RYR1 and cyclic hematopoiesis: Importantly, CH-induced increase in the ratio of RyR-mediated SR Ca2+ leak to SR Ca2+ storage was fully eliminated in PASMCs from RyR2−/− mice relative to WT (control) animals (5.3 ± 1.6% vs 6.5 ± 1.5%), suggesting RyR2 KO was sufficient to reverse the abnormal SR leak in PASMCs from CH mice (Fig. 1e).