Wild type and mutant amyloid precursor proteins influence downstream effects of proteasome and autophagy inhibition.
Cells rely on complementary proteolytic pathways including the ubiquitin-proteasome system and autophagy to maintain proper protein degradation. There is known to be considerable interplay between them, whereby the loss of one clearance system results in compensatory changes in other proteolytic pathways of the cell. Disturbances in proteolysis are known to occur in Alzheimer's disease, and potentially contribute to neurophysiological and neurodegenerative processes. Currently, few data are available on how the presence of wild type and mutant amyloid precursor protein (APPwt and APPmut) potentially alters the reciprocal interplay between the different intracellular proteolytic pathways. This study used human SH-SY5Y neuronal cell lines, and SH-SY5Y transfected with either APPwt or APPmut (valine-to-glycine substitution at position 717), in order to explore if the presence of APPwt or APPmut altered the downstream effects of pharmacological proteasome or autophagy inhibition. The occurrence of APPwt or APPmut was observed to disturb proteasome or autophagy activities upon treatment with proteasome inhibitors or authophagy inhibitors. Interestingly, APPwt and APPmut expression was observed to significantly and robustly enhance the induction in cathepsin B following the administration of an established proteasome inhibitor. The presence of APPwt and APPmut also significantly reduced the elevation in ubiquitinated proteins following proteasome inhibitor treatments. Our data strongly suggest that APP is able to affect the downstream effects of protease inhibition in neural cells including enhancement of cathepsin B activity, with these changes in cathepsin B significantly and inversely related to the levels of ubiquitinated protein.
School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino, Italy. Electronic address: valentina.cecarini@unicam.it.
Valentina
V
Cecarini
School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino, Italy.
Laura
L
Bonfili
School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino, Italy.
Massimiliano
M
Cuccioloni
School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino, Italy.
Matteo
M
Mozzicafreddo
School of Medical Veterinary Sciences, University of Camerino, 62024 Matelica, Italy.
Giacomo
G
Rossi
Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA.
Jeffrey N
JN
Keller
School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino, Italy.
Mauro
M
Angeletti
School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino, Italy.
Anna Maria
AM
Eleuteri
D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D019943:Amino Acid Substitution; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western; D002401:Cathepsin B / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D007976:Leupeptins / Q000494:pharmacology; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D059748:Proteolysis / Q000187:drug effects
D016564:Amyloid beta-Protein Precursor; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D050505:Mutant Proteins; C025946:3-methyladenine; D002401:Cathepsin B; D046988:Proteasome Endopeptidase Complex; D000225:Adenine; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde
3-methyladenine; 3MA; AP-N; APP; Amyloid precursor protein; Autophagy; Aβ; BrAAP; Cathepsin B; ChT-L; IHC; PGPH; T-L; UPS; Ubiquitin–proteasome system; aminopeptidase N; amyloid precursor protein; amyloid-β; branched-chain amino acids preferring; chymotrypsin-like; immunohistochemistry; peptidylglutamyl-peptide hydrolyzing; trypsin-like; ubiquitin–proteasome system