Cytokinetics, Inc., 350 Oyster Point Boulevard, South San Francisco, California 94080, United States.
J Med Chem. 2024 May 23;67(10):7859-7869. doi: 10.1021/acs.jmedchem.3c02412. Epub 2024 Mar 7.
Novel cardiac troponin activators were identified using a high throughput cardiac myofibril ATPase assay and confirmed using a series of biochemical and biophysical assays. HTS hit increased rat cardiomyocyte fractional shortening without increasing intracellular calcium concentrations, and the biological target of and was determined to be the cardiac thin filament. Subsequent optimization to increase solubility and remove PDE-3 inhibition led to the discovery of and enabled pharmacological evaluation of cardiac troponin activation without the competing effects of PDE-3 inhibition. Rat echocardiography studies using demonstrated concentration-dependent increases in cardiac fractional shortening up to 95%. Isothermal calorimetry studies confirmed a direct interaction between and a cardiac troponin chimera with a dissociation constant of 11.5 ± 3.2 μM. These results provide evidence that direct activation of cardiac troponin without the confounding effects of PDE-3 inhibition may provide benefit for patients with cardiovascular conditions where contractility is reduced.
新型心肌肌钙蛋白激活剂是通过高通量心肌纤维丝 ATP 酶检测法筛选发现的，并通过一系列生化和生物物理检测法进行了验证。高通量筛选得到的化合物 HTS hit 可增加大鼠心肌细胞的分数缩短率，而不增加细胞内钙离子浓度，且化合物 和 的生物靶标被确定为心肌细肌丝。随后的优化旨在提高化合物的水溶性并消除 PDE-3 抑制作用，从而发现了化合物 ，并实现了心肌肌钙蛋白激活的药理学评价，而不会受到 PDE-3 抑制作用的竞争影响。使用 进行的大鼠超声心动图研究表明，药物浓度依赖性地增加了心脏分数缩短率，最高可达 95%。等温量热法研究证实了化合物 与心肌肌钙蛋白嵌合体之间的直接相互作用，其解离常数为 11.5 ± 3.2 μM。这些结果提供了证据表明，直接激活心肌肌钙蛋白而不受 PDE-3 抑制作用的干扰，可能为心血管状况导致收缩力降低的患者带来益处。
