title: Prevention of cytosolic IAPs degradation: a potential pharmacological target in Huntington's Disease.
abstract: Huntington's Disease (HD) is a neurodegenerative disorder caused by an abnormally expanded polyglutamine trait in the amino-terminal region of huntingtin. Pathogenic mechanisms involve a gained toxicity of mutant huntingtin and a potentially reduced neuroprotective function of the wild-type allele. Among the molecular abnormalities reported, HD cells are characterized by the presence of aggregates, transcriptional dysregulation, altered mitochondrial membrane potential and aberrant Ca++ handling. In addition, upon exposure to toxic stimuli, increased mitochondrial release of cytochrome C and activation of caspase-9 and caspase-3 are found in HD cells and tissue. Here we report that HTRA2 and Smac/DIABLO, two additional mitochondrial pro-apoptotic factors, are aberrantly released from brain-derived cells expressing mutant huntingtin. This event causes a reduction in levels of the cytosolic IAP1 (Inhibitor of Apoptosis Protein-1) and XIAP (X-linked inhibitor apoptosis) antiapoptotic IAP family members. Reduced IAP levels are also found in post-mortem HD brain tissue. Treatment with ucf101, a serine protease HTRA2 specific inhibitor, counteracts IAPs degradation in HD cells and increases their survival. These results point to the IAPs as potential pharmacological targets in Huntington's Disease.
authors.affiliation: Department of Pharmacological Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milano, Via Balzaretti 9, 20133 Milano, Italy.
authors.forename: Donato
authors.initials: D
authors.lastname: Goffredo
authors.forename: Dorotea
authors.initials: D
authors.lastname: Rigamonti
authors.forename: Chiara
authors.initials: C
authors.lastname: Zuccato
authors.forename: Marzia
authors.initials: M
authors.lastname: Tartari
authors.forename: Marta
authors.initials: M
authors.lastname: Valenza
authors.forename: Elena
authors.initials: E
authors.lastname: Cattaneo
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival; D016572:Cyclosporine / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D000074923:High-Temperature Requirement A Serine Peptidase 2; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics / Q000378:metabolism*; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011744:Pyrimidinones / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000378:metabolism*; D013871:Thiones / Q000494:pharmacology; D044767:Ubiquitin-Protein Ligases; D051636:X-Linked Inhibitor of Apoptosis Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; C412403:DIABLO protein, human; C499605:Diablo protein, mouse; C086055:HTT protein, human; C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011744:Pyrimidinones; D013871:Thiones; C501517:UCF 101; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; D016572:Cyclosporine; C494833:BIRC2 protein, human; C494834:Birc2 protein, mouse; D044767:Ubiquitin-Protein Ligases; D012697:Serine Endopeptidases; C000615914:HTRA2 protein, human; D000074923:High-Temperature Requirement A Serine Peptidase 2; C000615915:Htra2 protein, mouse