title: A novel peptide inhibitor targeted to caspase-3 cleavage site of a proapoptotic kinase protein kinase C delta (PKCdelta) protects against dopaminergic neuronal degeneration in Parkinson's disease models.
abstract: Oxidative stress and apoptosis are considered common mediators of many neurodegenerative disorders including Parkinson's disease (PD). Recently, we identified that PKCdelta, a member of the novel PKC isoform family, is proteolytically activated by caspase-3 to induce apoptosis in experimental models of PD [Eur. J. Neurosci. 18 (6):1387-1401, 2003; Antioxid. Redox Signal. 5 (5):609-620, 2003]. Since caspase-3 cleaves PKCdelta between proline and aspartate residues at the cleavage site 324DIPD327 to activate the kinase, we developed an irreversible and competitive peptide inhibitor, Z-Asp(OMe)-Ile-Pro-Asp(OMe)-FMK (z-DIPD-fmk), to mimic the caspase-3 cleavage site of PKCdelta and tested its efficacy against oxidative stress-induced cell death in PD models. Cotreatment of z-DIPD-fmk with the parkinsonian toxins MPP(+) and 6-OHDA dose dependently attenuated cytotoxicity, caspase-3 activation, and DNA fragmentation in a mesencephalic dopaminergic neuronal cell model (N27 cells). However, z-DIPD-fmk treatment did not block MPP(+)-induced increases in caspase-9 enzyme activity. The z-DIPD-fmk peptide was much more potent (IC50 6 microM) than the most widely used and commercially available caspase-3 inhibitor z-DEVD-fmk (IC50 18 microM). Additionally, z-DIPD-fmk more effectively blocked PKCdelta cleavage and proteolytic activation than the cleavage of another caspase-3 substrate, poly(ADP-ribose) polymerase (PARP). Importantly, the peptide inhibitor z-DIPD-fmk completely rescued TH(+) neurons from MPP(+)- and 6-OHDA-induced toxicity in mouse primary mesencephalic cultures. Collectively, these results demonstrate that the PKCdelta cleavage site is a novel target for development of a neuroprotective therapeutic strategy for PD.
authors.affiliation: Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2008 Veterinary Medicine Building, Iowa State University, Ames, IA 50011-1250, USA. akanthas@iastate.edu
authors.forename: Anumantha G
authors.initials: AG
authors.lastname: Kanthasamy
authors.forename: Vellareddy
authors.initials: V
authors.lastname: Anantharam
authors.forename: Danhui
authors.initials: D
authors.lastname: Zhang
authors.forename: Calivarathan
authors.initials: C
authors.lastname: Latchoumycandane
authors.forename: Huajun
authors.initials: H
authors.lastname: Jin
authors.forename: Siddharth
authors.initials: S
authors.lastname: Kaul
authors.forename: Arthi
authors.initials: A
authors.lastname: Kanthasamy
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D061945:Caspase Inhibitors; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism; D008297:Male; D008636:Mesencephalon / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D009410:Nerve Degeneration / Q000201:enzymology / Q000517:prevention & control*; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D016627:Oxidopamine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D010300:Parkinson Disease / Q000201:enzymology / Q000517:prevention & control*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000187:drug effects; D051745:Protein Kinase C-delta / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D061945:Caspase Inhibitors; D009842:Oligopeptides; D010455:Peptides; D047428:Protein Kinase Inhibitors; C516668:benzyloxycarbonyl-aspartyl(OMe)-isoleucyl-prolyl-aspartyl(OMe) fluoromethylketone; D016627:Oxidopamine; D014446:Tyrosine 3-Monooxygenase; D011065:Poly(ADP-ribose) Polymerases; D051745:Protein Kinase C-delta; D015655:1-Methyl-4-phenylpyridinium; D004298:Dopamine