ABSTRACT
We previously discovered the implication of membrane-type 5-matrix metalloproteinase (MT5-MMP) in Alzheimer’s disease AD pathogenesis. Here we shed new light on pathogenic mechanisms by which MT5-MMP controls APP processing and the fate of amyloid beta peptide (Aβ), its precursor C99 and C83. We found in HEK carrying the APP Swedish familial mutation (HEKswe) that MT5-MMP-mediated processing of APP that releases the soluble 95 kDa form (sAPP95), was hampered by the removal of the C-terminal non-catalytic domains of MT5-MMP. Catalytically inactive MT5-MMP variants increased the levels of Aβ and promoted APP/C99 sorting in the endo-lysosomal system. We found interaction of C99 with the C-terminal portion of MT5-MMP, the deletion of which caused a strong degradation of C99 by the proteasome, preventing Aβ accumulation. These findings reveal novel mechanisms for MT5-MMP control of APP metabolism and C99 fate involving proteolytic and non-proteolytic actions mainly mediated by the C-terminal part of the proteinase.
Competing Interest Statement
The authors have declared no competing interest.
Non-standard abbreviations
- 3xTg
- mouse model of Alzheimer’s disease expressing human APP, PSEN1 and MAPT genes with familial mutations
- 5xFAD
- mouse model of Alzheimer’s disease bearing 5 familial mutations on human APP and PSEN1
- Aβ
- amyloid beta peptide
- AD
- Alzheimer’s disease
- ADAM
- a disintegrin and metalloproteinase
- Aη-α
- APP fragment generated by η- and α-secretase
- APP
- amyloid beta precursor protein
- BACE
- β-secretase, beta-site APP cleaving enzyme 1
- C3
- BACE-1 inhibitor IV
- C99
- the last C-terminal 99 aminoacids of APP
- CAT
- catalytic
- CTF
- C-terminal fragment
- CTSD
- cathepsin D
- DAPT
- (2S)-N-[(3,5-Difluorophenyl)acetyl]-L-alanyl-2-phenyl]glycine 1,1-dimethylethyl ester, γ-secretase inhibitor
- EEA1
- early endosome marker
- FL
- full length
- GFP
- green fluorescent protein
- GI254023X
- specific ADAM10 inhibitor
- HEK
- human embryonic kidney cells
- HEKswe
- HEK carrying the familial Swedish APP mutation
- HPX
- hemopexin
- HRP
- horseradish peroxidase
- IB
- immunoblot
- IC
- intracytoplasmic
- IP
- immunoprecipitation
- iPS
- induced pluripotent stem cell
- LAMP1
- lysosome marker
- LTP
- long-term potentiation
- MG132
- D-Leucinamide, N-[(phenylmethoxy)carbonyl]-L-leucyl-N-[(1S)-1-formyl-3-methylbutyl]-, proteasome inhibitor
- MME
- membrane metallo-endopeptidase, neprilysin
- MMP
- matrix metalloproteinase
- MT5/1-MMP
- membrane-type 5/1-matrix metalloproteinase
- NCSTN
- nicastrin
- PSEN1/2
- presenilin 1/2
- PSENEN
- presenilin enhancer 2 homolog
- qPCR
- quantitative polymerase chain reaction
- RXPO3
- pseudophosphinic specific inhibitor of MMPs
- sAPP95
- soluble fragment of APP of 95 kDa
- sAPPα
- soluble fragment of APP generated by α-secretase
- TIMP-1/2
- tissue inhibitor of matrix metalloproteinase-1/2
- TM
- transmembrane