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Stocker SD, Kinsman BJ, Farquhar WB, Gyarmati G, Peti-Peterdi J, Sved AF. Physiological Mechanisms of Dietary Salt Sensing in the Brain, Kidney, and Gastrointestinal Tract. Hypertension 2024; 81:447-455. [PMID: 37671571 PMCID: PMC10915107 DOI: 10.1161/hypertensionaha.123.19488] [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] [Indexed: 09/07/2023]
Abstract
Excess dietary salt (NaCl) intake is strongly correlated with cardiovascular disease and is a major contributing factor to the pathogenesis of hypertension. NaCl-sensitive hypertension is a multisystem disorder that involves renal dysfunction, vascular abnormalities, and neurogenically-mediated increases in peripheral resistance. Despite a major research focus on organ systems and these effector mechanisms causing NaCl-induced increases in arterial blood pressure, relatively less research has been directed at elucidating how NaCl is sensed by various tissues to elicit these downstream effects. The purpose of this review is to discuss how the brain, kidney, and gastrointestinal tract sense NaCl including key cell types, the role of NaCl versus osmolality, and the underlying molecular and electrochemical mechanisms.
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Affiliation(s)
- Sean D. Stocker
- Department of Neurobiology, University of Pittsburgh School of Medicine
| | - Brian J Kinsman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital
| | | | - Georgina Gyarmati
- Department of Physiology and Neuroscience and Medicine, Zilkha Neurogenetic Institute, University of Southern California
| | - Janos Peti-Peterdi
- Department of Physiology and Neuroscience and Medicine, Zilkha Neurogenetic Institute, University of Southern California
| | - Alan F. Sved
- Department of Neuroscience, University of Pittsburgh
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2
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Wang SX, Streit A. Shared features in ear and kidney development - implications for oto-renal syndromes. Dis Model Mech 2024; 17:dmm050447. [PMID: 38353121 PMCID: PMC10886756 DOI: 10.1242/dmm.050447] [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] [Indexed: 02/16/2024] Open
Abstract
The association between ear and kidney anomalies has long been recognized. However, little is known about the underlying mechanisms. In the last two decades, embryonic development of the inner ear and kidney has been studied extensively. Here, we describe the developmental pathways shared between both organs with particular emphasis on the genes that regulate signalling cross talk and the specification of progenitor cells and specialised cell types. We relate this to the clinical features of oto-renal syndromes and explore links to developmental mechanisms.
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Affiliation(s)
- Scarlet Xiaoyan Wang
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
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3
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Andrini O, Eladari D, Picard N. ClC-K Kidney Chloride Channels: From Structure to Pathology. Handb Exp Pharmacol 2024; 283:35-58. [PMID: 36811727 DOI: 10.1007/164_2023_635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The molecular basis of chloride transport varies all along the nephron depending on the tubular segments especially in the apical entry of the cell. The major chloride exit pathway during reabsorption is provided by two kidney-specific ClC chloride channels ClC-Ka and ClC-Kb (encoded by CLCNKA and CLCNKB gene, respectively) corresponding to rodent ClC-K1 and ClC-K2 (encoded by Clcnk1 and Clcnk2). These channels function as dimers and their trafficking to the plasma membrane requires the ancillary protein Barttin (encoded by BSND gene). Genetic inactivating variants of the aforementioned genes lead to renal salt-losing nephropathies with or without deafness highlighting the crucial role of ClC-Ka, ClC-Kb, and Barttin in the renal and inner ear chloride handling. The purpose of this chapter is to summarize the latest knowledge on renal chloride structure peculiarity and to provide some insight on the functional expression on the segments of the nephrons and on the related pathological effects.
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Affiliation(s)
- Olga Andrini
- Univ Lyon, University Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U 1314, Melis, Lyon, France.
| | - Dominique Eladari
- CHU Amiens Picardie, Service de Médecine de Précision des maladies Métaboliques et Rénales, Université de Picardie Jules Verne, Amiens, France
| | - Nicolas Picard
- CNRS, LBTI UMR5305, Université Claude Bernard Lyon 1, Lyon, France
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4
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Lindner ML, Lohmeyer JL, Adam EH, Zacharowski K, Weber CF. [Mechanisms of action and clinical application of diuretics in intensive care medicine]. DIE ANAESTHESIOLOGIE 2023; 72:757-770. [PMID: 37768358 DOI: 10.1007/s00101-023-01338-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/12/2023] [Indexed: 09/29/2023]
Abstract
The paired kidneys play a significant role in the human body due to the multitude of physiological tasks. Complex biochemical processes keep the sensitive electrolyte and water balance stable and thus ensure the organism's ability to adapt to exogenous and endogenous factors, which is essential for survival. The drug class of diuretics includes substances with very differing pharmacological characteristics. The functioning of the nephron is therefore indispensable for a deeper understanding of the pharmacodynamics, pharmacokinetics and side effect profile of diuretics. In the treatment of acute heart failure with pulmonary congestion, certain diuretics represent an important therapeutic option to counteract hypervolemia and thus an increase in preload. According to current data, diuretics have no proven benefits in the treatment or prevention of acute kidney injury but they can counteract hypervolemia and under certain conditions even reduce the use of renal replacement procedures.
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Affiliation(s)
- M-L Lindner
- Abteilung für Anästhesiologie, Intensiv- und Notfallmedizin, Asklepios Kliniken Hamburg GmbH, Asklepios Klinik Wandsbek, Alphonsstraße 14, 22043, Hamburg, Deutschland.
| | - J L Lohmeyer
- Abteilung für Anästhesiologie, Intensiv‑, Notfall-, und Schmerzmedizin, Asklepios Kliniken Hamburg GmbH, Asklepios Klinik Altona, Paul-Ehrlich-Straße 1, 22763, Hamburg, Deutschland
| | - E H Adam
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Frankfurt, Goethe-Universität, Theodor Stern Kai 7, 60590, Frankfurt, Deutschland
| | - K Zacharowski
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Frankfurt, Goethe-Universität, Theodor Stern Kai 7, 60590, Frankfurt, Deutschland
| | - C F Weber
- Abteilung für Anästhesiologie, Intensiv- und Notfallmedizin, Asklepios Kliniken Hamburg GmbH, Asklepios Klinik Wandsbek, Alphonsstraße 14, 22043, Hamburg, Deutschland
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Frankfurt, Goethe-Universität, Theodor Stern Kai 7, 60590, Frankfurt, Deutschland
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5
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Tossetta G, Fantone S, Senzacqua M, Galosi AB, Marzioni D, Morroni M. ZO-1 expression in normal human macula densa: Immunohistochemical and immunofluorescence investigations. J Anat 2023; 242:1184-1188. [PMID: 36719664 PMCID: PMC10184539 DOI: 10.1111/joa.13832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 02/01/2023] Open
Abstract
The macula densa (MD) is an anatomical structure having a plaque shape, placed in the distal end of thick ascending limb of each nephron and belonging to juxtaglomerular apparatus (JGA). The aim of the present investigation is to investigate the presence of ZO-1, a specific marker of tight juncions (TJs), in MD cells. Six samples of normal human renal tissue were embedded in paraffin for ZO-1 expression analysis by immunohistochemical and immunofluorescence techniques. We detected ZO-1 expression in the apical part of cell membrane in MD cells by immunohistochemistry. In addition, ZO-1 and nNOS expressions (a specific marker of MD) were colocalized in MD cells providing clear evidence of TJs presence in normal human MD. Since ZO-1 is responsible for diffusion barrier formation, its presence in the MD supports the existence of a tubulomesangial barrier that ensures a regulated exchange between MD and JGA effectors in renal and glomerular haemodynamic homeostasis.
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Affiliation(s)
- Giovanni Tossetta
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Sonia Fantone
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Martina Senzacqua
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Andrea Benedetto Galosi
- Division of Urology, Department of Clinical and Specialist Sciences, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy
| | - Daniela Marzioni
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Manrico Morroni
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Ancona, Italy
- Electron Microscopy Unit, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy
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6
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Suh SH, Oh TR, Choi HS, Kim CS, Bae EH, Ma SK, Oh KH, Yoo TH, Chae DW, Kim SW. Association between urinary chloride excretion and progression of coronary artery calcification in patients with nondialysis chronic kidney disease: results from the KNOW-CKD study. Kidney Res Clin Pract 2023; 42:251-261. [PMID: 36908202 PMCID: PMC10085721 DOI: 10.23876/j.krcp.22.072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 03/14/2023] Open
Abstract
BACKGROUND Urine chloride has recently been suggested as a biomarker of renal tubule function in patients with nondialysis chronic kidney disease (CKD), as low urinary chloride concentration is associated with an increased risk of CKD progression. We investigate the association between urinary chloride excretion and the progression of coronary artery calcification (CAC). METHODS A total of 1,065 patients with nondialysis CKD were divided into tertiles by spot urine chloride-to-creatinine ratios. The 1st, 2nd, and 3rd tertiles were defined as low, moderate, and high urinary chloride excretion, respectively. The study outcome was CAC progression, which was defined as an increase in coronary artery calcium score of more than 200 Agatston units during the 4-year follow-up period. RESULTS Compared to moderate urinary chloride excretion, high urinary chloride excretion was associated with decreased risk of CAC progression (adjusted odds ratio, 0.379; 95% confidence interval, 0.190-0.757), whereas low urinary chloride excretion was not associated with risk of CAC progression. Restricted cubic spine depicted an inverted J-shaped curve, with a significant reduction in the risk of CAC progression in subjects with high spot urine chloride-to-creatinine ratios. CONCLUSION High urinary chloride excretion is associated with decreased risk of CAC progression in patients with nondialysis CKD.
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Affiliation(s)
- Sang Heon Suh
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Tae Ryom Oh
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Hong Sang Choi
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Chang Seong Kim
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Seong Kwon Ma
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Tae-Hyun Yoo
- Department of Internal Medicine and Institute of Kidney Disease Research, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Dong-Wan Chae
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - on behalf of the Korean Cohort Study for Outcomes in Patients With Chronic Kidney Disease (KNOW-CKD) Investigators
- Department of Internal Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Internal Medicine and Institute of Kidney Disease Research, Yonsei University College of Medicine, Seoul, Republic of Korea
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
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7
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Norepinephrine May Exacerbate Septic Acute Kidney Injury: A Narrative Review. J Clin Med 2023; 12:jcm12041373. [PMID: 36835909 PMCID: PMC9960985 DOI: 10.3390/jcm12041373] [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: 11/29/2022] [Revised: 01/30/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Sepsis, the most serious complication of infection, occurs when a cascade of potentially life-threatening inflammatory responses is triggered. Potentially life-threatening septic shock is a complication of sepsis that occurs when hemodynamic instability occurs. Septic shock may cause organ failure, most commonly involving the kidneys. The pathophysiology and hemodynamic mechanisms of acute kidney injury in the case of sepsis or septic shock remain to be elucidated, but previous studies have suggested multiple possible mechanisms or the interplay of multiple mechanisms. Norepinephrine is used as the first-line vasopressor in the management of septic shock. Studies have reported different hemodynamic effects of norepinephrine on renal circulation, with some suggesting that it could possibly exacerbate acute kidney injury caused by septic shock. This narrative review briefly covers the updates on sepsis and septic shock regarding definitions, statistics, diagnosis, and management, with an explanation of the putative pathophysiological mechanisms and hemodynamic changes, as well as updated evidence. Sepsis-associated acute kidney injury remains a major burden on the healthcare system. This review aims to improve the real-world clinical understanding of the possible adverse outcomes of norepinephrine use in sepsis-associated acute kidney injury.
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8
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Liu R, Juncos LA, Lu Y, Wei J, Zhang J, Wang L, Lai EY, Carlstrom M, Persson AEG. The Role of Macula Densa Nitric Oxide Synthase 1 Beta Splice Variant in Modulating Tubuloglomerular Feedback. Compr Physiol 2023; 13:4215-4229. [PMID: 36715280 PMCID: PMC9990375 DOI: 10.1002/cphy.c210043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Abnormalities in renal electrolyte and water excretion may result in inappropriate salt and water retention, which facilitates the development and maintenance of hypertension, as well as acid-base and electrolyte disorders. A key mechanism by which the kidney regulates renal hemodynamics and electrolyte excretion is via tubuloglomerular feedback (TGF), an intrarenal negative feedback between tubules and arterioles. TGF is initiated by an increase of NaCl delivery at the macula densa cells. The increased NaCl activates luminal Na-K-2Cl cotransporter (NKCC2) of the macula densa cells, which leads to activation of several intracellular processes followed by the production of paracrine signals that ultimately result in a constriction of the afferent arteriole and a tonic inhibition of single nephron glomerular filtration rate. Neuronal nitric oxide (NOS1) is highly expressed in the macula densa. NOS1β is the major splice variant and accounts for most of NO generation by the macula densa, which inhibits TGF response. Macula densa NOS1β-mediated modulation of TGF responses plays an essential role in control of sodium excretion, volume and electrolyte hemostasis, and blood pressure. In this article, we describe the mechanisms that regulate macula densa-derived NO and their effect on TGF response in physiologic and pathologic conditions. © 2023 American Physiological Society. Compr Physiol 13:4215-4229, 2023.
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Affiliation(s)
- Ruisheng Liu
- Department of Molecular Pharmacology & Physiology
- Hypertension and Kidney Research Center, Morsani College of Medicine, University of South Florida, Tampa, FL
| | - Luis A. Juncos
- Department of Internal Medicine, Central Arkansas Veterans Healthcare System, Little Rock, AR
| | - Yan Lu
- Division of Nephrology, University of Alabama at Birmingham, Birmingham AL
| | - Jin Wei
- Department of Molecular Pharmacology & Physiology
| | - Jie Zhang
- Department of Molecular Pharmacology & Physiology
| | - Lei Wang
- Department of Molecular Pharmacology & Physiology
| | - En Yin Lai
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China
| | - Mattias Carlstrom
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - A. Erik G Persson
- Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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9
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Mao ZH, Gao ZX, Liu Y, Liu DW, Liu ZS, Wu P. Single-cell transcriptomics: A new tool for studying diabetic kidney disease. Front Physiol 2023; 13:1053850. [PMID: 36685214 PMCID: PMC9846140 DOI: 10.3389/fphys.2022.1053850] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/16/2022] [Indexed: 01/05/2023] Open
Abstract
The kidney is a complex organ comprising various functional partitions and special cell types that play important roles in maintaining homeostasis in the body. Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease and is an independent risk factor for cardiovascular diseases. Owing to the complexity and heterogeneity of kidney structure and function, the mechanism of DKD development has not been fully elucidated. Single-cell sequencing, including transcriptomics, epigenetics, metabolomics, and proteomics etc., is a powerful technology that enables the analysis of specific cell types and states, specifically expressed genes or pathways, cell differentiation trajectories, intercellular communication, and regulation or co-expression of genes in various diseases. Compared with other omics, RNA sequencing is a more developed technique with higher utilization of tissues or samples. This article reviewed the application of single-cell transcriptomics in the field of DKD and highlighted the key signaling pathways in specific tissues or cell types involved in the occurrence and development of DKD. The comprehensive understanding of single-cell transcriptomics through single-cell RNA-seq and single-nucleus RNA-seq will provide us new insights into the pathogenesis and treatment strategy of various diseases including DKD.
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Affiliation(s)
- Zi-Hui Mao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Institute of Nephrology, Zhengzhou University, Zhengzhou, China,Henan Province Research Center for Kidney Disease, Zhengzhou, China,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zhong-Xiuzi Gao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Institute of Nephrology, Zhengzhou University, Zhengzhou, China,Henan Province Research Center for Kidney Disease, Zhengzhou, China,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Yong Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Institute of Nephrology, Zhengzhou University, Zhengzhou, China,Henan Province Research Center for Kidney Disease, Zhengzhou, China,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Dong-Wei Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Institute of Nephrology, Zhengzhou University, Zhengzhou, China,Henan Province Research Center for Kidney Disease, Zhengzhou, China,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zhang-Suo Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Institute of Nephrology, Zhengzhou University, Zhengzhou, China,Henan Province Research Center for Kidney Disease, Zhengzhou, China,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China,*Correspondence: Peng Wu, ; Zhang-Suo Liu,
| | - Peng Wu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Institute of Nephrology, Zhengzhou University, Zhengzhou, China,Henan Province Research Center for Kidney Disease, Zhengzhou, China,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China,*Correspondence: Peng Wu, ; Zhang-Suo Liu,
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10
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Staruschenko A, Ma R, Palygin O, Dryer SE. Ion channels and channelopathies in glomeruli. Physiol Rev 2023; 103:787-854. [PMID: 36007181 PMCID: PMC9662803 DOI: 10.1152/physrev.00013.2022] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/15/2022] [Accepted: 08/21/2022] [Indexed: 11/22/2022] Open
Abstract
An essential step in renal function entails the formation of an ultrafiltrate that is delivered to the renal tubules for subsequent processing. This process, known as glomerular filtration, is controlled by intrinsic regulatory systems and by paracrine, neuronal, and endocrine signals that converge onto glomerular cells. In addition, the characteristics of glomerular fluid flow, such as the glomerular filtration rate and the glomerular filtration fraction, play an important role in determining blood flow to the rest of the kidney. Consequently, disease processes that initially affect glomeruli are the most likely to lead to end-stage kidney failure. The cells that comprise the glomerular filter, especially podocytes and mesangial cells, express many different types of ion channels that regulate intrinsic aspects of cell function and cellular responses to the local environment, such as changes in glomerular capillary pressure. Dysregulation of glomerular ion channels, such as changes in TRPC6, can lead to devastating glomerular diseases, and a number of channels, including TRPC6, TRPC5, and various ionotropic receptors, are promising targets for drug development. This review discusses glomerular structure and glomerular disease processes. It also describes the types of plasma membrane ion channels that have been identified in glomerular cells, the physiological and pathophysiological contexts in which they operate, and the pathways by which they are regulated and dysregulated. The contributions of these channels to glomerular disease processes, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy, as well as the development of drugs that target these channels are also discussed.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida
- Hypertension and Kidney Research Center, University of South Florida, Tampa, Florida
- James A. Haley Veterans Hospital, Tampa, Florida
| | - Rong Ma
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Oleg Palygin
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Stuart E Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, Texas
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11
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Schnell J, Achieng M, Lindström NO. Principles of human and mouse nephron development. Nat Rev Nephrol 2022; 18:628-642. [PMID: 35869368 DOI: 10.1038/s41581-022-00598-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2022] [Indexed: 12/17/2022]
Abstract
The mechanisms underlying kidney development in mice and humans is an area of intense study. Insights into kidney organogenesis have the potential to guide our understanding of the origin of congenital anomalies and enable the assembly of genetic diagnostic tools. A number of studies have delineated signalling nodes that regulate positional identities and cell fates of nephron progenitor and precursor cells, whereas cross-species comparisons have markedly enhanced our understanding of conserved and divergent features of mammalian kidney organogenesis. Greater insights into the complex cellular movements that occur as the proximal-distal axis is established have challenged our understanding of nephron patterning and provided important clues to the elaborate developmental context in which human kidney diseases can arise. Studies of kidney development in vivo have also facilitated efforts to recapitulate nephrogenesis in kidney organoids in vitro, by providing a detailed blueprint of signalling events, cell movements and patterning mechanisms that are required for the formation of correctly patterned nephrons and maturation of physiologically functional apparatus that are responsible for maintaining human health.
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Affiliation(s)
- Jack Schnell
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at University of Southern California, Los Angeles, CA, USA
| | - MaryAnne Achieng
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at University of Southern California, Los Angeles, CA, USA
| | - Nils Olof Lindström
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at University of Southern California, Los Angeles, CA, USA.
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12
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Shroff UN, Gyarmati G, Izuhara A, Deepak S, Peti-Peterdi J. A new view of macula densa cell protein synthesis. Am J Physiol Renal Physiol 2021; 321:F689-F704. [PMID: 34693742 PMCID: PMC8714974 DOI: 10.1152/ajprenal.00222.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 11/22/2022] Open
Abstract
Macula densa (MD) cells, a chief sensory cell type in the nephron, are endowed with unique microanatomic features including a high density of protein synthetic organelles and secretory vesicles in basal cell processes ("maculapodia") that suggest a so far unknown high rate of MD protein synthesis. This study aimed to explore the rate and regulation of MD protein synthesis and their effects on glomerular function using novel transgenic mouse models, newly established fluorescence cell biology techniques, and intravital microscopy. Sox2-tdTomato kidney tissue sections and an O-propargyl puromycin incorporation-based fluorescence imaging assay showed that MD cells have the highest level of protein synthesis within the kidney cortex followed by intercalated cells and podocytes. Genetic gain of function of mammalian target of rapamycin (mTOR) signaling specifically in MD cells (in MD-mTORgof mice) or their physiological activation by low-salt diet resulted in further significant increases in the synthesis of MD proteins. Specifically, these included both classic and recently identified MD-specific proteins such as cyclooxygenase 2, microsomal prostaglandin E2 synthase 1, and pappalysin 2. Intravital imaging of the kidney using multiphoton microscopy showed significant increases in afferent and efferent arteriole and glomerular capillary diameters and blood flow in MD-mTORgof mice coupled with an elevated glomerular filtration rate. The presently identified high rate of MD protein synthesis that is regulated by mTOR signaling is a novel component of the physiological activation and glomerular hemodynamic regulatory functions of MD cells that remains to be fully characterized.NEW & NOTEWORTHY This study discovered the high rate of protein synthesis in macula densa (MD) cells by applying direct imaging techniques with single cell resolution. Physiological activation and mammalian target of rapamycin signaling played important regulatory roles in this process. This new feature is a novel component of the tubuloglomerular cross talk and glomerular hemodynamic regulatory functions of MD cells. Future work is needed to elucidate the nature and (patho)physiological role of the specific proteins synthesized by MD cells.
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Affiliation(s)
- Urvi Nikhil Shroff
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Georgina Gyarmati
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Audrey Izuhara
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Sachin Deepak
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
- Department of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - János Peti-Peterdi
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
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13
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Agarwal S, Sudhini YR, Polat OK, Reiser J, Altintas MM. Renal cell markers: lighthouses for managing renal diseases. Am J Physiol Renal Physiol 2021; 321:F715-F739. [PMID: 34632812 DOI: 10.1152/ajprenal.00182.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Kidneys, one of the vital organs in our body, are responsible for maintaining whole body homeostasis. The complexity of renal function (e.g., filtration, reabsorption, fluid and electrolyte regulation, and urine production) demands diversity not only at the level of cell types but also in their overall distribution and structural framework within the kidney. To gain an in depth molecular-level understanding of the renal system, it is imperative to discern the components of kidney and the types of cells residing in each of the subregions. Recent developments in labeling, tracing, and imaging techniques have enabled us to mark, monitor, and identify these cells in vivo with high efficiency in a minimally invasive manner. In this review, we summarize different cell types, specific markers that are uniquely associated with those cell types, and their distribution in the kidney, which altogether make kidneys so special and different. Cellular sorting based on the presence of certain proteins on the cell surface allowed for the assignment of multiple markers for each cell type. However, different studies using different techniques have found contradictions in cell type-specific markers. Thus, the term "cell marker" might be imprecise and suboptimal, leading to uncertainty when interpreting the data. Therefore, we strongly believe that there is an unmet need to define the best cell markers for a cell type. Although the compendium of renal-selective marker proteins presented in this review is a resource that may be useful to researchers, we acknowledge that the list may not be necessarily exhaustive.
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Affiliation(s)
- Shivangi Agarwal
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | | | - Onur K Polat
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | - Jochen Reiser
- Department of Internal Medicine, Rush University, Chicago, Illinois
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14
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Zhang J, Wang X, Cui Y, Jiang S, Wei J, Chan J, Thalakola A, Le T, Xu L, Zhao L, Wang L, Jiang K, Cheng F, Patel T, Buggs J, Vallon V, Liu R. Knockout of Macula Densa Neuronal Nitric Oxide Synthase Increases Blood Pressure in db/db Mice. Hypertension 2021; 78:1760-1770. [PMID: 34657443 DOI: 10.1161/hypertensionaha.121.17643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Jie Zhang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Ximing Wang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa.,Department of Radiology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China (X.W.)
| | - Yu Cui
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China (Y.C., L.Z.)
| | - Shan Jiang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Jin Wei
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Jenna Chan
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Anish Thalakola
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Thanh Le
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Lan Xu
- College of Medicine, College of Public Health (L.X.), University of South Florida, Tampa
| | - Liang Zhao
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China (Y.C., L.Z.)
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Kun Jiang
- Department of Anatomic Pathology, H. Lee Moffitt Cancer Center, Research Institute, Tampa, FL (K.J.)
| | - Feng Cheng
- Department of Pharmaceutical Science, College of Pharmacy (F.C.), University of South Florida, Tampa
| | - Trushar Patel
- Department of Urology (T.P.), University of South Florida, Tampa
| | - Jacentha Buggs
- Advanced Organ Disease and Transplantation Institute, Tampa General Hospital, FL (J.B.)
| | - Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA (V.V.)
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
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15
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Kidney Microcirculation as a Target for Innovative Therapies in AKI. J Clin Med 2021; 10:jcm10184041. [PMID: 34575154 PMCID: PMC8471583 DOI: 10.3390/jcm10184041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/29/2021] [Accepted: 09/02/2021] [Indexed: 12/19/2022] Open
Abstract
Acute kidney injury (AKI) is a serious multifactorial conditions accompanied by the loss of function and damage. The renal microcirculation plays a crucial role in maintaining the kidney’s functional and structural integrity for oxygen and nutrient supply and waste product removal. However, alterations in microcirculation and oxygenation due to renal perfusion defects, hypoxia, renal tubular, and endothelial damage can result in AKI and the loss of renal function regardless of systemic hemodynamic changes. The unique structural organization of the renal microvasculature and the presence of autoregulation make it difficult to understand the mechanisms and the occurrence of AKI following disorders such as septic, hemorrhagic, or cardiogenic shock; ischemia/reperfusion; chronic heart failure; cardiorenal syndrome; and hemodilution. In this review, we describe the organization of microcirculation, autoregulation, and pathophysiological alterations leading to AKI. We then suggest innovative therapies focused on the protection of the renal microcirculation and oxygenation to prevent AKI.
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16
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Joo YS, Kim J, Park CH, Yun HR, Park JT, Chang TI, Yoo TH, Sung SA, Lee J, Oh KH, Kim SW, Kang SW, Choi KH, Ahn C, Han SH. Urinary chloride concentration and progression of chronic kidney disease: results from the KoreaN cohort study for Outcomes in patients With Chronic Kidney Disease. Nephrol Dial Transplant 2021; 36:673-680. [PMID: 31848615 DOI: 10.1093/ndt/gfz247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Urinary chloride is regulated by kidney transport channels, and high urinary chloride concentration in the distal tubules can trigger tubuloglomerular feedback. However, little attention has been paid to urinary chloride as a biomarker of clinical outcomes. Here, we studied the relationship between urinary chloride concentration and chronic kidney disease (CKD) progression. METHODS We included 2086 participants with CKD from the KoreaN cohort study for Outcomes in patients With Chronic Kidney Disease. Patients were categorized into three groups, according to baseline urinary chloride concentration tertiles. The study endpoint was a composite of ≥50% decrease in estimated glomerular filtration rate from baseline values, or end-stage kidney disease. RESULTS During a median follow-up period of 3.4 years (7452 person-years), 565 participants reached the primary endpoint. There was a higher rate of CKD progression events in the lowest and middle tertiles than in the highest tertile. Compared with the lowest tertile, the highest tertile was associated with 33% [95% confidence interval (CI) 0.49-0.90] lower risk for the primary outcome in a cause-specific hazard model after adjustment for confounding variables. In addition, for every 25 mEq/L increase in urinary chloride concentration, there was 11% (95% CI 0.83-0.96) lower risk for CKD progression. This association was consistent in a time-varying model. Urinary chloride concentration correlated well with tubule function and kidney injury markers, and its predictive performance for CKD progression was comparable to that of these markers. CONCLUSIONS In this hypothesis-generating study, low urinary chloride concentration was associated with a higher risk for CKD progression.
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Affiliation(s)
- Young Su Joo
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea.,Division of Nephrology, Department of Internal Medicine, Myongji Hospital, Goyang, Republic of Korea
| | - Jinseok Kim
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea
| | - Cheol Ho Park
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea
| | - Hae-Ryong Yun
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea
| | - Jung Tak Park
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea
| | - Tae Ik Chang
- Department of Internal Medicine, National Health Insurance Service Medical Center, Ilsan Hospital, Goyang, Republic of Korea
| | - Tae-Hyun Yoo
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea
| | - Su-Ah Sung
- Department of Internal Medicine, Eulji Medical Center, Eulji University, Seoul, Republic of Korea
| | - Joongyub Lee
- Department of Prevention and Management, Inha University School of Medicine, Incheon, Republic of Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Shin-Wook Kang
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea.,Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Republic of Korea
| | - Kyu Hun Choi
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea
| | - Curie Ahn
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Seung Hyeok Han
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Republic of Korea
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17
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Gyarmati G, Shroff UN, Riquier-Brison A, Kriz W, Kaissling B, Neal CR, Arkill KP, Ahmadi N, Gill IS, Moon JY, Desposito D, Peti-Peterdi J. A new view of macula densa cell microanatomy. Am J Physiol Renal Physiol 2021; 320:F492-F504. [PMID: 33491562 DOI: 10.1152/ajprenal.00546.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Although macula densa (MD) cells are chief regulatory cells in the nephron with unique microanatomical features, they have been difficult to study in full detail due to their inaccessibility and limitations in earlier microscopy techniques. The present study used a new mouse model with a comprehensive imaging approach to visualize so far unexplored microanatomical features of MD cells, their regulation, and functional relevance. MD-GFP mice with conditional and partial induction of green fluorescent protein (GFP) expression, which specifically and intensely illuminated only single MD cells, were used with fluorescence microscopy of fixed tissue and live MD cells in vitro and in vivo with complementary electron microscopy of the rat, rabbit, and human kidney. An elaborate network of major and minor cell processes, here named maculapodia, were found at the cell base, projecting toward other MD cells and the glomerular vascular pole. The extent of maculapodia showed upregulation by low dietary salt intake and the female sex. Time-lapse imaging of maculapodia revealed highly dynamic features including rapid outgrowth and an extensive vesicular transport system. Electron microscopy of rat, rabbit, and human kidneys and three-dimensional volume reconstruction in optically cleared whole-mount MD-GFP mouse kidneys further confirmed the presence and projections of maculapodia into the extraglomerular mesangium and afferent and efferent arterioles. The newly identified dynamic and secretory features of MD cells suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD cells and between MD and other target cells.NEW & NOTEWORTHY This study illuminated a physiologically regulated dense network of basal cell major and minor processes (maculapodia) in macula densa (MD) cells. The newly identified dynamic and secretory features of these microanatomical structures suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD and other target cells. Detailed characterization of the function and molecular details of MD cell intercellular communications and their role in physiology and disease warrant further studies.
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Affiliation(s)
- Georgina Gyarmati
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Urvi Nikhil Shroff
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Anne Riquier-Brison
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Wilhelm Kriz
- Centre for Biomedicine and Medical Technology Mannheim, Neuroanatomy, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - Christopher R Neal
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Kenton P Arkill
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham Biodiscovery Institute, University Park, United Kingdom
| | - Nariman Ahmadi
- Institute of Urology, Catherine & Joseph Aresty Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Inderbir S Gill
- Institute of Urology, Catherine & Joseph Aresty Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Ju-Young Moon
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Dorinne Desposito
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - János Peti-Peterdi
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
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18
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Yoshihisa A, Watanabe K, Sato Y, Ishibashi S, Matsuda M, Yamadera Y, Ichijo Y, Yokokawa T, Misaka T, Oikawa M, Kobayashi A, Takeishi Y. Intrarenal Doppler ultrasonography reflects hemodynamics and predicts prognosis in patients with heart failure. Sci Rep 2020; 10:22257. [PMID: 33335236 PMCID: PMC7746684 DOI: 10.1038/s41598-020-79351-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 12/08/2020] [Indexed: 12/24/2022] Open
Abstract
We aimed to clarify clinical implications of intrarenal hemodynamics assessed by intrarenal Doppler ultrasonography (IRD) and their prognostic impacts in heart failure (HF). We performed a prospective observational study, and examined IRD and measured interlobar renal artery velocity time integral (VTI) and intrarenal venous flow (IRVF) patterns (monophasic or non-monophasic pattern) to assess intrarenal hypoperfusion and congestion in HF patients (n = 341). Seven patients were excluded in VTI analysis due to unclear imaging. The patients were divided into groups based on (A) VTI: high VTI (VTI ≥ 14.0 cm, n = 231) or low VTI (VTI < 14.0 cm, n = 103); and (B) IRVF patterns: monophasic (n = 36) or non-monophasic (n = 305). We compared post-discharge cardiac event rate between the groups, and right-heart catheterization was performed in 166 patients. Cardiac index was lower in low VTI than in high VTI (P = 0.04), and right atrial pressure was higher in monophasic than in non-monophasic (P = 0.03). In the Kaplan–Meier analysis, cardiac event rate was higher in low VTI and monophasic groups (P < 0.01, respectively). In the Cox proportional hazard analysis, the combination of low VTI and a monophasic IRVF pattern was a predictor of cardiac events (P < 0.01). IRD imaging might be associated with cardiac output and right atrial pressure, and prognosis.
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Affiliation(s)
- Akiomi Yoshihisa
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan.
| | - Koichiro Watanabe
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
| | - Yu Sato
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
| | - Shinji Ishibashi
- Department of Clinical Laboratory Medicine, Fukushima Medical University, Fukushima, Japan
| | - Mitsuko Matsuda
- Department of Clinical Laboratory Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yukio Yamadera
- Department of Clinical Laboratory Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yasuhiro Ichijo
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
| | - Tetsuro Yokokawa
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
| | - Tomofumi Misaka
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
| | - Masayoshi Oikawa
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
| | - Atsushi Kobayashi
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
| | - Yasuchika Takeishi
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan
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19
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Shigemura N, Takai S, Hirose F, Yoshida R, Sanematsu K, Ninomiya Y. Expression of Renin-Angiotensin System Components in the Taste Organ of Mice. Nutrients 2019; 11:nu11092251. [PMID: 31546789 PMCID: PMC6770651 DOI: 10.3390/nu11092251] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/13/2019] [Accepted: 09/15/2019] [Indexed: 12/20/2022] Open
Abstract
The systemic renin-angiotensin system (RAS) is an important regulator of body fluid and sodium homeostasis. Angiotensin II (AngII) is a key active product of the RAS. We previously revealed that circulating AngII suppresses amiloride-sensitive salt taste responses and enhances the responses to sweet compounds via the AngII type 1 receptor (AT1) expressed in taste cells. However, the molecular mechanisms underlying the modulation of taste function by AngII remain uncharacterized. Here we examined the expression of three RAS components, namely renin, angiotensinogen, and angiotensin-converting enzyme-1 (ACE1), in mouse taste tissues. We found that all three RAS components were present in the taste buds of fungiform and circumvallate papillae and co-expressed with αENaC (epithelial sodium channel α-subunit, a salt taste receptor) or T1R3 (taste receptor type 1 member 3, a sweet taste receptor component). Water-deprived mice exhibited significantly increased levels of renin expression in taste cells (p < 0.05). These results indicate the existence of a local RAS in the taste organ and suggest that taste function may be regulated by both locally-produced and circulating AngII. Such integrated modulation of peripheral taste sensitivity by AngII may play an important role in sodium/calorie homeostasis.
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Affiliation(s)
- Noriatsu Shigemura
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
- Division of Sensory Physiology, Development Center for Five-Sense Devices, Kyushu University, Fukuoka 819-0395, Japan.
| | - Shingo Takai
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Fumie Hirose
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
- Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan.
| | - Ryusuke Yoshida
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan.
| | - Keisuke Sanematsu
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
- Division of Sensory Physiology, Development Center for Five-Sense Devices, Kyushu University, Fukuoka 819-0395, Japan.
| | - Yuzo Ninomiya
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
- Division of Sensory Physiology, Development Center for Five-Sense Devices, Kyushu University, Fukuoka 819-0395, Japan.
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA.
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20
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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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GRK2 knockdown in mice exacerbates kidney injury and alters renal mechanisms of blood pressure regulation. Sci Rep 2018; 8:11415. [PMID: 30061705 PMCID: PMC6065385 DOI: 10.1038/s41598-018-29876-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023] Open
Abstract
The renin-angiotensin system regulates blood pressure and fluid balance in the body primarily via angiotensin receptor 1 (AT1R). Renal AT1R was found to be primarily responsible for Ang II-mediated hypertension. G protein-coupled receptor kinase 2 (GRK2) modulates AT1R desensitization and increased GRK2 protein expression is reported in hypertensive patients. However, the consequences of GRK2 inhibition on kidney functions remain unknown. We employed shGRK2 knockdown mice (shGRK2 mice) to test the role of GRK2 in kidney development and function that can be ultimately linked to the hypertensive phenotype detected in shGRK2 mice. GRK2 knockdown reduced kidney size, nephrogenesis and glomerular count, and impaired glomerular filtration. Glomerular damage in adult shGRK2 mice was associated with increased renin- and AT1R-mediated production of reactive oxygen species. The AT1R blocker, Losartan, normalized elevated blood pressure and markedly improved glomerular filtration in the shGRK2 knockdown mice. Our findings provide evidence for the crucial role of GRK2 in renal regulation of blood pressure. It also suggests that the detrimental outcomes of GRK2 inhibitors on the kidney should be carefully examined when used as antihypertensive.
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22
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Takahama H, Kitakaze M. Pathophysiology of cardiorenal syndrome in patients with heart failure: potential therapeutic targets. Am J Physiol Heart Circ Physiol 2017; 313:H715-H721. [PMID: 28733448 DOI: 10.1152/ajpheart.00215.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/27/2017] [Accepted: 07/13/2017] [Indexed: 12/16/2022]
Abstract
Despite the development of pharmacological inventions and new nonpharmacological techniques to prevent and treat heart failure (HF), the mortality rate in patients with symptomatic HF remains high. To conquer these difficulties, the pathophysiology of HF should be considered within a wide range of views. Given the diverse mechanisms of HF pathophysiology, renal and cardiac functions have close and complementary interconnections. Recent studies have suggested that communication between the kidney and heart through bidirectional pathways causes significant pathological changes. This review summarizes the pathophysiology of cardiorenal syndrome (CRS) from three different viewpoints, namely, underlying chronic kidney disease, worsening renal function during hospitalization due to HF, and resistance to diuretics. We also summarize the presently available data on the pathophysiology of CRS, identify the challenges associated with some clinical approaches, and explore the potential therapeutic target for CRS.
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Affiliation(s)
- Hiroyuki Takahama
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan; and
| | - Masafumi Kitakaze
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan; and.,Department of Clinical Research and Development, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
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23
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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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24
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Venner JM, Famulski KS, Reeve J, Chang J, Halloran PF. Relationships among injury, fibrosis, and time in human kidney transplants. JCI Insight 2016; 1:e85323. [PMID: 27699214 DOI: 10.1172/jci.insight.85323] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Kidney transplant biopsies offer an opportunity to understand the pathogenesis of organ fibrosis. We studied the relationships between the time of biopsy after transplant (TxBx), histologic fibrosis, diseases, and transcript expression. METHODS Expression microarrays from 681 kidney transplant indication biopsies taken either early (n = 282, <1 year) or late (n = 399, >1 year) after transplant were used to analyze the molecular landscape of fibrosis in relationship to histologic fibrosis and diseases. RESULTS Fibrosis was absent at transplantation but was present in some early biopsies by 4 months after transplant, apparently as a self-limited response to donation implantation injury not associated with progression to failure. The molecular phenotype of early biopsies represented the time sequence of the response to wounding: immediate expression of acute kidney injury transcripts, followed by fibrillar collagen transcripts after several weeks, then by the appearance of immunoglobulin and mast cell transcripts after several months as fibrosis appeared. Fibrosis in late biopsies correlated with injury, fibrillar collagen, immunoglobulin, and mast cell transcripts, but these were independent of time. Pathway analysis revealed epithelial response-to-wounding pathways such as Wnt/β-catenin. CONCLUSION Fibrosis in late biopsies had different associations because many kidneys had potentially progressive diseases and subsequently failed. Molecular correlations with fibrosis in late biopsies were independent of time, probably because ongoing injury obscured the response-to-wounding time sequence. The results indicate that fibrosis in kidney transplants is driven by nephron injury and that progression to failure reflects continuing injury, not autonomous fibrogenesis. TRIAL REGISTRATION INTERCOM study (www.clinicalTrials.gov; NCT01299168). FUNDING Canada Foundation for Innovation and Genome Canada.
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Affiliation(s)
- Jeffery M Venner
- Alberta Transplant Applied Genomics Centre, Edmonton, Alberta, Canada.,Department of Medicine, Division of Nephrology and Transplant Immunology, Edmonton, Alberta, Canada
| | - Konrad S Famulski
- Alberta Transplant Applied Genomics Centre, Edmonton, Alberta, Canada.,Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Jeff Reeve
- Alberta Transplant Applied Genomics Centre, Edmonton, Alberta, Canada.,Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Jessica Chang
- Alberta Transplant Applied Genomics Centre, Edmonton, Alberta, Canada
| | - Philip F Halloran
- Alberta Transplant Applied Genomics Centre, Edmonton, Alberta, Canada.,Department of Medicine, Division of Nephrology and Transplant Immunology, Edmonton, Alberta, Canada
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Sabirov RZ, Merzlyak PG, Islam MR, Okada T, Okada Y. The properties, functions, and pathophysiology of maxi-anion channels. Pflugers Arch 2016; 468:405-20. [DOI: 10.1007/s00424-015-1774-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 01/19/2023]
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Wang L, Shen C, Liu H, Wang S, Chen X, Roman RJ, Juncos LA, Lu Y, Wei J, Zhang J, Yip KP, Liu R. Shear stress blunts tubuloglomerular feedback partially mediated by primary cilia and nitric oxide at the macula densa. Am J Physiol Regul Integr Comp Physiol 2015; 309:R757-66. [PMID: 26269519 PMCID: PMC4666931 DOI: 10.1152/ajpregu.00173.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 08/05/2015] [Indexed: 02/04/2023]
Abstract
The present study tested whether primary cilia on macula densa serve as a flow sensor to enhance nitric oxide synthase 1 (NOS1) activity and inhibit tubuloglomerular feedback (TGF). Isolated perfused macula densa was loaded with calcein red and 4,5-diaminofluorescein diacetate to monitor cell volume and nitric oxide (NO) generation. An increase in tubular flow rate from 0 to 40 nl/min enhanced NO production by 40.0 ± 1.2%. The flow-induced NO generation was blocked by an inhibitor of NOS1 but not by inhibition of the Na/K/2Cl cotransporter or the removal of electrolytes from the perfusate. NO generation increased from 174.8 ± 21 to 276.1 ± 24 units/min in cultured MMDD1 cells when shear stress was increased from 0.5 to 5.0 dynes/cm(2). The shear stress-induced NO generation was abolished in MMDD1 cells in which the cilia were disrupted using a siRNA to ift88. Increasing the NaCl concentration of the tubular perfusate from 10 to 80 mM NaCl in the isolated perfused juxtaglomerular preparation reduced the diameter of the afferent arteriole by 3.8 ± 0.1 μm. This response was significantly blunted to 2.5 ± 0.2 μm when dextran was added to the perfusate to increase the viscosity and shear stress. Inhibition of NOS1 blocked the effect of dextran on TGF response. In vitro, the effects of raising perfusate viscosity with dextran on tubular hydraulic pressure were minimized by reducing the outflow resistance to avoid stretching of tubular cells. These results suggest that shear stress stimulates primary cilia on the macula densa to enhance NO generation and inhibit TGF responsiveness.
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Affiliation(s)
- Lei Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Chunyu Shen
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; Department of Forensic Pathology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; and
| | - Haifeng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Shaohui Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Xinshan Chen
- Department of Forensic Pathology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; and
| | - Richard J Roman
- Department of Physiology/Pharmacology, University of Mississippi Medical Center, Jackson Mississippi
| | - Luis A Juncos
- Department of Physiology/Pharmacology, University of Mississippi Medical Center, Jackson Mississippi
| | - Yan Lu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; Department of Physiology/Pharmacology, University of Mississippi Medical Center, Jackson Mississippi
| | - Jin Wei
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Jie Zhang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Kay-Pong Yip
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida;
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Nadal-Quirós M, Moore LC, Marcano M. Parameter estimation for mathematical models of a nongastric H+(Na+)-K(+)(NH4+)-ATPase. Am J Physiol Renal Physiol 2015; 309:F434-46. [PMID: 26109090 PMCID: PMC4556890 DOI: 10.1152/ajprenal.00539.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 06/18/2015] [Indexed: 11/22/2022] Open
Abstract
The role of nongastric H(+)-K(+)-ATPase (HKA) in ion homeostasis of macula densa (MD) cells is an open question. To begin to explore this issue, we developed two mathematical models that describe ion fluxes through a nongastric HKA. One model assumes a 1H(+):1K(+)-per-ATP stoichiometry; the other assumes a 2H(+):2K(+)-per-ATP stoichiometry. Both models include Na+ and NH4+ competitive binding with H+ and K+, respectively, a characteristic observed in vitro and in situ. Model rate constants were obtained by minimizing the distance between model and experimental outcomes. Both 1H(+)(1Na(+)):1K(+)(1NH4 (+))-per-ATP and 2H(+)(2Na(+)):2K(+)(2NH4 (+))-per-ATP models fit the experimental data well. Using both models, we simulated ion net fluxes as a function of cytosolic or luminal ion concentrations typical for the cortical thick ascending limb and MD region. We observed that (1) K+ and NH4+ flowed in the lumen-to-cytosol direction, (2) there was competitive behavior between luminal K+ and NH4+ and between cytosolic Na+ and H+, 3) ion fluxes were highly sensitive to changes in cytosolic Na+ or H+ concentrations, and 4) the transporter does mostly Na+ / K+ exchange under physiological conditions. These results support the concept that nongastric HKA may contribute to Na+ and pH homeostasis in MD cells. Furthermore, in both models, H+ flux reversed at a luminal pH that was <5.6. Such reversal led to Na+ / H+ exchange for a luminal pH of <2 and 4 in the 1:1-per-ATP and 2:2-per-ATP models, respectively. This suggests a novel role of nongastric HKA in cell Na+ homeostasis in the more acidic regions of the renal tubules.
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Affiliation(s)
| | - Leon C Moore
- Department of Physiology and Biophysics, State University of New York Health Science Center, Stony Brook, New York
| | - Mariano Marcano
- Department of Computer Science, University of Puerto Rico, Río Piedras, Puerto Rico
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Burke M, Pabbidi MR, Farley J, Roman RJ. Molecular mechanisms of renal blood flow autoregulation. Curr Vasc Pharmacol 2015; 12:845-58. [PMID: 24066938 PMCID: PMC4416696 DOI: 10.2174/15701611113116660149] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 12/18/2011] [Accepted: 07/02/2013] [Indexed: 01/10/2023]
Abstract
Diabetes and hypertension are the leading causes of chronic kidney disease and their incidence is increasing at
an alarming rate. Both are associated with impairments in the autoregulation of renal blood flow (RBF) and greater transmission
of fluctuations in arterial pressure to the glomerular capillaries. The ability of the kidney to maintain relatively
constant blood flow, glomerular filtration rate (GFR) and glomerular capillary pressure is mediated by the myogenic response
of afferent arterioles working in concert with tubuloglomerular feedback that adjusts the tone of the afferent arteriole
in response to changes in the delivery of sodium chloride to the macula densa. Despite intensive investigation, the factors
initiating the myogenic response and the signaling pathways involved in the myogenic response and tubuloglomerular
feedback remain uncertain. This review focuses on current thought regarding the molecular mechanisms underlying myogenic
control of renal vascular tone, the interrelationships between the myogenic response and tubuloglomerular feedback,
the evidence that alterations in autoregulation of RBF contributes to hypertension and diabetes-induced nephropathy and
the identification of vascular therapeutic targets for improved renoprotection in hypertensive and diabetic patients.
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Affiliation(s)
| | | | | | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
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Guan Z, Fellner RC, Van Beusecum J, Inscho EW. P2 receptors in renal autoregulation. Curr Vasc Pharmacol 2015; 12:818-28. [PMID: 24066935 DOI: 10.2174/15701611113116660152] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 03/06/2013] [Accepted: 05/01/2014] [Indexed: 11/22/2022]
Abstract
Autoregulation of renal blood flow and glomerular filtration rate is an essential function of the renal microcirculation. While the existence of this phenomenon has been known for many years, the exact mechanisms that underlie this regulatory system remain poorly understood. The work of many investigators has provided insights into many aspects of the autoregulatory mechanism, but many critical components remain elusive. This review is intended to update the reader on the role of P2 purinoceptors as a postulated mechanism responsible for renal autoregulatory resistance adjustments. It will summarize recent advances in normal function and it will touch on more recent ideas regarding autoregulatory insufficiency in hypertension and inflammation. Current thoughts on the nature of the mechanosensor responsible for myogenic behavior will be also be discussed as well as current thoughts on the mechanisms involved in ATP release to the extracellular fluid space.
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Affiliation(s)
| | | | | | - Edward W Inscho
- Department of Physiology, Medical College of Georgia, Georgia Regents University, 1120 15th Street, Augusta, Georgia 30912-3000.
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Abed AB, Kavvadas P, Chadjichristos CE. Functional roles of connexins and pannexins in the kidney. Cell Mol Life Sci 2015; 72:2869-77. [PMID: 26082183 PMCID: PMC11113829 DOI: 10.1007/s00018-015-1964-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 12/22/2022]
Abstract
Kidneys are highly complex organs, playing a crucial role in human physiopathology, as they are implicated in vital processes, such as fluid filtration and vasomotor tone regulation. There is growing evidence that gap junctions are major determinants of renal physiopathology. It has been demonstrated that their expression or channel activity may vary depending on physiological and pathological situations within distinct renal compartments. While some studies have focused on the role of connexins in renal physiology, our knowledge regarding the functional relevance of pannexins is still very limited. In this paper, we provide an overview of the involvement of connexins, pannexins and their channels in various physiological processes related to different renal compartments.
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Affiliation(s)
- Ahmed B. Abed
- INSERM UMR-S1155, Batiment Recherche, Tenon Hospital, 4 rue de la Chine, 75020 Paris, France
- Sorbonne Universite´s, UPMC Univ Paris 6, Paris, France
| | - Panagiotis Kavvadas
- INSERM UMR-S1155, Batiment Recherche, Tenon Hospital, 4 rue de la Chine, 75020 Paris, France
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Orlov SN, Koltsova SV, Kapilevich LV, Gusakova SV, Dulin NO. NKCC1 and NKCC2: The pathogenetic role of cation-chloride cotransporters in hypertension. Genes Dis 2015; 2:186-196. [PMID: 26114157 PMCID: PMC4477834 DOI: 10.1016/j.gendis.2015.02.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/16/2015] [Indexed: 11/17/2022] Open
Abstract
This review summarizes the data on the functional significance of ubiquitous (NKCC1) and renal-specific (NKCC2) isoforms of electroneutral sodium, potassium and chloride cotransporters. These carriers contribute to the pathogenesis of hypertension via regulation of intracellular chloride concentration in vascular smooth muscle and neuronal cells and via sensing chloride concentration in the renal tubular fluid, respectively. Both NKCC1 and NKCC2 are inhibited by furosemide and other high-ceiling diuretics widely used for attenuation of extracellular fluid volume. However, the chronic usage of these compounds for the treatment of hypertension and other volume-expanded disorders may have diverse side-effects due to suppression of myogenic response in microcirculatory beds.
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Affiliation(s)
- Sergei N. Orlov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Russia
- Тomsk State University, Russia
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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Weinstein AM. A mathematical model of rat proximal tubule and loop of Henle. Am J Physiol Renal Physiol 2015; 308:F1076-97. [PMID: 25694479 DOI: 10.1152/ajprenal.00504.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 02/10/2015] [Indexed: 01/11/2023] Open
Abstract
Proximal tubule and loop of Henle function are coupled, with proximal transport determining loop fluid composition, and loop transport modulating glomerular filtration via tubuloglomerular feedback (TGF). To examine this interaction, we begin with published models of the superficial rat proximal convoluted tubule (PCT; including flow-dependent transport in a compliant tubule), and the rat thick ascending Henle limb (AHL). Transport parameters for this PCT are scaled down to represent the proximal straight tubule (PST), which is connected to the thick AHL via a short descending limb. Transport parameters for superficial PCT and PST are scaled up for a juxtamedullary nephron, and connected to AHL via outer and inner medullary descending limbs, and inner medullary thin AHL. Medullary interstitial solute concentrations are specified. End-AHL hydrostatic pressure is determined by distal nephron flow resistance, and the TGF signal is represented as a linear function of end-AHL cytosolic Cl concentration. These two distal conditions required iterative solution of the model. Model calculations capture inner medullary countercurrent flux of urea, and also suggest the presence of an outer medullary countercurrent flux of ammonia, with reabsorption in AHL and secretion in PST. For a realistically strong TGF signal, there is the expected homeostatic impact on distal flows, and in addition, a homeostatic effect on proximal tubule pressure. The model glycosuria threshold is compatible with rat data, and predicted glucose excretion with selective 1Na(+):1glucose cotransporter (SGLT2) inhibition comports with observations in the mouse. Model calculations suggest that enhanced proximal tubule Na(+) reabsorption during hyperglycemia is sufficient to activate TGF and contribute to diabetic hyperfiltration.
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Affiliation(s)
- Alan M Weinstein
- Department of Physiology and Biophysics, Department of Medicine, Weill Medical College of Cornell University, New York, New York
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Edwards A, Castrop H, Laghmani K, Vallon V, Layton AT. Effects of NKCC2 isoform regulation on NaCl transport in thick ascending limb and macula densa: a modeling study. Am J Physiol Renal Physiol 2014; 307:F137-46. [PMID: 24848496 DOI: 10.1152/ajprenal.00158.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study aims to understand the extent to which modulation of the Na(+)-K(+)-2Cl(-) cotransporter NKCC2 differential splicing affects NaCl delivery to the macula densa. NaCl absorption by the thick ascending limb and macula densa cells is mediated by apical NKCC2. A recent study has indicated that differential splicing of NKCC2 is modulated by dietary salt (Schieβl IM, Rosenauer A, Kattler V, Minuth WW, Oppermann M, Castrop H. Am J Physiol Renal Physiol 305: F1139-F1148, 2013). Given the markedly different ion affinities of its splice variants, modulation of NKCC2 differential splicing is believed to impact NaCl reabsorption. To assess the validity of that hypothesis, we have developed a mathematical model of macula densa cell transport and incorporated that cell model into a previously applied model of the thick ascending limb (Weinstein AM, Krahn TA. Am J Physiol Renal Physiol 298: F525-F542, 2010). The macula densa model predicts a 27.4- and 13.1-mV depolarization of the basolateral membrane [as a surrogate for activation of tubuloglomerular feedback (TGF)] when luminal NaCl concentration is increased from 25 to 145 mM or luminal K(+) concentration is increased from 1.5 to 3.5 mM, respectively, consistent with experimental measurements. Simulations indicate that with luminal solute concentrations consistent with in vivo conditions near the macula densa, NKCC2 operates near its equilibrium state. Results also suggest that modulation of NKCC2 differential splicing by low salt, which induces a shift from NKCC2-A to NKCC2-B primarily in the cortical thick ascending limb and macula densa cells, significantly enhances salt reabsorption in the thick limb and reduces Na(+) and Cl(-) delivery to the macula densa by 3.7 and 12.5%, respectively. Simulation results also predict that the NKCC2 isoform shift hyperpolarizes the macula densa basolateral cell membrane, which, taken in isolation, may inhibit the release of the TGF signal. However, excessive early distal salt delivery and renal salt loss during a low-salt diet may be prevented by an asymmetric TGF response, which may be more sensitive to flow increases.
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Affiliation(s)
- Aurélie Edwards
- University of Paris 6, University of Paris 5, Institut National de la Santé et de la Recherche Médicale UMRS 1138, Centre National de la Recherche Scientifique ERL 8228, Centre de Recherche des Cordeliers, Paris, France
| | - Hayo Castrop
- Institute of Physiology University of Regensburg, Regensburg, Germany
| | - Kamel Laghmani
- University of Paris 6, University of Paris 5, Institut National de la Santé et de la Recherche Médicale UMRS 1138, Centre National de la Recherche Scientifique ERL 8228, Centre de Recherche des Cordeliers, Paris, France
| | - Volker Vallon
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California, and San Diego Veterans Affairs Healthcare System, San Diego, California; and
| | - Anita T Layton
- Department of Mathematics, Duke University, Durham, North Carolina
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Ahmeda AF, Rae MG, Johns EJ. Effect of reactive oxygen species and nitric oxide in the neural control of intrarenal haemodynamics in anaesthetized normotensive rats. Acta Physiol (Oxf) 2013; 209:156-66. [PMID: 23910436 DOI: 10.1111/apha.12150] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/15/2013] [Accepted: 07/24/2013] [Indexed: 12/13/2022]
Abstract
AIMS This study examined the interaction between reactive oxygen species and nitric oxide (NO) in mediating the decrease in renal blood flow (RBF) evoked by sympathetic renal nerve stimulation (RNS). METHODS Groups of male Wistar rats were subjected to RNS at different frequencies prior to, and following, an infusion of: (i) tempol, the superoxide dismutase (SOD) mimetic, (ii) tempol plus the hydrogen peroxide-degrading enzyme catalase (tem + cat), (iii) diethyldithiocarbamic acid (DETC), a SOD inhibitor, (iv) the nitric oxide synthase (NOS) inhibitor, L-nitro-arginine methyl ester (L-NAME) alone, or (v) L-NAME followed by tempol, into the kidney cortico-medullary border (CMB). Blood perfusion within the cortical (CBP) and medullary (MBP) regions of the kidney was measured using Laser-Doppler flowmetry. RESULTS Infusion of tempol CMB significantly attenuated RNS-evoked reductions in CBP (by 22% at 8 Hz; P < 0.05), but not MBP. When tempol and catalase were co-infused to reduce both ROS and hydrogen peroxide (H2 O2 ), respectively, there was a significantly greater attenuation of the RNS-evoked reduction in CBP compared with that of tempol alone. Infusion of either DETC or L-NAME alone did not significantly affect the CBP or MBP responses to RNS. Similarly, RNS following tempol infusion with L-NAME also had no effect on CBP and MBP over and above the group that received tempol alone. CONCLUSION These results suggest that reactive oxygen species such as superoxide and H2 O2 have a direct role in reducing renal vascular compliance in response to RNS, rather than indirectly through scavenging NO.
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Affiliation(s)
- A. F. Ahmeda
- Department of Physiology; University College Cork; Cork; Ireland
| | - M. G. Rae
- Department of Physiology; University College Cork; Cork; Ireland
| | - E. J. Johns
- Department of Physiology; University College Cork; Cork; Ireland
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Ren Y, D'Ambrosio MA, Garvin JL, Wang H, Carretero OA. Mechanism of inhibition of tubuloglomerular feedback by CO and cGMP. Hypertension 2013; 62:99-104. [PMID: 23648700 DOI: 10.1161/hypertensionaha.113.01164] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Tubuloglomerular feedback (TGF) is a mechanism that senses NaCl in the macula densa (MD) and causes constriction of the afferent arteriole. CO, either endogenous or exogenous, inhibits TGF at least in part via cGMP. We hypothesize that CO in the MD, acting via both cGMP-dependent and -independent mechanisms, attenuates TGF by acting downstream from depolarization and calcium entry into the MD cells. In vitro, microdissected rabbit afferent arterioles and their MD were simultaneously perfused and TGF was measured as the decrease in afferent arteriole diameter. MD depolarization was induced with ionophores, while adding the CO-releasing molecule-3 to the MD perfusate at nontoxic concentrations. CO-releasing molecule-3 blunted depolarization-induced TGF at 50 μmol/L, from 3.6±0.4 to 2.5±0.4 µm (P<0.01), and abolished it at 100 μmol/L, to 0.1±0.1 μm (P<0.001; n=6). When cGMP generation was blocked by guanylyl cyclase inhibitor LY83583 added to the MD, CO-releasing molecule-3 no longer affected depolarization-induced TGF at 50 μmol/L (2.9±0.4 versus 3.0±0.4 µm) but partially inhibited TGF at 100 μmol/L (to 1.3±0.2 μm; P<0.05; n=9). Experiments using eicosatetraynoic acid and indomethacin suggest arachidonic acid metabolites do not mediate the cGMP-independent effect of CO. We then added the calcium ionophore A23187 to the MD, which caused TGF (4.1±0.6 μmol/L); A23187-induced TGF was inhibited by CO-releasing molecule-3 at 50 μmol/L (1.9±0.6 μmol/L; P<0.01) and 100 μmol/L (0.2±0.5 μmol/L; P<0.001; n=6). We conclude that CO inhibits TGF acting downstream from depolarization and calcium entry, acting via cGMP at low concentrations, but additional mechanisms of action may be involved at higher concentrations.
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Affiliation(s)
- Yilin Ren
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, MI 48202, USA
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Asakura J, Hasegawa H, Takayanagi K, Shimazu T, Suge R, Shimizu T, Iwashita T, Tayama Y, Matsuda A, Kanozawa K, Araki N, Mitarai T. Renoprotective effect of pioglitazone by the prevention of glomerular hyperfiltration through the possible restoration of altered macula densa signaling in rats with type 2 diabetic nephropathy. Nephron Clin Pract 2013; 122:83-94. [PMID: 23548923 DOI: 10.1159/000348661] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 02/03/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND/AIMS Pioglitazone (PGZ), one of the thiazolidinediones, has been known to show renoprotective effects. In this study, we focused on the effect of PGZ on glomerular hyperfiltration (GHF), resultant glomerular injury and altered macula densa signaling as a cause of sustained GHF through modified tubuloglomerular feedback in rats with diabetic nephropathy. METHODS Kidneys from 24-week-old male OLETF rats and LET rats, nondiabetic controls, were used for the experiment. PGZ was administered (10 mg/kg/day, p.o.) for 2 weeks from 22 to 24 weeks of age in some of the OLETF rats (OLETF+PGZ). RESULTS Parameters relating GHF, kidney weight, creatinine clearance, urine albumin/creatinine ratio and glomerular surface were all increased in OLETF rats and partially restored in OLETF+PGZ rats. Expressions of desmin and TGF-β were also increased in OLETF rats and restored in OLETF+PGZ rats. The changes in TGF-β expression were confirmed to be independent of podocyte number. Finally, the immunoreactivity of neuronal nitric oxide synthase (nNOS) and cyclooxygenase 2 (COX-2) in the macula densa was assessed for the evaluation of macula densa signaling. Altered intensities of nNOS and COX-2 in OLETF rats were restored in OLETF+PGZ rats, which agreed with the gene expression analysis (nNOS: 100.2 ± 2.9% in LET, 64.2 ± 2.7% in OLETF, 87.4 ± 12.1% in OLETF+PGZ; COX-2: 100.8 ± 7.4% in LET, 249.2 ± 19.4% in OLETF, 179.9 ± 13.5% in OLETF+PGZ; n = 5) and the semiquantitative analysis of nNOS/COX-2-positive cells. CONCLUSION PGZ effectively attenuated the GHF and hyperfiltration-associated glomerular injury in diabetic nephropathy. The restoration of altered macula densa signaling might be involved in the renoprotective effect of PGZ.
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Affiliation(s)
- Juko Asakura
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
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Purinoceptor signaling in malaria-infected erythrocytes. Microbes Infect 2012; 14:779-86. [PMID: 22580091 DOI: 10.1016/j.micinf.2012.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Revised: 04/13/2012] [Accepted: 04/13/2012] [Indexed: 01/25/2023]
Abstract
Human erythrocytes are endowed with ATP release pathways and metabotropic and ionotropic purinoceptors. This review summarizes the pivotal function of purinergic signaling in erythrocyte control of vascular tone, in hemolytic septicemia, and in malaria. In malaria, the intraerythrocytic parasite exploits the purinergic signaling of its host to adapt the erythrocyte to its requirements.
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Effect of low sodium intake and β-blockade on renin synthesis and secretion in mice with unilateral ureteral ligation. Hypertens Res 2010; 33:1258-63. [PMID: 20882029 DOI: 10.1038/hr.2010.167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We previously reported that sodium depletion increased renin secretion from the normal kidney in mice. We postulated that the combined procedures of sodium depletion and β-adrenoceptor blockade would affect the activity of the renin-angiotensin system. To test this hypothesis, we investigated the interaction of low sodium intake (LSI) and propranolol (PRO) on renin synthesis and secretion. To prevent the influence of tubule flow on renin secretion, mice with a left hydronephrotic kidney were used. LSI increased plasma renin concentration (PRC) 5.6-fold in the right renal vein (P<0.01). There was no net increase of PRC in the left renal vein. Tissue renin concentration (TRC) was elevated 3.6-fold and 1.3-fold in the right and left kidneys (P<0.01), respectively. After administration of PRO, PRC decreased by 34% in the right renal vein and 47% in the aorta (P<0.05); TRC was reduced by 37.5% in the right and 29.3% in the hydronephrotic kidneys (P<0.05). The combination of LSI and PRO increased PRC 3.4-fold and 1.8-fold in the right (P<0.01) and left renal veins (P<0.05), respectively. TRC increased 3.4-fold in the right (P<0.01) but only 61% in the left kidneys (P<0.05). The pattern in change of renin mRNA levels was similar to TRC but the absolute amount was smaller. There were correlations between PRC and renin mRNA, and between TRC and renin mRNA in both kidneys (P<0.001). Thus, LSI increased renin synthesis in both kidneys. However, there was no apparent renin secretion in the hydronephrotic kidney. PRO treatment suppressed renin synthesis and renin secretion, irrespective of hydronephrosis and LSI. The macula densa is critical for renin secretion under all of the circumstances studied.
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NKCC1 and hypertension: a novel therapeutic target involved in the regulation of vascular tone and renal function. Curr Opin Nephrol Hypertens 2010; 19:163-8. [PMID: 20061948 DOI: 10.1097/mnh.0b013e3283360a46] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE OF REVIEW The present review summarizes recent advances in our understanding of the mechanisms involving the housekeeping Na+, K+, 2Cl(-) cotransporter (NKCC1) in blood pressure (BP) regulation. RECENT FINDINGS High-ceiling diuretics (HCDs), known potent inhibitors of NKCC1, renal-specific NKCC2 and four isoforms of K+, Cl(-) cotransporters decrease [Cl(-)]i, hyperpolarize vascular smooth muscle cells and suppress myogenic tone and contractions evoked by modest depolarization, phenylephrine, angiotensin II and uridine triphosphate. These actions are absent in NKCC1(-/-) mice, indicating that HCDs interact with NKCC1 rather than with other potential targets. NKCC1-null mice have decreased baseline BP but exhibit augmented BP increment evoked by high-salt diets. NKCC1 deficiency causes approximately three-fold elevation in plasma renin concentrations and attenuates HCD-induced renin production. In addition to HCDs, NKCC1 is also inhibited by extracellular HCO3(-) in the range corresponding to its concentration in ischemic extracellular fluids. SUMMARY NKCC1 modulates BP through vascular and renal effects. In addition to BP regulation, the decreased baseline activity of this carrier or its suppression by chronic treatment with HCDs may lead to inhibition of myogenic tone and progression of end-stage renal disease. NKCC1 activation in ischemia-induced acidosis may contribute to stroke via glutamate release caused by astrocyte swelling.
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Peti-Peterdi J, Harris RC. Macula densa sensing and signaling mechanisms of renin release. J Am Soc Nephrol 2010; 21:1093-6. [PMID: 20360309 DOI: 10.1681/asn.2009070759] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that generate paracrine chemical signals in the juxtaglomerular apparatus to control vital kidney functions, including renal blood flow, glomerular filtration, and renin release. Renin is the rate-limiting step in the activation of the renin-angiotensin system, a key modulator of body fluid homeostasis. Here, we discuss recent advances in understanding macula densa sensing and suggest these cells, in addition to salt, also sense various chemical and metabolic signals in the tubular environment that directly trigger renin release.
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Affiliation(s)
- János Peti-Peterdi
- Departments of Physiology and Biophysics and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA.
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Osmond DA, Inscho EW. P2X(1) receptor blockade inhibits whole kidney autoregulation of renal blood flow in vivo. Am J Physiol Renal Physiol 2010; 298:F1360-8. [PMID: 20335318 DOI: 10.1152/ajprenal.00016.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In vitro experiments demonstrate that P2X(1) receptor activation is important for normal afferent arteriolar autoregulatory behavior, but direct in vivo evidence for this relationship occurring in the whole kidney is unavailable. Experiments were performed to test the hypothesis that P2X(1) receptors are important for autoregulation of whole kidney blood flow. Renal blood flow (RBF) was measured in anesthetized male Sprague-Dawley rats before and during P2 receptor blockade with PPADS, P2X(1) receptor blockade with IP5I, or A(1) receptor blockade with DPCPX. Both P2X(1) and A(1) receptor stimulation with alpha,beta-methylene ATP and CPA, respectively, caused dose-dependent decreases in RBF. Administration of either PPADS or IP5I significantly blocked P2X(1) receptor stimulation. Likewise, administration of DPCPX significantly blocked A(1) receptor activation to CPA. Autoregulatory behavior was assessed by measuring RBF responses to reductions in renal perfusion pressure. In vehicle-infused rats, as pressure was decreased from 120 to 100 mmHg, there was no decrease in RBF. However, in either PPADS- or IP5I-infused rats, each decrease in pressure resulted in a significant decrease in RBF, demonstrating loss of autoregulatory ability. In DPCPX-infused rats, reductions in pressure did not cause significant reductions in RBF over the pressure range of 100-120 mmHg, but the autoregulatory curve tended to be steeper than vehicle-infused rats over the range of 80-100 mmHg, suggesting that A(1) receptors may influence RBF at lower pressures. These findings are consistent with in vitro data from afferent arterioles and support the hypothesis that P2X(1) receptor activation is important for whole kidney autoregulation in vivo.
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Affiliation(s)
- David A Osmond
- Department of Physiology, Medical College of Georgia, Augusta, Georgia 30912, USA
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Tanaka M, Asada M, Higashi AY, Nakamura J, Oguchi A, Tomita M, Yamada S, Asada N, Takase M, Okuda T, Kawachi H, Economides AN, Robertson E, Takahashi S, Sakurai T, Goldschmeding R, Muso E, Fukatsu A, Kita T, Yanagita M. Loss of the BMP antagonist USAG-1 ameliorates disease in a mouse model of the progressive hereditary kidney disease Alport syndrome. J Clin Invest 2010; 120:768-77. [PMID: 20197625 DOI: 10.1172/jci39569] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The glomerular basement membrane (GBM) is a key component of the filtering unit in the kidney. Mutations involving any of the collagen IV genes (COL4A3, COL4A4, and COL4A5) affect GBM assembly and cause Alport syndrome, a progressive hereditary kidney disease with no definitive therapy. Previously, we have demonstrated that the bone morphogenetic protein (BMP) antagonist uterine sensitization-associated gene-1 (USAG-1) negatively regulates the renoprotective action of BMP-7 in a mouse model of tubular injury during acute renal failure. Here, we investigated the role of USAG-1 in renal function in Col4a3-/- mice, which model Alport syndrome. Ablation of Usag1 in Col4a3-/- mice led to substantial attenuation of disease progression, normalization of GBM ultrastructure, preservation of renal function, and extension of life span. Immunohistochemical analysis revealed that USAG-1 and BMP-7 colocalized in the macula densa in the distal tubules, lying in direct contact with glomerular mesangial cells. Furthermore, in cultured mesangial cells, BMP-7 attenuated and USAG-1 enhanced the expression of MMP-12, a protease that may contribute to GBM degradation. These data suggest that the pathogenetic role of USAG-1 in Col4a3-/- mice might involve crosstalk between kidney tubules and the glomerulus and that inhibition of USAG-1 may be a promising therapeutic approach for the treatment of Alport syndrome.
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Affiliation(s)
- Mari Tanaka
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Liu R, Juncos LA. GTPase-Rac enhances depolarization-induced superoxide production by the macula densa during tubuloglomerular feedback. Am J Physiol Regul Integr Comp Physiol 2010; 298:R453-8. [PMID: 20007513 PMCID: PMC2828178 DOI: 10.1152/ajpregu.00622.2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 12/09/2009] [Indexed: 11/22/2022]
Abstract
Superoxide (O(2)(-) ) enhances tubuloglomerular feedback (TGF) by scavenging nitric oxide at the macula densa (MD). The primary source of O(2)(-) in the MD during TGF is NADPH oxidase, which is activated by membrane depolarization. While Rac, a small GTP-binding protein, has been shown to enhance NADPH oxidase activity, its role in O(2)(-) generation by the MD is unknown. We hypothesized that depolarization of the MD leads to translocation of Rac to the apical membrane, and its activation, in turn, augments O(2)(-) generation during TGF. We tested this by measuring membrane potential and increased O(2)(-) levels during TGF responses in isolated, perfused tubules containing the intact MD plaque. Switching tubular NaCl from 10 to 80 mM, which induces TGF, depolarized membrane potential by 28.4 + or - 4.5% from control (P < 0.05) and O(2)(-) levels from 124 + or - 19 to 361 + or - 27 U/min. This NaCl-induced depolarization and O(2)(-) generation were blocked by a Cl(-) channel blocker, 5-nitro-2(3-phenylpropylamino) benzoic acid (NPPB; 10(-6) M). Inhibition of Rac blunted NaCl-induced O(2)(-) generation by 47%. When the NaCl content of the MD perfusate was increased from 10 to 80 mM, immunointensity of Rac on the apical side increased from 32 + or - 3.1 to 46 + or - 2.5% of the total immunofluorescence in the MD, indicating that high NaCl induces the translocation of Rac to the apical membrane. This NaCl-induced Rac translocation was blocked by a Cl(-) channel blocker, NPPB, indicating that depolarization of the MD induced Rac translocation. In conclusion, we found that depolarization of the MD during TGF leads to translocation of Rac to the apical membrane, which enhances O(2)(-) generation by the MD.
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Affiliation(s)
- Ruisheng Liu
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 N. State St., Jackson MS 39216, USA.
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Casellas D. Methods for imaging Renin-synthesizing, -storing, and -secreting cells. Int J Hypertens 2009; 2010:298747. [PMID: 20948562 PMCID: PMC2949082 DOI: 10.4061/2010/298747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/07/2009] [Accepted: 09/08/2009] [Indexed: 12/04/2022] Open
Abstract
Renin-producing cells have been the object of intense research efforts for the past fifty years within the field of hypertension. Two decades ago, research focused on the concept and characterization of the intrarenal renin-angiotensin system. Early morphological studies led to the concept of the juxtaglomerular apparatus, a minute organ that links tubulovascular structures and function at the single nephron level. The kidney, thus, appears as a highly "topological organ" in which anatomy and function are intimately linked. This point is reflected by a concurrent and constant development of functional and structural approaches. After summarizing our current knowledge about renin cells and their distribution along the renal vascular tree, particularly along glomerular afferent arterioles, we reviewed a variety of imaging techniques that permit a fine characterization of renin synthesis, storage, and release at the single-arteriolar, -cell, or -granule level. Powerful tools such as multiphoton microscopy and transgenesis bear the promises of future developments of the field.
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Affiliation(s)
- Daniel Casellas
- Groupe Rein et Hypertension (EA3127), Institut Universitaire de Recherche Clinique, 641 Avenue du Doyen Giraud, 34093 Montpellier Cédex 5, France
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Inscho EW. ATP, P2 receptors and the renal microcirculation. Purinergic Signal 2009; 5:447-60. [PMID: 19294530 PMCID: PMC2776135 DOI: 10.1007/s11302-009-9147-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 05/16/2008] [Indexed: 01/22/2023] Open
Abstract
Purinoceptors are rapidly becoming recognised as important regulators of tissue and organ function. Renal expression of P2 receptors is broad and diverse, as reflected by the fact that P2 receptors have been identified in virtually every major tubular/vascular element. While P2 receptor expression by these renal structures is recognised, the physiological functions that they serve remains to be clarified. Renal vascular P2 receptor expression is complex and poorly understood. Evidence suggests that different complements of P2 receptors are expressed by individual renal vascular segments. This unique distribution has given rise to the postulate that P2 receptors are important for renal vascular function, including regulation of preglomerular resistance and autoregulatory behaviour. More recent studies have also uncovered evidence that hypertension reduces renal vascular reactivity to P2 receptor stimulation in concert with compromised autoregulatory capability. This review will consolidate findings related to the role of P2 receptors in regulating renal microvascular function and will present areas of controversy related to the respective roles of ATP and adenosine in autoregulatory resistance adjustments.
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Affiliation(s)
- Edward W Inscho
- Department of Physiology, Medical College of Georgia, Augusta, Georgia,
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Bell PD, Komlosi P, Zhang ZR. ATP as a mediator of macula densa cell signalling. Purinergic Signal 2009; 5:461-71. [PMID: 19330465 PMCID: PMC2776136 DOI: 10.1007/s11302-009-9148-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022] Open
Abstract
Within each nephro-vascular unit, the tubule returns to the vicinity of its own glomerulus. At this site, there are specialised tubular cells, the macula densa cells, which sense changes in tubular fluid composition and transmit information to the glomerular arterioles resulting in alterations in glomerular filtration rate and blood flow. Work over the last few years has characterised the mechanisms that lead to the detection of changes in luminal sodium chloride and osmolality by the macula densa cells. These cells are true "sensor cells" since intracellular ion concentrations and membrane potential reflect the level of luminal sodium chloride concentration. An unresolved question has been the nature of the signalling molecule(s) released by the macula densa cells. Currently, there is evidence that macula densa cells produce nitric oxide via neuronal nitric oxide synthase (nNOS) and prostaglandin E(2) (PGE(2)) through cyclooxygenase 2 (COX 2)-microsomal prostaglandin E synthase (mPGES). However, both of these signalling molecules play a role in modulating or regulating the macula-tubuloglomerular feedback system. Direct macula densa signalling appears to involve the release of ATP across the basolateral membrane through a maxi-anion channel in response to an increase in luminal sodium chloride concentration. ATP that is released by macula densa cells may directly activate P2 receptors on adjacent mesangial cells and afferent arteriolar smooth muscle cells, or the ATP may be converted to adenosine. However, the critical step in signalling would appear to be the regulated release of ATP across the basolateral membrane of macula densa cells.
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Affiliation(s)
- P Darwin Bell
- Department of Medicine, Division of Nephrology, Children's Research Institute, Medical University of South Carolina, Charleston, SC, USA,
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Dong B, Nishimura N, Vogel CF, Tohyama C, Matsumura F. TCDD-induced cyclooxygenase-2 expression is mediated by the nongenomic pathway in mouse MMDD1 macula densa cells and kidneys. Biochem Pharmacol 2009; 79:487-97. [PMID: 19782052 DOI: 10.1016/j.bcp.2009.08.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 08/21/2009] [Accepted: 08/24/2009] [Indexed: 01/15/2023]
Abstract
Cyclooxygenase-2 (Cox-2) plays a critical role in TCDD-induced hydronephrosis in mouse neonates. In this study we found that induction of Cox-2 by TCDD in MMDD1, a mouse macula densa cell line, is accompanied with a rapid increase in the enzymatic activity of cytosolic phospholipase A2 (cPLA2) as well as activation of protein kinases. Calcium serves as a trigger for such an action of TCDD in this cell line. These observations indicate that the basic mode of action of TCDD to induce the rapid inflammatory response in MMDD1 is remarkably similar to those mediated by the nongenomic pathway of aryl hydrocarbon receptor (AhR) found in other types of cells. Such an action of TCDD to induce Cox-2 in MMDD1 was not affected by "DRE decoy oligonucleotides" treatment or by introduction of a mutation on the DRE site of Cox-2 promoter, suggesting that this route of action of TCDD is clearly different from that mediated by the classical genomic pathway. An in vivo study with Ahr(nls) mouse model has shown that TCDD-induces Cox-2 and renin expression in the kidneys of the Ahr(nls) mice as well as Ahr(+/-) mice, but not in the Ahr(-/-) mice, indicating that this initial action of TCDD in mouse kidney does not require the translocation of AhR into the nucleus, supporting our conclusion that induction of Cox-2 by TCDD in mouse kidney is largely mediated by the nongenomic pathway of TCDD-activated AhR.
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Affiliation(s)
- Bin Dong
- Department of Environmental Toxicology, University of California, 4245 Meyer Hall, Davis, CA 95616, USA
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Guan Z, Pollock JS, Cook AK, Hobbs JL, Inscho EW. Effect of epithelial sodium channel blockade on the myogenic response of rat juxtamedullary afferent arterioles. Hypertension 2009; 54:1062-9. [PMID: 19720952 DOI: 10.1161/hypertensionaha.109.137992] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The mechanotransduction mechanism underlying the myogenic response is poorly understood, but evidence implicates participation of epithelial sodium channel (ENaC)-like proteins. Therefore, the role of ENaC on the afferent arteriolar myogenic response was investigated in vitro using the blood-perfused juxtamedullary nephron technique. Papillectomy was used to isolate myogenic influences by eliminating tubuloglomerular feedback signals. Autoregulatory responses were assessed by manipulating perfusion pressure in 30-mm Hg steps. Under control conditions, arteriolar diameter increased by 15% from 13.0+/-1.3 to 14.7+/-1.2 microm (P<0.05) after reducing perfusion pressure from 100 to 70 mm Hg. Diameter decreased to 11.3+/-1.1 and 10.6+/-1.0 microm after increasing pressure to 130 and 160 mm Hg (88+/-1 and 81+/-2% of control diameter, P<0.05), respectively. Pressure-mediated autoregulatory responses were significantly inhibited by superfusion of 10 micromol/L amiloride (102+/-2, 97+/-4, and 94+/-3% of control diameter), or 10 micromol/L benzamil (106+/-5, 100+/-3, and 103+/-3% of control diameter), and when perfusing with blood containing 5 micromol/L amiloride (106+/-2, 97+/-4, and 97+/-4% of control diameter). Vasoconstrictor responses to 55 mmol/L KCl were preserved as diameters decreased by 67+/-4, 55+/-8, and 60+/-4% in afferent arterioles superfused with amiloride or benzamil, and perfused with amiloride, respectively. These responses were similar to responses obtained from control afferent arterioles (64+/-6%, P>0.05). Immunofluorescence revealed expression of the alpha, beta, and gamma subunits of ENaC in freshly isolated preglomerular microvascular smooth muscle cells. These results demonstrate that selective ENaC inhibitors attenuate afferent arteriolar myogenic responses and suggest that ENaC may function as mechanosensitive ion channels initiating pressure-dependent myogenic responses in rat juxtamedullary afferent arterioles.
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Affiliation(s)
- Zhengrong Guan
- Department of Physiology, Medical College of Georgia, Augusta, GA 30912, USA
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