Protein Damage by Reactive Electrophiles: Targets and Consequences

Abstract

It has been 60 years since the Millers first described the covalent binding of carcinogens to tissue proteins. Protein covalent binding was gradually overshadowed by the emergence of DNA adduct formation as the dominant paradigm in chemical carcinogenesis but re-emerged in the early 1970s as a critical mechanism of drug and chemical toxicity. Technology limitations hampered the characterization of protein adducts until the emergence of mass spectrometry-based proteomics in the late 1990s. The time since then has seen rapid progress in the characterization of the protein targets of electrophiles and the consequences of protein damage. Recent integration of novel affinity chemistries for electrophile probes, shotgun proteomics methods, and systems modeling tools has led to the identification of hundreds of protein targets of electrophiles in mammalian systems. The technology now exists to map the targets of damage to critical components of signaling pathways and metabolic networks and to understand mechanisms of damage at a systems level. The implementation of sensitive, specific analyses for protein adducts from both xenobiotic-derived and endogenous electrophiles offers a means to link protein damage to clinically relevant health effects of both chemical exposures and disease processes.

Synthesis, cellular evaluation, and mechanism of action of piperlongumine analogs

“…Taken together, our observations suggest that elevation of protein glutathionylation or other cellular cross-linking events may be a feature of cells treated with PL more closely associated with cellular toxicity than elevation of ROS or glutathione depletion. Further proteomic analyses will be required to identify specific protein glutathionylation events and proteins that interact with analogs of markedly enhanced (PL-DI, PL-TRI) or diminished (PL-H 2 ) electrophilicity and toxicity (31). These studies establish a central role for multivalent electrophilicity in the chemical biology of PL and related compounds, and indicate that both electrophilic and oxidative stress phenotypes can contribute to PL's promising cancer-selective toxicity.…”

Nrf2-dependent and -independent Responses to Nitro-fatty Acids in Human Endothelial Cells

“…Nitroalkenes are notable because the vinyl nitro group confers a kinetically rapid and reversible electrophilic reactivity that induces the post-translational modification of susceptible proteins, principally via S-alkylation of thiols (35). Current data support that cell survival and anti-inflammatory responses, rather than dysmetabolic and genotoxic events, are predominantly evoked by low concentrations of electrophiles (36). Here, genome-wide transcriptional profiling was utilized to identify specific gene regulatory pathways that mediate vascular endothelial responses to nitroalkenes.…”

Chemistry and analysis of HNE and other prominent carbonyl-containing lipid oxidation compounds

“…One way to overcome this issue is to apply enrichment tools to bottom-up LC-MS approaches, which can lead significantly increase the sensitivity and specificity [120]. The most common principle is to use a biotin hydrazide to label protein carbonyls and then enrich these proteins by avidin capture on a solid phase.…”