title: Characterisation of serum transthyretin by electrospray ionisation-ion mobility mass spectrometry: Application to familial amyloidotic polyneuropathy type I (FAP-I).
abstract: Transthyretin (TTR) is a homotetrameric protein which is known to misfold and aggregate causing different types of amyloidosis, such as familial amyloidotic polyneuropathy type I (FAP-I). FAP-I is associated with a specific TTR mutant variant (TTR (Met30)) that can be easily detected analysing the monomeric forms of the mutant protein. Meanwhile, the mechanism of protein aggregation onset, which could be triggered by structural changes on the native tetrameric protein complex, remains uncertain. We developed and described herein a new sample pretreatment based on immunoprecipitation (IP) to purify TTR from serum under non-denaturing conditions. Later, a nano-electrospray ionization-ion mobility mass spectrometry (nano-ESI-IM-MS or IM-MS) method was optimised to analyse the protein complexes in serum samples from healthy controls and FAP-I patients. IM-MS allowed separation and characterisation of tetrameric, trimeric and dimeric TTR gas ions due to their differential drift time, which is related to ion size and charge. The tetramer-to-dimer abundance ratio was differential between healthy controls and FAP-I patients (asymptomatic, symptomatic and an iatrogenic patient originally without the mutation who received a liver transplant from an FAP-I patient), and was also indicative of the effectiveness of liver transplantation as a treatment for FAP-I.
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Pont
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain. Electronic address: fbenavente@ub.edu.
authors.forename: Fernando
authors.initials: F
authors.lastname: Benavente
authors.affiliation: Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Vilaseca
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.
authors.forename: Estela
authors.initials: E
authors.lastname: Giménez
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Sanz-Nebot
mesh_terms: D028227:Amyloid Neuropathies, Familial / Q000097:blood*; D001774:Blood Chemical Analysis / Q000379:methods*; D006801:Humans; D011228:Prealbumin / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D011228:Prealbumin
keywords: Familial amyloidotic polyneuropathy; Ion mobility; Mass spectrometry; Native immunoprecipitation; Neurodegeneration; Protein–protein