Requirement of IP₃ receptor 3 (IP₃R3) in nitric oxide induced cardiomyocyte differentiation of mouse embryonic stem cells

Nitric oxide (NO) markedly induces cardiomyocyte (CM) differentiation of embryonic stem (ES) cells. Here we examined the role of the Ca²⁺ signaling in the NO-induced CM differentiation of mouse ES cells. We found that NO induced intracellular Ca²⁺ increases in ES cells in a dose-dependent manner, and application of IP₃ pathway antagonists not only significantly inhibited this induced Ca²⁺ increase but also abolished NO-induced CM differentiation of ES cells. Subsequently, all 3 types of inositol 1, 4, 5-trisphosphate (IP₃) receptors (IP₃Rs) in mouse ES cells were individually or triply knocked down. Interestingly, only knockdown of type 3 IP₃R (IP₃R3) or triple-knockdown of three types of IP₃Rs significantly inhibited the NO-induced Ca²⁺ increases. Consistently, IP₃R3 knockdown blocked the NO-induced CM differentiation of ES cells. CMs derived from IP₃R3 knockdown ES cells also showed both structural and functional defects. In summary, our results indicate that the IP₃R3-Ca²⁺ pathway is required for NO-induced CM differentiation of ES cells. & 2016 Elsevier Inc. All rights reserved.