Thiosulfate sulfurtransferase prevents hyperglycemic damage to the zebrafish pronephros in an experimental model for diabetes

Identification and characterization of a small molecule that activates thiosulfate sulfurtransferase and stimulates mitochondrial respiration

The enzyme Thiosulfate sulfurtransferase (TST, EC 2.8.1.1), is a positive genetic predictor of diabetes type 2 and obesity. As increased TST activity protects against the development of diabetic symptoms in mice, an activating compound for TST may provide therapeutic benefits in diabetes and obesity. We identified a small molecule activator of human TST through screening of an inhouse small molecule library. Kinetic studies in vitro suggest that two distinct isomers of the compound are required for full activation as well as an allosteric mode of activation. Additionally, we studied the effect of TST protein and the activator on TST activity through mitochondrial respiration. Molecular docking and molecular dynamics (MD) approaches supports an allosteric site for the binding of the activator, which is supported by the lack of activation in the Escherichia coli. mercaptopyruvate sulfurtransferase. Finally, we show that increasing TST activity in isolated mitochondria increases mitochondrial oxygen consumption.

Using proteomics, q-PCR and biochemical methods complementing as a multiapproach to elicit the crucial responses of zebrafish liver exposed to neonicotinoid pesticide

Pesticides enter the environment through runoff and leaching and this raises public concern about effects on non-target organisms. Imidacloprid (IMI) a synthetic pesticide, has an unstable half-life, metabolized in minutes to weeks in the water. To evaluate the effects of IMI on the zebrafish liver, we conducted proteomic, molecular and biochemical analysis in a multi-level approach, to highlight the complementary features regarding the results of each method. Adult zebrafish were exposed to 60 mg/L IMI for 48 h and were evaluated using nLC-MS/MS for proteins, q-PCR analysis for expression of cat, gpx, pxr, ache, along with CAT and AChE enzyme activities and GSH and MDA assays. Based on proteomics, the regulation of antioxidant and immune responses, as well as gene transcription were significant processes affected. Apoptosis and ER stress pathways were upregulated and there was a down-regulation of cat and gpx genes. There was also elevated CAT activity and GSH and decreased MDA. Additionally, elevated AChE activity and up regulation of ache expression was observed. The multi-approach results included regulators of antioxidant, xenobiotic response and neuro-protective related proteins (genes and enzymes), which overall reflected harmful effects of IMI. Consequently, this study highlights the effects of IMI on zebrafish liver and reveals new potential biomarkers. In this respect, evaluated outcomes reveal the complementary features emphasizing the importance of studying chemicals using several methods. Our study provides deeper insights for future work in ecotoxicological studies regarding IMI and contribute to existing toxicity literature.

Thiosulfate-Cyanide Sulfurtransferase a Mitochondrial Essential Enzyme: From Cell Metabolism to the Biotechnological Applications

Thiosulfate: cyanide sulfurtransferase (TST), also named rhodanese, is an enzyme widely distributed in both prokaryotes and eukaryotes, where it plays a relevant role in mitochondrial function. TST enzyme is involved in several biochemical processes such as: cyanide detoxification, the transport of sulfur and selenium in biologically available forms, the restoration of iron–sulfur clusters, redox system maintenance and the mitochondrial import of 5S rRNA. Recently, the relevance of TST in metabolic diseases, such as diabetes, has been highlighted, opening the way for research on important aspects of sulfur metabolism in diabetes. This review underlines the structural and functional characteristics of TST, describing the physiological role and biomedical and biotechnological applications of this essential enzyme.