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Kim K, Nist KM, Puleo F, McKenna J, Wainford RD. Sex differences in dietary sodium evoked NCC regulation and blood pressure in male and female Sprague-Dawley, Dahl salt-resistant, and Dahl salt-sensitive rats. Am J Physiol Renal Physiol 2024; 327:F277-F289. [PMID: 38813592 DOI: 10.1152/ajprenal.00150.2023] [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: 05/31/2023] [Revised: 05/07/2024] [Accepted: 05/15/2024] [Indexed: 05/31/2024] Open
Abstract
Hypertension affects approximately one in two United States adults and sex plays an important role in the pathogenesis of hypertension. The Na+-Cl- cotransporter (NCC), regulated by a kinase network including with-no-lysine kinase (WNK)1 and WNK4, STE20/SPS1-related proline alanine-rich kinase (SPAK), and oxidative stress response 1 (OxSR1), is critical to Na+ reabsorption and blood pressure regulation. Dietary salt differentially modulates NCC in salt-sensitive and salt-resistant rats, in part by modulation of WNK/SPAK/OxSR1 signaling. In this study, we tested the hypothesis that sex-dependent differences in NCC regulation contribute to the development of the salt sensitivity of blood pressure using male and female Sprague-Dawley (SD), Dahl salt-resistant (DSR), and Dahl salt-sensitive (DSS) rats. In normotensive salt-resistant SD and DSR rats, a high-salt diet evoked significant decreases in NCC activity, expression, and phosphorylation. In males, these changes were associated with no change in WNK1 expression, a decrease in WNK4 levels, and suppression of SPAK/OxSR1 expression and phosphorylation. In contrast, in females, there was decreased NCC activity associated with suppression of SPAK/OxSR1 expression and phosphorylation. In hypertensive DSS rats, the ability of females to suppress NCC (in opposition to males) via a SPAK/OxSR1 mechanism likely contributes to their lower magnitude of salt-sensitive hypertension. Collectively, our findings support the existence of sex differences in male versus female rats with NCC regulation during dietary salt intake involving suppression of WNK4 expression in male rats only and the involvement of SPAK/OxSR1 signaling in both males and females.NEW & NOTEWORTHY NCC regulation is sex dependent. In normotensive male and female Sprague-Dawley and Dahl salt-resistant rats, which exhibit dietary Na+-evoked NCC suppression, male rats exhibit decreased WNK4 expression and decreased SPAK and OxSR1 levels, whereas female rats only suppress SPAK and OxSR1. In hypertensive Dahl salt-sensitive rats, the ability of females to suppress NCC (in opposition to males) via a SPAK/OxSR1 mechanism likely contributes to their lower magnitude of salt-sensitive hypertension.
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Affiliation(s)
- Kiyoung Kim
- Department of Pharmacology and Experimental Therapeutics, Whitaker Cardiovascular Institute, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts, United States
| | - Kayla M Nist
- Department of Anatomy and Neurobiology, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts, United States
| | - Franco Puleo
- Department of Pharmacology and Experimental Therapeutics, Whitaker Cardiovascular Institute, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts, United States
| | - James McKenna
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Richard D Wainford
- Department of Pharmacology and Experimental Therapeutics, Whitaker Cardiovascular Institute, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts, United States
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
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2
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Frame AA, Nist KM, Kim K, Puleo F, Moreira JD, Swaldi H, McKenna J, Wainford RD. Integrated renal and sympathetic mechanisms underlying the development of sex- and age-dependent hypertension and the salt sensitivity of blood pressure. GeroScience 2024:10.1007/s11357-024-01266-1. [PMID: 38976131 DOI: 10.1007/s11357-024-01266-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 06/25/2024] [Indexed: 07/09/2024] Open
Abstract
Aging is a non-modifiable understudied risk factor for hypertension. We hypothesized that sympathetically mediated activation of renal sodium reabsorption drives age-dependent hypertension and the salt sensitivity of blood pressure (BP). Using 3-, 8-, and 16-month-old male and female Sprague-Dawley rats as a model of normal aging, we assessed BP, indices of sympathetic tone, and the physiological responses to acute and chronic sodium challenge including sodium chloride cotransporter (NCC) regulation. The effects of renal nerve ablation and NCC antagonism were assessed in hypertensive male rats. We observed sex-dependent impaired renal sodium handling (24 h sodium balance (meq), male 3-month 0.36 ± 0.1 vs. 16-month 0.84 ± 0.2; sodium load excreted during 5% bodyweight isotonic saline volume expansion (%) male 3-month 77 ± 5 vs. 16-month 22 ± 8), hypertension (MAP (mmHg) male 3-month 123 ± 4 vs. 16-month 148 ± 6), and the salt sensitivity of BP in aged male, but not female, rats. Attenuated sympathoinhibitory afferent renal nerve (ARN) responses contributed to increased sympathetic tone and hypertension in male rats. Increased sympathetic tone contributes to renal sodium retention, in part through increased NCC activity via a dysfunctional with-no-lysine kinase-(WNK) STE20/SPS1-related proline/alanine-rich kinase signaling pathway, to drive hypertension and the salt sensitivity of BP in aged male rats. NCC antagonism and renal nerve ablation, which reduced WNK dysfunction and decreased NCC activity, attenuated age-dependent hypertension in male Sprague-Dawley rats. The contribution of an impaired sympathoinhibitory ARN reflex to sex- and age-dependent hypertension in an NCC-dependent manner, via an impaired WNK1/WNK4 dynamic, suggests this pathway as a mechanism-based target for the treatment of age-dependent hypertension.
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Affiliation(s)
- Alissa A Frame
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Kayla M Nist
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Kiyoung Kim
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Franco Puleo
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Jesse D Moreira
- Department of Health Sciences, Sargent College, Boston University, Boston, MA, USA
| | - Hailey Swaldi
- Division of Cardiology, Emory University School of Medicine, 1750 Haygood Drive, Atlanta, GA, N22030322, USA
| | - James McKenna
- Division of Cardiology, Emory University School of Medicine, 1750 Haygood Drive, Atlanta, GA, N22030322, USA
| | - Richard D Wainford
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA.
- Division of Cardiology, Emory University School of Medicine, 1750 Haygood Drive, Atlanta, GA, N22030322, USA.
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3
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Gkousioudi A, Razzoli M, Moreira JD, Wainford RD, Zhang Y. Renal denervation restores biomechanics of carotid arteries in a rat model of hypertension. Sci Rep 2024; 14:495. [PMID: 38177257 PMCID: PMC10767006 DOI: 10.1038/s41598-023-50816-8] [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: 08/17/2023] [Accepted: 12/26/2023] [Indexed: 01/06/2024] Open
Abstract
The prevalence of hypertension increases with aging and is associated with increased arterial stiffness. Resistant hypertension is presented when drug treatments fail to regulate a sustained increased blood pressure. Given that the mechanisms between the sympathetic nervous system and the kidney play an important role in blood regulation, renal denervation (RDN) has emerged as a therapeutic potential in resistant hypertension. In this study, we investigated the effects of RDN on the biomechanical response and microstructure of elastic arteries. Common carotid arteries (CCA) excised from 3-month, 8-month, and 8-month denervated rats were subjected to biaxial extension-inflation test. Our results showed that hypertension developed in the 8-month-old rats. The sustained elevated blood pressure resulted in arterial remodeling which was manifested as a significant stress increase in both axial and circumferential directions after 8 months. RDN had a favorable impact on CCAs with a restoration of stresses in values similar to control arteries at 3 months. After biomechanical testing, arteries were imaged under a multi-photon microscope to identify microstructural changes in extracellular matrix (ECM). Quantification of multi-photon images showed no significant alterations of the main ECM components, elastic and collagen fibers, indicating that arteries remained intact after RDN. Regardless of the experimental group, our microstructural analysis of the multi-photon images revealed that reorientation of the collagen fibers might be the main microstructural mechanism taking place during pressurization with their straightening happening during axial stretching.
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Affiliation(s)
- Anastasia Gkousioudi
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Margherita Razzoli
- Department of Biomedical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Jesse D Moreira
- Department of Pharmacology & Experimental Therapeutics, School of Medicine, Boston University Avedisian and Chobanian, Boston, MA, USA
| | - Richard D Wainford
- Department of Pharmacology & Experimental Therapeutics, School of Medicine, Boston University Avedisian and Chobanian, Boston, MA, USA.
- Division of Cardiology, School of Medicine, HSRB II, Emory University, 1750 Haygood Drive, Atlanta, GA, 30322, USA.
| | - Yanhang Zhang
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA.
- Department of Biomedical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA.
- Division of Materials Science & Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA.
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Gkousioudi A, Razzoli M, Moreira JD, Wainford RD, Zhang Y. Renal denervation restores biomechanics of carotid arteries in a rat model of hypertension. RESEARCH SQUARE 2023:rs.3.rs-3273236. [PMID: 37720022 PMCID: PMC10503847 DOI: 10.21203/rs.3.rs-3273236/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
The prevalence of hypertension increases with aging and is associated with increased arterial stiffness. Resistant hypertension is presented when drug treatments fail to regulate a sustained increased blood pressure. Given that the mechanisms between the sympathetic nervous system and the kidney play an important role in blood regulation, renal denervation (RDN) has emerged as a therapeutic potential in resistant hypertension. In this study, we investigated the effects of RDN on the biomechanical response and microstructure of elastic arteries. Common carotid arteries (CCA) were excised from 3-, 8- and 8-month-old denervated rats, and subjected to biaxial extension-inflation test. Our results showed that hypertension developed in the 8-month-old rats. The sustained elevated blood pressure resulted in arterial remodeling which was manifested as a significant stress increase in both axial and circumferential directions after 8 months. RDN had a favorable impact on CCAs with a restoration of stresses in values similar to control arteries at 3 months. After biomechanical testing, arteries were imaged under a multi-photon microscope to identify microstructural changes in extracellular matrix (ECM). Quantification of multi-photon images showed no significant alterations of the main ECM components, elastic and collagen fibers, indicating that arteries remained intact after RDN. Regardless of the experimental group, our microstructural analysis of the multi-photon images revealed that reorientation of the collagen fibers might be the main microstructural mechanism taking place during pressurization with their straightening happening during axial stretching.
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Affiliation(s)
| | | | - Jesse D Moreira
- Boston University Avedisian and Chobanian School of Medicine
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5
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Masenga SK, Kirabo A. Hypertensive heart disease: risk factors, complications and mechanisms. Front Cardiovasc Med 2023; 10:1205475. [PMID: 37342440 PMCID: PMC10277698 DOI: 10.3389/fcvm.2023.1205475] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/26/2023] [Indexed: 06/22/2023] Open
Abstract
Hypertensive heart disease constitutes functional and structural dysfunction and pathogenesis occurring primarily in the left ventricle, the left atrium and the coronary arteries due to chronic uncontrolled hypertension. Hypertensive heart disease is underreported and the mechanisms underlying its correlates and complications are not well elaborated. In this review, we summarize the current understanding of hypertensive heart disease, we discuss in detail the mechanisms associated with development and complications of hypertensive heart disease especially left ventricular hypertrophy, atrial fibrillation, heart failure and coronary artery disease. We also briefly highlight the role of dietary salt, immunity and genetic predisposition in hypertensive heart disease pathogenesis.
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Affiliation(s)
- Sepiso K. Masenga
- HAND Research Group, School of Medicine and Health Sciences, Mulungushi University, Livingstone Cam-Pus, Livingstone, Zambia
- School of Medicine, University of Zambia, Lusaka, Zambia
- Department of Medicine, Vanderbilt University Medical Centre, Nashville, TN, United States
| | - Annet Kirabo
- Department of Medicine, Vanderbilt University Medical Centre, Nashville, TN, United States
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Li Y, Anand-Srivastava MB. Role of Gi proteins in the regulation of blood pressure and vascular remodeling. Biochem Pharmacol 2023; 208:115384. [PMID: 36549460 DOI: 10.1016/j.bcp.2022.115384] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/08/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
Heterotrimeric guanine nucleotide regulatory proteins (G-proteins) through the activation of several signaling mechanisms including adenylyl cyclase/cAMP and phospholipase C (PLC)/phosphatidyl inositol (PI) turnover. regulate a variety of cellular functions, including vascular reactivity, proliferation and hypertrophy of VSMC. Activity of adenylyl cyclase is regulated by two G proteins, stimulatory (Gsα) and inhibitory (Giα). Gsα stimulates adenylyl cyclase activity and increases the levels of cAMP, whereas Giα inhibits the activity of adenylyl cyclase and results in the reduction of cAMP levels. Abnormalities in Giα protein expression and associated adenylyl cyclase\cAMP levels result in the impaired cellular functions and contribute to various pathological states including hypertension. The expression of Giα proteins is enhanced in various tissues including heart, kidney, aorta and vascular smooth muscle cells (VSMC) from genetic (spontaneously hypertensive rats (SHR)) and experimentally - induced hypertensive rats and contribute to the pathogenesis of hypertension. In addition, the enhanced expression of Giα proteins exhibited by VSMC from SHR is also implicated in the hyperproliferation and hypertrophy, the two key players contributing to vascular remodelling in hypertension. The enhanced levels of endogenous vasoactive peptides including angiotensin II (Ang II), endothelin-1 (ET-1) and growth factors contribute to the overexpression of Giα proteins in VSMC from SHR. In addition, enhanced oxidative stress, activation of c-Src, growth factor receptor transactivation and MAP kinase/PI3kinase signaling also contribute to the augmented expression of Giα proteins in VSMC from SHR. This review summarizes the role of Giα proteins, and the underlying molecular mechanisms implicated in the regulation of high blood pressure and vascular remodelling.
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Affiliation(s)
- Yuan Li
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Madhu B Anand-Srivastava
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada.
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Amraei R, Moreira JD, Wainford RD. Central Gαi 2 Protein Mediated Neuro-Hormonal Control of Blood Pressure and Salt Sensitivity. Front Endocrinol (Lausanne) 2022; 13:895466. [PMID: 35837296 PMCID: PMC9275552 DOI: 10.3389/fendo.2022.895466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
Hypertension, a major public health issue, is estimated to contribute to 10% of all deaths worldwide. Further, the salt sensitivity of blood pressure is a critical risk factor for the development of hypertension. The hypothalamic paraventricular nucleus (PVN) coordinates neuro-hormonal responses to alterations in plasma sodium and osmolality and multiple G Protein-Coupled Receptors (GPCRs) are involved in fluid and electrolyte homeostasis. In acute animal studies, our laboratory has shown that central Gαi/o subunit protein signal transduction mediates hypotensive and bradycardic responses and that Gz/q, proteins mediate the release of arginine vasopressin (AVP) and subsequent aquaretic responses to acute pharmacological stimuli. Extending these studies, our laboratory has shown that central Gαi2 proteins selectively mediate the hypotensive, sympathoinhibitory and natriuretic responses to acute pharmacological activation of GPCRs and in response to acute physiological challenges to fluid and electrolyte balance. In addition, following chronically elevated dietary sodium intake, salt resistant rats demonstrate site-specific and subunit-specific upregulation of Gαi2 proteins in the PVN, resulting in sympathoinhibition and normotension. In contrast, chronic dietary sodium intake in salt sensitive animals, which fail to upregulate PVN Gαi2 proteins, results in the absence of dietary sodium-evoked sympathoinhibition and salt sensitive hypertension. Using in situ hybridization, we observed that Gαi2 expressing neurons in parvocellular division of the PVN strongly (85%) colocalize with GABAergic neurons. Our data suggest that central Gαi2 protein-dependent responses to an acute isotonic volume expansion (VE) and elevated dietary sodium intake are mediated by the peripheral sensory afferent renal nerves and do not depend on the anteroventral third ventricle (AV3V) sodium sensitive region or the actions of central angiotensin II type 1 receptors. Our translational human genomic studies have identified three G protein subunit alpha I2 (GNAI2) single nucleotide polymorphisms (SNPs) as potential biomarkers in individuals with salt sensitivity and essential hypertension. Collectively, PVN Gαi2 proteins-gated pathways appear to be highly conserved in salt resistance to counter the effects of acute and chronic challenges to fluid and electrolyte homeostasis on blood pressure via a renal sympathetic nerve-dependent mechanism.
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Affiliation(s)
- Razie Amraei
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, United States
| | - Jesse D. Moreira
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- Department of Medicine, Boston University School of Medicine, Boston, MA, United States
| | - Richard D. Wainford
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
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Inverse Salt Sensitivity of Blood Pressure: Mechanisms and Potential Relevance for Prevention of Cardiovascular Disease. Curr Hypertens Rep 2022; 24:361-374. [PMID: 35708819 DOI: 10.1007/s11906-022-01201-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE OF REVIEW To review the etiology of inverse salt sensitivity of blood pressure (BP). RECENT FINDINGS Both high and low sodium (Na+) intake can be associated with increased BP and cardiovascular morbidity and mortality. However, little is known regarding the mechanisms involved in the increase in BP in response to low Na+ intake, a condition termed inverse salt sensitivity of BP, which affects approximately 15% of the adult population. The renal proximal tubule is important in regulating up to 70% of renal Na+ transport. The renin-angiotensin and renal dopaminergic systems play both synergistic and opposing roles in the regulation of Na+ transport in this nephron segment. Clinical studies have demonstrated that individuals express a "personal salt index" (PSI) that marks whether they are salt-resistant, salt-sensitive, or inverse salt-sensitive. Inverse salt sensitivity results in part from genetic polymorphisms in various Na+ regulatory genes leading to a decrease in natriuretic activity and an increase in renal tubular Na+ reabsorption leading to an increase in BP. This article reviews the potential mechanisms of a new pathophysiologic entity, inverse salt sensitivity of BP, which affects approximately 15% of the general adult population.
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Frame AA, Nist KM, Kim K, Kuwabara JT, Wainford RD. Natriuresis During an Acute Intravenous Sodium Chloride Infusion in Conscious Sprague Dawley Rats Is Mediated by a Blood Pressure-Independent α1-Adrenoceptor-Mediated Mechanism. Front Physiol 2022; 12:784957. [PMID: 35111076 PMCID: PMC8802910 DOI: 10.3389/fphys.2021.784957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
The mechanisms that sense alterations in total body sodium content to facilitate sodium homeostasis in response to an acute sodium challenge that does not increase blood pressure have not been fully elucidated. We hypothesized that the renal sympathetic nerves are critical to mediate natriuresis via α1- or β-adrenoceptors signal transduction pathways to maintain sodium balance in the face of acute increases in total body sodium content that do not activate the pressure-natriuresis mechanism. To address this hypothesis, we used acute bilateral renal denervation (RDNX), an anteroventral third ventricle (AV3V) lesion and α1- or β-antagonism during an acute 1M NaCl sodium challenge in conscious male Sprague Dawley rats. An acute 1M NaCl infusion did not alter blood pressure and evoked profound natriuresis and sympathoinhibition. Acute bilateral RDNX attenuated the natriuretic and sympathoinhibitory responses evoked by a 1M NaCl infusion [peak natriuresis (μeq/min) sham 14.5 ± 1.3 vs. acute RDNX: 9.2 ± 1.4, p < 0.05; plasma NE (nmol/L) sham control: 44 ± 4 vs. sham 1M NaCl infusion 11 ± 2, p < 0.05; acute RDNX control: 42 ± 6 vs. acute RDNX 1M NaCl infusion 25 ± 3, p < 0.05]. In contrast, an AV3V lesion did not impact the cardiovascular, renal excretory or sympathoinhibitory responses to an acute 1M NaCl infusion. Acute i.v. α1-adrenoceptor antagonism with terazosin evoked a significant drop in baseline blood pressure and significantly attenuated the natriuretic response to a 1M NaCl load [peak natriuresis (μeq/min) saline 17.2 ± 1.4 vs. i.v. terazosin 7.8 ± 2.5, p < 0.05]. In contrast, acute β-adrenoceptor antagonism with i.v. propranolol infusion did not impact the cardiovascular or renal excretory responses to an acute 1M NaCl infusion. Critically, the natriuretic response to an acute 1M NaCl infusion was significantly blunted in rats receiving a s.c. infusion of the α1-adrenoceptor antagonist terazosin at a dose that did not lower baseline blood pressure [peak natriuresis (μeq/min) sc saline: 18 ± 1 vs. sc terazosin 7 ± 2, p < 0.05]. Additionally, a s.c. infusion of the α1-adrenoceptor antagonist terazosin further attenuated the natriuretic response to a 1M NaCl infusion in acutely RDNX animals. Collectively these data indicate a specific role of a blood pressure-independent renal sympathetic nerve-dependent α1-adrenoceptor-mediated pathway in the natriuretic and sympathoinhibitory responses evoked by acute increases in total body sodium.
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Affiliation(s)
- Alissa A. Frame
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Kayla M. Nist
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Kiyoung Kim
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Jill T. Kuwabara
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Richard D. Wainford
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- *Correspondence: Richard D. Wainford,
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Moreira JD, Nist KM, Carmichael CY, Kuwabara JT, Wainford RD. Sensory Afferent Renal Nerve Activated Gαi 2 Subunit Proteins Mediate the Natriuretic, Sympathoinhibitory and Normotensive Responses to Peripheral Sodium Challenges. Front Physiol 2021; 12:771167. [PMID: 34916958 PMCID: PMC8669768 DOI: 10.3389/fphys.2021.771167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/09/2021] [Indexed: 11/15/2022] Open
Abstract
We have previously reported that brain Gαi2 subunit proteins are required to maintain sodium homeostasis and are endogenously upregulated in the hypothalamic paraventricular nucleus (PVN) in response to increased dietary salt intake to maintain a salt resistant phenotype in rats. However, the origin of the signal that drives the endogenous activation and up-regulation of PVN Gαi2 subunit protein signal transduction pathways is unknown. By central oligodeoxynucleotide (ODN) administration we show that the pressor responses to central acute administration and central infusion of sodium chloride occur independently of brain Gαi2 protein pathways. In response to an acute volume expansion, we demonstrate, via the use of selective afferent renal denervation (ADNX) and anteroventral third ventricle (AV3V) lesions, that the sensory afferent renal nerves, but not the sodium sensitive AV3V region, are mechanistically involved in Gαi2 protein mediated natriuresis to an acute volume expansion [peak natriuresis (μeq/min) sham AV3V: 43 ± 4 vs. AV3V 45 ± 4 vs. AV3V + Gαi2 ODN 25 ± 4, p < 0.05; sham ADNX: 43 ± 4 vs. ADNX 23 ± 6, AV3V + Gαi2 ODN 25 ± 3, p < 0.05]. Furthermore, in response to chronically elevated dietary sodium intake, endogenous up-regulation of PVN specific Gαi2 proteins does not involve the AV3V region and is mediated by the sensory afferent renal nerves to counter the development of the salt sensitivity of blood pressure (MAP [mmHg] 4% NaCl; Sham ADNX 124 ± 4 vs. ADNX 145 ± 4, p < 0.05; Sham AV3V 125 ± 4 vs. AV3V 121 ± 5). Additionally, the development of the salt sensitivity of blood pressure following central ODN-mediated Gαi2 protein down-regulation occurs independently of the actions of the brain angiotensin II type 1 receptor. Collectively, our data suggest that in response to alterations in whole body sodium the peripheral sensory afferent renal nerves, but not the central AV3V sodium sensitive region, evoke the up-regulation and activation of PVN Gαi2 protein gated pathways to maintain a salt resistant phenotype. As such, both the sensory afferent renal nerves and PVN Gαi2 protein gated pathways, represent potential targets for the treatment of the salt sensitivity of blood pressure.
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Affiliation(s)
- Jesse D. Moreira
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Medicine, School of Medicine, Boston University, Boston, MA, United States
| | - Kayla M. Nist
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Anatomy & Neurobiology, School of Medicine, Boston University, Boston, MA, United States
| | - Casey Y. Carmichael
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
| | - Jill T. Kuwabara
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
| | - Richard D. Wainford
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
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Tseng CC, Wong MC, Liao WT, Chen CJ, Lee SC, Yen JH, Chang SJ. Genetic Variants in Transcription Factor Binding Sites in Humans: Triggered by Natural Selection and Triggers of Diseases. Int J Mol Sci 2021; 22:ijms22084187. [PMID: 33919522 PMCID: PMC8073710 DOI: 10.3390/ijms22084187] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/14/2022] Open
Abstract
Variants of transcription factor binding sites (TFBSs) constitute an important part of the human genome. Current evidence demonstrates close links between nucleotides within TFBSs and gene expression. There are multiple pathways through which genomic sequences located in TFBSs regulate gene expression, and recent genome-wide association studies have shown the biological significance of TFBS variation in human phenotypes. However, numerous challenges remain in the study of TFBS polymorphisms. This article aims to cover the current state of understanding as regards the genomic features of TFBSs and TFBS variants; the mechanisms through which TFBS variants regulate gene expression; the approaches to studying the effects of nucleotide changes that create or disrupt TFBSs; the challenges faced in studies of TFBS sequence variations; the effects of natural selection on collections of TFBSs; in addition to the insights gained from the study of TFBS alleles related to gout, its associated comorbidities (increased body mass index, chronic kidney disease, diabetes, dyslipidemia, coronary artery disease, ischemic heart disease, hypertension, hyperuricemia, osteoporosis, and prostate cancer), and the treatment responses of patients.
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Affiliation(s)
- Chia-Chun Tseng
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (C.-C.T.); (J.-H.Y.)
- Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80756, Taiwan
| | - Man-Chun Wong
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Wei-Ting Liao
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80756, Taiwan
- Correspondence: (W.-T.L.); (S.-J.C.); Tel.: +886-7-3121101 (W.-T.L.); +886-7-5916679 (S.-J.C.); Fax:+886-7-3125339 (W.-T.L.); +886-7-5919264 (S.-J.C.)
| | - Chung-Jen Chen
- Department of Internal Medicine, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung 80145, Taiwan;
| | - Su-Chen Lee
- Laboratory Diagnosis of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Jeng-Hsien Yen
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (C.-C.T.); (J.-H.Y.)
- Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80756, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan
- Department of Biological Science and Technology, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Shun-Jen Chang
- Department of Kinesiology, Health and Leisure Studies, National University of Kaohsiung, Kaohsiung 81148, Taiwan
- Correspondence: (W.-T.L.); (S.-J.C.); Tel.: +886-7-3121101 (W.-T.L.); +886-7-5916679 (S.-J.C.); Fax:+886-7-3125339 (W.-T.L.); +886-7-5919264 (S.-J.C.)
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12
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Gao H, Bigalke J, Jiang E, Fan Y, Chen B, Chen QH, Shan Z. TNFα Triggers an Augmented Inflammatory Response in Brain Neurons from Dahl Salt-Sensitive Rats Compared with Normal Sprague Dawley Rats. Cell Mol Neurobiol 2021; 42:1787-1800. [PMID: 33625627 PMCID: PMC8382783 DOI: 10.1007/s10571-021-01056-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 02/04/2021] [Indexed: 12/23/2022]
Abstract
Tumor Necrosis Factor (TNF)-α is a proinflammatory cytokine (PIC) and has been implicated in a variety of illness including cardiovascular disease. The current study investigated the inflammatory response trigged by TNFα in both cultured brain neurons and the hypothalamic paraventricular nucleus (PVN), a key cardiovascular relevant brain area, of the Sprague Dawley (SD) rats. Our results demonstrated that TNFα treatment induces a dose- and time-dependent increase in mRNA expression of PICs including Interleukin (IL)-1β and Interleukin-6 (IL6); chemokines including C-C Motif Chemokine Ligand 5 (CCL5) and C-C Motif Chemokine Ligand 12 (CCL12), inducible nitric oxide synthase (iNOS), as well as transcription factor NF-kB in cultured brain neurons from neonatal SD rats. Consistent with this finding, immunostaining shows that TNFα treatment increases immunoreactivity of IL1β, CCL5, iNOS and stimulates activation or expression of NF-kB, in both cultured brain neurons and the PVN of adult SD rats. We further compared mRNA expression of the aforementioned genes in basal level as well as in response to TNFα challenge between SD rats and Dahl Salt-sensitive (Dahl-S) rats, an animal model of salt-sensitive hypertension. Dahl-S brain neurons presented higher baseline levels as well as greater response to TNFα challenge in mRNA expression of CCL5, iNOS and IL1β. Furthermore, central administration of TNFα caused significant higher response in CCL12 in the PVN of Dahl-S rats. The increased inflammatory response to TNFα in Dahl-S rats may be indicative of an underlying mechanism for enhanced pressor reactivity to salt intake in the Dahl-S rat model.
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Affiliation(s)
- Huanjia Gao
- Department of Kinesiology & Integrative Physiology, Michigan Technological University, Houghton, MI, 49931, USA.,The Second Clinical College of Guangzhou, University of Chinese Medicine, Guangzhou, China
| | - Jeremy Bigalke
- Department of Kinesiology & Integrative Physiology, Michigan Technological University, Houghton, MI, 49931, USA
| | - Enshe Jiang
- Department of Kinesiology & Integrative Physiology, Michigan Technological University, Houghton, MI, 49931, USA.,Institute of Nursing and Health, Henan University, Henan, China.,Henan International Joint Laboratory of Nuclear Protein Regulation, Henan University, Henan, China
| | - Yuanyuan Fan
- Department of Kinesiology & Integrative Physiology, Michigan Technological University, Houghton, MI, 49931, USA.,School of Life Sciences, Henan University, Henan, China
| | - Bojun Chen
- Department of Emergency, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Qing-Hui Chen
- Department of Kinesiology & Integrative Physiology, Michigan Technological University, Houghton, MI, 49931, USA.,Health Research Institute, Michigan Technological University, Houghton, MI, 49931, USA
| | - Zhiying Shan
- Department of Kinesiology & Integrative Physiology, Michigan Technological University, Houghton, MI, 49931, USA. .,Health Research Institute, Michigan Technological University, Houghton, MI, 49931, USA.
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13
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Chaudhary P, Wainford RD. Neuroanatomical characterization of Gαi 2-expressing neurons in the hypothalamic paraventricular nucleus of male and female Sprague-Dawley rats. Physiol Genomics 2021; 53:12-21. [PMID: 33252993 PMCID: PMC7847047 DOI: 10.1152/physiolgenomics.00097.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/26/2020] [Accepted: 11/30/2020] [Indexed: 11/22/2022] Open
Abstract
Hypertension is a global health burden. The hypothalamic paraventricular nucleus (PVN) is an essential component of the neuronal network that regulates sodium homeostasis and blood pressure (BP). Previously, we have shown PVN-specific G protein-coupled receptor-coupled Gαi2 subunit proteins are essential to counter the development of salt-sensitive hypertension by mediating the sympathoinhibitory and natriuretic responses to increased dietary sodium intake to maintain sodium homeostasis and normotension. However, the cellular localization and identity of PVN Gαi2-expressing neurons are currently unknown. In this study using in situ hybridization, we determined the neuroanatomical characterization of Gαi2-expressing PVN neurons in 3-mo-old male and female Sprague-Dawley rats. We observed that Gαi2-expressing neurons containing Gnai2 mRNA are highly localized in the parvocellular region of the hypothalamic PVN. At level 2 of the hypothalamic PVN, Gnai2 mRNA colocalized with ∼ 85% of GABA-expressing neurons and ∼28% of glutamatergic neurons. Additionally, within level 2 Gnai2 mRNA colocalized with ∼75% of corticotrophin-releasing hormone PVN neurons. Gnai2 neurons had lower colocalization with tyrosine hydroxylase (∼33%)-, oxytocin (∼6%)-, and arginine vasopressin (∼10%)-expressing parvocellular neurons in level 2 PVN. Colocalization was similar among male and female rats. The high colocalization of Gnai2 mRNA with GABAergic neurons, in conjunction with our previous findings that PVN Gαi2 proteins mediate sympathoinhibition, suggests that Gαi2 proteins potentially modulate GABAergic signaling to impact sympathetic outflow and BP.
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Affiliation(s)
- Parul Chaudhary
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts
- The Whitaker Cardiovascular Institute, Boston University, Boston, Massachusetts
| | - Richard D Wainford
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts
- The Whitaker Cardiovascular Institute, Boston University, Boston, Massachusetts
- Department of Health Sciences, Boston University Sargent College, Boston, Massachusetts
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14
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Salt sensitivity and hypertension. J Hum Hypertens 2020; 35:184-192. [PMID: 32862203 DOI: 10.1038/s41371-020-00407-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 07/15/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022]
Abstract
Salt sensitivity refers to the physiological trait present in mammals, including humans, by which the blood pressure (BP) of some members of the population exhibits changes parallel to changes in salt intake. It is commoner in elderly, females, Afro-Americans, patients with chronic kidney disease (CKD) and insulin resistance. Increased salt intake promotes an expansion of extracellular fluid volume and increases cardiac output. Salt-sensitive individuals present an abnormal kidney reaction to salt intake; the kidneys retain most of the salt due to an abnormal over-reactivity of sympathetic nervous system and a blunted suppression of renin-angiotensin axis. Moreover, instead of peripheral vascular resistance falling, salt-sensitive subjects present increased vascular resistance due mainly to impaired nitric oxide synthesis in endothelium. Recent studies have shown that part of the dietary salt loading accumulates in skin. Hypertensive and patients with CKD seem to have more sodium in skin comparing to healthy ones. However, we still have not fully explained the link between skin sodium, BP and salt sensitivity. Finally, although salt sensitivity plays a meaningful role in BP pathophysiology, it cannot be used by the physician in everyday patient's care, mainly due to lack of a simple and practical diagnostic test.
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15
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Carmichael CY, Kuwabara JT, Pascale CL, Moreira JD, Mahne SE, Kapusta DR, Rosene DL, Williams JS, Cunningham JT, Wainford RD. Hypothalamic Paraventricular Nucleus Gαi 2 (Guanine Nucleotide-Binding Protein Alpha Inhibiting Activity Polypeptide 2) Protein-Mediated Neural Control of the Kidney and the Salt Sensitivity of Blood Pressure. Hypertension 2020; 75:1002-1011. [PMID: 32148128 PMCID: PMC7329357 DOI: 10.1161/hypertensionaha.119.13777] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We have previously reported that in salt-resistant rat phenotypes brain, Gαi2 (guanine nucleotide-binding protein alpha inhibiting activity polypeptide 2) proteins are required to maintain blood pressure and sodium balance. However, the impact of hypothalamic paraventricular nucleus (PVN) Gαi2 proteins on the salt sensitivity of blood pressure is unknown. Here, by the bilateral PVN administration of a targeted Gαi2 oligodeoxynucleotide, we show that PVN-specific Gαi2 proteins are required to facilitate the full natriuretic response to an acute volume expansion (peak natriuresis [μeq/min] scrambled (SCR) oligodeoxynucleotide 41±3 versus Gαi2 oligodeoxynucleotide 18±4; P<0.05) via a renal nerve-dependent mechanism. Furthermore, in response to chronically elevated dietary sodium intake, PVN-specific Gαi2 proteins are essential to counter renal nerve-dependent salt-sensitive hypertension (mean arterial pressure [mm Hg] 8% NaCl; SCR oligodeoxynucleotide 128±2 versus Gαi2 oligodeoxynucleotide 147±3; P<0.05). This protective pathway involves activation of PVN Gαi2 signaling pathways, which mediate sympathoinhibition to the blood vessels and kidneys (renal norepinephrine [pg/mg] 8% NaCl; SCR oligodeoxynucleotide 375±39 versus Gαi2 oligodeoxynucleotide 850±27; P<0.05) and suppression of the activity of the sodium chloride cotransporter assessed as peak natriuresis to hydrochlorothiazide. Additionally, central oligodeoxynucleotide-mediated Gαi2 protein downregulation prevented PVN parvocellular neuron activation, assessed by FosB immunohistochemistry, in response to increased dietary salt intake. In our analysis of the UK BioBank data set, it was observed that 2 GNAI2 single nucleotide polymorphism (SNP) (rs2298952, P=0.041; rs4547694, P=0.017) significantly correlate with essential hypertension. Collectively, our data suggest that selective targeting and activation of PVN Gαi2 proteins is a novel therapeutic approach for the treatment of salt-sensitive hypertension.
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Affiliation(s)
- Casey Y Carmichael
- The Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Jill T Kuwabara
- The Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Crissey L Pascale
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Jesse D Moreira
- The Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
- Department of Health Sciences, Boston University Sargent College, Boston, Massachusetts
| | - Sarah E Mahne
- The Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Daniel R Kapusta
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Douglas L Rosene
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts
| | - Jonathan S Williams
- Division of Endocrinology, Diabetes, Hypertension, Brigham and Women’s, Harvard Medical School, Boston, Massachusetts
| | - J. Thomas Cunningham
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Richard D Wainford
- The Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
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16
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Moreira JD, Chaudhary P, Frame AA, Puleo F, Nist KM, Abkin EA, Moore TL, George JC, Wainford RD. Inhibition of microglial activation in rats attenuates paraventricular nucleus inflammation in Gαi 2 protein-dependent, salt-sensitive hypertension. Exp Physiol 2019; 104:1892-1910. [PMID: 31631436 PMCID: PMC6884700 DOI: 10.1113/ep087924] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/09/2019] [Indexed: 12/14/2022]
Abstract
NEW FINDINGS • What is the central question of this study? We hypothesized that central inflammatory processes that involve activation of microglia and astrocytes contribute to the development of Gαi2 protein-dependent, salt-sensitive hypertension. • What is the main finding and its importance? The main finding is that PVN-specific inflammatory processes, driven by microglial activation, appear to be linked to the development of Gαi2 protein-dependent, salt-sensitive hypertension in Sprague-Dawley rats. This finding might reveal new mechanistic targets in the treatment of hypertension. ABSTRACT The central mechanisms underlying salt-sensitive hypertension, a significant public health issue, remain to be established. Researchers in our laboratory have reported that hypothalamic paraventricular nucleus (PVN) Gαi2 proteins mediate the sympathoinhibitory and normotensive responses to high sodium intake in salt-resistant rats. Given the recent evidence of central inflammation in animal models of hypertension, we hypothesized that PVN inflammation contributes to Gαi2 protein-dependent, salt-sensitive hypertension. Male Sprague-Dawley rats received chronic intracerebroventricular infusions of a targeted Gαi2 or control scrambled oligodeoxynucleotide (ODN) and were maintained for 7 days on a normal-salt (NS; 0.6% NaCl) or high-salt (HS; 4% NaCl) diet; in subgroups on HS, intracerebroventricular minocycline (microglial inhibitor) was co-infused with ODNs. Radiotelemetry was used in subgroups of rats to measure mean arterial pressure (MAP) chronically. In a separate group of rats, plasma noradrenaline, plasma renin activity, urinary angiotensinogen and mRNA levels of the PVN pro-inflammatory cytokines TNFα, IL-1β and IL-6 and the anti-inflammatory cytokine IL-10 were assessed. In additional groups, immunohistochemistry was performed for markers of PVN and subfornical organ microglial activation and cytokine levels and PVN astrocyte activation. High salt intake evoked salt-sensitive hypertension, increased plasma noradrenaline, PVN pro-inflammatory cytokine mRNA upregulation, anti-inflammatory cytokine mRNA downregulation and PVN-specific microglial activation in rats receiving a targeted Gαi2 but not scrambled ODN. Minocycline co-infusion significantly attenuated the increase in MAP and abolished the increase in plasma noradrenaline and inflammation in Gαi2 ODN-infused animals on HS. Our data suggest that central Gαi2 protein prevents microglial-mediated PVN inflammation and the development of salt-sensitive hypertension.
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Affiliation(s)
- Jesse D. Moreira
- The Whitaker Cardiovascular InstituteBoston UniversityBostonMAUSA
- Department of Health SciencesBoston University Sargent CollegeBostonMAUSA
| | - Parul Chaudhary
- The Whitaker Cardiovascular InstituteBoston UniversityBostonMAUSA
- Department of Pharmacology and Experimental TherapeuticsBoston University School of MedicineBostonMAUSA
| | - Alissa A. Frame
- The Whitaker Cardiovascular InstituteBoston UniversityBostonMAUSA
- Department of Pharmacology and Experimental TherapeuticsBoston University School of MedicineBostonMAUSA
| | - Franco Puleo
- The Whitaker Cardiovascular InstituteBoston UniversityBostonMAUSA
- Department of Pharmacology and Experimental TherapeuticsBoston University School of MedicineBostonMAUSA
| | - Kayla M. Nist
- The Whitaker Cardiovascular InstituteBoston UniversityBostonMAUSA
- Department of Anatomy & NeurobiologyBoston University School of MedicineBostonMAUSA
| | - Eric A. Abkin
- The Whitaker Cardiovascular InstituteBoston UniversityBostonMAUSA
- Department of Health SciencesBoston University Sargent CollegeBostonMAUSA
| | - Tara L. Moore
- Department of Anatomy & NeurobiologyBoston University School of MedicineBostonMAUSA
| | - Jonique C. George
- Department of Pharmacology and Experimental TherapeuticsBoston University School of MedicineBostonMAUSA
| | - Richard D. Wainford
- The Whitaker Cardiovascular InstituteBoston UniversityBostonMAUSA
- Department of Health SciencesBoston University Sargent CollegeBostonMAUSA
- Department of Pharmacology and Experimental TherapeuticsBoston University School of MedicineBostonMAUSA
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17
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Frame AA, Puleo F, Kim K, Walsh KR, Faudoa E, Hoover RS, Wainford RD. Sympathetic regulation of NCC in norepinephrine-evoked salt-sensitive hypertension in Sprague-Dawley rats. Am J Physiol Renal Physiol 2019; 317:F1623-F1636. [PMID: 31608673 DOI: 10.1152/ajprenal.00264.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Salt sensitivity of blood pressure is characterized by inappropriate sympathoexcitation and renal Na+ reabsorption during high salt intake. In salt-resistant animal models, exogenous norepinephrine (NE) infusion promotes salt-sensitive hypertension and prevents dietary Na+-evoked suppression of the Na+-Cl- cotransporter (NCC). Studies of the adrenergic signaling pathways that modulate NCC activity during NE infusion have yielded conflicting results implicating α1- and/or β-adrenoceptors and a downstream kinase network that phosphorylates and activates NCC, including with no lysine kinases (WNKs), STE20/SPS1-related proline-alanine-rich kinase (SPAK), and oxidative stress response 1 (OxSR1). In the present study, we used selective adrenoceptor antagonism in NE-infused male Sprague-Dawley rats to investigate the differential roles of α1- and β-adrenoceptors in sympathetically mediated NCC regulation. NE infusion evoked salt-sensitive hypertension and prevented dietary Na+-evoked suppression of NCC mRNA, protein expression, phosphorylation, and in vivo activity. Impaired NCC suppression during high salt intake in NE-infused rats was paralleled by impaired suppression of WNK1 and OxSR1 expression and SPAK/OxSR1 phosphorylation and a failure to increase WNK4 expression. Antagonism of α1-adrenoceptors before high salt intake or after the establishment of salt-sensitive hypertension restored dietary Na+-evoked suppression of NCC, resulted in downregulation of WNK4, SPAK, and OxSR1, and abolished the salt-sensitive component of hypertension. In contrast, β-adrenoceptor antagonism attenuated NE-evoked hypertension independently of dietary Na+ intake and did not restore high salt-evoked suppression of NCC. These findings suggest that a selective, reversible, α1-adenoceptor-gated WNK/SPAK/OxSR1 NE-activated signaling pathway prevents dietary Na+-evoked NCC suppression, promoting the development and maintenance of salt-sensitive hypertension.
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Affiliation(s)
- Alissa A Frame
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Franco Puleo
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Kiyoung Kim
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Kathryn R Walsh
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Elizabeth Faudoa
- College of Arts and Sciences, Boston University, Boston, Massachusetts
| | - Robert S Hoover
- Research Service, Atlanta Veterans Affairs Medical Center, Decatur, Georgia.,Division of Nephrology, Department of Medicine, Emory University, Atlanta, Georgia
| | - Richard D Wainford
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
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18
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Frame AA, Carmichael CY, Kuwabara JT, Cunningham JT, Wainford RD. Role of the afferent renal nerves in sodium homeostasis and blood pressure regulation in rats. Exp Physiol 2019; 104:1306-1323. [PMID: 31074108 PMCID: PMC6675646 DOI: 10.1113/ep087700] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022]
Abstract
New Findings What is the central question of this study? What are the differential roles of the mechanosensitive and chemosensitive afferent renal nerves in the reno‐renal reflex that promotes natriuresis, sympathoinhibition and normotension during acute and chronic challenges to sodium homeostasis? What is the main finding and its importance? The mechanosensitive afferent renal nerves contribute to an acute natriuretic sympathoinhibitory reno‐renal reflex that may be integrated within the paraventricular nucleus of the hypothalamus. Critically, the afferent renal nerves are required for the maintenance of salt resistance in Sprague–Dawley and Dahl salt‐resistant rats and attenuate the development of Dahl salt‐sensitive hypertension.
Abstract These studies tested the hypothesis that in normotensive salt‐resistant rat phenotypes the mechanosensitive afferent renal nerve (ARN) reno‐renal reflex promotes natriuresis, sympathoinhibition and normotension during acute and chronic challenges to fluid and electrolyte homeostasis. Selective ARN ablation was conducted prior to (1) an acute isotonic volume expansion (VE) or 1 m NaCl infusion in Sprague–Dawley (SD) rats and (2) chronic high salt intake in SD, Dahl salt‐resistant (DSR), and Dahl salt‐sensitive (DSS) rats. ARN responsiveness following high salt intake was assessed ex vivo in response to noradrenaline and sodium concentration (SD, DSR and DSS) and via in vivo manipulation of renal pelvic pressure and sodium concentration (SD and DSS). ARN ablation attenuated the natriuretic and sympathoinhibitory responses to an acute VE [peak natriuresis (µeq min−1) sham 52 ± 5 vs. ARN ablation 28 ± 3, P < 0.05], but not a hypertonic saline infusion in SD rats. High salt (HS) intake enhanced ARN reno‐renal reflex‐mediated natriuresis in response to direct increases in renal pelvic pressure (mechanoreceptor stimulus) in vivo and ARN responsiveness to noradrenaline ex vivo in SD, but not DSS, rats. In vivo and ex vivo ARN responsiveness to increased renal pelvic sodium concentration (chemoreceptor stimulus) was unaltered during HS intake. ARN ablation evoked sympathetically mediated salt‐sensitive hypertension in SD rats [MAP (mmHg): sham normal salt 102 ± 2 vs. sham HS 104 ± 2 vs. ARN ablation normal salt 103 ± 2 vs. ARN ablation HS 121 ± 2, P < 0.05] and DSR rats and exacerbated DSS hypertension. The mechanosensitive ARNs mediate an acute sympathoinhibitory natriuretic reflex and counter the development of salt‐sensitive hypertension.
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Affiliation(s)
- Alissa A Frame
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Casey Y Carmichael
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Jill T Kuwabara
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - J Thomas Cunningham
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Richard D Wainford
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
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19
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Sodium sensitivity of blood pressure in Chinese populations. J Hum Hypertens 2019; 34:94-107. [PMID: 30631129 DOI: 10.1038/s41371-018-0152-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/15/2018] [Accepted: 12/06/2018] [Indexed: 12/12/2022]
Abstract
Hypertension is an enormous public-health challenge in the world due to its high prevalence and consequent increased cardiovascular disease morbidity and mortality. Observational epidemiologic studies and clinical trials have demonstrated a causal relationship between sodium intake and elevated blood pressure (BP). However, BP changes in response to sodium intervention vary among individuals-a trait called sodium sensitivity. This paper aims to review the recent advances in sodium-sensitivity research in Chinese and other populations. Older age, female gender, and black race are associated with high sodium sensitivity. Both genetic and environmental factors influence BP sodium sensitivity. Physical activity and dietary potassium intake are associated with reduced sodium sensitivity while obesity, metabolic syndrome, and elevated BP are associated with increased sodium sensitivity. Familial studies have documented a moderate heritability of sodium sensitivity. Candidate gene association studies, genome-wide association studies, whole-exome, and whole-genome sequencing studies have been conducted to elucidate the genomic mechanisms of sodium sensitivity. The Genetic Epidemiology Network of Salt Sensitivity (GenSalt) study, the largest family-based feeding study to date, was conducted among 1906 Han Chinese in rural northern China. This study showed that ~32.4% of Chinese adults were sodium sensitive. Additionally, several genetic variants were found to be associated with sodium sensitivity. Findings from the GenSalt Study and others indicate that sodium sensitivity is a reproducible trait and both lifestyle factors and genetic variants play a role in this complex trait. Discovering biomarkers and underlying mechanisms for sodium sensitivity will help to develop individualized intervention strategies for hypertension.
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20
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Zhang X, Frame AA, Williams JS, Wainford RD. GNAI2 polymorphic variance associates with salt sensitivity of blood pressure in the Genetic Epidemiology Network of Salt Sensitivity study. Physiol Genomics 2018; 50:724-725. [PMID: 29906209 PMCID: PMC6172609 DOI: 10.1152/physiolgenomics.00141.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Salt sensitivity of blood pressure (BP) increases hypertension risk and associated adverse cardiovascular outcomes. At present, there are no validated rapid tests or diagnostic markers to identify salt sensitivity of BP in clinical practice. Based on our prior animal studies that report a role for brain Gαi2 proteins in the salt sensitivity of BP and evidence that GNAI2 single nucleotide polymorphisms (SNPs) associate with hypertension risk, we investigated the hypothesis that GNAI2 SNPs associate with salt sensitivity of BP in humans. Our data provide the first evidence that a GNAI2 SNP ( rs10510755 ) positively associates with salt sensitivity of BP in the Genetic Epidemiology of Salt Sensitivity data set (continuous phenotype P = 0.049, case-control phenotype P = 0.039; n = 968), independently of subject sex or age. These observations suggest that genotyping at GNAI2 may be a useful biomarker in identifying individuals at risk for developing salt-sensitive BP and related complications or in identifying salt sensitivity within the hypertensive population.
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Affiliation(s)
- Xiaoling Zhang
- Section of Biomedical Genetics, Boston University School of Medicine and The Department of Biostatistics, Boston University School of Public Health , Boston, Massachusetts
| | - Alissa A Frame
- Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Jonathan S Williams
- Division of Endocrinology, Diabetes, Hypertension, Brigham and Women's, Harvard Medical School , Boston, Massachusetts
| | - Richard D Wainford
- Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
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Frame AA, Wainford RD. Mechanisms of altered renal sodium handling in age-related hypertension. Am J Physiol Renal Physiol 2018; 315:F1-F6. [PMID: 29442548 DOI: 10.1152/ajprenal.00594.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The prevalence of hypertension rises with age to approximately two out of three adults over the age of 60 in the United States. Although the mechanisms underlying age-related hypertension are incompletely understood, sodium homeostasis is critical to the long-term regulation of blood pressure and there is strong evidence that aging is associated with alterations in renal sodium handling. This minireview focuses on recent advancements in our understanding of the vascular, neurohumoral, and renal mechanisms that influence sodium homeostasis and promote age-related hypertension.
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Affiliation(s)
- Alissa A Frame
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine and The Whitaker Cardiovascular Institute , Boston, Massachusetts
| | - Richard D Wainford
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine and The Whitaker Cardiovascular Institute , Boston, Massachusetts
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22
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Jaimes R, Swiercz A, Sherman M, Muselimyan N, Marvar PJ, Posnack NG. Plastics and cardiovascular health: phthalates may disrupt heart rate variability and cardiovascular reactivity. Am J Physiol Heart Circ Physiol 2017; 313:H1044-H1053. [PMID: 28842438 PMCID: PMC5792203 DOI: 10.1152/ajpheart.00364.2017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/17/2017] [Accepted: 08/17/2017] [Indexed: 12/11/2022]
Abstract
Plastics have revolutionized medical device technology, transformed hematological care, and facilitated modern cardiology procedures. Despite these advances, studies have shown that phthalate chemicals migrate out of plastic products and that these chemicals are bioactive. Recent epidemiological and research studies have suggested that phthalate exposure adversely affects cardiovascular function. Our objective was to assess the safety and biocompatibility of phthalate chemicals and resolve the impact on cardiovascular and autonomic physiology. Adult mice were implanted with radiofrequency transmitters to monitor heart rate variability, blood pressure, and autonomic regulation in response to di-2-ethylhexyl-phthalate (DEHP) exposure. DEHP-treated animals displayed a decrease in heart rate variability (-17% SD of normal beat-to-beat intervals and -36% high-frequency power) and an exaggerated mean arterial pressure response to ganglionic blockade (31.5% via chlorisondamine). In response to a conditioned stressor, DEHP-treated animals displayed enhanced cardiovascular reactivity (-56% SD major axis Poincarè plot) and prolonged blood pressure recovery. Alterations in cardiac gene expression of endothelin-1, angiotensin-converting enzyme, and nitric oxide synthase may partly explain these cardiovascular alterations. This is the first study to show an association between phthalate chemicals that are used in medical devices with alterations in autonomic regulation, heart rate variability, and cardiovascular reactivity. Because changes in autonomic balance often precede clinical manifestations of hypertension, atherosclerosis, and conduction abnormalities, future studies are warranted to assess the downstream impact of plastic chemical exposure on end-organ function in sensitive patient populations. This study also highlights the importance of adopting safer biomaterials, chemicals, and/or surface coatings for use in medical devices.NEW & NOTEWORTHY Phthalates are widely used in the manufacturing of consumer and medical products. In the present study, di-2-ethylhexyl-phthalate exposure was associated with alterations in heart rate variability and cardiovascular reactivity. This highlights the importance of investigating the impact of phthalates on health and identifying suitable alternatives for medical device manufacturing.
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Affiliation(s)
- Rafael Jaimes
- 1Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Health System, Washington, District of Columbia; ,2Children’s National Heart Institute, Children’s National Health System, Washington, District of Columbia; and
| | - Adam Swiercz
- 3Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
| | - Meredith Sherman
- 1Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Health System, Washington, District of Columbia;
| | - Narine Muselimyan
- 3Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
| | - Paul J. Marvar
- 3Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Health System, Washington, District of Columbia; .,Children's National Heart Institute, Children's National Health System, Washington, District of Columbia; and.,Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
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Ang R, Abramowitz J, Birnbaumer L, Gourine AV, Tinker A. The role of GαO-mediated signaling in the rostral ventrolateral medulla oblongata in cardiovascular reflexes and control of cardiac ventricular excitability. Physiol Rep 2017; 4:4/15/e12860. [PMID: 27528004 PMCID: PMC4985541 DOI: 10.14814/phy2.12860] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 06/20/2016] [Indexed: 12/02/2022] Open
Abstract
The heart is controlled by the sympathetic and parasympathetic limbs of the autonomic nervous system with inhibitory signaling mechanisms recruited in both limbs. The aim of this study was to determine the role of inhibitory heterotrimeric G proteins in the central nervous mechanisms underlying autonomic control of the heart and its potential role in arrhythmogenesis. Mice with conditional deletion of the inhibitory heterotrimeric G protein GαO in the presympathetic area of the rostral ventral lateral medulla (RVLM) were generated to determine the role of GαO‐mediated signalling in autonomic control and electrophysiological properties of the heart. GαO deletion within the RVLM was not associated with changes in heart rate (HR) or the arterial blood pressure at rest (home cage, normal behavior). However, exposure to stressful conditions (novel environment, hypoxia, or hypercapnia) in these mice was associated with abnormal HR responses and an increased baroreflex gain when assessed under urethane anesthesia. This was associated with shortening of the ventricular effective refractory period. This phenotype was reversed by systemic beta‐adrenoceptor blockade, suggesting that GαO depletion in the RVLM increases central sympathetic drive. The data obtained support the hypothesis that GαO‐mediated signaling within the presympathetic circuits of the RVLM contributes to the autonomic control of the heart. GαO deficiency in the RVLM has a significant impact on cardiovascular responses to stress, cardiovascular reflexes and electrical properties of the heart.
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Affiliation(s)
- Richard Ang
- William Harvey Heart Centre, Barts & The London School of Medicine and Dentistry, London, UK Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Joel Abramowitz
- Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Lutz Birnbaumer
- Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Alexander V Gourine
- William Harvey Heart Centre, Barts & The London School of Medicine and Dentistry, London, UK
| | - Andrew Tinker
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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Ali El-Basyuni Y, Li Y, Anand-Srivastava MB. Knockdown of Inhibitory Guanine Nucleotide Binding Protein Giα-2 by Antisense Oligodeoxynucleotides Attenuates the Development of Hypertension and Tachycardia in Spontaneously Hypertensive Rats. J Am Heart Assoc 2016; 5:e004594. [PMID: 27912212 PMCID: PMC5210347 DOI: 10.1161/jaha.116.004594] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 09/30/2016] [Indexed: 11/16/2022]
Abstract
BACKGROUND We previously showed that the levels of both Giα-2 and Giα-3 proteins were augmented in spontaneously hypertensive rats (SHRs) before the onset of hypertension. In addition, intraperitoneal injection of pertussis toxin, which inactivates both Giα proteins, prevented the development of hypertension in SHRs. The aim of the present study was to determine the specific contributions of Giα-2 and Giα-3 proteins to the development of hypertension. METHODS AND RESULTS Antisense oligodeoxynucleotide of Giα-2 and Giα-3 encapsulated in PEG/DOTAP/DOPE cationic liposomes were administrated intravenously into 3-week-old prehypertensive SHRs and Wistar Kyoto rats, whereas the control Wistar Kyoto rats and SHRs received PBS, empty liposomes, or sense. The knockdown of Giα-2 but not Giα-3 protein attenuated tachycardia and prevented the development of hypertension up to age 6 weeks; thereafter, blood pressure started increasing and reached the same level as that of untreated SHRs at 9 weeks. Furthermore, Giα-2 and Giα-3 antisense oligodeoxynucleotide treatments significantly decreased the enhanced levels of Giα-2 and Giα-3 proteins, respectively, and enhanced levels of superoxide anion and NADPH oxidase activity in heart, aorta, and kidney and hyperproliferation of vascular smooth muscle cells from SHRs aged 6 weeks. In addition, antisense oligodeoxynucleotide treatment with Giα-2 but not Giα-3 restored enhanced inhibition of adenylyl cyclase by oxotremorine to WKY levels. CONCLUSIONS These results suggested that the enhanced expression of Giα-2 but not Giα-3 protein plays an important role in the pathogenesis of hypertension and tachycardia in SHRs.
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MESH Headings
- Adenylyl Cyclase Inhibitors/pharmacology
- Animals
- Aorta/metabolism
- Blood Pressure/physiology
- Cells, Cultured
- Disease Models, Animal
- GTP-Binding Protein alpha Subunit, Gi2/deficiency
- GTP-Binding Protein alpha Subunit, Gi2/physiology
- GTP-Binding Protein alpha Subunits, Gi-Go/deficiency
- GTP-Binding Protein alpha Subunits, Gi-Go/physiology
- Gene Knockdown Techniques
- Heart Rate/physiology
- Hypertension/prevention & control
- Kidney/metabolism
- Liposomes/administration & dosage
- Male
- Muscle, Smooth, Vascular/metabolism
- Myocardium/metabolism
- Oligodeoxyribonucleotides, Antisense/physiology
- Rats, Inbred SHR
- Rats, Inbred WKY
- Signal Transduction/physiology
- Tachycardia/prevention & control
- Transfection/methods
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Affiliation(s)
- Yousra Ali El-Basyuni
- Department of Molecular and Integrative Physiology, Faculty of Medicine, University of Montreal, Quebec, Canada
| | - Yuan Li
- Department of Molecular and Integrative Physiology, Faculty of Medicine, University of Montreal, Quebec, Canada
| | - Madhu B Anand-Srivastava
- Department of Molecular and Integrative Physiology, Faculty of Medicine, University of Montreal, Quebec, Canada
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Elijovich F, Weinberger MH, Anderson CAM, Appel LJ, Bursztyn M, Cook NR, Dart RA, Newton-Cheh CH, Sacks FM, Laffer CL. Salt Sensitivity of Blood Pressure: A Scientific Statement From the American Heart Association. Hypertension 2016; 68:e7-e46. [PMID: 27443572 DOI: 10.1161/hyp.0000000000000047] [Citation(s) in RCA: 326] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Abstract
Sympathetic nerve activity is involved in the pathogenesis of salt-sensitive hypertension. The central nervous system, which regulates sympathetic nerve activity and blood pressure, plays a pivotal role. Central sympathoexcitation is deeply involved in the pathogenesis of salt-sensitive hypertension, although the precise mechanisms have not been fully elucidated because of their complexity. The role of brain oxidative stress in sympathoexcitation has been suggested in some types of hypertensive animal models. We have shown that increased brain oxidative stress may elevate arterial pressure through central sympathoexcitation in salt-sensitive hypertension. Several other factors such as mineralocorticoid receptors, aldosterone, corticosterone, epithelial sodium channels, and angiotensin II also play important roles in central sympathetic activation, some of which can be associated with brain oxidative stress. Furthermore, brain paraventricular nucleus Gαi2-protein-mediated transduction has been recently reported as a candidate for the molecular mechanism countering the development of salt-sensitive hypertension.
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27
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Zicha J. Central Gαi2 proteins, sympathetic nervous system and blood pressure regulation. Acta Physiol (Oxf) 2016; 216:258-9. [PMID: 26609797 DOI: 10.1111/apha.12634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- J. Zicha
- Institute of Physiology; Czech Academy of Sciences; Prague Czech Republic
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28
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Carmichael CY, Carmichael ACT, Kuwabara JT, Cunningham JT, Wainford RD. Impaired sodium-evoked paraventricular nucleus neuronal activation and blood pressure regulation in conscious Sprague-Dawley rats lacking central Gαi2 proteins. Acta Physiol (Oxf) 2016; 216:314-29. [PMID: 26412230 PMCID: PMC4764872 DOI: 10.1111/apha.12610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 08/08/2015] [Accepted: 09/20/2015] [Indexed: 01/21/2023]
Abstract
AIM We determined the role of brain Gαi2 proteins in mediating the neural and humoral responses of conscious male Sprague-Dawley rats to acute peripheral sodium challenge. METHODS Rats pre-treated (24-h) intracerebroventricularly with a targeted oligodeoxynucleotide (ODN) (25 μg per 5 μL) to downregulate brain Gαi2 protein expression or a scrambled (SCR) control ODN were challenged with an acute sodium load (intravenous bolus 3 m NaCl; 0.14 mL per 100 g), and cardiovascular parameters were monitored for 120 min. In additional groups, hypothalamic paraventricular nucleus (PVN) Fos immunoreactivity was examined at baseline, 40, and 100 min post-sodium challenge. RESULTS In response to intravenous hypertonic saline (HS), no difference was observed in peak change in mean arterial pressure between groups. In SCR ODN pre-treated rats, arterial pressure returned to baseline by 100 min, while it remained elevated in Gαi2 ODN pre-treated rats (P < 0.05). No difference between groups was observed in sodium-evoked increases in Fos-positive magnocellular neurons or vasopressin release. V1a receptor antagonism failed to block the prolonged elevation of arterial pressure in Gαi2 ODN pre-treated rats. A significantly greater number of Fos-positive ventrolateral parvocellular, lateral parvocellular, and medial parvocellular neurons were observed in SCR vs. Gαi2 ODN pre-treated rats at 40 and 100 min post-HS challenge (P < 0.05). In SCR, but not Gαi2 ODN pre-treated rats, HS evoked suppression of plasma norepinephrine (P < 0.05). CONCLUSION This highlights Gαi2 protein signal transduction as a novel central mechanism acting to differentially influence PVN parvocellular neuronal activation, sympathetic outflow, and arterial pressure in response to acute HS, independently of actions on magnocellular neurons and vasopressin release.
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Affiliation(s)
- C. Y. Carmichael
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular InstituteBoston University School of MedicineBostonMAUSA
| | - A. C. T. Carmichael
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular InstituteBoston University School of MedicineBostonMAUSA
| | - J. T. Kuwabara
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular InstituteBoston University School of MedicineBostonMAUSA
| | - J. T. Cunningham
- Department of Integrative Physiology & AnatomyUniversity of North Texas Health Science CenterFort WorthTXUSA
| | - R. D. Wainford
- Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular InstituteBoston University School of MedicineBostonMAUSA
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Abstract
The etiology of hypertension, a critical public health issue affecting one in three US adults, involves the integration of the actions of multiple organ systems, including the central nervous system. Increased activation of the central nervous system, driving enhanced sympathetic outflow and increased blood pressure, has emerged as a major contributor to the pathogenesis of hypertension. The hypothalamus is a key brain site acting to integrate central and peripheral inputs to ultimately impact blood pressure in multiple disease states that evoke hypertension. This review highlights recent advances that have identified novel signal transduction mechanisms within multiple hypothalamic nuclei (e.g., paraventricular nucleus, arcuate nucleus) acting to drive the pathophysiology of hypertension in neurogenic hypertension, angiotensin II hypertension, salt-sensitive hypertension, chronic intermittent hypoxia, and obesity-induced hypertension. Increased understanding of hypothalamic activity in hypertension has the potential to identify novel targets for future therapeutic interventions designed to treat hypertension.
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30
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Walsh KR, Kuwabara JT, Shim JW, Wainford RD. Norepinephrine-evoked salt-sensitive hypertension requires impaired renal sodium chloride cotransporter activity in Sprague-Dawley rats. Am J Physiol Regul Integr Comp Physiol 2015; 310:R115-24. [PMID: 26608659 DOI: 10.1152/ajpregu.00514.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 11/11/2015] [Indexed: 01/11/2023]
Abstract
Recent studies have implicated a role of norepinephrine (NE) in the activation of the sodium chloride cotransporter (NCC) to drive the development of salt-sensitive hypertension. However, the interaction between NE and increased salt intake on blood pressure remains to be fully elucidated. This study examined the impact of a continuous NE infusion on sodium homeostasis and blood pressure in conscious Sprague-Dawley rats challenged with a normal (NS; 0.6% NaCl) or high-salt (HS; 8% NaCl) diet for 14 days. Naïve and saline-infused Sprague-Dawley rats remained normotensive when placed on HS and exhibited dietary sodium-evoked suppression of peak natriuresis to hydrochlorothiazide. NE infusion resulted in the development of hypertension, which was exacerbated by HS, demonstrating the development of the salt sensitivity of blood pressure [MAP (mmHg) NE+NS: 151 ± 3 vs. NE+HS: 172 ± 4; P < 0.05]. In these salt-sensitive animals, increased NE prevented dietary sodium-evoked suppression of peak natriuresis to hydrochlorothiazide, suggesting impaired NCC activity contributes to the development of salt sensitivity [peak natriuresis to hydrochlorothiazide (μeq/min) Naïve+NS: 9.4 ± 0.2 vs. Naïve+HS: 7 ± 0.1; P < 0.05; NE+NS: 11.1 ± 1.1; NE+HS: 10.8 ± 0.4). NE infusion did not alter NCC expression in animals maintained on NS; however, dietary sodium-evoked suppression of NCC expression was prevented in animals challenged with NE. Chronic NCC antagonism abolished the salt-sensitive component of NE-mediated hypertension, while chronic ANG II type 1 receptor antagonism significantly attenuated NE-evoked hypertension without restoring NCC function. These data demonstrate that increased levels of NE prevent dietary sodium-evoked suppression of the NCC, via an ANG II-independent mechanism, to stimulate the development of salt-sensitive hypertension.
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Affiliation(s)
- Kathryn R Walsh
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Jill T Kuwabara
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Joon W Shim
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Richard D Wainford
- Department of Pharmacology and Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
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Carmichael CY, Wainford RD. Brain Gαi 2 -subunit proteins and the prevention of salt sensitive hypertension. Front Physiol 2015; 6:233. [PMID: 26347659 PMCID: PMC4541027 DOI: 10.3389/fphys.2015.00233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/03/2015] [Indexed: 12/19/2022] Open
Abstract
To counter the development of salt-sensitive hypertension, multiple brain G-protein-coupled receptor (GPCR) systems are activated to facilitate sympathoinhibition, sodium homeostasis, and normotension. Currently there is a paucity of knowledge regarding the role of down-stream GPCR-activated Gα-subunit proteins in these critically important physiological regulatory responses required for long-term blood pressure regulation. We have determined that brain Gαi2-proteins mediate natriuretic and sympathoinhibitory responses produced by acute pharmacological (exogenous central nociceptin/orphanin FQ receptor (NOP) and α2-adrenoceptor activation) and physiological challenges to sodium homeostasis (intravenous volume expansion and 1 M sodium load) in conscious Sprague–Dawley rats. We have demonstrated that in salt-resistant rat phenotypes, high dietary salt intake evokes site-specific up-regulation of hypothalamic paraventricular nucleus (PVN) Gαi2-proteins. Further, we established that PVN Gαi2 protein up-regulation prevents the development of renal nerve-dependent sympathetically mediated salt-sensitive hypertension in Sprague–Dawley and Dahl salt-resistant rats. Additionally, failure to up-regulate PVN Gαi2 proteins during high salt-intake contributes to the pathophysiology of Dahl salt-sensitive (DSS) hypertension. Collectively, our data demonstrate that brain, and likely PVN specific, Gαi2 protein pathways represent a central molecular pathway mediating sympathoinhibitory renal-nerve dependent responses evoked to maintain sodium homeostasis and a salt-resistant phenotype. Further, impairment of this endogenous “anti-hypertensive” mechanism contributes to the pathophysiology of salt-sensitive hypertension.
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Affiliation(s)
- Casey Y Carmichael
- The Department of Pharmacology and Experimental Therapeutics, The Whitaker Cardiovascular Institute, Boston University School of Medicine Boston, MA, USA
| | - Richard D Wainford
- The Department of Pharmacology and Experimental Therapeutics, The Whitaker Cardiovascular Institute, Boston University School of Medicine Boston, MA, USA
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Downregulation of Endogenous Hydrogen Sulfide Pathway Is Involved in Mitochondrion-Related Endothelial Cell Apoptosis Induced by High Salt. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:754670. [PMID: 26078816 PMCID: PMC4442413 DOI: 10.1155/2015/754670] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 12/25/2014] [Accepted: 12/26/2014] [Indexed: 11/17/2022]
Abstract
Background. The study aimed to investigate whether endogenous H2S pathway was involved in high-salt-stimulated mitochondria-related vascular endothelial cell (VEC) apoptosis. Methods. Cultured human umbilical vein endothelial cells (HUVECs) were used in the study. H2S content in the supernatant was detected. Western blot was used to detect expression of cystathionine gamma-lyase (CSE), cleaved-caspase-3, and mitochondrial and cytosolic cytochrome c (cytc). Fluorescent probes were used to quantitatively detect superoxide anion generation and measure the in situ superoxide anion generation in HUVEC. Mitochondrial membrane pore opening, mitochondrial membrane potential, and caspase-9 activities were measured. The cell apoptosis was detected by cell death ELISA and TdT-mediated dUTP nick end labeling (TUNEL) methods. Results. High-salt treatment downregulated the endogenous VEC H2S/CSE pathway, in association with increased generation of oxygen free radicals, decreased mitochondrial membrane potential, enhanced the opening of mitochondrial membrane permeability transition pore and leakage of mitochondrial cytc, activated cytoplasmic caspase-9 and caspase-3 and subsequently induced VEC apoptosis. However, supplementation of H2S donor markedly inhibited VEC oxidative stress and mitochondria-related VEC apoptosis induced by high salt. Conclusion. H2S/CSE pathway is an important endogenous defensive system in endothelial cells antagonizing high-salt insult. The protective mechanisms for VEC damage might involve inhibiting oxidative stress and protecting mitochondrial injury.
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