Linderae Radix Attenuates Hyperlipidemia by Regulating Reverse Cholesterol Transport through the miR-33-PPARα/LXRα...

It has been reported that miR-33 could down-regulate the key protein expression of reverse cholesterol transport (RCT) to clear excess cholesterol. Our previous studies reported that Linderae Radix (Wuyao in Chinese, WY) has a strong anti-hyperlipidemia effect by regulating RCT, but whether the regulation of WY on RCT is related to miR-33 remains unclear.

In in vivo research, mice were randomly divided into five groups. miR-33 agomir was administered to hyperlipidemic (HLP) mice to establish a miR-33 over-expression model. The anti- hyperlipidemic effect of WY in mice was evaluated by serum lipid profile, hematoxylin and eosin (H&E) staining, and Oil Red O staining. In vitro, the effect of WY on cholesteryl ester and uptake was measured in ox-LDL-induced RAW 264.7 cells. We established cell models with either overexpression or low expression of miR-33. The effect of WY on the expression of proteins related to reverse cholesterol transport (RCT) was evaluated using RT-qPCR, Western blotting, Wes automated protein expression analysis, and multiplex immunofluorescence assays.

WY could significantly reduce TC, TG, and LDL-C levels and improve lipid accumulation in the liver of both HLP mice and miR-33 over-expression HLP mice. Moreover, RCT-related proteins, such as ABCA1, ABCG1, PPARα, LXRα, and farnesoid X receptor (FXR), were also increased after WY treatment. The same trend was observed in vitro, that WY could alleviate lipid deposition in macrophages. Compared with the miR-33 mimic group, the expression of ABCA1, ABCG1, SR-BI, and LXRα was significantly increased in RAW264.7 cells incubated with WY. Compared with the miR-33 inhibitor group, WY markedly enhanced the expression levels of ABCA1, ABCG1, LXRα, and SR-BI in cells with low miR-33 expression.

Activation of PPARα/LXRα by Linderae Radix through miR-33 inhibition represents a mechanistically distinct approach from statins or fibrates, potentially benefiting statin-intolerant patients or serving as an adjunct therapy.

These findings suggest that WY could attenuate hyperlipidemia by regulating RCT through the miR-33-PPARα/LXRα axis.