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Pyrshev K, Stavniichuk A, Tomilin VN, Khayyat NH, Ren G, Kordysh M, Zaika O, Mamenko M, Pochynyuk O. TRPV4 functional status in cystic cells regulates cystogenesis in autosomal recessive polycystic kidney disease during variations in dietary potassium. Physiol Rep 2023; 11:e15641. [PMID: 36946001 PMCID: PMC10031299 DOI: 10.14814/phy2.15641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/23/2023] Open
Abstract
Mechanosensitive TRPV4 channel plays a dominant role in maintaining [Ca2+ ]i homeostasis and flow-sensitive [Ca2+ ]i signaling in the renal tubule. Polycystic kidney disease (PKD) manifests as progressive cyst growth due to cAMP-dependent fluid secretion along with deficient mechanosensitivity and impaired TRPV4 activity. Here, we tested how regulation of renal TRPV4 function by dietary K+ intake modulates the rate of cystogenesis and mechanosensitive [Ca2+ ]i signaling in cystic cells of PCK453 rats, a homologous model of human autosomal recessive PKD (ARPKD). One month treatment with both high KCl (5% K+ ) and KB/C (5% K+ with bicarbonate/citrate) diets significantly increased TRPV4 levels when compared to control (0.9% K+ ). High KCl diet caused an increased TRPV4-dependent Ca2+ influx, and partial restoration of mechanosensitivity in freshly isolated monolayers of cystic cells. Unexpectedly, high KB/C diet induced an opposite effect by reducing TRPV4 activity and worsening [Ca2+ ]i homeostasis. Importantly, high KCl diet decreased cAMP, whereas high KB/C diet further increased cAMP levels in cystic cells (assessed as AQP2 distribution). At the systemic level, high KCl diet fed PCK453 rats had significantly lower kidney-to-bodyweight ratio and reduced cystic area. These beneficial effects were negated by a concomitant administration of an orally active TRPV4 antagonist, GSK2193874, resulting in greater kidney weight, accelerated cystogenesis, and augmented renal injury. High KB/C diet also exacerbated renal manifestations of ARPKD, consistent with deficient TRPV4 activity in cystic cells. Overall, we demonstrate that TRPV4 channel activity negatively regulates cAMP levels in cystic cells thus attenuating (high activity) or accelerating (low activity) ARPKD progression.
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Affiliation(s)
- Kyrylo Pyrshev
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Anna Stavniichuk
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Viktor N. Tomilin
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Guohui Ren
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Mariya Kordysh
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Oleg Zaika
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Mykola Mamenko
- Department of PhysiologyAugusta UniversityAugustaGeorgiaUSA
| | - Oleh Pochynyuk
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
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Hagmann H, Khayyat NH, Matin M, Oezel C, Chen H, Schauss A, Schell C, Benzing T, Dryer S, Brinkkoetter PT. Capsazepine (CPZ) Inhibits TRPC6 Conductance and Is Protective in Adriamycin-Induced Nephropathy and Diabetic Glomerulopathy. Cells 2023; 12:cells12020271. [PMID: 36672207 PMCID: PMC9856956 DOI: 10.3390/cells12020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/15/2022] [Accepted: 01/05/2023] [Indexed: 01/12/2023] Open
Abstract
Reactive oxygen species (ROS), which excessively arise in diabetes and systemic inflammatory diseases, modify cellular lipids and cellular lipid composition leading to altered biophysical properties of cellular membranes. The impact of lipid peroxidation on transmembrane signaling routes is not yet well studied. The canonical transient receptor potential channel 6 (TRPC6) is implicated in the pathogenesis of several forms of glomerular diseases. TRPC6 is sensitive to membrane stretch and relies on a distinct lipid environment. This study investigates the effect of oxidative alterations to plasma membrane lipids on TRPC6 activity and the function of the glomerular filter. Knockout of the anti-oxidative, lipid modifying enzyme paraoxonase 2 (PON2) leads to altered biophysical properties of glomerular epithelial cells, which are called podocytes. Cortical stiffness, quantified by atomic force microscopy, was largely increased in PON2-deficient cultured podocytes. PON2 deficiency markedly enhanced TRPC6 channel currents and channel recovery. Treatment with the amphiphilic substance capsazepine in micromolar doses reduced cortical stiffness and abrogated TRPC6 conductance. In in vivo studies, capsazepine reduced the glomerular phenotype in the model of adriamycin-induced nephropathy in PON2 knockout mice and wildtype littermates. In diabetic AKITA mice, the progression of albuminuria and diabetic kidney disease was delayed. In summary, we provide evidence that the modification of membrane characteristics affects TRPC6 signaling. These results could spur future research to investigate modification of the direct lipid environment of TRPC6 as a future therapeutic strategy in glomerular disease.
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Affiliation(s)
- Henning Hagmann
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
- Correspondence:
| | | | - Mahsa Matin
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
| | - Cem Oezel
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
| | - He Chen
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
| | - Astrid Schauss
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), 50931 Cologne, Germany
| | - Christoph Schell
- Institute of Surgical Pathology, Faculty of Medicine, University Medical Center Freiburg, 79106 Freiburg, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), 50931 Cologne, Germany
- Systems Biology of Ageing Cologne (Sybacol), 50931 Cologne, Germany
| | - Stuart Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, TX 77204, USA
| | - Paul T. Brinkkoetter
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
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3
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Hagmann H, Khayyat NH, Oezel C, Papadakis A, Kuczkowski A, Benzing T, Gulbins E, Dryer S, Brinkkoetter PT. Paraoxonase 2 (PON2) Deficiency Reproduces Lipid Alterations of Diabetic and Inflammatory Glomerular Disease and Affects TRPC6 Signaling. Cells 2022; 11:cells11223625. [PMID: 36429053 PMCID: PMC9688324 DOI: 10.3390/cells11223625] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/31/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Diabetes and inflammatory diseases are associated with an altered cellular lipid composition due to lipid peroxidation. The pathogenic potential of these lipid alterations in glomerular kidney diseases remains largely obscure as suitable cell culture and animal models are lacking. In glomerular disease, a loss of terminally differentiated glomerular epithelial cells called podocytes refers to irreversible damage. Podocytes are characterized by a complex ramified cellular architecture and highly active transmembrane signaling. Alterations in lipid composition in states of disease have been described in podocytes but the pathophysiologic mechanisms mediating podocyte damage are unclear. In this study, we employ a genetic deletion of the anti-oxidative, lipid-modifying paraoxonase 2 enzyme (PON2) as a model to study altered cellular lipid composition and its effects on cellular signaling in glomerular disease. PON2 deficiency reproduces features of an altered lipid composition of glomerular disease, characterized by an increase in ceramides and cholesterol. PON2 knockout mice are more susceptible to glomerular damage in models of aggravated oxidative stress such as adriamycin-induced nephropathy. Voltage clamp experiments in cultured podocytes reveal a largely increased TRPC6 conductance after a membrane stretch in PON2 deficiency. Correspondingly, a concomitant knockout of TRPC6 and PON2 partially rescues the aggravated glomerular phenotype of a PON2 knockout in the adriamycin model. This study establishes PON2 deficiency as a model to investigate the pathophysiologic mechanisms of podocyte dysfunction related to alterations in the lipid composition, as seen in diabetic and inflammatory glomerular disease. Expanding the knowledge on these routes and options of intervention could lead to novel treatment strategies for glomerular disease.
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Affiliation(s)
- Henning Hagmann
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
- Correspondence:
| | | | - Cem Oezel
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
| | - Antonios Papadakis
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
- Institute for Genetics, Faculty of Mathematics and Natural Sciences, University of Cologne, 50931 Cologne, Germany
| | - Alexander Kuczkowski
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol), 50931 Cologne, Germany
| | - Erich Gulbins
- Department of Molecular Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany
| | - Stuart Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, TX 77204, USA
| | - Paul T. Brinkkoetter
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
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4
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Pyrshev K, Khayyat NH, Stavniichuk A, Tomilin VN, Zaika O, Ramkumar N, Pochynyuk O. ClC-K2 Cl - channel allows identification of A- and B-type of intercalated cells in split-opened collecting ducts. FASEB J 2022; 36:e22275. [PMID: 35349181 PMCID: PMC9014849 DOI: 10.1096/fj.202200160r] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/01/2022] [Accepted: 03/14/2022] [Indexed: 11/11/2022]
Abstract
The collecting duct is a highly adaptive terminal part of the nephron, which is essential for maintaining systemic homeostasis. Principal and intercalated cells perform different physiological tasks and exhibit distinctive morphology. However, acid-secreting A- and base secreting B-type of intercalated cells cannot be easily separated in functional studies. We used BCECF-sensitive intracellular pH (pHi ) measurements in split-opened collecting ducts followed by immunofluorescent microscopy in WT and intercalated cell-specific ClC-K2-/- mice to demonstrate that ClC-K2 inhibition enables to distinguish signals from A- and B-intercalated cells. We show that ClC-K2 Cl- channel is expressed on the basolateral side of intercalated cells, where it governs Cl- -dependent H+ /HCO3 - transport. ClC-K2 blocker, NPPB, caused acidification or alkalization in different subpopulations of intercalated cells in WT but not ClC-K2-/- mice. Immunofluorescent assessment of the same collecting ducts revealed that NPPB increased pHi in AE1-positive A-type and decreased pHi in pendrin-positive B-type of intercalated cells. Induction of metabolic acidosis led to a significantly augmented abundance and H+ secretion in A-type and decreased proton transport in B-type of intercalated cells, whereas metabolic alkalosis caused the opposite changes in intercalated cell function, but did not substantially change their relative abundance. Overall, we show that inhibition of ClC-K2 can be employed to discriminate between A- and B-type of intercalated cells in split-opened collecting duct preparations. We further demonstrate that this method can be used to independently monitor changes in the functional status and abundance of A- and B-type in response to systemic acid/base stimuli.
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Affiliation(s)
- Kyrylo Pyrshev
- Department of Integrative Biology and Pharmacology, the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Anna Stavniichuk
- Department of Integrative Biology and Pharmacology, the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Nirupama Ramkumar
- Division of Nephrology and Hypertension, University of Utah Health, Salt Lake City, Utah, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, the University of Texas Health Science Center at Houston, Houston, Texas, USA
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5
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Tomilin VN, Pyrshev K, Stavniichuk A, Hassanzadeh Khayyat N, Ren G, Zaika O, Khedr S, Staruschenko A, Mei FC, Cheng X, Pochynyuk O. Epac1-/- and Epac2-/- mice exhibit deficient epithelial Na+ channel regulation and impaired urinary Na+ conservation. JCI Insight 2021; 7:145653. [PMID: 34914636 PMCID: PMC8855822 DOI: 10.1172/jci.insight.145653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/15/2021] [Indexed: 12/03/2022] Open
Abstract
Exchange proteins directly activated by cAMP (Epacs) are abundantly expressed in the renal tubules. We used genetic and pharmacological tools in combination with balance, electrophysiological, and biochemical approaches to examine the role of Epac1 and Epac2 in renal sodium handling. We demonstrate that Epac1–/– and Epac2–/– mice exhibit a delayed anti-natriuresis to dietary sodium restriction despite augmented aldosterone levels. This was associated with a significantly lower response to the epithelial Na+ channel (ENaC) blocker amiloride, reduced ENaC activity in split-opened collecting ducts, and defective posttranslational processing of α and γENaC subunits in the KO mice fed with a Na+-deficient diet. Concomitant deletion of both isoforms led to a marginally greater natriuresis but further increased aldosterone levels. Epac2 blocker ESI-05 and Epac1&2 blocker ESI-09 decreased ENaC activity in Epac WT mice kept on the Na+-deficient diet but not on the regular diet. ESI-09 injections led to natriuresis in Epac WT mice on the Na+-deficient diet, which was caused by ENaC inhibition. In summary, our results demonstrate similar but nonredundant actions of Epac1 and Epac2 in stimulation of ENaC activity during variations in dietary salt intake. We speculate that inhibition of Epac signaling could be instrumental in treatment of hypertensive states associated with ENaC overactivation.
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Affiliation(s)
- Victor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Kyrylo Pyrshev
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Anna Stavniichuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Guohui Ren
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Sherif Khedr
- Department of Physiology, Medical College of Wisconsin, Milwuakee, United States of America
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwuakee, United States of America
| | - Fang C Mei
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Xiaodong Cheng
- The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
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Abstract
TRPC3 is a Ca2+-permeable cation channel commonly activated by the G-protein coupled receptors (GPCR) and mechanical distortion of the plasma membrane. TRPC3-mediated Ca2+ influx has been implicated in a variety of signaling processes in both excitable and non-excitable cells. Kidneys play a commanding role in maintaining whole-body homeostasis and setting blood pressure. TRPC3 is expressed abundantly in the renal vasculature and in epithelial cells, where it is well positioned to mediate signaling and transport functions in response to GPCR-dependent endocrine stimuli. In addition, TRPC3 could be activated by mechanical forces resulting from dynamic changes in the renal tubule fluid flow and osmolarity. This review critically analyzes the available published evidence of the physiological roles of TRPC3 in different parts of the kidney and describes the pathophysiological ramifications of TRPC3 ablation. We also speculate how this evidence could be further translated into the clinic.
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Affiliation(s)
- Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
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7
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Hassanzadeh Khayyat N, Tomilin V, Pyrshev K, Zaika O, Mei F, Cheng X, Pochynyuk O. Exchange Protein Directly Activated by cAMP Isoform 2 (Epac2) but Not Isoform 1 (Epac1) Is Critical for Renal Acid‐Base Handling. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Viktor Tomilin
- Department of Integrative Biology and PharmacologyMcGovern Medical School at UTHealthHoustonTX
| | - Kyrylo Pyrshev
- Department of Integrative Biology and PharmacologyMcGovern Medical School at UTHealthHoustonTX
| | - Oleg Zaika
- McGovern Medical School at UTHealthHoustonTX
| | - Fang Mei
- McGovern Medical School at UTHealthHoustonTX
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8
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Tomilin V, Pyrshev K, Hassanzadeh Khayyat N, Zaika O, Pochynyuk O. With‐No‐Lysine kinase ‐1 increases TRPV4 calcium channel activity in the collecting duct cells. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Kyrylo Pyrshev
- Integrative Biology and PharmacologyUTHSC at HoustonHoustonTX
| | | | - Oleg Zaika
- Integrative Biology and PharmacologyUTHSC at HoustonHoustonTX
| | - Oleh Pochynyuk
- Integrative Biology and PharmacologyUTHSC at HoustonHoustonTX
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9
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Hassanzadeh Khayyat N, Zaika O, Tomilin V, Pyrshev K, Pochynyuk O. Angiotensin II Stimulates Basolateral Conductance in Intercalated but Not Principal Cells of the Collecting Duct by Promoting Generation of Reactive Oxygen Species. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Oleg Zaika
- McGovern Medical School at UTHealthHoustonTX
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10
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Khayyat NH, Zaika O, Tomilin VN, Pyrshev K, Pochynyuk O. Angiotensin II increases activity of the ClC-K2 Cl - channel in collecting duct intercalated cells by stimulating production of reactive oxygen species. J Biol Chem 2021; 296:100347. [PMID: 33524393 PMCID: PMC7949157 DOI: 10.1016/j.jbc.2021.100347] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/21/2021] [Accepted: 01/25/2021] [Indexed: 01/11/2023] Open
Abstract
The renal collecting duct plays a critical role in setting urinary volume and composition, with principal cells transporting Na+ and K+ and intercalated cells mediating Cl- reabsorption. Published evidence implies Angiotensin II (Ang II) is a potent regulator of the collecting duct apical transport systems in response to systemic volume depletion. However, virtually nothing is known about Ang II actions on the basolateral conductance of principal and intercalated cells. Here, we combined macroscopic and single channel patch clamp recordings from freshly isolated mouse collecting ducts with biochemical and fluorescence methods to demonstrate an acute stimulation of the basolateral Cl- conductance and specifically the ClC-K2 Cl- channel by nanomolar Ang II concentrations in intercalated cells. In contrast, Ang II did not exhibit measurable effects on the basolateral conductance and on Kir4.1/5.1 potassium channel activity in principal cells. Although both Ang II receptors AT1 and AT2 are expressed in collecting duct cells, we show that AT1 receptors were essential for stimulatory actions of Ang II on ClC-K2. Moreover, AT1R-/- mice had decreased renal ClC-K2 expression. We further demonstrated that activation of NADPH oxidases is the major signaling pathway downstream of Ang II-AT1R that leads to stimulation of ClC-K2. Treatment of freshly isolated collecting ducts with Ang II led to production of reactive oxygen species on the same timescale as single channel ClC-K2 activation. Overall, we propose that Ang II-dependent regulation of ClC-K2 in intercalated cells is instrumental for stimulation of Cl- reabsorption by the collecting duct, particularly during hypovolemic states.
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Affiliation(s)
- Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Kyrylo Pyrshev
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA.
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11
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Zaidman NA, Tomilin VN, Hassanzadeh Khayyat N, Damarla M, Tidmore J, Capen DE, Brown D, Pochynyuk OM, Pluznick JL. Adhesion-GPCR Gpr116 (ADGRF5) expression inhibits renal acid secretion. Proc Natl Acad Sci U S A 2020; 117:26470-26481. [PMID: 33004624 PMCID: PMC7584995 DOI: 10.1073/pnas.2007620117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The diversity and near universal expression of G protein-coupled receptors (GPCR) reflects their involvement in most physiological processes. The GPCR superfamily is the largest in the human genome, and GPCRs are common pharmaceutical targets. Therefore, uncovering the function of understudied GPCRs provides a wealth of untapped therapeutic potential. We previously identified an adhesion-class GPCR, Gpr116, as one of the most abundant GPCRs in the kidney. Here, we show that Gpr116 is highly expressed in specialized acid-secreting A-intercalated cells (A-ICs) in the kidney using both imaging and functional studies, and we demonstrate in situ receptor activation using a synthetic agonist peptide unique to Gpr116. Kidney-specific knockout (KO) of Gpr116 caused a significant reduction in urine pH (i.e., acidification) accompanied by an increase in blood pH and a decrease in pCO2 compared to WT littermates. Additionally, immunogold electron microscopy shows a greater accumulation of V-ATPase proton pumps at the apical surface of A-ICs in KO mice compared to controls. Furthermore, pretreatment of split-open collecting ducts with the synthetic agonist peptide significantly inhibits proton flux in ICs. These data suggest a tonic inhibitory role for Gpr116 in the regulation of V-ATPase trafficking and urinary acidification. Thus, the absence of Gpr116 results in a primary excretion of acid in KO mouse urine, leading to mild metabolic alkalosis ("renal tubular alkalosis"). In conclusion, we have uncovered a significant role for Gpr116 in kidney physiology, which may further inform studies in other organ systems that express this GPCR, such as the lung, testes, and small intestine.
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Affiliation(s)
- Nathan A Zaidman
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Mahendra Damarla
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Josephine Tidmore
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Diane E Capen
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
| | - Oleh M Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Jennifer L Pluznick
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205;
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Hassanzadeh Khayyat N, Kim EY, Dryer SE. TRPC6 inactivation does not protect against diabetic kidney disease in streptozotocin (STZ)-treated Sprague-Dawley rats. FASEB Bioadv 2019; 1:773-782. [PMID: 32123821 PMCID: PMC6996301 DOI: 10.1096/fba.2019-00077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 09/06/2019] [Accepted: 10/30/2019] [Indexed: 01/14/2023] Open
Abstract
Canonical transient receptor potential-6 (TRPC6) channels have been implicated in the progression of several forms of kidney disease (1). While there is strong evidence that glomerular TRPC6 channels are dysregulated in diabetic nephropathy (DN), there is no consensus as to whether deletion or inactivation of TRPC6 is protective in animal models of DN. A previous study in Dahl salt-sensitive rats suggests that TRPC6 knockout has a modest protective effect in streptozotocin (STZ)-induced DN (2). In the present study, we examined whether inactivation of TRPC6 channels by CRISPR/Cas9 editing (Trpc6 del/del rats) affects progression of STZ-induced DN in Sprague-Dawley rats. Wild-type littermates (Trpc6 wt/wt rats) were used as controls. We observed that a single injection of STZ resulted in severe hyperglycemia that was sustained over a 10-week period, accompanied by a marked reduction in circulating C-peptide, dyslipidemia, and failure to gain weight compared to vehicle-treated animals. Those effects were equally severe in Trpc6 wt/wt and Trpc6 del/del rats. STZ treatment resulted in increased urine albumin excretion at 4, 8, and 10 weeks after injection, and this effect was equally severe in Trpc6 wt/wt and Trpc6 del/del rats. TRPC6 inactivation had no effect on blood urea nitrogen (BUN), plasma creatinine concentration, urine nephrin excretion, or kidney weight:body weight ratio measured 10 weeks after STZ injection. STZ treatment evoked modest and equivalent mesangial expansion in Trpc6 wt/wt and Trpc6 del/del rats. In summary, we observed no protective effect of TRPC6 inactivation on STZ-induced DN in rats on the Sprague-Dawley background.
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Affiliation(s)
| | - Eun Young Kim
- Department of Biology and BiochemistryUniversity of HoustonHoustonTXUSA
| | - Stuart E. Dryer
- Department of Biology and BiochemistryUniversity of HoustonHoustonTXUSA
- Department of Biomedical SciencesUniversity of Houston College of MedicineHoustonTXUSA
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Affiliation(s)
| | - Eun Young Kim
- Biology and BiochemistryUniversity of HoustonHoustonTX
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