| First Author | Thirugnanam K | Year | 2019 |
| Journal | J Am Heart Assoc | Volume | 8 |
| Issue | 22 | Pages | e012792 |
| PubMed ID | 31718444 | Mgi Jnum | J:299149 |
| Mgi Id | MGI:6490721 | Doi | 10.1161/JAHA.119.012792 |
| Citation | Thirugnanam K, et al. (2019) Cardiomyocyte-Specific Snrk Prevents Inflammation in the Heart. J Am Heart Assoc 8(22):e012792 |
| abstractText | Background The SNRK (sucrose-nonfermenting-related kinase) enzyme is critical for cardiac function. However, the underlying cause for heart failure observed in Snrk cardiac conditional knockout mouse is unknown. Methods and Results Previously, 6-month adult mice knocked out for Snrk 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 kappa light chain enhancer of activated B cells (NF-kappaB), inflammatory signaling proteins, proinflammatory proteins in the heart, and fibrosis. Interestingly, under Ang II infusion, mice knocked out for Snrk in endothelial cells did not show significant systolic or diastolic dysfunction. Although an NF-kappaB inflammation signaling pathway was increased in Snrk knockout endothelial cells, this did not lead to fibrosis or mortality. In hearts of adult mice knocked out for Snrk in CMs, we also observed NF-kappaB pathway activation in CMs, and an increased presence of Mac2(+) macrophages was observed in basal and Ang II-infused states. In vitro analysis of Snrk knockdown HL-1 CMs revealed similar upregulation of the NF-kappaB signaling proteins and proinflammatory proteins that was exacerbated on Ang II treatment. The Ang II-induced NF-kappaB 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 Snrk knockdown HL-1 CMs. Conclusions During heart failure, SNRK acts as a cardiomyocyte-specific repressor of cardiac inflammation and fibrosis. |
