Cariporide (HOE642), a Selective Na ⁺ -H ⁺ Exchange Inhibitor, Inhibits the Mitochondrial Death Pathway

Abstract

Background— The Na + -H + exchanger figures prominently in cardiac ischemia-reperfusion injury. Several experimental and clinical studies have demonstrated a cardioprotective effect of Na + -H + exchanger inhibition; however, the precise mechanisms have not been established. Methods and Results— We examined the effects of cariporide (HOE642, 10 μmol/L) on cell death induced by oxidative stress (H 2 O 2 , 100 μmol/L) in cultured neonatal rat cardiomyocytes. Cariporide significantly suppressed markers of cell death, such as TUNEL positivity and caspase-3 cleavage, at 8 or 16 hours after H 2 O 2 . The early phase of cell death, reported by increases in phosphatidylserine exposure and propidium iodide uptake, was also inhibited by cariporide. To explore the mechanisms of cell protection, we examined the effects of cariporide on increases in intracellular Na + and Ca 2+ induced by oxidative stress. Cariporide remarkably suppressed cytosolic Na + and Ca 2+ accumulation. Next, we investigated the effects of cariporide on mitochondria-associated death process. Mitochondrial Ca 2+ overload induced by H 2 O 2 was remarkably suppressed by cariporide. Loss of mitochondrial membrane potential is a critical step of the death pathway; cariporide prevented mitochondrial membrane potential loss induced by H 2 O 2 . Conclusions— Cariporide protects cardiomyocytes against oxidant-induced cell death by preserving intracellular ion homeostasis and mitochondrial integrity.

KR-32570, a novel Na+/H+ exchanger-1 inhibitor, attenuates hypoxia-induced cell death through inhibition of intracellular Ca2+ overload and mitochondrial death pathway in H9c2 cells

“…In good agreement with our results, 10 μM cariporide has been previously demonstrated to attenuate the H 2 O 2 -induced increase in cytosolic and mitochondrial Ca 2+ in rat cardiomyocytes (Teshima et al, 2003). KR-32570 also significantly recovered the large reduction in ΔΨ m and cytochrome c release induced by hypoxia.…”

“…Our results that 30 μM ruthenium red inhibited mitochondrial Ca 2+ overload during hypoxia and decreased the number of TUNELpositive cells (Fig. 5), further support the pro-apoptotic role of mitochondrial Ca 2+ during hypoxia (Teshima et al, 2003). Our results further showed that treatment with ruthenium red during hypoxia prolonged the maintenance of the elevated level of cytosolic Ca 2+ over 2 h of hypoxia.…”

“…Preservation of intracellular ion homeostasis is a normal potential mechanism of cardioprotection by NHE inhibition (Teshima et al, 2003). As shown in Fig.…”

Non-canonical glycosyltransferase modulates post-hypoxic cardiac myocyte death and mitochondrial permeability transition

“…Neonatal rat cardiac myocytes (NRCMs) were isolated from 1-2 day old Sprague-Dawley rats and cultured according to a well characterized protocol [24][25][26][27][28]. The first four days of culture medium contained the anti-mitotic, BrdU (0.1 mmol/L), to inhibit fibroblast growth in addition to 5% fetal bovine serum, penicillin/streptomycin, and vitamin B 12 .…”

Cardioprotective Effects of Pravastatin Against Lethal Ventricular Arrhythmias Induced by Reperfusion in the Rat Heart

“…13 Cells were loaded with TMRE (Invitrogen) (100 nmol/L) at 37°C for 30 min. After 1 h pretreatment with pravastatin (10 nmol/L), scanning began with the application of H2O2 (100 μmol/L), and TMRE fluorescence intensity was measured every 1 min (568-nm line of a HeNe laser).…”