KR-31466, a Benzopyranylindol Analog, Attenuates Hypoxic Injury Through Mitochondrial KATP Channel and Protein Kinase C Activation in Heart-Derived H9c2 Cells

Abstract

Abstract. In the present study, we investigated whether a novel benzopyranylindol analogue, KR-31466 (KR466) (1-[(2S,3R,4S)-3,4-dihydro-2-dimethoxymethyl-3-hydroxy-2-methyl-6-nitro-2H-1-benzopyran-4-yl]-1H-indole-2-carboxylic acid ethyl ester) can attenuate hypoxic injury in heart-derived H9c2 cells and, if so, whether the protective effect of KR466 is mediated through mitochondrial ATP-sensitive potassium (mtK ATP ) opening. The treatment of H9c2 cells with KR466 (3 -30 mM) significantly reduced hypoxia-induced cell death in a concentration-dependent manner, as shown by lactate dehydrogenase release and propidium iodide-uptake. In addition, KR466 (10 mM) significantly reduced the increase in hypoxia-induced TUNEL-positive cells, suggesting its anti-apoptotic potential in H9c2 cells. The protective effects of KR466 were abolished by 5-hydroxydecanoate, a specific blocker of the mtK ATP channel, suggesting the involvement of the mtK ATP channel in the protective effect of KR466. A specific inhibitor of protein kinase C (PKC), chelerythrine (3 m M), significantly attenuated the protective effect of KR466 against hypoxia-induced cardiac cell death. In conclusion, our results suggest that KR466 can protect H9c2 cells from hypoxia-induced death through mtK ATP channel opening and PKC activation.

The use of microelectrode array (MEA) to study the protective effects of potassium channel openers on metabolically compromised HL-1 cardiomyocytes

“…It is believed that PIN, a cyanoguanidine derivative, exerts its cardioprotective effect primarily via the opening of sarK ATP channels (Lin et al 2004, Matar et al 2000, Saltman et al 2000. In contrast, SDZ, a benzopyran derivative, and related compounds such as KR-31378 (Moon et al 2004), KR 466 (Jung et al 2003), BMS-191095 (Fischbach et al 2004, Neckar et al 2002 and bimakalim (Eells et al 2000) have all been shown to act specifically via the opening of mitoK ATP channels, which are more relevant to preconditioning and sustained hypoxia and ischaemia of the heart. It is very possible that while the potent hyperpolarization effect of SDZ alone could be observed, its protective effect on metabolically compromised cardiomyocytes could not be seen because the present study only dealt with acute metabolic inhibition.…”

Diazoxide acts more as a PKC‐ɛ activator, and indirectly activates the mitochondrial KATP channel conferring cardioprotection against hypoxic injury

“…To examine the extent of apoptotic cell death, we performed TUNEL‐staining after 8 and 6 h of hypoxia in H9c2 cells and neonatal rat cardiomyocytes, respectively, as described previously (Jung et al ., 2003; Kim et al ., 2005). There are three groups of diazoxide treatment.…”

Mitochondrial Potassium Channels as Pharmacological Target for Cardioprotective Drugs

“…Moreover, the benzopyranyl‐indole analog KR‐31466 reduces hypoxic injury in heart‐derived H9c2 cells through mitoK ATP opening. Jung et al suggested that this protection from hypoxia‐induced death could also involve PKC activation …”