Pim-1 regulates cardiomyocyte survival downstream of Akt

JA Muraski, M Rota, Y Misao, J Fransioli, C Cottage… - Nature medicine, 2007 - nature.com
JA Muraski, M Rota, Y Misao, J Fransioli, C Cottage, N Gude, G Esposito, F Delucchi…
Nature medicine, 2007nature.com
The serine-threonine kinases Pim-1 and Akt regulate cellular proliferation and survival.
Although Akt is known to be a crucial signaling protein in the myocardium, the role of Pim-1
has been overlooked. Pim-1 expression in the myocardium of mice decreased during
postnatal development, re-emerged after acute pathological injury in mice and was
increased in failing hearts of both mice and humans. Cardioprotective stimuli associated
with Akt activation induced Pim-1 expression, but compensatory increases in Akt abundance …
Abstract
The serine-threonine kinases Pim-1 and Akt regulate cellular proliferation and survival. Although Akt is known to be a crucial signaling protein in the myocardium, the role of Pim-1 has been overlooked. Pim-1 expression in the myocardium of mice decreased during postnatal development, re-emerged after acute pathological injury in mice and was increased in failing hearts of both mice and humans. Cardioprotective stimuli associated with Akt activation induced Pim-1 expression, but compensatory increases in Akt abundance and phosphorylation after pathological injury by infarction or pressure overload did not protect the myocardium in Pim-1–deficient mice. Transgenic expression of Pim-1 in the myocardium protected mice from infarction injury, and Pim-1 expression inhibited cardiomyocyte apoptosis with concomitant increases in Bcl-2 and Bcl-XL protein levels, as well as in Bad phosphorylation levels. Relative to nontransgenic controls, calcium dynamics were significantly enhanced in Pim-1–overexpressing transgenic hearts, associated with increased expression of SERCA2a, and were depressed in Pim-1–deficient hearts. Collectively, these data suggest that Pim-1 is a crucial facet of cardioprotection downstream of Akt.
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