Immunoproteomics of myasthenia

Autoantibodies to nAChR are found in 85% of patients with Myasthenia Gravis (seropositive) while in 15% of them the standard immunoprecipitation test for anti-AChR is negative (seronegative). Some of these seronegative patients have antibodies against muscle specific Kinase ( MuSK). The aim of this study is to try to define auto-antibodies against protein different from AChR and MuSK in seronegative patients. We used the cell line TE671, that expresses human AChR. Through our proteomic approach we identified some proteins that could represent potential antigens different from AChR and MuSK

Strain difference in protein expression in lungs of mice after cigarette smoke exposure

Cigarette smoke (CS) is the most prominent factor determining the increased prevalence of the emphysema. However, little is known why only a susceptible minority (8% – 16%) of heavy tobacco smokers develop a clinically significant disease. This suggests that genetic factors may modulate each individual’s risk. We recently reported strain differences in the response to CS in mice characterized by different levels of serum alpha1-proteinase inhibitor and sensitivity to oxidants. When exposed to CS, C57Bl and DBA/2 mice develop emphysema, while ICR mice do not show any parenchymal changes. In order to have some information on individual factors underlying this suscep- tibility, we examined the global change of lung protein expression in response to CS in these strains. With a classical proteomic approach, 2D electrophoresis and mass spectrometry, several proteins have been found significantly up- and down-regulated in the different strains of mice. In particular, we identified 6 up-regulated and 8 down-regulated proteins in C57Bl mice as well as 4 up- regulated and 6 down-regulated proteins in DBA/2 mice. On the other hand, in insensitive ICR mice we found only down-regulated proteins. These proteins belong to cytoskeleton proteins or various functional protein groups involved in antioxidant and detoxification processes, glucose metabolism or stress response. The distribution of some of these proteins in the lung has been analysed by immunohistochemistry. A series of qualitative and quantitative protein variations have been found among mouse strains with a different susceptibility to develop smoke-induced pulmonary lesion

Serum albumin fragmentation in end-stage renal disease patients - a pilot study

BACKGROUND: The goal of this study was to detect modification in the expression of plasma proteins and/or post-translational modifications of their structure in patients with end stage renal disease. METHODS: Serum samples from 19 adult patients treated by maintenance hemodialysis (MHD) were analyzed in comparison to sera from six healthy controls using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2DE). Spots of interest were identified by mass spectrometry analysis. In addition, the 2DE maps were incubated with a human anti-albumin polyclonal antibody. RESULTS: SDS-PAGE gels, 2DE maps and matrix-assisted laser desorption/ionization time of flight analysis indicated over-expression of low-molecular weight proteins (LMWP) in sera from patients. Unexpectedly, another 15 spots with estimated M(r) of 12.5-29 kDa from the 2DE maps of six patients were identified as fragments of albumin. 2D immunoblotting of sera from 12 other patients detected numerous albumin fragments. CONCLUSIONS: These results indicate that in addition to increased expression of LMWP, a relevant amount of albumin fragments are detectable in the serum of patients undergoing MHD. Uremia appears to facilitate the fragmentation of albumin and/or the retention of albumin fragments in blood