We have previously described that, in healthy human skeletal muscle, an anti-histidine-proline-rich-glycoprotein (HPRG) antibody selectively binds to type IIB fibers that are well known to contain the highest level of AMP deaminase (AMPD) activity, suggesting an association of the HPRG-like protein to the enzyme isoform M. The present paper reports an immunohistochemical study performed on human skeletal muscle biopsies from patients with AMPD deficiency and carried out utilizing both the anti-HPRG antibody and an anti-AMPD antibody specific for the isoform M. A correlation between the muscle content of the HPRG-like protein and the level of AMPD activity was demonstrated. In the specimens from patients with Acquired AMPD deficiency the HPRG-immunoreactivity was less intense than that shown by the control subjects and was related to the residual AMPD activity. The patients affected by Primary and Coincidental AMPD deficiency, which were characterized by an absence of enzyme activity and AMPD immunoreactivity, showed the lowest HPRG immunoreactivity that was clearly detectable by Western blot analysis, but not by immunohistochemistry. The interpretation of the significance of these observations suggests a physiological mutual dependence between skeletal muscle HPRG and AMPD polypeptides with regard to their stability

Background This proof of concept study was aimed at characterizing novel salivary biomarkers specific for different subsets in primary Sjögren’s syndrome (pSS) in order to improve patients’ profiling. Methods pSS patients were stratified in three subgroups according to both (a) focus score in the minor salivary gland biopsies (i.e. intensity of immune cell infiltration in the tissue) and (b) unstimulated salivary flow rate. Healthy volunteers were included as controls. A nano-HPLC-SWATH-MS approach was used for the analysis of saliva proteome of different subsets. Results We found 203 differentially expressed proteins in pSS patients with respect to controls with evident differences in the expression of normal constituents of the human salivary proteome (i.e. prolactin-inducible protein, proline-rich proteins, cystatins) and several mediators of inflammatory processes. The comparative analysis of the pSS phenotypes unrevealed 63 proteins that were shared and specifically modulated in the three subsets of pSS patients converging on several inflammatory pathways. Among them S100A protein appeared of particular interest merging on IL-12 signaling and being significantly influenced by either salivary flow impairment or intensity of immune cell infiltration in the tissue. Conclusions Constellations of proteins, including S100A proteins, characterize different pSS subsets reflecting either salivary gland dysfunction or inflammation. Salivary proteomics may foster future research projects ultimately aimed at developing personalized treatments for pSS patients. Electronic supplementary material The online version of this article (10.1186/s12014-019-9245-1) contains supplementary material, which is available to authorized users.

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Cystatin S emerged as a promising biomarker for pSS, strongly correlated with glandular dysfunction. An upregulation of miR-126 and miR-335-5P might be implicated in its expression.

Cardiac connexins (Cxs) are proteins responsible for proper heart function. They form gap junctions that mediate electrical and chemical signalling throughout the cardiac system, and thus enable a synchronized contraction. Connexins can also individually participate in many signal transduction pathways, interacting with intracellular proteins at various cellular compartments. Altered connexin expression and localization have been described in diseased myocardium and the aim of this study is to assess the involvement of Cx43, Cx26, and some related molecules in ponatinib-induced cardiac toxicity. Ponatinib is a new multi-tyrosine kinase inhibitor that has been successfully used against human malignancies, but its cardiotoxicity remains worrisome. Therefore, understanding its signaling mechanism is important to adopt potential anti cardiac damage strategies. Our experiments were performed on hearts from male and female mice treated with ponatinib and with ponatinib plus siRNA-Notch1 by using immunofluorescence, Western blotting, and proteomic analyses. The altered cardiac function and the change in Cxs expression observed in mice after ponatinib treatment, were results dependent on the Notch1 pathway and sex. Females showed a lower susceptibility to ponatinib than males. The downmodulation of cardiac Cx43, Cx26 and miR-122, high pS368-Cx43 phosphorylation, cell viability and survival activation could represent some of the female adaptative/compensatory reactions to ponatinib cardiotoxicity.