Autor: |
Konishi, Yuki, Okunishi, Atsuya, Sugihara, Fuminori, Nakamura, Tatsuya, Akazawa, Kazuki, Minoshima, Masafumi, Kikuchi, Kazuya |
Zdroj: |
Bulletin of the Chemical Society of Japan; June 2021, Vol. 94 Issue: 6 p1690-1694, 5p |
Abstrakt: |
Cathepsin K is a protease expressed in osteoclasts that degrades bone tissue, such as type I collagen fibers. Overexpression of cathepsin K is involved in osteoporosis, rheumatoid arthritis, and bone metastasis. Therefore, detecting cathepsin K activity is important for understanding the mechanism of these diseases and developing new drugs. However, current chemical probes cannot be employed for the detection of cathepsin K activity in animal deep-tissue. In this study, we developed novel 19F magnetic resonance imaging (MRI) probes (FLAME-(Gd-X), X = Acp, Deg, Deg2) to detect cathepsin K. In FLAME-(Gd-X), the Gd3+complex was modified on the surface of perfluorocarbon-encapsulated silica nanoparticles through cathepsin K substrate and three different hydrophobic/hydrophilic linkers. The 19F NMR signal intensities of these probes were suppressed by the paramagnetic relaxation enhancement (PRE) effect of the Gd3+complexes. The 19F MRI signal intensities of FLAME-Gd-Acp and FLAME-Gd-Deg specifically increased with the substrate cleavage by cathepsin K. The 19F MRI probes based on the PRE effect can be applied to the in vivo detection of cathepsin K activity.We developed 19F MRI probes to detect cathepsin K activity. These probes consist of perfluorocarbon-encapsulated silica nanoparticles, Gd3+complexes, cathepsin K substrates, and linkers. The 19F NMR signals of these probes were suppressed by the paramagnetic relaxation enhancement effect of the Gd3+complex. The 19F MRI signal intensities significantly increased after cleaving the substrates with Gd3+complexes by cathepsin K. |
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