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Zapf AM, Grimm PR, Al-Qusairi L, Delpire E, Welling PA. Low Salt Delivery Triggers Autocrine Release of Prostaglandin E2 From the Aldosterone-Sensitive Distal Nephron in Familial Hyperkalemic Hypertension Mice. Front Physiol 2022; 12:787323. [PMID: 35069250 PMCID: PMC8770744 DOI: 10.3389/fphys.2021.787323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
Aberrant activation of with-no-lysine kinase (WNK)-STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) kinase signaling in the distal convoluted tubule (DCT) causes unbridled activation of the thiazide-sensitive sodium chloride cotransporter (NCC), leading to familial hyperkalemic hypertension (FHHt) in humans. Studies in FHHt mice engineered to constitutively activate SPAK specifically in the DCT (CA-SPAK mice) revealed maladaptive remodeling of the aldosterone sensitive distal nephron (ASDN), characterized by decrease in the potassium excretory channel, renal outer medullary potassium (ROMK), and epithelial sodium channel (ENaC), that contributes to the hyperkalemia. The mechanisms by which NCC activation in DCT promotes remodeling of connecting tubule (CNT) are unknown, but paracrine communication and reduced salt delivery to the ASDN have been suspected. Here, we explore the involvement of prostaglandin E2 (PGE2). We found that PGE2 and the terminal PGE2 synthase, mPGES1, are increased in kidney cortex of CA-SPAK mice, compared to control or SPAK KO mice. Hydrochlorothiazide (HCTZ) reduced PGE2 to control levels, indicating increased PGE2 synthesis is dependent on increased NCC activity. Immunolocalization studies revealed mPGES1 is selectively increased in the CNT of CA-SPAK mice, implicating low salt-delivery to ASDN as the trigger. Salt titration studies in an in vitro ASDN cell model, mouse CCD cell (mCCD-CL1), confirmed PGE2 synthesis is activated by low salt, and revealed that response is paralleled by induction of mPGES1 gene expression. Finally, inhibition of the PGE2 receptor, EP1, in CA-SPAK mice partially restored potassium homeostasis as it partially rescued ROMK protein abundance, but not ENaC. Together, these data indicate low sodium delivery to the ASDN activates PGE2 synthesis and this inhibits ROMK through autocrine activation of the EP1 receptor. These findings provide new insights into the mechanism by which activation of sodium transport in the DCT causes remodeling of the ASDN.
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Affiliation(s)
- Ava M Zapf
- Molecular Medicine, Graduate Program in Life Sciences, University of Maryland Medical School, Baltimore, MD, United States
| | - Paul R Grimm
- Department of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Lama Al-Qusairi
- Department of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University Medical School, Nashville, TN, United States
| | - Paul A Welling
- Department of Medicine, Johns Hopkins University, Baltimore, MD, United States.,Department of Physiology, Johns Hopkins University, Baltimore, MD, United States
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2
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Wang L, Wu Y, Jia Z, Yu J, Huang S. Roles of EP Receptors in the Regulation of Fluid Balance and Blood Pressure. Front Endocrinol (Lausanne) 2022; 13:875425. [PMID: 35813612 PMCID: PMC9262144 DOI: 10.3389/fendo.2022.875425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/23/2022] [Indexed: 11/23/2022] Open
Abstract
Prostaglandin E2 (PGE2) is an important prostanoid expressing throughout the kidney and cardiovascular system. Despite the diverse effects on fluid metabolism and blood pressure, PGE2 is implicated in sustaining volume and hemodynamics homeostasis. PGE2 works through four distinct E-prostanoid (EP) receptors which are G protein-coupled receptors. To date, pharmacological specific antagonists and agonists of all four subtypes of EP receptors and genetic targeting knockout mice for each subtype have helped in uncoupling the diverse functions of PGE2 and discriminating the respective characteristics of each receptor. In this review, we summarized the functions of individual EP receptor subtypes in the renal and blood vessels and the molecular mechanism of PGE2-induced fluid metabolism and blood pressure homeostasis.
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Affiliation(s)
- Lu Wang
- Jiangsu Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Department of Hematology and Oncology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Yiqian Wu
- Jiangsu Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Jiangsu Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Jing Yu
- Jiangsu Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- *Correspondence: Songming Huang, ; Jing Yu,
| | - Songming Huang
- Jiangsu Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
- *Correspondence: Songming Huang, ; Jing Yu,
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Chen X, Yin J, Xu Y, Qiu Z, Liu J, Chen X. Effect of selective inhibition or activation of PGE2 EP1 receptor on glomerulosclerosis. Mol Med Rep 2020; 22:2887-2895. [PMID: 32700746 PMCID: PMC7453572 DOI: 10.3892/mmr.2020.11353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 06/19/2020] [Indexed: 11/16/2022] Open
Abstract
Prostaglandin E2 (PGE2) is involved in numerous physiological and pathological processes of the kidney via its four receptors. A previous study has suggested that a defect in the PGE2 receptor 1 (EP1) gene markedly suppressed the transforming growth factor-β1 (TGF-β1)-induced mesangial cell (MC) proliferation and extracellular matrix aggregation. Therefore, the present study aimed to adopt a pharmacological method of specifically suppressing or activating the EP1 receptor to further verify and demonstrate these results. The EP1 receptor antagonist SC-19220 and EP1 receptor agonist 17-phenyl-trinor-PGE2 ethyl amide (17-pt-PGE2) were selectively used to treat five-sixths nephrectomy renal fibrosis model mice and TGF-β1-stimulated MCs. An Alpha screen PGE2 assay kit, flow cytometry, western blotting and immunohistochemical techniques were adopted to perform in vivo and in vitro experiments. The present results suggested that compared with the control group, the selective EP1 receptor antagonist SC-19220 improved renal function, markedly reduced the plasma blood urea nitrogen and creatinine levels (P<0.05) and alleviated glomerulosclerosis (P<0.05). By contrast, the EP1 receptor agonist 17-pt-PGE2 aggravated renal dysfunction and glomerulosclerosis (P<0.05). To verify the renal protection mechanisms mediated by suppression of the EP1 receptor, the expression levels of endoplasmic reticulum stress (ERS)-related proteins, including chaperone glucose-regulated protein 78 (GRP78), transient receptor potential channel 1 (TRPC1) and protein kinase R-like endoplasmic reticulum kinase (PERK), were further evaluated histologically. The expression of GRP78, TRPC1 and PERK in the antagonist treatment group were markedly downregulated (P<0.05), whereas those in the agonist treatment group were upregulated (P<0.05). The present in vitro experiments demonstrated that, compared with the control group, the EP1 receptor antagonist suppressed the expression of GRP78, TRPC1 and PERK (P<0.05), reduced the production of PGE2 (P<0.05) and decreased the MC apoptosis rate (P<0.05), thus alleviating TGF-β1-stimulated MC injury. Consequently, consistent with previous results, selectively antagonizing the EP1 receptor improved renal function and mitigated glomerulosclerosis, and its potential mechanism might be associated with the suppression of ERS.
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Affiliation(s)
- Xu Chen
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Jun Yin
- Department of Nephrology, Wuxi No. 2 People's Hospital, Wuxi, Jiangsu 214000, P.R. China
| | - Yuyin Xu
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Zhi Qiu
- Department of Emergency Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Jing Liu
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Xiaolan Chen
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
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Arora M, Choudhary S, Singh PK, Sapra B, Silakari O. Structural investigation on the selective COX-2 inhibitors mediated cardiotoxicity: A review. Life Sci 2020; 251:117631. [PMID: 32251635 DOI: 10.1016/j.lfs.2020.117631] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 03/31/2020] [Indexed: 01/30/2023]
Abstract
Initially, the selective COX-2 inhibitors were developed as safer alternatives to the conventional NSAIDs, but later on, most of them were withdrawn from the market due to the risk of heart attack and stroke. Celecoxib, the first selective COX-2 inhibitor, was approved by the Food and Drug Administration (FDA) in December 1998 and was taken back from the market in 2004. Since then, many coxibs have been discontinued one by one due to adverse cardiovascular events. United States (US), Australian and European authorities related to Therapeutic Goods Administration (TGA) implemented the requirements to carry the "Black box" warning on the labels of COX-2 drugs highlighting the risks of serious cardiovascular events. These facts encouraged the researchers to explore them well and find out the biochemical basis behind the cardiotoxicity. From the last few decades, the molecular mechanisms behind the coxibs have regained the attention, especially the specific structural features of the selective COX-2 inhibitors that are associated with cardiotoxicity. This review discusses the key structural features of the selective COX-2 inhibitors and underlying mechanisms that are responsible for the cardiotoxicity. This report also unfolds different strategies that have been reported in the last 10 years to combat the problem of selective COX-2 inhibitors mediated cardiotoxicity.
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Affiliation(s)
- Mohit Arora
- Molecular Modelling Lab (MML), Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab 147002, India
| | - Shalki Choudhary
- Molecular Modelling Lab (MML), Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab 147002, India
| | - Pankaj Kumar Singh
- Department of Chemistry and Pharmacy, University of Sassari, 07100 Sassari, Italy
| | - Bharti Sapra
- Molecular Modelling Lab (MML), Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab 147002, India
| | - Om Silakari
- Molecular Modelling Lab (MML), Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab 147002, India.
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5
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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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6
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Gonzalez AA, Gallardo M, Cespedes C, Vio CP. Potassium Intake Prevents the Induction of the Renin-Angiotensin System and Increases Medullary ACE2 and COX-2 in the Kidneys of Angiotensin II-Dependent Hypertensive Rats. Front Pharmacol 2019; 10:1212. [PMID: 31680980 PMCID: PMC6804396 DOI: 10.3389/fphar.2019.01212] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 09/20/2019] [Indexed: 01/13/2023] Open
Abstract
In angiotensin II (Ang II)-dependent hypertensive rats there is an increased expression of proximal tubule angiotensinogen (AGT), collecting duct renin and angiotensin converting enzyme (ACE), which contributes to intratubular Ang II formation. Ang II acts on Ang II type 1 receptors promoting sodium retention and vasoconstriction. However concurrently, the ACE2-Ang-(1–7) axis and the expression of kallikrein and medullary prostaglandins counteract the effects of Ang II, promoting natriuresis and vasodilation. Human studies demonstrate that dietary potassium (K+) intake lowers blood pressure. In this report we evaluate the expression of AGT, ACE, medullary prorenin/renin, ACE2, kallikrein and cyclooxygenase-2 (COX-2) in Ang II-infused rats fed with high K+ diet (2%) for 14 days. Dietary K+ enhances diuresis in non-infused and in Ang II-infused rats. The rise in systolic blood pressure in Ang II-infused rats was attenuated by dietary K+. Ang II-infused rats showed increased renal protein levels of AGT, ACE and medullary prorenin and renin. This effect was attenuated in the Ang II + K+ group. Ang II infusion decreased ACE2 compared to the control group; however, K+ diet prevented this effect in the renal medulla. Furthermore, medullary COX-2 was dramatically induced by K+ diet in non-infused and in Ang II infused rats. Dietary K+ greatly increased kallikrein immunostaining in normotensive rats and in Ang II-hypertensive rats. These results indicate that a high K+ diet attenuates Ang II-dependent hypertension by preventing the induction of ACE, AGT and collecting duct renin and by enhancing medullary COX-2 and ACE2 protein expression in the kidney.
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Affiliation(s)
- Alexis A Gonzalez
- Institute of Chemistry, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Matias Gallardo
- Institute of Chemistry, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Carlos Cespedes
- Department of Physiology, Center for Aging and Regeneration CARE UC, Pontificia Universidad Católica de Chile, Santiago, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Carlos P Vio
- Department of Physiology, Center for Aging and Regeneration CARE UC, Pontificia Universidad Católica de Chile, Santiago, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
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7
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Miyoshi M, Sato M, Saito K, Otani L, Shirahige K, Miura F, Ito T, Jia H, Kato H. Maternal Protein Restriction Alters the Renal Ptger1 DNA Methylation State in SHRSP Offspring. Nutrients 2018; 10:nu10101436. [PMID: 30301128 PMCID: PMC6213780 DOI: 10.3390/nu10101436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 09/25/2018] [Accepted: 09/28/2018] [Indexed: 11/18/2022] Open
Abstract
We previously reported that maternal protein restriction (LP) during pregnancy increases salt sensitivity in offspring using the Stroke-Prone Spontaneously Hypertensive Rat (SHRSP). In the present study, we focus on DNA methylation profiles of prostaglandin E receptor 1 gene (ptger1), which is known to be associated with hypertension. We evaluated the ptger1 DNA methylation status via bisulfite sequencing, and analyzed the expression of ptger1-related genes. The results of these analyses showed that, compared to controls, the LP-S offspring exhibited both marked ptger1 hypermethylation, and significantly increased ptger1 expression. Moreover, they also exhibited significantly decreased expression of the downstream gene epithelial Na+ channel alpha (enacα). Interestingly, LP offspring that were provided with a standard water drinking supply (W) also exhibited increased ptger1 methylation and expression. Together, these results suggest that maternal protein restriction during pregnancy modulates the renal ptger1 DNA methylation state in SHRSP offspring, and thereby likely mediates ptger1 and enacα gene expression to induce salt sensitivity.
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Affiliation(s)
- Moe Miyoshi
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 1138657, Japan.
| | - Masayuki Sato
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 1138657, Japan.
| | - Kenji Saito
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 1138657, Japan.
| | - Lila Otani
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 1138657, Japan.
| | - Katsuhiko Shirahige
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 1130032, Japan.
| | - Fumihito Miura
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan.
| | - Takashi Ito
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan.
| | - Huijuan Jia
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 1138657, Japan.
| | - Hisanori Kato
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 1138657, Japan.
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Masuda T, Watanabe Y, Fukuda K, Watanabe M, Onishi A, Ohara K, Imai T, Koepsell H, Muto S, Vallon V, Nagata D. Unmasking a sustained negative effect of SGLT2 inhibition on body fluid volume in the rat. Am J Physiol Renal Physiol 2018; 315:F653-F664. [PMID: 29790389 PMCID: PMC6734084 DOI: 10.1152/ajprenal.00143.2018] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/08/2018] [Accepted: 05/16/2018] [Indexed: 12/25/2022] Open
Abstract
The chronic intrinsic diuretic and natriuretic tone of sodium-glucose cotransporter 2 (SGLT2) inhibitors is incompletely understood because their effect on body fluid volume (BFV) has not been fully evaluated and because they often increase food and fluid intake at the same time. Here we first compared the effect of the SGLT2 inhibitor ipragliflozin (Ipra, 0.01% in diet for 8 wk) and vehicle (Veh) in Spontaneously Diabetic Torii rat, a nonobese type 2 diabetic model, and nondiabetic Sprague-Dawley rats. In nondiabetic rats, Ipra increased urinary excretion of Na+ (UNaV) and fluid (UV) associated with increased food and fluid intake. Diabetes increased these four parameters, but Ipra had no further effect, probably because of its antihyperglycemic effect, such that glucosuria and, as a consequence, food and fluid intake were unchanged. Fluid balance and BFV, determined by bioimpedance spectroscopy, were similar among the four groups. To study the impact of food and fluid intake, nondiabetic rats were treated for 7 days with Veh, Ipra, or Ipra+pair feeding+pair drinking (Pair-Ipra). Pair-Ipra maintained a small increase in UV and UNaV versus Veh despite similar food and fluid intake. Pair-Ipra induced a negative fluid balance and decreased BFV, whereas Ipra or Veh had no significant effect compared with basal values. In conclusion, SGLT2 inhibition induces a sustained diuretic and natriuretic tone. Homeostatic mechanisms are activated to stabilize BFV, including compensatory increases in fluid and food intake.
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Affiliation(s)
- Takahiro Masuda
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Yuko Watanabe
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Keiko Fukuda
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Minami Watanabe
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Akira Onishi
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Ken Ohara
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Toshimi Imai
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Hermann Koepsell
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg , Würzburg , Germany
| | - Shigeaki Muto
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Volker Vallon
- Division of Nephrology and Hypertension, Departments of Medicine and Pharmacology, University of California San Diego and VA San Diego Healthcare System, San Diego, CA
| | - Daisuke Nagata
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
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Prostaglandin E 2 Induces Prorenin-Dependent Activation of (Pro)renin Receptor and Upregulation of Cyclooxygenase-2 in Collecting Duct Cells. Am J Med Sci 2017; 354:310-318. [PMID: 28918839 DOI: 10.1016/j.amjms.2017.05.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/26/2017] [Accepted: 05/28/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Prostaglandin E2 (PGE2) regulates renin expression in renal juxtaglomerular cells. PGE2 acts through E-prostanoid (EP) receptors in the renal collecting duct (CD) to regulate sodium and water balance. CD cells express EP1 and EP4, which are linked to protein kinase C (PKC) and PKA downstream pathways, respectively. Previous studies showed that the presence of renin in the CD, and that of PKC and PKA pathways, activate its expression. The (pro)renin receptor (PRR) is also expressed in CD cells, and its activation enhances cyclooxygenase-2 (COX-2) through extracellular signal-regulated kinase (ERK). We hypothesized that PGE2 stimulates prorenin and renin synthesis leading to subsequent activation of PRR and upregulation of COX-2. METHODS We used a mouse M-1 CD cell line that expresses EP1, EP3 and EP4 but not EP2. RESULTS PGE2 (10-6M) treatment increased prorenin and renin protein levels at 4 and 8 hours. No differences were found at 12-hour after PGE2 treatment. Phospho-ERK was significantly augmented after 12 hours. COX-2 expression was decreased after 4 hours of PGE2 treatment, but increased after 12 hours. Interestingly, the full-length form of the PRR was upregulated only at 12 hours. PGE2-mediated phospho-ERK and COX-2 upregulation was suppressed by PRR silencing. CONCLUSIONS Our results suggest that PGE2 induces biphasic regulation of COX-2 through renin-dependent PRR activation via EP1 and EP4 receptors. PRR-mediated increases in COX-2 expression may enhance PGE2 synthesis in CD cells serving as a buffer mechanism in conditions of activated renin-angiotensin system.
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10
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Quadri SS, Culver SA, Li C, Siragy HM. Interaction of the renin angiotensin and cox systems in the kidney. Front Biosci (Schol Ed) 2016; 8:215-26. [PMID: 27100703 DOI: 10.2741/s459] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cyclooxygenase-2 (COX-2) plays an important role in mediating actions of the renin-angiotensin system (RAS). This review sheds light on the recent developments regarding the complex interactions between components of RAS and COX-2; and their implications on renal function and disease. COX-2 is believed to counter regulate the effects of RAS activation and therefore counter balance the vasoconstriction effect of Ang II. In kidney, under normal conditions, these systems are essential for maintaining a balance between vasodilation and vasoconstriction. However, recent studies suggested a pivotal role for this interplay in pathology. COX-2 increases the renin release and Ang II formation leading to increase in blood pressure. COX-2 is also associated with diabetic nephropathy, where its upregulation in the kidney contributes to glomerular injury and albuminuria. Selective inhibition of COX-2 retards the progression of renal injury. COX-2 also mediates the pathologic effects of the (Pro)renin receptor (PRR) in the kidney. In summary, this review discusses the interaction between the RAS and COX-2 in health and disease.
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Affiliation(s)
- Syed S Quadri
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, VA
| | - Silas A Culver
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, VA
| | - Caixia Li
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, VA
| | - Helmy M Siragy
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, VA,
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Abstract
PURPOSE OF REVIEW Renal collecting ducts maintain NaCl homeostasis by fine-tuning urinary excretion to balance dietary salt intake. This review focuses on recent studies on transcellular Cl secretion by collecting ducts, its regulation and its role in cyst growth in autosomal dominant polycystic kidney disease (ADPKD). RECENT FINDINGS Lumens of nonperfused rat medullary collecting ducts collapse in control media but expand with fluid following treatment with cAMP, demonstrating the capacity for both salt absorption and secretion. Recently, inhibition of apical epithelial Na channels (ENaC) unmasked Cl secretion in perfused mouse cortical collecting ducts (CCDs), involving Cl uptake by basolateral NKCC1 and efflux through apical Cl channels. AVP, the key hormone for osmoregulation, promotes cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl secretion. In addition, prostaglandin E2 stimulates Cl secretion through both CFTR and Ca-activated Cl channels. SUMMARY Renal Cl secretion has been commonly overlooked because of the overwhelming capacity for the nephron to reabsorb NaCl from the glomerular filtrate. In ADPKD, Cl secretion plays a central role in the accumulation of cyst fluid and the remarkable size of the cystic kidneys. Investigation of renal Cl secretion may provide a better understanding of NaCl homeostasis and identify new approaches to reduce cyst growth in PKD.
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12
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Role of the prostaglandin E2/E-prostanoid 2 receptor signalling pathway in TGFβ-induced mice mesangial cell damage. Biosci Rep 2014; 34:e00159. [PMID: 25327961 PMCID: PMC4266927 DOI: 10.1042/bsr20140130] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The prostaglandin E2 receptor, EP2 (E-prostanoid 2), plays an important role in mice glomerular MCs (mesangial cells) damage induced by TGFβ1 (transforming growth factor-β1); however, the molecular mechanisms for this remain unknown. The present study examined the role of the EP2 signalling pathway in TGFβ1-induced MCs proliferation, ECM (extracellular matrix) accumulation and expression of PGES (prostaglandin E2 synthase). We generated primary mice MCs. Results showed MCs proliferation promoted by TGFβ1 were increased; however, the production of cAMP and PGE2 (prostaglandin E2) was decreased. EP2 deficiency in these MCs augmented FN (fibronectin), Col I (collagen type I), COX2 (cyclooxygenase-2), mPGES-1 (membrane-associated prostaglandin E1), CTGF (connective tissue growth factor) and CyclinD1 expression stimulated by TGFβ1. Silencing of EP2 also strengthened TGFβ1-induced p38MAPK (mitogen-activated protein kinase), ERK1/2 (extracellular-signal-regulated kinase 1/2) and CREB1 (cAMP responsive element-binding protein 1) phosphorylation. In contrast, Adenovirus-mediated EP2 overexpression reversed the effects of EP2-siRNA (small interfering RNA). Collectively, the investigation indicates that EP2 may block p38MAPK, ERK1/2 and CREB1 phosphorylation via activation of cAMP production and stimulation of PGE2 through EP2 receptors which prevent TGFβ1-induced MCs damage. Our findings also suggest that pharmacological targeting of EP2 receptors may provide new inroads to antagonize the damage induced by TGFβ1.
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Chen X, Jiang D, Wang J, Chen X, Xu X, Xi P, Fan Y, Zhang X, Guan Y. Prostaglandin E2 EP1 receptor enhances TGF-β1-induced mesangial cell injury. Int J Mol Med 2014; 35:285-93. [PMID: 25352206 DOI: 10.3892/ijmm.2014.1979] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 10/15/2014] [Indexed: 11/05/2022] Open
Abstract
Increasing evidence indicates that transforming growth factor-β1 (TGF-β1) is a pivotal mediator in the pathogenesis of renal fibrosis. Mesangial cells (MCs) are important for glomerular function under both physiological and pathological conditions. Studies have found that the expression level of prostaglandin E2 (PGE2) in MCs increases under high glucose conditions, that PGE2 affects the proliferation and hypertrophy of MCs mainly through the EP1 pathway, and that the proliferation of MCs and the accumulation of extracellular matrix are the main events leading to glomerular fibrosis. In this study, we investigated the effects and mechanisms of action of the EP1 receptor, which is induced by transforming growth factor (TGF)-β1, on the proliferation of mouse MCs, the accumulation of extracellular matrix and the expression of PGE2 synthase. Primary mouse glomerular MCs were isolated from EP1 receptor-deficient mice (EP1-/- mice, in which the EP1 receptor was knocked down) and wild-type (WT) mice (WT MCs). In our preliminary experiments, we found that cell proliferation, as well as the mRNA and protein expression of cyclin D1, proliferating cell nuclear antigen (PCNA), fibronectin (FN), collagen I (ColI), membrane-associated PGE2 synthase-1 (mPGES-1) and cyclooxygenase-2 (COX-2) in the WT MCs were significantly increased following treatment with 10 ng/ml TGF-β1 for 24 h. Compared with the WT MCs, following the knockdown of the EP1 gene, the TGF-β1-induced MC injury was markedly suppressed. The aforementioned changes were notably enhanced following treatment with the EP1 agonist, 17-phenyl trinor PGE2 ethyl amide. Additionally, TGF-β1 induced extracellular signal-regulated kinase (ERK) phosphorylation. We found that the TGF-β1-induced ERK phosphorylation was alleviated by EP1 knockdown and promoted by EP1 expression. These results suggest that the EP1 receptor plays a role in the proliferation of mouse MCs, in the accumulation of extracellular matrix and in the expression of mPGES-1 induced by TGF-β1. Its mechanisms of action are possibly related to the reinforcement of ERK phosphorylation.
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Affiliation(s)
- Xu Chen
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Daishan Jiang
- Department of Emergency Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Jing Wang
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Xiaolan Chen
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Xiaolin Xu
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Peipei Xi
- Department of Emergency Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Yaping Fan
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Xiaoyan Zhang
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
| | - Youfei Guan
- Department of Nephrology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, P.R. China
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Abstract
In the mammalian kidney, prostaglandins (PGs) are important mediators of physiologic processes, including modulation of vascular tone and salt and water. PGs arise from enzymatic metabolism of free arachidonic acid (AA), which is cleaved from membrane phospholipids by phospholipase A2 activity. The cyclooxygenase (COX) enzyme system is a major pathway for metabolism of AA in the kidney. COX are the enzymes responsible for the initial conversion of AA to PGG2 and subsequently to PGH2, which serves as the precursor for subsequent metabolism by PG and thromboxane synthases. In addition to high levels of expression of the "constitutive" rate-limiting enzyme responsible for prostanoid production, COX-1, the "inducible" isoform of cyclooxygenase, COX-2, is also constitutively expressed in the kidney and is highly regulated in response to alterations in intravascular volume. PGs and thromboxane A2 exert their biological functions predominantly through activation of specific 7-transmembrane G-protein-coupled receptors. COX metabolites have been shown to exert important physiologic functions in maintenance of renal blood flow, mediation of renin release and regulation of sodium excretion. In addition to physiologic regulation of prostanoid production in the kidney, increases in prostanoid production are also seen in a variety of inflammatory renal injuries, and COX metabolites may serve as mediators of inflammatory injury in renal disease.
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Affiliation(s)
- Raymond C Harris
- George M. O'Brien Kidney and Urologic Diseases Center and Division of Nephrology, Vanderbilt University School of Medicine and Nashville Veterans Affairs Hospital, Nashville, Tennessee, USA.
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Curiel RV, Katz JD. Mitigating the Cardiovascular and Renal Effects of NSAIDs: Table 1. PAIN MEDICINE 2013; 14 Suppl 1:S23-8. [DOI: 10.1111/pme.12275] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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West CA, Shaw S, Sasser JM, Fekete A, Alexander T, Cunningham MW, Masilamani SME, Baylis C. Chronic vasodilation increases renal medullary PDE5A and α-ENaC through independent renin-angiotensin-aldosterone system pathways. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1133-40. [PMID: 24068049 PMCID: PMC3841800 DOI: 10.1152/ajpregu.00003.2013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 09/19/2013] [Indexed: 02/05/2023]
Abstract
We have previously observed that many of the renal and hemodynamic adaptations seen in normal pregnancy can be induced in virgin female rats by chronic systemic vasodilation. Fourteen-day vasodilation with sodium nitrite or nifedipine (NIF) produced plasma volume expansion (PVE), hemodilution, and increased renal medullary phosphodiesterase 5A (PDE5A) protein. The present study examined the role of the renin-angiotensin-aldosterone system (RAAS) in this mechanism. Virgin females were treated for 14 days with NIF (10 mg·kg(-1)·day(-1) via diet), NIF with spironolactone [SPR; mineralocorticoid receptor (MR) blocker, 200-300 mg·kg(-1)·day(-1) via diet], NIF with losartan [LOS; angiotensin type 1 (AT1) receptor blocker, 20 mg·kg(-1)·day(-1) via diet], enalapril (ENAL; angiotensin-converting enzyme inhibitor, 62.5 mg/l via water), or vehicle (CON). Mean arterial pressure (MAP) was reduced 7.4 ± 0.5% with NIF, 6.33 ± 0.5% with NIF + SPR, 13.3 ± 0.9% with NIF + LOS, and 12.0 ± 0.4% with ENAL vs. baseline MAP. Compared with CON (3.6 ± 0.3%), plasma volume factored for body weight was increased by NIF (5.2 ± 0.4%) treatment but not by NIF + SPR (4.3 ± 0.3%), NIF + LOS (3.6 ± 0.1%), or ENAL (4.0 ± 0.3%). NIF increased PDE5A protein abundance in the renal inner medulla, and SPR did not prevent this increase (188 ± 16 and 204 ± 22% of CON, respectively). NIF increased the α-subunit of the epithelial sodium channel (α-ENaC) protein in renal outer (365 ± 44%) and inner (526 ± 83%) medulla, and SPR prevented these changes. There was no change in either PDE5A or α-ENaC abundance vs. CON in rats treated with NIF + LOS or ENAL. These data indicate that the PVE and renal medullary adaptations in response to chronic vasodilation result from RAAS signaling, with increases in PDE5A mediated through AT1 receptor and α-ENaC through the MR.
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Affiliation(s)
- Crystal A West
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
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Zhang Y, Li L, Kohan DE, Ecelbarger CM, Kishore BK. Attenuation of lithium-induced natriuresis and kaliuresis in P2Y₂ receptor knockout mice. Am J Physiol Renal Physiol 2013; 305:F407-16. [PMID: 23739592 DOI: 10.1152/ajprenal.00464.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Whole body knockout (KO) of the P2Y₂ receptor (P2Y₂R) results in enhanced vasopressin V2 receptor activity and increased renal Na⁺ conservation. We hypothesized that P2Y₂R KO mice would be less sensitive to lithium-induced natriuresis and kaliuresis due to attenuated downregulation of one or more of the major renal Na⁺ or K⁺ transporter/channel proteins. KO and wild-type (WT) mice were fed a control or lithium-added diet (40 mmol/kg food) for 14 days. Lithium-induced natriuresis and kaliuresis were significantly (~25%) attenuated in KO mice. The subunits of the epithelial Na⁺ channel (ENaC) were variably affected by lithium and genotype, but, overall, medullary levels were decreased substantially by lithium (15-60%) in both genotypes. In contrast, cortical, β-, and γ-ENaC were increased by lithium (~50%), but only in WT mice. Moreover, an assessment of ENaC activity by benzamil sensitivity suggested that lithium increased ENaC activity in WT mice but in not KO mice. In contrast, medullary levels of Na⁺-K⁺-2Cl⁻ cotransporter 2 and cortical levels of the renal outer medullary K⁺ channel were not downregulated by lithium and were significantly (15-76%) higher in KO mice under both dietary conditions. In addition, under control conditions, tissue osmolality of the inner medulla as well as furosemide sensitivity were significantly higher in KO mice versus WT mice. Therefore, we suggest that increased expression of these proteins, particularly in the control state, reduces Na⁺ delivery to the distal nephron and provides a buffer to attenuate collecting duct-mediated natriuresis and kaliuresis. Additional studies are warranted to explore the potential therapeutic benefits of purinergic antagonism.
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Affiliation(s)
- Yue Zhang
- Nephrology Research, Department of Veterans Administration Salt Lake City Health Care System, Salt Lake City, UT 84148, USA
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Identification of prostaglandin receptors in human ureters. BMC Urol 2012; 12:35. [PMID: 23227994 PMCID: PMC3576244 DOI: 10.1186/1471-2490-12-35] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/07/2012] [Indexed: 01/02/2023] Open
Abstract
Background Prostaglandins play an important role in ureteral obstruction, but the detailed expression profiles of the prostaglandin receptors (PTGER1, PTGER2, PTGER3, PTGER4, PTGFR) remain unknown in the different parts of the human ureter. Methods The expression pattern of PTGER1, PTGER2, PTGER3, PTGER4 and PTGFR was determined in human distal, mid and proximal ureter and renal pelvis samples using immunohistochemistry (protein levels) and quantitative real-time PCR (mRNA). Results PTGER1 was highly expressed in most samples irrespective of the ureteral localization; however, urothelial cells had higher levels of PTGER1 than smooth muscle cells. PTGFR was also moderately to strongly expressed in urothelial and smooth muscle cells. In comparison, PTGER2-4 expression was mostly unexpressed or weakly expressed in urothelial and smooth cells in all regions. Conclusions Our data indicate high levels of PTGER1 in ureters.
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Abstract
Prostanoids are prominent, yet complex, components in the maintenance of body water homeostasis. Recent functional and molecular studies have revealed that the local lipid mediator PGE2 is involved both in water excretion and absorption. The biologic actions of PGE2 are exerted through four different G-protein-coupled receptors; designated EP1-4, which couple to separate intracellular signaling pathways. Here, we discuss new developments in our understanding of the actions of PGE2 that have been uncovered utilizing receptor specific agonists and antagonists, EP receptor and PG synthase knockout mice, polyuric animal models, and the new understanding of the molecular regulation of collecting duct water permeability. The role of PGE2 in urinary concentration comprises a variety of mechanisms, which are not fully understood and likely depend on which receptor is activated under a particular physiologic condition. EP3 and microsomal PG synthase type 1 play a role in decreasing collecting duct water permeability and increasing water excretion, whereas EP2 and EP4 can bypass vasopressin signaling and increase water reabsorption through two different intracellular signaling pathways. PGE2 has an intricate role in urinary concentration, and we now suggest how targeting specific prostanoid receptor signaling pathways could be exploited for the treatment of disorders in water balance.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Vio CP, Quiroz-Munoz M, Cuevas CA, Cespedes C, Ferreri NR. Prostaglandin E2 EP3 receptor regulates cyclooxygenase-2 expression in the kidney. Am J Physiol Renal Physiol 2012; 303:F449-57. [PMID: 22622465 DOI: 10.1152/ajprenal.00634.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Cyclooxygenase-2 (COX-2) is constitutively expressed and highly regulated in the thick ascending limb (TAL). As COX-2 inhibitors (Coxibs) increase COX-2 expression, we tested the hypothesis that a negative feedback mechanism involving PGE(2) EP3 receptors regulates COX-2 expression in the TAL. Sprague-Dawley rats were treated with a Coxib [celecoxib (20 mg·kg(-1)·day(-1)) or rofecoxib (10 mg·kg(-1)·day(-1))], with or without sulprostone (20 μg·kg(-1)·day(-1)). Sulprostone was given using two protocols, namely, previous to Coxib treatment (prevention effect; Sulp7-Coxib5 group) and 5 days after initiation of Coxib treatment (regression effect; Coxib10-Sulp5 group). Immunohistochemical and morphometric analysis revealed that the stained area for COX-2-positive TAL cells (μm(2)/field) increased in Coxib-treated rats (Sham: 412 ± 56.3, Coxib: 794 ± 153.3). The Coxib effect was inhibited when sulprostone was used in either the prevention (285 ± 56.9) or regression (345 ± 51.1) protocols. Western blot analysis revealed a 2.1 ± 0.3-fold increase in COX-2 protein expression in the Coxib-treated group, an effect abolished by sulprostone using either the prevention (1.2 ± 0.3-fold) or regression (0.6 ± 0.4-fold vs. control, P < 0.05) protocols. Similarly, the 6.4 ± 0.6-fold increase in COX-2 mRNA abundance induced by Coxibs (P < 0.05) was inhibited by sulprostone; prevention: 0.9 ± 0.3-fold (P < 0.05) and regression: 0.6 ± 0.1 (P < 0.05). Administration of a selective EP3 receptor antagonist, L-798106, also increased the area for COX-2-stained cells, COX-2 mRNA accumulation, and protein expression in the TAL. Collectively, the data suggest that COX-2 levels are regulated by a novel negative feedback loop mediated by PGE(2) acting on its EP3 receptor in the TAL.
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Affiliation(s)
- Carlos P Vio
- Dept. of Physiology, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Alameda 340, Santiago, Chile.
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The complex interplay between cyclooxygenase-2 and angiotensin II in regulating kidney function. Curr Opin Nephrol Hypertens 2012; 21:7-14. [PMID: 22080858 DOI: 10.1097/mnh.0b013e32834d9d75] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE OF REVIEW Cyclooxygenase-2 (COX-2) plays a critical role in modulating deleterious actions of angiotensin II (Ang II) where there is an inappropriate activation of the renin-angiotensin system (RAS). This review discusses the recent developments regarding the complex interactions by which COX-2 modulates the impact of an activated RAS on kidney function and blood pressure. RECENT FINDINGS Normal rats with increased COX-2 activity but with different intrarenal Ang II activity because of sodium restriction or chronic treatment with angiotensin-converting enzyme (ACE) inhibitors showed similar renal hemodynamic responses to COX-2-selective inhibition (nimesulide) indicating independence from the intrarenal Ang II activity. COX-2-dependent maintenance of medullary blood flow was consistent and not dependent on dietary salt or ACE inhibition. In contrast, COX-2 influences on sodium excretion were contingent on the prevailing RAS activity. In chronic hypertensive models, COX-2 inhibition elicited similar reductions in kidney function, but COX-2 metabolites contribute to rather than ameliorate the hypertension. SUMMARY The maintenance of renal hemodynamics reflects direct and opposing effects of Ang II and COX-2 metabolites. The antagonism in water and electrolyte reabsorption is dependent on the prevailing intrarenal Ang II activity. The recent functional experiments demonstrate a beneficial modulation of Ang II by COX-2 except in the presence of inflammation promoted by hypertension, hyperglycemia, and oxidative stress.
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Nasrallah R, Paris G, Hébert RL. Hypertonicity increases sodium transporters in cortical collecting duct cells independently of PGE2. Biochem Biophys Res Commun 2012; 418:372-7. [PMID: 22266310 DOI: 10.1016/j.bbrc.2012.01.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 01/06/2012] [Indexed: 12/21/2022]
Abstract
Cyclooxygenase-2 (COX-2) expression is increased by hypertonicity. Therefore we hypothesized that hypertonicity increased PGE(2) can modulate the sodium transporters (Na(+)/K(+)-ATPase: NKA, epithelial sodium channel: ENaC, and sodium hydrogen exchanger: NHE) in M1 cortical collecting duct (CCD) cells. We demonstrated by immunoblotting a 2-fold increase in NKA expression and activity following hypertonic treatment. α-ENaC was also increased, however sgk1, an ENaC activator, decreased in response to hypertonicity. Other CCD sodium transporters (β-ENaC, NHE) were unchanged. Hypertonicity also increased PGE(2) but EP(4) receptor mRNA was unaltered. PGE(2) increased intracellular Na(+) and cAMP production in M1 cells, but PGE(2)-stimulated cAMP response was attenuated by hypertonicity. Overall, PGE(2) had no effect on sodium transporter levels. Since neither COX inhibition nor EP(4) siRNA altered the induction of NKA, we propose that sodium transporter regulation by hypertonicity is independent of PGE(2). Altogether, these data indicate that despite a concomitant increase in PGE(2) production and sodium transporter expression in hypertonicity, both pathways are acting independently of each other.
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Affiliation(s)
- Rania Nasrallah
- Department of Cellular and Molecular Medicine, Kidney Research Centre, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5
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Woodward DF, Jones RL, Narumiya S. International Union of Basic and Clinical Pharmacology. LXXXIII: classification of prostanoid receptors, updating 15 years of progress. Pharmacol Rev 2011; 63:471-538. [PMID: 21752876 DOI: 10.1124/pr.110.003517] [Citation(s) in RCA: 321] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
It is now more than 15 years since the molecular structures of the major prostanoid receptors were elucidated. Since then, substantial progress has been achieved with respect to distribution and function, signal transduction mechanisms, and the design of agonists and antagonists (http://www.iuphar-db.org/DATABASE/FamilyIntroductionForward?familyId=58). This review systematically details these advances. More recent developments in prostanoid receptor research are included. The DP(2) receptor, also termed CRTH2, has little structural resemblance to DP(1) and other receptors described in the original prostanoid receptor classification. DP(2) receptors are more closely related to chemoattractant receptors. Prostanoid receptors have also been found to heterodimerize with other prostanoid receptor subtypes and nonprostanoids. This may extend signal transduction pathways and create new ligand recognition sites: prostacyclin/thromboxane A(2) heterodimeric receptors for 8-epi-prostaglandin E(2), wild-type/alternative (alt4) heterodimers for the prostaglandin FP receptor for bimatoprost and the prostamides. It is anticipated that the 15 years of research progress described herein will lead to novel therapeutic entities.
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Affiliation(s)
- D F Woodward
- Dept. of Biological Sciences RD3-2B, Allergan, Inc., 2525 Dupont Dr., Irvine, CA 92612, USA.
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