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Vanichapol T, Gonzalez A, Delgado R, Brewer M, Clouthier KA, Menshikh A, Snyder WE, Rahman T, Sander V, Yang H, Davidson A, de Caestecker M. Partial repair causes permanent defects in papillary structure and function after reversal of urinary obstruction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.11.612436. [PMID: 39314319 PMCID: PMC11419032 DOI: 10.1101/2024.09.11.612436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Urinary obstruction causes injury to the renal papilla and leads to defects in the ability to concentrate urine which predisposes to progressive kidney injury. However, the regenerative capacity of the papilla after reversal of obstruction is poorly understood. To address this, we developed a mouse model of reversible urinary obstruction which is characterized by extensive papillary injury, followed by a robust regeneration response and complete histological recovery over a 3- month period. However, these mice have a pronounced defect in urinary concentrating capacity. We now show that this is due to permanent changes in the composition, organization, and transcriptional signatures of epithelial, endothelial, and interstitial cell lineages in the papilla. There are persistent inflammatory responses that are also seen in patients with renal stone disease but are associated with cell-specific adaptive responses to the increasingly hypoxic environment of the papilla after reversal of obstruction. Taken together, our analysis of a new model of reversible urinary obstruction reveals that partial repair leads to permanent changes in the structure and function of all of the major cellular compartments in the papilla that include both shared and distinct responses to different types of renal papillary injury in humans and mice. Summary Partial repair after reversal of urinary obstruction leads to permanent changes in structure and function of all major cellular compartments in the renal papilla.
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2
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Kuang SY. A better explanation of countercurrent multiplication in the formation of the corticopapillary osmotic gradient in the outer medulla. ADVANCES IN PHYSIOLOGY EDUCATION 2023; 47:665-671. [PMID: 37439318 DOI: 10.1152/advan.00227.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 06/15/2023] [Accepted: 07/10/2023] [Indexed: 07/14/2023]
Abstract
Countercurrent multiplication (CCM) is widely accepted as the mechanism for the generation of the corticopapillary osmotic gradient in the outer medulla of mammalian kidneys. However, several issues in the literature cause the current explanations of CCM to be inefficient and incomplete. As a result, it is challenging to clearly explain CCM in physiology education. The goal of this article is to share a modified version of CCM with more understandable explanation in the hopes of motivating peer discussion, further improvement, and future research. To reach this goal, the logical processes leading to CCM are first analyzed, which results in a set of formulas that serve as the principles governing CCM. Next, the cessation of CCM is addressed to provide a complete picture of the modified version of CCM. Throughout these two steps, the issues mentioned above are identified and addressed so that how the modified version of CCM eliminates these issues becomes clear. The formulas mentioned above are provided in the Tables S1, S2, and S3 (all Supplemental material is available in the Supplemental Excel File at https://doi.org/10.6084/m9.figshare.23515614) to explain how the interstitial and intrathick ascending limb osmotic concentration (OC) values used in the figures in this article are simulated and how alternative OC values can be generated from Tables S1 and S2 to illustrate CCM.NEW & NOTEWORTHY Countercurrent multiplication is widely accepted as the mechanism for the generation of the corticopapillary osmotic gradient in the outer medulla of mammalian kidneys, but the current explanations of it in textbooks and the literature are inefficient and incomplete, leading to confusion for students. This article shares a modified version of countercurrent multiplication with more understandable explanation as a way of motivating peer discussion, further improvement, and future research.
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Affiliation(s)
- Serena Y Kuang
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, Michigan, United States
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3
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Zhou T, Zhang S, Du C, Wang K, Gu X, Sun S, Zhang X, Niu Y, Wang C, Liu M, Dong N, Wu Q. Renal Corin Is Essential for Normal Blood Pressure and Sodium Homeostasis. Int J Mol Sci 2022; 23:ijms231911251. [PMID: 36232551 PMCID: PMC9570390 DOI: 10.3390/ijms231911251] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022] Open
Abstract
Atrial natriuretic peptide (ANP)-mediated natriuresis is known as a cardiac endocrine function in sodium and body fluid homeostasis. Corin is a protease essential for ANP activation. Here, we studied the role of renal corin in regulating salt excretion and blood pressure. We created corin conditional knockout (cKO), in which the Corin gene was selectively disrupted in the kidney (kcKO) or heart (hcKO). We examined the blood pressure, urinary Na+ and Cl− excretion, and cardiac hypertrophy in wild-type, corin global KO, kcKO, and hcKO mice fed normal- and high-salt diets. We found that on a normal-salt diet (0.3% NaCl), corin kcKO and hcKO mice had increased blood pressure, indicating that both renal and cardiac corin is necessary for normal blood pressure in mice. On a high-salt diet (4% NaCl), reduced urinary Na+ and Cl− excretion, increased body weight, salt-exacerbated hypertension, and cardiac hypertrophy were observed in corin kcKO mice. In contrast, impaired urinary Na+ and Cl− excretion and salt-exacerbated hypertension were not observed in corin hcKO mice. These results indicated that renal corin function is important in enhancing natriuresis upon high salt intakes and that this function cannot be compensated by the cardiac corin function in mice.
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Affiliation(s)
- Tiantian Zhou
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
| | - Shengnan Zhang
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, Soochow University, Suzhou 215006, China
| | - Chunyu Du
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, Soochow University, Suzhou 215006, China
| | - Kun Wang
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
| | - Xiabing Gu
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, Soochow University, Suzhou 215006, China
| | - Shijin Sun
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, Soochow University, Suzhou 215006, China
| | - Xianrui Zhang
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, Soochow University, Suzhou 215006, China
| | - Yayan Niu
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, Soochow University, Suzhou 215006, China
| | - Can Wang
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
| | - Meng Liu
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
| | - Ningzheng Dong
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, Soochow University, Suzhou 215006, China
- Correspondence: (N.D.); (Q.W.)
| | - Qingyu Wu
- Hematology Center, Cyrus Tang Medical Institute, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Suzhou Medical College, Soochow University, Suzhou 215123, China
- Correspondence: (N.D.); (Q.W.)
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4
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Lopez-Tello J, Jimenez-Martinez MA, Salazar-Petres E, Patel R, George AL, Kay RG, Sferruzzi-Perri AN. Identification of Structural and Molecular Signatures Mediating Adaptive Changes in the Mouse Kidney in Response to Pregnancy. Int J Mol Sci 2022; 23:6287. [PMID: 35682969 PMCID: PMC9181623 DOI: 10.3390/ijms23116287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/26/2022] [Accepted: 06/02/2022] [Indexed: 02/04/2023] Open
Abstract
Pregnancy is characterized by adaptations in the function of several maternal body systems that ensure the development of the fetus whilst maintaining health of the mother. The renal system is responsible for water and electrolyte balance, as well as waste removal. Thus, it is imperative that structural and functional changes occur in the kidney during pregnancy. However, our knowledge of the precise morphological and molecular mechanisms occurring in the kidney during pregnancy is still very limited. Here, we investigated the changes occurring in the mouse kidney during pregnancy by performing an integrated analysis involving histology, gene and protein expression assays, mass spectrometry profiling and bioinformatics. Data from non-pregnant and pregnant mice were used to identify critical signalling pathways mediating changes in the maternal kidneys. We observed an expansion of renal medulla due to proliferation and infiltration of interstitial cellular constituents, as well as alterations in the activity of key cellular signalling pathways (e.g., AKT, AMPK and MAPKs) and genes involved in cell growth/metabolism (e.g., Cdc6, Foxm1 and Rb1) in the kidneys during pregnancy. We also generated plasma and urine proteomic profiles, identifying unique proteins in pregnancy. These proteins could be used to monitor and study potential mechanisms of renal adaptations during pregnancy and disease.
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Affiliation(s)
- Jorge Lopez-Tello
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | | | - Esteban Salazar-Petres
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Ritik Patel
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Amy L George
- Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Richard G Kay
- Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Amanda N Sferruzzi-Perri
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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5
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Hansen-Estruch C, Cooper DK, Judd E. Physiological aspects of pig kidney xenotransplantation and implications for management following transplant. Xenotransplantation 2022; 29:e12743. [PMID: 35297098 PMCID: PMC9232961 DOI: 10.1111/xen.12743] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 02/19/2022] [Accepted: 03/03/2022] [Indexed: 12/16/2022]
Abstract
Successful organ transplantation between species is now possible, using genetic modifications. This article aims to provide a comprehensive overview of the differences and similarities in kidney function between humans, primates, and pigs, in preparation for pig-allograft to human xenotransplantation. The kidney, as the principal defender of body homeostasis, acts as a sensor, effector, and regulator of physiologic feedback systems. Considerations are made for anticipated effects on each system when a pig kidney is placed into a human recipient. Discussion topics include anatomy, global kidney function, sodium and water handling, kidney hormone production and response to circulating hormones, acid-base balance, and calcium and phosphorus handling. Based on available data, pig kidneys are anticipated to be compatible with human physiology, despite a few barriers.
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Affiliation(s)
- Christophe Hansen-Estruch
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David K.C. Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Eric Judd
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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6
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Abstract
An exploration of the normal limits of physiologic responses and how these responses are lost when the kidney is injured rarely occurs in clinical practice. However, the differences between "resting" and "stressed" responses identify an adaptive reactiveness that is diminished before baseline function is impaired. This functional reserve is important in the evaluation of prognosis and progression of kidney disease. Here, we discuss stress tests that examine protein-induced hyperfiltration, proximal tubular secretion, urea-selective concentration defects, and acid retention. We discuss diseases in which these tests have been used to diagnose subclinical injury. The study and follow-up of abnormal functional reserve may add considerable understanding to the natural history of CKD.
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Affiliation(s)
- Armando Armenta
- Department of Nephrology, National Institute of Cardiology “Ignacio Chavez,” Mexico City, Mexico
| | - Magdalena Madero
- Department of Nephrology, National Institute of Cardiology “Ignacio Chavez,” Mexico City, Mexico
| | - Bernardo Rodriguez-Iturbe
- Department of Nephrology, National Institute of Cardiology "Ignacio Chavez," Mexico City, Mexico .,Department of Nephrology and Mineral Metabolism, National Institute of Health Sciences and Nutrition "Salvador Zubirán," Mexico City, Mexico
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8
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Peixoto-Neves D, Kanthakumar P, Afolabi JM, Soni H, Buddington RK, Adebiyi A. K V7.1 channel blockade inhibits neonatal renal autoregulation triggered by a step decrease in arterial pressure. Am J Physiol Renal Physiol 2022; 322:F197-F207. [PMID: 35001664 PMCID: PMC8816635 DOI: 10.1152/ajprenal.00568.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
KV7 channels, the voltage-gated K+ channels encoded by KCNQ genes, mediate heterogeneous vascular responses in rodents. Postnatal changes in the functional expression of KV7 channels have been reported in rodent saphenous arteries, but their physiological function in the neonatal renal vascular bed is unclear. Here, we report that, unlike adult pigs, only KCNQ1 (KV7.1) out of the five members of KCNQ genes was detected in neonatal pig renal microvessels. KCNQ1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. Activation of renal vascular smooth muscle cell (SMC) KV7.1 stimulated whole cell currents, inhibited by HMR1556 (HMR), a selective KV7.1 blocker. HMR did not change the steady-state diameter of isolated renal microvessels. Similarly, intrarenal artery infusion of HMR did not alter mean arterial pressure, renal blood flow, and renal vascular resistance in the pigs. An ∼20 mmHg reduction in mean arterial pressure evoked effective autoregulation of renal blood flow, which HMR inhibited. We conclude that 1) the expression of KCNQ isoforms in porcine renal microvessels is dependent on kidney maturation, 2) KV7.1 is functionally expressed in neonatal pig renal vascular SMCs, 3) a decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs, and 4) SMC KV7.1 does not control basal renal vascular tone but contributes to neonatal renal autoregulation triggered by a step decrease in arterial pressure.NEW & NOTEWORTHY KV7.1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. KV7.1 is functionally expressed in neonatal pig renal vascular smooth muscle cells (SMCs). A decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs. Although SMC KV7.1 does not control basal renal vascular resistance, its inhibition blunts neonatal renal autoregulation engendered by a step decrease in arterial pressure.
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Affiliation(s)
- Dieniffer Peixoto-Neves
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Jeremiah M. Afolabi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Hitesh Soni
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Adebowale Adebiyi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
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9
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Marcoux AA, Tremblay LE, Slimani S, Fiola MJ, Mac-Way F, Haydock L, Garneau AP, Isenring P. Anatomophysiology of the Henle's Loop: Emphasis on the Thick Ascending Limb. Compr Physiol 2021; 12:3119-3139. [PMID: 34964111 DOI: 10.1002/cphy.c210021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The loop of Henle plays a variety of important physiological roles through the concerted actions of ion transport systems in both its apical and basolateral membranes. It is involved most notably in extracellular fluid volume and blood pressure regulation as well as Ca2+ , Mg2+ , and acid-base homeostasis because of its ability to reclaim a large fraction of the ultrafiltered solute load. This nephron segment is also involved in urinary concentration by energizing several of the steps that are required to generate a gradient of increasing osmolality from cortex to medulla. Another important role of the loop of Henle is to sustain a process known as tubuloglomerular feedback through the presence of specialized renal tubular cells that lie next to the juxtaglomerular arterioles. This article aims at describing these physiological roles and at discussing a number of the molecular mechanisms involved. It will also report on novel findings and uncertainties regarding the realization of certain processes and on the pathophysiological consequences of perturbed salt handling by the thick ascending limb of the loop of Henle. Since its discovery 150 years ago, the loop of Henle has remained in the spotlight and is now generating further interest because of its role in the renal-sparing effect of SGLT2 inhibitors. © 2022 American Physiological Society. Compr Physiol 12:1-21, 2022.
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Affiliation(s)
- Andrée-Anne Marcoux
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Laurence E Tremblay
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Samira Slimani
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Marie-Jeanne Fiola
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Fabrice Mac-Way
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Ludwig Haydock
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Alexandre P Garneau
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada.,Cardiometabolic Axis, School of Kinesiology and Physical Activity Sciences, University of Montréal, Montréal, QC, Canada
| | - Paul Isenring
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
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10
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Olesen ETB, Fenton RA. Aquaporin 2 regulation: implications for water balance and polycystic kidney diseases. Nat Rev Nephrol 2021; 17:765-781. [PMID: 34211154 DOI: 10.1038/s41581-021-00447-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2021] [Indexed: 02/06/2023]
Abstract
Targeting the collecting duct water channel aquaporin 2 (AQP2) to the plasma membrane is essential for the maintenance of mammalian water homeostasis. The vasopressin V2 receptor (V2R), which is a GS protein-coupled receptor that increases intracellular cAMP levels, has a major role in this targeting process. Although a rise in cAMP levels and activation of protein kinase A are involved in facilitating the actions of V2R, studies in knockout mice and cell models have suggested that cAMP signalling pathways are not an absolute requirement for V2R-mediated AQP2 trafficking to the plasma membrane. In addition, although AQP2 phosphorylation is a known prerequisite for V2R-mediated plasma membrane targeting, none of the known AQP2 phosphorylation events appears to be rate-limiting in this process, which suggests the involvement of other factors; cytoskeletal remodelling has also been implicated. Notably, several regulatory processes and signalling pathways involved in AQP2 trafficking also have a role in the pathophysiology of autosomal dominant polycystic kidney disease, although the role of AQP2 in cyst progression is unknown. Here, we highlight advances in the field of AQP2 regulation that might be exploited for the treatment of water balance disorders and provide a rationale for targeting these pathways in autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Endocrinology and Nephrology, North Zealand Hospital, Hillerød, Denmark.
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus, Denmark.
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11
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Alvira-Iraizoz F, Gillard BT, Lin P, Paterson A, Pauža AG, Ali MA, Alabsi AH, Burger PA, Hamadi N, Adem A, Murphy D, Greenwood MP. Multiomic analysis of the Arabian camel (Camelus dromedarius) kidney reveals a role for cholesterol in water conservation. Commun Biol 2021; 4:779. [PMID: 34163009 PMCID: PMC8222267 DOI: 10.1038/s42003-021-02327-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 06/06/2021] [Indexed: 02/05/2023] Open
Abstract
The Arabian camel (Camelus dromedarius) is the most important livestock animal in arid and semi-arid regions and provides basic necessities to millions of people. In the current context of climate change, there is renewed interest in the mechanisms that enable camelids to survive in arid conditions. Recent investigations described genomic signatures revealing evolutionary adaptations to desert environments. We now present a comprehensive catalogue of the transcriptomes and proteomes of the dromedary kidney and describe how gene expression is modulated as a consequence of chronic dehydration and acute rehydration. Our analyses suggested an enrichment of the cholesterol biosynthetic process and an overrepresentation of categories related to ion transport. Thus, we further validated differentially expressed genes with known roles in water conservation which are affected by changes in cholesterol levels. Our datasets suggest that suppression of cholesterol biosynthesis may facilitate water retention in the kidney by indirectly facilitating the AQP2-mediated water reabsorption.
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Affiliation(s)
- Fernando Alvira-Iraizoz
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK.
| | - Benjamin T Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Panjiao Lin
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Alex Paterson
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Audrys G Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Mahmoud A Ali
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, AL Ain, United Arab Emirates
| | - Ammar H Alabsi
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Pamela A Burger
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, Vetmeduni Vienna, Vienna, Austria
| | - Naserddine Hamadi
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates
| | - Abdu Adem
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, AL Ain, United Arab Emirates.
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
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12
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Souza VC, Aguilar M, Van Amburgh M, Nayananjalie WAD, Hanigan MD. Milk urea nitrogen variation explained by differences in urea transport into the gastrointestinal tract in lactating dairy cows. J Dairy Sci 2021; 104:6715-6726. [PMID: 33773787 DOI: 10.3168/jds.2020-19787] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/13/2021] [Indexed: 01/30/2023]
Abstract
Milk urea nitrogen (MUN) and blood urea nitrogen are correlated with nitrogen balance and nitrogen excretion; however, there is also a genetic component to MUN concentrations that could be associated with differences in urea transport. It was hypothesized that a portion of the variation in MUN concentrations among cows is caused by variation in gastrointestinal and kidney urea clearance rates. Eight lactating cows with varying MUN concentrations while fed a common diet were infused with [15N15N]urea to determine urea N entry rate (UER), gastrointestinal entry rate, returned to ornithine cycle, urea N used for anabolism, urea N excretion in feces and urine. Urea clearance rates by the kidneys and gastrointestinal tract were calculated from isotopic enrichment of urea excretion in urine and gut entry rate, respectively, and plasma urea N concentrations (PUN). Over the course of the experiment, animals weighed an average of 506 ± 62 kg and produced 26.3 ± 4.39 kg of milk/d, with MUN concentrations ranging from 11.6 to 17.3 mg/dL (average of 14.9 ± 2.1 mg/dL). Plasma urea N was positively correlated with UER, urea N excretion in urine, and urea N used for anabolism. Plasma urea N and MUN were negatively correlated with gut clearance rates and ratio of gastrointestinal entry rate to UER. This relationship supports the hypothesis that differences in gut urea transport activity among animals causes variation in PUN and MUN concentrations, and that cows with high PUN and MUN are less efficient at recycling PUN to the gastrointestinal tract and thus may be more susceptible to ruminal N deficiencies when fed low RDP diets. Such biological variation in urea metabolism necessitates an adequate safety margin when setting regulations for maximal MUN levels as an indicator of herd N efficiency.
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Affiliation(s)
- V C Souza
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061
| | - M Aguilar
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061
| | - M Van Amburgh
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - W A D Nayananjalie
- Department of Animal and Food Sciences, Faculty of Agriculture, Rajarata University of Sri Lanka, Puliyankulama, Anuradhapura, Sri Lanka 61316
| | - M D Hanigan
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061.
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13
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Woloshuk A, Khochare S, Almulhim AF, McNutt AT, Dean D, Barwinska D, Ferkowicz MJ, Eadon MT, Kelly KJ, Dunn KW, Hasan MA, El-Achkar TM, Winfree S. In Situ Classification of Cell Types in Human Kidney Tissue Using 3D Nuclear Staining. Cytometry A 2020; 99:707-721. [PMID: 33252180 DOI: 10.1002/cyto.a.24274] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/29/2020] [Accepted: 11/26/2020] [Indexed: 12/30/2022]
Abstract
To understand the physiology and pathology of disease, capturing the heterogeneity of cell types within their tissue environment is fundamental. In such an endeavor, the human kidney presents a formidable challenge because its complex organizational structure is tightly linked to key physiological functions. Advances in imaging-based cell classification may be limited by the need to incorporate specific markers that can link classification to function. Multiplex imaging can mitigate these limitations, but requires cumulative incorporation of markers, which may lead to tissue exhaustion. Furthermore, the application of such strategies in large scale 3-dimensional (3D) imaging is challenging. Here, we propose that 3D nuclear signatures from a DNA stain, DAPI, which could be incorporated in most experimental imaging, can be used for classifying cells in intact human kidney tissue. We developed an unsupervised approach that uses 3D tissue cytometry to generate a large training dataset of nuclei images (NephNuc), where each nucleus is associated with a cell type label. We then devised various supervised machine learning approaches for kidney cell classification and demonstrated that a deep learning approach outperforms classical machine learning or shape-based classifiers. Specifically, a custom 3D convolutional neural network (NephNet3D) trained on nuclei image volumes achieved a balanced accuracy of 80.26%. Importantly, integrating NephNet3D classification with tissue cytometry allowed in situ visualization of cell type classifications in kidney tissue. In conclusion, we present a tissue cytometry and deep learning approach for in situ classification of cell types in human kidney tissue using only a DNA stain. This methodology is generalizable to other tissues and has potential advantages on tissue economy and non-exhaustive classification of different cell types.
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Affiliation(s)
- Andre Woloshuk
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Suraj Khochare
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Aljohara F Almulhim
- Department of Computer Science, Indiana University Purdue University, Indianapolis, Indiana, USA
| | - Andrew T McNutt
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Dawson Dean
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Daria Barwinska
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Michael J Ferkowicz
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Michael T Eadon
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Katherine J Kelly
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Department of Medicine, Indianapolis VA Medical Center, Indianapolis, Indiana, USA
| | - Kenneth W Dunn
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Mohammad A Hasan
- Department of Computer Science, Indiana University Purdue University, Indianapolis, Indiana, USA
| | - Tarek M El-Achkar
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Department of Medicine, Indianapolis VA Medical Center, Indianapolis, Indiana, USA.,Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Seth Winfree
- Department of Medicine, Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Department of Medicine, Indianapolis VA Medical Center, Indianapolis, Indiana, USA.,Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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14
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Zhang C, Chen Y, Sun S, Zhang Y, Wang L, Luo Z, Liu M, Dong L, Dong N, Wu Q. A conserved LDL-receptor motif regulates corin and CD320 membrane targeting in polarized renal epithelial cells. eLife 2020; 9:56059. [PMID: 33136001 PMCID: PMC7605860 DOI: 10.7554/elife.56059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 10/19/2020] [Indexed: 12/27/2022] Open
Abstract
Selective protein distribution on distinct plasma membranes is important for epithelial cell function. To date, how proteins are directed to specific epithelial cell surface is not fully understood. Here we report a conserved DSSDE motif in LDL-receptor (LDLR) modules of corin (a transmembrane serine protease) and CD320 (a receptor for vitamin B12 uptake), which regulates apical membrane targeting in renal epithelial cells. Altering this motif prevents specific apical corin and CD320 expression in polarized Madin-Darby canine kidney (MDCK) cells. Mechanistic studies indicate that this DSSDE motif participates in a Rab11a-dependent mechanism that specifies apical sorting. In MDCK cells, inhibition of Rab11a, but not Rab11b, expression leads to corin and CD320 expression on both apical and basolateral membranes. Together, our results reveal a novel molecular recognition mechanism that regulates LDLR module-containing proteins in their specific apical expression in polarized renal epithelial cells.
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Affiliation(s)
- Ce Zhang
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China
| | - Yue Chen
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China
| | - Shijin Sun
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China.,MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yikai Zhang
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China.,MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Lina Wang
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China
| | - Zhipu Luo
- Institute of Molecular Enzymology, Soochow University, Suzhou, China
| | - Meng Liu
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China
| | - Liang Dong
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China
| | - Ningzheng Dong
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China.,MOH Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Qingyu Wu
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Prevention, Soochow University, Suzhou, China.,Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, United States
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15
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Fasoli S, Andreani G, Dondi F, Ferlizza E, Bellei E, Isani G. Urinary Reference Values and First Insight into the Urinary Proteome of Captive Giraffes. Animals (Basel) 2020; 10:E1696. [PMID: 32961670 PMCID: PMC7552697 DOI: 10.3390/ani10091696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 11/16/2022] Open
Abstract
Urinalysis is widely recognized to be a useful tool in routine health investigations, since it can diagnose numerous pathologies. Considering the paucity of knowledge concerning giraffes, urine from 44 giraffes (Giraffa camelopardalis) (18 males and 26 females, from 3 months of age to 21 years of age) underwent routine urinalysis, 1D-electrophoresis, and protein identification using mass spectrometry, with the aim of identifying the urinary reference values and the urine proteome. The urine specific gravity (USG), urine total proteins (uTP), urine creatinine (uCr), and urine protein:creatinine ratio (UPC) reference values, reported as the median, and lower limit (LL) and upper limit (UL), were 1.030 (1006-1.049), 17.58 (4.54-35.31) mg/dL, 154.62 (39.59-357.95) mg/dL, and 0.11 (0.07-0.16), respectively. Mass spectrometry, together with electrophoresis, revealed a pattern of common urinary proteins; albumin, lysozyme C, and ubiquitin were the most represented proteins in the giraffe urine. It has been hypothesized that these proteins could act as a defense against microbes. Moreover, in giraffes, urinalysis could be a valid tool for gauging renal function and physiological status changes.
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Affiliation(s)
- Sabrina Fasoli
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, 40064 Bologna, Italy; (S.F.); (F.D.); (G.I.)
| | - Giulia Andreani
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, 40064 Bologna, Italy; (S.F.); (F.D.); (G.I.)
| | - Francesco Dondi
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, 40064 Bologna, Italy; (S.F.); (F.D.); (G.I.)
| | - Enea Ferlizza
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, 40126 Bologna, Italy;
| | - Elisa Bellei
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance, Proteomic Lab, University of Modena and Reggio Emilia, 41124 Modena, Italy;
| | - Gloria Isani
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, 40064 Bologna, Italy; (S.F.); (F.D.); (G.I.)
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16
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Fenton RA, Murali SK, Moeller HB. Advances in aquaporin-2 trafficking mechanisms and their implications for treatment of water balance disorders. Am J Physiol Cell Physiol 2020; 319:C1-C10. [PMID: 32432927 DOI: 10.1152/ajpcell.00150.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In mammals, conservation of body water is critical for survival and is dependent on the kidneys' ability to minimize water loss in the urine during periods of water deprivation. The collecting duct water channel aquaporin-2 (AQP2) plays an essential role in this homeostatic response by facilitating water reabsorption along osmotic gradients. The ability to increase the levels of AQP2 in the apical plasma membrane following an increase in plasma osmolality is a rate-limiting step in water reabsorption, a process that is tightly regulated by the antidiuretic hormone arginine vasopressin (AVP). In this review, the focus is on the role of the carboxyl-terminus of AQP2 as a key regulatory point for AQP2 trafficking. We provide an overview of AQP2 structure, disease-causing mutations in the AQP2 carboxyl-terminus, the role of posttranslational modifications such as phosphorylation and ubiquitylation in the tail domain, and their implications for balanced trafficking of AQP2. Finally, we discuss how various modifications of the AQP2 tail facilitate selective protein-protein interactions that modulate the AQP2 trafficking mechanism.
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Affiliation(s)
- Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Hanne B Moeller
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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17
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Laszczyk AM, Higashi AY, Patel SR, Johnson CN, Soofi A, Abraham S, Dressler GR. Pax2 and Pax8 Proteins Regulate Urea Transporters and Aquaporins to Control Urine Concentration in the Adult Kidney. J Am Soc Nephrol 2020; 31:1212-1225. [PMID: 32381599 PMCID: PMC7269349 DOI: 10.1681/asn.2019090962] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/29/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND As the glomerular filtrate passes through the nephron and into the renal medulla, electrolytes, water, and urea are reabsorbed through the concerted actions of solute carrier channels and aquaporins at various positions along the nephron and in the outer and inner medulla. Proliferating stem cells expressing the nuclear transcription factor Pax2 give rise to renal epithelial cells. Pax2 expression ends once the epithelial cells differentiate into mature proximal and distal tubules, whereas expression of the related Pax8 protein continues. The collecting tubules and renal medulla are derived from Pax2-positive ureteric bud epithelia that continue to express Pax2 and Pax8 in adult kidneys. Despite the crucial role of Pax2 in renal development, functions for Pax2 or Pax8 in adult renal epithelia have not been established. METHODS To examine the roles of Pax2 and Pax8 in the adult mouse kidney, we deleted either Pax2, Pax8, or both genes in adult mice and examined the resulting phenotypes and changes in gene expression patterns. We also explored the mechanism of Pax8-mediated activation of potential target genes in inner medullary collecting duct cells. RESULTS Mice with induced deletions of both Pax2 and Pax8 exhibit severe polyuria that can be attributed to significant changes in the expression of solute carriers, such as the urea transporters encoded by Slc14a2, as well as aquaporins within the inner and outer medulla. Furthermore, Pax8 expression is induced by high-salt levels in collecting duct cells and activates the Slc14a2 gene by recruiting a histone methyltransferase complex to the promoter. CONCLUSIONS These data reveal novel functions for Pax proteins in adult renal epithelia that are essential for retaining water and concentrating urine.
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Affiliation(s)
- Ann M Laszczyk
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Atsuko Y Higashi
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | | | - Craig N Johnson
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Abdul Soofi
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Saji Abraham
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
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18
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Abdalla M. Anatomical features in the kidney involved in water conservation through urine concentration in dromedaries ( Camelus dromedarius). Heliyon 2020; 6:e03139. [PMID: 31922050 PMCID: PMC6948238 DOI: 10.1016/j.heliyon.2019.e03139] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/13/2019] [Accepted: 12/27/2019] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to report some of the morphological characteristics of the kidney involved in urine concentration and hence water conservation in the dromedaries. A total of 20 fresh kidneys of 10 apparently healthy camels were used in this study. The architecture of the renal pelvis was revealed by dissection and polyvinyl chloride corrosion casts. Samples were also processed for histology and for enzyme histochemistry. The camel kidney is bean shaped, smooth, multilobar, unipapillary, in which the fusion of renal papillae is complete forming a common renal papilla or crest, which channel urine into a central renal pelvis. It is more or less similar to equine, caprine, ovine and canine kidney. Under certain anatomical requisites the renal pelvis is known to play a role in urine concentration through recycling of urea to increase the medullary osmotic concentration which favors the counter-current mechanism. One of these requisites is an elaborate renal pelvis which is closely associated with the renal medulla. The renal pelvis of the camel has a main crescentic cavity following the long axis and curvature of the kidney. A thick extensive renal crest projects into the cavity of the pelvis. The thick renal crest contains large numbers of long loops of Henle and vasa recta which are important for urine concentration. The renal crest is formed by convergence of the medullary pyramids before it projects into the cavity of the renal pelvis. The crescentic main cavity of the pelvis forms 20-24 three dimensional radiating collateral recesses which contain the medullary pyramids. This close association of the renal pelvis and medulla provide a large surface area for the recycling of urea and hence urine concentration. This large pelvic-medullary interface is lined by simple low cuboidal epithelium which enhances the recycling of urea and water from the pelvic urine into the medulla and directly contributes to urine concentration. The rest of the wall of the renal pelvis and its recesses facing away from the renal crest and medullary pyramids is lined by impermeable transitional epithelium. Another feature is the intense activity of alkaline phosphatase demonstrated in the proximal convoluted tubules which indicates increased membrane transport. It is concluded that the kidney in dromedaries has the anatomical and histochemical requisites for the production of concentrated urine. These requisites enable the kidney to adequately contribute to the ability of the camel to conserve water and withstand the aridity of its habitat.
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Affiliation(s)
- M.A. Abdalla
- Department of Anatomy, Faculty of Medicine, University of Khartoum, Sudan
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19
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Thomas SR. Mathematical models for kidney function focusing on clinical interest. Morphologie 2019; 103:161-168. [PMID: 31722814 DOI: 10.1016/j.morpho.2019.10.043] [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] [Received: 10/08/2019] [Accepted: 10/11/2019] [Indexed: 01/22/2023]
Abstract
We give an overview of mathematical models of renal physiology and anatomy with the clinician in mind. Beyond the past focus on issues of local transport mechanisms along the nephron and the urine concentrating mechanism, recent models have brought insight into difficult problems such as renal ischemia (oxygen and CO2 diffusion in the medulla) or calcium and potassium homeostasis. They have also provided revealing 3D reconstructions of the full trajectories of families of nephrons and collecting ducts through cortex and medulla. The recent appearance of sophisticated whole-kidney models representing nephrons and their associated renal vasculature promises more realistic simulation of renal pathologies and pharmacological treatments in the foreseeable future.
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Affiliation(s)
- S Randall Thomas
- Inserm, LTSI - UMR 1099, Université Rennes, 35000 Rennes, France.
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20
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Gee MT, Kurtz I, Pannabecker TL. Expression of SLC4A11 protein in mouse and rat medulla: a candidate transporter involved in outer medullary ammonia recycling. Physiol Rep 2019; 7:e14089. [PMID: 31124301 PMCID: PMC6533174 DOI: 10.14814/phy2.14089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 04/10/2019] [Indexed: 01/27/2023] Open
Abstract
SLC4A11 is a multifunctional membrane transporter involved with H+ transport, NH3 and alkaline pH stimulated H+ transport, and water transport. The role of SLC4A11 in the kidney is not well understood. A prior study has shown that in murine kidney, SLC4A11/LacZ staining is primarily in the long-looped descending thin limb (DTL) as determined by colocalization with aquaporin 1 (AQP1), a protein that is expressed in some, but not all, descending thin limb segments. Using a previously characterized polyclonal antibody, we demonstrate the selective expression of SLC4A11 in the upper DTLs (which are AQP1-positive) in the outer medulla and inner medulla with little or no expression in the lower DTLs (which are AQP-1-null). SLC4A11 also colocalized with AQP1 and the urea transporter UT-B in the mouse descending vasa recta, but was absent in mouse and rat ascending vasa recta. Mouse, but not rat, outer medullary collecting duct cells also labeled for SLC4A11. Our results are compatible with the hypothesis that in the inner stripe of the outer medulla, SLC4A11 plays a role in the countercurrent transport of ammonia absorbed from the outer medullary thick ascending limb and secreted into the long-looped DTLs. SLC4A11 can potentially modulate the rate of ammonia transport in the mouse outer medullary collecting duct. Our data suggest functionally unique SLC4A11 pathways in mouse and rat and complement previous studies of DTL Na+ , urea and water permeability indicating that the upper and lower DTLs of long-looped nephrons are functionally distinct.
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Affiliation(s)
- Michael T. Gee
- Department of PhysiologyBanner‐University Medical CenterUniversity of ArizonaTucsonAZ85724
| | - Ira Kurtz
- Division of NephrologyDavid Geffen School of MedicineUniversity of California, Los Angeles (UCLA)Los AngelesCA
- Brain Research InstituteDavid Geffen School of MedicineUniversity of California, Los Angeles (UCLA)Los AngelesCA
| | - Thomas L. Pannabecker
- Department of PhysiologyBanner‐University Medical CenterUniversity of ArizonaTucsonAZ85724
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21
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Goertz CEC, Reichmuth C, Thometz NM, Ziel H, Boveng P. Comparative Health Assessments of Alaskan Ice Seals. Front Vet Sci 2019; 6:4. [PMID: 30792982 PMCID: PMC6375287 DOI: 10.3389/fvets.2019.00004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 01/10/2019] [Indexed: 01/07/2023] Open
Abstract
Bearded (Erignathus barbatus), ringed (Pusa hispida), spotted (Phoca largha), and ribbon (Histriophoca fasciata) seals rely on seasonal sea-ice in Arctic and sub-Arctic regions. Many aspects of the biology and physiology of these seals are poorly known, and species-typical health parameters are not available for all species. Such information has proven difficult to obtain due to the challenges of studying Arctic seals in the wild and their minimal historic representation in aquaria. Here, we combine diagnostic information gathered between 2000 and 2017 from free-ranging seals, seals in short-term rehabilitation, and seals living in long-term human care to evaluate and compare key health parameters. For individuals in apparent good health, hematology, and blood chemistry values are reported by the source group for 10 bearded, 13 ringed, 73 spotted, and 81 ribbon seals from Alaskan waters. For a smaller set of individuals handled during veterinary or necropsy procedures, the presence of parasites and pathogens is described, as well as exposure to a variety of infectious diseases known to affect marine mammals and/or humans, with positive titers observed for Brucella, Leptospira, avian influenza, herpesvirus PhHV-1, and morbillivirus. These data provide initial baseline parameters for hematology, serum chemistries, and other species-level indicators of health that can be used to assess the condition of individual seals, inform monitoring and management efforts, and guide directed research efforts for Alaskan populations of ice-associated seals.
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Affiliation(s)
| | - Colleen Reichmuth
- Alaska SeaLife Center, Seward, AK, United States.,Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Nicole M Thometz
- Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States.,Department of Biology, University of San Francisco, San Francisco, CA, United States
| | - Heather Ziel
- Polar Ecosystems Program, Marine Mammal Laboratory, Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, WA, United States
| | - Peter Boveng
- Polar Ecosystems Program, Marine Mammal Laboratory, Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, WA, United States
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