Document Type

Article

Language

eng

Publication Date

12-2014

Publisher

Public Library of Science (PLoS)

Source Publication

PLoS One

Source ISSN

1932-6203

Original Item ID

DOI: 10.1371/journal.pone.0113534; PubMed Central, PMCID: PMC4250075

Abstract

Aim

Excess mitochondrial reactive oxygen species (mROS) play a vital role in cardiac ischemia reperfusion (IR) injury. P66Shc, a splice variant of the ShcA adaptor protein family, enhances mROS production by oxidizing reduced cytochrome c to yield H2O2. Ablation of p66Shc protects against IR injury, but it is unknown if and when p66Shc is activated during cardiac ischemia and/or reperfusion and if attenuating complex I electron transfer or deactivating PKCβ alters p66Shc activation during IR is associated with cardioprotection.

Methods

Isolated guinea pig hearts were perfused and subjected to increasing periods of ischemia and reperfusion with or without amobarbital, a complex I blocker, or hispidin, a PKCβ inhibitor. Phosphorylation of p66Shc at serine 36 and levels of p66Shc in mitochondria and cytosol were measured. Cardiac functional variables and redox states were monitored online before, during and after ischemia. Infarct size was assessed in some hearts after 120 min reperfusion.

Results

Phosphorylation of p66Shc and its translocation into mitochondria increased during reperfusion after 20 and 30 min ischemia, but not during ischemia only, or during 5 or 10 min ischemia followed by 20 min reperfusion. Correspondingly, cytosolic p66Shc levels decreased during these ischemia and reperfusion periods. Amobarbital or hispidin reduced phosphorylation of p66Shc and its mitochondrial translocation induced by 30 min ischemia and 20 min reperfusion. Decreased phosphorylation of p66Shc by amobarbital or hispidin led to better functional recovery and less infarction during reperfusion.

Conclusion

Our results show that IR activates p66Shc and that reversible blockade of electron transfer from complex I, or inhibition of PKCβ activation, decreases p66Shc activation and translocation and reduces IR damage. These observations support a novel potential therapeutic intervention against cardiac IR injury.

Comments

Published version. PLoS One, Vol. 9, No. 12 (December 2014): e113534. DOI.

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