Utility and Limitations of the Methyl Diaminobenzene-BODIPY Fluorescent Biosensor for Detecting Methylglyoxal in Cells.

Methylglyoxal (MG) is a small and highly reactive byproduct of multiple metabolic reactions. In mammalian cells, MG serves important roles in cell signaling, but elevated levels of MG are toxic and contribute to the progression of many diseases, including autoimmune conditions and cancer. The study of MG is hampered by the lack of simple, accurate, and well-validated detection techniques. Here, we evaluate the previously reported methyl diaminobenzene-BODIPY (MBo) fluorescent probe by testing the detection of MG in solution, cell lysates, and live cells, using both plate reader and flow cytometry methods. We show that the MBo probe detects MG with a low nanomolar limit of detection in PBS and can quantitate low micromolar variations in MG abundance in both live cells and in lysed end point cellular assays. Our results highlight considerations for the use of MBo in common assays, including background assessments when using culture media containing serum, differential sensitivity with a range of lysis buffers, effects of fixation in flow cytometric assays, and depletion of residual MG in tissue culture media. Overall, this study establishes a framework using MBo to accurately assess MG in cellular systems.