Abstract
Background and Purpose: Extracellular matrix (ECM) is mainly
derived from activated hepatic stellate cells (HSC), and its excessive
deposition is one of the characteristics of liver fibrosis. Accumulating
evidence indicated that the senescence of activated HSCs limits liver
fibrosis. Monomer derivative of paeoniflorin (MDP), a derivative of
paeoniflorin, inhibits inflammatory responses. However, the role and
fundamental mechanism of MDP in liver fibrosis was still unclear.
Experimental Approach: The effect of MDP was evaluated on
CCl4-induced C57BL/6J mice and TGF-β1-induced LX-2
cells. The level of SA-β-Gal was detected by SA-β-Gal kits. The cell
cycle was evaluated by flow cytometry. The expression of p16, p21, α-SMA
and Col. I proteins were analyzed by qRT-PCR, Western blots and
immunofluorescence staining and IHC staining. The pathological changes
of liver tissue were evaluated by histological analysis.
Key Results: We demonstrated that MDP inhibited the progression
of liver fibrosis in vivo and in vitro, concomitant with the elevated
expression of Ago2, miR-708 and p53 as well as the downregulated
expression of ZEB1. Mechanistic investigations revealed that MDP could
combined with Ago2, thus promoting the expression of miR-708.
Upregulation of miR-708 and p53 and downregulation of ZEB1 increased the
number of SA-β-Gal-positive HSCs and the expression levels of p16 and
p21 as well as decreased the expression of α-SMA and Col. I in activated
HSCs. Meanwhile, further studies revealed that miR-708 directly targeted
ZEB1, thus inhibiting the mRNA of ZEB1. More importantly, ZEB1 could
bind to the E‐box of p53 promoter and restrain its promoter activity as
well as thus block the expression of p53.
Conclusion and Implications: MDP could induce senescence of
activated HSCs via regulating Ago2/miR-708/ZEB1/p53 aixs and may be
applied to treat liver fibrosis.
Key Words: liver fibrosis; HSCs; MDP; miR-708; ZEB1