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Autophagic vacuoles are enriched in amyloid precursor protein-secretase activities: implications for beta-amyloid peptide over-production and localization in Alzheimer's disease.
Int J Biochem Cell Biol. 2004 Dec; 36(12):2531-40.IJ

Abstract

In Alzheimer's disease (AD), the neuropathologic hallmarks of beta-amyloid deposition and neurofibrillary degeneration are associated with early and progressive pathology of the endosomal-lysosomal system. Abnormalities of autophagy, a major pathway to lysosomes for protein and organelle turnover, include marked accumulations of autophagy-related vesicular compartments (autophagic vacuoles or AVs) in affected neurons. Here, we investigated the possibility that AVs contain the proteases and substrates necessary to cleave the amyloid precursor protein (APP) to A beta peptide that forms beta-amyloid, a key pathogenic factor in AD. AVs were highly purified using a well-established metrizamide gradient procedure from livers of transgenic YAC mice overexpressing wild-type human APP. By Western blot analysis, AVs contained APP, beta CTF - the beta-cleaved carboxyl-terminal domain of APP, and BACE, the protease-mediating beta-cleavage of APP. beta-Secretase activity measured against a fluorogenic peptide was significantly enriched in the AV fraction relative to whole-liver lysate. Compared to other recovered subcellular fractions, AVs exhibited the highest specific activity of gamma-secretase based on a fluorogenic assay and inhibition by a specific inhibitor of gamma-secretase, DAPT. AVs were also the most enriched subcellular fraction in levels of the gamma-secretase components presenilin and nicastrin. Immunoelectron microscopy demonstrated selective immunogold labeling of AVs with antibodies specific for the carboxyl termini of human A beta 40 and A beta 42. These data indicate that AVs are a previously unrecognized and potentially highly active compartment for A beta generation and suggest that the abnormal accumulation of AVs in affected neurons of the AD brain contributes to beta-amyloid deposition.

Authors+Show Affiliations

Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15325590

Citation

Yu, W H., et al. "Autophagic Vacuoles Are Enriched in Amyloid Precursor Protein-secretase Activities: Implications for Beta-amyloid Peptide Over-production and Localization in Alzheimer's Disease." The International Journal of Biochemistry & Cell Biology, vol. 36, no. 12, 2004, pp. 2531-40.
Yu WH, Kumar A, Peterhoff C, et al. Autophagic vacuoles are enriched in amyloid precursor protein-secretase activities: implications for beta-amyloid peptide over-production and localization in Alzheimer's disease. Int J Biochem Cell Biol. 2004;36(12):2531-40.
Yu, W. H., Kumar, A., Peterhoff, C., Shapiro Kulnane, L., Uchiyama, Y., Lamb, B. T., Cuervo, A. M., & Nixon, R. A. (2004). Autophagic vacuoles are enriched in amyloid precursor protein-secretase activities: implications for beta-amyloid peptide over-production and localization in Alzheimer's disease. The International Journal of Biochemistry & Cell Biology, 36(12), 2531-40.
Yu WH, et al. Autophagic Vacuoles Are Enriched in Amyloid Precursor Protein-secretase Activities: Implications for Beta-amyloid Peptide Over-production and Localization in Alzheimer's Disease. Int J Biochem Cell Biol. 2004;36(12):2531-40. PubMed PMID: 15325590.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Autophagic vacuoles are enriched in amyloid precursor protein-secretase activities: implications for beta-amyloid peptide over-production and localization in Alzheimer's disease. AU - Yu,W H, AU - Kumar,A, AU - Peterhoff,C, AU - Shapiro Kulnane,L, AU - Uchiyama,Y, AU - Lamb,B T, AU - Cuervo,A M, AU - Nixon,R A, PY - 2004/03/26/received PY - 2004/05/20/revised PY - 2004/05/21/accepted PY - 2004/8/25/pubmed PY - 2005/2/17/medline PY - 2004/8/25/entrez SP - 2531 EP - 40 JF - The international journal of biochemistry & cell biology JO - Int. J. Biochem. Cell Biol. VL - 36 IS - 12 N2 - In Alzheimer's disease (AD), the neuropathologic hallmarks of beta-amyloid deposition and neurofibrillary degeneration are associated with early and progressive pathology of the endosomal-lysosomal system. Abnormalities of autophagy, a major pathway to lysosomes for protein and organelle turnover, include marked accumulations of autophagy-related vesicular compartments (autophagic vacuoles or AVs) in affected neurons. Here, we investigated the possibility that AVs contain the proteases and substrates necessary to cleave the amyloid precursor protein (APP) to A beta peptide that forms beta-amyloid, a key pathogenic factor in AD. AVs were highly purified using a well-established metrizamide gradient procedure from livers of transgenic YAC mice overexpressing wild-type human APP. By Western blot analysis, AVs contained APP, beta CTF - the beta-cleaved carboxyl-terminal domain of APP, and BACE, the protease-mediating beta-cleavage of APP. beta-Secretase activity measured against a fluorogenic peptide was significantly enriched in the AV fraction relative to whole-liver lysate. Compared to other recovered subcellular fractions, AVs exhibited the highest specific activity of gamma-secretase based on a fluorogenic assay and inhibition by a specific inhibitor of gamma-secretase, DAPT. AVs were also the most enriched subcellular fraction in levels of the gamma-secretase components presenilin and nicastrin. Immunoelectron microscopy demonstrated selective immunogold labeling of AVs with antibodies specific for the carboxyl termini of human A beta 40 and A beta 42. These data indicate that AVs are a previously unrecognized and potentially highly active compartment for A beta generation and suggest that the abnormal accumulation of AVs in affected neurons of the AD brain contributes to beta-amyloid deposition. SN - 1357-2725 UR - https://www.unboundmedicine.com/medline/citation/15325590/Autophagic_vacuoles_are_enriched_in_amyloid_precursor_protein_secretase_activities:_implications_for_beta_amyloid_peptide_over_production_and_localization_in_Alzheimer's_disease_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1357272504002316 DB - PRIME DP - Unbound Medicine ER -