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Forrester EA, Benítez-Angeles M, Redford KE, Rosenbaum T, Abbott GW, Barrese V, Dora K, Albert AP, Dannesboe J, Salles-Crawley I, Jepps TA, Greenwood IA. Crucial role for Sodium Hydrogen Exchangers in SGLT2 inhibitor-induced arterial relaxations. bioRxiv 2023:2023.12.05.570303. [PMID: 38116028 PMCID: PMC10729745 DOI: 10.1101/2023.12.05.570303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Introduction Sodium dependent glucose transporter 2 (SGLT2 or SLC5A2) inhibitors effectively lower blood glucose and are also approved treatments for heart failure independent of raised glucose. One component of the cardioprotective effect is reduced cardiac afterload but the mechanisms underlying peripheral relaxation are ill defined and variable. We speculated that SGLT2 inhibitors promoted arterial relaxation via the release of the potent vasodilator calcitonin gene-related peptide (CGRP) from sensory nerves independent of glucose transport. Experimental approach The functional effects of SGLT2 inhibitors (dapagliflozin, empagliflozin, ertugliflozin) and the sodium/hydrogen exchanger 1 (NHE1) blocker cariporide were determined on pre-contracted mesenteric and renal arteries from male Wistar rats using Wire-Myography. SGLT2, NHE1, CGRP and TRPV1 expression in both arteries was determined by Western blot and immunohistochemistry. Kv7.4/5/KCNE4 and TRPV1 currents were measured in the presence and absence of dapagliflozin and empagliflozin. Results All SGLT2 inhibitors produced a concentration dependent relaxation (1µM-100µM) of mesenteric arteries that was considerably greater than in renal arteries. Cariporide relaxed mesenteric arteries but not renal arteries. Immunohistochemistry with TRPV1 and CGRP antibodies revealed a dense innervation of sensory nerves in mesenteric arteries that was absent in renal arteries. Consistent with a greater sensory nerve component, the TRPV1 agonist capsaicin produced significantly greater relaxations in mesenteric arteries compared to renal arteries. Relaxations to dapagliflozin, empagliflozin and cariporide were attenuated by incubation with the CGRP receptor antagonist BIBN-4096, the Kv7 blocker linopirdine and the TRPV1 antagonist AMG-517 as well as by depletion of neuronal CGRP. Neither dapagliflozin nor empagliflozin directly activated heterologously expressed TRPV1 channels or Kv7 channels. Strikingly, only NHE1 colocalised with TRPV1 in sensory nerves, and cariporide pre-application prevented the relaxant response to SGLT2 inhibitors. Conclusions SGLT2 inhibitors relax mesenteric arteries by a novel mechanism involving the release of CGRP from sensory nerves following inhibition of the Na + /H + exchanger.
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Lin J, Scullion L, Garland CJ, Dora K. Gβγ subunit signalling underlies neuropeptide Y-stimulated vasoconstriction in rat mesenteric and coronary arteries. Br J Pharmacol 2023; 180:3045-3058. [PMID: 37460913 PMCID: PMC10953346 DOI: 10.1111/bph.16192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/27/2023] [Accepted: 07/09/2023] [Indexed: 08/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Raised serum concentrations of the sympathetic co-transmitter neuropeptide Y (NPY) are linked to cardiovascular diseases. However, the signalling mechanism for vascular smooth muscle (VSM) constriction to NPY is poorly understood. Therefore, the present study investigated the mechanisms of NPY-induced vasoconstriction in rat small mesenteric (RMA) and coronary (RCA) arteries. EXPERIMENTAL APPROACH Third-order mesenteric or intra-septal arteries from male Wistar rats were assessed in wire myographs for isometric tension, VSM membrane potential and VSM intracellular Ca2+ events. KEY RESULTS NPY stimulated concentration-dependent vasoconstriction in both RMA and RCA, which was augmented by blocking NO synthase or endothelial denudation in RMA. NPY-mediated vasoconstriction was blocked by the selective Y1 receptor antagonist BIBO 3304 and Y1 receptor protein expression was detected in both the VSM and endothelial cells in RMA and RCA. The selective Gβγ subunit inhibitor gallein and the PLC inhibitor U-73122 attenuated NPY-induced vasoconstriction. Signalling via the Gβγ-PLC pathway stimulated VSM Ca2+ waves and whole-field synchronised Ca2+ flashes in RMA and increased the frequency of Ca2+ flashes in myogenically active RCA. Furthermore, in RMA, the Gβγ pathway linked NPY to VSM depolarization and generation of action potential-like spikes associated with intense vasoconstriction. This depolarization activated L-type voltage-gated Ca2+ channels, as nifedipine abolished NPY-mediated vasoconstriction. CONCLUSIONS AND IMPLICATIONS These data suggest that the Gβγ subunit, which dissociates upon Y1 receptor activation, initiates VSM membrane depolarization and Ca2+ mobilisation to cause vasoconstriction. This model may help explain the development of microvascular vasospasm during raised sympathetic nerve activity.
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Affiliation(s)
- JinHeng Lin
- Department of PharmacologyUniversity of OxfordOxfordUK
| | | | | | - Kim Dora
- Department of PharmacologyUniversity of OxfordOxfordUK
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Herring N, Tapoulal N, Kalla M, Ye X, Borysova L, Lee R, Dall'Armellina E, Stanley C, Ascione R, Lu CJ, Banning AP, Choudhury RP, Neubauer S, Dora K, Kharbanda RK, Channon KM. Neuropeptide-Y causes coronary microvascular constriction and is associated with reduced ejection fraction following ST-elevation myocardial infarction. Eur Heart J 2020; 40:1920-1929. [PMID: 30859228 PMCID: PMC6588241 DOI: 10.1093/eurheartj/ehz115] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/23/2018] [Accepted: 02/18/2019] [Indexed: 12/11/2022] Open
Abstract
Aims The co-transmitter neuropeptide-Y (NPY) is released during high sympathetic drive, including ST-elevation myocardial infarction (STEMI), and can be a potent vasoconstrictor. We hypothesized that myocardial NPY levels correlate with reperfusion and subsequent recovery following primary percutaneous coronary intervention (PPCI), and sought to determine if and how NPY constricts the coronary microvasculature. Methods and results Peripheral venous NPY levels were significantly higher in patients with STEMI (n = 45) compared to acute coronary syndromes/stable angina ( n = 48) or with normal coronary arteries (NC, n = 16). Overall coronary sinus (CS) and peripheral venous NPY levels were significantly positively correlated (r = 0.79). STEMI patients with the highest CS NPY levels had significantly lower coronary flow reserve, and higher index of microvascular resistance measured with a coronary flow wire. After 2 days they also had significantly higher levels of myocardial oedema and microvascular obstruction on cardiac magnetic resonance imaging, and significantly lower ejection fractions and ventricular dilatation 6 months later. NPY (100–250 nM) caused significant vasoconstriction of rat microvascular coronary arteries via increasing vascular smooth muscle calcium waves, and also significantly increased coronary vascular resistance and infarct size in Langendorff hearts. These effects were blocked by the Y1 receptor antagonist BIBO3304 (1 μM). Immunohistochemistry of the human coronary microvasculature demonstrated the presence of vascular smooth muscle Y1 receptors. Conclusion High CS NPY levels immediately after reperfusion correlate with microvascular dysfunction, greater myocardial injury, and reduced ejection fraction 6 months after STEMI. NPY constricts the coronary microcirculation via the Y1 receptor, and antagonists may be a useful PPCI adjunct therapy. ![]()
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Affiliation(s)
- Neil Herring
- Department of Physiology, Anatomy and Genetics, Burdon Sandersn Cardiac Science Centre, University of Oxford, Parks Road, Oxford OX13PT, UK.,Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK
| | - Nidi Tapoulal
- Department of Physiology, Anatomy and Genetics, Burdon Sandersn Cardiac Science Centre, University of Oxford, Parks Road, Oxford OX13PT, UK
| | - Manish Kalla
- Department of Physiology, Anatomy and Genetics, Burdon Sandersn Cardiac Science Centre, University of Oxford, Parks Road, Oxford OX13PT, UK.,Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK
| | - Xi Ye
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford UK
| | - Lyudmyla Borysova
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford UK
| | - Regent Lee
- Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK
| | - Erica Dall'Armellina
- Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK.,Oxford Acute Vascular Imaging Centre, Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford UK
| | | | - Raimondo Ascione
- Bristol Heart Institute, Bristol Royal Infirmary, and Faculty of Health Sciences, University of Bristol, Horfield Road, Bristol UK
| | - Chieh-Ju Lu
- Department of Physiology, Anatomy and Genetics, Burdon Sandersn Cardiac Science Centre, University of Oxford, Parks Road, Oxford OX13PT, UK
| | - Adrian P Banning
- Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way Oxford, UK
| | - Robin P Choudhury
- Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK.,Oxford Acute Vascular Imaging Centre, Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford UK
| | - Stefan Neubauer
- Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way Oxford, UK
| | - Kim Dora
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford UK
| | - Rajesh K Kharbanda
- Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way Oxford, UK
| | - Keith M Channon
- Department of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way Oxford, UK
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Beleznai T, Takano H, Hamill C, Yarova P, Douglas G, Channon K, Dora K. Enhanced K(+)-channel-mediated endothelium-dependent local and conducted dilation of small mesenteric arteries from ApoE(-/-) mice. Cardiovasc Res 2011; 92:199-208. [PMID: 21690174 DOI: 10.1093/cvr/cvr181] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Agonists that evoke smooth muscle cell hyperpolarization have the potential to stimulate both local and conducted dilation. We investigated whether the endothelium-dependent vasodilators acetylcholine (ACh) and SLIGRL stimulated conducted dilation and whether this was altered by deficiency in apolipoprotein E (ApoE(-/-)). METHODS AND RESULTS Isolated mesenteric arteries were cannulated, pressurized, and precontracted with phenylephrine. Agonists were either added to the bath to study local dilation or were restricted to one end of arteries to study conducted dilation. An enhanced sensitivity to both ACh and SLIGRL was observed in mesenteric arteries from ApoE(-/-) mice compared with wild-type controls. Inhibition of nitric oxide (NO) synthase blocked ACh responses, but had no effect on maximum dilation to SLIGRL. SLIGRL increased endothelial cell Ca(2+), hyperpolarized smooth muscle cells, and fully dilated arteries. The NO-independent dilation to SLIGRL was blocked with high [KCl] or Ca(2+)-activated K(+)-channel blockers. The hyperpolarization and dilation to SLIGRL passed through the artery to at least 2.5 mm upstream. The conducted dilation was not affected by a deficit in ApoE and could also be stimulated by ACh, suggesting NO itself could stimulate conducted dilation. CONCLUSION In small mesenteric arteries of ApoE(-/-) mice, NO-independent dilation is enhanced. Since both NO-dependent and -independent pathways can stimulate local and conducted dilation, the potential for reducing vascular resistance is improved in these vessels.
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Affiliation(s)
- Timea Beleznai
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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