Blockade of thromboxane A2 signaling attenuates ethanol‐induced myocardial inflammatory response in mice.

Background: Alcohol‐associated cardiomyopathy (ACM) is a cardiac muscle disease characterized by inflammation and oxidative stress. Thromboxane‐prostanoid receptor (TP‐R) plays an important role in the pathogenesis of cardiovascular disease. Herein, we hypothesize that TP‐R mediates alcohol‐induced early cardiac injury. Methods: Eight‐week‐old male C57BL/6 wild‐type mice were fed a chronic ethanol (ET) or control diet (CON) for 10 days followed by a single binge of ethanol or maltose‐dextrin through oral gavage. A cohort of ethanol‐fed mice received SQ 29,548 (SQ), a TP‐R antagonist. RNA sequencing, real‐time PCR, and western blot analysis were performed on left ventricle to investigate alterations in genes and/or proteins mediating oxidative stress, inflammation, and cardiac remodeling. Sirius Red staining was performed to measure myocardial fibrosis. Results: RNA‐sequencing analysis of myocardium from CON and ET groups identified 142 genes that were significantly altered between the two groups. In particular, the gene expression of thioredoxin‐interacting protein (TXNIP), a component of NLR family pyrin domain containing 3 (NLRP3) signaling, which mediates oxidative stress and inflammatory response, was upregulated in response to ethanol exposure. The myocardial protein levels of TP‐R and thromboxane A2 synthase were increased upon alcohol exposure. Ethanol increased the levels of 4‐hydroxynonenal, a marker of oxidative stress, with a concomitant increase in the protein levels of TXNIP and NLRP3, and administration of SQ attenuated these effects. Additionally, ethanol increased the protein levels of pro‐inflammatory mediators, including tumor necrosis factor alpha and the NLRP3 downstream product, secretory interleukin 1 beta, and SQ blunted these effects. Finally, the Sirius red staining of the myocardium revealed an increase in collagen deposition in ethanol‐fed mice which was attenuated by TP‐R antagonism. Conclusion: This study demonstrates that ethanol promotes the NLRP3 signaling pathway within the myocardium, leading to a pro‐inflammatory milieu that potentially initiates early myocardial remodeling, and TP‐R antagonism attenuates this effect. [ABSTRACT FROM AUTHOR]