Proteomics analysis of amyloid corneal aggregates from lattice corneal dystrophy patients

ABSTRACT: TGFBI associated Corneal Dystrophies (CD) are a group of inherited protein folding disorders linked to the mutation in the TGFBI gene. The resultant mutant protein (TGFBIp) is deposited as insoluble protein aggregates in various layers of the cornea leading to corneal opacity and poor vision. Depending on the type of mutation the deposits may be classified as amyloid fibrillar type, amorphous globular aggregates or a mixed form of both fibrils and amorphous aggregates. However, the molecular mechanism of the mutant-induced amyloidosis is not fully understood. This study aimsto characterize truncated peptides enriched in the amyloid aggregates and to identify the protein composition of the corneal aggregates derived from dystrophic patients using LC-MS/MS and compare the data with normal control cornea. We have identified several amyloid associated proteins, non-fibrillar amyloid associated proteins and TGFBIp as the major component of the corneal deposits. The results suggest that Apolipoprotein A-IV, Apolipoprotein E and Serine protease HtrA1 to be significantly enriched in the corneal deposits compared to the normal cornea. Comparative analysis of peptides from corneal deposits of patient and control identified several peptides of TGFBIp which are enriched in patient tissue and may form the core of corneal amyloids. Most of the peptides represent the 4th FAS-1 domain of the protein. Biophysical studies of two such peptides (G515DNRFSMLVAAIQSAGLTETLNR533 and Y571HIGDEILVSGGIGALVR588) demonstrate that they readily form amyloid fibrils under physiological conditions, confirming their intrinsic propensity to form amyloid fibrils. The identification of proteins which are involved in other protein misfolding disorders as well as identification of peptides from TGFBIp which form -amyloid core highlight that the mechanism of amyloid formation may share common molecular pathways.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Eye

DISEASE(S): Lattice Corneal Dystrophy

SUBMITTER: Bamaprasad Dutta  

LAB HEAD: Siu Kwan SZE

PROVIDER: PXD006640 | Pride | 2022-02-28

REPOSITORIES: Pride