Pim-1 regulates cardiomyocyte survival downstream of Akt

Nat Med. 2007 Dec;13(12):1467-75. doi: 10.1038/nm1671. Epub 2007 Nov 25.

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-X(L) 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Cell Nucleus / metabolism
  • Humans
  • Mice
  • Mice, Knockout
  • Myocardium / metabolism
  • Myocytes, Cardiac / metabolism*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Proto-Oncogene Proteins c-pim-1 / biosynthesis
  • Proto-Oncogene Proteins c-pim-1 / physiology*
  • Rats
  • bcl-X Protein / metabolism

Substances

  • Proto-Oncogene Proteins c-bcl-2
  • bcl-X Protein
  • PIM1 protein, human
  • Pim1 protein, mouse
  • Pim1 protein, rat
  • Proto-Oncogene Proteins c-akt
  • Proto-Oncogene Proteins c-pim-1