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Modulation of cardiac Na+, K+‐ATPase and cell viability by Ischemia/Reperfusion Injury and Ouabain Preconditioning
Author(s) -
Pierre Sandrine V,
Belliard Aude,
Sottejeau Yoann,
Duan Qiming
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.883.2
Subject(s) - ouabain , viability assay , myocyte , chemistry , atpase , sarcolemma , cell , reperfusion injury , programmed cell death , annexin , microbiology and biotechnology , ischemia , biophysics , biochemistry , biology , medicine , apoptosis , enzyme , sodium , organic chemistry
Na + , K + ‐ATPase and cell survival were investigated in a cellular model of ischemia‐reperfusion (IR)‐induced injury and protection by ouabain‐induced preconditioning (OPC). Rat neonatal cardiac myocytes were subjected to 30 minutes of substrate and coverslip‐induced ischemia followed by 30 min of reperfusion. This significantly compromised cell viability as documented by LDH release and Annexin V/PI staining. Total Na + , K + ‐ATPase α1‐ polypeptide expression remained unchanged, but cell surface biotinylation and immunostaining studies showed a significant decrease in cell surface abundance. Na + , K + ‐ATPase‐activity and 86 Rb + transport in live cells were decreased by about 30%. OPC increased cell viability by about 40% in a PKCε‐dependent manner and prevented IR‐induced modulation of Na + , K + ‐ATPase activity and surface expression. However, it did not prevent IR‐induced decrease of 86 Rb + transport, suggesting that the protection against cell death was not conferred by increased Na + , K + ‐ATPase‐mediated ion transport capacity at the cell membrane. Consistent with this observation, transient expression of a mutant form of Na + , K + ‐ATPase α1 with increased surface abundance without increased ion transport activity successfully reduced IR‐induced cell death. These results suggest that maintenance of Na + , K + ‐ ATPase cell surface abundance is critical to myocyte survival after an ischemic attack and plays a role in OPC‐induced protection. They further suggest that the protection conferred by increased surface expression may be independent of ion transport.