Human embryonic stem cell–derived cardiomyocytes can mobilize 1,4,5‐inositol trisphosphate–operated [Ca²⁺]_i stores

Abstract

Because previous findings showed that in human embryonic stem cell-derived cardiomyocytes (hESC-CM) the machinery for Ca2+-induced release of calcium is immature, we tested the hypothesis that hESC-CM contain functional 1,4,5-inositol triphosphate (IP3)-operated intracellular Ca2+ ([Ca2+]i) stores. We investigated the effects of angiotensin II (AT-II) and endothelin 1 (ET-1), which activate the 1,4,5-IP3 pathway, on [Ca2+]i transients and contractions in hESC-CM. Our major findings were that in hESC-CM, both AT-II (10(-9)-10(-7) M) and ET-1 (10(-9)-10(-7) M) exert inotropic and lusitropic effects. The involvement of 1,4,5-IP3-dependent intracellular Ca2+ release in AT-I-induced effects was supported by these findings: the effects of AT-II were blocked by 2-aminoethoxyphenyl borate (2-APB, a 1,4,5-IP3 receptor blocker) and U73122 (a phosopholipase C blocker); and hESC-CM express AT-II type 1 and IP3 type I and II receptors as determined by fluorescence immunostaining. In conclusion, hESC-CM exhibit functional AT-II and ET-1 signaling pathways, as well as 1,4,5-IP3-operated releasable Ca2+ stores.

Electrophysiological properties and calcium handling of embryonic stem cell-derived cardiomyocytes

“…Ca 2+ sparks were also identified by confocal Ca 2+ imaging 45, 46, 47. The involvement of IP 3 -dependent Ca 2+ release in intracellular Ca 2+ transient was demonstrated in human ESC-CMs by using angiotensin II (AT-II) and endothelin 1 (ET-1), which activate the IP 3 R-mediated Ca 2+ release 48 . As Ca 2+ exclusion pathways, SERCA2 and NCX were expressed at levels comparable to those of the adult porcine myocardium.…”

Electrophysiological and contractile function of cardiomyocytes derived from human embryonic stem cells

“…Many studies of hESC-CMs have demonstrated varying degrees of structural and contractile organization -- in particular the presence of cross-striations, as well as the contractile proteins troponin, myosin heavy chain, tropomyosin, and α-actinin (Binah et al, 2007; Boudou et al, 2011; Caspi et al, 2007a; Dolnikov et al, 2005; Fu et al, 2010; Habeler et al, 2009; Kehat et al, 2001; Kim et al, 2010; Liu et al, 2007; Mummery et al, 2003; Otsuji et al, 2010; Pekkanen-Mattila et al, 2009; Schaaf et al, 2011; Sedan et al, 2010; Sedan et al, 2008). Additionally, mechanical contraction has been measured in both hEBs (Binah et al, 2007; Brito-Martins et al, 2008; Pillekamp et al, 2009; Pillekamp et al, 2007; Schaaf et al, 2011; Sedan et al, 2010; Sedan et al, 2008) and isolated hESC-CMs (Abdul Kadir et al, 2009; Germanguz et al, 2011).…”

“…Additionally, mechanical contraction has been measured in both hEBs (Binah et al, 2007; Brito-Martins et al, 2008; Pillekamp et al, 2009; Pillekamp et al, 2007; Schaaf et al, 2011; Sedan et al, 2010; Sedan et al, 2008) and isolated hESC-CMs (Abdul Kadir et al, 2009; Germanguz et al, 2011). Contraction of hEBs increased with an increase in extracellular calcium concentration (Pillekamp et al, 2009; Schaaf et al, 2011), addition of isoproterenol (Brito-Martins et al, 2008; Schaaf et al, 2011), addition of adrenaline (Apati et al, 2012) and IP3R activation (Sedan et al, 2010; Sedan et al, 2008). Consistent with the findings of immature or absent calcium cycling described in the next section, agents that block RyR release or SERCA uptake had no effect on contraction amplitude in hEBs (Binah et al, 2007; Dolnikov et al, 2005; Dolnikov et al, 2006).…”

Present state and future perspectives of using pluripotent stem cells in toxicology research

“…As observed in foetal cardiomyocytes, hESC-derived cardiomyocytes exhibited the I f channel and showed a low V max . Moreover, immaturity of intracellular Ca 2+ handling of hESC-derived cardiomyocytes was reported, although to a different extent (Dolnikov et al 2006; Liu et al 2007; Satin et al 2008; Zhu et al 2009; Sedan et al 2010). …”