title: Specific detection and imaging of enzyme activity by signal-amplifiable self-assembling (19)F MRI probes.
abstract: Specific turn-on detection of enzyme activities is of fundamental importance in drug discovery research, as well as medical diagnostics. Although magnetic resonance imaging (MRI) is one of the most powerful techniques for noninvasive visualization of enzyme activity, both in vivo and ex vivo, promising strategies for imaging specific enzymes with high contrast have been very limited to date. We report herein a novel signal-amplifiable self-assembling (19) F NMR/MRI probe for turn-on detection and imaging of specific enzymatic activity. In NMR spectroscopy, these designed probes are "silent" when aggregated, but exhibit a disassembly driven turn-on signal change upon cleavage of the substrate part by the catalytic enzyme. Using these (19) F probes, nanomolar levels of two different target enzymes, nitroreductase (NTR) and matrix metalloproteinase (MMP), could be detected and visualized by (19) F NMR spectroscopy and MRI. Furthermore, we have succeeded in imaging the activity of endogenously secreted MMP in cultured media of tumor cells by (19) F MRI, depending on the cell lines and the cellular conditions. These results clearly demonstrate that our turn-on (19) F probes may serve as a screening platform for the activity of MMPs.
authors: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-Ku, Kyoto 615-8510 (Japan), Fax: (+81) 75-383-2759.
authors: Kazuya
authors: K
authors: Matsuo
authors: Rui
authors: R
authors: Kamada
authors: Keigo
authors: K
authors: Mizusawa
authors: Hirohiko
authors: H
authors: Imai
authors: Yuki
authors: Y
authors: Takayama
authors: Michiko
authors: M
authors: Narazaki
authors: Tetsuya
authors: T
authors: Matsuda
authors: Yousuke
authors: Y
authors: Takaoka
authors: Itaru
authors: I
authors: Hamachi
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry; D005462:Fluorine Radioisotopes / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008279:Magnetic Resonance Imaging; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D018613:Microscopy, Confocal; D015335:Molecular Probes / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry; D013379:Substrate Specificity
chemical_list: D005456:Fluorescent Dyes; D005462:Fluorine Radioisotopes; D015335:Molecular Probes; D010455:Peptides; D020782:Matrix Metalloproteinases
keywords: NMR spectroscopy; enzyme activity; imaging agents; magnetic resonance imaging; self-assembly; signal amplification