Within the wide range of oxidative modifications, "carbonylation" formed by the incorporation of aldehyde/keto groups, is commonly studied due to its role in cell physiology and as prospective biomarkers for numerous disorders. Despite close biochemical and physiological links between protein and lipid carbonylation, these two types of modifications are rarely addressed simultaneously in a single study. In nitrosative stress cell model we investigated levels of protein and lipid carbonylation and addressed the main modified species by combining LC-MS, biochemical, and microscopy studies. The influence of nitrosative stress on carbonylation of proteins and lipids was investigated for primary cardiomyocytes treated with SIN-1 for different time intervals. Lipid carbonylation was quantified by RPC-ESI-MS/MS. The results demonstrate dynamic generation, degradation and adduct formations of 25 different species including alkanals, alkenals, alkadienals, alkatrienals and oxo-carboxylic acids. Several new PL-bound aldehydes were present exclusively after a long incubation period. Carbonylated proteins were identified after aldehyde reactive probe derivatization, affinity enrichment and RPC-ESI-MS/MS. More than 200 proteins were identified and evaluated by systems biology to deduce the biological significance of the protein modifications. The protein carbonylation degree was verified using oxyblot and correlated with changes in 20S/26S proteasome activities. Furthermore, a new fluorescence microscopy based technique to stain carbonylated biomolecules was developed and compared with conventional DNPH-based immunocytochemistry. Subcellular localization of carbonylated species was investigated using mitochondrial and ER-specific co-localization experiments. Thus, the combination of lipidomics, proteomics, biochemical techniques, and microscopy imaging revealed a complex molecular pattern of "carbonylation stress" in the studied nitrosative stress cell model.
Copyright © 2014. Published by Elsevier Inc.