Inhibition of neutrophil superoxide generation by shikonin is associated with suppression of cellular Ca2+ fluxes
| Autor: | Hirokazu Kawagishi, Hiromi Takano-Ohmuro, Lucia Satiko Yoshida, Yasukatsu Yuda, Naokazu Morishita, Kimiko Kazumura, Tomohito Kakegawa, Hiroshi Tsuchiya, Akiko Hara |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Nutrition and Dietetics NADPH oxidase biology Chemistry Superoxide Clinical Biochemistry Medicine (miscellaneous) Nanotechnology Monitoring system Fluorescence law.invention Intracellular ca 03 medical and health sciences chemistry.chemical_compound 030104 developmental biology law biology.protein Ic50 values Biophysics Inositol Chemiluminescence |
| Zdroj: | Journal of Clinical Biochemistry and Nutrition. 59:1-9 |
| ISSN: | 1880-5086 0912-0009 |
| DOI: | 10.3164/jcbn.16-4 |
| Popis: | Shikonin, an anti-inflammatory compound of "Shikon", inhibits the neutrophil superoxide (O2 (•-)) generation by NADPH oxidase 2 (Nox2); however, the mechanisms of how shikonin affects Nox2 activity remained unclear. We aimed to elucidate the relationship between the inhibition of Nox2 activity and influences on intracellular Ca(2+) concentration ([Ca(2+)]i) by shikonin. For this purpose, we used a simultaneous monitoring system for detecting changes in [Ca(2+)]i (by fluorescence) and O2 (•-) generation (by chemiluminescence) and evaluated the effects of shikonin on neutrophil-like HL-60 cells stimulated with N-formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLP). Since fMLP activates Nox2 by elevation in [Ca(2+)]i via fluxes such as inositol 1,4,5-trisphosphate-induced Ca(2+) release (IICR) and store-operated Ca(2+) entry (SOCE), we also evaluated the effects of shikonin on IICR and SOCE. Shikonin dose-dependently inhibited the fMLP-induced elevation in [Ca(2+)]i and O2 (•-) generation (IC50 values of 1.45 and 1.12 µM, respectively) in a synchronized manner. Analyses of specific Ca(2+) fluxes showed that shikonin inhibits IICR and IICR-linked O2 (•-) generation (IC50 values: 0.28 and 0.31 µM for [Ca(2+)]i and O2 (•-), respectively), as well as SOCE and SOCE-linked O2 (•-) generation (IC50 values: 0.39 and 0.25 µM for [Ca(2+)]i and O2 (•-), respectively). These results suggested that shikonin inhibits the O2 (•-) generation by Nox2 in fMLP-stimulated neutrophils by targeting Ca(2+) fluxes such as IICR and SOCE. |
| Databáze: | OpenAIRE |
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