6-Hydroxydopamine induces cystatin C-mediated cysteine protease suppression and cathepsin D activation

• Published in: Neurochemistry international Vol. 50; no. 4; pp. 607 - 618
• Main Authors: Lee, Daniel C., Womble, Tracy A., Mason, Ceceile W., Jackson, Inneke M., Lamango, Nazarius S., Severs, Walter B., Palm, Donald E.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-03-2007; Elsevier
• Subjects: 6-OHDA; Animals; Biological and medical sciences; Caspase 3 - drug effects; Caspase 3 - metabolism; Cathepsin; Cathepsin B - drug effects; Cathepsin B - metabolism; Cathepsin D - metabolism; Cell Death - drug effects; Cell Death - physiology; Cystatin C; Cystatins - metabolism; Cysteine Endopeptidases - metabolism; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dopamine - metabolism; Down-Regulation - drug effects; Down-Regulation - physiology; Enzyme Activation - drug effects; Enzyme Activation - physiology; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Lysosomes - drug effects; Lysosomes - enzymology; Medical sciences; Neurodegeneration; Neurology; Neurons - drug effects; Neurons - enzymology; Neuroprotective Agents - pharmacology; Oxidative Stress - drug effects; Oxidative Stress - physiology; Oxidopamine - toxicity; Parkinson Disease - enzymology; Parkinson Disease - physiopathology; Parkinson's; PC12 Cells; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases - drug effects; Poly(ADP-ribose) Polymerases - metabolism; Rats; Sympatholytics - toxicity; Vertebrates: nervous system and sense organs; Parkinson's; 6-OHDA; Cathepsin; Neurodegeneration; PC12 cells; Cystatin C; Cystatin; Cysteine; Rat; Parkinson disease; Oxidopamine; Aspartic endopeptidases; Degenerative disease; Cathepsin D; Degeneration; Nervous system diseases; Enzyme; Rodentia; In vitro; Cerebral disorder; Peptidases; Vertebrata; Mammalia; Cell line; Neuron; Animal; Central nervous system disease; Hydrolases; Extrapyramidal syndrome
• ISSN: 0197-0186; 1872-9754
• DOI: 10.1016/j.neuint.2006.12.006

Alteration in the lysosomal system (LS) may represent a central mechanism in neurodegeneration. 6-Hydroxydopamine (6-OHDA) induces oxidative stress and cell death in catecholaminergic cells. The LS and caspases participate in apoptosis, although the mechanism(s) that is involved is not completely understood. Here, we show that Pheochromocytoma (PC12) cells exposed to 6-OHDA results in lysosomal dysregulation, caspase activation and cell death. Cells exposed to 6-OHDA increased expression and release of cystatin C (CC) and suppressed cathepsin B (CB). CB activity significantly declined 24
h following exposure to 6-OHDA, however neutralization of CC restored CB activity. Cathepsin D (CD) and caspase-3 activity also increased following exposure to 6-OHDA. Inhibition of CD and caspase-3 with pepstatin A (PA) and DEVD-Cho, respectively, attenuated the 6-OHDA induced cell death at 48 and 72
h. However, the CB inhibitor CA-074Me failed to protect cells. Additionally, poly-ADP-ribose polymerase (PARP) cleavage was evaluated after exposure to 6-OHDA and PA, CA-074Me, and DEVD-Cho. Only DEVD-Cho significantly decreased PARP cleavage following exposure to 6-OHDA. Hence, caspase-3 mediated PARP cleavage following exposure to 6-OHDA appears independent of CB and CD alterations. These studies suggest alternate pathways and potential therapeutic targets of cell death associated with oxidative stress, CC, and lysosomal dysregulation.