Molecular Imaging of Peroxynitrite with HKGreen-4 in Live Cells and Tissues

Abstract

Peroxynitrite (ONOO(-)), the product of a radical combination reaction of nitric oxide and superoxide, is a potent biological oxidant involved in a broad spectrum of physiological and pathological processes. Herein we report the development, characterization, and biological applications of a new fluorescent probe, HKGreen-4, for peroxynitrite detection and imaging. HKGreen-4 utilizes a peroxynitrite-triggered oxidative N-dearylation reaction to achieve an exceptionally sensitive and selective fluorescence turn-on response toward peroxynitrite in chemical systems and biological samples. We have thoroughly evaluated the utility of HKGreen-4 for intracellular peroxynitrite imaging and, more importantly, demonstrated that HKGreen-4 can be efficiently employed to visualize endogenous peroxynitrite generated in Escherichia coli-challenged macrophages and in live tissues from a mouse model of atherosclerosis. This probe should serve as a powerful molecular imaging tool to explore peroxynitrite biology under a variety of physiological and pathological contexts.

Phenylboronic Acid-based 19F MRI Probe for the Detection and Imaging of Hydrogen Peroxide Utilizing Its Large Chemical-Shift Change

“…19 F NMR spectra were acquired using a Bruker Avance III spectrometer (376 MHz for 19 F NMR) and a JEOL ECS400 spectrometer (376 MHz for 19 F NMR). Chemical shifts are reported in ppm, relative to trifluoroacetic acid (TFA, δ = -76.5 ppm) as an internal standard.…”

“…9 Indeed, MR chemical probes and contrast agents have been designed for such a purpose. 10 The MR modality, however, has an intrinsic problem for the selective detection of chemical probes because of large background signals resulting from endogenous MRdetectable nuclei such as 1 H, 13 C, and 31 P. To overcome this limitation, 19 F MR has received attention in recent years. 11 19 F is an MR-detectable nucleus that has a relatively high sensitivity (83% of 1 H) in spite of the absence of background signals in biological samples.…”

“…11 19 F is an MR-detectable nucleus that has a relatively high sensitivity (83% of 1 H) in spite of the absence of background signals in biological samples. By utilizing these advantages, many 19 F MR probes have been developed and some probes have been applied to in vivo MRI experiments. 12 With respect to 19 F ROS probes, nitric oxide (NO), 13 hypochlorous acid (HOCl), 14 and peroxynitrite ion (ONOO -) 15 probes have been used for the in vitro detection of each target.…”

“…12 With respect to 19 F ROS probes, nitric oxide (NO), 13 hypochlorous acid (HOCl), 14 and peroxynitrite ion (ONOO -) 15 probes have been used for the in vitro detection of each target. However, to our knowledge, no 19 F MRI prove for H2O2 imaging has yet been produced.…”

“…Here, we report on a new 19 F MRI probe for the detection of H2O2. The probe reacted promptly with H2O2 with a large 19 …”