H₂S preconditioning-induced PKC activation regulates intracellular calcium handling in rat cardiomyocytes

Abstract

The present study was aimed to investigate the regulatory effect of protein kinase C (PKC) on intracellular Ca(2+) handling in hydrogen sulfide (H(2)S)-preconditioned cardiomyocytes and its consequent effects on ischemia challenge. Immunoblot analysis was used to assess PKC isoform translocation in the rat cardiomyocytes 20 h after NaHS (an H(2)S donor, 10(-4) M) preconditioning (SP, 30 min). Intracellular Ca(2+) was measured with a spectrofluorometric method using fura-2 ratio as an indicator. Cell length was compared before and after ischemia-reperfusion insults to indicate the extent of hypercontracture. SP motivated translocation of PKCalpha, PKCepsilon, and PKCdelta to membrane fraction but only translocation of PKCepsilon and PKCdelta was abolished by an ATP-sensitive potassium channel blocker glibenclamide. It was also found that SP significantly accelerated the decay of both electrically and caffeine-induced intracellular [Ca(2+)] transients, which were reversed by a selective PKC inhibitor chelerythrine. These data suggest that SP facilitated Ca(2+) removal via both accelerating uptake of Ca(2+) into sarcoplasmic reticulum and enhancing Ca(2+) extrusion through Na(+)/Ca(2+) exchanger in a PKC-dependent manner. Furthermore, blockade of PKC also attenuated the protective effects of SP against Ca(2+) overload during ischemia and against myocyte hypercontracture at the onset of reperfusion. We demonstrate for the first time that SP activates PKCalpha, PKCepsilon, and PKCdelta in cardiomyocytes via different signaling mechanisms. Such PKC activation, in turn, protects the heart against ischemia-reperfusion insults at least partly by ameliorating intracellular Ca(2+) handling.

Mitochondrial KATPchannel inhibition blunts arrhythmia protection in ischemic exercised hearts

“…Since adaptations to exercise include cellular ATP preservation during IR, it is plausible that ATP-independent stimuli are responsible for mito K ATP channel opening in the exercised heart (9 -10, 28 -30). Mito K ATP channels, for instance, can open in response to a variety of stimuli, independent of a drop in cellular ATP, including PKC⑀ (33,38). In support, application of a short-term exercise regimen similar to the current training protocol resulted in PKC⑀ overexpression in the heart (16).…”

Hydrogen Sulfide Regulates Na+/H+ Exchanger Activity via Stimulation of Phosphoinositide 3-Kinase/Akt and Protein Kinase G Pathways

“…Compared with NHE inhibitors, H 2 S may have better clinical application potential. This is because, apart from inhibition of NHE-1, H 2 S also protects the heart via suppression of ␤-adrenoceptor function and stimulation of various protein kinases and cardioprotective mediators such as prostaglandin E 2 and NO Hu et al, 2008;Pan et al, 2008Pan et al, , 2009Yong et al, 2008b). In addition, H 2 S has been found to be useful in treating renin-dependent hypertension (Lu et al, 2010b), chronic heart failure (Calvert et al, 2010), and hypertrophy (Shi et al, 2007).…”

Hydrogen sulfide impairs keratinocyte cell growth and adhesion inhibiting mitogen-activated protein kinase signaling

“…15 Although the mechanism of this protection is-at least in part-related to the ability of H 2 S to activate myocardial K ATP channels, the extracellular signal-regulated protein kinase (ERK), phosphatidylinositol 3-kinase (PI3K)/Akt and protein kinase C (PKC) pathways seem to be involved as well. 16,17 Different intracellular signaling pathways produce a combination of anti-apoptotic and anti-inflammatory effects based on the inhibition of caspase 9, p38 MAPK and c-Jun N-terminal kinase (JNK) activation, as well as of NF-kB nuclear traslocation and leukocyte accumulation in infarct areas. 18 Recently, however, it has been reported that in pancreatic acinar cells the activation of ERKs promotes cell survival, whereas the activation of JNKs and p38 MAPK leads to H 2 S-induced apoptosis.…”