Physalin D attenuates hepatic stellate cell activation and liver fibrosis by blocking TGF-β/Smad and YAP signaling

Phytomedicine. 2020 Nov;78:153294. doi: 10.1016/j.phymed.2020.153294. Epub 2020 Jul 28.


Background: Hepatic fibrosis is considered integral to the progression of chronic liver diseases, as it leads to the development of cirrhosis and hepatocellular carcinoma. The activation of hepatic stellate cells (HSCs) is the dominant event in hepatic fibrogenesis. The transforming growth factor-β1 (TGF-β1) and Yes-associated protein (YAP) pathways play a pivotal role in HSC activation, hepatic fibrosis and cirrhosis progression. Therefore, targeting the TGF-β/Smad and YAP signaling pathways is a promising strategy for antifibrotic therapy.

Purpose: The present study investigated the protective effects of Physalin D (PD), a withanolide isolated from Physalis species (Solanaceae), against liver fibrosis and further elucidated the mechanisms involved in vitro and in vivo.

Study design/methods: We conducted a series of experiments using carbon tetrachloride (CCl4)- and bile duct ligation (BDL)-induced fibrotic mice and cultured LX-2 cells. Serum markers of liver injury, and the morphology, histology and fibrosis of liver tissue were investigated. Western blot assays and quantitative real-time PCR were used to investigate the mechanisms underlying the antifibrotic effects of PD.

Result: PD decreased TGF-β1-induced COL1A1 promoter activity. PD inhibited TGF-β1-induced expression of Collagen I and α-smooth muscle actin (α-SMA) in human hepatic stellate LX-2 cells. PD significantly ameliorated hepatic injury, including transaminase activities, histology, collagen deposition and α-SMA, in CCl4- or BDL-induced mice. Moreover, PD markedly decreased the expression of phosphorylated Smad2/3 in vitro and in vivo. Furthermore, PD significantly decreased YAP protein levels, and YAP knockdown did not further enhance the effects of PD, namely α-SMA inhibition, Collagen I expression and YAP target gene expression in LX-2 cells.

Conclusion: These results clearly show that PD ameliorated experimental liver fibrosis by inhibiting the TGF-β/Smad and YAP signaling pathways, indicating that PD has the potential to effectively treat liver fibrosis.

Keywords: HSC activation; Liver fibrosis; PD; TGF-β1/Smad; YAP.

MeSH terms

  • Actins / metabolism
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Carbon Tetrachloride / toxicity
  • Cells, Cultured
  • Collagen Type I / genetics
  • Collagen Type I, alpha 1 Chain
  • Hepatic Stellate Cells / drug effects*
  • Hepatic Stellate Cells / metabolism
  • Hepatic Stellate Cells / pathology
  • Humans
  • Liver Cirrhosis / drug therapy*
  • Liver Cirrhosis / metabolism
  • Liver Cirrhosis / pathology
  • Male
  • Mice, Inbred C57BL
  • Secosteroids / pharmacology*
  • Signal Transduction / drug effects
  • Smad Proteins / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transforming Growth Factor beta / metabolism*
  • Transforming Growth Factor beta / pharmacology
  • Transforming Growth Factor beta1
  • YAP-Signaling Proteins


  • ACTA2 protein, human
  • Actins
  • Adaptor Proteins, Signal Transducing
  • Collagen Type I
  • Collagen Type I, alpha 1 Chain
  • Secosteroids
  • Smad Proteins
  • TGFB1 protein, human
  • Transcription Factors
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • YAP-Signaling Proteins
  • YAP1 protein, human
  • physalin D
  • Carbon Tetrachloride