Stevioside inhibits lipopolysaccharide-induced epithelial-to-mesenchymal transition of NRK-52E cells by PPARγ activation

Abstract

Background

Stevioside is a natural diterpenoid compound that possesses anti-inflammatory, immunomodulatory, anti-diabetic, anti-hypertensive, and renal protective effects, but its effect on lipopolysaccharide (LPS)-induced epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells, an important immune pathological mechanism of renal fibrosis, remains unknown. This study employed the renal proximal tubular cells NRK-52E to investigate the effect of stevioside.

Methods

The LPS-stimulated renal NRK-52E cells were treated with 50, 100, or 200 μM stevioside in the presence or absence of peroxisome proliferator-activated receptor γ (PPARγ) antagonist GW9662, the expression levels of intracellular E-cadherin, vimentin, α-smooth muscle actin (α-SMA), PPARγ, nuclear factor kappa B (NF-κB) p65, transforming growth factor-β1 (TGF-β1), signal transducer and activator of transcription 3 (STAT3), p-STAT3, Smad2/3, and p-Smad2/3 proteins were detected by Western blot analysis.

Results

In LPS-stimulated NRK-52E cells, stevioside treatment could reverse the expressions of EMT-related E-cadherin, vimentin, and α-SMA proteins, increase the expression of PPARγ protein, and decrease the expressions of NF-κB p65, TGF-β1, p-STAT3, Smad2/3, and p-Smad2/3 proteins, especially in the 200 μM stevioside-treated group. However, these beneficial effects of stevioside were attenuated or canceled by pretreatment with PPARγ antagonist GW9662.

Conclusions

Stevioside can inhibit the LPS-induced EMT via the reductions of NF-κB, TGF-β1, Smad2/3, p-Smad2/3, and p-STAT3 protein expressions by PPARγ activation in NRK-52E cells, which may provide a pharmacological basis for the potential application of stevioside in the prevention and treatment of renal fibrosis.

Keywords:

• Stevioside
• renal tubular epithelial cells
• epithelial-to-mesenchymal transition
• peroxisome proliferator-activated receptor γ
• nuclear factor kappa B

Author contributions

Wei Shen and Hui Huang performed the experimental research and drafted the manuscript. Jie Xue collected and analyzed the experimental data. Mei-Lin Xie designed the experimental study and reviewed the whole manuscript. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.