Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, China.
Immunopharmacol Immunotoxicol. 2022 Apr;44(2):287-294. doi: 10.1080/08923973.2022.2039935. Epub 2022 Feb 10.
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.
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.
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.
Stevioside can inhibit the LPS-induced EMT 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.
甜菊糖苷是一种天然二萜类化合物，具有抗炎、免疫调节、抗糖尿病、抗高血压和肾保护作用，但它对脂多糖 (LPS) 诱导的肾小管上皮细胞上皮-间充质转化 (EMT) 的影响，即肾纤维化的一个重要免疫病理机制，尚不清楚。本研究采用肾近端小管细胞 NRK-52E 来探讨甜菊糖苷的作用。
用 LPS 刺激 NRK-52E 细胞，然后用 50、100 或 200 μM 的甜菊糖苷处理，同时用过氧化物酶体增殖物激活受体 γ (PPARγ) 拮抗剂 GW9662 处理，用 Western blot 分析检测细胞内 E-钙黏蛋白、波形蛋白、α-平滑肌肌动蛋白 (α-SMA)、PPARγ、核因子 kappa B (NF-κB) p65、转化生长因子-β1 (TGF-β1)、信号转导和转录激活因子 3 (STAT3)、p-STAT3、Smad2/3 和 p-Smad2/3 蛋白的表达水平。
在 LPS 刺激的 NRK-52E 细胞中，甜菊糖苷处理可逆转 EMT 相关的 E-钙黏蛋白、波形蛋白和 α-SMA 蛋白的表达，增加 PPARγ 蛋白的表达，并降低 NF-κB p65、TGF-β1、p-STAT3、Smad2/3 和 p-Smad2/3 蛋白的表达，特别是在 200 μM 甜菊糖苷处理组。然而，用 PPARγ 拮抗剂 GW9662 预处理可减弱或消除甜菊糖苷的这些有益作用。
甜菊糖苷可抑制 LPS 诱导的 EMT，通过激活 PPARγ，降低 NRK-52E 细胞中 NF-κB、TGF-β1、Smad2/3、p-Smad2/3 和 p-STAT3 蛋白的表达，这可能为甜菊糖苷在预防和治疗肾纤维化中的潜在应用提供药理学基础。
