1
|
Zheng K, Layton AT. Predicting sex differences in the effects of diuretics in renal epithelial transport during angiotensin II-induced hypertension. Am J Physiol Renal Physiol 2024; 326:F737-F750. [PMID: 38482554 DOI: 10.1152/ajprenal.00398.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 04/26/2024] Open
Abstract
Chronic angiotensin II (ANG II) infusion is an experimental model that induces hypertension in rodents. The natriuresis, diuresis, and blood pressure responses differ between males and females. This is perhaps not unexpected, given the rodent kidney, which plays a key role in blood pressure regulation, exhibits marked sex differences. Under normotensive conditions, compared with males, the female rat nephron exhibits lower Na+/H+ exchanger 3 (NHE3) activity along the proximal tubule but higher Na+ transporter activities along the distal segments. ANG II infusion-induced hypertension induces a pressure natriuretic response that reduces NHE3 activity and shifts Na+ transport capacity downstream. The goals of this study were to apply a computational model of epithelial transport along a rat nephron 1) to understand how a 14-day ANG II infusion impacts segmental electrolyte transport in male and female rat nephrons and 2) to identify and explain any sex differences in the effects of loop diuretics, thiazide diuretics, and K+-sparing diuretics. Model simulations suggest that the NHE3 downregulation in the proximal tubule is a major contributor to natriuresis and diuresis in hypertension, with the effects stronger in males. All three diuretics are predicted to induce stronger natriuretic and diuretic effects under hypertension compared with normotension, with relative increases in sodium excretion higher in hypertensive females than in males. The stronger natriuretic responses can be explained by the downstream shift of Na+ transport load in hypertension and by the larger distal transport load in females, both of which limit the ability of the distal segments to further elevate their Na+ transport.NEW & NOTEWORTHY Sex differences in the prevalence of hypertension are found in human and animal models. The kidney, which regulates blood pressure, exhibits sex differences in morphology, hemodynamics, and membrane transporter distributions. This computational modeling study provides insights into how the sexually dimorphic responses to a 14-day angiotensin II infusion differentially impact segmental electrolyte transport in rats. Simulations of diuretic administration explain how the natriuretic and diuretic effects differ between normotension and hypertension and between the sexes.
Collapse
Affiliation(s)
- Kaixin Zheng
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Anita T Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
- Department of Biology, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
| |
Collapse
|
2
|
McDonough AA, Harris AN, Xiong LI, Layton AT. Sex differences in renal transporters: assessment and functional consequences. Nat Rev Nephrol 2024; 20:21-36. [PMID: 37684523 PMCID: PMC11090267 DOI: 10.1038/s41581-023-00757-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2023] [Indexed: 09/10/2023]
Abstract
Mammalian kidneys are specialized to maintain fluid and electrolyte homeostasis. The epithelial transport processes along the renal tubule that match output to input have long been the subject of experimental and theoretical study. However, emerging data have identified a new dimension of investigation: sex. Like most tissues, the structure and function of the kidney is regulated by sex hormones and chromosomes. Available data demonstrate sex differences in the abundance of kidney solute and electrolyte transporters, establishing that renal tubular organization and operation are distinctly different in females and males. Newer studies have provided insights into the physiological consequences of these sex differences. Computational simulations predict that sex differences in transporter abundance are likely driven to optimize reproduction, enabling adaptive responses to the nutritional requirements of serial pregnancies and lactation - normal life-cycle changes that challenge the ability of renal transporters to maintain fluid and electrolyte homeostasis. Later in life, females may also undergo menopause, which is associated with changes in disease risk. Although numerous knowledge gaps remain, ongoing studies will provide further insights into the sex-specific mechanisms of sodium, potassium, acid-base and volume physiology throughout the life cycle, which may lead to therapeutic opportunities.
Collapse
Affiliation(s)
- Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
| | - Autumn N Harris
- Department of Small Animal Clinical Sciences, University of Florida, College of Veterinary Medicine, Gainesville, FL, USA
| | - Lingyun Ivy Xiong
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA
| | - Anita T Layton
- Departments of Applied Mathematics and Biology, University of Waterloo, Waterloo, Ontario, Canada
- Cheriton School of Computer Science, University of Waterloo, Waterloo, Ontario, Canada
- School of Pharmacy, University of Waterloo, Waterloo, Ontario, Canada
| |
Collapse
|
3
|
Duan XP, Xiao Y, Su XT, Zheng JY, Gurley S, Emathinger J, Yang CL, McCormick J, Ellison DH, Lin DH, Wang WH. Role of Angiotensin II Type 1a Receptor (AT1aR) of Renal Tubules in Regulating Inwardly Rectifying Potassium Channels 4.2 (Kir4.2), Kir4.1, and Epithelial Na + Channel (ENaC). Hypertension 2024; 81:126-137. [PMID: 37909221 PMCID: PMC10842168 DOI: 10.1161/hypertensionaha.123.21389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/12/2023] [Indexed: 11/02/2023]
Abstract
BACKGROUND Kir4.2 and Kir4.1 play a role in regulating membrane transport in the proximal tubule (PT) and in the distal-convoluted-tubule (DCT), respectively. METHODS We generated kidney-tubule-specific-AT1aR-knockout (Ks-AT1aR-KO) mice to examine whether renal AT1aR regulates Kir4.2 and Kir4.1. RESULTS Ks-AT1aR-KO mice had a lower systolic blood pressure than Agtr1aflox/flox (control) mice. Ks-AT1aR-KO mice had a lower expression of NHE3 (Na+/H+-exchanger 3) and Kir4.2, a major Kir-channel in PT, than Agtr1aflox/flox mice. Whole-cell recording also demonstrated that the membrane potential in PT of Ks-AT1aR-KO mice was lesser negative than Agtr1aflox/flox mice. The expression of Kir4.1 and Kir5.1, Kir4.1/Kir5.1-mediated K+ currents of DCT and DCT membrane potential in Ks-AT1aR-KO mice, were similar to Agtr1aflox/flox mice. However, angiotensin II perfusion for 7 days hyperpolarized the membrane potential in PT and DCT of the control mice but not in Ks-AT1aR-KO mice, while angiotensin II perfusion did not change the expression of Kir4.1, Kir4.2, and Kir5.1. Deletion of AT1aR did not significantly affect the expression of αENaC (epithelial Na+ channel) and βENaC but increased cleaved γENaC expression. Patch-clamp experiments demonstrated that deletion of AT1aR increased amiloride-sensitive Na+-currents in the cortical-collecting duct but not in late-DCT. However, tertiapin-Q sensitive renal outer medullary potassium channel currents were similar in both genotypes. CONCLUSIONS AT1aR determines the baseline membrane potential of PT by controlling Kir4.2 expression/activity but AT1aR is not required for determining the baseline membrane potential of the DCT and Kir4.1/Kir5.1 activity/expression. However, AT1aR is required for angiotensin II-induced hyperpolarization of basolateral membrane of PT and DCT. Deletion of AT1aR had no effect on baseline renal outer medullary potassium channel activity but increased ENaC activity in the CCD.
Collapse
Affiliation(s)
- Xin-Peng Duan
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Yu Xiao
- Department of Physiology, Qiqihar Medical College, Heilongjiang, China
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Xiao-Tong Su
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Jun-Ya Zheng
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Susan Gurley
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | | | - Chao-Ling Yang
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - James McCormick
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - David H. Ellison
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, NY
| |
Collapse
|
4
|
Edwards A, Ralph DL, Mercado A, McDonough AA. Angiotensin II hypertension along the female rat tubule: predicted impact on coupled transport of Na + and K . Am J Physiol Renal Physiol 2023; 325:F733-F749. [PMID: 37823196 PMCID: PMC10878725 DOI: 10.1152/ajprenal.00232.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/13/2023] Open
Abstract
Chronic infusion of subpressor level of angiotensin II (ANG II) increases the abundance of Na+ transporters along the distal nephron, balanced by suppression of Na+ transporters along the proximal tubule and medullary thick ascending limb (defined as "proximal nephron"), which impacts K+ handling along the entire renal tubule. The objective of this study was to quantitatively assess the impact of chronic ANG II on the renal handling of Na+ and K+ in female rats, using a computational model of the female rat renal tubule. Our results indicate that the downregulation of proximal nephron Na+ reabsorption (TNa), which occurs in response to ANG II-triggered hypertension, involves changes in both transporter abundance and trafficking. Our model suggests that substantial (∼30%) downregulation of active NHE3 in proximal tubule (PT) microvilli is needed to reestablish the Na+ balance at 2 wk of ANG II infusion. The 35% decrease in SGLT2, a known NHE3 regulator, may contribute to this downregulation. Both depression of proximal nephron TNa and stimulation of distal ENaC raise urinary K+ excretion in ANG II-treated females, while K+ loss is slightly mitigated by cortical NKCC2 and NCC upregulation. Our model predicts that K+ excretion may be more significantly limited during ANG II infusion by ROMK inhibition in the distal nephron and/or KCC3 upregulation in the PT, which remain open questions for experimental validation. In summary, our analysis indicates that ANG II hypertension triggers a series of events from distal TNa stimulation followed by compensatory reduction in proximal nephron TNa and accompanying adjustments to limit excessive K+ secretion.NEW & NOTEWORTHY We used a computational model of the renal tubule to assess the impact of 2-wk angiotensin II (ANG II) infusion on the handling of Na+ and K+ in female rats. ANG II strongly stimulates distal Na+ reabsorption and K+ secretion. Simulations indicate that substantial downregulation of proximal tubule NHE3 is needed to reestablish Na+ balance at 2 wk. Proximal adaptations challenge K+ homeostasis, and regulation of distal NCC and specific K+ channels likely limit urinary K+ losses.
Collapse
Affiliation(s)
- Aurélie Edwards
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California, United States
| | - Adriana Mercado
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California, United States
| |
Collapse
|
5
|
McDonough AA, Layton AT. Sex differences in renal electrolyte transport. Curr Opin Nephrol Hypertens 2023; 32:467-475. [PMID: 37382185 PMCID: PMC10526720 DOI: 10.1097/mnh.0000000000000909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
PURPOSE OF REVIEW Women experience unique life events, for example, pregnancy and lactation, that challenge renal regulation of electrolyte homeostasis. Recent analyses of nephron organization in female vs. male rodent kidneys, revealed distinct sexual dimorphisms in electrolyte transporter expression, abundance, and activity. This review aims to provide an overview of electrolyte transporters' organization and operation in female compared with the commonly studied male kidney, and the (patho)physiologic consequences of the differences. RECENT FINDINGS When electrolyte transporters are assessed in kidney protein homogenates from both sexes, relative transporter abundance ratios in females/males are less than one along proximal tubule and greater than one post macula densa, which is indicative of a 'downstream shift' in fractional reabsorption of electrolytes in females. This arrangement improves the excretion of a sodium load, challenges potassium homeostasis, and is consistent with the lower blood pressure and greater pressure natriuresis observed in premenopausal women. SUMMARY We summarize recently reported new knowledge about sex differences in renal transporters: abundance and expression along nephron, implications for regulation by Na + , K + and angiotensin II, and mathematical models of female nephron function.
Collapse
Affiliation(s)
- Alicia A. McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, CA
| | - Anita T. Layton
- Departments of Applied Mathematics and Biology, University of Waterloo, Waterloo, Ontario, Canada; Cheriton School of Computer Science, University of Waterloo, Waterloo, Ontario, Canada; School of Pharmacy, University of Waterloo, Waterloo, Ontario, Canada
| |
Collapse
|
6
|
Palmer LG. Directing two-way traffic in the kidney: A tale of two ions. J Gen Physiol 2022; 154:213433. [PMID: 36048011 PMCID: PMC9437110 DOI: 10.1085/jgp.202213179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The kidneys regulate levels of Na+ and K+ in the body by varying urinary excretion of the electrolytes. Since transport of each of the two ions can affect the other, controlling both at the same time is a complex task. The kidneys meet this challenge in two ways. Some tubular segments change the coupling between Na+ and K+ transport. In addition, transport of Na+ can shift between segments where it is coupled to K+ reabsorption and segments where it is coupled to K+ secretion. This permits the kidney to maintain electrolyte balance with large variations in dietary intake.
Collapse
Affiliation(s)
- Lawrence G. Palmer
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, NY,Correspondence to Lawrence G. Palmer:
| |
Collapse
|
7
|
Majid DSA, Castillo A. Angiotensin II-induced natriuresis is attenuated in knockout mice lacking the receptors for tumor necrosis factor-α. Physiol Rep 2021; 9:e14942. [PMID: 34337896 PMCID: PMC8326895 DOI: 10.14814/phy2.14942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 11/25/2022] Open
Abstract
Intravenous infusion of relatively higher doses of angiotensin II (AngII) elicits natriuresis as opposed to its usual anti-natruretic response. As AngII can induce tumor necrosis factor-α (TNFα) production which elicits natriuresis via its action on TNFα receptor type 1 (TNFR1), we hypothesize that the concomitant release of TNFα contributes to the natriuretic response to AngII. Responses to AngII infusion (1 ng min-1 g-1 for 75 min, iv) were evaluated in anesthetized knockout (KO) mice lacking TNFR1 (n = 6) and TNFR2 (TNFα receptor type 2; n = 6) and compared these responses with those in wild type (WT; n = 6) mice. Arterial pressure (AP) was recorded from a cannula placed in the carotid artery. Renal blood flow (RBF) and glomerular filtration rate (GFR) were measured by PAH and inulin clearances, respectively. Urine was collected from a catheter placed in the bladder. AngII caused similar increases (p < 0.05 vs basal values) in AP (WT, 37 ± 5%; TNFR1KO, 35 ± 4%; TNFR2KO, 30 ± 4%) and decreases (p < 0.05) in RBF (WT, -39 ± 5%; TNFR1KO, -28 ± 6%; TNFR2KO, -31 ± 4%) without significant changes in GFR (WT, -17 ± 7%; TNFR1KO, -18 ± 7%; TNFR2KO, -12 ± 7%). However, despite similar changes in AP and renal hemodynamics, AngII induced increases (p < 0.05) in urinary sodium excretion in WT (3916 ± 942%) were less in the KO strains, more or less in TNFR1KO (473 ± 170%) than in TNFR2KO (1176 ± 168%). These data indicate that TNF-α receptors, particularly TNFR1 are involved in the natriuretic response that occur during acute infusion of AngII and thus, plays a protective role in preventing excessive salt retention at clinical conditions associated with elevated AngII level.
Collapse
Affiliation(s)
- Dewan S. A. Majid
- Department of PhysiologyTulane Hypertension & Renal Center of ExcellenceTulane University Health Sciences CenterNew OrleansLAUSA
| | - Alexander Castillo
- Department of PhysiologyTulane Hypertension & Renal Center of ExcellenceTulane University Health Sciences CenterNew OrleansLAUSA
| |
Collapse
|
8
|
Wang F, Chen Y, Zou CJ, Luo R, Yang T. Mutagenesis of the Cleavage Site of Pro Renin Receptor Abrogates Angiotensin II-Induced Hypertension in Mice. Hypertension 2021; 78:115-127. [PMID: 34024121 PMCID: PMC9212214 DOI: 10.1161/hypertensionaha.121.16770] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Fei Wang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| | - Yanting Chen
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| | - Chang-jiang Zou
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| | - Renfei Luo
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| | - Tianxin Yang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| |
Collapse
|
9
|
New Insights into the Critical Importance of Intratubular Na +/H + Exchanger 3 and Its Potential Therapeutic Implications in Hypertension. Curr Hypertens Rep 2021; 23:34. [PMID: 34110521 DOI: 10.1007/s11906-021-01152-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2021] [Indexed: 01/08/2023]
Abstract
PURPOSE OF REVIEW The sodium (Na+) and hydrogen (H+) exchanger 3 (NHE3), known as solute carrier family 9 member 3 (SLC9A3), mediates active transcellular Na+ and bicarbonate reabsorption in the small intestine of the gut and proximal tubules of the kidney. The purpose of this article is to review and discuss recent findings on the critical roles of intestinal and proximal tubule NHE3 in maintaining basal blood pressure (BP) homeostasis and their potential therapeutic implications in the development of angiotensin II (Ang II)-dependent hypertension. RECENT FINDINGS Recently, our and other laboratories have generated or used novel genetically modified mouse models with whole-body, kidney-specific, or proximal tubule-specific deletion of NHE3 to determine the critical roles and underlying mechanisms of NHE3 in maintaining basal BP homeostasis and the development of Ang II-induced hypertension at the whole-body, kidney, or proximal tubule levels. The new findings demonstrate that NHE3 contributes to about 10 to 15 mmHg to basal blood pressure levels, and that deletion of NHE3 at the whole-kidney or proximal tubule level, or pharmacological inhibition of NHE3 at the kidney level with an orally absorbable NHE3 inhibitor AVE-0657, attenuates ~ 50% of Ang II-induced hypertension in mice. The results support the proof-of-concept hypothesis that NHE3 plays critical roles in physiologically maintaining normal BP and in the development of Ang II-dependent hypertension. Our results also strongly suggest that NHE3 in the proximal tubules of the kidney may be therapeutically targeted to treat poorly controlled hypertension in humans.
Collapse
|
10
|
Sparks MA, Dilmen E, Ralph DL, Rianto F, Hoang TA, Hollis A, Diaz EJ, Adhikari R, Chew G, Petretto EG, Gurley SB, McDonough AA, Coffman TM. Vascular control of kidney epithelial transporters. Am J Physiol Renal Physiol 2021; 320:F1080-F1092. [PMID: 33969697 PMCID: PMC8285646 DOI: 10.1152/ajprenal.00084.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/23/2021] [Accepted: 05/05/2021] [Indexed: 01/03/2023] Open
Abstract
A major pathway in hypertension pathogenesis involves direct activation of ANG II type 1 (AT1) receptors in the kidney, stimulating Na+ reabsorption. AT1 receptors in tubular epithelia control expression and stimulation of Na+ transporters and channels. Recently, we found reduced blood pressure and enhanced natriuresis in mice with cell-specific deletion of AT1 receptors in smooth muscle (SMKO mice). Although impaired vasoconstriction and preserved renal blood flow might contribute to exaggerated urinary Na+ excretion in SMKO mice, we considered whether alterations in Na+ transporter expression might also play a role; therefore, we carried out proteomic analysis of key Na+ transporters and associated proteins. Here, we show that levels of Na+-K+-2Cl- cotransporter isoform 2 (NKCC2) and Na+/H+ exchanger isoform 3 (NHE3) are reduced at baseline in SMKO mice, accompanied by attenuated natriuretic and diuretic responses to furosemide. During ANG II hypertension, we found widespread remodeling of transporter expression in wild-type mice with significant increases in the levels of total NaCl cotransporter, phosphorylated NaCl cotransporter (Ser71), and phosphorylated NKCC2, along with the cleaved, activated forms of the α- and γ-epithelial Na+ channel. However, the increases in α- and γ-epithelial Na+ channel with ANG II were substantially attenuated in SMKO mice. This was accompanied by a reduced natriuretic response to amiloride. Thus, enhanced urinary Na+ excretion observed after cell-specific deletion of AT1 receptors from smooth muscle cells is associated with altered Na+ transporter abundance across epithelia in multiple nephron segments. These findings suggest a system of vascular-epithelial in the kidney, modulating the expression of Na+ transporters and contributing to the regulation of pressure natriuresis.NEW & NOTEWORTHY The use of drugs to block the renin-angiotensin system to reduce blood pressure is common. However, the precise mechanism for how these medications control blood pressure is incompletely understood. Here, we show that mice lacking angiotensin receptors specifically in smooth muscle cells lead to alternation in tubular transporter amount and function. Thus, demonstrating the importance of vascular-tubular cross talk in the control of blood pressure.
Collapse
Affiliation(s)
- Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
- Renal Section, Durham Veterans Affairs Health Care System, Durham, North Carolina
| | - Emre Dilmen
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Fitra Rianto
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Thien A Hoang
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Alison Hollis
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Edward J Diaz
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Rishav Adhikari
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Gabriel Chew
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
| | - Enrico G Petretto
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
| | - Susan B Gurley
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Thomas M Coffman
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
- Renal Section, Durham Veterans Affairs Health Care System, Durham, North Carolina
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
| |
Collapse
|
11
|
Nelson JW, McDonough AA, Xiang Z, Ralph DL, Robertson JA, Giani JF, Bernstein KE, Gurley SB. Local and downstream actions of proximal tubule angiotensin II signaling on Na + transporters in the mouse nephron. Am J Physiol Renal Physiol 2021; 321:F69-F81. [PMID: 34056928 DOI: 10.1152/ajprenal.00014.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The renal nephron consists of a series of distinct cell types that function in concert to maintain fluid and electrolyte balance and blood pressure. The renin-angiotensin system (RAS) is central to Na+ and volume balance. We aimed to determine how loss of angiotensin II signaling in the proximal tubule (PT), which reabsorbs the bulk of filtered Na+ and volume, impacts solute transport throughout the nephron. We hypothesized that PT renin-angiotensin system disruption would not only depress PT Na+ transporters but also impact downstream Na+ transporters. Using a mouse model in which the angiotensin type 1a receptor (AT1aR) is deleted specifically within the PT (AT1aR PTKO), we profiled the abundance of Na+ transporters, channels, and claudins along the nephron. Absence of PT AT1aR signaling was associated with lower abundance of PT transporters (Na+/H+ exchanger isoform 3, electrogenic Na+-bicarbonate cotransporter 1, and claudin 2) as well as lower abundance of downstream transporters (total and phosphorylated Na+-K+-2Cl- cotransporter, medullary Na+-K+-ATPase, phosphorylated NaCl cotransporter, and claudin 7) versus controls. However, transport activities of Na+-K+-2Cl- cotransporter and NaCl cotransporter (assessed with diuretics) were similar between groups in order to maintain electrolyte balance. Together, these results demonstrate the primary impact of angiotensin II regulation on Na+ reabsorption in the PT at baseline and the associated influence on downstream Na+ transporters, highlighting the ability of the nephron to integrate Na+ transport along the nephron to maintain homeostasis.NEW & NOTEWORTHY Our study defines a novel role for proximal tubule angiotensin receptors in regulating the abundance of Na+ transporters throughout the nephron, thereby contributing to the integrated control of fluid balance in vivo.
Collapse
Affiliation(s)
- Jonathan W Nelson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Zhidan Xiang
- Wake Forest University, Winston-Salem, North Carolina
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Joshua A Robertson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jorge F Giani
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Kenneth E Bernstein
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Susan B Gurley
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| |
Collapse
|
12
|
Angiotensin II up-regulates sodium-glucose co-transporter 2 expression and SGLT2 inhibitor attenuates Ang II-induced hypertensive renal injury in mice. Clin Sci (Lond) 2021; 135:943-961. [PMID: 33822013 DOI: 10.1042/cs20210094] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/01/2021] [Accepted: 04/06/2021] [Indexed: 02/07/2023]
Abstract
Clinical trials indicate that sodium/glucose co-transporter 2 (SGLT2) inhibitors (SGLT2i) improve kidney function, yet, the molecular regulation of SGLT2 expression is incompletely understood. Here, we investigated the role of the intrarenal renin-angiotensin system (RAS) on SGLT2 expression. In adult non-diabetic participants in the Nephrotic Syndrome Study Network (NEPTUNE, n=163), multivariable linear regression analysis showed SGLT2 mRNA was significantly associated with angiotensinogen (AGT), renin, and angiotensin-converting enzyme (ACE) mRNA levels (P<0.001). In vitro, angiotensin II (Ang II) dose-dependently stimulated SGLT2 expression in HK-2, human immortalized renal proximal tubular cells (RPTCs); losartan and antioxidants inhibited it. Sglt2 expression was increased in transgenic (Tg) mice specifically overexpressing Agt in their RPTCs, as well as in WT mice with a single subcutaneous injection of Ang II (1.44 mg/kg). Moreover, Ang II (1000 ng/kg/min) infusion via osmotic mini-pump in WT mice for 4 weeks increased systolic blood pressure (SBP), glomerulosclerosis, tubulointerstitial fibrosis, and albuminuria; canaglifozin (Cana, 15 mg/kg/day) reversed these changes, with the exception of SBP. Fractional glucose excretion (FeGlu) was higher in Ang II+Cana than WT+Cana, whereas Sglt2 expression was similar. Our data demonstrate a link between intrarenal RAS and SGLT2 expression and that SGLT2i ameliorates Ang II-induced renal injury independent of SBP.
Collapse
|
13
|
Lins BB, Casare FAM, Fontenele FF, Gonçalves GL, Oliveira-Souza M. Long-Term Angiotensin II Infusion Induces Oxidative and Endoplasmic Reticulum Stress and Modulates Na + Transporters Through the Nephron. Front Physiol 2021; 12:642752. [PMID: 33868007 PMCID: PMC8046928 DOI: 10.3389/fphys.2021.642752] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/05/2021] [Indexed: 01/10/2023] Open
Abstract
High plasma angiotensin II (Ang II) levels are related to many diseases, including hypertension, and chronic kidney diseases (CKDs). Here, we investigated the relationship among prolonged Ang II infusion/AT1 receptor (AT1R) activation, oxidative stress, and endoplasmic reticulum (ER) stress in kidney tissue. In addition, we explored the chronic effects of Ang II on tubular Na+ transport mechanisms. Male Wistar rats were subjected to sham surgery as a control or prolonged Ang II treatment (200 ng⋅kg–1⋅min–1, 42 days) with or without losartan (10 mg⋅kg–1⋅day–1) for 14 days. Ang II/AT1R induced hypertension with a systolic blood pressure of 173.0 ± 20 mmHg (mmHg, n = 9) compared with 108.0 ± 7 mmHg (mmHg, n = 7) in sham animals. Under these conditions, gene and protein expression levels were evaluated. Prolonged Ang II administration/AT1R activation induced oxidative stress and ER stress with increased Nox2, Nox4, Cyba and Ncf1 mRNA expression, phosphorylated PERK and eIF2α protein expression as well as Atf4 mRNA expression. Ang II/AT1R also raised Il1b, Nfkb1 and Acta2 mRNA expression, suggesting proinflammatory, and profibrotic effects. Regarding Na+ tubular handling, Ang II/AT1R enhanced cortical non-phosphorylated and phospho/S552/NHE3, NHE1, ENaC β, NKCC2, and NCC protein expression. Our results also highlight the therapeutic potential of losartan, which goes beyond the antihypertensive effect, playing an important role in kidney tissue. This treatment reduced oxidative stress and ER stress signals and recovered relevant parameters of the maintenance of renal function, preventing the progression of Ang II-induced CKD.
Collapse
Affiliation(s)
- Bruna Bezerra Lins
- Laboratory of Renal Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Fernando Augusto Malavazzi Casare
- Laboratory of Renal Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Flávia Ferreira Fontenele
- Laboratory of Renal Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Guilherme Lopes Gonçalves
- Laboratory of Renal Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Maria Oliveira-Souza
- Laboratory of Renal Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| |
Collapse
|
14
|
Simões e Silva AC, Lanza K, Palmeira VA, Costa LB, Flynn JT. 2020 update on the renin-angiotensin-aldosterone system in pediatric kidney disease and its interactions with coronavirus. Pediatr Nephrol 2021; 36:1407-1426. [PMID: 32995920 PMCID: PMC7524035 DOI: 10.1007/s00467-020-04759-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/12/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
Abstract
The last decade was crucial for our understanding of the renin-angiotensin-aldosterone system (RAAS) as a two-axis, counter-regulatory system, divided into the classical axis, formed by angiotensin-converting enzyme (ACE), angiotensin II (Ang II), and the angiotensin type 1 receptor (AT1R), and the alternative axis comprising angiotensin-converting enzyme 2 (ACE2), angiotensin-(1-7) (Ang-(1-7)), and the Mas receptor. Breakthrough discoveries also took place, with other RAAS endopeptides being described, including alamandine and angiotensin A. In this review, we characterize the two RAAS axes and the role of their components in pediatric kidney diseases, including childhood hypertension (HTN), pediatric glomerular diseases, congenital abnormalities of the kidney and urinary tract (CAKUT), and chronic kidney disease (CKD). We also present recent findings on potential interactions between the novel coronavirus, SARS-CoV-2, and components of the RAAS, as well as potential implications of coronavirus disease 2019 (COVID-19) for pediatric kidney diseases.
Collapse
Affiliation(s)
- Ana Cristina Simões e Silva
- grid.8430.f0000 0001 2181 4888Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Avenida Alfredo Balena, 190, 2nd floor, Room # 281, Belo Horizonte, MG 30130-100 Brazil ,grid.8430.f0000 0001 2181 4888Pediatric Nephrology Unit, Department of Pediatrics, Faculty of Medicine, UFMG, Belo Horizonte, Brazil
| | - Katharina Lanza
- grid.8430.f0000 0001 2181 4888Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Avenida Alfredo Balena, 190, 2nd floor, Room # 281, Belo Horizonte, MG 30130-100 Brazil
| | - Vitória Andrade Palmeira
- grid.8430.f0000 0001 2181 4888Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Avenida Alfredo Balena, 190, 2nd floor, Room # 281, Belo Horizonte, MG 30130-100 Brazil
| | - Larissa Braga Costa
- grid.8430.f0000 0001 2181 4888Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Avenida Alfredo Balena, 190, 2nd floor, Room # 281, Belo Horizonte, MG 30130-100 Brazil
| | - Joseph T. Flynn
- grid.34477.330000000122986657Pediatric Nephrology, Seattle Children’s Hospital, University of Washington School of Medicine, Seattle, WA 98105 USA
| |
Collapse
|
15
|
High blood pressure induced by vitamin D deficiency is associated with renal overexpression and hyperphosphorylation of Na+-K+-2Cl- cotransporter type 2. J Hypertens 2020; 39:880-891. [PMID: 33337598 DOI: 10.1097/hjh.0000000000002745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Clinical and epidemiological studies have suggested a correlation between vitamin D deficiency (VDD) and high blood pressure (BP). This study aimed to test the hypothesis that high BP induced by VDD is associated with altered expression and covalent modification of apical sodium transporters along the nephron. The contributions of the intrarenal renin-angiotensin system (RAS) and oxidative stress were also investigated. METHODS Male Wistar rats were fed a vitamin D-free (n = 26) or standard diet (n = 25) for 30 days. BP was recorded using noninvasive and invasive procedures. The expression levels of total and phosphorylated apical sodium transporters in rat renal cortex and medulla were evaluated by immunoblotting. Intrarenal RAS components were assessed by immunoblotting and ELISA. Renal oxidative stress was analyzed by measuring the concentrations of thiobarbituric acid reactive substances and reduced glutathione. RESULTS Higher BP levels in VDD rats than controls were accompanied by overexpression and hyperphosphorylation of renal cortical and medullary Na+-K+-2Cl- cotransporter type 2, enhanced levels of phosphorylated Na+/H+ exchanger type 3, and reduced expression levels of total and phosphorylated Na+/Cl- cotransporter. Changes in intrarenal RAS induced by VDD vs. controls included the marked elevation of medullary renin expression, higher expression of cortical angiotensinogen, higher urinary angiotensinogen excretion, and higher cortical and medullary angiotensin II content. VDD rats displayed higher thiobarbituric acid reactive substances/glutathione ratios in the renal cortex and medulla than controls. CONCLUSION These results suggest that the molecular mechanisms underlying the effects of VDD on BP may include the upregulation of Na+-K+-2Cl- cotransporter type 2 and activation of intrarenal RAS and oxidative stress.
Collapse
|
16
|
Hering L, Rahman M, Hoch H, Markó L, Yang G, Reil A, Yakoub M, Gupta V, Potthoff SA, Vonend O, Ralph DL, Gurley SB, McDonough AA, Rump LC, Stegbauer J. α2A-Adrenoceptors Modulate Renal Sympathetic Neurotransmission and Protect against Hypertensive Kidney Disease. J Am Soc Nephrol 2020; 31:783-798. [PMID: 32086277 DOI: 10.1681/asn.2019060599] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Increased nerve activity causes hypertension and kidney disease. Recent studies suggest that renal denervation reduces BP in patients with hypertension. Renal NE release is regulated by prejunctional α2A-adrenoceptors on sympathetic nerves, and α2A-adrenoceptors act as autoreceptors by binding endogenous NE to inhibit its own release. However, the role of α2A-adrenoceptors in the pathogenesis of hypertensive kidney disease is unknown. METHODS We investigated effects of α2A-adrenoceptor-regulated renal NE release on the development of angiotensin II-dependent hypertension and kidney disease. In uninephrectomized wild-type and α2A-adrenoceptor-knockout mice, we induced hypertensive kidney disease by infusing AngII for 28 days. RESULTS Urinary NE excretion and BP did not differ between normotensive α2A-adrenoceptor-knockout mice and wild-type mice at baseline. However, NE excretion increased during AngII treatment, with the knockout mice displaying NE levels that were significantly higher than those of wild-type mice. Accordingly, the α2A-adrenoceptor-knockout mice exhibited a systolic BP increase, which was about 40 mm Hg higher than that found in wild-type mice, and more extensive kidney damage. In isolated kidneys, AngII-enhanced renal nerve stimulation induced NE release and pressor responses to a greater extent in kidneys from α2A-adrenoceptor-knockout mice. Activation of specific sodium transporters accompanied the exaggerated hypertensive BP response in α2A-adrenoceptor-deficient kidneys. These effects depend on renal nerves, as demonstrated by reduced severity of AngII-mediated hypertension and improved kidney function observed in α2A-adrenoceptor-knockout mice after renal denervation. CONCLUSIONS Our findings reveal a protective role of prejunctional inhibitory α2A-adrenoceptors in pathophysiologic conditions with an activated renin-angiotensin system, such as hypertensive kidney disease, and support the concept of sympatholytic therapy as a treatment.
Collapse
Affiliation(s)
- Lydia Hering
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Masudur Rahman
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Henning Hoch
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Lajos Markó
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbruck Center for Molecular Medicine, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,Charité Medical Faculty Berlin, Berlin, Germany
| | - Guang Yang
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,The Shenzhen Key Laboratory of Health Sciences and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
| | - Annika Reil
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Mina Yakoub
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Vikram Gupta
- Department of Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Sebastian A Potthoff
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Oliver Vonend
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Nierenzentrum, DKD Helios Medical Center, Wiesbaden, Germany
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Susan B Gurley
- Division of Nephrology and Hypertension, School of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Lars C Rump
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Johannes Stegbauer
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany;
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Edwards A, McDonough AA. Impact of angiotensin II-mediated stimulation of sodium transporters in the nephron assessed by computational modeling. Am J Physiol Renal Physiol 2019; 317:F1656-F1668. [PMID: 31657247 DOI: 10.1152/ajprenal.00335.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Angiotensin II (ANG II) raises blood pressure partly by stimulating tubular Na+ reabsorption. The effects of ANG II on tubular Na+ transporters (i.e., channels, pumps, cotransporters, and exchangers) vary between short-term and long-term exposure. To better understand the physiological impact, we used a computational model of transport along the rat nephron to predict the effects of short- and long-term ANG II-induced transporter activation on Na+ and K+ reabsorption/secretion, and to compare measured and calculated excretion rates. Three days of ANG II infusion at 200 ng·kg-1·min-1 is nonpressor, yet stimulates transporter accumulation. The increase in abundance of Na+/H+ exchanger 3 (NHE3) or activated Na+-K+-2Cl- cotransporter-2 (NKCC2-P) predicted significant reductions in urinary Na+ excretion, yet there was no observed change in urine Na+. The lack of antinatriuresis, despite Na+ transporter accumulation, was supported by Li+ and creatinine clearance measurements, leading to the conclusion that 3-day nonpressor ANG II increases transporter abundance without proportional activation. Fourteen days of ANG II infusion at 400 ng·kg-1·min-1 raises blood pressure and increases Na+ transporter abundance along the distal nephron; proximal tubule and medullary loop transporters are decreased and urine Na+ and volume output are increased, evidence for pressure natriuresis. Simulations indicate that decreases in NHE3 and NKCC2-P contribute significantly to reducing Na+ reabsorption along the nephron and to pressure natriuresis. Our results also suggest that differential regulation of medullary (decrease) and cortical (increase) NKCC2-P is important to preserve K+ while minimizing Na+ retention during ANG II infusion. Lastly, our model indicates that accumulation of active Na+-Cl- cotransporter counteracts epithelial Na+ channel-induced urinary K+ loss.
Collapse
Affiliation(s)
- Aurélie Edwards
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of University of Southern California, Los Angeles, California
| |
Collapse
|
19
|
Li XC, Zhu D, Chen X, Zheng X, Zhao C, Zhang J, Soleimani M, Rubera I, Tauc M, Zhou X, Zhuo JL. Proximal Tubule-Specific Deletion of the NHE3 (Na +/H + Exchanger 3) in the Kidney Attenuates Ang II (Angiotensin II)-Induced Hypertension in Mice. Hypertension 2019; 74:526-535. [PMID: 31352824 DOI: 10.1161/hypertensionaha.119.13094] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The present study directly tested the hypothesis that the NHE3 (Na+/H+ exchanger 3) in the proximal tubules of the kidney is required for the development of Ang II (angiotensin II)-induced hypertension using PT-Nhe3-/- (proximal tubule-specific NHE3 knockout) mice. Specifically, PT-Nhe3-/- mice were generated using the SGLT2-Cre/Nhe3loxlox approach, whereas Ang II-induced hypertension was studied in 12 groups (n=5-12 per group) of adult male and female wild-type (WT) and PT-Nhe3-/- mice. Under basal conditions, systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure were significantly lower in male and female PT-Nhe3-/- than WT mice (P<0.01). A high pressor, 1.5 mg/kg per day, intraperitoneal or a slow pressor dose of Ang II, 0.5 mg/kg per day, intraperitoneal for 2 weeks significantly increased systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure in male and female WT mice (P<0.01), but the hypertensive response to Ang II was markedly attenuated in male and female PT-Nhe3-/- mice (P<0.01). Ang II impaired the pressure-natriuresis response in WT mice, whereas proximal tubule-specific deletion of NHE3 improved the pressure-natriuresis response in Ang II-infused PT-Nhe3-/- mice (P<0.01). AT1 receptor blocker losartan completely blocked Ang II-induced hypertension in both WT and PT-Nhe3-/- mice (P<0.01). However, inhibition of nitric oxide synthase with L-NG-Nitroarginine methyl ester had no effect on Ang II-induced hypertension in WT or PT-Nhe3-/- mice (not significant). Furthermore, Ang II-induced hypertension was significantly attenuated by an orally absorbable NHE3 inhibitor AVE0657. In conclusion, NHE3 in the proximal tubules of the kidney may be a therapeutical target in hypertension induced by Ang II or with increased NHE3 expression in the proximal tubules.
Collapse
Affiliation(s)
- Xiao C Li
- From the Department of Pharmacology and Toxicology (X.C.L., D.Z., X.C., X. Zheng, C.Z., J.Z., J.L.Z.), University of Mississippi Medical Center, Jackson
- Division of Nephrology, Department of Medicine (X.C.L., J.L.Z.), University of Mississippi Medical Center, Jackson
| | - Dongmin Zhu
- From the Department of Pharmacology and Toxicology (X.C.L., D.Z., X.C., X. Zheng, C.Z., J.Z., J.L.Z.), University of Mississippi Medical Center, Jackson
- Department of Anesthesiology, Shenzhen Far East Obstetrics and Gynecology Hospital, China (D.Z.)
| | - Xu Chen
- From the Department of Pharmacology and Toxicology (X.C.L., D.Z., X.C., X. Zheng, C.Z., J.Z., J.L.Z.), University of Mississippi Medical Center, Jackson
| | - Xiaowen Zheng
- From the Department of Pharmacology and Toxicology (X.C.L., D.Z., X.C., X. Zheng, C.Z., J.Z., J.L.Z.), University of Mississippi Medical Center, Jackson
- Department of Emergency Medicine, Second Affiliated Hospital, Guangxi Medical University, Nanning, China (X. Zheng, C.Z., J.Z.)
| | - Chunling Zhao
- From the Department of Pharmacology and Toxicology (X.C.L., D.Z., X.C., X. Zheng, C.Z., J.Z., J.L.Z.), University of Mississippi Medical Center, Jackson
- Department of Emergency Medicine, Second Affiliated Hospital, Guangxi Medical University, Nanning, China (X. Zheng, C.Z., J.Z.)
| | - Jianfeng Zhang
- From the Department of Pharmacology and Toxicology (X.C.L., D.Z., X.C., X. Zheng, C.Z., J.Z., J.L.Z.), University of Mississippi Medical Center, Jackson
- Department of Emergency Medicine, Second Affiliated Hospital, Guangxi Medical University, Nanning, China (X. Zheng, C.Z., J.Z.)
| | - Manoocher Soleimani
- Division of Nephrology and Hypertension, Department of Internal Medicine, The University of Cincinnati College of Medicine, OH (M.S.)
| | - Isabelle Rubera
- Laboratoire de Physiomédecine Moléculaire, LP2M, UMR-CNRS 7370, Université Côte d'Azur, Nice Cedex 2, France (I.R., M.T.)
| | - Michel Tauc
- Laboratoire de Physiomédecine Moléculaire, LP2M, UMR-CNRS 7370, Université Côte d'Azur, Nice Cedex 2, France (I.R., M.T.)
| | - Xinchun Zhou
- Department of Pathology (X. Zhou), University of Mississippi Medical Center, Jackson
| | - Jia L Zhuo
- From the Department of Pharmacology and Toxicology (X.C.L., D.Z., X.C., X. Zheng, C.Z., J.Z., J.L.Z.), University of Mississippi Medical Center, Jackson
- Division of Nephrology, Department of Medicine (X.C.L., J.L.Z.), University of Mississippi Medical Center, Jackson
| |
Collapse
|
20
|
Poulsen SB, Fenton RA. K
+
and the renin–angiotensin–aldosterone system: new insights into their role in blood pressure control and hypertension treatment. J Physiol 2019; 597:4451-4464. [DOI: 10.1113/jp276844] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/17/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Søren B. Poulsen
- Department of BiomedicineAarhus University Aarhus DK‐8000 Denmark
| | - Robert A. Fenton
- Department of BiomedicineAarhus University Aarhus DK‐8000 Denmark
| |
Collapse
|
21
|
Koizumi M, Ueda K, Niimura F, Nishiyama A, Yanagita M, Saito A, Pastan I, Fujita T, Fukagawa M, Matsusaka T. Podocyte Injury Augments Intrarenal Angiotensin II Generation and Sodium Retention in a Megalin-Dependent Manner. Hypertension 2019; 74:509-517. [PMID: 31352823 DOI: 10.1161/hypertensionaha.118.12352] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have previously shown that podocyte injury increases the glomerular filtration of liver-derived Agt (angiotensinogen) and the generation of intrarenal Ang II (angiotensin II) and that the filtered Agt is reabsorbed by proximal tubules in a manner dependent on megalin. In the present study, we aimed to study the role of megalin in the generation of renal Ang II and sodium handling during nephrotic syndrome. We generated proximal tubule-specific megalin KO (knockout) mice and crossed these animals with NEP25 mice, in which podocyte-specific injury can be induced by injection of the immunotoxin LMB2. Without podocyte injury, renal Agt staining was markedly diminished and urinary Agt increased in KO mice. However, renal Ang II was similar between KO and control mice on average: 117 (95% CI, 101-134) versus 101 (95% CI, 68-133) fmol/g tissue. We next tested the effect of megalin KO on intrarenal Ang II generation with podocyte injury. Control NEP25 mice showed markedly increased renal Agt staining and renal Ang II levels: 450 (336-565) fmol/g tissue. Megalin KO/NEP25 mice showed markedly diminished Agt reabsorption and attenuated renal Ang II: 199 (156-242) fmol/g tissue (P<0.001). Compared with control NEP25 mice, megalin KO/NEP25 mice excreted 5-fold more sodium in the urine. Western blot analysis showed that megalin KO decreased NHE3 and the cleaved α and γ forms of Epithelial Na Channel. These data indicate that Agt reabsorbed by proximal tubules via megalin in nephrotic syndrome is converted to Ang II, which may contribute to sodium retention and edema formation by activating NHE3 and Epithelial Na Channel.
Collapse
Affiliation(s)
- Masahiro Koizumi
- From the Department of Nephrology, Endocrinology and Metabolism (M.K., M.F.), Tokai University School of Medicine, Isehara, Japan.,Department of Basic Medicine (M.K., T.M.), Tokai University School of Medicine, Isehara, Japan
| | - Kohei Ueda
- Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., T.F.)
| | - Fumio Niimura
- Department of Pediatrics (F.N.), Tokai University School of Medicine, Isehara, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University School of Medicine, Miki-cho, Kita-gun, Japan (A.N.)
| | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Japan (M.Y.)
| | - Akihiko Saito
- Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Japan (A.S.)
| | - Ira Pastan
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institutes, National Institutes of Health, Bethesda, MD (I.P.)
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., T.F.)
| | - Masafumi Fukagawa
- From the Department of Nephrology, Endocrinology and Metabolism (M.K., M.F.), Tokai University School of Medicine, Isehara, Japan
| | - Taiji Matsusaka
- Department of Basic Medicine (M.K., T.M.), Tokai University School of Medicine, Isehara, Japan.,Institute of Medical Sciences, Tokai University, Isehara, Japan (T.M.)
| |
Collapse
|
22
|
Dolomatov S, Zukow W, Novikov N, Markaryan A, Eremeeva E. EXPRESSION OF THE RENIN-ANGIOTENSIN SYSTEM COMPONENTS IN ONCOLOGIC DISEASES. Acta Clin Croat 2019; 58:354-364. [PMID: 31819334 PMCID: PMC6884393 DOI: 10.20471/acc.2019.58.02.21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The literature devoted to changes in the expression of the renin-angiotensin system (RAS) proteins of cancer cells was analyzed. The dynamics of RAS protein expression in malignant tumors and the possible role of epigenetic mechanisms in these processes are briefly reviewed. Through research of the epigenetic mechanisms in cancer, principally new techniques for their correction based on the use of selective regulatory systems of covalent modification of histone proteins (for example, deacetylase inhibitor) and microRNA synthesis technologies have been developed. Literature data show promising pharmacological correction of epigenetic modification of chromatin in the treatment of cancer.
Collapse
Affiliation(s)
| | - Walery Zukow
- 1Department of Medical Biology, Medical Academy SI Georgievsky, Crimea Federal University, Simferopol, Russian Federation jurisdiction; 2Faculty of Earth, Nicolaus Copernicus University, Toruń, Poland; 3A. Tsyb Medical Radiological Research Center, branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Obninsk, Kaluga Region, Russian Federation
| | - Nikolay Novikov
- 1Department of Medical Biology, Medical Academy SI Georgievsky, Crimea Federal University, Simferopol, Russian Federation jurisdiction; 2Faculty of Earth, Nicolaus Copernicus University, Toruń, Poland; 3A. Tsyb Medical Radiological Research Center, branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Obninsk, Kaluga Region, Russian Federation
| | - Alexandra Markaryan
- 1Department of Medical Biology, Medical Academy SI Georgievsky, Crimea Federal University, Simferopol, Russian Federation jurisdiction; 2Faculty of Earth, Nicolaus Copernicus University, Toruń, Poland; 3A. Tsyb Medical Radiological Research Center, branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Obninsk, Kaluga Region, Russian Federation
| | - Elena Eremeeva
- 1Department of Medical Biology, Medical Academy SI Georgievsky, Crimea Federal University, Simferopol, Russian Federation jurisdiction; 2Faculty of Earth, Nicolaus Copernicus University, Toruń, Poland; 3A. Tsyb Medical Radiological Research Center, branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Obninsk, Kaluga Region, Russian Federation
| |
Collapse
|
23
|
Malmberg P, Norén JG, Bernin D. Molecular insights into hypomineralized enamel. Eur J Oral Sci 2019; 127:340-346. [DOI: 10.1111/eos.12619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Per Malmberg
- Department of Chemistry and Chemical Engineering Chalmers University of Technology Gothenburg Sweden
| | - Jörgen G. Norén
- Department of Pediatric Dentistry Institute of Odontology Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
| | - Diana Bernin
- Department of Chemistry and Chemical Engineering Chalmers University of Technology Gothenburg Sweden
- Swedish NMR Centre University of Gothenburg Gothenburg Sweden
| |
Collapse
|
24
|
Gonzalez-Vicente A, Saez F, Monzon CM, Asirwatham J, Garvin JL. Thick Ascending Limb Sodium Transport in the Pathogenesis of Hypertension. Physiol Rev 2019; 99:235-309. [PMID: 30354966 DOI: 10.1152/physrev.00055.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The thick ascending limb plays a key role in maintaining water and electrolyte balance. The importance of this segment in regulating blood pressure is evidenced by the effect of loop diuretics or local genetic defects on this parameter. Hormones and factors produced by thick ascending limbs have both autocrine and paracrine effects, which can extend prohypertensive signaling to other structures of the nephron. In this review, we discuss the role of the thick ascending limb in the development of hypertension, not as a sole participant, but one that works within the rich biological context of the renal medulla. We first provide an overview of the basic physiology of the segment and the anatomical considerations necessary to understand its relationship with other renal structures. We explore the physiopathological changes in thick ascending limbs occurring in both genetic and induced animal models of hypertension. We then discuss the racial differences and genetic defects that affect blood pressure in humans through changes in thick ascending limb transport rates. Throughout the text, we scrutinize methodologies and discuss the limitations of research techniques that, when overlooked, can lead investigators to make erroneous conclusions. Thus, in addition to advancing an understanding of the basic mechanisms of physiology, the ultimate goal of this work is to understand our research tools, to make better use of them, and to contextualize research data. Future advances in renal hypertension research will require not only collection of new experimental data, but also integration of our current knowledge.
Collapse
Affiliation(s)
| | - Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Casandra M Monzon
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jessica Asirwatham
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| |
Collapse
|
25
|
Forrester SJ, Booz GW, Sigmund CD, Coffman TM, Kawai T, Rizzo V, Scalia R, Eguchi S. Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology. Physiol Rev 2018; 98:1627-1738. [PMID: 29873596 DOI: 10.1152/physrev.00038.2017] [Citation(s) in RCA: 621] [Impact Index Per Article: 103.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT1R) is believed to mediate most functions of ANG II in the system. AT1R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT1R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT1R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.
Collapse
Affiliation(s)
- Steven J Forrester
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - George W Booz
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Curt D Sigmund
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Thomas M Coffman
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Tatsuo Kawai
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Victor Rizzo
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Rosario Scalia
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Satoru Eguchi
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| |
Collapse
|
26
|
Angiotensin II-induced hypertension in rats is only transiently accompanied by lower renal oxygenation. Sci Rep 2018; 8:16342. [PMID: 30397212 PMCID: PMC6218546 DOI: 10.1038/s41598-018-34211-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 10/09/2018] [Indexed: 02/08/2023] Open
Abstract
Activation of the renin-angiotensin system may initiate chronic kidney disease. We hypothesised that renal hypoxia is a consequence of hemodynamic changes induced by angiotensin II and occurs prior to development of severe renal damage. Male Sprague-Dawley rats were infused continuously with angiotensin II (350 ng/kg/min) for 8 days. Mean arterial pressure (n = 5), cortical (n = 6) and medullary (n = 7) oxygenation (pO2) were continuously recorded by telemetry and renal tissue injury was scored. Angiotensin II increased arterial pressure gradually to 150 ± 18 mmHg. This was associated with transient reduction of oxygen levels in renal cortex (by 18 ± 2%) and medulla (by 17 ± 6%) at 10 ± 2 and 6 ± 1 hours, respectively after starting infusion. Thereafter oxygen levels normalised to pre-infusion levels and were maintained during the remainder of the infusion period. In rats receiving angiotensin II, adding losartan to drinking water (300 mg/L) only induced transient increase in renal oxygenation, despite normalisation of arterial pressure. In rats, renal hypoxia is only a transient phenomenon during initiation of angiotensin II-induced hypertension.
Collapse
|
27
|
Packer M. Role of the sodium-hydrogen exchanger in mediating the renal effects of drugs commonly used in the treatment of type 2 diabetes. Diabetes Obes Metab 2018; 20:800-811. [PMID: 29227582 DOI: 10.1111/dom.13191] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/07/2017] [Accepted: 12/07/2017] [Indexed: 01/19/2023]
Abstract
Diabetes is characterized by increased activity of the sodium-hydrogen exchanger (NHE) in the glomerulus and renal tubules, which contributes importantly to the development of nephropathy. Despite the established role played by the exchanger in experimental studies, it has not been specifically targeted by those seeking to develop novel pharmacological treatments for diabetes. This review demonstrates that many existing drugs that are commonly prescribed to patients with diabetes act on the NHE1 and NHE3 isoforms in the kidney. This action may explain their effects on sodium excretion, albuminuria and the progressive decline of glomerular function in clinical trials; these responses cannot be readily explained by the influence of these drugs on blood glucose. Agents that may affect the kidney in diabetes by virtue of an action on NHE include: (1) insulin and insulin sensitizers; (2) incretin-based agents; (3) sodium-glucose cotransporter 2 inhibitors; (4) antagonists of the renin-angiotensin system (angiotensin converting-enzyme inhibitors, angiotensin receptor blockers and angiotensin receptor neprilysin inhibitors); and (5) inhibitors of aldosterone action and cholesterol synthesis (spironolactone, amiloride and statins). The renal effects of each of these drug classes in patients with type 2 diabetes may be related to a single shared biological mechanism.
Collapse
Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas
| |
Collapse
|
28
|
Hyndman KA, Mironova EV, Giani JF, Dugas C, Collins J, McDonough AA, Stockand JD, Pollock JS. Collecting Duct Nitric Oxide Synthase 1ß Activation Maintains Sodium Homeostasis During High Sodium Intake Through Suppression of Aldosterone and Renal Angiotensin II Pathways. J Am Heart Assoc 2017; 6:e006896. [PMID: 29066445 PMCID: PMC5721879 DOI: 10.1161/jaha.117.006896] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 07/27/2017] [Indexed: 12/24/2022]
Abstract
BACKGROUND During high sodium intake, the renin-angiotensin-aldosterone system is downregulated and nitric oxide signaling is upregulated in order to remain in sodium balance. Recently, we showed that collecting duct nitric oxide synthase 1β is critical for fluid-electrolyte balance and subsequently blood pressure regulation during high sodium feeding. The current study tested the hypothesis that high sodium activation of the collecting duct nitric oxide synthase 1β pathway is critical for maintaining sodium homeostasis and for the downregulation of the renin-angiotensin-aldosterone system-epithelial sodium channel axis. METHODS AND RESULTS Male control and collecting duct nitric oxide synthase 1β knockout (CDNOS1KO) mice were placed on low, normal, and high sodium diets for 1 week. In response to the high sodium diet, plasma sodium was significantly increased in control mice and to a significantly greater level in CDNOS1KO mice. CDNOS1KO mice did not suppress plasma aldosterone in response to the high sodium diet, which may be partially explained by increased adrenal AT1R expression. Plasma renin concentration was appropriately suppressed in both genotypes. Furthermore, CDNOS1KO mice had significantly higher intrarenal angiotensin II with high sodium diet, although intrarenal angiotensinogen levels and angiotensin-converting enzyme activity were similar between knockout mice and controls. In agreement with inappropriate renin-angiotensin-aldosterone system activation in the CDNOS1KO mice on a high sodium diet, epithelial sodium channel activity and sodium transporter abundance were significantly higher compared with controls. CONCLUSIONS These data demonstrate that high sodium activation of collecting duct nitric oxide synthase 1β signaling induces suppression of systemic and intrarenal renin-angiotensin-aldosterone system, thereby modulating epithelial sodium channel and other sodium transporter abundance and activity to maintain sodium homeostasis.
Collapse
Affiliation(s)
- Kelly A Hyndman
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, AL
| | - Elena V Mironova
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, TX
| | - Jorge F Giani
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Courtney Dugas
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, AL
| | - Jessika Collins
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, AL
| | - Alicia A McDonough
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - James D Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, TX
| | - Jennifer S Pollock
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, AL
| |
Collapse
|
29
|
Li XC, Zhuo JL. Recent Updates on the Proximal Tubule Renin-Angiotensin System in Angiotensin II-Dependent Hypertension. Curr Hypertens Rep 2017; 18:63. [PMID: 27372447 DOI: 10.1007/s11906-016-0668-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
It is well recognized that the renin-angiotensin system (RAS) exists not only as circulating, paracrine (cell to cell), but also intracrine (intracellular) system. In the kidney, however, it is difficult to dissect the respective contributions of circulating RAS versus intrarenal RAS to the physiological regulation of proximal tubular Na(+) reabsorption and hypertension. Here, we review recent studies to provide an update in this research field with a focus on the proximal tubular RAS in angiotensin II (ANG II)-induced hypertension. Careful analysis of available evidence supports the hypothesis that both local synthesis or formation and AT1 (AT1a) receptor- and/or megalin-mediated uptake of angiotensinogen (AGT), ANG I and ANG II contribute to high levels of ANG II in the proximal tubules of the kidney. Under physiological conditions, nearly all major components of the RAS including AGT, prorenin, renin, ANG I, and ANG II would be filtered by the glomerulus and taken up by the proximal tubules. In ANG II-dependent hypertension, the expression of AGT, prorenin, and (pro)renin receptors, and angiotensin-converting enzyme (ACE) is upregulated rather than downregulated in the kidney. Furthermore, hypertension damages the glomerular filtration barrier, which augments the filtration of circulating AGT, prorenin, renin, ANG I, and ANG II and their uptake in the proximal tubules. Together, increased local ANG II formation and augmented uptake of circulating ANG II in the proximal tubules, via activation of AT1 (AT1a) receptors and Na(+)/H(+) exchanger 3, may provide a powerful feedforward mechanism for promoting Na(+) retention and the development of ANG II-induced hypertension.
Collapse
Affiliation(s)
- Xiao C Li
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, 2500 North State Street, Jackson, MS, 39216-4505, USA
| | - Jia L Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, 2500 North State Street, Jackson, MS, 39216-4505, USA.
| |
Collapse
|
30
|
Li J, Hatano R, Xu S, Wan L, Yang L, Weinstein AM, Palmer L, Wang T. Gender difference in kidney electrolyte transport. I. Role of AT 1a receptor in thiazide-sensitive Na +-Cl - cotransporter activity and expression in male and female mice. Am J Physiol Renal Physiol 2017; 313:F505-F513. [PMID: 28566500 DOI: 10.1152/ajprenal.00087.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/11/2017] [Accepted: 05/30/2017] [Indexed: 11/22/2022] Open
Abstract
We studied gender differences in Na+-Cl- cotransporter (NCC) activity and expression in wild-type (WT) and AT1a receptor knockout (KO) mice. In renal clearance experiments, urine volume (UV), glomerular filtration rate, absolute Na+ (ENa) and K+ (EK), and fractional Na+ (FENa) and K+ excretion were measured and compared at peak changes after bolus intravenous injection of hydrochlorothiazide (HCTZ; 30 mg/kg). In WT, females responded more strongly than males to HCTZ, with larger fractional increases of UV (7.8- vs. 3.4-fold), ENa (11.7- vs. 5.7-fold), FENa (7.9- vs. 4.9-fold), and EK (2.8- vs. 1.4-fold). In contrast, there were no gender differences in the responses to the diuretic in KO mice; HCTZ produced greater effects on male KO than on WT but similar effects on females. In WT, total (tNCC) and phosphorylated (pNCC) NCC protein expressions were 1.8- and 4.6-fold higher in females compared with males (P < 0.05), consistent with the larger response to HCTZ. In KO mice, tNCC and pNCC increased significantly in males to levels not different from those in females. There were no gender differences in the expression of the Na+/H+ exchanger (NHE3) in WT; NHE3 protein decreased to similar extents in male and female KO animals, suggesting AT1a-mediated NHE3 expression in proximal tubules. The resulting increase in delivery of NaCl to the distal nephron may underlie increased NCC expression and activity in mice lacking the AT1a receptor.
Collapse
Affiliation(s)
- Jing Li
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut.,Department of Basic Medical Science, Chengdu Medical College, Chengdu, China
| | - Ryo Hatano
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Shuhua Xu
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Laxiang Wan
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Lei Yang
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York; and
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York; and
| | - Lawrence Palmer
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York; and
| | - Tong Wang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut;
| |
Collapse
|
31
|
Fenton RA, Poulsen SB, de la Mora Chavez S, Soleimani M, Dominguez Rieg JA, Rieg T. Renal tubular NHE3 is required in the maintenance of water and sodium chloride homeostasis. Kidney Int 2017; 92:397-414. [PMID: 28385297 DOI: 10.1016/j.kint.2017.02.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 01/25/2017] [Accepted: 02/02/2017] [Indexed: 11/30/2022]
Abstract
The sodium/proton exchanger isoform 3 (NHE3) is expressed in the intestine and the kidney, where it facilitates sodium (re)absorption and proton secretion. The importance of NHE3 in the kidney for sodium chloride homeostasis, relative to the intestine, is unknown. Constitutive tubule-specific NHE3 knockout mice (NHE3loxloxCre) did not show significant differences compared to control mice in body weight, blood pH or bicarbonate and plasma sodium, potassium, or aldosterone levels. Fluid intake, urinary flow rate, urinary sodium/creatinine, and pH were significantly elevated in NHE3loxloxCre mice, while urine osmolality and GFR were significantly lower. Water deprivation revealed a small urinary concentrating defect in NHE3loxloxCre mice on a control diet, exaggerated on low sodium chloride. Ten days of low or high sodium chloride diet did not affect plasma sodium in control mice; however, NHE3loxloxCre mice were susceptible to low sodium chloride (about -4 mM) or high sodium chloride intake (about +2 mM) versus baseline, effects without differences in plasma aldosterone between groups. Blood pressure was significantly lower in NHE3loxloxCre mice and was sodium chloride sensitive. In control mice, the expression of the sodium/phosphate co-transporter Npt2c was sodium chloride sensitive. However, lack of tubular NHE3 blunted Npt2c expression. Alterations in the abundances of sodium/chloride cotransporter and its phosphorylation at threonine 58 as well as the abundances of the α-subunit of the epithelial sodium channel, and its cleaved form, were also apparent in NHE3loxloxCre mice. Thus, renal NHE3 is required to maintain blood pressure and steady-state plasma sodium levels when dietary sodium chloride intake is modified.
Collapse
Affiliation(s)
- Robert A Fenton
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Søren B Poulsen
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark; VA San Diego Healthcare System, San Diego, California, USA
| | | | - Manoocher Soleimani
- Department of Medicine, University of Cincinnati, Cincinnati, Ohio, USA; Research Services, Veterans Affairs Medical Center, Cincinnati, Ohio, USA
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA.
| |
Collapse
|
32
|
Frindt G, Yang L, Uchida S, Weinstein AM, Palmer LG. Responses of distal nephron Na + transporters to acute volume depletion and hyperkalemia. Am J Physiol Renal Physiol 2017; 313:F62-F73. [PMID: 28356292 DOI: 10.1152/ajprenal.00668.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/21/2017] [Accepted: 03/21/2017] [Indexed: 01/01/2023] Open
Abstract
We assessed effects of acute volume reductions induced by administration of diuretics in rats. Direct block of Na+ transport produced changes in urinary electrolyte excretion. Adaptations to these effects appeared as alterations in the expression of protein for the distal nephron Na+ transporters NCC and ENaC. Two hours after a single injection of furosemide (6 mg/kg) or hydrochlorothiazide (HCTZ; 30 mg/kg) Na+ and K+ excretion increased but no changes in the content of activated forms of NCC (phosphorylated on residue T53) or ENaC (cleaved γ-subunit) were detected. In contrast, amiloride (0.6 mg/kg) evoked a similar natriuresis that coincided with decreased pT53NCC and increased cleaved γENaC. Alterations in posttranslational membrane protein processing correlated with an increase in plasma K+ of 0.6-0.8 mM. Decreased pT53NCC occurred within 1 h after amiloride injection, whereas changes in γENaC were slower and were blocked by the mineralocorticoid receptor antagonist spironolactone. Increased γENaC cleavage correlated with elevation of the surface expression of the subunit as assessed by in situ biotinylation. Na depletion induced by 2 h of furosemide or HCTZ treatment increases total NCC expression without affecting ENaC protein. However, restriction of Na intake for 10 h (during the day) or 18 h (overnight) increased the abundance of both total NCC and of cleaved α- and γENaC. We conclude that the kidneys respond acutely to hyperkalemic challenges by decreasing the activity of NCC while increasing that of ENaC. They respond to hypovolemia more slowly, increasing Na+ reabsorptive capacities of both of these transporters.
Collapse
Affiliation(s)
- Gustavo Frindt
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York
| | - Lei Yang
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York.,Department of Physiology, Harbin University School of Medicine, Harbin, China; and
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York.,Department of Medicine, Weill Cornell Medical College, New York, New York
| | - Lawrence G Palmer
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York;
| |
Collapse
|
33
|
Chu PL, Gigliotti JC, Cechova S, Bodonyi-Kovacs G, Chan F, Ralph DL, Howell N, Kalantari K, Klibanov AL, Carey RM, McDonough AA, Le TH. Renal Collectrin Protects against Salt-Sensitive Hypertension and Is Downregulated by Angiotensin II. J Am Soc Nephrol 2017; 28:1826-1837. [PMID: 28062568 DOI: 10.1681/asn.2016060675] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022] Open
Abstract
Collectrin, encoded by the Tmem27 gene, is a transmembrane glycoprotein with approximately 50% homology with angiotensin converting enzyme 2, but without a catalytic domain. Collectrin is most abundantly expressed in the kidney proximal tubule and collecting duct epithelia, where it has an important role in amino acid transport. Collectrin is also expressed in endothelial cells throughout the vasculature, where it regulates L-arginine uptake. We previously reported that global deletion of collectrin leads to endothelial dysfunction, augmented salt sensitivity, and hypertension. Here, we performed kidney crosstransplants between wild-type (WT) and collectrin knockout (Tmem27Y/- ) mice to delineate the specific contribution of renal versus extrarenal collectrin on BP regulation and salt sensitivity. On a high-salt diet, WT mice with Tmem27Y/- kidneys had the highest systolic BP and were the only group to exhibit glomerular mesangial hypercellularity. Additional studies showed that, on a high-salt diet, Tmem27Y/- mice had lower renal blood flow, higher abundance of renal sodium-hydrogen antiporter 3, and lower lithium clearance than WT mice. In WT mice, administration of angiotensin II for 2 weeks downregulated collectrin expression in a type 1 angiotensin II receptor-dependent manner. This downregulation coincided with the onset of hypertension, such that WT and Tmem27Y/- mice had similar levels of hypertension after 2 weeks of angiotensin II administration. Altogether, these data suggest that salt sensitivity is determined by intrarenal collectrin, and increasing the abundance or activity of collectrin may have therapeutic benefits in the treatment of hypertension and salt sensitivity.
Collapse
Affiliation(s)
| | - Joseph C Gigliotti
- Division of Nephrology.,Department of Integrated Physiology and Pharmacology, Liberty University College of Osteopathic Medicine, Lynchburg, Virginia; and
| | | | | | | | - Donna Lee Ralph
- Department of Cell and Neurobiology, University of Southern California, Keck School of Medicine, Los Angeles, California
| | - Nancy Howell
- Division of Endocrinology, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | | | | | - Robert M Carey
- Division of Endocrinology, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - Alicia A McDonough
- Department of Cell and Neurobiology, University of Southern California, Keck School of Medicine, Los Angeles, California
| | | |
Collapse
|
34
|
Veiras LC, Han J, Ralph DL, McDonough AA. Potassium Supplementation Prevents Sodium Chloride Cotransporter Stimulation During Angiotensin II Hypertension. Hypertension 2016; 68:904-12. [PMID: 27600183 DOI: 10.1161/hypertensionaha.116.07389] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/27/2016] [Indexed: 01/06/2023]
Abstract
Angiotensin II (AngII) hypertension increases distal tubule Na-Cl cotransporter (NCC) abundance and phosphorylation (NCCp), as well as epithelial Na(+) channel abundance and activating cleavage. Acutely raising plasma [K(+)] by infusion or ingestion provokes a rapid decrease in NCCp that drives a compensatory kaliuresis. The first aim tested whether acutely raising plasma [K(+)] with a single 3-hour 2% potassium meal would lower NCCp in Sprague-Dawley rats after 14 days of AngII (400 ng/kg per minute). The potassium-rich meal neither decreased NCCp nor increased K(+) excretion. AngII-infused rats exhibited lower plasma [K(+)] versus controls (3.6±0.2 versus 4.5±0.1 mmol/L; P<0.05), suggesting that AngII-mediated epithelial Na(+) channel activation provokes K(+) depletion. The second aim tested whether doubling dietary potassium intake from 1% (A1K) to 2% (A2K) would prevent K(+) depletion during AngII infusion and, thus, prevent NCC accumulation. A2K-fed rats exhibited normal plasma [K(+)] and 2-fold higher K(+) excretion and plasma [aldosterone] versus A1K. In A1K rats, NCC, NCCpS71, and NCCpT53 abundance increased 1.5- to 3-fold versus controls (P<0.05). The rise in NCC and NCCp abundance was prevented in the A2K rats, yet blood pressure did not significantly decrease. Epithelial Na(+) channel subunit abundance and cleavage increased 1.5- to 3-fold in both A1K and A2K; ROMK (renal outer medulla K(+) channel abundance) abundance was unaffected by AngII or dietary K(+) In summary, the accumulation and phosphorylation of NCC seen during chronic AngII infusion hypertension is likely secondary to potassium deficiency driven by epithelial Na(+) channel stimulation.
Collapse
Affiliation(s)
- Luciana C Veiras
- From the Department of Cell and Neurobiology, Keck School of Medicine of USC, Los Angeles, CA
| | - Jiyang Han
- From the Department of Cell and Neurobiology, Keck School of Medicine of USC, Los Angeles, CA
| | - Donna L Ralph
- From the Department of Cell and Neurobiology, Keck School of Medicine of USC, Los Angeles, CA
| | - Alicia A McDonough
- From the Department of Cell and Neurobiology, Keck School of Medicine of USC, Los Angeles, CA.
| |
Collapse
|
35
|
He P, Zhao L, No YR, Karvar S, Yun CC. The NHERF1 PDZ1 domain and IRBIT interact and mediate the activation of Na+/H+ exchanger 3 by ANG II. Am J Physiol Renal Physiol 2016; 311:F343-51. [PMID: 27279487 DOI: 10.1152/ajprenal.00247.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/01/2016] [Indexed: 11/22/2022] Open
Abstract
Na(+)/H(+) exchanger (NHE)3, a major Na(+) transporter in the luminal membrane of the proximal tubule, is subject to ANG II regulation in renal Na(+)/fluid absorption and blood pressure control. We have previously shown that inositol 1,4,5-trisphosphate receptor-binding protein released with inositol 1,4,5-trisphosphate (IRBIT) mediates ANG II-induced exocytosis of NHE3 in cultured proximal tubule epithelial cells. In searching for scaffold protein(s) that coordinates with IRBIT in NHE3 trafficking, we found that NHE regulatory factor (NHERF)1, NHE3, and IRBIT proteins were coexpressed in the same macrocomplexes and that loss of ANG II type 1 receptors decreased their expression in the renal brush-border membrane. We found that NHERF1 was required for ANG II-mediated forward trafficking and activation of NHE3 in cultured cells. ANG II induced a concomitant increase of NHERF1 interactions with NHE3 and IRBIT, which were abolished when the NHERF1 PDZ1 domain was removed. Overexpression of a yellow fluorescent protein-NHERF1 construct that lacks PDZ1, but not PDZ2, failed to exaggerate the ANG II-dependent increase of NHE3 expression in the apical membrane. Moreover, exogenous expression of PDZ1 exerted a dominant negative effect on NHE3 activation by ANG II. We further demonstrated that IRBIT was indispensable for the ANG II-provoked increase in NHERF1-NHE3 interactions and that phosphorylation of IRBIT at Ser(68) was necessary for the assembly of the NHEF1-IRBIT-NHE3 complex. Taken together, our findings suggest that NHERF1 mediates ANG II-induced activation of renal NHE3, which requires coordination between IRBIT and the NHERF1 PDZ1 domain in binding and transporting NHE3.
Collapse
Affiliation(s)
- Peijian He
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia;
| | - Luqing Zhao
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Department of Gastroenterology, Beijing Hospital of Traditional Chinese Medicine affiliated with Capital Medical University, Beijing, China
| | - Yi Ran No
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Serhan Karvar
- Division of Gastroenterology and Hepatology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - C Chris Yun
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Atlanta Veterans Affairs Medical Center, Decatur, Georgia; and Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia
| |
Collapse
|
36
|
Peng K, Lu X, Wang F, Nau A, Chen R, Zhou SF, Yang T. Collecting duct (pro)renin receptor targets ENaC to mediate angiotensin II-induced hypertension. Am J Physiol Renal Physiol 2016; 312:F245-F253. [PMID: 27122543 DOI: 10.1152/ajprenal.00178.2016] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/21/2016] [Indexed: 01/09/2023] Open
Abstract
The (pro)renin receptor (PRR) is abundantly expressed in the collecting duct (CD) and the expression is further induced by angiotensin II (ANG II). The present study was conducted to investigate the role of CD PRR during ANG II-induced hypertension and to further explore the underlying mechanism. Radiotelemetry demonstrated that a 1-wk ANG II infusion gradually and significantly induced hypertensive response in floxed mice and this response was significantly attenuated in mice lacking PRR in the CD (termed CD PRR KO). ANG II infusion in floxed mice increased urinary renin activity and selectively induced renal medullary α-epithelial sodium channel (α-ENaC) mRNA and protein expression, all of which were blunted in the null mice. In cultured mpkCCD cells grown in Transwells, transepithelial Na+ transport as measured by using a volt-ohmmeter was transiently stimulated by acute ANG II treatment, which was abolished by a PRR antagonist, PRO20. In a chronic setting, ANG II treatment induced α-ENaC mRNA expression in mpkCCD cells, which was similarly blocked by PRO20. Chronic intramedullary infusion of an ENaC inhibitor amiloride in rats significantly attenuated ANG II-induced hypertension. Overall, the present study suggests that CD PRR contributes to ANG II-induced hypertension at least partially via activation of renal medullary ENaC.
Collapse
Affiliation(s)
- Kexin Peng
- Institute of Hypertension, Sun Yat-Sen University School of Medicine, Guangzhou, China.,Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Xiaohan Lu
- Institute of Hypertension, Sun Yat-Sen University School of Medicine, Guangzhou, China.,Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Fei Wang
- Institute of Hypertension, Sun Yat-Sen University School of Medicine, Guangzhou, China.,Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Adam Nau
- Institute of Hypertension, Sun Yat-Sen University School of Medicine, Guangzhou, China
| | - Ren Chen
- Department of Internal Medicine, Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, Guangzhou, China; and
| | - Shu-Feng Zhou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, Florida
| | - Tianxin Yang
- Institute of Hypertension, Sun Yat-Sen University School of Medicine, Guangzhou, China; .,Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| |
Collapse
|