Abstract | PURPOSE: METHODS: Corneal amyloid deposits and the surrounding corneal stroma were procured by laser capture microdissection from a patient with an A546D mutation in TGFBI. Proteins in the captured corneal samples and healthy corneal stroma were identified with liquid chromatography-tandem mass spectrometry and quantified by calculating exponentially modified Protein Abundance Index values. Mass spectrometry data were further compared for identifying enriched regions of transforming growth factor beta induced protein (TGFBIp/ keratoepithelin/βig-h3) and detecting proteolytic cleavage sites in TGFBIp. RESULTS: CONCLUSIONS: Corneal amyloid caused by the A546D mutation in TGFBI involves several proteins associated with other varieties of amyloidosis. The proteomic data suggest that the sequence 571-YHIGDEILVSGGIGALVR-588 contains the amyloid core of the FAS1-4 domain of TGFBIp and point at serine protease HtrA1 as the most likely candidate responsible for the proteolytic processing of amyloidogenic and aggregated TGFBIp, which explains the accumulation of HtrA1 in the amyloid deposits. With relevance to identifying serine proteases, we also found glia-derived nexin (protease-nexin 1) in the amyloid deposits, making this serine protease inhibitor a good candidate for the physiologically relevant inhibitor of one of the amyloid-associated serine proteases in the cornea and probably in other tissues. Noteworthy, the present results are in accordance with our findings from a previous study of corneal amyloid deposits caused by the V624M mutation in TGFBI, suggesting a common mechanism for lattice corneal dystrophies (LCDs) associated with mutations in the TGFBIp FAS1-4 domain.
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Authors | Henrik Karring, Ebbe Toftgaard Poulsen, Kasper Runager, Ida B Thøgersen, Gordon K Klintworth, Peter Højrup, Jan J Enghild |
Journal | Molecular vision
(Mol Vis)
Vol. 19
Pg. 861-76
( 2013)
ISSN: 1090-0535 [Electronic] United States |
PMID | 23592924
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- Extracellular Matrix Proteins
- Protease Inhibitors
- Transforming Growth Factor beta
- betaIG-H3 protein
- High-Temperature Requirement A Serine Peptidase 1
- HtrA1 protein, human
- Serine Endopeptidases
- Trypsin
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Topics |
- Aged
- Amino Acid Sequence
- Cluster Analysis
- Cornea
(metabolism, pathology)
- Corneal Dystrophies, Hereditary
(metabolism, pathology)
- Corneal Stroma
(metabolism, pathology)
- Extracellular Matrix Proteins
(chemistry, metabolism)
- Female
- High-Temperature Requirement A Serine Peptidase 1
- Humans
- Microdissection
- Molecular Sequence Data
- Plaque, Amyloid
(metabolism)
- Protease Inhibitors
(metabolism)
- Protein Structure, Tertiary
- Proteolysis
- Proteomics
- Sequence Alignment
- Serine Endopeptidases
(metabolism)
- Tandem Mass Spectrometry
- Transforming Growth Factor beta
(chemistry, metabolism)
- Trypsin
(metabolism)
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