OptoRyR2

In cardiomyocytes, the ryanodine receptor type 2 (RyR2) gates Ca²⁺ release from sarco/endoplasmic reticulum (ER/SR) by the Ca²⁺-induced Ca²⁺ release mechanism. Pathological Ca²⁺ leak through RyR2 can initiate lethal cardiac arrhythmias but a cellular model for screening of RyR2-modulators is lacking due to the challenge to experimentally trigger RyR2 by cytosolic Ca²⁺. In this project we employed optogenetics to induce cytosolic Ca²⁺ elevation close to the RyR2 for triggering its opening and Ca²⁺ release from the ER/SR. Therefore, the novel protein OptoRyR2 was developed by fusion of a light-gated Ca²⁺-permeable Channelrhodopsin-2 variant (CatChUP) with EYFP and a 157 Å linker to the N-terminus of human RyR2. Activation of the CatChUP part in OptoRyR2 by light leads to Ca²⁺ release from the SR/ER into the cytosol, which in turn triggers RyR2 opening. Because Ca²⁺ is the physiological trigger to activate RyR2, we propose that OptoRyR2 is an important novel tool for high content screening of potential RyR2 modulating substances.

Patent applied EP3932940A1