Phosphoproteomic response underpinning cardiac organoid maturation by electronic pacing and directed maturation media

Cardiac maturation is an important developmental phase where there are profound biological and functional changes after birth in mammals. Herein, we use our profiling of human heart maturation in vivo to identify key drivers of maturation in our human cardiac organoid (hCO) model. After screening of various metabolism modulating factors, we established a directed maturation protocol to induce mature cardiac expression. We next compared directed maturation treatment to electrical pacing using phosphoproteomics in order to assess the similarities in the induction of maturation. The electrical pacing protocol utilized a custom platform, where we added Heart-Dyno inserts into C-pace system in 24-well plates enabling 120 bpm pacing for 5 minutes without causing toxicity. In this dataset, we compared 3 replicates of CTRL (our original serum free organoid protocol), electrical pacing (the standard protocol for maturation of cardiac stem cells), and directed maturation protocol (DM, new protocol) through phosphoproteomics.