Certain carotenoids enhance the intracellular glutathione level in a murine cultured macrophage cell line by inducing glutamate-cysteine-ligase
Article first published online: 19 FEB 2014
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Molecular Nutrition & Food Research
Volume 58, Issue 6, pages 1291–1300, June 2014
How to Cite
Akaboshi, T. and Yamanishi, R. (2014), Certain carotenoids enhance the intracellular glutathione level in a murine cultured macrophage cell line by inducing glutamate-cysteine-ligase. Mol. Nutr. Food Res., 58: 1291–1300. doi: 10.1002/mnfr.201300753
- Issue published online: 5 JUN 2014
- Article first published online: 19 FEB 2014
- Manuscript Accepted: 20 DEC 2013
- Manuscript Revised: 12 DEC 2013
- Manuscript Received: 11 OCT 2013
- Grant-in-Aid for Scientific Research. Grant Number: 25504006
- Iijima Memorial Foundation
Glutathione (GSH) increases in RAW264 murine macrophage cells exposed to β-carotene or β-cryptoxanthin, however, the underlying mechanism has not been clarified. In the present study, we investigated the expression of glutamate-cysteine-ligase (GCL), the rate-limiting enzyme in GSH synthesis, in these cells.
Methods and results
Both the protein and mRNA expression of GCL increased in a β-carotene concentration-dependent manner. Buthionine sulfoximine, a GCL inhibitor, abolished the β-carotene-induced GSH increase without affecting the β-carotene-induced GCL protein expression. Both cycloheximide, a translation inhibitor, and actinomycin D, a transcription inhibitor, completely suppressed the β-carotene-induced GCL protein expression and the concomitant GSH increase. Actinomycin D inhibited the β-carotene-induced Gcl mRNA expression as well. Similarly to β-carotene, β-cryptoxanthin upregulated the GCL protein expression, but lutein did not. The c-Jun N-terminal kinase (JNK) inhibitor, SP600125, suppressed the β-carotene-induced GSH increase, whereas a p38 mitogen-activated protein kinase inhibitor or an extracellular signal-regulated kinase 1/2 inhibitor did not. The JNK inhibitor also suppressed the β-carotene-induced GCL protein expression, and consistently β-carotene induced JNK phosphorylation.
These findings revealed that certain carotenoids induce the Gcl mRNA expression in RAW264 cells and subsequently the GCL protein expression, which concomitantly enhances the intracellular GSH level, in a JNK pathway-related manner.