Biomarkers are characteristics that could be measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. Complex organ function or cognizable changes in molecular level can be used as biomarkers. Natural diseases and exposing to toxicants or specific environments may lead to fatal alteration of the biological system of a subject. Detecting alterations in the early stage, diseases could be treated appropriate. As a consequence, the evaluation of health status is extremely useful in health care and medication. Biomarkers are extremely useful in both toxicological research as well as biological monitoring.

Oxidative stress is related to the process of aging and many kinds of chronic disea...[ Read more ]

Biomarkers are characteristics that could be measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. Complex organ function or cognizable changes in molecular level can be used as biomarkers. Natural diseases and exposing to toxicants or specific environments may lead to fatal alteration of the biological system of a subject. Detecting alterations in the early stage, diseases could be treated appropriate. As a consequence, the evaluation of health status is extremely useful in health care and medication. Biomarkers are extremely useful in both toxicological research as well as biological monitoring.

Oxidative stress is related to the process of aging and many kinds of chronic diseases. It was caused by the accumulation of reactive oxygen/nitrogen species (ROS/RNS) broke the imbalance between oxidants and antioxidants. Excess ROS/RNS will attack bimolecular and generate formaldehyde in vivo. With formaldehyde being both ubiquitous in the ambient environment and one of the most common reactive carbonyls produced from endogenous metabolism, quantitating formaldehyde exposure is thus an essential way to risk assessments. The goal of my first project is to develop thioproline (thiazolidine-4-carboxylic acid, TA), a cysteine-conjugated metabolite of formaldehyde as a biomarker for assessing the risk of oxidative stress and formaldehyde exposures. Dose-dependent formation of TA was observed in the cultured resuspension solution of Escherichia coli (E. coli) exposed to hydroxyl radical mediators of Fe²⁺-EDTA, H₂O₂, and NaOCl, indicating the potential use of TA as biomarker of exposure to oxidative stress and disease risk.

Formaldehyde may also reacted with amino acid residues in protein leading to post-translational modifications (PTMs) to proteins which have been well-documented to play important roles in normal cell physiology such as cell signaling and protein functions. PTMs have also been demonstrated to be one of the milestones in the pathophysiology of many human diseases such as cancer, age-related pathology, and neurodegenerative disorders. The goal of my second project is to identify of a novel PTM, 'thiazolidination', formed by reacting formaldehyde with cysteine residue in protein. The study was performed by quantitating thioproline in protein in formaldehyde- and oxidant-exposed E. coli. Further, N⁶-formyllysine, a well-defined formylation product formed by reacting formaldehyde with lysine, was exploited in a comparative study to evaluate the relative reactivity and amount of thiazolidination in the protein formylation chemistry. It is feasible that 'thiazolidination' may serve a biomarker for oxidative stress exposure and with the potential of filling one of the gaps in mining for unknown/novel PTMs in protein.