Imaging mass spectrometry analysis of XXXX biopsies reveals protein co-localization with amyloid deposits.

@entity12042 @entity5066 @entity2204 @entity2783 @entity1582 @entity5475 @entity4732
UNASSIGNED: @entity2783 is a heterogeneous group of protein misfolding diseases characterized by deposition of amyloid proteins. The kidney is frequently affected, especially by immunoglobulin light chain ( @entity1582 ) and @entity5475 ( @entity5475 ) @entity2783 as the most common subgroups. Current diagnosis relies on histopathological examination, Congo red staining, or electron microscopy. Subtyping is done by immunohistochemistry; however, commercially available antibodies lack specificity. The purpose of this study was to identify and map amyloid proteins in formalin-fixed paraffin-embedded tissue sections using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis in an integrated workflow. @entity12042 and @entity2783 biopsies were processed for histological and MS analysis. Mass spectra corresponding to the congophilic areas were directly linked to the histological and MS images for correlation studies. Peptides for @entity5475 and @entity1582 were detected by MALDI IMS associated to Congo red-positive areas. Sequence determination of amyloid peptides by LC-MS/MS analysis provided protein distribution and identification. Serum amyloid P component, @entity2204 , and @entity4732 proteins were identified in both @entity5066 and @entity1582 , showing a strong correlation with Congo red-positive regions. Our findings highlight the utility of MALDI IMS as a new method to type @entity2783 in histopathological routine material and characterize amyloid-associated proteins that may provide insights into the pathogenetic process of amyloid formation.
