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Reyes S, Cheng CP, Roberts DJ, Yamashita T, Ahmad S, VonCannon JL, Wright KN, Dell'Italia LJ, Varagic J, Ferrario CM. Angiotensin-(1-12)/chymase axis modulates cardiomyocyte L-type calcium currents in rats expressing human angiotensinogen. Int J Cardiol 2019; 297:104-110. [PMID: 31629566 DOI: 10.1016/j.ijcard.2019.09.052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/18/2019] [Accepted: 09/24/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Activation of the intracrine renin angiotensin systems (RAS) is increasingly recognized as contributing to human pathologies, yet non-canonical renin-independent mechanisms for angiotensin II (Ang II) biosynthesis remain controversial. Direct Ang II generation from angiotensin-(1-12) [Ang-(1-12)] by chymase is an essential intracrine source for regulation of cardiac function. Using a transgenic rat model that overexpresses the human angiotensinogen gene [TGR(hAGT)L1623] and displays increased cardiac Ang II levels, this study aimed to provide evidence for intracrine activation of L-type calcium currents (ICa-L) mediated by the Ang-(1-12)/chymase axis. METHODS AND RESULTS On patch clamp, ICa-L density was significantly higher in TGR(hAGT)L1623 (-6.4 ± 0.3 pA/pF) compared to Sprague Dawley (SD) cardiomyocytes (-4.8, ± 0.5 pA/pF). Intracellular administration of Ang II and Ang-(1-12) elicited a ICa-L increase in both SD and TGR(hAGT)L1623 cardiomyocytes, albeit blunted in transgenic cells. ICa-L activation by intracellular Ang II and Ang-(1-12) was abolished by the specific Ang II type 1 receptor blocker E-3174. Co-administration of a chymase inhibitor prevented activation of ICa-L by Ang-(1-12). Confocal micrographs revealed abundant chymase (mast cell protease 5) immunoreactive protein in SD and TGR(hAGT)L1623 cardiomyocytes. CONCLUSIONS Our data demonstrate the existence in cardiomyocytes of a calcium channel modulatory activity responsive to Ang II generated by the Ang-(1-12)/chymase axis that signals via intracellular receptors. Chronically elevated Ang II in TGR(hAGT)L1623 hearts leading to increased intracellular calcium through ICa-L suggests that activation of this Ang-(1-12)/chymase-governed cardiac intracrine RAS may contribute to the pathological phenotypes observed in the humanized model of chronic hypertension and cardiac hypertrophy.
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Affiliation(s)
- Santiago Reyes
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Che Ping Cheng
- Department of Internal Medicine, Section on Cardiovascular Medicine, Wake Forest School of Medicine, Winston Salem, NC, USA
| | - Drew J Roberts
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Tomohisa Yamashita
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Sarfaraz Ahmad
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Jessica L VonCannon
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Kendra N Wright
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Louis J Dell'Italia
- Birmingham Veteran Affairs Medical Center and Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jasmina Varagic
- Department of Surgery and Cardiovascular Sciences Center, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Carlos M Ferrario
- Departments of Surgery, Physiology and Pharmacology, and Social Sciences, Division of Public Health, Wake Forest School of Medicine, Winston-Salem, NC, USA
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