Proteomic analysis of human nasal mucosa: different expression profile in rhino-pathologic states.

BACKGROUND: Rhinitis comprises several diseases with varying causes and different clinical manifestations and pathological features, but treated as a single clinical disorder. As heterogeneous disease, proper differential diagnosis is useful to delineate appropriate therapeutic intervention. Comparative proteomic investigation was aimed to provide information for specific differentially expressed proteins in rhino pathologic state, that could be used for diagnostic purpose and therapeutic monitoring. METHODS: Proteins extracted from nasal mucosa cells of patients with different features of rhinitis and from control subjects, were separated by 2-DE. Proteins differentially expressed were identified by mass spectrometry (MS). RESULTS: Comparative proteomic analyses led to the identification of eighteen proteins differentially expressed in patients with rhinitis, mainly related to cell defense and innate and acquired immunity. From that, at least one protein can be a possible candidate as biomarker of disease.

Intranasal administration of one alpha gliadin can downregulate the immune response to whole gliadin in mice.

The mucosal lesion present in coeliac disease is an immune-mediated injury triggered by gliadin and restricted by a particular assortment of major histocompatibility complex genes. In view of this, an immunomodulatory approach that induces tolerance to this antigen appears to be a possible alternative to a strict gluten-free diet in treating coeliac disease. We have shown that intranasal administration of multiple doses of whole gliadin is required to specifically inhibit T helper 1-like T-cell reactivity in BALB/c mice immunized parenterally with whole gliadin. However, T-cell activation to multiple antigens, as a consequence of the chemical complexity shown by the antigen gliadin, could hamper efforts to identify single component(s) useful for tolerance induction. In this study, gliadin fractions were purified and administered intranasally to study their ability to induce tolerance to whole gliadin in our animal model. We found that the alpha fraction was particularly effective in downregulating both the in vitro gliadin-specific T-cell proliferation and interferon-gamma production to whole gliadin. In particular, a purified alpha-gliadin was able to suppress the immune response to the entire gliadin mixture. These results demonstrate how an immune response to a complex antigen may be controlled by treatment with a purified component and specifically indicate alpha-gliadin to be a good candidate for further identification of short peptides to be used as tolerogens in this model.

The length of a single turn controls the overall folding rate of "three-fingered" snake toxins.

Snake curaremimetic toxins are short all-beta proteins, containing several disulfide bonds which largely contribute to their stability. The four disulfides present in snake toxins make a "disulfide beta-cross"-fold that was suggested to be a good protein folding template. Previous studies on the refolding of snake toxins (Ménez, A. et al. (1980) Biochemistry 19, 4166-4172) showed that this set of natural homologous proteins displays different rates of refolding. These studies suggested that the observed different rates could be correlated to the length of turn 2, one out of five turns present in the toxins structure and close to the "disulfide beta-cross". To demonstrate this hypothesis, we studied the refolding pathways and kinetics of two natural isotoxins, toxin alpha (Naja nigricollis) and erabutoxin b (Laticauda semifasciata), and two synthetic homologues, the alpha mutants, alpha60 and alpha62. These mutants were designed to probe the peculiar role of the turn 2 on the refolding process by deletion or insertion of one residue in the turn length that reproduced the natural heterogeneity at that locus. The refolding was studied by electrospray mass spectrometry (ESMS) time-course analysis. This analysis permitted both the identification and quantitation of the population of intermediates present during the process. All toxins were shown to share the same sequential scheme for disulfide bond formation despite large differences in their refolding rates. The results presented here demonstrate definitely that no residues except those forming turn 2 accounted for the observed differences in the refolding rate of toxins.