MiR-125b-5p is targeted by curcumin to regulate the cellular antioxidant capacity

Abstract

As a natural polyphenolic food supplement and the principal curcuminoid in turmeric, curcumin shows antioxidant, anti-inflammatory, and antitumor activities. However, its specific functional mechanism remains unclear. Our preliminary study indicated that miR-125b-5p was downregulated by a curcumin extract. This study aimed to determine whether miR-125b-5p is involved in the antioxidant regulation of curcumin. The results showed that miR-125b-5p overexpression had a pro-oxidant effect by reducing the cellular antioxidant capacity, as well as decreasing the activities of catalase (CAT) and superoxide dismutase (SOD) in the normal liver cell line LO2. However, miR-125b-5p repression significantly increased the cellular antioxidant capacity and enhanced the activities of CAT and SOD. Further investigation demonstrated that the cellular antioxidant capacity induced by curcumin extract was inhibited by miR-125b-5p overexpression. Thus, curcumin may exhibit antioxidant effects by repressing miR-125b-5p expression, which provides new insights into the molecular antioxidant mechanism of curcumin and other functional food components.

Keywords:

• microRNA
• reactive oxygen species
• mitochondria
• oxidative stress
• polyphenol

Author contributions

Lingli Lin: methodology, investigation, data curation, writing—original draft preparation, writing—reviewing and editing. Xi Chen: investigation, data curation. Xiaoting Sun and Baoping Xiao: writing—original draft preparation, writing reviewing and editing. Jian Li: resources, data curation. Jingwen Liu: resources, data curation, funding acquisition. Guiling Li: conceptualization, supervision, writing—original draft preparation, writing—reviewing and editing, projection administration, funding acquisition.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant nos. 31771972 and 42076086) and the Natural Science Foundation of Fujian Province (grant nos. 2020J01676 and 2019J05096).