Proteomics in Ménière disease.

Ménière's disease (MD) is a disorder of the inner ear characterized by an insidious onset and aspecific symptoms, such as dizziness, vertigo, tinnitus, and hearing loss, that may become very debilitating. The presence of endolymphatic hydrops is a common feature in MD patients, but the pathophysiology is still largely unknown. In this study, we have used a proteomics-driven approach to identify potential biomarkers of MD. To this end, plasma was obtained from whole blood of 16 individuals previously diagnosed as suffering from MD and compared to plasma from healthy donors. A depletion of the highly abundant proteins (i.e., albumin, IgG, transferrin, etc.) was performed in order to enhance the chance of detection of the less represented ones, therefore reducing the noise-background. Two-dimensional gel electrophoresis, followed by in-gel tryptic digestion of the selected spots and LC-MS/MS analysis, allowed us to identify a set of proteins whose expression appears to be differentially modulated in patients versus controls. In particular: complement factor H and B, fibrinogen alpha and gamma chains, beta-actin and pigment epithelium derived factor are over expressed; on the other hand, the levels of beta-2 glycoprotein-1, vitamin D binding protein and apolipoprotein-1 are significantly decreased in the plasma of MD-affected individuals. Even though preliminary and not necessarily linked directly to the molecular pathogenesis of the disease, our original findings suggest that a molecular signature, represented by the plasma protein profile previously described, might represent a potentially powerful, innovative and not invasive tool for early diagnosis and clinical management of MD patients. J. Cell. Physiol. 227: 308-312, 2012. © 2011 Wiley Periodicals, Inc.

Assessment of an ad hoc procedure for isolation and characterization of human albuminome.

The dynamic range of plasma protein abundance, ranging from milligrams to picograms per milliliter, makes characterization of this proteome nearly impossible with current analytical methods. Plasma preprocessing by high-abundance protein depletion may concomitantly remove important diagnostic information. This article describes an original chromatographic procedure to isolate proteins bound to human serum albumin (HSA). Using HSA as an "affinity agent", we significantly improved the detection and identification of HSA ligands by two-dimensional liquid chromatography tandem mass spectrometry (2D LC-MS/MS). Some of the characterized species were not previously reported in published blood databases. Albumin-binding proteins may be classified as belonging to several putative functional categories and span a wide variety of predicted physiological functions.