-
[show abstract]
[hide abstract]
ABSTRACT: In Transthyretin amyloidosis (ATTR), tissue deposition of transthyretin fibrils translates into a significant subversion of the tissues proteome. We used multidimensional protein identification technology for profiling the proteome of subcutaneous adipose tissue in patients with ATTR, in comparison with controls and patients with other types of amyloidoses, to identify the global proteomic changes related specifically with this disease. The adipose tissue proteome of five ATTR patients and 11 non-affected controls was analyzed. Samples from patients with Light Chain (AL) or reactive (AA) amyloidosis were studied alongside. In all ATTR samples, mass spectrometry data showed that transthyretin was specifically up-represented, being a marker of the nature of the deposits. Tissue resident proteins, involved in key biological processes, were also found to be differently represented compared to controls. The high-throughput analysis of the proteome of amyloid affected fat, combined with bioinformatic data interpretation, is a powerful tool for identification of perturbed protein expression in ATTR amyloidosis.
Amyloid: the international journal of experimental and clinical investigation: the official journal of the International Society of Amyloidosis 05/2012; 19 Suppl 1:11-3. · 2.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Considering the important advances in treating specific types of systemic amyloidoses, unequivocal typing of amyloid deposits is now essential. Subcutaneous abdominal fat aspiration is the easiest, most common diagnostic procedure. We developed a novel, automated approach, based on Multidimensional Protein Identification Technology, for typing amyloidosis. Fat aspirates were obtained from patients with the most common systemic amyloidoses (ALλ, ALκ, transthyretin, and reactive amyloidosis), with Congo red score more than or equal to 3+, and nonaffected controls. Peptides from extracted and digested proteins were analyzed by Multidimensional Protein Identification Technology. On semiquantitative differential analysis (patients vs controls) of mass spectrometry data, specific proteins up-represented in patients were identified and used as deposit biomarkers. An algorithm was developed to classify patients according to type and abundance of amyloidogenic proteins in samples; in all cases, proteomic characterization was concordant with fibril identification by immunoelectron microscopy and consistent with clinical presentation. Our approach allows reliable amyloid classification using readily available fat aspirates.
Blood 09/2011; 119(8):1844-7. · 9.90 Impact Factor
-
Francesca Lavatelli,
Francesca Brambilla, Veronica Valentini,
Paola Rognoni,
Simona Casarini,
Dario Di Silvestre,
Vittorio Perfetti,
Giovanni Palladini,
Gabriele Sarais,
Pierluigi Mauri,
Giampaolo Merlini
[show abstract]
[hide abstract]
ABSTRACT: An excess of circulating monoclonal free immunoglobulin light chains (FLC) is common in plasma cell disorders. A subset of FLC, as amyloidogenic ones, possess intrinsic pathogenicity. Because of their complex purification, little is known on the biochemical features of serum FLC, possibly related to their pathogenic spectrum. We developed an immunopurification approach to isolate serum FLC from patients with monoclonal gammopathies, followed by proteomic characterization. Serum monoclonal FLC were detected and quantified by immunofixation and immunonephelometry. Immunoprecipitation was performed by serum incubation with agarose beads covalently linked to polyclonal anti-κ or λ FLC antibodies. Isolated FLC were analyzed by SDS-PAGE, 2D-PAGE, immunoblotting, mass spectrometry (MS). Serum FLC were immunoprecipitated from 15 patients with ALλ amyloidosis (serum λ FLC range: 98-2350mg/L), 5 with ALκ amyloidosis and 1 with κ light chain (LC) myeloma (κ FLC range: 266-2660mg/L), and 3 controls. Monoclonal FLC were the prevalent eluted species in patients. On 2D-PAGE, both λ and κ FLC originated discrete spots with multiple pI isoforms. The nature of eluted FLC and coincidence with the LC sequence from the bone marrow clone was confirmed by MS, which also detected post-translational modifications, including truncation, tryptophan oxidation, cysteinylation, peptide dimerization. Serum FLC were purified in soluble form and adequate amounts for proteomics, which allowed studying primary sequence and detecting post-translational modifications. This method is a novel instrument for studying the molecular bases of FLC pathogenicity, allowing for the first time the punctual biochemical description of the circulating forms.
Biochimica et Biophysica Acta 03/2011; 1814(3):409-19. · 4.66 Impact Factor
