Research on mitochondrial oxidative stress accompanying the diabetic process under airborne particulate matter pollution by NIR fluorescence imaging of cysteine

Complex airborne particulate matter (APM) pollution seriously destroys the redox balance of organisms. Diabetes is a chronic disorder of the redox system, and its progression is usually accompanied by mitochondrial oxidative stress. The role of cysteine (Cys) in the process of mitochondrial oxidative stress is crucial as an essential scavenger of reactive oxygen species. Consequently, it is of great value to investigate the link between mitochondrial oxidative stress and diabetes by measuring changes in mitochondrial cysteine levels. However, it has not been revealed how the levels of Cys change in the mitochondria during diabetes. Therefore, we designed a novel mitochondria-targeted near-infrared fluorescent probe to assay cysteine. Importantly, by using the new probe, we discovered that mitochondrial Cys levels were significantly decreased in the diabetic cells and mice. We also uncovered that a dramatic reduction of Cys levels in the mice exposed to the presence of excess particulate matter from environmental pollution, for the first time. These findings will provide valuable insights into new treatments for diabetes and offer a practical tool to unravel the connection between mitochondrial oxidative stress and associated diseases. We believe this research will help experts to better understand the role of Cys under the APM threat.