Cardiac Troponin Activator Increases Cardiac Contractility in Rats.

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.

Discovery of Reldesemtiv, a Fast Skeletal Muscle Troponin Activator for the Treatment of Impaired Muscle Function.

The discovery of reldesemtiv, a second-generation fast skeletal muscle troponin activator (FSTA) that increases force production at submaximal stimulation frequencies, is reported. Property-based optimization of high throughput screening hit led to compounds with improved free exposure and muscle activation potency compared to the first-generation FSTA, tirasemtiv. Reldesemtiv demonstrated increased muscle force generation in a phase 1 clinical trial and is currently being evaluated in clinical trials for the treatment of amyotrophic lateral sclerosis.

Assessment of Intra- and Inter-observer Measurement Variability in a Radiographic Metacarpophalangeal Joint Osteophytosis Scoring System for the Horse.

The study evaluated the intra- and inter-observer measurement variability of an osteophytosis metacarpophalangeal joint scoring system. Ten () dorso/palmar, latero/medial, and oblique views of equine metacarpophalangeal joints affected by osteoarthritis were examined. Nine assessment points were graded (scale: 0-3) twice by five veterinary students (inexperienced group, I) and four equine veterinary surgeons (expert group, E).

Discovery of , the First Direct Fast Skeletal Muscle Troponin Activator.

The identification and optimization of the first activators of fast skeletal muscle are reported. Compound was identified from high-throughput screening (HTS) and subsequently found to improve muscle function via interaction with the troponin complex. Optimization of for potency, metabolic stability, and physical properties led to the discovery of tirasemtiv (), which has been extensively characterized in clinical trials for the treatment of amyotrophic lateral sclerosis.

Activation of fast skeletal muscle troponin as a potential therapeutic approach for treating neuromuscular diseases.

Limited neural input results in muscle weakness in neuromuscular disease because of a reduction in the density of muscle innervation, the rate of neuromuscular junction activation or the efficiency of synaptic transmission. We developed a small-molecule fast-skeletal-troponin activator, CK-2017357, as a means to increase muscle strength by amplifying the response of muscle when neural input is otherwise diminished secondary to neuromuscular disease. Binding selectively to the fast-skeletal-troponin complex, CK-2017357 slows the rate of calcium release from troponin C and sensitizes muscle to calcium.