Suppression of Aß toxicity by puromycin-sensitive aminopeptidase is independent of its proteolytic activity.

Kruppa, Antonina J; Ott, Stanislav; Chandraratna, Dhia S; Irving, James A; Page, Richard M; Speretta, Elena; Seto, Tiffany; Camargo, Luiz Miguel; Marciniak, Stefan J; Lomas, David A; Crowther, Damian C

Kruppa, Antonina J; Ott, Stanislav; Chandraratna, Dhia S; Irving, James A; Page, Richard M; Speretta, Elena; Seto, Tiffany; Camargo, Luiz Miguel; Marciniak, Stefan J; Lomas, David A; Crowther, Damian C.

Afiliación

Kruppa AJ; Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK; Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK; Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK.

Biochim Biophys Acta ; 1832(12): 2115-26, 2013 Dec.

Article en En | MEDLINE | ID: mdl-23911349

RESUMEN

The accumulation of ß-amyloid (Aß) peptide in the brain is one of the pathological hallmarks of Alzheimer's disease and is thought to be of primary aetiological significance. In an unbiased genetic screen, we identified puromycin-sensitive aminopeptidase (PSA) as a potent suppressor of Aß toxicity in a Drosophila model system. We established that coexpression of Drosophila PSA (dPSA) in the flies' brains improved their lifespan, protected against locomotor deficits, and reduced brain Aß levels by clearing the Aß plaque-like deposits. However, confocal microscopy and subcellular fractionation of amyloid-expressing 7PA2 cells demonstrated that PSA localizes to the cytoplasm. Therefore, PSA and Aß are unlikely to be in the same cellular compartment; moreover, when we artificially placed them in the same compartment in flies, we could not detect a direct epistatic interaction. The consequent hypothesis that PSA's suppression of Aß toxicity is indirect was supported by the finding that Aß is not a proteolytic substrate for PSA in vitro. Furthermore, we showed that the enzymatic activity of PSA is not required for rescuing Aß toxicity in neuronal SH-SY5Y cells. We investigated whether the stimulation of autophagy by PSA was responsible for these protective effects. However PSA's promotion of autophagosome fusion with lysosomes required proteolytic activity and so its effect on autophagy is not identical to its protection against Aß toxicity.

Asunto(s)

Enfermedad de Alzheimer/prevención & control; Aminopeptidasas/farmacología; Péptidos beta-Amiloides/efectos adversos; Encéfalo/metabolismo; Drosophila melanogaster/metabolismo; Neuroblastoma/prevención & control; Enfermedad de Alzheimer/metabolismo; Enfermedad de Alzheimer/patología; Animales; Animales Modificados Genéticamente; Autofagia; Western Blotting; Drosophila melanogaster/genética; Drosophila melanogaster/crecimiento & desarrollo; Ensayo de Inmunoadsorción Enzimática; Citometría de Flujo; Técnica del Anticuerpo Fluorescente; Humanos; Técnicas para Inmunoenzimas; Neuroblastoma/metabolismo; Neuroblastoma/patología; Neuronas/efectos de los fármacos; Neuronas/metabolismo; Neuronas/patología; Proteolisis; Puromicina/farmacología; ARN Mensajero/genética; Reacción en Cadena en Tiempo Real de la Polimerasa; Reacción en Cadena de la Polimerasa de Transcriptasa Inversa; Células Tumorales Cultivadas

Palabras clave

Alzheimer; Amyloid; Autophagy; Proteolysis; Puromycin-sensitive aminopeptidase

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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Encéfalo / Péptidos beta-Amiloides / Drosophila melanogaster / Enfermedad de Alzheimer / Aminopeptidasas / Neuroblastoma Tipo de estudio: Diagnostic_studies / Prognostic_studies Límite: Animals / Humans Idioma: En Revista: Biochim Biophys Acta Año: 2013 Tipo del documento: Article Pais de publicación: Países Bajos

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