VIP-Related protection against lodoacetate toxicity in pheochromocytoma (PC12) cells: a model for ischemic/hypoxic injury.
To evaluate the protective properties of peptides related functionally and/or structurally to vasoactive intestinal peptide (VIP), PC12 cultures were treated with iodoacetate as a model for neuronal ischemic/hypoxic injury. Brain tissue can be pre-conditioned against lethal ischemia by several mechanisms including sub-lethal ischemia, moderate hypoglycemia, heat shock, and growth factors. In the present study, a superactive VIP lipophilic analog (Stearyl-Norleucine17-VIP; SNV) was used to pre-condition media of PC12 cells. After removal of the conditioned media, the cultures were exposed to iodoaceate, which inhibits glycolysis. Protective efficacy against iodoacetate-induced injury was assessed by the measurements of lactate dehydrogenase (LDH) activity in the media. Treatment with iodoacetate for 2.5 h produced a twofold increase in LDH activity in the media. The protective effect of SNV had an EC50 of 1 pM. Comparison of the preconditioning time required for full protection by SNV showed no apparent difference between a 15 min and a 2 h incubation period prior to the addition of iodoacetate. Iodoacetate treatment produced a 20% decrease in the RNA transcripts encoding activity-dependent neuroprotective protein (ADNP), a novel glia-derived protein that is regulated by VIP. The iodoacetate-associated reduction in ADNP mRNA was prevented by pre-treatment with SNV. These effects imply that SNV provides a regulatory mechanism for ADNP synthesis during glycolytic stress. Furthermore, a short exposure to SNV provided potent protection from iodoacetate-induced toxicity suggesting that SNV may have therapeutic value in the treatment of ischemic/hypoxic injury.
Sigalov
E
E
Department of Clinical Biochemistry, Sackler Medical School, Tel-Aviv University, Israel.
Fridkin
M
M
Brenneman
D E
DE
Gozes
I
I
D000818:Animals; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000633:toxicity*; D018398:Homeodomain Proteins; D007461:Iodoacetates / Q000633:toxicity*; D009410:Nerve Degeneration / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D009419:Nerve Tissue Proteins / Q000235:genetics; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins / Q000037:antagonists & inhibitors; D016716:PC12 Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D018398:Homeodomain Proteins; D007461:Iodoacetates; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D009498:Neurotoxins; D012333:RNA, Messenger; C086770:stearyl-norleucine(17)-vasoactive intestinal peptide; D014660:Vasoactive Intestinal Peptide