Abstract 13500: An Improved Reporter Identifies Ruxolitinib as a Potent and Cardioprotective CaMKII Inhibitor

• Published in: Circulation (New York, N.Y.) N.Y.), 2023-11, Vol.148 (Suppl_1)
• Main Authors: Reyes Gaido, Oscar E, Pavlaki, Nikoleta, Granger, Jonathan, Mesubi, Olurotimi O, Liu, Bian, Lin, Brian L, Long, Alan, Walker, David, Mayourian, Joshua, Schole, Kate L, Terrillion, Chantelle E, Nkashama, Lubika J, Hulsurkar, Mohit M, Dorn, Lauren E, Ferrero, Kimberly M, Huganir, Richard L, Muller, Frank U, Wehrens, Xander H, Liu, Jun O, Luczak, Elizabeth, Bezzerides, Vassilios J, Anderson, Mark E
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.148.suppl_1.13500

Abstract only Background: Ca 2+ /Calmodulin-dependent protein kinase II (CaMKII) hyperactivity is an established driver of cardiac arrhythmias. Despite proven benefits of CaMKII inhibition in numerous preclinical arrhythmia models, translation of CaMKII antagonists into humans has remained unsuccessful, and today, there are no clinically approved CaMKII inhibitors. Our ability to identify potent CaMKII inhibitors has been hamstrung by a lack of a CaMKII biosensor with sufficient sensitivity for high throughput drug discovery. Research question: We hypothesized that development of a CaMKII biosensor with high throughput capabilities would enable identification of CaMKII inhibitors capable of preventing arrhythmias. Methods: To address this problem, we engineered and validated a new genetically encoded CaMKII biosensor: CaMKAR (CaMKII Activity Reporter). CaMKAR enjoys a dynamic range of 227 ± 11.1 %, seconds-scale kinetics, robust specificity, and dual in cellulo and in vitro functionality. This makes CaMKAR the fastest and most sensitive CaMKII biosensor to date and the first that is amenable for in cellulo drug screening. Results: Using CaMKAR, we carried out a drug repurposing screen (4,475 compounds in clinical use) in human cells. This yielded five previously unrecognized CaMKII inhibitors: ruxolitinib, baricitinib, silmitasertib, crenolanib, and abemaciclib (false discovery-adjusted p