Cardiomyocyte-Specific Deletion of Orai1 Reveals Its Protective Role in Angiotensin-II-Induced Pathological Cardiac Remodeling

• Published in: Cells (Basel, Switzerland) Vol. 9; no. 5; p. 1092
• Main Authors: Segin, Sebastian, Berlin, Michael, Richter, Christin, Flockerzi, Rebekka Medert Veit, Worley, Paul, Freichel, Marc, Londoño, Juan E Camacho
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28.04.2020; MDPI
• Subjects: Angiotensin; Angiotensin II; Angiotensin II - metabolism; Angiotensins - metabolism; Animals; Calcineurin; calcium; Calcium - metabolism; Calcium channels; Calcium Signaling; Calcium signalling; cardiac function; cardiac remodeling; Cardiomyocytes; Carrier Proteins - metabolism; Catheters; Embryogenesis; Experiments; Female; Fibrosis; Gene expression; Heart; Heart failure; Hypertrophy; Kinases; Lethality; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microfilament Proteins - metabolism; Muscle contraction; Muscle Proteins - metabolism; Mutation; Myocardium; Myocardium - metabolism; Myocytes, Cardiac - metabolism; Myocytes, Cardiac - physiology; Neonates; neurohumoral stimulus; NF-AT protein; Orai1 protein; ORAI1 Protein - genetics; ORAI1 Protein - metabolism; ORAI1 Protein - physiology; Orai1 proteins; Ostomy; Proteins; Rodents; Signal transduction; Stem cells; STIM1 protein; Stromal Interaction Molecule 1 - metabolism; Ventricular Remodeling - genetics; Ventricular Remodeling - physiology; United Kingdom > UK; United States > US; Germany; cardiac function; Orai1 proteins; calcium; neurohumoral stimulus; cardiac remodeling
• ISSN: 2073-4409; 2073-4409
• DOI: 10.3390/cells9051092

Pathological cardiac remodeling correlates with chronic neurohumoral stimulation and abnormal Ca signaling in cardiomyocytes. Store-operated calcium entry (SOCE) has been described in adult and neonatal murine cardiomyocytes, and Orai1 proteins act as crucial ion-conducting constituents of this calcium entry pathway that can be engaged not only by passive Ca store depletion but also by neurohumoral stimuli such as angiotensin-II. In this study, we, therefore, analyzed the consequences of Orai1 deletion for cardiomyocyte hypertrophy in neonatal and adult cardiomyocytes as well as for other features of pathological cardiac remodeling including cardiac contractile function in vivo. Cellular hypertrophy induced by angiotensin-II in embryonic cardiomyocytes from Orai1-deficient mice was blunted in comparison to cells from litter-matched control mice. Due to lethality of mice with ubiquitous Orai1 deficiency and to selectively analyze the role of Orai1 in adult cardiomyocytes, we generated a cardiomyocyte-specific and temporally inducible Orai1 knockout mouse line (Orai1 ). Analysis of cardiac contractility by pressure-volume loops under basal conditions and of cardiac histology did not reveal differences between Orai1 mice and controls. Moreover, deletion of Orai1 in cardiomyocytes in adult mice did not protect them from angiotensin-II-induced cardiac remodeling, but cardiomyocyte cross-sectional area and cardiac fibrosis were enhanced. These alterations in the absence of Orai1 go along with blunted angiotensin-II-induced upregulation of the expression of Myoz2 and a lack of rise in angiotensin-II-induced STIM1 and Orai3 expression. In contrast to embryonic cardiomyocytes, where Orai1 contributes to the development of cellular hypertrophy, the results obtained from deletion of Orai1 in the adult myocardium reveal a protective function of Orai1 against the development of angiotensin-II-induced cardiac remodeling, possibly involving signaling via Orai3/STIM1-calcineurin-NFAT related pathways.