Photocontrollable peroxynitrite generator based on N-methyl-N-nitrosoaminophenol for cellular application

Area of Science:

• Photochemistry
• Chemical Biology
• Biomedical Engineering

Background:

• Peroxynitrite (ONOO(-)) is a reactive nitrogen species implicated in various biological processes.
• Existing ONOO(-) generators lack precise spatiotemporal control, limiting their use in complex biological systems.
• Development of photocontrollable ONOO(-) donors is crucial for studying its biological roles with high fidelity.

Purpose of the Study:

• To design and synthesize a novel photocontrollable peroxynitrite (ONOO(-)) generator, termed P-NAP.
• To characterize the mechanism of P-NAP-mediated ONOO(-) generation upon photoirradiation.
• To demonstrate the utility of P-NAP for biological imaging in cultured cells.

Main Methods:

• Synthesis and structural characterization of the P-NAP compound.
• Photochemical studies involving UV-A irradiation and analysis of reaction intermediates and products (ESR, HPLC).
• Quantification of ONOO(-) generation using a specific fluorogenic probe (HKGreen-3) and actinometry.
• Cell-based imaging experiments using HCT-116 cells and a fluorescent probe (HKGreen-3A).

Main Results:

• P-NAP successfully generated nitric oxide (NO) and superoxide radical anion (O(2)(•-)) upon UV-A irradiation, leading to ONOO(-) formation.
• The reaction mechanism involves photoinduced NO release, O(2)(•-) generation, and subsequent ONOO(-) synthesis.
• P-NAP demonstrated efficient ONOO(-) generation in cultured HCT-116 cells, visualized via fluorescence imaging.
• The quantum yield for duroquinone formation was determined to be 0.86 ± 0.07.

Conclusions:

• P-NAP represents the first photocontrollable peroxynitrite (ONOO(-)) donor applicable to live cultured cells.
• This novel generator offers precise spatiotemporal control over ONOO(-) generation for biological studies.
• P-NAP holds significant potential for investigating the roles of ONOO(-) in cellular processes and disease models.