Combination therapy targeting Akt and mammalian target of rapamycin improves functional outcome after controlled cortical impact in mice

J Cereb Blood Flow Metab. 2012 Feb;32(2):330-40. doi: 10.1038/jcbfm.2011.131. Epub 2011 Sep 21.

Abstract

Akt and mammalian target of rapamycin (mTOR) are both activated after traumatic brain injury (TBI), however complex interplay between the two hampers deciphering their functional implications in vivo. We examined the effects of single and combination inhibitors of Akt/mTOR in a mouse controlled cortical impact (CCI) model. Following CCI, phospho-Akt-473 (p-Akt) and -S6 ribosomal protein (p-S6RP), a downstream substrate of mTOR, were increased in cortical and hippocampal brain homogenates (P<0.05 versus sham). At 24 hours, p-S6RP was detected in neurons and was robustly induced in microglia and astrocytes in injured hippocampus. In vivo activity of Akt and mTOR inhibitors administered separately was confirmed by reduced expression of p-GSK3β (P<0.01) or p-S6RP (P<0.05), respectively, after CCI. Importantly, administration of Akt and mTOR inhibitors together (but not of either alone) improved postinjury motor (P=0.02) and cognitive deficits (hidden platform trials, P=0.001; probe trials, P<0.05), decreased propidium iodide-positive cells in CA1 and CA3 (P<0.005), and unexpectedly increased p-GSK3β in hippocampus. Although the roles of Akt and mTOR in the pathogenesis of TBI remain to be fully elucidated, dual inhibition of Akt and mTOR may have therapeutic potential for TBI.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Brain / drug effects
  • Brain / pathology
  • Brain Injuries / drug therapy*
  • Brain Injuries / pathology
  • Drug Synergism
  • Enzyme Inhibitors / pharmacology
  • Enzyme Inhibitors / therapeutic use*
  • Male
  • Memory / drug effects
  • Mice
  • Mice, Inbred C57BL
  • Motor Activity / drug effects
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Signal Transduction / drug effects
  • TOR Serine-Threonine Kinases / antagonists & inhibitors*
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • Enzyme Inhibitors
  • mTOR protein, mouse
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases