Elucidating the Relationship between ROS and Protein Phosphorylation through In Situ Fluorescence Imaging in the Pneumonia Mice

Revealing the relationship between reactive oxygen species (ROS) and levels of protein phosphorylation is of great significance for understanding the pathogenesis of diseases. Although mass spectrometry is used as a classical method for protein phosphorylation analysis, there are still some challenges to realize in vivo protein phosphorylation recognition. Herein, we designed and prepared an metal–organic framework (MOF)-based fluorescent nanoprobe with Zr(IV) and boronate ester as an active center, which achieved simultaneous recognition of ROS and phosphorylation sites. The ROS unit was constructed by 1,8-naphthalimide and boronate ester as a fluorophore and a recognition group, respectively. The specific interaction between Zr(IV) and a phosphate group was used to realize fluorescence imaging of phosphorylation sites. Using the advantages of two-photon property of the ROS recognition unit, the nanoprobe can effectively reduce the background fluorescence and thus improve the imaging sensitivity. Finally, the MOF-based nanoprobe was successfully applied to reveal the relationship between ROS and levels of phosphorylation in pneumonia mice, which illustrated that the ROS and phosphorylation levels in the process of pulmonary inflammation were obviously higher than those of the normal mice. This work provides feasible fluorescence tools that have important significance for revealing pathogenesis of diseases.