Conti M, Poppi I, Cavedagna TM, Zamagni E, Leone O, Corti B, Milandri A, Bacci F, Ramazzotti E, Mancini R, Cavo M, Quarta CC, Rapezzi C. A targeted proteomics approach to amyloidosis typing.
CLINICAL MASS SPECTROMETRY (DEL MAR, CALIF.) 2018;
7:18-28. [PMID:
39193554 PMCID:
PMC11322773 DOI:
10.1016/j.clinms.2018.02.001]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 01/11/2023]
Abstract
Background
Amyloidosis is a life threatening disease caused by deposition of various types of blood serum proteins in organs and tissues. Knowing the type of protein involved is the basis of a correct diagnosis and personalized medical treatment. While the classical approach uses immunohistochemistry, in recent years, laser micro-dissection, followed by high resolution LC-MS/MS, has been shown to provide superior diagnostic sensitivity and specificity. This techniques, however, is only available at major reference proteomics centers.
Objective
To perform clinical amyloid protein typing using low-resolution mass spectrometry and no laser micro dissection (LMD), we developed a targeted proteomics approach for the determination of both frequently encountered amyloid proteins (i.e., κ and -λ immunoglobulin light chains and transthyretin (TTR)) and specific reference proteins (i.e., actin (A) for cardiac muscle tissue, or fatty acid binding protein 4 (FBP4) for subcutaneous adipose tissue) in histologic specimens.
Method
Small tissue fragments and/or histological sections were digested to yield a protein mixture that was subsequently reduced, alkylated and trypsinized to obtain a peptide mixture. After SPE purification and LC separation, proteotypic peptides were detected by their MRM transitions.
Results
The method showed high specificity and sensitivity for amyloid protein proteotypic peptides. LODs were 1.0, 0.1, 0.2 picomoles in cardiac muscle tissue (CMT) and 0.1, 0.2, 0.5 picomoles in subcutaneous adipose tissue (SAT) for TTR, κ-, and λ-LC proteins, respectively. Amyloid to tissue-specific protein signal ratios correlated with the presence of amyloid deposits in clinical samples.
Conclusions
This targeted proteomics approach enables sensitive and specific discrimination of amyloidosis affected tissues for the purpose of clinical research.
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