title: Cathepsin X promotes 6-hydroxydopamine-induced apoptosis of PC12 and SH-SY5Y cells.
abstract: The cysteine carboxypeptidase cathepsin X is an important player in degenerative processes under normal ageing and pathological conditions. In the present study, we investigated the potential role of cathepsin X in 6-hydroxydopamine (6-OHDA)-induced toxicity in the pheochromocytoma cell line PC12 and neuroblastoma cell line SH-SY5Y. Cells exposed to 6-OHDA demonstrated alterations in the protein level of cathepsin X and activity of cathepsin X. Downregulation of cathepsin X expression by siRNA attenuated the neuronal death caused by 6-OHDA. Treatment with specific cathepsin X inhibitor AMS36 protected cells against 6-OHDA mediated cytotoxicity, resulting in reduced cell death and apoptosis. Furthermore, AMS36 reversed 6-OHDA-induced loss of tyrosine hydroxylase and attenuated 6-OHDA-induced activation of caspase-3, triggering apoptosis, intracellular generation of reactive oxygen species and mitochondrial dysfunction, including the release of cytochrome c and an imbalanced Bax/Bcl-2 ratio. Moreover, AMS36 interfered with NF-κB activation by blocking degradation of IκBα, preventing NF-κB translocation to the nucleus. Our data provide the first evidence that inhibition of cathepsin X protects both, PC12 and SH-SY5Y cells against 6-OHDA toxicity and indicate that cathepsin X may be responsible for dopamine neuron death, involved in the pathogenic cascade event for the neurodegenerative disorders, such as Parkinson's disease.
authors: Department of Pharmaceutical Biology, Faculty of Pharmacy, University of Ljubljana, Askerceva 7, 1000 Ljubljana, Slovenia. Electronic address: anja.pislar@ffa.uni-lj.si.
authors: Anja Hafner
authors: AH
authors: Pišlar
authors: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ljubljana, Askerceva 7, 1000 Ljubljana, Slovenia.
authors: Nace
authors: N
authors: Zidar
authors: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ljubljana, Askerceva 7, 1000 Ljubljana, Slovenia.
authors: Danijel
authors: D
authors: Kikelj
authors: Department of Pharmaceutical Biology, Faculty of Pharmacy, University of Ljubljana, Askerceva 7, 1000 Ljubljana, Slovenia; Department of Biotechnology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
authors: Janko
authors: J
authors: Kos
mesh_terms: D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D056663:Cathepsin Z / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002403:Cathepsins / Q000378:metabolism; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D016328:NF-kappa B / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D016627:Oxidopamine / Q000633:toxicity*; D016716:PC12 Cells; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D013386:Succinates / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: C000621155:AMS36 compound; D000613:Aminobutyrates; C494826:BAX protein, human; C494828:Bax protein, rat; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D013386:Succinates; D051028:bcl-2-Associated X Protein; D016627:Oxidopamine; D045304:Cytochromes c; D014446:Tyrosine 3-Monooxygenase; D051550:I-kappa B Kinase; D002403:Cathepsins; D056663:Cathepsin Z; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D003546:Cysteine Endopeptidases; C404516:cathepsin Y
keywords: 6-Hydroxydopamine; Apoptosis; Cathepsin X; Mitochondrial dysfunction; Neurodegeneration; Neuroprotection