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Jelinic M, Jackson KL, O'Sullivan K, Singh J, Giddy T, Deo M, Parry LJ, Ritchie RH, Woodman OL, Head GA, Leo CH, Qin CX. Endothelium-dependent relaxation is impaired in Schlager hypertensive (BPH/2J) mice by region-specific mechanisms in conductance and resistance arteries. Life Sci 2023; 320:121542. [PMID: 36871935 DOI: 10.1016/j.lfs.2023.121542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/21/2023] [Accepted: 02/27/2023] [Indexed: 03/07/2023]
Abstract
AIMS Endothelial dysfunction and arterial stiffness are hallmarks of hypertension, and major risk factors for cardiovascular disease. BPH/2J (Schlager) mice are a genetic model of spontaneous hypertension, but little is known about the vascular pathophysiology of these mice and the region-specific differences between vascular beds. Therefore, this study compared the vascular function and structure of large conductance (aorta and femoral) and resistance (mesenteric) arteries of BPH/2J mice with their normotensive BPN/2J counterparts. MAIN METHODS Blood pressure was measured in BPH/2J and BPN/3J mice via pre-implanted radiotelemetry probes. At endpoint, vascular function and passive mechanical wall properties were assessed using wire and pressure myography, qPCR and histology. KEY FINDINGS Mean arterial blood pressure was elevated in BPH/2J mice compared to BPN/3J controls. Endothelium-dependent relaxation to acetylcholine was attenuated in both the aorta and mesenteric arteries of BPH/2J mice, but through different mechanisms. In the aorta, hypertension reduced the contribution of prostanoids. Conversely, in the mesenteric arteries, hypertension reduced the contribution of both nitric oxide and endothelium-dependent hyperpolarization. Hypertension reduced volume compliance in both femoral and mesenteric arteries, but hypertrophic inward remodelling was only observed in the mesenteric arteries of BPH/2J mice. SIGNIFICANCE This is the first comprehensive investigation of vascular function and structural remodelling in BPH/2J mice. Overall, hypertensive BPH/2J mice exhibited endothelial dysfunction and adverse vascular remodelling in the macro- and microvasculature, underpinned by distinct region-specific mechanisms. This highlights BPH/2J mice as a highly suitable model for evaluating novel therapeutics to treat hypertension-associated vascular dysfunction.
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Affiliation(s)
- Maria Jelinic
- Centre for Cardiovascular Biology and Disease Research, Department of Microbiology, Anatomy, Physiology & Pharmacology, La Trobe University, Bundoora, VIC, Australia; School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | - Kristy L Jackson
- Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia; Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Kelly O'Sullivan
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | - Jaideep Singh
- Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia; Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Thomas Giddy
- Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Minh Deo
- Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia; Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Laura J Parry
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia; School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Rebecca H Ritchie
- Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia; Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Owen L Woodman
- Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Geoffrey A Head
- Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Chen Huei Leo
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia; Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia; Science, Math and Technology, Singapore University of Technology & Design, Singapore.
| | - Cheng Xue Qin
- Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia; Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia.
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Correa BHM, Becari L, Peliky Fontes MA, Simões-e-Silva AC, Kangussu LM. Involvement of the Renin-Angiotensin System in Stress: State of the Art and Research Perspectives. Curr Neuropharmacol 2022; 20:1212-1228. [PMID: 34554902 PMCID: PMC9886820 DOI: 10.2174/1570159x19666210719142300] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/19/2021] [Accepted: 07/09/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Along with other canonical systems, the renin-angiotensin system (RAS) has shown important roles in stress. This system is a complex regulatory proteolytic cascade composed of various enzymes, peptides, and receptors. Besides the classical (ACE/Ang II/AT1 receptor) and the counter-regulatory (ACE2/Ang-(1-7)/Mas receptor) RAS axes, evidence indicates that nonclassical components, including Ang III, Ang IV, AT2 and AT4, can also be involved in stress. OBJECTIVE AND METHODS This comprehensive review summarizes the current knowledge on the participation of RAS components in different adverse environmental stimuli stressors, including air jet stress, cage switch stress, restraint stress, chronic unpredictable stress, neonatal isolation stress, and post-traumatic stress disorder. RESULTS AND CONCLUSION In general, activation of the classical RAS axis potentiates stress-related cardiovascular, endocrine, and behavioral responses, while the stimulation of the counter-regulatory axis attenuates these effects. Pharmacological modulation in both axes is optimistic, offering promising perspectives for stress-related disorders treatment. In this regard, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are potential candidates already available since they block the classical axis, activate the counter-regulatory axis, and are safe and efficient drugs.
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Affiliation(s)
- Bernardo H. M. Correa
- Department of Morphology, Biological Sciences Institute, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil;
| | - Luca Becari
- Department of Morphology, Biological Sciences Institute, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil;
| | - Marco Antônio Peliky Fontes
- Department of Physiology & Biophysics - Biological Sciences Institute, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil;
| | - Ana Cristina Simões-e-Silva
- Department of Pediatrics, Faculty of Medicine, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Lucas M. Kangussu
- Department of Morphology, Biological Sciences Institute, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil; ,Address correspondence to this author at the Department of Morphology, Biological Sciences Institute – Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil; Tel: (+55-31) 3409-2772; E-mail:
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3
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Hall S, Ward ND, Patel R, Amin-Javaheri A, Lanford H, Grespin RT, Couch C, Xiong Y, Mukherjee R, Jones JA, Ruddy JM. Mechanical activation of the angiotensin II type 1 receptor contributes to abdominal aortic aneurysm formation. JVS Vasc Sci 2021; 2:194-206. [PMID: 34761239 PMCID: PMC8567200 DOI: 10.1016/j.jvssci.2021.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 07/14/2021] [Indexed: 12/22/2022] Open
Abstract
Objective The angiotensin II type 1 receptor (AT1R) can be activated under conditions of mechanical stretch in some cellular systems. Whether this activity influences signaling within the abdominal aorta to promote to abdominal aortic aneurysm (AAA) development remains unknown. We evaluated the hypothesis that mechanical AT1R activation can occur under conditions of hypertension (HTN) and contribute to AAA formation. Methods BPH/2 mice, which demonstrate spontaneous neurogenic, low-renin HTN, and normotensive BPN/3 mice underwent AAA induction via the calcium chloride model, with or without an osmotic minipump delivering 30 mg/kg/d of the AT1R blocker Losartan. Systolic blood pressure (SBP) was measured at baseline and weekly via a tail cuff. The aortic diameter (AoD) was measured at baseline and terminal surgery at 21 days by digital microscopy. Aortic tissue was harvested for immunoblotting (phosphorylated extracellular signal-regulated kinase-1 and -2 [pERK1/2] to ERK1/2 ratio) and expressed as the fold-change from the BPN/3 control mice. Aortic vascular smooth muscle cells (VSMCs) underwent stretch with or without Losartan (1 μM) treatment to assess the mechanical stimulation of ERK1/2 activity. Statistical analysis of the blood pressure, AoD, and VSMC ERK1/2 activity was performed using analysis of variance. However, the data distribution was determined to be log-normal (Shapiro-Wilk test) for ERK1/2 activity. Therefore, it was logarithmically transformed before analysis of variance. Results At baseline, the SBP was elevated in the BPH/2 mice relative to the BPN/3 mice (P < .05). Losartan treatment significantly reduced the SBP in both mouse strains (P < .05). AAA induction did not affect the SBP. At 21 days after induction, the percentage of increase in the AoD from baseline was significantly greater in the BPH/2 mice than in the BPN/3 mice (101.28% ± 4.19% vs 75.59% ± 1.67% above baseline; P < .05). Losartan treatment significantly attenuated AAA growth in both BPH/2 and BPN/3 mice (33.88% ± 2.97% and 43.96% ± 3.05% above baseline, respectively; P < .05). ERK1/2 activity was increased approximately fivefold in the BPH/2 control mice relative to the BPN/3 control mice (P < .05). In the BPH/2 and BPN/3 mice with AAA, ERK1/2 activity was significantly increased relative to the respective baseline control (P < .05) and effectively reduced by concomitant Losartan therapy (P < .05). Biaxial stretch of the VSMCs in the absence of angiotensin II demonstrated increased ERK1/2 activation (P < .05 vs static control), which was significantly inhibited by Losartan. Conclusions In BPH/2 mice with spontaneous neurogenic, low-renin HTN, AAA growth was amplified compared with the normotensive control and was effectively attenuated using Losartan. ERK1/2 activity was significantly elevated in the BPH/2 mice and after AAA induction in the normotensive and hypertensive mice but was attenuated by Losartan treatment. These data suggest that AT1R activation contributes to AAA development. Therefore, further investigation into this signaling pathway could establish targets for pharmacotherapeutic engineering to slow AAA growth. (JVS-Vascular Science 2021;2:194-206.). Clinical Relevance Hypertension (HTN) and abdominal aortic aneurysm (AAA) have been epidemiologically linked for decades; however, a biomechanical link has not yet been identified. Using a murine model of spontaneous neurogenic HTN experimentally demonstrated to have low circulating renin, mechanical activation of the angiotensin II type 1 receptor (AT1R) was identified with elevated blood pressure and AAA induction. HTN amplified AAA growth. However, more importantly, blocking the activation of AT1R with the angiotensin receptor blocker Losartan effectively abrogated AAA development. Although inhibiting the production of angiotensin II has previously been unsuccessful in altering AAA growth, the results from the present study suggest that blocking the activation of AT1R through direct ligand binding or mechanical stimulation might alter aortic wall signaling and warrants further investigation.
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Affiliation(s)
- SarahRose Hall
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Nicholas D Ward
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Raj Patel
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Armaan Amin-Javaheri
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC
| | - Hayes Lanford
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - R Tyler Grespin
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Christine Couch
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC
| | - Ying Xiong
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC
| | - Rupak Mukherjee
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC.,Ralph H. Johnson VA Medical Center, Charleston, SC
| | - Jeffrey A Jones
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC.,Ralph H. Johnson VA Medical Center, Charleston, SC
| | - Jean Marie Ruddy
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC.,Ralph H. Johnson VA Medical Center, Charleston, SC
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Lin SR, Lin SY, Chen CC, Fu YS, Weng CF. Exploring a New Natural Treating Agent for Primary Hypertension: Recent Findings and Forthcoming Perspectives. J Clin Med 2019; 8:jcm8112003. [PMID: 31744165 PMCID: PMC6912567 DOI: 10.3390/jcm8112003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/14/2019] [Accepted: 11/14/2019] [Indexed: 12/13/2022] Open
Abstract
Primary hypertension describes abnormally-high systolic/diastolic blood pressure in a resting condition caused by various genetic or environmental risk factors. Remarkably, severe complications, such as ischemic cardiovascular disease, stroke, and chronic renal disease have led to primary hypertension becoming a huge burden for almost one-third of the total population. Medication is the major regimen for treating primary hypertension; however, recent medications may have adverse effects that attenuate energy levels. Hence, the search for new hypotensive agents from folk or traditional medicine may be fruitful in the discovery and development of new drugs. This review assembles recent findings for natural antihypertensive agents, extracts, or decoctions published in PubMed, and provides insights into the search for new hypotensive compounds based on blood-pressure regulating mechanisms, including the renin-angiotensin-aldosterone system and the sympathetic/adrenergic receptor/calcium channel system.
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Affiliation(s)
- Shian-Ren Lin
- Department of Life Science and Institute of Biotechnology, National Dong Hwa University, Hualien 97401, Taiwan; (S.-R.L.); (C.-C.C.)
- Graduate Institute of Cancer Biology and Drug Discovery, Taipei Medical University, Taipei 110, Taiwan
| | - Shiuan-Yea Lin
- Department of Anatomy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Ching-Cheng Chen
- Department of Life Science and Institute of Biotechnology, National Dong Hwa University, Hualien 97401, Taiwan; (S.-R.L.); (C.-C.C.)
- Camillian Saint Mary’s Hospital Luodong,160 Zhongzheng S. Rd. Luodong, Yilan 26546, Taiwan
| | - Yaw-Syan Fu
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Center for Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Correspondence: (Y.-S.F.); (C.-F.W.); Tel.: +886-3-890-3609 (C.-F.W.); Fax: +886-3-890-0163 (C.-F.W.)
| | - Ching-Feng Weng
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Basic Medical Science, Center for Transitional Medicine, Xiamen Medical College, Xiamen 361023, China
- Correspondence: (Y.-S.F.); (C.-F.W.); Tel.: +886-3-890-3609 (C.-F.W.); Fax: +886-3-890-0163 (C.-F.W.)
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5
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Jackson KL, Head GA, Gueguen C, Stevenson ER, Lim K, Marques FZ. Mechanisms Responsible for Genetic Hypertension in Schlager BPH/2 Mice. Front Physiol 2019; 10:1311. [PMID: 31681017 PMCID: PMC6813185 DOI: 10.3389/fphys.2019.01311] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/30/2019] [Indexed: 01/18/2023] Open
Abstract
It has been 45 years since Gunther Schlager used a cross breeding program in mice to develop inbred strains with high, normal, and low blood pressure (BPH/2, BPN/3, and BPL/1 respectively). Thus, it is timely to gather together the studies that have characterized and explored the mechanisms associated with the hypertension to take stock of exactly what is known and what remains to be determined. Growing evidence supports the notion that the mechanism of hypertension in BPH/2 mice is predominantly neurogenic with some of the early studies showing aberrant brain noradrenaline levels in BPH/2 compared with BPN/3. Analysis of the adrenal gland using microarray suggested an association with the activity of the sympathetic nervous system. Indeed, in support of this, there is a larger depressor response to ganglion blockade, which reduced blood pressure in BPH/2 mice to the same level as BPN/3 mice. Greater renal tyrosine hydroxylase staining and greater renal noradrenaline levels in BPH/2 mice suggest sympathetic hyperinnervation of the kidney. Renal denervation markedly reduced the blood pressure in BPH/2 but not BPN/3 mice, confirming the importance of renal sympathetic nervous activity contributing to the hypertension. Further, there is an important contribution to the hypertension from miR-181a and renal renin in this strain. BPH/2 mice also display greater neuronal activity of amygdalo-hypothalamic cardiovascular regulatory regions. Lesions of the medial nucleus of the amygdala reduced the hypertension in BPH/2 mice and abolished the strain difference in the effect of ganglion blockade, suggesting a sympathetic mechanism. Further studies suggest that aberrant GABAergic inhibition may play a role since BPH/2 mice have low GABAA receptor δ, α4 and β2 subunit mRNA expression in the hypothalamus, which are predominantly involved in promoting tonic neuronal inhibition. Allopregnanolone, an allosteric modulator of GABAA receptors, which increase the expression of these subunits in the amygdala and hypothalamus, is shown to reduce the hypertension and sympathetic nervous system contribution in BPH/2 mice. Thus far, evidence suggests that BPH/2 mice have aberrant GABAergic inhibition, which drives neuronal overactivity within amygdalo-hypothalamic brain regions. This overactivity is responsible for the greater sympathetic contribution to the hypertension in BPH/2 mice, thus making this an ideal model of neurogenic hypertension.
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Affiliation(s)
- Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Cindy Gueguen
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Emily R Stevenson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Kyungjoon Lim
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Francine Z Marques
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Hypertension Research Laboratory, School of Biological Sciences, Monash University, Clayton, VIC, Australia
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GRK2 knockdown in mice exacerbates kidney injury and alters renal mechanisms of blood pressure regulation. Sci Rep 2018; 8:11415. [PMID: 30061705 PMCID: PMC6065385 DOI: 10.1038/s41598-018-29876-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023] Open
Abstract
The renin-angiotensin system regulates blood pressure and fluid balance in the body primarily via angiotensin receptor 1 (AT1R). Renal AT1R was found to be primarily responsible for Ang II-mediated hypertension. G protein-coupled receptor kinase 2 (GRK2) modulates AT1R desensitization and increased GRK2 protein expression is reported in hypertensive patients. However, the consequences of GRK2 inhibition on kidney functions remain unknown. We employed shGRK2 knockdown mice (shGRK2 mice) to test the role of GRK2 in kidney development and function that can be ultimately linked to the hypertensive phenotype detected in shGRK2 mice. GRK2 knockdown reduced kidney size, nephrogenesis and glomerular count, and impaired glomerular filtration. Glomerular damage in adult shGRK2 mice was associated with increased renin- and AT1R-mediated production of reactive oxygen species. The AT1R blocker, Losartan, normalized elevated blood pressure and markedly improved glomerular filtration in the shGRK2 knockdown mice. Our findings provide evidence for the crucial role of GRK2 in renal regulation of blood pressure. It also suggests that the detrimental outcomes of GRK2 inhibitors on the kidney should be carefully examined when used as antihypertensive.
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Jackson KL, Marques FZ, Lim K, Davern PJ, Head GA. Circadian Differences in the Contribution of the Brain Renin-Angiotensin System in Genetically Hypertensive Mice. Front Physiol 2018; 9:231. [PMID: 29615926 PMCID: PMC5868475 DOI: 10.3389/fphys.2018.00231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/01/2018] [Indexed: 11/21/2022] Open
Abstract
Objective: Genetically hypertensive BPH/2J mice are recognized as a neurogenic model of hypertension, primarily based on sympathetic overactivity and greater neuronal activity in cardiovascular regulatory brain regions. Greater activity of the central renin angiotensin system (RAS) and reactive oxygen species (ROS) reportedly contribute to other models of hypertension. Importantly the peripheral RAS contributes to the hypertension in BPH/2J mice, predominantly during the dark period of the 24 h light cycle. The aim of the present study was to determine whether central AT1 receptor stimulation and the associated ROS signaling contribute to hypertension in BPH/2J mice in a circadian dependent manner. Methods: Blood pressure (BP) was measured in BPH/2J and normotensive BPN/3J mice (n = 7–8) via pre-implanted telemetry devices. Acute intracerebroventricular (ICV) microinjections of AT1 receptor antagonist, candesartan, and the superoxide dismutase (SOD) mimetic, tempol, were administered during the dark and light period of the 24 h light cycle via a pre-implanted ICV guide cannula. In separate mice, the BP effect of ICV infusion of the AT1 receptor antagonist losartan for 7 days was compared with subcutaneous infusion to determine the contribution of the central RAS to hypertension in BPH/2J mice. Results: Candesartan administered ICV during the dark period induced depressor responses which were 40% smaller in BPH/2J than BPN/3J mice (Pstrain < 0.05), suggesting AT1 receptor stimulation may contribute less to BP maintenance in BPH/2J mice. During the light period candesartan had minimal effect on BP in either strain. ICV tempol had comparable effects on BP between strains during the light and dark period (Pstrain > 0.08), suggesting ROS signaling is also not contributing to the hypertension in BPH/2J mice. Chronic ICV administration of losartan (22 nmol/h) had minimal effect on BPN/3J mice. By contrast in BPH/2J mice, both ICV and subcutaneously administered losartan induced similar hypotensive responses (−12.1 ± 1.8 vs. −14.7 ± 1.8 mmHg, Proute = 0.31). Conclusion: While central effects of peripheral losartan cannot be excluded, we suggest the hypotensive effect of chronic ICV losartan was likely peripherally mediated. Thus, based on both acute and chronic AT1 receptor inhibition and acute ROS inhibition, our findings suggest that greater activation of central AT1 receptors or ROS are unlikely to be mediating the hypertension in BPH/2J mice.
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Affiliation(s)
- Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Francine Z Marques
- Department of Pharmacology, Monash University, Victoria, VIC, Australia.,Heart Failure Research Group, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Kyungjoon Lim
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia.,Department of Physiology, Anatomy and Microbiology, Latrobe University, Bundoora, VIC, Australia
| | - Pamela J Davern
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia.,Department of Pharmacology, Monash University, Victoria, VIC, Australia
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8
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Nelson JW, Ferdaus MZ, McCormick JA, Minnier J, Kaul S, Ellison DH, Barnes AP. Endothelial transcriptomics reveals activation of fibrosis-related pathways in hypertension. Physiol Genomics 2018; 50:104-116. [PMID: 29212850 DOI: 10.1152/physiolgenomics.00111.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hypertension poses a significant challenge to vasculature homeostasis and stands as the most common cardiovascular disease in the world. Its effects are especially profound on endothelial cells that form the inner lining of the vasculature and are directly exposed to the effects of excess pressure. Here, we characterize the in vivo transcriptomic response of cardiac endothelial cells to hypertension by rapidly isolating these cells from the spontaneous hypertension mouse model BPH/2J and its normotensive BPN/3J control strain and performing and RNA sequencing on both. Comparison of transcriptional differences between these groups reveals statistically significant changes in cellular pathways consistent with cardiac fibrosis found in hypertensive animals. Importantly, many of the fibrosis-linked genes identified also differ significantly between juvenile prehypertensive and adult hypertensive BPH/2J mice, suggesting that these transcriptional differences are hypertension related. We examined the dynamic nature of these transcriptional changes by testing whether blood pressure normalization using either a calcium channel blocker (amlodipine) or a angiotensin II receptor blocker (losartan) is able to reverse these expression patterns associated with hypertension. We find that blood pressure reduction is capable of reversing some gene-expression patterns, while other transcripts are recalcitrant to therapeutic intervention. This illuminates the possibility that unmanaged hypertension may irreversibly alter some endothelial transcriptional patterns despite later intervention. This study quantifies how endothelial cells are remodeled at the molecular level in cardiovascular pathology and advances our understanding of the transcriptional events associated with endothelial response to hypertensive challenge.
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Affiliation(s)
- Jonathan W Nelson
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Mohammed Z Ferdaus
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon
| | - James A McCormick
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon
| | - Jessica Minnier
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Sanjiv Kaul
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - David H Ellison
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon.,Department of Medicine, Oregon Clinical and Translational Research Institute, Oregon Health & Science University , Portland, Oregon
| | - Anthony P Barnes
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
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9
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Good ME, Chiu YH, Poon IKH, Medina CB, Butcher JT, Mendu SK, DeLalio LJ, Lohman AW, Leitinger N, Barrett E, Lorenz UM, Desai BN, Jaffe IZ, Bayliss DA, Isakson BE, Ravichandran KS. Pannexin 1 Channels as an Unexpected New Target of the Anti-Hypertensive Drug Spironolactone. Circ Res 2017; 122:606-615. [PMID: 29237722 DOI: 10.1161/circresaha.117.312380] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 12/06/2017] [Accepted: 12/12/2017] [Indexed: 12/16/2022]
Abstract
RATIONALE Resistant hypertension is a major health concern with unknown cause. Spironolactone is an effective antihypertensive drug, especially for patients with resistant hypertension, and is considered by the World Health Organization as an essential medication. Although spironolactone can act at the mineralocorticoid receptor (MR; NR3C2), there is increasing evidence of MR-independent effects of spironolactone. OBJECTIVE Here, we detail the unexpected discovery that Panx1 (pannexin 1) channels could be a relevant in vivo target of spironolactone. METHODS AND RESULTS First, we identified spironolactone as a potent inhibitor of Panx1 in an unbiased small molecule screen, which was confirmed by electrophysiological analysis. Next, spironolactone inhibited α-adrenergic vasoconstriction in arterioles from mice and hypertensive humans, an effect dependent on smooth muscle Panx1, but independent of the MR NR3C2. Last, spironolactone acutely lowered blood pressure, which was dependent on smooth muscle cell expression of Panx1 and independent of NR3C2. This effect, however, was restricted to steroidal MR antagonists as a nonsteroidal MR antagonist failed to reduced blood pressure. CONCLUSIONS These data suggest new therapeutic modalities for resistant hypertension based on Panx1 inhibition.
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Affiliation(s)
- Miranda E Good
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Yu-Hsin Chiu
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Ivan K H Poon
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Christopher B Medina
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Joshua T Butcher
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Suresh K Mendu
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Leon J DeLalio
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Alexander W Lohman
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Norbert Leitinger
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Eugene Barrett
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Ulrike M Lorenz
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Bimal N Desai
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Iris Z Jaffe
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Douglas A Bayliss
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Brant E Isakson
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.).
| | - Kodi S Ravichandran
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
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Didion SP. A novel genetic model to explore the Brenner hypothesis: Linking nephron endowment and number with hypertension. Med Hypotheses 2017; 106:6-9. [DOI: 10.1016/j.mehy.2017.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/26/2017] [Indexed: 10/19/2022]
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Faraco G, Sugiyama Y, Lane D, Garcia-Bonilla L, Chang H, Santisteban MM, Racchumi G, Murphy M, Van Rooijen N, Anrather J, Iadecola C. Perivascular macrophages mediate the neurovascular and cognitive dysfunction associated with hypertension. J Clin Invest 2016; 126:4674-4689. [PMID: 27841763 DOI: 10.1172/jci86950] [Citation(s) in RCA: 210] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 09/30/2016] [Indexed: 01/05/2023] Open
Abstract
Hypertension is a leading risk factor for dementia, but the mechanisms underlying its damaging effects on the brain are poorly understood. Due to a lack of energy reserves, the brain relies on continuous delivery of blood flow to its active regions in accordance with their dynamic metabolic needs. Hypertension disrupts these vital regulatory mechanisms, leading to the neuronal dysfunction and damage underlying cognitive impairment. Elucidating the cellular bases of these impairments is essential for developing new therapies. Perivascular macrophages (PVMs) represent a distinct population of resident brain macrophages that serves key homeostatic roles but also has the potential to generate large amounts of reactive oxygen species (ROS). Here, we report that PVMs are critical in driving the alterations in neurovascular regulation and attendant cognitive impairment in mouse models of hypertension. This effect was mediated by an increase in blood-brain barrier permeability that allowed angiotensin II to enter the perivascular space and activate angiotensin type 1 receptors in PVMs, leading to production of ROS through the superoxide-producing enzyme NOX2. These findings unveil a pathogenic role of PVMs in the neurovascular and cognitive dysfunction associated with hypertension and identify these cells as a putative therapeutic target for diseases associated with cerebrovascular oxidative stress.
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Rajapakse NW, Karim F, Evans RG, Kaye DM, Head GA. Augmented Endothelial-Specific L-Arginine Transport Blunts the Contribution of the Sympathetic Nervous System to Obesity Induced Hypertension in Mice. PLoS One 2015; 10:e0131424. [PMID: 26186712 PMCID: PMC4505872 DOI: 10.1371/journal.pone.0131424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 06/02/2015] [Indexed: 11/18/2022] Open
Abstract
Augmenting endothelial specific transport of the nitric oxide precursor L-arginine via cationic amino acid transporter-1 (CAT1) can prevent obesity related hypertension. We tested the hypotheses that CAT1 overexpression prevents obesity-induced hypertension by buffering the influence of the sympathetic nervous system (SNS) on the maintenance of arterial pressure and by buffering pressor responses to stress. Wild type (WT; n=13) and CAT1 overexpressing mice (CAT+; n=13) were fed a normal or a high fat diet for 20 weeks. Mice fed a high fat diet were returned to the control diet before experiments commenced. Baseline mean arterial pressure (MAP) and effects of restraint-, shaker- and almond feeding-stress and ganglionic blockade (pentolinium; 5 mg/kg; i.p.) on MAP were determined in conscious mice. Fat feeding increased body weight to a similar extent in WT and CAT+ but MAP was greater only in WT compared to appropriate controls (by 29%). The depressor response to pentolinium was 65% greater in obese WT than lean WT (P < 0.001), but was similar in obese and lean CAT+ (P = 0.65). In lean WT and CAT+, pressor responses to shaker and feeding stress, but not restraint stress, were less in the latter genotype compared to the former (P ≤ 0.001). Pressor responses to shaker and feeding stress were less in obese WT than lean WT (P ≤ 0.001), but similar in obese and lean CAT+. The increase in MAP in response to restraint stress was less in obese WT (22 ± 2%), but greater in obese CAT+ (37 ± 2%), when compared to respective lean WT (31 ± 3%) and lean CAT+ controls (27 ± 2%; P ≤ 0.02). We conclude that CAT1 overexpression prevents obesity-induced hypertension by reducing the influence of the SNS on the maintenance of arterial pressure but not by buffering pressor responses to stress.
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Affiliation(s)
- Niwanthi W Rajapakse
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia; Department of Physiology, Monash University, Melbourne, Australia
| | - Florian Karim
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Roger G Evans
- Department of Physiology, Monash University, Melbourne, Australia
| | - David M Kaye
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Geoffrey A Head
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
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13
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Durand MT, Becari C, Tezini GCSV, Fazan R, Oliveira M, Guatimosim S, Prado VF, Prado MAM, Salgado HC. Autonomic cardiocirculatory control in mice with reduced expression of the vesicular acetylcholine transporter. Am J Physiol Heart Circ Physiol 2015; 309:H655-62. [PMID: 26092977 DOI: 10.1152/ajpheart.00114.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/15/2015] [Indexed: 01/13/2023]
Abstract
In cardiovascular diseases, sympathetic tone has been comprehensively studied, whereas parasympathetic tone has received minor attention. The vesicular ACh transporter (VAChT) knockdown homozygous (VAChT KD(HOM)) mouse is a useful model for examining the cardiocirculatory sympathovagal balance. Therefore, we investigated whether cholinergic dysfunction caused by reduced VAChT expression could adversely impact hemodynamic parameter [arterial pressure (AP) and heart rate (HR)] daily oscillation, baroreflex sensitivity, hemodynamic variability, sympathovagal balance, and cardiovascular reactivity to restraint stress. Wild-type and VAChT KD(HOM) mice were anesthetized for telemetry transmitter implantation, and APs and HRs were recorded 10 days after surgical recovery. Changes in HR elicited by methylatropine and propranolol provided the indexes of sympathovagal tone. Cardiovascular reactivity in response to a restraint test was examined 24 h after continuous recordings of AP and HR. VAChT KD(HOM) mice exhibited reduced parasympathetic and elevated sympathetic tone. Daily oscillations of AP and HR as well as AP variability were similar between groups. Nevertheless, HR variability, patterns with two dissimilar variations from symbolic analysis, and baroreflex sensitivity were reduced in VAChT KD(HOM) mice. The change in mean AP due to restraint stress was greater in VAChT KD(HOM) mice, whereas the tachycardic response was not. These findings demonstrate that the cholinergic dysfunction present in the VAChT KD(HOM) mouse did not adversely impact basal hemodynamic parameters but promoted autonomic imbalance, an attenuation of baroreflex sensitivity, and a greater pressure response to restraint stress. These results provide a framework for understanding how autonomic imbalance impacts cardiovascular function.
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Affiliation(s)
- Marina T Durand
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Christiane Becari
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Geisa C S V Tezini
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rubens Fazan
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Mauro Oliveira
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; and
| | - Vania F Prado
- Robarts Research Institute, Department of Anatomy and Cell Biology and Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Marco A M Prado
- Robarts Research Institute, Department of Anatomy and Cell Biology and Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Helio C Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil;
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Jackson KL, Palma-Rigo K, Nguyen-Huu TP, Davern PJ, Head GA. Major Contribution of the Medial Amygdala to Hypertension in BPH/2J Genetically Hypertensive Mice. Hypertension 2014; 63:811-8. [DOI: 10.1161/hypertensionaha.113.02020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kristy L. Jackson
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Kesia Palma-Rigo
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Thu-Phuc Nguyen-Huu
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Pamela J. Davern
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Geoffrey A. Head
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
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15
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GABAA receptor dysfunction contributes to high blood pressure and exaggerated response to stress in Schlager genetically hypertensive mice. J Hypertens 2014; 32:352-62. [DOI: 10.1097/hjh.0000000000000015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Jackson KL, Marques FZ, Watson AMD, Palma-Rigo K, Nguyen-Huu TP, Morris BJ, Charchar FJ, Davern PJ, Head GA. A novel interaction between sympathetic overactivity and aberrant regulation of renin by miR-181a in BPH/2J genetically hypertensive mice. Hypertension 2013; 62:775-81. [PMID: 23897069 DOI: 10.1161/hypertensionaha.113.01701] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Genetically hypertensive mice (BPH/2J) are hypertensive because of an exaggerated contribution of the sympathetic nervous system to blood pressure. We hypothesize that an additional contribution to elevated blood pressure is via sympathetically mediated activation of the intrarenal renin-angiotensin system. Our aim was to determine the contribution of the renin-angiotensin system and sympathetic nervous system to hypertension in BPH/2J mice. BPH/2J and normotensive BPN/3J mice were preimplanted with radiotelemetry devices to measure blood pressure. Depressor responses to ganglion blocker pentolinium (5 mg/kg i.p.) in mice pretreated with the angiotensin-converting enzyme inhibitor enalaprilat (1.5 mg/kg i.p.) revealed a 2-fold greater sympathetic contribution to blood pressure in BPH/2J mice during the active and inactive period. However, the depressor response to enalaprilat was 4-fold greater in BPH/2J compared with BPN/3J mice, but only during the active period (P=0.01). This was associated with 1.6-fold higher renal renin messenger RNA (mRNA; P=0.02) and 0.8-fold lower abundance of micro-RNA-181a (P=0.03), identified previously as regulating human renin mRNA. Renin mRNA levels correlated positively with depressor responses to pentolinium (r=0.99; P=0.001), and BPH/2J mice had greater renal sympathetic innervation density as identified by tyrosine hydroxylase staining of cortical tubules. Although there is a major sympathetic contribution to hypertension in BPH/2J mice, the renin-angiotensin system also contributes, doing so to a greater extent during the active period and less during the inactive period. This is the opposite of the normal renin-angiotensin system circadian pattern. We suggest that renal hyperinnervation and enhanced sympathetically induced renin synthesis mediated by lower micro-RNA-181a contributes to hypertension in BPH/2J mice.
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Affiliation(s)
- Kristy L Jackson
- Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, P.O. Box 6492, St Kilda Rd Central, Melbourne, Victoria 8008, Australia.
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Marques FZ, Morris BJ. Neurogenic hypertension: revelations from genome-wide gene expression profiling. Curr Hypertens Rep 2013; 14:485-91. [PMID: 22639016 DOI: 10.1007/s11906-012-0282-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is now good evidence for a role of the sympathetic nervous system in the etiology of essential hypertension in humans. Although genetic variation is expected to underlie the elevated sympathetic outflow in this complex polygenic condition, only limited information has emerged from classic molecular genetic studies. Recently, progress has been made in understanding neurogenic aspects by determination of global alterations in gene expression in key brain regions of animal models of neurogenic hypertension. Such genome-wide expression studies in the hypothalamus and brainstem support roles for factors such as neuronal nitric oxide synthase, inflammation and reactive oxygen species. A role for non-coding RNAs such as microRNAs, and epigenetic alterations await exploration. Ongoing novel approaches should provide a better understanding of the processes responsible for the increased sympathetic outflow in animal models, as well as essential hypertension in humans. Such information may lead to better therapies for neurogenic hypertension in humans.
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Palma-Rigo K, Bassi JK, Nguyen-Huu TP, Jackson KL, Davern PJ, Chen D, Elghozi JL, Thomas WG, Allen AM, Head GA. Angiotensin 1A receptors transfected into caudal ventrolateral medulla inhibit baroreflex gain and stress responses. Cardiovasc Res 2012; 96:330-9. [PMID: 22869618 DOI: 10.1093/cvr/cvs252] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AIMS The caudal ventrolateral medulla (CVLM) is important for autonomic regulation and is rich in angiotensin II type 1A receptors (AT(1A)R). To determine their function, we examined whether the expression of AT(1A)R in the CVLM of mice lacking AT(1A)R (AT(1A)(-/-)) alters baroreflex sensitivity and cardiovascular responses to stress. METHODS AND RESULTS Bilateral microinjections into the CVLM of AT(1A)(-/-) mice of lentivirus with the phox-2 selective promoter (PRSx8) were made to express either AT(1A)R (Lv-PRSx8-AT(1A)) or green fluorescent protein (Lv-PRSx8-GFP) as a control. Radiotelemetry was used to record mean arterial pressure (MAP), heart rate (HR), and locomotor activity. Following injection of Lv-PRSx8-GFP, robust neuronal expression of GFP was observed with ∼60% of the GFP-positive cells also expressing the catecholamine-synthetic enzyme tyrosine hydroxylase. After 5 weeks, there were no differences in MAP or HR between groups, but the Lv-PRSx8-AT(1A)- injected mice showed reduced baroreflex sensitivity (-25%, P = 0.003) and attenuated pressor responses to cage-switch and restraint stress compared with the Lv-PRSx8-GFP-injected mice. Reduced MAP mid-frequency power during cage-switch stress reflected attenuated sympathetic activation (Pgroup × stress = 0.04). Fos-immunohistochemistry indicated greater activation of forebrain and hypothalamic neurons in the Lv-PRSx8-AT(1A) mice compared with the control. CONCLUSION The expression of AT(1A)R in CVLM neurons, including A1 neurons, while having little influence on the basal blood pressure or HR, may play a tonic role in inhibiting cardiac vagal baroreflex sensitivity. However, they strongly facilitate the forebrain response to aversive stress, yet reduce the pressor response presumably through greater sympatho-inhibition. These findings outline novel and specific roles for angiotensin II in the CVLM in autonomic regulation.
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Affiliation(s)
- Kesia Palma-Rigo
- Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, 75 Commercial Road, PO Box 6492 St Kilda Road Central, Melbourne, VIC 8008, Australia
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Lim K, Burke SL, Armitage JA, Head GA. Comparison of blood pressure and sympathetic activity of rabbits in their home cage and the laboratory environment. Exp Physiol 2012; 97:1263-71. [PMID: 22613739 DOI: 10.1113/expphysiol.2012.064972] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Methodological improvements in measuring cardiovascular parameters have meant that data can be collected from freely moving animals in their home cage. However, experiments in rabbits still often require them to be restrained in a laboratory setting. The aim of this study was to determine whether measurements collected when rabbits were placed in a holding box in the laboratory are representative of values obtained in freely moving conscious rabbits. Nine New Zealand White rabbits received two radiotelemetry implants to monitor mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA). The MAP measured in the laboratory (71 ± 1 mmHg) was similar to that in the home cage (69 ± 1 mmHg), but there was less MAP variability. The RSNA was also similar in both environments. In contrast, laboratory heart rate (HR) was 7% lower than home cage HR (181 ± 4 beats min(-1), P < 0.001), but HR variability was similar. Baroreflex gain, assessed by spectral analysis, was 19% higher in the laboratory than in the home cage due to lower MAP mid-frequency variability in the laboratory. Home cage circadian patterns of MAP and HR were strongly influenced by feeding and activity. Nevertheless, MAP and RSNA laboratory measurements were the same as average 24 h values and remained similar over several weeks. We conclude that while HR is generally lower in the laboratory, a valid representation of MAP and RSNA can be given by laboratory measurements.
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Affiliation(s)
- Kyungjoon Lim
- Department of Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
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