Monitoring of hydrogen peroxide production under photodynamic treatment using protein sensor HyPer.

An interest to H2O2 accumulation under photodynamic treatment can be explained by its participation in intracellular signal cascades. It is important not only to detect H2O2 generation, but also to trace the dynamics of its intracellular content. In the present study the dynamics of cellular H2O2 content under photodynamic treatment was analyzed using genetically encoded reversible H2O2-sensitive sensor HyPer. Real-time detecting of H2O2 production after photodynamic treatment was performed using the protein sensor and individual features of action of different photosensitizers were revealed. Photodynamic treatment with a number of chlorin and phthalocyanine photosensitizers was found to induce secondary production of H2O2 in the cells. Three types of dynamic responses were registered: monotonous increase of H2O2 level during the entire observation time in the presence of Fotoditazin and Holosens; transient short-term accumulation in the presence of Radachlorin and Phthalosens; and relatively low-level stable increase in the presence of Photosens. The listed photosensitizers differ significantly in intracellular localization and physicochemical properties, which can determine the differences in the response of H2O2 after the photodynamic treatment. In general, it has been shown that the rapid transient H2O2 response is typical for hydrophobic compounds localized in membrane cell structures, whereas in the presence of more hydrophilic dyes a prolonged monotonous H2O2 accumulation occurs.