sodium-hypochlorite and thiazolidine-4-carboxylic-acid

Oxidative stress is associated with the pathophysiology of many degenerative human diseases, including Alzheimer's disease, atherosclerosis, Parkinson's disease, and cancers. We discovered in our previous study that thioproline (SPro), a proline analogue, is generated in oxidant-exposed cells. With the prior observation that SPro served as an efficient nitrile trapping agent, we tested in this study the hypothesis that this oxidative stress generated cysteine-formaldehyde adduct, SPro, may serve as an antioxidant protecting cells from oxidative stress. Interestingly, results showed that HeLa cells cultured in SPro-supplemented culture media are more tolerant of oxidative stress, indicated by a dosage-dependent increase in cell viability. Investigation of the molecular mechanism of the observed increase in cell tolerance to oxidative stress revealed SPro acting as an effective antioxidant by sacrificial oxidation. Results also showed that SPro had been incorporated into cellular proteins and induced changes in protein expression profiles of treated cells. Despite being yet to determine the participation of individual factors to the observed increase of cell tolerance to oxidative stress, this study sheds light on the potential use of SPro as a dietary supplement for protecting humans from oxidative stress-associated degenerative human diseases.

Topics: Antioxidants; Cell Survival; Edetic Acid; Ferrous Compounds; Glutathione; HeLa Cells; Humans; Hydrogen Peroxide; Oxidants; Oxidative Stress; Proteomics; Sodium Hypochlorite; Thiazolidines

Carcinogenic formaldehyde is produced by endogenous protein oxidation and various exogenous sources. With formaldehyde being both ubiquitous in the ambient environment and one of the most common reactive carbonyls produced from endogenous metabolism, quantifying formaldehyde exposure is an essential step in risk assessments. We present in this study an approach to assess the risk of exposure to oxidative stress by quantifying thiazolidine-4-carboxylic acid (TA), a cysteine-conjugated metabolite of formaldehyde in toxicant-exposed Escherichia coli. The method entails TA derivatization with ethyl chloroformate, addition of isotope-labeled TA derivatives as internal standards, solid-phase extraction of the derivatives, and quantification by liquid chromatography-mass spectrometry (LC-MS). After validating for accuracy and precision, the developed method was used to detect TA in oxidizing agent-exposed E. coli samples. Dose-dependent TA formation was observed in E. coli exposed to hydroxyl radical mediators Fe(2+)-EDTA, H2O2, and NaOCl, indicating the potential use of TA as a biomarker of exposure to oxidative stress and disease risk.

Topics: Chromatography, Liquid; Edetic Acid; Escherichia coli; Ferrous Compounds; Hydrogen Peroxide; Mass Spectrometry; Oxidative Stress; Sodium Hypochlorite; Thiazolidines