Phosphatidylinositol 3-kinase-mediated regulation of neuronal apoptosis and necrosis by insulin and IGF-I

Bo Rum Ryu, Hyuk Wan Ko, Ilo Jou, Jai Sung Noh, Byoung Joo Gwag

Research output: Contribution to journalArticle

93 Citations (Scopus)

Abstract

We examined effects of two insulin-like growth factors, insulin and insulin-like growth factor-I (IGF-I), against apoptosis, excitotoxicity, and free radical neurotoxicity in cortical cell cultures. Like IGF-I, insulin attenuated serum deprivation-induced neuronal apoptosis in a dose-dependent manner at 10-100 ng/mL. The anti-apoptosis effect of insulin against serum deprivation disappeared by addition of a broad protein kinase inhibitor, staurosporine, but not by calphostin C, a selective protein kinase C inhibitor. Addition of PD98059, a mitogen-activated protein kinase kinase (MAPKK) inhibitor, blocked insulin-induced activation of extracellular signal-regulated protein kinases (ERK1/2) without altering the neuroprotective effect of insulin. Cortical neurons underwent activation of phosphatidylinositol (PI) 3-kinase as early as 1 min after exposure to insulin. Inclusion of wortmannin or LY294002, selective inhibitors of PI 3- K, reversed the insulin effect against apoptosis. In contrast to the anti- apoptosis effect, neither insulin nor IGF-I Protected excitotoxic neuronal necrosis following continuous exposure to 15 μM N-methyl-D-aspartate or 40 μM kainate for 24 h. Surprisingly, concurrent inclusion of 50 ng/mL insulin or IGF-I aggravated free radical-induced neuronal necrosis over 24 h following continuous exposure to 10 μM Fe2+ or 100 μM buthionine sulfoximine. Wortmannin or LY294002 also reversed this potentiation effect of insulin. These results suggest that insulin-like growth factors act as anti- apoptosis factor and pro-oxidant depending uon the activation of PI 3- kinase.

Original languageEnglish
Pages (from-to)536-546
Number of pages11
JournalJournal of Neurobiology
Volume39
Issue number4
DOIs
Publication statusPublished - 1999 Jun 15

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Cellular and Molecular Neuroscience

Fingerprint Dive into the research topics of 'Phosphatidylinositol 3-kinase-mediated regulation of neuronal apoptosis and necrosis by insulin and IGF-I'. Together they form a unique fingerprint.

  • Cite this