C-terminal mechano-growth factor induces heme oxygenase-1-mediated neuroprotection of SH-SY5Y cells via the protein kinase Cϵ/Nrf2 pathway.
Recently, a variant of insulin-like growth factor-1, mechano-growth factor (MGF), has been discovered whose 24-amino-acid carboxy end is protective in models of stroke, nerve injury, and amyotrophic lateral sclerosis, suggesting broad-spectrum neuroprotective properties. Moreover, we recently demonstrated in vitro and in vivo that a modified protease-resistant 24-amino-acid MGF derivative (MGF24) protects dopaminergic neurons from oxidative stress-induced apoptosis via induction of the stress response protein heme oxygenase-1. However, the underlying mechanism by which MGF24 up-regulates heme oxygenase-1 expression is unknown. In this study, we demonstrate that MGF24-induced heme oxygenase-1 up-regulation is dependent on activation of protein kinase Cϵ and NF-E2-related factor-2 (Nrf2). MGF24 induces nuclear translocation of Nrf2, and siRNA knockdown of Nrf2 or of heme oxygenase-1 prevents MGF24-induced heme oxygenase-1 up-regulation and neuroprotection of SH-SY5Y cells against 6-hydroxydopamine-induced cell death. Pharmacological inhibition of ERK, p38 MAPK, PI3K/Akt, or PKC signaling revealed that only PKC inhibition by GF109203X prevents MGF24's ability to protect against 6-hydroxydopamine-induced cell death. GF109203X also prevented MGF24-induced Nrf2 nuclear translocation and heme oxygenase-1 up-regulation. siRNA knockdown of protein kinase Cϵ blocks MGF24-induced Nfr2 nuclear translocation, heme oxygenase-1 expression, and neuroprotection. Taken together, these results demonstrate that PKC activity is needed for MGF24's activation of Nrf2, which in turn increases heme oxygenase-1 expression, a critical event in mediating MGF24's neuroprotection against 6-hydroxydopamine-induced apoptosis.
Department of Neurobiology, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California, USA. arnulfo.quesada@va.gov
Arnulfo
A
Quesada
Julie
J
Ogi
James
J
Schultz
Adrian
A
Handforth
D000704:Analysis of Variance; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000737:chemistry / Q000378:metabolism*; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D009447:Neuroblastoma; D018696:Neuroprotective Agents / Q000494:pharmacology; D016627:Oxidopamine / Q000633:toxicity; D010446:Peptide Fragments / Q000494:pharmacology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013565:Sympatholytics / Q000633:toxicity; D014162:Transfection / Q000379:methods; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*
D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D018696:Neuroprotective Agents; D010446:Peptide Fragments; D034741:RNA, Small Interfering; D013565:Sympatholytics; D007334:Insulin-Like Growth Factor I; D016627:Oxidopamine; D051547:Heme Oxygenase-1; D011494:Protein Kinases