Turnera diffusa extract attenuates profibrotic, extracellular matrix and mitochondrial markers in activated human hepatic stellate cells (HSC)

Abstract

Introduction and objectives: Hepatic fibrosis is characterized by the accumulation of extracellular matrix which includes the accumulation of α-smooth muscle actin (α-SMA), collagen type I (COL1α1), as well as remodeling induced by metalloproteinases and tissue inhibitor of metalloproteinase (TIMPs), where hepatic stellate cells (HSCs) play a central role. In addition, the transcription factor SNAI1 (which participates in epithelial-mesenchymal transition, EMT) and mitofusin 2 (MFN2, a mitochondrial marker) plays an important role in chronic liver disease. Turnera diffusa (TD), a Mexican endemic plant, has been shown to possess antioxidant and hepatoprotective activity in vitro. We treated human HSC (LX2 cells) with a methanolic extract of Turnera diffusa (METD) to evaluate the mechanism involved in its hepatoprotective effect measured as fibrosis modulation, EMT, and mitochondrial markers.

Materials and methods: HSC LX-2 cells were treated with METD (100 and 200ng/mL) alone or combined with TGF-β (10ng/mL) at different time points (24, 48, and 72h). α-SMA, COL1α1, MMP2, TIMP1, SNAI1, and MFN2 mRNAs and protein levels were determined by real-time quantitative PCR and Western Blot analysis.

Results: We found that METD decreases COL1α1-mRNA, α-SMA, and TIMP1 protein expression in LX2 cells treated with and TGF-β. This treatment also decreases MFN2 and TIMP1 protein expression and induces overexpression of MMP2-mRNA.

Conclusions: Our results suggest that a methanolic extract of Turnera diffusa is associated with an antifibrotic effect by decreasing profibrotic and mitochondrial markers together with the possible induction of apoptosis through SNAI1 expression in activated HSC cells.

Keywords: Fibrosis; Hepatic stellate cells (HSC); Liver; Natural products; Turnera diffusa.