Chlorogenic Acid Inhibits Liver Fibrosis by Blocking the miR-21-Regulated TGF-β1/Smad7 Signaling Pathway in Vitro and in Vivo

Abstract

Aims: Chlorogenic acid (CGA) is a phenolic acid that has a wide range of pharmacological effects. However, the protective effects and mechanisms of CGA on liver fibrosis are not clear. This study explored the effects of CGA on miR-21-regulated TGF-β1/Smad7 liver fibrosis in the hepatic stellate LX2 cell line and in CCl4-induced liver fibrosis in Sprague-Dawley rats.Methods: The mRNA expression of miR-21, Smad7, connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), tissue inhibitor of metalloproteinase 1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), and transforming growth factor-β1 (TGF-β1) and the protein levels of Smad2, p-Smad2, Smad3, p-Smad3, Smad2/3, p-Smad2/3, Smad7, CTGF, α-SMA, TIMP-1, MMP-9 and TGF-β1 were assayed in LX2 cells and liver tissue. The effects of CGA after miR-21 knockdown or overexpression were analyzed in LX2 cells. The liver tissue and serum were collected for histopathological examination, immunohistochemistry (IHC) and ELISA.Results: The mRNA expression of miR-21, CTGF, α-SMA, TIMP-1, and TGF-β1 and the protein expression of p-Smad2, p-Smad3, p-Smad2/3, CTGF, α-SMA, TIMP-1, and TGF-β1 were inhibited by CGA both in vitro and in vivo. Meanwhile, CGA elevated the mRNA and protein expression of Smad7 and MMP-9. After miR-21 knockdown and overexpression, the downstream molecules also changed accordingly. CGA also lessened the degree of liver fibrosis in the pathological manifestation and reduced α-SMA and collagen I expression in liver tissue and TGF-β1 in serum. Conclusion: CGA might relieve liver fibrosis through the miR-21-regulated TGF-β1/Smad7 signaling pathway, which suggests that CGA might be a new anti-fibrosis agent that improves liver fibrosis.

Augmenter of liver regeneration protein deficiency promotes hepatic steatosis by inducing oxidative stress and microRNA‐540 expression

“…miR-199 is up-regulated in mice with methionine choline-deficient diet-induced NASH (43). Overexpression of miR-21 in liver fibrosis (44)(45)(46) and in patients with NASH but not bland steatosis (47,48) suggests its specific role in inflammation and fibrosis. miR-29 (and family members), another important miRNA implicated in fibrosis and whose targets include collagens, fibrillins, and elastin, showed delayed up-regulation in ALR-L-KO mice compared with the WT mice.…”

Molecular mechanism of myofibroblast formation and strategies for clinical drugs treatments in hypertrophic scars

“…Besides, miR-145 targeted Smad3, while miR-18 and miR-146a inhibited Smad4 expression (Knudsen et al, 2015). Smad7 played antagonistic roles in the fibrosis for TGF-β1 pathway and upregulation of miR-21 expression could reduce Smad7 expression (Ding et al, 2019;Wu et al, 2015;Yang et al, 2017).…”

Praziquantel ameliorates CCl4‐induced liver fibrosis in mice by inhibiting TGF‐β/Smad signalling via up‐regulating Smad7 in hepatic stellate cells

“…In contrast, Smad7 has a protective role as knockout of Smad7 promotes HSC activation and liver fibrosis in vivo and in vitro and Smad7 overexpression protects against liver fibrosis (Dooley et al, ; Dooley et al, ; Feng et al, ). In addition, Smad7 was identified as a target of microRNA‐21 (miR‐21) in a study (Yuan et al, ), which showed that up‐regulated miR‐21 promoted the activation of Smad proteins via inhibiting Smad7 in HSCs, thereby increasing the expression of collagens (He et al, ; Yang et al, ). A better understanding of the mechanisms underlying the activation of the TGF‐β/Smad signalling in diseases associated with fibrosis is a critical step towards the development of specific and novel antifibrosis drugs.…”