Cardiomyocyte‐Specific Snrk Prevents Inflammation in the Heart

• Published in: Journal of the American Heart Association Vol. 8; no. 22; p. e012792
• Main Authors: Thirugnanam, Karthikeyan, Cossette, Stephanie M., Lu, Qiulun, Chowdhury, Shreya R., Harmann, Leanne M., Gupta, Ankan, Spearman, Andrew D., Sonin, Dmitry L., Bordas, Michelle, Kumar, Suresh N., Pan, Amy Y., Simpson, Pippa M., Strande, Jennifer L., Bishop, Erin, Zou, Ming‐Hui, Ramchandran, Ramani
• Format: Journal Article
• Language: English
• Published: England John Wiley and Sons Inc 19.11.2019; Wiley
• Subjects: Angiotensin II - pharmacology; Animals; cardiac hypertrophy; cardiomyocyte; Cell Line; endothelial cell; Endothelial Cells - metabolism; fibrosis; Fibrosis - genetics; Fibrosis - metabolism; Fibrosis - pathology; Heart - drug effects; heart failure; Heart Failure - genetics; Heart Failure - metabolism; Heart Failure - pathology; In Vitro Techniques; inflammation; Inflammation - genetics; Inflammation - metabolism; Inflammation - pathology; Macrophages - metabolism; Macrophages - pathology; Mice; Mice, Knockout; Myocardium - metabolism; Myocardium - pathology; Myocytes, Cardiac - metabolism; NF-kappa B - metabolism; Original Research; Protein Serine-Threonine Kinases - genetics; Vasoconstrictor Agents - pharmacology; Ventricular Dysfunction, Left; heart failure; inflammation; endothelial cell; cardiomyocyte; fibrosis; NF‐kB; cardiac hypertrophy
• ISSN: 2047-9980; 2047-9980
• DOI: 10.1161/JAHA.119.012792

Background The SNRK (sucrose-nonfermenting-related kinase) enzyme is critical for cardiac function. However, the underlying cause for heart failure observed in cardiac conditional knockout mouse is unknown. Methods and Results Previously, 6-month adult mice knocked out for in cardiomyocytes (CMs) displayed left ventricular dysfunction. Here, 4-month adult mice, on angiotensin II (Ang II) infusion, show rapid decline in cardiac systolic function, which leads to heart failure and death in 2 weeks. These mice showed increased expression of nuclear factor κ light chain enhancer of activated B cells (NF-κB), inflammatory signaling proteins, proinflammatory proteins in the heart, and fibrosis. Interestingly, under Ang II infusion, mice knocked out for in endothelial cells did not show significant systolic or diastolic dysfunction. Although an NF-κB inflammation signaling pathway was increased in knockout endothelial cells, this did not lead to fibrosis or mortality. In hearts of adult mice knocked out for in CMs, we also observed NF-κB pathway activation in CMs, and an increased presence of Mac2 macrophages was observed in basal and Ang II-infused states. In vitro analysis of knockdown HL-1 CMs revealed similar upregulation of the NF-κB signaling proteins and proinflammatory proteins that was exacerbated on Ang II treatment. The Ang II-induced NF-κB pathway-mediated proinflammatory effects were mediated in part through protein kinase B or AKT, wherein AKT inhibition restored the proinflammatory signaling protein levels to baseline in knockdown HL-1 CMs. Conclusions During heart failure, SNRK acts as a cardiomyocyte-specific repressor of cardiac inflammation and fibrosis.