Metoprolol disrupts inflammatory response of human cardiomyocytes via β-arrestin2 biased agonism and NF-κB signaling modulation

Aims: Recent evidence supports non-class cardioprotective effects of metoprolol against neutrophil-mediated ischemia-reperfusion injury during exacerbated inflammation. Whether metoprolol exerts direct antiinflammatory effect on cardiomyocytes is unknown. Accordingly, we aimed to investigate the direct antiinflammatory effects of metoprolol in a cellular model of human induced pluripotent stem cell-derived cardiomyocytes (hiCMs) and to explore the role of β-arrestin2 (β-ARR2) biased agonism signaling pathway. Methods and results: hiCMs were treated with TNF-α for 24 h, followed by 4-hour treatment with metoprolol or esmolol. Electrical response of hiCMs to β1-selective blockade was assessed by microelectrode arrays technology. The effect on inflammatory and adhesion molecule expression was evaluated in wild-type and β-ARR2 silenced hiCMs. To silence β-ARR2 expression, hiCMs were transfected with a specific small interfering RNA targeting β-ARR2 mRNA and preventing its translation. TNF-α stimulation boosted the expression of IκB, NF-κB, IL1β, IL6, and VCAM1 in hiCMs. TNF-α-treated hiCMs showed similar physiological responses to metoprolol and esmolol, with no difference in field potential duration and beat period recorded. Adding metoprolol significantly decreased inflammatory response patterns in wildtype hiCMs by dampening TNF-α induced expression of NF-κB, IL1β, and IL6, but not in β-ARR2-knockout hiCMs. A similar response was not observed in presence of β1-selective blockade with esmolol. Conclusions: Metoprolol exerts a non-class direct anti-inflammatory effect on hi-CMs. β1-selective blockade with metoprolol disrupts inflammatory responses induced by TNF-α and induces significant inhibition of NF-κB signaling cascade via β-ARR2 biased agonism. If confirmed at clinical level, metoprolol could be tested and repurposed to treat cardiac inflammatory disorders.