dakota; and
| | - Malay Chaklader
- Sanford Children's Health Research Center, Sanford Research/USD, Sioux Falls, South Dakota; and
| | - Paul F Austin
- Division of Pediatric Urology, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Kameswaran Surendran
- Sanford Children's Health Research Center, Sanford Research/USD, Sioux Falls, South Dakota; and Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota
| | - Feng Chen
- Department of Medicine, Department of Cell Biology and Physiology, and
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18
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Miró-Julià C, Escoda-Ferran C, Carrasco E, Moeller JB, Vadekaer DF, Gao X, Paragas N, Oliver J, Holmskov U, Al-Awqati Q, Lozano F. Expression of the innate defense receptor S5D-SRCRB in the urogenital tract. ACTA ACUST UNITED AC 2014; 83:273-85. [DOI: 10.1111/tan.12330] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/28/2014] [Accepted: 02/11/2014] [Indexed: 12/19/2022]
Affiliation(s)
- C. Miró-Julià
- Grup d'Immunoreceptors, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Centre Esther Koplowitz; Barcelona Spain
| | - C. Escoda-Ferran
- Grup d'Immunoreceptors, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Centre Esther Koplowitz; Barcelona Spain
| | - E. Carrasco
- Grup d'Immunoreceptors, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Centre Esther Koplowitz; Barcelona Spain
| | - J. B. Moeller
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - D. F. Vadekaer
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - X. Gao
- Department of Medicine, College of Physicians and Surgeons; Columbia University; New York NY USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons; Columbia University; New York NY USA
| | - N. Paragas
- Department of Medicine, College of Physicians and Surgeons; Columbia University; New York NY USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons; Columbia University; New York NY USA
| | - J. Oliver
- Department of Medicine, College of Physicians and Surgeons; Columbia University; New York NY USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons; Columbia University; New York NY USA
| | - U. Holmskov
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - Q. Al-Awqati
- Department of Medicine, College of Physicians and Surgeons; Columbia University; New York NY USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons; Columbia University; New York NY USA
| | - F. Lozano
- Grup d'Immunoreceptors, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Centre Esther Koplowitz; Barcelona Spain
- Servei d'Immunologia, Centre de Diagnòstic Biomèdic; Hospital Clínic de Barcelona; Barcelona Spain
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina; Universitat de Barcelona; Barcelona Spain
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19
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Roldán ML, Marini PE. First evidence of the interaction between deleted in malignant brain tumor 1 and galectin-3 in the mammalian oviduct. Histochem Cell Biol 2013; 141:181-90. [PMID: 24065275 DOI: 10.1007/s00418-013-1145-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2013] [Indexed: 12/26/2022]
Abstract
The oviduct supports the transport and final maturation of gametes, and harbors fertilization and early embryo development. The oviductal epithelium is responsible for providing the correct environment for these processes. Deleted in malignant brain tumor 1 (DMBT1) is expressed by multiple organisms and several cell types, and the interaction of the rabbit ortholog of DMBT1 with galectin-3 (gal-3) modulates the polarity of epithelial cells. This interaction has not yet been shown in locations other than rabbit kidney and human-cultured endothelial cells. DMBT1 and gal-3 also protect epithelial layers from pathogens and trauma, and are innate immunity components. DMBT1 has been detected in the porcine oviduct, and gal-3 has been reported in the Fallopian tube and in the cow oviduct. Interaction between both proteins would show a probable physiological function in the female reproductive tract. This work describes the presence and co-localization of DMBT1 and gal-3 mainly in the apical region of the epithelial cells of the Fallopian tube and the porcine oviduct, and co-immunoprecipitation in membrane-enriched epithelial cell extracts from the porcine oviduct. The findings strongly support a functional interaction in the mammalian oviduct, suggestive of a role on epithelial protection and homeostasis, which might be related to epithelium-gamete interaction.
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Affiliation(s)
- M L Roldán
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Rosario, Argentina
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20
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Abstract
Antibacterial peptides and proteins maintain the sterility of the human urinary tract. A broad-spectrum antimicrobial protein, ribonuclease 7 (RNase 7), previously discovered to play a role in controlling the growth of bacteria on human skin, has now been shown to have an important antibacterial function in the human urinary tract.
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21
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Chang WJ, Wang YF, Hu HJ, Wang JH, Lee TH, Hwang PP. Compensatory regulation of Na+ absorption by Na+/H+ exchanger and Na+-Cl- cotransporter in zebrafish (Danio rerio). Front Zool 2013; 10:46. [PMID: 23924428 PMCID: PMC3750650 DOI: 10.1186/1742-9994-10-46] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 08/02/2013] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION In mammals, internal Na+ homeostasis is maintained through Na+ reabsorption via a variety of Na+ transport proteins with mutually compensating functions, which are expressed in different segments of the nephrons. In zebrafish, Na+ homeostasis is achieved mainly through the skin/gill ionocytes, namely Na+/H+ exchanger (NHE3b)-expressing H+-ATPase rich (HR) cells and Na+-Cl- cotransporter (NCC)-expressing NCC cells, which are functionally homologous to mammalian proximal and distal convoluted tubular cells, respectively. The present study aimed to investigate whether or not the functions of HR and NCC ionocytes are differentially regulated to compensate for disruptions of internal Na+ homeostasis and if the cell differentiation of the ionocytes is involved in this regulation pathway. RESULTS Translational knockdown of ncc caused an increase in HR cell number and a resulting augmentation of Na+ uptake in zebrafish larvae, while NHE3b loss-of-function caused an increase in NCC cell number with a concomitant recovery of Na+ absorption. Environmental acid stress suppressed nhe3b expression in HR cells and decreased Na+ content, which was followed by up-regulation of NCC cells accompanied by recovery of Na+ content. Moreover, knockdown of ncc resulted in a significant decrease of Na+ content in acid-acclimated zebrafish. CONCLUSIONS These results provide evidence that HR and NCC cells exhibit functional redundancy in Na+ absorption, similar to the regulatory mechanisms in mammalian kidney, and suggest this functional redundancy is a critical strategy used by zebrafish to survive in a harsh environment that disturbs body fluid Na+ homeostasis.
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Affiliation(s)
- Wei-Jen Chang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
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22
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Alzamora R, Al-Bataineh MM, Liu W, Gong F, Li H, Thali RF, Joho-Auchli Y, Brunisholz RA, Satlin LM, Neumann D, Hallows KR, Pastor-Soler NM. AMP-activated protein kinase regulates the vacuolar H+-ATPase via direct phosphorylation of the A subunit (ATP6V1A) in the kidney. Am J Physiol Renal Physiol 2013; 305:F943-56. [PMID: 23863464 DOI: 10.1152/ajprenal.00303.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The vacuolar H(+)-ATPase (V-ATPase) in intercalated cells contributes to luminal acidification in the kidney collecting duct and nonvolatile acid excretion. We previously showed that the A subunit in the cytoplasmic V1 sector of the V-ATPase (ATP6V1A) is phosphorylated by the metabolic sensor AMP-activated protein kinase (AMPK) in vitro and in kidney cells. Here, we demonstrate that treatment of rabbit isolated, perfused collecting ducts with the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) inhibited V-ATPase-dependent H(+) secretion from intercalated cells after an acid load. We have identified by mass spectrometry that Ser-384 is a major AMPK phosphorylation site in the V-ATPase A subunit, a result confirmed by comparing AMPK-dependent phosphate labeling of wild-type A-subunit (WT-A) with that of a Ser-384-to-Ala A subunit mutant (S384A-A) in vitro and in intact HEK-293 cells. Compared with WT-A-expressing HEK-293 cells, S384A-A-expressing cells exhibited greater steady-state acidification of HCO3(-)-containing media. Moreover, AICAR treatment of clone C rabbit intercalated cells expressing the WT-A subunit reduced V-ATPase-dependent extracellular acidification, an effect that was blocked in cells expressing the phosphorylation-deficient S384A-A mutant. Finally, expression of the S384A-A mutant prevented cytoplasmic redistribution of the V-ATPase by AICAR in clone C cells. In summary, direct phosphorylation of the A subunit at Ser-384 by AMPK represents a novel regulatory mechanism of the V-ATPase in kidney intercalated cells. Regulation of the V-ATPase by AMPK may couple V-ATPase activity to cellular metabolic status with potential relevance to ischemic injury in the kidney and other tissues.
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Affiliation(s)
- Rodrigo Alzamora
- Renal-Electrolyte Div., Dept. of Medicine, S976.1 Scaife Hall, 3550 Terrace St., Pittsburgh, PA 15261.
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23
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Deletion of the prorenin receptor from the ureteric bud causes renal hypodysplasia. PLoS One 2013; 8:e63835. [PMID: 23704941 PMCID: PMC3660567 DOI: 10.1371/journal.pone.0063835] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/07/2013] [Indexed: 01/04/2023] Open
Abstract
The role of the prorenin receptor (PRR) in the regulation of ureteric bud (UB) branching morphogenesis is unknown. Here, we investigated whether PRR acts specifically in the UB to regulate UB branching, kidney development and function. We demonstrate that embryonic (E) day E13.5 mouse metanephroi, isolated intact E11.5 UBs and cultured UB cells express PRR mRNA. To study its role in UB development, we conditionally ablated PRR in the developing UB (PRRUB−/−) using Hoxb7Cre mice. On E12.5, PRRUB−/− mice had decreased UB branching and increased UB cell apoptosis. These defects were associated with decreased expression of Ret, Wnt11, Etv4/Etv5, and reduced phosphorylation of Erk1/2 in the UB. On E18.5, mutants had marked kidney hypoplasia, widespread apoptosis of medullary collecting duct cells and decreased expression of Foxi1, AE1 and H+-ATPase α4 mRNA. Ultimately, they developed occasional small cysts in medullary collecting ducts and had decreased nephron number. To test the functional consequences of these alterations, we determined the ability of PRRUB−/− mice to acidify and concentrate the urine on postnatal (P) day P30. PRRUB−/− mice were polyuric, had lower urine osmolality and a higher urine pH following 48 hours of acidic loading with NH4Cl. Taken together, these data show that PRR present in the UB epithelia performs essential functions during UB branching morphogenesis and collecting duct development via control of Ret/Wnt11 pathway gene expression, UB cell survival, activation of Erk1/2, terminal differentiation and function of collecting duct cells needed for maintaining adequate water and acid-base homeostasis. We propose that mutations in PRR could possibly cause renal hypodysplasia and renal tubular acidosis in humans.
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24
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Hwang PP, Chou MY. Zebrafish as an animal model to study ion homeostasis. Pflugers Arch 2013; 465:1233-47. [PMID: 23568368 PMCID: PMC3745619 DOI: 10.1007/s00424-013-1269-1] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/11/2013] [Accepted: 03/12/2013] [Indexed: 01/27/2023]
Abstract
Zebrafish (Danio rerio) possesses several advantages as an experimental organism, including the applicability of molecular tools, ease of in vivo cellular observation and functional analysis, and rapid embryonic development, making it an emerging model for the study of integrative and regulatory physiology and, in particular, the epithelial transport associated with body fluid ionic homeostasis. Zebrafish inhabits a hypotonic freshwater environment, and as such, the gills (or the skin, during embryonic stages) assume the role of the kidney in body fluid ionic homeostasis. Four types of ionocyte expressing distinct sets of transporters have been identified in these organs: H+-ATPase-rich, Na+-K+-ATPase-rich, Na+-Cl− cotransporter-expressing and K+-secreting cells; these ionocytes perform transepithelial H+ secretion/Na+ uptake/NH4+ excretion, Ca2+ uptake, Na+/Cl− uptake, and K+ secretion, respectively. Zebrafish ionocytes are analogous to various renal tubular cells, in terms of ion transporter expression and function. During embryonic development, ionocyte progenitors develop from epidermal stem cells and then differentiate into different types of ionocyte through a positive regulatory loop of Foxi3a/-3b and other transcription factors. Several hormones, including cortisol, vitamin D, stanniocalcin-1, calcitonin, and isotocin, were found to participate in the control pathways of ionic homeostasis by precisely studying the target ion transport pathways, ion transporters, or ionocytes of the hormonal actions. In conclusion, the zebrafish model not only enhances our understanding of body fluid ion homeostasis and hormonal control in fish but also informs studies on mammals and other animal species, thereby providing new insights into related fields.
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Affiliation(s)
- Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
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25
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Paragas N, Qiu A, Hollmen M, Nickolas TL, Devarajan P, Barasch J. NGAL-Siderocalin in kidney disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1451-8. [PMID: 22728330 DOI: 10.1016/j.bbamcr.2012.06.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/06/2012] [Accepted: 06/13/2012] [Indexed: 12/11/2022]
Abstract
Kidney damage induces the expression of a myriad of proteins in the serum and in the urine. The function of these proteins in the sequence of damage and repair is now being studied in genetic models and by novel imaging techniques. One of the most intensely expressed proteins is lipocalin2, also called NGAL or Siderocalin. While this protein has been best studied by clinical scientists, only a few labs study its underlying metabolism and function in tissue damage. Structure-function studies, imaging studies and clinical studies have revealed that NGAL-Siderocalin is an endogenous antimicrobial with iron scavenging activity. This review discusses the "iron problem" of kidney damage, the tight linkage between kidney damage and NGAL-Siderocalin expression and the potential roles that NGAL-Siderocalin may serve in the defense of the urogenital system. This article is part of a Special Issue entitled: Cell Biology of Metals.
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Affiliation(s)
- Neal Paragas
- College of Physicians & Surgeons of Columbia University, New York, NY, USA
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