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Yip KP, Ribeiro-Silva L, Cha B, Rieg T, Sham JSK. Epac induces ryanodine receptor-dependent intracellular and inter-organellar calcium mobilization in mpkCCD cells. Front Physiol 2023; 14:1250273. [PMID: 37711462 PMCID: PMC10497751 DOI: 10.3389/fphys.2023.1250273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/11/2023] [Indexed: 09/16/2023] Open
Abstract
Arginine vasopressin (AVP) induces an increase in intracellular Ca2+ concentration ([Ca2+]i) with an oscillatory pattern in isolated perfused kidney inner medullary collecting duct (IMCD). The AVP-induced Ca2+ mobilization in inner medullary collecting ducts is essential for apical exocytosis and is mediated by the exchange protein directly activated by cyclic adenosine monophosphate (Epac). Murine principal kidney cortical collecting duct cells (mpkCCD) is the cell model used for transcriptomic and phosphoproteomic studies of AVP signaling in kidney collecting duct. The present study examined the characteristics of Ca2+ mobilization in mpkCCD cells, and utilized mpkCCD as a model to investigate the Epac-induced intracellular and intra-organellar Ca2+ mobilization. Ca2+ mobilization in cytosol, endoplasmic reticulum lumen, and mitochondrial matrix were monitored with a Ca2+ sensitive fluorescent probe and site-specific Ca2+ sensitive biosensors. Fluorescence images of mpkCCD cells and isolated perfused inner medullary duct were collected with confocal microscopy. Cell permeant ligands of ryanodine receptors (RyRs) and inositol 1,4,5 trisphosphate receptors (IP3Rs) both triggered increase of [Ca2+]i and Ca2+ oscillations in mpkCCD cells as reported previously in IMCD. The cell permeant Epac-specific cAMP analog Me-cAMP/AM also caused a robust Ca2+ mobilization and oscillations in mpkCCD cells. Using biosensors to monitor endoplasmic reticulum (ER) luminal Ca2+ and mitochondrial matrix Ca2+, Me-cAMP/AM not only triggered Ca2+ release from ER into cytoplasm, but also shuttled Ca2+ from ER into mitochondria. The Epac-agonist induced synchronized Ca2+ spikes in cytosol and mitochondrial matrix, with concomitant declines in ER luminal Ca2+. Me-cAMP/AM also effectively triggered store-operated Ca2+ entry (SOCE), suggesting that Epac-agonist is capable of depleting ER Ca2+ stores. These Epac-induced intracellular and inter-organelle Ca2+ signals were mimicked by the RyR agonist 4-CMC, but they were distinctly different from IP3R activation. The present study hence demonstrated that mpkCCD cells retain all reported features of Ca2+ mobilization observed in isolated perfused IMCD. It further revealed information on the dynamics of Epac-induced RyR-dependent Ca2+ signaling and ER-mitochondrial Ca2+ transfer. ER-mitochondrial Ca2+ coupling may play a key role in the regulation of ATP and reactive oxygen species (ROS) production in the mitochondria along the nephron. Our data suggest that mpkCCD cells can serve as a renal cell model to address novel questions of how mitochondrial Ca2+ regulates cytosolic Ca2+ signals, inter-organellar Ca2+ signaling, and renal tubular functions.
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Affiliation(s)
- Kay-Pong Yip
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
- Hypertension and Kidney Research Center, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Luisa Ribeiro-Silva
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Byeong Cha
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
- Hypertension and Kidney Research Center, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
- James A. Haley Veterans’ Hospital, Tampa, FL, United States
| | - James S. K. Sham
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Soares AG, Contreras J, Mironova E, Archer CR, Stockand JD, Abd El-Aziz TM. P2Y2 receptor decreases blood pressure by inhibiting ENaC. JCI Insight 2023; 8:e167704. [PMID: 37279066 PMCID: PMC10443811 DOI: 10.1172/jci.insight.167704] [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: 12/01/2022] [Accepted: 06/02/2023] [Indexed: 06/07/2023] Open
Abstract
Stimulating the Gq-coupled P2Y2 receptor (P2ry2) lowers blood pressure. Global knockout of P2ry2 increases blood pressure. Vascular and renal mechanisms are believed to participate in P2ry2 effects on blood pressure. To isolate the role of the kidneys in P2ry2 effects on blood pressure and to reveal the molecular and cellular mechanisms of this action, we test here the necessity of the P2ry2 and the sufficiency of Gq-dependent signaling in renal principal cells to the regulation of the epithelial Na+ channel (ENaC), sodium excretion, and blood pressure. Activating P2ry2 in littermate controls but not principal cell-specific P2ry2-knockout mice decreased the activity of ENaC in renal tubules. Moreover, deletion of P2ry2 in principal cells abolished increases in sodium excretion in response to stimulation of P2ry2 and compromised the normal ability to excrete a sodium load. Consequently, principal cell-specific knockout of P2ry2 prevented decreases in blood pressure in response to P2ry2 stimulation in the deoxycorticosterone acetate-salt (DOCA-salt) model of hypertension. In wild-type littermate controls, such stimulation decreased blood pressure in this model of hypertension by promoting a natriuresis. Pharmacogenetic activation of Gq exclusively in principal cells using targeted expression of Gq-designer receptors exclusively activated by designer drugs and clozapine N-oxide decreased the activity of ENaC in renal tubules, promoting a natriuresis that lowered elevated blood pressure in the DOCA-salt model of hypertension. These findings demonstrate that the kidneys play a major role in decreasing blood pressure in response to P2ry2 activation and that inhibition of ENaC activity in response to P2ry2-mediated Gq signaling lowered blood pressure by increasing renal sodium excretion.
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Affiliation(s)
- Antonio G. Soares
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Jorge Contreras
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Elena Mironova
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Crystal R. Archer
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - James D. Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Tarek Mohamed Abd El-Aziz
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Zoology Department, Faculty of Science, Minia University, El-Minia, Egypt
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3
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Purinoceptor: a novel target for hypertension. Purinergic Signal 2023; 19:185-197. [PMID: 35181831 PMCID: PMC9984596 DOI: 10.1007/s11302-022-09852-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/08/2022] [Indexed: 12/11/2022] Open
Abstract
Hypertension is the leading cause of morbidity and mortality globally among all cardiovascular diseases. Purinergic signalling plays a crucial role in hypertension through the sympathetic nerve system, neurons in the brain stem, carotid body, endothelium, immune system, renin-angiotensin system, sodium excretion, epithelial sodium channel activity (ENaC), and renal autoregulation. Under hypertension, adenosine triphosphate (ATP) is released as a cotransmitter from the sympathetic nerve. It mediates vascular tone mainly through P2X1R activation on smooth muscle cells and activation of P2X4R and P2YR on endothelial cells and also via interaction with other purinoceptors, showing dual effects. P2Y1R is linked to neurogenic hypertension. P2X7R and P2Y11R are potential targets for immune-related hypertension. P2X3R located on the carotid body is the most promising novel therapeutic target for hypertension. A1R, A2AR, A2BR, and P2X7R are all related to renal autoregulation, which contribute to both renal damage and hypertension. The main focus is on the evidence addressing the involvement of purinoceptors in hypertension and therapeutic interventions.
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Yue Q, Al-Khalili O, Moseley A, Yoshigi M, Wynne BM, Ma H, Eaton DC. PIP 2 Interacts Electrostatically with MARCKS-like Protein-1 and ENaC in Renal Epithelial Cells. BIOLOGY 2022; 11:biology11121694. [PMID: 36552204 PMCID: PMC9774185 DOI: 10.3390/biology11121694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/30/2022] [Accepted: 10/17/2022] [Indexed: 11/25/2022]
Abstract
We examined the interaction of a membrane-associated protein, MARCKS-like Protein-1 (MLP-1), and an ion channel, Epithelial Sodium Channel (ENaC), with the anionic lipid, phosphatidylinositol 4, 5-bisphosphate (PIP2). We found that PIP2 strongly activates ENaC in excised, inside-out patches with a half-activating concentration of 21 ± 1.17 µM. We have identified 2 PIP2 binding sites in the N-terminus of ENaC β and γ with a high concentration of basic residues. Normal channel activity requires MLP-1's strongly positively charged effector domain to electrostatically sequester most of the membrane PIP2 and increase the local concentration of PIP2. Our previous data showed that ENaC covalently binds MLP-1 so PIP2 bound to MLP-1 would be near PIP2 binding sites on the cytosolic N terminal regions of ENaC. We have modified the charge structure of the PIP2 -binding domains of MLP-1 and ENaC and showed that the changes affect membrane localization and ENaC activity in a way consistent with electrostatic theory.
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Affiliation(s)
- Qiang Yue
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Otor Al-Khalili
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Auriel Moseley
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Masaaki Yoshigi
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT 84132, USA
| | - Brandi Michele Wynne
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT 84132, USA
| | - Heping Ma
- Department of Physiology, Emory University, Atlanta, GA 30322, USA
| | - Douglas C. Eaton
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA 30322, USA
- Correspondence: ; Tel.: +1-404-727-4533; Fax: +1-404-727-3425
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Barros Lamus ER, Carotti V, de Vries CRS, Witsel F, Arntz OJ, van de Loo FAJ, Carvajal CA, Bindels RJM, Hoenderop JGJ, Rigalli JP. Extracellular vesicles regulate purinergic signaling and epithelial sodium channel expression in renal collecting duct cells. FASEB J 2021; 35:e21506. [PMID: 33811695 DOI: 10.1096/fj.202002559r] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/04/2021] [Accepted: 02/22/2021] [Indexed: 12/12/2022]
Abstract
Purinergic signaling regulates several renal physiological and pathophysiological processes. Extracellular vesicles (EVs) are nanoparticles released by most cell types, which, in non-renal tissues, modulate purinergic signaling. The aim of this study was to investigate the effect of EVs from renal proximal tubule (HK2) and collecting duct cells (HCD) on intra- and intersegment modulation of extracellular ATP levels, the underlying molecular mechanisms, and the impact on the expression of the alpha subunit of the epithelial sodium channel (αENaC). HK2 cells were exposed to HK2 EVs, while HCD cells were exposed to HK2 and HCD EVs. Extracellular ATP levels and αENaC expression were measured by chemiluminescence and qRT-PCR, respectively. ATPases in EV populations were identified by mass spectrometry. The effect of aldosterone was assessed using EVs from aldosterone-treated cells and urinary EVs (uEVs) from primary aldosteronism (PA) patients. HK2 EVs downregulated ectonucleoside-triphosphate-diphosphohydrolase-1 (ENTPD1) expression, increased extracellular ATP and downregulated αENaC expression in HCD cells. ENTPD1 downregulation could be attributed to increased miR-205-3p and miR-505 levels. Conversely, HCD EVs decreased extracellular ATP levels and upregulated αENaC expression in HCD cells, probably due to enrichment of 14-3-3 isoforms with ATPase activity. Pretreatment of donor cells with aldosterone or exposure to uEVs from PA patients enhanced the effects on extracellular ATP and αENaC expression. We demonstrated inter- and intrasegment modulation of renal purinergic signaling by EVs. Our findings postulate EVs as carriers of information along the renal tubules, whereby processes affecting EV release and/or cargo may impact on purinergically regulated processes.
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Affiliation(s)
- Eric R Barros Lamus
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valentina Carotti
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Christine R S de Vries
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Femke Witsel
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Onno J Arntz
- Department of Rheumatology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Fons A J van de Loo
- Department of Rheumatology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Cristian A Carvajal
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Juan P Rigalli
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
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Guo X, Li Q, Pi S, Xia Y, Mao L. G protein-coupled purinergic P2Y receptor oligomerization: Pharmacological changes and dynamic regulation. Biochem Pharmacol 2021; 192:114689. [PMID: 34274353 DOI: 10.1016/j.bcp.2021.114689] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 12/12/2022]
Abstract
P2Y receptors (P2YRs) are a δ group of rhodopsin-like G protein-coupled receptors (GPCRs) with many essential functions in physiology and pathology, such as platelet aggregation, immune responses, neuroprotective effects, inflammation, and cellular proliferation. Thus, they are among the most researched therapeutic targets used for the clinical treatment of diseases (e.g., the antithrombotic drug clopidogrel and the dry eye treatment drug diquafosol). GPCRs transmit signals as dimers to increase the diversity of signalling pathways and pharmacological activities. Many studies have frequently confirmed dimerization between P2YRs and other GPCRs due to their functions in cardiovascular and cerebrovascular processes in vivo and in vitro. Recently, some P2YR dimers that dynamically balance physiological functions in the body were shown to be involved in effective signal transduction and exert pathological responses. In this review, we summarize the types, pharmacological changes, and active regulators of P2YR-related dimerization, and delineate new functions and pharmacological activities of P2YR-related dimers, which may be a novel direction to improve the effectiveness of medications.
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Affiliation(s)
- Xiaoqing Guo
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qin Li
- Department of Vascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Shulan Pi
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yuanpeng Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Ling Mao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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Gohar EY, Kasztan M, Zhang S, Inscho EW, Pollock DM. Role for ovarian hormones in purinoceptor-dependent natriuresis. Biol Sex Differ 2020; 11:52. [PMID: 32928299 PMCID: PMC7490965 DOI: 10.1186/s13293-020-00329-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 09/01/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Premenopausal women have a lower risk of hypertension compared to age-matched men and postmenopausal women. P2Y2 and P2Y4 purinoceptor can be considered potential contributors to hypertension due to their emerging roles in regulating renal tubular Na+ transport. Activation of these receptors inhibits epithelial Na+ channel activity (ENaC) via a phospholipase C (PLC)-dependent pathway resulting in natriuresis. We recently reported that activation of P2Y2 and P2Y4 receptors in the renal medulla by UTP promotes natriuresis in male and ovariectomized (OVX) rats, but not in ovary-intact females. This led us to hypothesize that ovary-intact females have greater basal renal medullary activity of P2 (P2Y2 and P2Y4) receptors regulating Na+ excretion compared to male and OVX rats. METHODS To test our hypothesis, we determined (i) the effect of inhibiting medullary P2 receptors by suramin (750 μg/kg/min) on urinary Na+ excretion in anesthetized male, ovary-intact female, and OVX Sprague Dawley rats, (ii) mRNA expression and protein abundance of P2Y2 and P2Y4 receptors, and (iii) mRNA expression of their downstream effectors (PLC-1δ and ENaCα) in renal inner medullary tissues obtained from these three groups. We also subjected cultured mouse inner medullary collecting duct cells (segment 3, mIMCD3) to different concentrations of 17ß-estradiol (E2, 0, 10, 100, and 1000 nM) to test whether E2 increases mRNA expression of P2Y2 and P2Y4 receptors. RESULTS Acute P2 inhibition attenuated urinary Na+ excretion in ovary-intact females, but not in male or OVX rats. We found that P2Y2 and P2Y4 mRNA expression was higher in the inner medulla from females compared to males or OVX. Inner medullary lysates showed that ovary-intact females have higher P2Y2 receptor protein abundance, compared to males; however, OVX did not eliminate this sex difference. We also found that E2 dose-dependently upregulated P2Y2 and P2Y4 mRNA expression in mIMCD3. CONCLUSION These data suggest that ovary-intact females have enhanced P2Y2 and P2Y4-dependent regulation of Na+ handling in the renal medulla, compared to male and OVX rats. We speculate that the P2 pathway contributes to facilitated renal Na+ handling in premenopausal females.
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Affiliation(s)
- Eman Y Gohar
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, 720 20th St S, Kaul 840, Birmingham, AL, 35233, USA.
| | - Malgorzata Kasztan
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, 720 20th St S, Kaul 840, Birmingham, AL, 35233, USA
| | - Shali Zhang
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, 720 20th St S, Kaul 840, Birmingham, AL, 35233, USA
| | - Edward W Inscho
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, 720 20th St S, Kaul 840, Birmingham, AL, 35233, USA
| | - David M Pollock
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, 720 20th St S, Kaul 840, Birmingham, AL, 35233, USA
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Wall SM, Verlander JW, Romero CA. The Renal Physiology of Pendrin-Positive Intercalated Cells. Physiol Rev 2020; 100:1119-1147. [PMID: 32347156 PMCID: PMC7474261 DOI: 10.1152/physrev.00011.2019] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 11/06/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022] Open
Abstract
Intercalated cells (ICs) are found in the connecting tubule and the collecting duct. Of the three IC subtypes identified, type B intercalated cells are one of the best characterized and known to mediate Cl- absorption and HCO3- secretion, largely through the anion exchanger pendrin. This exchanger is thought to act in tandem with the Na+-dependent Cl-/HCO3- exchanger, NDCBE, to mediate net NaCl absorption. Pendrin is stimulated by angiotensin II and aldosterone administration via the angiotensin type 1a and the mineralocorticoid receptors, respectively. It is also stimulated in models of metabolic alkalosis, such as with NaHCO3 administration. In some rodent models, pendrin-mediated HCO3- secretion modulates acid-base balance. However, of probably more physiological or clinical significance is the role of these pendrin-positive ICs in blood pressure regulation, which occurs, at least in part, through pendrin-mediated renal Cl- absorption, as well as their effect on the epithelial Na+ channel, ENaC. Aldosterone stimulates ENaC directly through principal cell mineralocorticoid hormone receptor (ligand) binding and also indirectly through its effect on pendrin expression and function. In so doing, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. In addition to its role in Na+ and Cl- balance, pendrin affects the balance of other ions, such as K+ and I-. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contribution of pendrin-positive ICs in the kidney to distal nephron function and blood pressure.
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Affiliation(s)
- Susan M Wall
- Departments of Medicine and Physiology, Emory University School of Medicine, Atlanta, Georgia; and Department of Medicine, University of Florida, Gainesville, Florida
| | - Jill W Verlander
- Departments of Medicine and Physiology, Emory University School of Medicine, Atlanta, Georgia; and Department of Medicine, University of Florida, Gainesville, Florida
| | - Cesar A Romero
- Departments of Medicine and Physiology, Emory University School of Medicine, Atlanta, Georgia; and Department of Medicine, University of Florida, Gainesville, Florida
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Rao R, Bhalla V, Pastor-Soler NM. Intercalated Cells of the Kidney Collecting Duct in Kidney Physiology. Semin Nephrol 2020; 39:353-367. [PMID: 31300091 DOI: 10.1016/j.semnephrol.2019.04.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The epithelium of the kidney collecting duct (CD) is composed mainly of two different types of cells with distinct and complementary functions. CD principal cells traditionally have been considered to have a major role in Na+ and water regulation, while intercalated cells (ICs) were thought to largely modulate acid-base homeostasis. In recent years, our understanding of IC function has improved significantly owing to new research findings. Thus, we now have a new model for CD transport that integrates mechanisms of salt and water reabsorption, K+ homeostasis, and acid-base status between principal cells and ICs. There are three main types of ICs (type A, type B, and non-A, non-B), which first appear in the late distal convoluted tubule or in the connecting segment in a species-dependent manner. ICs can be detected in CD from cortex to the initial part of the inner medulla, although some transport proteins that are key components of ICs also are present in medullary CD, cells considered inner medullary. Of the three types of ICs, each has a distinct morphology and expresses different complements of membrane transport proteins that translate into very different functions in homeostasis and contributions to CD luminal pro-urine composition. This review includes recent discoveries in IC intracellular and paracrine signaling that contributes to acid-base regulation as well as Na+, Cl-, K+, and Ca2+ homeostasis. Thus, these new findings highlight the potential role of ICs as targets for potential hypertension treatments.
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Affiliation(s)
- Renee Rao
- University of Southern California/University Kidney Research Organization, Kidney Research Center, Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA
| | - Vivek Bhalla
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, CA
| | - Núria M Pastor-Soler
- University of Southern California/University Kidney Research Organization, Kidney Research Center, Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA.
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10
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Leipziger J, Praetorius H. Renal Autocrine and Paracrine Signaling: A Story of Self-protection. Physiol Rev 2020; 100:1229-1289. [PMID: 31999508 DOI: 10.1152/physrev.00014.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Autocrine and paracrine signaling in the kidney adds an extra level of diversity and complexity to renal physiology. The extensive scientific production on the topic precludes easy understanding of the fundamental purpose of the vast number of molecules and systems that influence the renal function. This systematic review provides the broader pen strokes for a collected image of renal paracrine signaling. First, we recapitulate the essence of each paracrine system one by one. Thereafter the single components are merged into an overarching physiological concept. The presented survey shows that despite the diversity in the web of paracrine factors, the collected effect on renal function may not be complicated after all. In essence, paracrine activation provides an intelligent system that perceives minor perturbations and reacts with a coordinated and integrated tissue response that relieves the work load from the renal epithelia and favors diuresis and natriuresis. We suggest that the overall function of paracrine signaling is reno-protection and argue that renal paracrine signaling and self-regulation are two sides of the same coin. Thus local paracrine signaling is an intrinsic function of the kidney, and the overall renal effect of changes in blood pressure, volume load, and systemic hormones will always be tinted by its paracrine status.
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Affiliation(s)
- Jens Leipziger
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
| | - Helle Praetorius
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
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11
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Zhang D, Pollock DM. Diurnal Regulation of Renal Electrolyte Excretion: The Role of Paracrine Factors. Annu Rev Physiol 2019; 82:343-363. [PMID: 31635525 DOI: 10.1146/annurev-physiol-021119-034446] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Many physiological processes, including most kidney-related functions, follow specific rhythms tied to a 24-h cycle. This is largely because circadian genes operate in virtually every cell type in the body. In addition, many noncanonical genes have intrinsic circadian rhythms, especially within the liver and kidney. This new level of complexity applies to the control of renal electrolyte excretion. Furthermore, there is growing evidence that paracrine and autocrine factors, especially the endothelin system, are regulated by clock genes. We have known for decades that excretion of electrolytes is dependent on time of day, which could play an important role in fluid volume balance and blood pressure control. Here, we review what is known about the interplay between paracrine and circadian control of electrolyte excretion. The hope is that recognition of paracrine and circadian factors can be considered more deeply in the future when integrating with well-established neuroendocrine control of excretion.
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Affiliation(s)
- Dingguo Zhang
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35233, USA; ,
| | - David M Pollock
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35233, USA; ,
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12
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Wu M, Liang C, Yu X, Song B, Yue Q, Zhai Y, Linck V, Cai Y, Niu N, Yang X, Zhang B, Wang Q, Zou L, Zhang S, Thai TL, Ma J, Sutliff RL, Zhang Z, Ma H. Lovastatin attenuates hypertension induced by renal tubule-specific knockout of ATP-binding cassette transporter A1, by inhibiting epithelial sodium channels. Br J Pharmacol 2019; 176:3695-3711. [PMID: 31222723 PMCID: PMC6715779 DOI: 10.1111/bph.14775] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 05/12/2019] [Accepted: 06/08/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE We have shown that cholesterol is synthesized in the principal cells of renal cortical collecting ducts (CCD) and stimulates the epithelial sodium channels (ENaC). Here we have determined whether lovastatin, a cholesterol synthesis inhibitor, can antagonize the hypertension induced by activated ENaC, following deletion of the cholesterol transporter (ATP-binding cassette transporter A1; ABCA1). EXPERIMENTAL APPROACH We selectively deleted ABCA1 in the principal cells of mouse CCD and used the cell-attached patch-clamp technique to record ENaC activity. Western blot and immunofluorescence staining were used to evaluate protein expression levels. Systolic BP was measured with the tail-cuff method. KEY RESULTS Specific deletion of ABCA1 elevated BP and ENaC single-channel activity in the principal cells of CCD in mice. These effects were antagonized by lovastatin. ABCA1 deletion elevated intracellular cholesterol levels, which was accompanied by elevated ROS, increased expression of serum/glucocorticoid regulated kinase 1 (Sgk1), phosphorylated neural precursor cell-expressed developmentally down-regulated protein 4-2 (Nedd4-2) and furin, along with shorten the primary cilium, and reduced ATP levels in urine. CONCLUSIONS AND IMPLICATIONS These data suggest that specific deletion of ABCA1 in principal cells increases BP by stimulating ENaC channels via a cholesterol-dependent pathway which induces several secondary responses associated with oxidative stress, activated Sgk1/Nedd4-2, increased furin expression, and reduced cilium-mediated release of ATP. As ABCA1 can be blocked by cyclosporine A, these results suggest further investigation of the possible use of statins to treat CsA-induced hypertension.
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Affiliation(s)
- Ming‐Ming Wu
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Chen Liang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Xiao‐Di Yu
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Bin‐Lin Song
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Qiang Yue
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Yu‐Jia Zhai
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Valerie Linck
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Yong‐Xu Cai
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Na Niu
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Xu Yang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Bao‐Long Zhang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Qiu‐Shi Wang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Li Zou
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Shuai Zhang
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Tiffany L. Thai
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Jing Ma
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of MedicineAtlanta Veterans Affairs Medical CenterDecaturGeorgia
| | - Roy L. Sutliff
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of MedicineAtlanta Veterans Affairs Medical CenterDecaturGeorgia
| | - Zhi‐Ren Zhang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - He‐Ping Ma
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
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Vallon V, Unwin R, Inscho EW, Leipziger J, Kishore BK. Extracellular Nucleotides and P2 Receptors in Renal Function. Physiol Rev 2019; 100:211-269. [PMID: 31437091 DOI: 10.1152/physrev.00038.2018] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The understanding of the nucleotide/P2 receptor system in the regulation of renal hemodynamics and transport function has grown exponentially over the last 20 yr. This review attempts to integrate the available data while also identifying areas of missing information. First, the determinants of nucleotide concentrations in the interstitial and tubular fluids of the kidney are described, including mechanisms of cellular release of nucleotides and their extracellular breakdown. Then the renal cell membrane expression of P2X and P2Y receptors is discussed in the context of their effects on renal vascular and tubular functions. Attention is paid to effects on the cortical vasculature and intraglomerular structures, autoregulation of renal blood flow, tubuloglomerular feedback, and the control of medullary blood flow. The role of the nucleotide/P2 receptor system in the autocrine/paracrine regulation of sodium and fluid transport in the tubular and collecting duct system is outlined together with its role in integrative sodium and fluid homeostasis and blood pressure control. The final section summarizes the rapidly growing evidence indicating a prominent role of the extracellular nucleotide/P2 receptor system in the pathophysiology of the kidney and aims to identify potential therapeutic opportunities, including hypertension, lithium-induced nephropathy, polycystic kidney disease, and kidney inflammation. We are only beginning to unravel the distinct physiological and pathophysiological influences of the extracellular nucleotide/P2 receptor system and the associated therapeutic perspectives.
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Affiliation(s)
- Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Robert Unwin
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Edward W Inscho
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Jens Leipziger
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Bellamkonda K Kishore
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
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14
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Mironova E, Suliman F, Stockand JD. Renal Na + excretion consequent to pharmacogenetic activation of G q-DREADD in principal cells. Am J Physiol Renal Physiol 2019; 316:F758-F767. [PMID: 30724104 PMCID: PMC6483033 DOI: 10.1152/ajprenal.00612.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/31/2019] [Accepted: 01/31/2019] [Indexed: 02/07/2023] Open
Abstract
Stimulation of metabotropic Gq-coupled purinergic P2Y2 receptors decreases activity of the epithelial Na+ channel (ENaC) in renal principal cells of the distal nephron. The physiological consequences of P2Y2 receptor signaling disruption in the P2Y2 receptor knockout mouse are decreased Na+ excretion and increased arterial blood pressure. However, because of the global nature of this knockout model, the quantitative contribution of ENaC and distal nephron compared with that of upstream renal vascular and tubular elements to changes in urinary excretion and arterial blood pressure is obscure. Moreover, it is uncertain whether stimulation of P2Y2 receptor inhibition of ENaC is sufficient to drive renal (urinary) Na+ excretion (UNaV). Here, using a pharmacogenetic approach and selective agonism of the P2Y2 receptor, we test the sufficiency of targeted stimulation of Gq signaling in principal cells of the distal nephron and P2Y2 receptors to increase UNaV. Selective stimulation of the P2Y2 receptor with the ligand MRS2768 decreased ENaC activity in freshly isolated tubules (as assessed by patch-clamp electrophysiology) and increased UNaV (as assessed in metabolic cages). Similarly, selective agonism of hM3Dq-designer receptors exclusively activated by designer drugs (DREADD) restrictively expressed in principal cells of the distal nephron with clozapine- N-oxide decreased ENaC activity and, consequently, increased UNaV. Clozapine- N-oxide, when applied to control littermates, failed to affect ENaC and UNaV. This study represents the first use of pharmacogenetic (DREADD) technology in the renal tubule and demonstrated that selective activation of the P2Y2 receptor and Gq signaling in principal cells is sufficient to promote renal salt excretion.
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Affiliation(s)
- Elena Mironova
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Faroug Suliman
- Division of Nephrology, Department of Internal Medicine, University of Michigan , Ann Arbor, Michigan
| | - James D Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
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15
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Mutchler SM, Kleyman TR. New insights regarding epithelial Na+ channel regulation and its role in the kidney, immune system and vasculature. Curr Opin Nephrol Hypertens 2019; 28:113-119. [PMID: 30585851 PMCID: PMC6349474 DOI: 10.1097/mnh.0000000000000479] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW This review describes recent findings regarding the epithelial Na channel (ENaC) and its roles in physiologic and pathophysiologic states. We discuss new insights regarding ENaC's structure, its regulation by various factors, its potential role in hypertension and nephrotic syndrome, and its roles in the immune system and vasculature. RECENT FINDINGS A recently resolved structure of ENaC provides clues regarding mechanisms of ENaC activation by proteases. The use of amiloride in nephrotic syndrome, and associated complications are discussed. ENaC is expressed in dendritic cells and contributes to immune system activation and increases in blood pressure in response to NaCl. ENaC is expressed in endothelial ENaC and has a role in regulating vascular tone. SUMMARY New findings have emerged regarding ENaC and its role in the kidney, immune system, and vasculature.
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Affiliation(s)
- Stephanie M. Mutchler
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA
| | - Thomas R. Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA
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16
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Characterization of purinergic receptor expression in ARPKD cystic epithelia. Purinergic Signal 2018; 14:485-497. [PMID: 30417216 DOI: 10.1007/s11302-018-9632-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 10/31/2018] [Indexed: 12/14/2022] Open
Abstract
Polycystic kidney diseases (PKDs) are a group of inherited nephropathies marked by formation of fluid-filled cysts along the nephron. Growing evidence suggests that in the kidney formation of cysts and alteration of cystic electrolyte transport are associated with purinergic signaling. PCK/CrljCrl-Pkhd1pck/CRL (PCK) rat, an established model of autosomal recessive polycystic kidney disease (ARPKD), was used here to test this hypothesis. Cystic fluid of PCK rats and their cortical tissues exhibited significantly higher levels of ATP compared to Sprague Dawley rat kidney cortical interstitium as assessed by highly sensitive ATP enzymatic biosensors. Confocal calcium imaging of the freshly isolated cystic monolayers revealed a stronger response to ATP in a higher range of concentrations (above 100 μM). The removal of extracellular calcium results in the profound reduction of the ATP evoked transient, which suggests calcium entry into the cyst-lining cells is occurring via the extracellular (ionotropic) P2X channels. Further use of pharmacological agents (α,β-methylene-ATP, 5-BDBD, NF449, isoPPADS, AZ10606120) and immunofluorescent labeling of isolated cystic epithelia allowed us to narrow down potential candidate receptors. In conclusion, our ex vivo study provides direct evidence that the profile of P2 receptors is shifted in ARPKD cystic epithelia in an age-related manner towards prevalence of P2X4 and/or P2X7 receptors, which opens new avenues for the treatment of this disease.
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17
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Craigie E, Menzies RI, Larsen CK, Jacquillet G, Carrel M, Wildman SS, Loffing J, Leipziger J, Shirley DG, Bailey MA, Unwin RJ. The renal and blood pressure response to low sodium diet in P2X4 receptor knockout mice. Physiol Rep 2018; 6:e13899. [PMID: 30350402 PMCID: PMC6198136 DOI: 10.14814/phy2.13899] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/25/2018] [Accepted: 09/27/2018] [Indexed: 01/02/2023] Open
Abstract
In the kidney, purinergic (P2) receptor-mediated ATP signaling has been shown to be an important local regulator of epithelial sodium transport. Appropriate sodium regulation is crucial for blood pressure (BP) control and disturbances in sodium balance can lead to hypo- or hypertension. Links have already been established between P2 receptor signaling and the development of hypertension, attributed mainly to vascular and/or inflammatory effects. A transgenic mouse model with deletion of the P2X4 receptor (P2X4-/- ) is known to have hypertension, which is thought to reflect endothelial dysfunction and impaired nitric oxide (NO) release. However, renal function in this model has not been characterized; moreover, studies in vitro have shown that the P2X4 receptor can regulate renal epithelial Na+ channel (ENaC) activity. Therefore, in the present study we investigated renal function and sodium handling in P2X4-/- mice, focusing on ENaC-mediated Na+ reabsorption. We confirmed an elevated BP in P2X4-/- mice compared with wild-type mice, but found that ENaC-mediated Na+ reabsorption is no different from wild-type and does not contribute to the raised BP observed in the knockout. However, when P2X4-/- mice were placed on a low sodium diet, BP normalized. Plasma aldosterone concentration tended to increase according to sodium restriction status in both genotypes; in contrast to wild-types, P2X4-/- mice did not show an increase in functional ENaC activity. Thus, although the increased BP in P2X4-/- mice has been attributed to endothelial dysfunction and impaired NO release, there is also a sodium-sensitive component.
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Affiliation(s)
- Eilidh Craigie
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
- Institue for AnatomyUniversity of ZürichZürichSwitzerland
| | - Robert I. Menzies
- British Heart Foundation Centre for Cardiovascular ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Casper K. Larsen
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - Grégory Jacquillet
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
| | - Monique Carrel
- Institue for AnatomyUniversity of ZürichZürichSwitzerland
| | - Scott S. Wildman
- Urinary System Physiology UnitMedway School of PharmacyUniversity of KentKentUnited Kingdom
| | | | - Jens Leipziger
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - David G. Shirley
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
| | - Matthew A. Bailey
- British Heart Foundation Centre for Cardiovascular ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Robert J. Unwin
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
- CVRM iMEDAstraZeneca GothenburgGothenburgSweden
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18
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Cao Q, Gu J, Wang D, Liang F, Zhang H, Li X, Yin S. Physiological mechanism of osmoregulatory adaptation in anguillid eels. FISH PHYSIOLOGY AND BIOCHEMISTRY 2018; 44:423-433. [PMID: 29344774 PMCID: PMC5862950 DOI: 10.1007/s10695-018-0464-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 01/03/2018] [Indexed: 06/07/2023]
Abstract
In recent years, the production of eel larvae has dramatic declines due to reductions in spawning stocks, overfishing, growth habitat destruction and access reductions, and pollution. Therefore, it is particularly important and urgent for artificial production of glass eels. However, the technique of artificial hatching and rearing larvae is still immature, which has long been regarded as an extremely difficult task. One of the huge gaps is artificial condition which is far from the natural condition to develop their capability of osmoregulation. Thus, understanding their osmoregulatory mechanisms will help to improve the breed and adapt to the changes in the environment. In this paper, we give a general review for a study progress of osmoregulatory mechanisms in eels from five aspects including tissues and organs, ion transporters, hormones, proteins, and high throughput sequencing methods.
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Affiliation(s)
- Quanquan Cao
- College of Life Sciences, Key Laboratory of Biodiversity and Biotechnology of Jiangsu Province, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu Province, 210023, China
| | - Jie Gu
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Dan Wang
- College of Life Sciences, Key Laboratory of Biodiversity and Biotechnology of Jiangsu Province, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu Province, 210023, China
| | - Fenfei Liang
- College of Life Sciences, Key Laboratory of Biodiversity and Biotechnology of Jiangsu Province, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu Province, 210023, China
| | - Hongye Zhang
- College of Life Sciences, Key Laboratory of Biodiversity and Biotechnology of Jiangsu Province, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu Province, 210023, China
| | - Xinru Li
- College of Life Sciences, Key Laboratory of Biodiversity and Biotechnology of Jiangsu Province, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu Province, 210023, China
| | - Shaowu Yin
- College of Life Sciences, Key Laboratory of Biodiversity and Biotechnology of Jiangsu Province, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu Province, 210023, China.
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Nishimura A, Sunggip C, Oda S, Numaga-Tomita T, Tsuda M, Nishida M. Purinergic P2Y receptors: Molecular diversity and implications for treatment of cardiovascular diseases. Pharmacol Ther 2017. [DOI: 10.1016/j.pharmthera.2017.06.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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20
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Wall SM. Renal intercalated cells and blood pressure regulation. Kidney Res Clin Pract 2017; 36:305-317. [PMID: 29285423 PMCID: PMC5743040 DOI: 10.23876/j.krcp.2017.36.4.305] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022] Open
Abstract
Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl- absorption and HCO3- secretion largely through pendrin-dependent Cl-/HCO3- exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO3 administration. In some rodent models, pendrin-mediated HCO3- secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl- absorption, but also by modulating the aldosterone response for epithelial Na+ channel (ENaC)-mediated Na+ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.
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Affiliation(s)
- Susan M. Wall
- Departments of Medicine, Emory University School of Medicine, Atlanta, GA,
USA
- Physiology, Emory University School of Medicine, Atlanta, GA,
USA
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21
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Palygin O, Evans LC, Cowley AW, Staruschenko A. Acute In Vivo Analysis of ATP Release in Rat Kidneys in Response to Changes of Renal Perfusion Pressure. J Am Heart Assoc 2017; 6:JAHA.117.006658. [PMID: 28899893 PMCID: PMC5634305 DOI: 10.1161/jaha.117.006658] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background ATP and derivatives are recognized to be essential agents of paracrine signaling. It was reported that ATP is an important regulator of the pressure‐natriuresis mechanism. Information on the sources of ATP, the mechanisms of its release, and its relationship to blood pressure has been limited by the inability to precisely measure dynamic changes in intrarenal ATP levels in vivo. Methods and Results Newly developed amperometric biosensors were used to assess alterations in cortical ATP concentrations in response to changes in renal perfusion pressure (RPP) in anesthetized Sprague–Dawley rats. RPP was monitored via the carotid artery; ligations around the celiac/superior mesenteric arteries and the distal aorta were used for manipulation of RPP. Biosensors were acutely implanted in the renal cortex for assessment of ATP. Rise of RPP activated diuresis/natriuresis processes, which were associated with elevated ATP. The increases in cortical ATP concentrations were in the physiological range (1–3 μmol/L) and would be capable of activating most of the purinergic receptors. There was a linear correlation with every 1‐mm Hg rise in RPP resulting in a 70‐nmol/L increase in ATP. Furthermore, this elevation of RPP was accompanied by a 2.5‐fold increase in urinary H2O2. Conclusions Changes in RPP directly correlate with renal sodium excretion and the elevation of cortical ATP. Given the known effects of ATP on regulation of glomerular filtration and tubular transport, the data support a role for ATP release in the rapid natriuretic responses to acute increases in RPP.
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Affiliation(s)
- Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI
| | - Louise C Evans
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI
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Wang ZR, Liu HB, Sun YY, Hu QQ, Li YX, Zheng WW, Yu CJ, Li XY, Wu MM, Song BL, Mu JJ, Yuan ZY, Zhang ZR, Ma HP. Dietary salt blunts vasodilation by stimulating epithelial sodium channels in endothelial cells from salt-sensitive Dahl rats. Br J Pharmacol 2017; 175:1305-1317. [PMID: 28409833 DOI: 10.1111/bph.13817] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/26/2017] [Accepted: 04/04/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Our recent studies show that the reduced activity of epithelial sodium channels (ENaC) in endothelial cells accounts for the adaptation of vasculature to salt in Sprague-Dawley rats. The present study examines a hypothesis that enhanced ENaC activity mediates the loss of vasorelaxation in Dahl salt-sensitive (SS) rats. EXPERIMENTAL APPROACH We used the cell-attached patch-clamp technique to record ENaC activity in split-open mesenteric arteries. Western blot and immunofluorescence staining were used to evaluate the levels of aldosterone, ENaC, eNOS and NO. Blood pressure was measured with the tail-cuff method and the artery relaxation was measured with the wire myograph assay. KEY RESULTS High-salt (HS) diet significantly increased plasma aldosterone and ENaC activity in the endothelial cells of Dahl SS rats. The endothelium-dependent artery relaxation was blunted by HS challenge in these rats. Amiloride, a potent blocker of ENaC, increased both phosphorylated eNOS and NO and therefore prevented the HS-induced loss of vasorelaxation. As, in SS rats, endogenous aldosterone was already elevated by HS challenge, exogenous aldosterone did not further elevate ENaC activity in the rats fed with HS. Eplerenone, a mineralocorticoid receptor antagonist, attenuated the effects of HS on both ENaC activity and artery relaxation. CONCLUSIONS AND IMPLICATIONS These data suggest that HS diet blunts artery relaxation and causes hypertension via a pathway associated with aldosterone-dependent activation of ENaC in endothelial cells. This pathway provides one of the mechanisms by which HS causes hypertension in Dahl SS rats. LINKED ARTICLES This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.
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Affiliation(s)
- Zi-Rui Wang
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Hui-Bin Liu
- Department of Clinical Pharmacy, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Ying-Ying Sun
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qing-Qing Hu
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Yu-Xia Li
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Wei-Wan Zheng
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Chang-Jiang Yu
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Xin-Yuan Li
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Ming-Ming Wu
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Bin-Lin Song
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Jian-Jun Mu
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Key Laboratory of Molecular Cardiology, Xi'an, China
| | - Zu-Yi Yuan
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Key Laboratory of Molecular Cardiology, Xi'an, China
| | - Zhi-Ren Zhang
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China.,Department of Clinical Pharmacy, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Harbin, China
| | - He-Ping Ma
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, USA
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Gohar EY, Kasztan M, Becker BK, Speed JS, Pollock DM. Ovariectomy uncovers purinergic receptor activation of endothelin-dependent natriuresis. Am J Physiol Renal Physiol 2017; 313:F361-F369. [PMID: 28468962 DOI: 10.1152/ajprenal.00098.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 04/17/2017] [Accepted: 04/28/2017] [Indexed: 12/13/2022] Open
Abstract
We recently reported that natriuresis produced by renal medullary salt loading is dependent on endothelin (ET)-1 and purinergic (P2) receptors in male rats. Because sex differences in ET-1 and P2 signaling have been reported, we decided to test whether ovarian sex hormones regulate renal medullary ET-1 and P2-dependent natriuresis. The effect of medullary NaCl loading on Na+ excretion was determined in intact and ovariectomized (OVX) female Sprague-Dawley rats with and without ET-1 or P2 receptor antagonism. Isosmotic saline (284 mosmol/kgH2O) was infused in the renal medullary interstitium of anesthetized rats during a baseline urine collection period, followed by isosmotic or hyperosmotic saline (1,800 mosmol/kgH2O) infusion. Medullary NaCl loading significantly enhanced Na+ excretion in intact and OVX female rats. ETA+B or P2 receptor blockade did not attenuate the natriuretic effect of medullary NaCl loading in intact females, whereas ETA+B or P2 receptor blockade attenuated the natriuretic response to NaCl loading in OVX rats. Activation of medullary P2Y2 and P2Y4 receptors by UTP infusion had no significant effect in intact females but enhanced Na+ excretion in OVX rats. Combined ETA+B receptor blockade significantly inhibited the natriuretic response to UTP observed in OVX rats. These data demonstrate that medullary NaCl loading induces ET-1 and P2-independent natriuresis in intact females. In OVX, activation of medullary P2 receptors promotes ET-dependent natriuresis, suggesting that ovarian hormones may regulate the interplay between the renal ET-1 and P2 signaling systems to facilitate Na+ excretion.
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Affiliation(s)
- Eman Y Gohar
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Malgorzata Kasztan
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Bryan K Becker
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Joshua S Speed
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David M Pollock
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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Gohar EY, Kasztan M, Pollock DM. Interplay between renal endothelin and purinergic signaling systems. Am J Physiol Renal Physiol 2017; 313:F666-F668. [PMID: 28179257 DOI: 10.1152/ajprenal.00639.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/30/2017] [Accepted: 02/01/2017] [Indexed: 12/19/2022] Open
Abstract
Alterations in extracellular fluid volume regulation and sodium balance may result in the development and maintenance of salt-dependent hypertension, a major risk factor for cardiovascular disease. Numerous pathways contribute to the regulation of sodium excretion and blood pressure, including endothelin and purinergic signaling. Increasing evidence suggests a link between purinergic receptor activation and endothelin production within the renal collecting duct as a means of promoting natriuresis. A better understanding of the relationship between these two systems, especially in regard to sodium homeostasis, will fill a significant knowledge gap and may provide novel antihypertensive treatment options. Therefore, this review focuses on the cross talk between endothelin and purinergic signaling as it relates to the renal regulation of sodium and blood pressure homeostasis.
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Affiliation(s)
- Eman Y Gohar
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Malgorzata Kasztan
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David M Pollock
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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25
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Mironova E, Lynch IJ, Berman JM, Gumz ML, Stockand JD, Wingo CS. ENaC activity in the cortical collecting duct of HKα 1 H +,K +-ATPase knockout mice is uncoupled from Na + intake. Am J Physiol Renal Physiol 2017; 312:F1073-F1080. [PMID: 28179253 DOI: 10.1152/ajprenal.00401.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 02/02/2017] [Accepted: 02/02/2017] [Indexed: 11/22/2022] Open
Abstract
Modulation of the epithelial Na+ channel (ENaC) activity in the collecting duct (CD) is an important mechanism for normal Na+ homeostasis. ENaC activity is inversely related to dietary Na+ intake, in part due to inhibitory paracrine purinergic regulation. Evidence suggests that H+,K+-ATPase activity in the CD also influences Na+ excretion. We hypothesized that renal H+,K+-ATPases affect Na+ reabsorption by the CD by modulating ENaC activity. ENaC activity in HKα1 H+,K+-ATPase knockout (HKα1-/-) mice was uncoupled from Na+ intake. ENaC activity on a high-Na+ diet was greater in the HKα1-/- mice than in WT mice. Moreover, dietary Na+ content did not modulate ENaC activity in the HKα1-/- mice as it did in WT mice. Purinergic regulation of ENaC was abnormal in HKα1-/- mice. In contrast to WT mice, where urinary [ATP] was proportional to dietary Na+ intake, urinary [ATP] did not increase in response to a high-Na+ diet in the HKα1-/- mice and was significantly lower than in the WT mice. HKα1-/- mice fed a high-Na+ diet had greater Na+ retention than WT mice and had an impaired dipsogenic response. These results suggest an important role for the HKα1 subunit in the regulation of purinergic signaling in the CD. They are also consistent with HKα1-containing H+,K+-ATPases as important components for the proper regulation of Na+ balance and the dipsogenic response to a high-salt diet. Such observations suggest a previously unrecognized element in Na+ regulation in the CD.
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Affiliation(s)
- Elena Mironova
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas
| | - I Jeanette Lynch
- North Florida/South Georgia Veterans Health Service, Gainesville, Florida; and.,Department of Medicine, University of Florida, Gainesville, Florida
| | - Jonathan M Berman
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas
| | - Michelle L Gumz
- North Florida/South Georgia Veterans Health Service, Gainesville, Florida; and.,Department of Medicine, University of Florida, Gainesville, Florida
| | - James D Stockand
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas
| | - Charles S Wingo
- North Florida/South Georgia Veterans Health Service, Gainesville, Florida; and .,Department of Medicine, University of Florida, Gainesville, Florida
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26
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Svendsen SL, Isidor S, Praetorius HA, Leipziger J. P2X Receptors Inhibit NaCl Absorption in mTAL Independently of Nitric Oxide. Front Physiol 2017; 8:18. [PMID: 28174542 PMCID: PMC5258741 DOI: 10.3389/fphys.2017.00018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 01/10/2017] [Indexed: 12/19/2022] Open
Abstract
Activation of basolateral P2X receptors markedly reduces NaCl absorption in mouse medullary thick ascending limb (mTAL). Here we tested the role of nitric oxide (NO) in the ATP-mediated (P2X) transport inhibition. We used isolated, perfused mTALs from mice to electrically measure NaCl absorption. By microelectrodes we determined the transepithelial voltage (Vte) and transepithelial resistance (Rte). Via these two parameters, we calculated the equivalent short circuit current, I'sc as a measure of the transepithelial Na+ absorption. Basolateral ATP (100 μM) acutely induced reversible inhibition of Na+ absorption (24 ± 4%, n = 10). Addition of L-arginine (100 μM) had no apparent effect on the ATP-induced transport inhibition. Acute reduction of extracellular [Ca2+] to either 100 nM or 0 nM by addition of EGTA had no effect on the ATP-induced transport inhibition. In the presence of the NO synthase (NOS) inhibitor L-NAME (100 μM) and/or ODQ to inhibit the guanylyl cyclase, the ATP effect remained unaffected. Increasing the concentration and incubation time for L-NAME (1 mM) still did not reveal any effect on the ATP-mediated transport inhibition. Acute addition of the NO donors SNAP (100 μM) and Spermine NONOate (10 μM) did not alter tubular transport. High concentrations of L-NAME (1 mM) in itself, however, reduced the transepithelial transport significantly. Thus, we find no evidence for nitric oxide (NO) as second messenger for P2X receptor-dependent transport inhibition in mTAL. Moreover, Ca2+ signaling appears not involved in the ATP-mediated effect. It remains undefined how P2X receptors trigger the marked reduction of transport in the TAL.
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Affiliation(s)
- Samuel L Svendsen
- Department of Biomedicine, Physiology, Aarhus University Aarhus, Denmark
| | - Søren Isidor
- Department of Biomedicine, Physiology, Aarhus University Aarhus, Denmark
| | - Helle A Praetorius
- Department of Biomedicine, Physiology, Aarhus University Aarhus, Denmark
| | - Jens Leipziger
- Department of Biomedicine, Physiology, Aarhus University Aarhus, Denmark
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27
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Wu MM, Zhai YJ, Li YX, Hu QQ, Wang ZR, Wei SP, Zou L, Alli AA, Thai TL, Zhang ZR, Ma HP. Hydrogen peroxide suppresses TRPM4 trafficking to the apical membrane in mouse cortical collecting duct principal cells. Am J Physiol Renal Physiol 2016; 311:F1360-F1368. [PMID: 27956381 DOI: 10.1152/ajprenal.00439.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/31/2016] [Accepted: 10/31/2016] [Indexed: 01/14/2023] Open
Abstract
A Ca2+-activated nonselective cation channel (NSCCa) is found in principal cells of the mouse cortical collecting duct (CCD). However, the molecular identity of this channel remains unclear. We used mpkCCDc14 cells, a mouse CCD principal cell line, to determine whether NSCCa represents the transient receptor potential (TRP) channel, the melastatin subfamily 4 (TRPM4). A Ca2+-sensitive single-channel current was observed in inside-out patches excised from the apical membrane of mpkCCDc14 cells. Like TRPM4 channels found in other cell types, this channel has an equal permeability for Na+ and K+ and has a linear current-voltage relationship with a slope conductance of ~23 pS. The channel was inhibited by a specific TRPM4 inhibitor, 9-phenanthrol. Moreover, the frequency of observing this channel was dramatically decreased in TRPM4 knockdown mpkCCDc14 cells. Unlike those previously reported in other cell types, the TRPM4 in mpkCCDc14 cells was unable to be activated by hydrogen peroxide (H2O2). Conversely, after treatment with H2O2, TRPM4 density in the apical membrane of mpkCCDc14 cells was significantly decreased. The channel in intact cell-attached patches was activated by ionomycin (a Ca2+ ionophore), but not by ATP (a purinergic P2 receptor agonist). These data suggest that the NSCCa current previously described in CCD principal cells is actually carried through TRPM4 channels. However, the physiological role of this channel in the CCD remains to be further determined.
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Affiliation(s)
- Ming-Ming Wu
- Departments of Cardiology and Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Harbin, China; and.,Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Yu-Jia Zhai
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Yu-Xia Li
- Departments of Cardiology and Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Harbin, China; and
| | - Qing-Qing Hu
- Departments of Cardiology and Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Harbin, China; and
| | - Zhi-Rui Wang
- Departments of Cardiology and Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Harbin, China; and
| | - Shi-Peng Wei
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Li Zou
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Abdel A Alli
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Tiffany L Thai
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Zhi-Ren Zhang
- Departments of Cardiology and Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Harbin, China; and
| | - He-Ping Ma
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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28
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Menzies RI, Tam FW, Unwin RJ, Bailey MA. Purinergic signaling in kidney disease. Kidney Int 2016; 91:315-323. [PMID: 27780585 DOI: 10.1016/j.kint.2016.08.029] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/10/2016] [Accepted: 08/15/2016] [Indexed: 02/04/2023]
Abstract
Nucleotides are key subunits for nucleic acids and provide energy for intracellular metabolism. They can also be released from cells to act physiologically as extracellular messengers or pathologically as danger signals. Extracellular nucleotides stimulate membrane receptors in the P2 and P1 family. P2X are ATP-activated cation channels; P2Y and P1 are G-protein coupled receptors activated by ATP, ADP, UTP, and UDP in the case of P2 or adenosine for P1. Renal P2 receptors influence both vascular contractility and tubular function. Renal cells also express ectonucleotidases that rapidly hydrolyze extracellular nucleotides. These enzymes integrate this multireceptor purinergic-signaling complex by determining the nucleotide milieu to titrate receptor activation. Purinergic signaling also regulates immune cell function by modulating the synthesis and release of various cytokines such as IL1-β and IL-18 as part of inflammasome activation. Abnormal or excessive stimulation of this intricate paracrine system can be pro- or anti-inflammatory, and is also linked to necrosis and apoptosis. Kidney tissue injury causes a localized increase in ATP concentration, and sustained activation of P2 receptors can lead to renal glomerular, tubular, and vascular cell damage. Purinergic receptors also regulate the activity and proliferation of fibroblasts, promoting both inflammation and fibrosis in chronic disease. In this short review we summarize some of the recent findings related to purinergic signaling in the kidney. We focus predominantly on the P2X7 receptor, discussing why antagonists have so far disappointed in clinical trials and how advances in our understanding of purinergic signaling might help to reposition these compounds as potential treatments for renal disease.
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Affiliation(s)
- Robert I Menzies
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, Scotland, UK
| | - Frederick W Tam
- Imperial College Renal and Transplant Centre, Department of Medicine, Imperial College London, UK
| | - Robert J Unwin
- Cardiovascular and Metabolic Diseases Biotech Unit, AstraZeneca Gothenburg, Sweden; UCL Centre for Nephrology, University College London, London, UK.
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, Scotland, UK
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29
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Ilatovskaya DV, Palygin O, Staruschenko A. Functional and therapeutic importance of purinergic signaling in polycystic kidney disease. Am J Physiol Renal Physiol 2016; 311:F1135-F1139. [PMID: 27654892 DOI: 10.1152/ajprenal.00406.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/20/2016] [Indexed: 12/12/2022] Open
Abstract
Polycystic kidney diseases (PKD) are a group of inherited nephropathies marked with the formation of fluid-filled cysts along the nephron. This renal disorder affects millions of people worldwide, but current treatment strategies are unfortunately limited to supportive therapy, dietary restrictions, and, eventually, renal transplantation. Recent advances in PKD management are aimed at targeting exaggerated cell proliferation and dedifferentiation to interfere with cyst growth. However, not nearly enough is known about the ion transport properties of the cystic cells, or specific signaling pathways modulating channels and transporters in this condition. There is growing evidence that abnormally elevated concentrations of adenosine triphosphate (ATP) in PKD may contribute to cyst enlargement; change in the profile of purinergic receptors may also result in promotion of cystogenesis. The current mini-review is focused on the role of ATP and associated signaling affecting ion transport properties of the renal cystic epithelia.
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Affiliation(s)
- Daria V Ilatovskaya
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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30
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Gohar EY, Speed JS, Kasztan M, Jin C, Pollock DM. Activation of purinergic receptors (P2) in the renal medulla promotes endothelin-dependent natriuresis in male rats. Am J Physiol Renal Physiol 2016; 311:F260-7. [PMID: 27226106 DOI: 10.1152/ajprenal.00090.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/19/2016] [Indexed: 11/22/2022] Open
Abstract
Renal endothelin-1 (ET-1) and purinergic signaling systems regulate Na(+) reabsorption in the renal medulla. A link between the renal ET-1 and purinergic systems was demonstrated in vitro, however, the in vivo interaction between these systems has not been defined. To test whether renal medullary activation of purinergic (P2) receptors promotes ET-dependent natriuresis, we determined the effect of increased medullary NaCl loading on Na(+) excretion and inner medullary ET-1 mRNA expression in anesthetized adult male Sprague-Dawley rats in the presence and absence of purinergic receptor antagonism. Isosmotic saline (NaCl; 284 mosmol/kgH2O) was infused into the medullary interstitium (500 μl/h) during a 30-min baseline urine collection period, followed by isosmotic or hyperosmotic saline (1,800 mosmol/kgH2O) for two further 30-min urine collection periods. Na(+) excretion was significantly increased during intramedullary infusion of hyperosmotic saline. Compared with isosmotic saline, hyperosmotic saline infused into the renal medulla caused significant increases in inner medullary ET-1 mRNA expression. Renal intramedullary infusion of the P2 receptor antagonist suramin inhibited the increase in Na(+) excretion and inner medullary ET-1 mRNA expression induced by NaCl loading in the renal medulla. Activation of medullary P2Y2/4 receptors by infusion of UTP increased urinary Na(+) excretion. Combined ETA and ETB receptor blockade abolished the natriuretic response to intramedullary infusion of UTP. These data demonstrate that activation of medullary P2 receptors promotes ET-dependent natriuresis in male rats, suggesting that the renal ET-1 and purinergic signaling systems interact to efficiently facilitate excretion of a NaCl load.
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Affiliation(s)
- Eman Y Gohar
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Joshua S Speed
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Malgorzata Kasztan
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Chunhua Jin
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David M Pollock
- Cardio-Renal Physiology & Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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31
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Mei Y, Yangyang Z, Shuai L, Hao J, Yirong Y, Yong C, Peng X, Bicheng C, Yan Z. Breviscapine prevents downregulation of renal water and sodium transport proteins in response to unilateral ureteral obstruction. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2016. [PMID: 27403265 PMCID: PMC4923479 DOI: 10.22038/ijbms.2016.6943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Our recent report indicates that breviscapine play a protective role of the kidney by down-regulating transforming growth factor-β1(TGF-β1), α-smooth muscle actin (α-SMA) and alleviating interstitial fibrosis following unilateral ureteral obstruction (UUO). In this study, we investigate the effect of breviscapine on changes of renal water and sodium transport proteins in response to UUO. MATERIALS AND METHODS Male Sprague-Dawley rats were divided into 3 groups, sham group, UUO group and UUO treat with breviscapine. After 4, 7 and 14 days, histologic changes and interstitial collagen were determined microscopically following hematoxylin and eosin (H&E) and Masson's trichrome staining. The expression of Aquaporins (AQP-2) and γ-epithelial sodium channel (γ-ENaC) were investigated using immunohistochemistry and Western blot in each group. RESULTS Breviscapine treatment decrease the tubular injury index and the degree of interstitial collagen deposition significantly compared with the UUO group (P<0.05). Breviscapine treatment also significantly reduced downregulation of AQP2 and γ-ENaC compared to those subjected to the same time course of obstruction in UUO group (P<0.05). CONCLUSION These results demonstrate that breviscapine could prevent downregulation of renal water and sodium transport proteins in response to UUO so as to protect obstructed kidney.
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Affiliation(s)
- Yang Mei
- Department of Intensive Care Unit, The First Affiliate Hospital of Wenzhou Medical University, China
| | - Zhuang Yangyang
- Department of Intensive Care Unit, The First Affiliate Hospital of Wenzhou Medical University, China
| | - Luo Shuai
- Department of Transplantation Center, The First Affiliate Hospital of Wenzhou Medical University, China
| | - Jin Hao
- Department of Transplantation Center, The First Affiliate Hospital of Wenzhou Medical University, China
| | - Yang Yirong
- Department of Transplantation Center, The First Affiliate Hospital of Wenzhou Medical University, China
| | - Cai Yong
- Department of Transplantation Center, The First Affiliate Hospital of Wenzhou Medical University, China
| | - Xia Peng
- Department of Transplantation Center, The First Affiliate Hospital of Wenzhou Medical University, China
| | - Chen Bicheng
- Key Laboratory of Surgery, Department of Surgery, The First Affiliated Hospital of Wenzhou Medical University, China
| | - Zhang Yan
- Department of Transplantation Center, The First Affiliate Hospital of Wenzhou Medical University, China,Corresponding author: Zhang Yan. Department of Transplantation Center, The First Affiliate Hospital of Wenzhou Medical University, 1 Fuxuexiang, Wenzhou, Zhejiang, China. Tel: +86-577-55579478;
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Abstract
Pendrin is a Na(+)-independent Cl(-)/HCO3(-) exchanger found in the apical regions of type B and non-A, non-B intercalated cells within the aldosterone-sensitive region of the nephron, i.e., the distal convoluted tubule (DCT), the connecting tubule (CNT), and the cortical collecting duct (CCD). Type B intercalated cells mediate Cl(-) absorption and HCO3(-) secretion primarily through pendrin-mediated Cl(-)/HCO3(-) exchange. This exchanger is upregulated with angiotensin II administration and in models of metabolic alkalosis, such as following administration of aldosterone or NaHCO3. In the absence of pendrin-mediated HCO3(-) secretion, an enhanced alkalosis is observed following aldosterone or NaHCO3 administration. However, probably of more significance is the role of pendrin in the pressor response to aldosterone. Pendrin mediates Cl(-) absorption and modulates aldosterone-induced Na(+) absorption mediated by the epithelial Na channel (ENaC). Pendrin changes ENaC activity by changing both channel open probability (Po) and surface density (N), at least partly by altering luminal HCO3(-) and ATP concentration. Thus aldosterone and angiotensin II stimulate pendrin expression and function, which stimulates ENaC activity, thereby contributing to the pressor response of these hormones. However, pendrin may modulate blood pressure partly through its extrarenal effects. For example, pendrin is expressed in the adrenal medulla, where it modulates catecholamine release. The increase in catecholamine release observed with pendrin gene ablation likely contributes to the increment in vascular contractile force observed in the pendrin null mouse. This review summarizes the signaling mechanisms that regulate pendrin abundance and function as well as the contribution of pendrin to distal nephron function.
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Affiliation(s)
- Susan M Wall
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; and Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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33
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Relative roles of principal and intercalated cells in the regulation of sodium balance and blood pressure. Curr Hypertens Rep 2016; 17:538. [PMID: 25794953 DOI: 10.1007/s11906-015-0538-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The kidney continuously adapts daily renal excretion of NaCl to match dietary intakes in order to maintain the NaCl content of the body, and keep vascular volume constant. Any situation that leads to NaCl retention favors a rise in blood pressure. The aldosterone-sensitive distal nephron, which contains two main types of cells, principal (PC) and intercalated (IC) cells, is an important site for the final regulation of urinary Na(+) excretion. Research over the past 20 years established a paradigm in which PCs are the exclusive site of Na(+) absorption while ICs are solely dedicated to acid-base transport. Recent studies have revealed the unexpected importance of ICs for NaCl reabsorption. Here, we review the mechanisms of Na(+) and Cl(-) transport in the aldosterone-sensitive distal nephron, with emphasis on the role of ICs in maintaining NaCl balance and normal blood pressure.
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Pavlov TS, Ilatovskaya DV, Palygin O, Levchenko V, Pochynyuk O, Staruschenko A. Implementing Patch Clamp and Live Fluorescence Microscopy to Monitor Functional Properties of Freshly Isolated PKD Epithelium. J Vis Exp 2015. [PMID: 26381526 DOI: 10.3791/53035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cyst initiation and expansion during polycystic kidney disease is a complex process characterized by abnormalities in tubular cell proliferation, luminal fluid accumulation and extracellular matrix formation. Activity of ion channels and intracellular calcium signaling are key physiologic parameters which determine functions of tubular epithelium. We developed a method suitable for real-time observation of ion channels activity with patch-clamp technique and registration of intracellular Ca2+ level in epithelial monolayers freshly isolated from renal cysts. PCK rats, a genetic model of autosomal recessive polycystic kidney disease (ARPKD), were used here for ex vivo analysis of ion channels and calcium flux. Described here is a detailed step-by-step procedure designed to isolate cystic monolayers and non-dilated tubules from PCK or normal Sprague Dawley (SD) rats, and monitor single channel activity and intracellular Ca2+ dynamics. This method does not require enzymatic processing and allows analysis in a native setting of freshly isolated epithelial monolayer. Moreover, this technique is very sensitive to intracellular calcium changes and generates high resolution images for precise measurements. Finally, isolated cystic epithelium can be further used for staining with antibodies or dyes, preparation of primary cultures and purification for various biochemical assays.
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Affiliation(s)
| | | | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin
| | | | - Oleh Pochynyuk
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston
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Franco M, Bautista-Pérez R, Pérez-Méndez O. Purinergic receptors in tubulointerstitial inflammatory cells: a pathophysiological mechanism of salt-sensitive hypertension. Acta Physiol (Oxf) 2015; 214:75-87. [PMID: 25683649 DOI: 10.1111/apha.12471] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 10/28/2014] [Accepted: 02/09/2015] [Indexed: 12/24/2022]
Abstract
Recent studies have suggested that both the tubulointerstitial inflammatory cells and the activation of purinergic receptors integrate common mechanisms that result in salt-sensitive hypertension. The basis of this hypothesis is that renal endothelial cells release ATP in response to shear stress in the setting of hypertension. It has been demonstrated that the over-expression and activation of the P2X7, P2Y12 and P2X1 receptors favour the elevation of blood pressure induced by high-salt intake. In addition, the release of interleukins and inflammatory mediators in the tubulointerstitial area appears to be related to the activation of these receptors. Renal vasoconstriction and tubulointerstitial injury develop as a result, which increase sodium reabsorption by epithelial cells. Consistent with these effects, the reduction of tubulointerstitial inflammation caused by immunosuppressants, such as mycophenolate mofetil, prevents the development of salt-sensitive hypertension. Also, P2X7-receptor knockout mice develop minor renal injury when hypertension is induced via the administration of deoxycorticosterone acetate and a high-salt diet. In the setting of angiotensin II-induced hypertension, which is an early stage in the development of salt-sensitive hypertension, an acute blockade with the specific, non-selective P2 antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid prevented the renal vasoconstriction induced by angiotensin II. In addition, it normalized glomerular haemodynamics and restored sodium excretion to control values. These findings suggest that chronic administration of P2 purinergic antagonists may prevent the deleterious effects of purinergic receptors during the development of salt-sensitive hypertension.
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Affiliation(s)
- M. Franco
- Renal Physiopathology Laboratory; Department of Nephrology; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
| | - R. Bautista-Pérez
- Renal Physiopathology Laboratory; Department of Nephrology; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
- Molecular Biology Department; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
| | - O. Pérez-Méndez
- Molecular Biology Department; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
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Zhang Y, Robson SC, Morris KL, Heiney KM, Dwyer KM, Kishore BK, Ecelbarger CM. Impaired natriuretic response to high-NaCl diet plus aldosterone infusion in mice overexpressing human CD39, an ectonucleotidase (NTPDase1). Am J Physiol Renal Physiol 2015; 308:F1398-408. [PMID: 25877509 DOI: 10.1152/ajprenal.00125.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/09/2015] [Indexed: 01/14/2023] Open
Abstract
Extracellular nucleotides acting through P2 receptors facilitate natriuresis. To define how purinergic mechanisms are involved in sodium homeostasis, we used transgenic (TG) mice that globally overexpress human CD39 (hCD39, NTPDase1), an ectonucleotidase that hydrolyzes extracellular ATP/ADP to AMP, resulting in an altered extracellular purine profile. On a high-sodium diet (HSD, 3.5% Na(+)), urine volume and serum sodium were significantly higher in TG mice but sodium excretion was unaltered. Furthermore, TG mice showed an attenuated fall in urine aldosterone with HSD. Western blot analysis revealed significantly lower densities (∼40%) of the β-subunit of the epithelial sodium channel (ENaC) in medulla, and the major band (85-kDa) of γ-ENaC in TG mice cortex. To evaluate aldosterone-independent differences, in a second experiment, aldosterone was clamped by osmotic minipump at 20 μg/day, and mice were fed either an HSD or a low-sodium diet (LSD, 0.03% Na(+)). Here, no differences in urine volume or osmolality, or serum aldosterone were found, but TG mice showed a modest, yet significant impairment in late natriuresis (days 3 and 4). Several major sodium transporters or channel subunits were differentially expressed between the genotypes. HSD caused a downregulation of Na-Cl cotransporter (NCC) in both genotypes; and had higher cortical levels of NCC, Na-K-ATPase (α-1 subunit), and α- and γ-ENaC. The Na-K-2Cl cotransporter (NKCC2) was downregulated by HSD in wild-type mice, but it increased in TG mice. In summary, our data support the concept that extracellular nucleotides facilitate natriuresis; they also reveal an aldosterone-independent downregulation of major renal sodium transporters and channel subunits by purinergic signaling.
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Affiliation(s)
- Yue Zhang
- Nephrology Research, Department of Veterans Administration Salt Lake City Health Care System, Salt Lake City, Utah; Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah
| | - Simon C Robson
- Transplant Institute and Gastroenterology Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Kaiya L Morris
- Nephrology Research, Department of Veterans Administration Salt Lake City Health Care System, Salt Lake City, Utah; Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah
| | - Kristina M Heiney
- Nephrology Research, Department of Veterans Administration Salt Lake City Health Care System, Salt Lake City, Utah; Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah
| | - Karen M Dwyer
- Immunology Research Center, Department of Medicine, University of Melbourne, St. Vincent's Hospital, Fitzroy, Australia
| | - Bellamkonda K Kishore
- Nephrology Research, Department of Veterans Administration Salt Lake City Health Care System, Salt Lake City, Utah; Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah; Center on Aging, University of Utah Health Sciences Center, Salt Lake City, Utah;
| | - Carolyn M Ecelbarger
- Department of Medicine, Georgetown University, Washington, DC; and Center for the Study of Sex Differences in Health, Aging, and Disease, Georgetown University, Washington, District of Columbia
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Van Beusecum J, Inscho EW. Regulation of renal function and blood pressure control by P2 purinoceptors in the kidney. Curr Opin Pharmacol 2015; 21:82-8. [PMID: 25616035 PMCID: PMC5515225 DOI: 10.1016/j.coph.2015.01.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 12/24/2014] [Accepted: 01/05/2015] [Indexed: 12/11/2022]
Abstract
Kidneys are important regulators of extracellular fluid volume (ECFV) homeostasis. ECFV is a key regulatory component of long-term blood pressure control influenced by controlling tubular sodium transport. In recent decades, renal P2 purinoceptors (P2 receptors) have come to the forefront as a mechanism for regulating ECFV. P2 receptors are broadly distributed in renal tubular and vascular elements where they confer segmental control of renal vascular resistance, autoregulation, and tubular reabsorption. Activation or impairment of renal P2 purinoceptors is implicated in the regulating blood pressure or causing renal pathologies including hypertension. In this brief review, we discuss the role of renal vascular and tubular P2 purinoceptors in the regulation of renal hemodynamics, maintenance of ECFV, regulation of sodium reabsorption and the control of blood pressure.
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Affiliation(s)
- Justin Van Beusecum
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Edward W Inscho
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Control of ENaC-mediated sodium reabsorption in the distal nephron by Bradykinin. VITAMINS AND HORMONES 2015. [PMID: 25817868 DOI: 10.1016/bs.vh.2014.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Kinins, such as Bradykinin (BK), are peptide hormones of the kallikrein-kinin system. Apart from being a vasodilator, BK also increases urinary sodium excretion to reduce systemic blood pressure. It is becoming appreciated that BK modulates function of the epithelial Na(+) channel in the distal part of the renal nephron to affect tubular sodium reabsorption. In this chapter, we outline the molecular details, as well as discuss the physiological relevance of this regulation for the whole organism sodium homeostasis and setting chronic blood pressure.
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Abstract
The amiloride-sensitive epithelial Na(+) channel (ENaC) is a key player in the regulation of Na(+) homeostasis. Its functional activity is under continuous control by a variety of signaling molecules, including bioactive peptides of endothelin family. Since ENaC dysfunction is causative for disturbances in total body Na(+) levels associated with the abnormal regulation of blood volume, blood pressure, and lung fluid balance, uncovering the molecular mechanisms of inhibitory modulation or inappropriate activation of ENaC is crucial for the successful treatment of a variety of human diseases including hypertension. The precise regulation of ENaC is particularly important for normal Na(+) and fluid homeostasis in organs where endothelins are known to act: the kidneys, lung, and colon. Inhibition of ENaC by endothelin-1 (ET-1) has been established in renal cells, and several molecular mechanisms of inhibition of ENaC by ET-1 are proposed and will be reviewed in this chapter.
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Affiliation(s)
- Andrey Sorokin
- Division of Nephrology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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40
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Mamenko M, Zaika O, Boukelmoune N, O'Neil RG, Pochynyuk O. Deciphering physiological role of the mechanosensitive TRPV4 channel in the distal nephron. Am J Physiol Renal Physiol 2015; 308:F275-86. [PMID: 25503733 PMCID: PMC4329491 DOI: 10.1152/ajprenal.00485.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/08/2014] [Indexed: 12/14/2022] Open
Abstract
Long-standing experimental evidence suggests that epithelial cells in the renal tubule are able to sense osmotic and pressure gradients caused by alterations in ultrafiltrate flow by elevating intracellular Ca(2+) concentration. These responses are viewed as critical regulators of a variety of processes ranging from transport of water and solutes to cellular growth and differentiation. A loss in the ability to sense mechanical stimuli has been implicated in numerous pathologies associated with systemic imbalance of electrolytes and to the development of polycystic kidney disease. The molecular mechanisms conferring mechanosensitive properties to epithelial tubular cells involve activation of transient receptor potential (TRP) channels, such as TRPV4, allowing direct Ca(2+) influx to increase intracellular Ca(2+) concentration. In this review, we critically analyze the current evidence about signaling determinants of TRPV4 activation by luminal flow in the distal nephron and discuss how dysfunction of this mechanism contributes to the progression of polycystic kidney disease. We also review the physiological relevance of TRPV4-based mechanosensitivity in controlling flow-dependent K(+) secretion in the distal renal tubule.
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Affiliation(s)
- M Mamenko
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas
| | - O Zaika
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas
| | - N Boukelmoune
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas
| | - R G O'Neil
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas
| | - O Pochynyuk
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas
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41
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Pandit MM, Inscho EW, Zhang S, Seki T, Rohatgi R, Gusella L, Kishore B, Kohan DE. Flow regulation of endothelin-1 production in the inner medullary collecting duct. Am J Physiol Renal Physiol 2015; 308:F541-52. [PMID: 25587122 DOI: 10.1152/ajprenal.00456.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Collecting duct-derived endothelin (ET)-1 is an autocrine inhibitor of Na(+) and water reabsorption; its deficiency causes hypertension and water retention. Extracellular fluid volume expansion increases collecting duct ET-1, thereby promoting natriuresis and diuresis; however, how this coupling between volume expansion and collecting duct ET-1 occurs is incompletely understood. One possibility is that volume expansion increases tubular fluid flow. To investigate this, cultured IMCD3 cells were subjected to static or flow conditions. Exposure to a shear stress of 2 dyn/cm(2) for 2 h increased ET-1 mRNA content by ∼2.3-fold. Absence of perfusate Ca(2+), chelation of intracellular Ca(2+), or inhibition of Ca(2+) signaling (calmodulin, Ca(2+)/calmodulin-dependent kinase, calcineurin, PKC, or phospholipase C) prevented the flow response. Evaluation of possible flow-activated Ca(2+) entry pathways revealed no role for transient receptor potential (TRP)C3, TRPC6, and TRPV4; however, cells with TRPP2 (polycystin-2) knockdown had no ET-1 flow response. Flow increased intracellular Ca(2+) was blunted in TRPP2 knockdown cells. Nonspecific blockade of P2 receptors, as well as specific inhibition of P2X7 and P2Y2 receptors, prevented the ET-1 flow response. The ET-1 flow response was not affected by inhibition of either epithelial Na(+) channels or the mitochondrial Na(+)/Ca(2+) exchanger. Taken together, these findings provide evidence that in IMCD3 cells, flow, via polycystin-2 and P2 receptors, engages Ca(2+)-dependent signaling pathways that stimulate ET-1 synthesis.
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Affiliation(s)
- Meghana M Pandit
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah; Department of Pharmaceutics and Pharmaceutical Chemistry, Salt Lake City, Utah
| | | | - Shali Zhang
- University of Alabama at Birmingham, Birmingham, Alabama
| | - Tsugio Seki
- Department of Medical Education, California Northstate University, Elk Grove, California
| | - Rajeev Rohatgi
- Department of Medicine, James J. Peter Veterans Affairs Medical Center, Bronx, New York; Department of Medicine and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Luca Gusella
- Department of Medicine, James J. Peter Veterans Affairs Medical Center, Bronx, New York; Department of Medicine and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Bellamkonda Kishore
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah; Salt Lake Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah; Department of Pharmaceutics and Pharmaceutical Chemistry, Salt Lake City, Utah; Salt Lake Veterans Affairs Medical Center, Salt Lake City, Utah
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Pearce D, Soundararajan R, Trimpert C, Kashlan OB, Deen PM, Kohan DE. Collecting duct principal cell transport processes and their regulation. Clin J Am Soc Nephrol 2015; 10:135-46. [PMID: 24875192 PMCID: PMC4284417 DOI: 10.2215/cjn.05760513] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The principal cell of the kidney collecting duct is one of the most highly regulated epithelial cell types in vertebrates. The effects of hormonal, autocrine, and paracrine factors to regulate principal cell transport processes are central to the maintenance of fluid and electrolyte balance in the face of wide variations in food and water intake. In marked contrast with the epithelial cells lining the proximal tubule, the collecting duct is electrically tight, and ion and osmotic gradients can be very high. The central role of principal cells in salt and water transport is reflected by their defining transporters-the epithelial Na(+) channel (ENaC), the renal outer medullary K(+) channel, and the aquaporin 2 (AQP2) water channel. The coordinated regulation of ENaC by aldosterone, and AQP2 by arginine vasopressin (AVP) in principal cells is essential for the control of plasma Na(+) and K(+) concentrations, extracellular fluid volume, and BP. In addition to these essential hormones, additional neuronal, physical, and chemical factors influence Na(+), K(+), and water homeostasis. Notably, a variety of secreted paracrine and autocrine agents such as bradykinin, ATP, endothelin, nitric oxide, and prostaglandin E2 counterbalance and limit the natriferic effects of aldosterone and the water-retaining effects of AVP. Considerable recent progress has improved our understanding of the transporters, receptors, second messengers, and signaling events that mediate principal cell responses to changing environments in health and disease. This review primarily addresses the structure and function of the key transporters and the complex interplay of regulatory factors that modulate principal cell ion and water transport.
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Affiliation(s)
- David Pearce
- Division of Nephrology, Department of Medicine, University of California, San Francisco, California
| | - Rama Soundararajan
- Department of Translational Molecular Pathology, MD Anderson Cancer Center, Houston, Texas
| | - Christiane Trimpert
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ossama B. Kashlan
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Peter M.T. Deen
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Donald E. Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah
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Bruijn PIA, Bleich M, Praetorius HA, Leipziger J. P2X receptors trigger intracellular alkalization in isolated perfused mouse medullary thick ascending limb. Acta Physiol (Oxf) 2015; 213:277-84. [PMID: 25362991 PMCID: PMC4374443 DOI: 10.1111/apha.12417] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 09/23/2014] [Accepted: 10/24/2014] [Indexed: 02/03/2023]
Abstract
Aims Extracellular ATP is an important regulator of renal tubular transport. Recently, we found that basolateral ATP markedly inhibits Na+ and Cl− absorption in mouse medullary thick ascending limb (mTAL) via a P2X receptor. The underlying mechanism that mediates this ATP-dependent transport inhibition in mTAL is, however, unclear. The renal outer medullary K+ channel (ROMK) is sensitive to intracellular pH where a reduction leads to closing of ROMK. We speculated that P2X receptor stimulation in the TAL could lead to changes in pHi, leading to a reduction in NaCl transport. Methods To test this hypothesis, we measured pHi in single perfused mouse mTALs using the fluorescent ratiometric dye 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethylester. Results Interestingly, basolateral ATP (100 μm) caused a prominent, reversible intracellular alkalization of mTAL, with an average pHi increase of 0.14 ± 0.02 (n = 14). This was completely abolished by the P2X receptor antagonist periodate-oxidized ATP (50 μm). The P2X receptor-mediated intracellular alkalization required the activity of the apical Na+/H+ exchanger (NHE3). Typically, Gq-coupled receptors cause a significant acidification of tubular epithelial cells, which was confirmed in this study, by P2Y2 and Ca2+ sensing receptor stimulation. Conclusion This study reports that stimulation of basolateral P2X receptors causes a substantial intracellular alkalization in the isolated perfused mouse mTAL. This intracellular alkalization is mediated through an increased apical NHE3 activity, similar to what we previously observed when tubular transport is inhibited with furosemide. This increased NHE3 activity causes H+ secretion in the mTAL and provides further support that the TAL is a site of urinary acidification.
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Affiliation(s)
- P. I. A. Bruijn
- Department of Biomedicine, Physiology and Biophysics Aarhus University Aarhus C Denmark
| | - M. Bleich
- Institute of Physiology Christian‐Albrechts‐University Kiel Germany
| | - H. A. Praetorius
- Department of Biomedicine, Physiology and Biophysics Aarhus University Aarhus C Denmark
| | - J. Leipziger
- Department of Biomedicine, Physiology and Biophysics Aarhus University Aarhus C Denmark
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Impaired epithelial Na+ channel activity contributes to cystogenesis and development of autosomal recessive polycystic kidney disease in PCK rats. Pediatr Res 2015; 77:64-9. [PMID: 25279988 PMCID: PMC4268054 DOI: 10.1038/pr.2014.145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 07/16/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND Autosomal recessive polycystic kidney disease is a genetic disorder characterized by the development of renal cysts of tubular epithelial cell origin. Epithelial Na(+) channel (ENaC) is responsible for sodium reabsorption in the aldosterone-sensitive distal nephron. Here, we investigated the ENaC expression and activity in cystic tissue taken from rats with autosomal recessive polycystic kidney disease. METHODS Polycystic kidney (PCK) rats were treated with the selective ENaC inhibitor benzamil given in the drinking water, and after 4 or 12 wk, the severity of morphological malformations in the kidneys was assessed. ENaC and aquaporin-2 expression and ENaC activity were tested with immunohistochemistry and patch-clamp electrophysiology, respectively. RESULTS Treatment with benzamil exacerbated development of cysts compared with the vehicle-treated animals. In contrast, the 12 wk of treatment with the loop diuretic furosemide had no effect on cystogenesis. Single-channel patch-clamp analysis revealed that ENaC activity in the freshly isolated cystic epithelium was significantly lower than that in the noncystic collecting ducts isolated from PCK or normal Sprague-Dawley rats. Immunohistochemical analysis confirmed that β-ENaC and aquaporin-2 expressions in cysts are decreased compared with nondilated tubules from PCK rat kidneys. CONCLUSION We demonstrated that cystic epithelium exhibits low ENaC activity and this phenomenon can contribute to cyst progression.
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Mironova E, Boiko N, Bugaj V, Kucher V, Stockand JD. Regulation of Na+ excretion and arterial blood pressure by purinergic signalling intrinsic to the distal nephron: consequences and mechanisms. Acta Physiol (Oxf) 2015; 213:213-21. [PMID: 25154328 DOI: 10.1111/apha.12372] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/14/2014] [Accepted: 08/21/2014] [Indexed: 12/13/2022]
Abstract
Discretionary control of Na(+) excretion is a key component of the regulation of arterial blood pressure in mammals. Sodium excretion is fine-tuned in the aldosterone-sensitive distal nephron by the activity of the epithelial Na(+) channel (ENaC). Here, ENaC functions as a final effector of the renin-angiotensin-aldosterone system (RAAS) during negative feedback control of blood pressure. Mutations affecting ENaC activity and abnormal regulation of this channel affect blood pressure through pathological changes to Na(+) excretion. Recent evidence demonstrates that powerful signalling pathways function in parallel with the RAAS to modulate ENaC activity and blood pressure. An inclusive paradigm is emerging with respect to regulation of blood pressure where ENaC serves as a critical point of convergence for several important signalling systems that affect renal Na(+) excretion. A robust inhibitory purinergic signalling system intrinsic to the distal nephron dynamically regulates ENaC through paracrine ATP signalling via the metabotropic P2Y2 purinergic receptor to properly match urinary Na(+) excretion to dietary Na(+) intake. This enables blood pressure to be maintained within a normal range despite broad changes in dietary Na(+) consumption. Loss of purinergic inhibition of ENaC increases blood pressure by causing inappropriate Na(+) excretion. In contrast, stimulation of the P2Y2 receptor promotes natriuresis and a decrease in blood pressure. Such observations identify purinergic signalling in the distal nephron as possibly causative, when dysfunctional, for certain forms of elevated blood pressure, and as a possible therapeutic target for the treatment of elevated blood pressure particularly that associated with salt sensitivity.
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Affiliation(s)
- E. Mironova
- Department of Physiology; University of Texas Health Science Center; San Antonio TX USA
| | - N. Boiko
- Department of Physiology; University of Texas Health Science Center; San Antonio TX USA
| | - V. Bugaj
- Department of Physiology; University of Texas Health Science Center; San Antonio TX USA
| | - V. Kucher
- Department of Physiology; University of Texas Health Science Center; San Antonio TX USA
| | - J. D. Stockand
- Department of Physiology; University of Texas Health Science Center; San Antonio TX USA
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Menzies RI, Unwin RJ, Bailey MA. Renal P2 receptors and hypertension. Acta Physiol (Oxf) 2015; 213:232-41. [PMID: 25345692 DOI: 10.1111/apha.12412] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 09/23/2014] [Accepted: 10/17/2014] [Indexed: 12/11/2022]
Abstract
The regulation of extracellular fluid volume is a key component of blood pressure homeostasis. Long-term blood pressure is stabilized by the acute pressure natriuresis response by which changes in renal perfusion pressure evoke corresponding changes in renal sodium excretion. A wealth of experimental evidence suggests that a defect in the pressure natriuresis response contributes to the development and maintenance of hypertension. The mechanisms underlying the relationship between renal perfusion pressure and sodium excretion are incompletely understood. Increased blood flow through the vasa recta increases renal interstitial hydrostatic pressure, thereby reducing the driving force for transepithelial sodium reabsorption. Paracrine signalling also contributes to the overall natriuretic response by inhibiting tubular sodium reabsorption in several nephron segments. In this brief review, we discuss the role of purinergic signalling in the renal control of blood pressure. ATP is released from renal tubule and vascular cells in response to increased flow and can activate P2 receptor subtypes expressed in both epithelial and vascular endothelial/smooth muscle cells. In concert, these effects integrate the vascular and tubular responses to increased perfusion pressure and targeting P2 receptors, particularly P2X7, may prove beneficial for treatment of hypertension.
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Affiliation(s)
- R. I. Menzies
- University/British Heart Foundation; Centre for Cardiovascular Science; The University of Edinburgh; Edinburgh UK
- MRC Institute for Genetics and Molecular Medicine; The University of Edinburgh; Edinburgh UK
| | - R. J. Unwin
- UCL Centre for Nephrology; University College London; London UK
| | - M. A. Bailey
- University/British Heart Foundation; Centre for Cardiovascular Science; The University of Edinburgh; Edinburgh UK
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Solini A, Usuelli V, Fiorina P. The dark side of extracellular ATP in kidney diseases. J Am Soc Nephrol 2014; 26:1007-16. [PMID: 25452669 DOI: 10.1681/asn.2014070721] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Intracellular ATP is the most vital source of cellular energy for biologic systems, whereas extracellular ATP is a multifaceted mediator of several cell functions via its interaction, in an autocrine or paracrine manner, with P2 purinergic receptors expressed on the cell surface. These ionotropic and metabotropic P2 purinergic receptors modulate a variety of physiologic events upon the maintenance of a highly sensitive "set point," the derangement of which may lead to the development of key pathogenic mechanisms during acute and chronic diseases. Growing evidence suggests that extracellular ATP signaling via P2 purinergic receptors may be involved in different renal pathologic conditions. For these reasons, investigators and pharmaceutical companies are actively exploring novel strategies to antagonize or block these receptors with the goal of reducing extracellular ATP production or accelerating extracellular ATP clearance. Targeting extracellular ATP signaling, particularly through the P2X7 receptor, has considerable translational potential, given that novel P2X7-receptor inhibitors are already available for clinical use (e.g., CE224,535, AZD9056, and GSK1482160). This review summarizes the current evidence regarding the involvement of extracellular ATP and its P2 purinergic receptor-mediated signaling in physiologic and pathologic processes in the kidney; potential therapeutic options targeting extracellular ATP purinergic receptors are analyzed as well.
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Affiliation(s)
- Anna Solini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Vera Usuelli
- Division of Transplant Medicine, San Raffaele Hospital, Milan, Italy; and
| | - Paolo Fiorina
- Division of Transplant Medicine, San Raffaele Hospital, Milan, Italy; and Nephrology Division, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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48
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Svenningsen P, Nielsen MR, Marcussen N, Walter S, Jensen BL. TMEM16A is a Ca(2+) -activated Cl(-) channel expressed in the renal collecting duct. Acta Physiol (Oxf) 2014; 212:166-74. [PMID: 24913262 DOI: 10.1111/apha.12323] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 05/16/2014] [Accepted: 06/03/2014] [Indexed: 01/10/2023]
Abstract
AIM In the renal collecting ducts, ATP stimulates a Ca(2+) -activated chloride current. The identity of the channel responsible for the current under physiological conditions is not known and it was hypothesized that TMEM16a is a relevant candidate in the renal collecting duct. METHODS The cortical collecting duct cell line M-1 was used as a model of the collecting duct. The ATP induced Ca(2+) signalling was imaged in cells loaded with Ca(2+) -sensitive fluorescent probes using confocal laser-scanning fluorescence microscopy. Chloride current was determined by mounting M-1 cell layers in Ussing chamber. The expression of TMEM16a in human kidney was tested by immunohistochemistry. RESULTS M-1 cells displayed a transient increase in intracellular Ca(2+) concentration in response to 100 nm ATP. This response was completely blocked by addition of 100 μm suramin, indicating that ATP signals through purinergic P2 receptors. Apical addition of 100 nm ATP induced a Cl(-) current, which was blocked by suramin, DPC and the cysteine-modifying compound MTSET. M-1 cells were found to express TMEM16a at the mRNA and protein level. Functionally, it was found that knock-down of TMEM16a expression in M-1 cells inhibited the ATP induced Cl(-) -current. In human and mouse kidney sections, TMEM16a protein expression was localized to the collecting duct, and TMEM16a was found to be excreted in human urinary exosomes. CONCLUSION TMEM16a is a Ca(2+) -activated Cl(-) channel expressed in the collecting ducts.
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Affiliation(s)
- P. Svenningsen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - M. R. Nielsen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - N. Marcussen
- Department of Clinical Pathology; Odense University Hospital; Odense Denmark
| | - S. Walter
- Department of Urology; Odense University Hospital; Odense Denmark
| | - B. L. Jensen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
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Berrout J, Mamenko M, Zaika OL, Chen L, Zang W, Pochynyuk O, O'Neil RG. Emerging role of the calcium-activated, small conductance, SK3 K+ channel in distal tubule function: regulation by TRPV4. PLoS One 2014; 9:e95149. [PMID: 24762817 PMCID: PMC3999037 DOI: 10.1371/journal.pone.0095149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 03/24/2014] [Indexed: 12/24/2022] Open
Abstract
The Ca2+-activated, maxi-K (BK) K+ channel, with low Ca2+-binding affinity, is expressed in the distal tubule of the nephron and contributes to flow-dependent K+ secretion. In the present study we demonstrate that the Ca2+-activated, SK3 (KCa2.3) K+ channel, with high Ca2+-binding affinity, is also expressed in the mouse kidney (RT-PCR, immunoblots). Immunohistochemical evaluations using tubule specific markers demonstrate significant expression of SK3 in the distal tubule and the entire collecting duct system, including the connecting tubule (CNT) and cortical collecting duct (CCD). In CNT and CCD, main sites for K+ secretion, the highest levels of expression were along the apical (luminal) cell membranes, including for both principal cells (PCs) and intercalated cells (ICs), posturing the channel for Ca2+-dependent K+ secretion. Fluorescent assessment of cell membrane potential in native, split-opened CCD, demonstrated that selective activation of the Ca2+-permeable TRPV4 channel, thereby inducing Ca2+ influx and elevating intracellular Ca2+ levels, activated both the SK3 channel and the BK channel leading to hyperpolarization of the cell membrane. The hyperpolarization response was decreased to a similar extent by either inhibition of SK3 channel with the selective SK antagonist, apamin, or by inhibition of the BK channel with the selective antagonist, iberiotoxin (IbTX). Addition of both inhibitors produced a further depolarization, indicating cooperative effects of the two channels on Vm. It is concluded that SK3 is functionally expressed in the distal nephron and collecting ducts where induction of TRPV4-mediated Ca2+ influx, leading to elevated intracellular Ca2+ levels, activates this high Ca2+-affinity K+ channel. Further, with sites of expression localized to the apical cell membrane, especially in the CNT and CCD, SK3 is poised to be a key pathway for Ca2+-dependent regulation of membrane potential and K+ secretion.
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Affiliation(s)
- Jonathan Berrout
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Mykola Mamenko
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Oleg L. Zaika
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Lihe Chen
- Department of Internal Medicine-Division of Renal Diseases and Hypertension, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Wenzheng Zang
- Department of Internal Medicine-Division of Renal Diseases and Hypertension, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Oleh Pochynyuk
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Roger G. O'Neil
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
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50
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Burnstock G, Evans LC, Bailey MA. Purinergic signalling in the kidney in health and disease. Purinergic Signal 2014; 10:71-101. [PMID: 24265071 PMCID: PMC3944043 DOI: 10.1007/s11302-013-9400-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 12/21/2022] Open
Abstract
The involvement of purinergic signalling in kidney physiology and pathophysiology is rapidly gaining recognition and this is a comprehensive review of early and recent publications in the field. Purinergic signalling involvement is described in several important intrarenal regulatory mechanisms, including tuboglomerular feedback, the autoregulatory response of the glomerular and extraglomerular microcirculation and the control of renin release. Furthermore, purinergic signalling influences water and electrolyte transport in all segments of the renal tubule. Reports about purine- and pyrimidine-mediated actions in diseases of the kidney, including polycystic kidney disease, nephritis, diabetes, hypertension and nephrotoxicant injury are covered and possible purinergic therapeutic strategies discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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