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.
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.
Kanthasamy
Anumantha G
AG
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
Anantharam
Vellareddy
V
Zhang
Danhui
D
Latchoumycandane
Calivarathan
C
Jin
Huajun
H
Kaul
Siddharth
S
Kanthasamy
Arthi
A
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
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