1
|
Fuchs MAA, Schrankl J, Wagner C, Daniel C, Kurtz A, Broeker KAE. Localization and characterization of proenkephalin-A as a potential biomarker for kidney disease in murine and human kidneys. Biomarkers 2023; 28:76-86. [PMID: 36354355 DOI: 10.1080/1354750x.2022.2146196] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Exact measurement of renal function is essential for the treatment of patients. Elevated serum-creatinine levels, while established, are influenced by other parameters and show a significant time-lag. This drives the search for novel biomarkers of renal function and injury. Beside Lipocalin-2 and kidney-injury-molecule-1 (KIM-1), the endogenous opioid precursor proenkephalin-A (Penk) has recently emerged as a promising marker for renal function. But the cellular origin and regulation of Penk outside the brain has not yet been investigated in depth. MATERIALS AND METHODS This study characterizes the cellular origin of Penk expression with high-resolution in situ hybridization in two models of renal fibrosis in mice and human tissue. RESULTS Interstitial cells are the main expression site for renal Penk. This classifies Penk as biomarker for interstitial damage as opposed to tubular damage markers like Lipocalin-2 and KIM-1. Furthermore, our data indicate that renal Penk expression is not regulated by classical profibrotic pathways. DISCUSSION This study characterizes changing Penk expression in the kidneys. The similarity of Penk expression across species gives rise to further investigations into the function of Penk in healthy and injured kidneys. CONCLUSION Penk is a promising biomarker for interstitial renal damage that warrants further studies to utilize its predictive potential.Clinical significanceKnowledge of real-time renal function is essential for proper treatment of critically ill patients and in early diagnosis of acute kidney injury (AKI). Proenkephalin-A has been measured in a number of patient cohorts as a highly accurate and predictive biomarker of renal damage.The present study identifies Penk as a biomarker for interstitial damage in contrast to the tubular biomarkers such as Lipocalin-2 or KIM-1.Our data show that Penk is regulated independently of classical profibrotic or proinflammatory pathways, indicating it might be more robust against extra-renal influences.Data presented in this study provide fundamental information about cell type-specific localization and regulation of the potential new biomarker Penk across species as foundation for further research.
Collapse
Affiliation(s)
| | - Julia Schrankl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Christoph Daniel
- Department of Nephropathology, Universitätsklinikum Erlangen-Nürnberg, Erlangen, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | | |
Collapse
|
2
|
Broeker KAE, Schrankl J, Fuchs MAA, Kurtz A. Flexible and multifaceted: the plasticity of renin-expressing cells. Pflugers Arch 2022; 474:799-812. [PMID: 35511367 PMCID: PMC9338909 DOI: 10.1007/s00424-022-02694-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 02/04/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 12/14/2022]
Abstract
The protease renin, the key enzyme of the renin–angiotensin–aldosterone system, is mainly produced and secreted by juxtaglomerular cells in the kidney, which are located in the walls of the afferent arterioles at their entrance into the glomeruli. When the body’s demand for renin rises, the renin production capacity of the kidneys commonly increases by induction of renin expression in vascular smooth muscle cells and in extraglomerular mesangial cells. These cells undergo a reversible metaplastic cellular transformation in order to produce renin. Juxtaglomerular cells of the renin lineage have also been described to migrate into the glomerulus and differentiate into podocytes, epithelial cells or mesangial cells to restore damaged cells in states of glomerular disease. More recently, it could be shown that renin cells can also undergo an endocrine and metaplastic switch to erythropoietin-producing cells. This review aims to describe the high degree of plasticity of renin-producing cells of the kidneys and to analyze the underlying mechanisms.
Collapse
Affiliation(s)
- Katharina A E Broeker
- Institute of Physiology, University of Regensburg, Universitätsstraβe 31, D-93053 , Regensburg, Germany.
| | - Julia Schrankl
- Institute of Physiology, University of Regensburg, Universitätsstraβe 31, D-93053 , Regensburg, Germany
| | - Michaela A A Fuchs
- Institute of Physiology, University of Regensburg, Universitätsstraβe 31, D-93053 , Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Universitätsstraβe 31, D-93053 , Regensburg, Germany
| |
Collapse
|
3
|
Fuchs MAA, Schrankl J, Leupold C, Wagner C, Kurtz A, Broeker KAE. Intact prostaglandin signaling through EP2 and EP4 receptors in stromal progenitor cells is required for normal development of the renal cortex in mice. Am J Physiol Renal Physiol 2022; 322:F295-F307. [PMID: 35037469 DOI: 10.1152/ajprenal.00414.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/10/2022] [Indexed: 01/20/2023] Open
Abstract
Cyclooxygenase (Cox) inhibitors are known to have severe side effects during renal development. These consist of reduced renal function, underdeveloped subcapsular glomeruli, interstitial fibrosis, and thinner cortical tissue. Global genetic deletion of Cox-2 mimics the phenotype observed after application of Cox inhibitors. This study aimed to investigate which cell types express Cox-2 and prostaglandin E2 receptors and what functions are mediated through this pathway during renal development. Expression of EP2 and EP4 mRNA was detected by RNAscope mainly in descendants of FoxD1+ stromal progenitors; EP1 and EP3, on the other hand, were expressed in tubules. Cox-2 mRNA was detected in medullary interstitial cells and macula densa cells. Functional investigations were performed with a cell-specific approach to delete Cox-2, EP2, and EP4 in FoxD1+ stromal progenitor cells. Our data show that Cox-2 expression in macula densa cells is sufficient to drive renal development. Deletion of EP2 or EP4 in FoxD1+ cells had no functional effect on renal development. Codeletion of EP2 and EP4 in FoxD1+ stromal cells, however, led to severe glomerular defects and a strong decline of glomerular filtration rate (1.316 ± 69.7 µL/min/100 g body wt in controls vs. 644.1 ± 64.58 µL/min/100 g body wt in FoxD1+/Cre EP2-/- EP4ff mice), similar to global deletion of Cox-2. Furthermore, EP2/EP4-deficient mice showed a significant increase in collagen production with a strong downregulation of renal renin expression. This study shows the distinct localization of EP receptors in mice. Functionally, we could identify EP2 and EP4 receptors in stromal FoxD1+ progenitor cells as essential receptor subtypes for normal renal development.NEW & NOTEWORTHY Cyclooxygenase-2 (Cox-2) produces prostaglandins that are essential for normal renal development. It is unclear in which cells Cox-2 and the receptors for prostaglandin E2 (EP receptors) are expressed during late nephrogenesis. This study identified the expression sites for EP subtypes and Cox-2 in neonatal mouse kidneys. Furthermore, it shows that stromal progenitor cells may require intact prostaglandin E2 signaling through EP2 and EP4 receptors for normal renal development.
Collapse
MESH Headings
- Animals
- Cyclooxygenase 2/genetics
- Cyclooxygenase 2/metabolism
- Forkhead Transcription Factors/genetics
- Forkhead Transcription Factors/metabolism
- Gene Expression Regulation, Developmental
- Kidney Cortex/cytology
- Kidney Cortex/enzymology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Organogenesis
- Prostaglandins/metabolism
- Receptors, Prostaglandin E, EP2 Subtype/genetics
- Receptors, Prostaglandin E, EP2 Subtype/metabolism
- Receptors, Prostaglandin E, EP4 Subtype/genetics
- Receptors, Prostaglandin E, EP4 Subtype/metabolism
- Signal Transduction
- Stem Cells/metabolism
- Stromal Cells/enzymology
- Mice
Collapse
Affiliation(s)
| | - Julia Schrankl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Christina Leupold
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | | |
Collapse
|
4
|
Broeker KAE, Fuchs MAA, Schrankl J, Lehrmann C, Schley G, Todorov VT, Hugo C, Wagner C, Kurtz A. Prolyl-4-hydroxylases 2 and 3 control erythropoietin production in renin-expressing cells of mouse kidneys. J Physiol 2021; 600:671-694. [PMID: 34863041 DOI: 10.1113/jp282615] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 11/29/2021] [Indexed: 12/30/2022] Open
Abstract
Activation of the hypoxia-signalling pathway induced by deletion of the ubiquitin-ligase von Hippel-Lindau protein causes an endocrine shift of renin-producing cells to erythropoietin (EPO)-expressing cells. However, the underlying mechanisms have not yet been investigated. Since oxygen-regulated stability of hypoxia-inducible transcription factors relevant for EPO expression is dependent on the activity of prolyl-4-hydroxylases (PHD) 2 and 3, this study aimed to determine the relevance of different PHD isoforms for the EPO expression in renin-producing cells in vivo. For this purpose, mice with inducible renin cell-specific deletions of different PHD isoforms were analysed. Our study shows that there are two subgroups of renal renin-expressing cells, juxtaglomerular renin+ cells and platelet-derived growth factor receptor-β+ interstitial renin+ cells. These interstitial renin+ cells belong to the cell pool of native EPO-producing cells and are able to express EPO and renin in parallel. In contrast, co-deletion of PHD2 and PHD3, but not PHD2 deletion alone, induces EPO expression in juxtaglomerular and hyperplastic renin+ cells and downregulates renin expression. A strong basal PHD3 expression in juxtaglomerular renin+ cells seems to prevent the hypoxia-inducible transcription factor-2-dependent phenotype shift into EPO cells. In summary, PHDs seem important for the stabilization of the juxtaglomerular renin cell phenotype. Moreover, these findings reveal tubulointerstitial cells as a novel site of renal renin expression and suggest a high endocrine plasticity of these cells. Our data concerning the distinct expression patterns and functions of PHD2 and PHD3 provide new insights into the regulation of renin-producing cells and highlight the need for selective PHD inhibitors. KEY POINTS: Renal renin-expressing cells can be clearly distinguished into two subgroups, the typical juxtaglomerular renin-producing cells and interstitial renin+ cells. Interstitial renin+ cells belong to the cell pool of native erythropoietin (EPO)-producing cells, show a fast EPO response to acute hypoxia-inducible factor-2 (HIF-2) stabilization and are able to express EPO and renin in parallel. Only co-deletion of the prolyl-4-hydroxylases (PHD) 2 and 3, but not PHD2 deletion alone, induces EPO expression in juxtaglomerular renin+ cells. Chronic HIF-2 stabilization in juxtaglomerular renin-expressing cells leads to their phenotypic shift into EPO-producing cells. A strong basal PHD3 expression in juxtaglomerular renin+ cells seems to prevent a HIF-2-dependent phenotype shift into EPO cells suggesting PHD3 fulfils a stabilizer function for the juxtaglomerular renin cell phenotype.
Collapse
Affiliation(s)
| | | | - Julia Schrankl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Claudia Lehrmann
- Institute of Physiology II, University of Regensburg, Regensburg, Germany
| | - Gunnar Schley
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Vladimir T Todorov
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Christian Hugo
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| |
Collapse
|
5
|
Neder TH, Schrankl J, Fuchs MAA, Broeker KAE, Wagner C. Endothelin receptors in renal interstitial cells do not contribute to the development of fibrosis during experimental kidney disease. Pflugers Arch 2021; 473:1667-1683. [PMID: 34355294 PMCID: PMC8433107 DOI: 10.1007/s00424-021-02604-4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/24/2021] [Accepted: 07/01/2021] [Indexed: 11/26/2022]
Abstract
Renal interstitial fibrosis is characterized by the development of myofibroblasts, originating from resident renal and immigrating cells. Myofibroblast formation and extracellular matrix production during kidney damage are triggered by various factors. Among these, endothelins have been discussed as potential modulators of renal fibrosis. Utilizing mouse models of adenine nephropathy (AN) and unilateral ureter occlusion (UUO), this study aimed to investigate the contribution of endothelin signaling in stromal mesenchymal resident renal interstitial cells. We found in controls that adenine feeding and UUO caused marked upregulations of endothelin-1 (ET-1) gene expression in endothelial and in tubular cells and a strong upregulation of ETA-receptor (ETA-R) gene expression in interstitial and mesangial cells, while the gene expression of ETB-receptor (ETB-R) did not change. Conditional deletion of ETA-R and ETB-R gene expression in the FoxD1 stromal cell compartment which includes interstitial cells significantly reduced renal ETA-R gene expression and moderately lowered renal ETB-R gene expression. ET receptor (ET-R) deletion exerted no apparent effects on kidney development nor on kidney function. Adenine feeding and UUO led to similar increases in profibrotic and proinflammatory gene expression in control as well as in ETAflflETBflfl FoxD1Cre+ mice (ET-Ko). In summary, our findings suggest that adenine feeding and UUO activate endothelin signaling in interstitial cells which is due to upregulated ETA-R expression and enhanced renal ET-1 production Our data also suggest that the activation of endothelin signaling in interstitial cells has less impact for the development of experimentally induced fibrosis.
Collapse
Affiliation(s)
- Thomas H Neder
- Institute of Physiology, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany
| | - Julia Schrankl
- Institute of Physiology, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany
| | - Michaela A A Fuchs
- Institute of Physiology, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany
| | - Katharina A E Broeker
- Institute of Physiology, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany.
| |
Collapse
|
6
|
Fuchs MAA, Broeker KAE, Schrankl J, Burzlaff N, Willam C, Wagner C, Kurtz A. Inhibition of transforming growth factor β1 signaling in resident interstitial cells attenuates profibrotic gene expression and preserves erythropoietin production during experimental kidney fibrosis in mice. Kidney Int 2021; 100:122-137. [PMID: 33705825 DOI: 10.1016/j.kint.2021.02.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 02/10/2021] [Accepted: 02/16/2021] [Indexed: 12/13/2022]
Abstract
Kidney fibrosis is characterized by the development of myofibroblasts originating from resident kidney and immigrating cells. Myofibroblast formation and extracellular matrix production during kidney damage are triggered by various cytokines. Among these, transforming growth factor β1 (TGFβ1) is considered a central trigger for kidney fibrosis. We found a highly upregulated expression of TGFβ1 and TGFβ receptor 2 (TGFβ-R2) mRNAs in kidney interstitial cells in experimental fibrosis. Here, we investigated the contribution of TGFβ1 signaling in resident kidney interstitial cells to organ fibrosis using the models of adenine induced nephropathy and unilateral ureteral occlusion in mice. For this purpose TGFβ1 signaling was interrupted by inducible deletion of the TGFβ-R2 gene in interstitial cells expressing the fibroblast marker platelet derived growth factor receptor-β. Expression of profibrotic genes was attenuated up to 50% in kidneys lacking TGFβ-R2 in cells positive for platelet derived growth factor receptor-β. Additionally, deletion of TGFβ-R2 prevented the decline of erythropoietin production in ureter ligated kidneys. Notably, fibrosis associated expression of α-smooth muscle actin as a myofibroblast marker and deposits of extracellular collagens were not altered in mice with targeted deletion of TGFβ-R2. Thus, our findings suggest an enhancing effect of TGFβ1 signaling in resident interstitial cells that contributes to profibrotic gene expression and the downregulation of erythropoietin production, but not to the development of myofibroblasts during kidney fibrosis.
Collapse
Affiliation(s)
| | | | - Julia Schrankl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Nicolai Burzlaff
- Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Carsten Willam
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| |
Collapse
|
7
|
Schrankl J, Fuchs M, Broeker K, Daniel C, Kurtz A, Wagner C. Localization of angiotensin II type 1 receptor gene expression in rodent and human kidneys. Am J Physiol Renal Physiol 2021; 320:F644-F653. [PMID: 33615887 DOI: 10.1152/ajprenal.00550.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The kidneys are an important target for angiotensin II (ANG II). In adult kidneys, the effects of ANG II are mediated mainly by ANG II type 1 (AT1) receptors. AT1 receptor expression has been reported for a variety of different cell types within the kidneys, suggesting a broad spectrum of actions for ANG II. Since there have been heterogeneous results in the literature regarding the intrarenal distribution of AT1 receptors, this study aimed to obtain a comprehensive overview about the localization of AT1 receptor expression in mouse, rat, and human kidneys. Using the cell-specific and high-resolution RNAscope technique, we performed colocalization experiments with various cell markers to specifically discriminate between different segments of the tubular and vascular system. Overall, we found a similar pattern of AT1 mRNA expression in mouse, rat, and human kidneys. AT1 receptors were detected in mesangial cells and renin-producing cells. In addition, AT1 mRNA was found in interstitial cells of the cortex and outer medulla. In rodents, late afferent and early efferent arterioles expressed AT1 receptor mRNA, but larger vessels of the investigated species showed no AT1 expression. Tubular expression of AT1 mRNA was species dependent with a strong expression in proximal tubules of mice, whereas expression was undetectable in human tubular cells. These findings suggest that the (juxta)glomerular area and tubulointerstitium are conserved expression sites for AT1 receptors across species and might present the main target sites for ANG II in adult human and rodent kidneys.NEW & NOTEWORTHY Angiotensin II (ANG II) type 1 (AT1) receptors are essential for mediating the effects of ANG II in the kidneys. This study aimed to obtain a comprehensive overview about the cell-specific localization of AT1 receptor expression in rodent and human kidneys using the novel RNAscope technique. We found that the conserved AT1 receptor mRNA expression sites across species are the (juxta)glomerular areas and tubulointerstitium, which might present main target sites for ANG II in adult human and rodent kidneys.
Collapse
Affiliation(s)
- Julia Schrankl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Michaela Fuchs
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Katharina Broeker
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| |
Collapse
|
8
|
Broeker KA, Fuchs MA, Schrankl J, Kurt B, Nolan KA, Wenger RH, Kramann R, Wagner C, Kurtz A. Different subpopulations of kidney interstitial cells produce erythropoietin and factors supporting tissue oxygenation in response to hypoxia in vivo. Kidney Int 2020; 98:918-931. [DOI: 10.1016/j.kint.2020.04.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 03/30/2020] [Accepted: 04/02/2020] [Indexed: 01/04/2023]
|
9
|
Schrankl J, Neubauer B, Fuchs M, Gerl K, Wagner C, Kurtz A. Apparently normal kidney development in mice with conditional disruption of ANG II-AT 1 receptor genes in FoxD1-positive stroma cell precursors. Am J Physiol Renal Physiol 2019; 316:F1191-F1200. [PMID: 30969804 DOI: 10.1152/ajprenal.00305.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
An intact renin-angiotensin system involving ANG II type 1 (AT1) receptors is crucial for normal kidney development. It is still unclear in which cell types AT1 receptor signaling is required for normal kidney development, maturation, and function. Because all kidney cells deriving from stroma progenitor cells express AT1 receptors and because stromal cells fundamentally influence nephrogenesis and tubular maturation, we investigated the relevance of AT1 receptors in stromal progenitors and their descendants for renal development and function. For this aim, we generated and analyzed mice with conditional deletion of AT1A receptor in the FoxD1 cell lineage in combination with global disruption of the AT1B receptor gene. These FoxD1-AT1ko mice developed normally. Their kidneys showed neither structural nor functional abnormalities compared with wild-type mice, whereas in isolated perfused FoxD1-AT1ko kidneys, the vasoconstrictor and renin inhibitory effects of ANG II were absent. In vivo, however, plasma renin concentration and renal renin expression were normal in FoxD1-AT1ko mice, as were blood pressure and glomerular filtration rate. These findings suggest that a strong reduction of AT1 receptors in renal stromal progenitors and their descendants does not disturb normal kidney development.
Collapse
Affiliation(s)
- Julia Schrankl
- Institute of Physiology, University of Regensburg , Regensburg , Germany
| | - Bjoern Neubauer
- Department of Medicine IV, University Medical Center Freiburg , Freiburg , Germany
| | - Michaela Fuchs
- Institute of Physiology, University of Regensburg , Regensburg , Germany
| | - Katharina Gerl
- Institute of Physiology, University of Regensburg , Regensburg , Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg , Regensburg , Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg , Regensburg , Germany
| |
Collapse
|
10
|
Neubauer B, Schrankl J, Steppan D, Neubauer K, Sequeira-Lopez ML, Pan L, Gomez RA, Coffman TM, Gross KW, Kurtz A, Wagner C. Angiotensin II Short-Loop Feedback: Is There a Role of Ang II for the Regulation of the Renin System In Vivo? Hypertension 2018; 71:1075-1082. [PMID: 29661841 DOI: 10.1161/hypertensionaha.117.10357] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [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: 09/22/2017] [Revised: 10/11/2017] [Accepted: 03/19/2018] [Indexed: 11/16/2022]
Abstract
The activity of the renin-angiotensin-aldosterone system is triggered by the release of the protease renin from the kidneys, which in turn is controlled in the sense of negative feedback loops. It is widely assumed that Ang II (angiotensin II) directly inhibits renin expression and secretion via a short-loop feedback by an effect on renin-producing cells (RPCs) mediated by AT1 (Ang II type 1) receptors. Because the concept of such a direct short-loop negative feedback control, which originates mostly from in vitro experiments, has not yet been systematically proven in vivo, we aimed to test the validity of this concept by studying the regulation of renin synthesis and secretion in mice lacking Ang II-AT1 receptors on RPCs. We found that RPCs of the kidney express Ang II-AT1 receptors. Mice with conditional deletion of Ang II-AT1 receptors in RPCs were normal with regard to the number of renin cells, renal renin mRNA, and plasma renin concentrations. Renin expression and secretion of these mice responded to Ang I (angiotensin I)-converting enzyme inhibition and to Ang II infusion like in wild-type (WT) controls. In summary, we did not obtain evidence that Ang II-AT1 receptors on RPCs are of major relevance for the normal regulation of renin expression and secretion in mice. Therefore, we doubt the existence of a direct negative feedback function of Ang II on RPCs.
Collapse
Affiliation(s)
- Bjoern Neubauer
- From the Institute of Physiology, University of Regensburg, Germany (B.N., J.S., D.S., K.N., A.K., C.W.)
| | - Julia Schrankl
- From the Institute of Physiology, University of Regensburg, Germany (B.N., J.S., D.S., K.N., A.K., C.W.)
| | - Dominik Steppan
- From the Institute of Physiology, University of Regensburg, Germany (B.N., J.S., D.S., K.N., A.K., C.W.)
| | - Katharina Neubauer
- From the Institute of Physiology, University of Regensburg, Germany (B.N., J.S., D.S., K.N., A.K., C.W.).,Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Medical Center-University of Freiburg, Germany (K.N.)
| | - Maria Luisa Sequeira-Lopez
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville (M.L.S.-L., R.A.G.)
| | - Li Pan
- Department of Pathology, Brigham and Women's Hospital, Boston, MA (L.P.)
| | - R Ariel Gomez
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville (M.L.S.-L., R.A.G.)
| | - Thomas M Coffman
- Division of Nephrology, Department of Medicine, Durham Veterans Affairs Medical Centers, Duke University, NC (T.M.C.).,and Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY (K.W.G.)
| | - Kenneth W Gross
- and Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY (K.W.G.)
| | - Armin Kurtz
- From the Institute of Physiology, University of Regensburg, Germany (B.N., J.S., D.S., K.N., A.K., C.W.)
| | - Charlotte Wagner
- From the Institute of Physiology, University of Regensburg, Germany (B.N., J.S., D.S., K.N., A.K., C.W.)
| |
Collapse
|