Lindsey McGurran

Using radioligand binding assays, I determined the functional effect of high-throughput screening (HTS) detected compounds on RyR activity. Calcium regulation through the RyR calcium release channel is vital to proper muscle function. During normal excitation-contraction (EC) coupling, RyR1 in skeletal muscle tissue and RyR2 in cardiac muscle tissue releases Ca2+ from the sarcoplasmic reticulum (SR). However excessive Ca2+ release through RyR at rest is central to many skeletal and cardiac muscle conditions, including muscular dystrophy, arrhythmias and heart failure. This leaky state is an important target for therapeutic development. The FRET-based HTS platform identifies compounds (hits) that allosterically inhibit the Ca2+ leak during rest by altering binding of key RyR regulators: FKBP and CaM, but that have minimal effects under contracting conditions. To determine the functional effect of the identified hit compounds, I used [3H]ryanodine binding assays to evaluate the functional impact of 29 promising hit compounds. Eight hits of therapeutic potential were identified, reducing activity of RyR1 and/or RyR2, and we advanced with testing the functional effect of several compound analogues. Overall, we found several promising compounds for further testing on SR Ca2+ leak and contractility of patient derived skeletal muscle fibers and cardiac myocytes. These indicated compounds have the future potential to be used as an effective therapy for skeletal and cardiac myopathies as a modulator of RyR1 and/or RyR2.