Mass spectrometry-based serum p Protein Profiling at population level: serum hapcidin and beyond

Iron is essential for multiple biological functions and its plasma levels have to be tightly regulated. Hepcidin, a peptide hormone produced by liver, is the main regulator of iron homeostasis and its altered production is related to functional iron deficiency (high hepcidin levels) or iron overload (hepcidin deficiency). The first part of the project here described is the quantification of serum hepcidin levels in the Val Borbera (VB) population, a genetic isolate living in Northern Italy, as part of a larger project started in 2005 for a demographic and epidemiological analysis. Serum hepcidin measurements were performed in our lab by a validated mass spectrometry-based method i.e. Surface-Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SELDI-TOF-MS). This technique allowed also the discrimination and quantification of a truncated hepcidin isoform, hepcidin-20, that has been studied for the first time at population level. In the second part of the project it is described the use of the SELDI platform for proteome profiling analysis, comparing spectra of subjects affected by iron disorders with those of healthy controls. Differentially expressed peptides, representing putative novel biomarkers have been further studied, as described in the third part of the work, both by classic proteomics (co-immunoprecipitation and Western blotting) and bioinformatics approaches, in order to confirm results and gain insight about the molecular pathway involved. The results of the projects here presented, like the establishment of a reference range for hepcidin-25 levels and the discovery of a putative novel biomarker of iron homeostasis diseases, could have clinical applications, both at diagnostic and therapeutic levels.