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Remote ischemic preconditioning of cardiomyocytes inhibits the mitochondrial permeability transition pore independently of reduced calcium-loading or sarcKATP channel activation.

Turrell HE, Thaitirarot C, Crumbie H, Rodrigo G - Physiol Rep (2014)

Bottom Line: However, only conventional-IPC reduced the Ca(2+)-loading during metabolic inhibition and this was independent of any change in sarcKATP channel activity but was associated with a reduction in Na(+)-loading, reflecting a decrease in Na/H exchanger activity.These data show that remote-IPC inhibits MPT pore opening to a similar degree as conventional IPC, however, the contribution of MPT pore inhibition to protection against reperfusion injury is independent of Ca(2+)-loading in remote IPC.We suggest that inhibition of the MPT pore and not Ca(2+)-loading is the common link in cardioprotection between conventional and remote IPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK.

No MeSH data available.


Related in: MedlinePlus

Remote ischemic preconditioning causes translocation of PKCε (A) A representative western blot of protein extracted from naïve myocytes, rIPC myocytes, and rIPC myocytes + L‐NAME (L‐NAME present during the remote conditioning phase) and PMA treated naïve‐myocytes. (B) Bar chart of the percentage translocation of PKCε, calculated from the disappearance of PKCε from the cytosol, when compared with naïve‐myocytes, from control naïve myocytes (black); rIPC myocytes (light gray); rIPC myocytes conditioned in the presence of L‐NAME (pale‐gray diamonds) and myocytes treated with PMA (black/white checks). The cytosolic fraction contained the fraction of PKCε that is not translocated to the particulate (membrane) fraction and is normalized to α‐tubulin present in the cytosolic fraction. (C) Bar chart of percentage necrotic cells (PI positive) for control naïve myocytes (black); rIPC myocytes (light‐gray); rIPC conditioned in the presence of PKCεV1‐2 (pale‐gray hashed) or L‐NAME (pale‐gray diamonds). Mean ± SEM; *P < 0.05, **P < 0.01, one‐way ANOVA followed by Tukey's post hoc test for significance.
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fig07: Remote ischemic preconditioning causes translocation of PKCε (A) A representative western blot of protein extracted from naïve myocytes, rIPC myocytes, and rIPC myocytes + L‐NAME (L‐NAME present during the remote conditioning phase) and PMA treated naïve‐myocytes. (B) Bar chart of the percentage translocation of PKCε, calculated from the disappearance of PKCε from the cytosol, when compared with naïve‐myocytes, from control naïve myocytes (black); rIPC myocytes (light gray); rIPC myocytes conditioned in the presence of L‐NAME (pale‐gray diamonds) and myocytes treated with PMA (black/white checks). The cytosolic fraction contained the fraction of PKCε that is not translocated to the particulate (membrane) fraction and is normalized to α‐tubulin present in the cytosolic fraction. (C) Bar chart of percentage necrotic cells (PI positive) for control naïve myocytes (black); rIPC myocytes (light‐gray); rIPC conditioned in the presence of PKCεV1‐2 (pale‐gray hashed) or L‐NAME (pale‐gray diamonds). Mean ± SEM; *P < 0.05, **P < 0.01, one‐way ANOVA followed by Tukey's post hoc test for significance.

Mentions: Involvement of PKCε signaling in conventional and remote IPC is well documented (Wolfrum et al. 2002; Inagaki et al. 2006). We determined to look at the role of PKCε in our rIPC myocytes as further support to the validity of our model for remote IPC. Myocytes were isolated from hearts subject to conventional IPC (three cycles of 5 min ischemia and 5 min of reperfusion). Naïve myocytes were isolated from control hearts and these were either remotely conditioned for 15 min to produce rIPC‐myocytes or treated with PMA (1 μmol/L) as a positive control. Western blot analysis of PKCε shows significant translocation from the cytosolic fraction to the particulate fraction in rIPC myocytes comparable to that in conventional IPC myocytes (Figure 7A). The data were quantified using densitometry readings of PKCε bands and calculating the disappearance of PKCe from the cytosolic fraction (naïve‐treated), which was then expressed as a percentage on the naïve band (Figure 7B).


Remote ischemic preconditioning of cardiomyocytes inhibits the mitochondrial permeability transition pore independently of reduced calcium-loading or sarcKATP channel activation.

Turrell HE, Thaitirarot C, Crumbie H, Rodrigo G - Physiol Rep (2014)

Remote ischemic preconditioning causes translocation of PKCε (A) A representative western blot of protein extracted from naïve myocytes, rIPC myocytes, and rIPC myocytes + L‐NAME (L‐NAME present during the remote conditioning phase) and PMA treated naïve‐myocytes. (B) Bar chart of the percentage translocation of PKCε, calculated from the disappearance of PKCε from the cytosol, when compared with naïve‐myocytes, from control naïve myocytes (black); rIPC myocytes (light gray); rIPC myocytes conditioned in the presence of L‐NAME (pale‐gray diamonds) and myocytes treated with PMA (black/white checks). The cytosolic fraction contained the fraction of PKCε that is not translocated to the particulate (membrane) fraction and is normalized to α‐tubulin present in the cytosolic fraction. (C) Bar chart of percentage necrotic cells (PI positive) for control naïve myocytes (black); rIPC myocytes (light‐gray); rIPC conditioned in the presence of PKCεV1‐2 (pale‐gray hashed) or L‐NAME (pale‐gray diamonds). Mean ± SEM; *P < 0.05, **P < 0.01, one‐way ANOVA followed by Tukey's post hoc test for significance.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4255825&req=5

fig07: Remote ischemic preconditioning causes translocation of PKCε (A) A representative western blot of protein extracted from naïve myocytes, rIPC myocytes, and rIPC myocytes + L‐NAME (L‐NAME present during the remote conditioning phase) and PMA treated naïve‐myocytes. (B) Bar chart of the percentage translocation of PKCε, calculated from the disappearance of PKCε from the cytosol, when compared with naïve‐myocytes, from control naïve myocytes (black); rIPC myocytes (light gray); rIPC myocytes conditioned in the presence of L‐NAME (pale‐gray diamonds) and myocytes treated with PMA (black/white checks). The cytosolic fraction contained the fraction of PKCε that is not translocated to the particulate (membrane) fraction and is normalized to α‐tubulin present in the cytosolic fraction. (C) Bar chart of percentage necrotic cells (PI positive) for control naïve myocytes (black); rIPC myocytes (light‐gray); rIPC conditioned in the presence of PKCεV1‐2 (pale‐gray hashed) or L‐NAME (pale‐gray diamonds). Mean ± SEM; *P < 0.05, **P < 0.01, one‐way ANOVA followed by Tukey's post hoc test for significance.
Mentions: Involvement of PKCε signaling in conventional and remote IPC is well documented (Wolfrum et al. 2002; Inagaki et al. 2006). We determined to look at the role of PKCε in our rIPC myocytes as further support to the validity of our model for remote IPC. Myocytes were isolated from hearts subject to conventional IPC (three cycles of 5 min ischemia and 5 min of reperfusion). Naïve myocytes were isolated from control hearts and these were either remotely conditioned for 15 min to produce rIPC‐myocytes or treated with PMA (1 μmol/L) as a positive control. Western blot analysis of PKCε shows significant translocation from the cytosolic fraction to the particulate fraction in rIPC myocytes comparable to that in conventional IPC myocytes (Figure 7A). The data were quantified using densitometry readings of PKCε bands and calculating the disappearance of PKCe from the cytosolic fraction (naïve‐treated), which was then expressed as a percentage on the naïve band (Figure 7B).

Bottom Line: However, only conventional-IPC reduced the Ca(2+)-loading during metabolic inhibition and this was independent of any change in sarcKATP channel activity but was associated with a reduction in Na(+)-loading, reflecting a decrease in Na/H exchanger activity.These data show that remote-IPC inhibits MPT pore opening to a similar degree as conventional IPC, however, the contribution of MPT pore inhibition to protection against reperfusion injury is independent of Ca(2+)-loading in remote IPC.We suggest that inhibition of the MPT pore and not Ca(2+)-loading is the common link in cardioprotection between conventional and remote IPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK.

No MeSH data available.


Related in: MedlinePlus