Topical Area: Carotenoids and Retinoids (CARIG)
Objectives : MicroRNAs (miRNAs) are known to be associated with human diseases, including liver fibrosis. We previously demonstrated that astaxanthin (ASTX), a xanthophyll carotenoid, has anti-fibrogenic effects in hepatic stellate cells (HSCs). HSCs are the major cell type responsible for the accumulation of extracellular matrix during the development of liver fibrosis once they are activated. The objective of this study was to compare miRNA expression profiles in activated HSCs (aHSCs) with those of quiescent HSCs (qHSCs) to identify miRNAs that may play crucial roles in the activation of HSCs. We also determined the effect of ASTX on the changes in miRNAs during HSC activation.
Methods : Primary mouse HSCs were cultured on uncoated plastic dishes for activation. The cells cultured for 1 day and 7 days after isolation served as qHSCs and aHSCs, respectively. qHSCs were treated with/without 25 µM ASTX during the activation for 7 days. miRNA expression profiles were determined using a miScript miRNA PCR array for mouse fibrosis. miRNAs whose expression were altered by more than 2-folds during HSC activation and by ASTX were selected. Their expression levels were further confirmed by quantitative real-time PCR in primary mouse and human HSCs and LX-2 cells, a human HSC cell line.
Results : Compared with qHSCs, the expression levels of 14 miRNAs and 23 miRNAs were increased and decreased by more than 2-folds, respectively, in aHSCs. Among 14 miRNAs increased in aHSCs, the expression of miR-192-5p, miR-382-5p, and miR-874-3p was reduced by ASTX. In addition, ASTX increased the expression of miR-19a-3p, miR-19b-3p, and miR-101a-3p which were among the 23 miRNAs that were decreased in aHSCs. Of the selected 6 miRNAs, miR-382-5p was chosen for further analysis based on its high expression in HSCs and the magnitude of differences between groups. Unlike in primary mouse HSCs, the expression of miR-382-5p was not altered by transforming growth factor β1, a fibrogenic cytokine, or by ASTX in primary human HSCs and LX-2 cells, which are cells somewhat activated.
Conclusions : We identified candidate miRNAs that may be important for the activation of HSCs from qHSCs, which were also sensitive to ASTX. Of the candidate miRNAs, miR-382-5p is likely involved in the early stage of HSC activation, i.e., transdifferentiation of qHSCs to aHSCs.
Funding Sources : NIH