Lipidomics Reveals Similar Changes in Serum Phospholipid Signatures of Overweight and Obese Pediatric Subjects.

Obesity is a public health problem and a risk factor for pathologies such type 2 diabetes mellitus, cardiovascular diseases, and nonalcoholic fatty liver disease. Given these clinical implications, there is a growing interest to understand the pathophysiological mechanism of obesity. Changes in lipid metabolism have been associated with obesity and obesity-related complications. However, changes in the lipid profile of obese children have been overlooked. In the present work, we analyzed the serum phospholipidome of overweight and obese children by HILIC-MS/MS and GC-MS. Using this approach, we have identified 165 lipid species belonging to the classes PC, PE, PS, PG, PI, LPC, and SM. The phospholipidome of overweight (OW) and obese (OB) children was significantly different from normal-weight children (control). Main differences were observed in the PI class that was less abundant in OW and OB children and some PS, PE, SM, and PC lipid species are upregulated in obese and overweight children. Although further studies are needed to clarify some association between phospholipid alterations and metabolic changes, our results highlight the alteration that occurs in the serum phospholipid profile in obesity in children.

Proteomic profile of susceptible and multidrug-resistant clinical isolates of Escherichia coli and Klebsiella pneumoniae using label-free and immunoproteomic strategies.

Infectious diseases caused by multidrug-resistant (MDR) Enterobacteriaceae have exponentially increased in the past decade, and are a major concern in hospitals. In the first part of the work, we compared the proteome profile of MDR and susceptible clinical isolates of Escherichia coli and Klebsiella pneumoniae in order to identify possible biological processes associated with drug resistance and susceptible phenotypes, using a label-free approach. In the second part, we used an immunoproteomics approach to identify immunoreactive proteins in the same isolates. A total of 388 and 377 proteins were identified in MDR and susceptible E. coli, respectively, evidencing that biological processes related to translation are upregulated in E. coli MDR, while there is an upregulation of processes related to catalytic activity in K. pneumoniae MDR. Both MDR strains show downregulation of processes related to amino acid activation and tRNA amino-acylation. Our data also suggest that MDR strains have higher immunoreactivity than the susceptible strains. The application of high-throughput mass spectrometry (MS) and bioinformatics to the study of modulation of biological processes might shed light on the characterization of multidrug resistance in bacteria.

New Insights on the Impact of Statin Therapy in the Susceptibility to Hypovitaminosis D Through Serum Lipidome Profiling.

Hypovitaminosis D is a worldwide clinical problem, affecting populations in numerous ways. Several factors seem to affect vitamin D metabolism, including the suggestion that therapy with the lipid lowering HMG-CoA inhibitors might modulate vitamin D levels. However, the relationship between statins intake and serum levels of vitamin D is still controversial. The present work aimed to add new insights on the association between statins therapy, and more specifically the generation of statins, and the lipid profile in a population of 106 subjects treated with these HMG-CoA inhibitors. Data showed that despite a higher prevalence of hipovitaminosis D in subjects treated with statins, there is no association between statin generation, total and LDL cholesterol and vitamin D levels. Moreover, second generation statins, the most common treatment of hypercholesterolemia in the studied population, promoted the remodelling of serum fatty acids that was characterized by the increase of arachidonic acid (AA) relative levels without affecting eicosapentaenoic acid (EPA) levels. Among statin treated subjects, vitamin D levels did not affect serum fatty acid profile. The statin-related increased ratio AA/EPA suggests a pro- inflammatory status, whose long-term impact should be better clarified in the future.

Immunoreactive pattern of Staphylococcus epidermidis biofilm against human whole saliva.

Saliva is essential to interact with microorganisms in the oral cavity. Therefore, the interest in saliva antimicrobial properties is on the rise. Here, we used an immunoproteomic approach, based on protein separation of Staphylococcus epidermidis biofilms by 2DE, followed by Western-blotting, to compare human serum and saliva reactivity profile. A total of 17 proteins were identified by MALDI-TOF/TOF. Serum and saliva presented a distinct pattern of immunoreactive proteins. Our results suggest that saliva seems to have higher propensity to react against S. epidermidis proteins with oxidoreductase activity and proteins involved with L-serine metabolic processes. We show that saliva was a powerful tool for the identification of potential S. epidermidis biofilms proteins.

An immunoproteomic approach for characterization of dormancy within Staphylococcus epidermidis biofilms.

Virulence of Staphylococcus epidermidis is mainly attributed to surface colonization and biofilm formation in indwelling medical devices. Physiological heterogeneity of biofilms may influence host immune response and sensitivity to antibiotics. Dormant cells, among others, contribute to biofilm heterogeneity. The aim of this study was to identify immunogenic proteins of S. epidermidis biofilms associated with dormancy mechanism, by using two-dimensional electrophoresis (2-DE) immunoblotting and mass spectrometry (MS). A total of 19 bacterial proteins, recognized by human serum samples, were identified. These proteins were mainly involved in small molecule metabolic biological processes. Catalytic activity and ion binding were the most representative molecular functions. CodY and GpmA proteins were more reactive to sera when biofilm dormancy was induced, while FtnA and ClpP were more reactive when dormancy was prevented. This is the first work that identifies differences in immunoreactive proteins within bacterial biofilms with induced or prevented dormancy. Considering the importance of dormancy within biofilms, further evaluation of these proteins can provide insights into the mechanisms related to dormancy and help to improve current understanding on how dormancy affects the host immune response.