Tanshinone IIA Sodium sulfonate regulates antioxidant system, inflammation, and endothelial dysfunction in atherosclerosis by downregulation of CLIC1

Abstract

Background: Tanshinone IIA Sodium sulfonate (STS) is clinically used for treating cardiovascular diseases in Traditional Chinese Medicine due to its antioxidation and anti-inflammation activities. Intracellular chloride channel 1 (CLIC1) participates in the regulation of oxidative stress and inflammation. This study investigates whether CLIC1 mediates the cardioprotective effects of STS.

Methods: STS were used to treat atherosclerosis (AS) induced by feeding Apolipoprotein E-deficient (ApoE^-/-) mice with a high-fat, cholesterol-rich diet. In addition, normal and CLIC1^-/- human umbilical vein endothelial cells were treated with STS after exposure to H₂O₂ for 12h. The oxidative status was determined by analyzing reactive oxygen species(ROS) and malondialdehyde (MDA) levels. ELISA, qRT-PCR and Western blot were used to determine the levels of TNF-α, IL-6, ICAM-1 and VCAM-1. CLIC1 cellular localization was examined by immunofluorescence. Chloride ion concentration was detected with chloride ion quenchers (MQAE).

Results: STS treatment decreased atherosclerotic lesion area by 3.5 times (P = 0.001) in vivo. Meanwhile, STS reduced MDA production (13.6%, P = 0.008), increased SOD activity (113.6%, P = 0.008), decreased TNF-α (38.6%, P = 0.008) and IL-6 (43.0%, P = 0.03) levels, and downregulated the expression of CLIC1, ICAM-1, and VCAM-1 in the atherosclerotic mice. The dose-dependent anti-oxidative and anti-inflammatory effects of STS were further confirmed in vitro. Furthermore, CLIC1 depletion abolished the STS-mediated decrease of ROS and MDA production in HUVEC cells. Additionally, STS inhibited both CLIC1 membrane translocation and chloride ion concentration.

Conclusion: The anti-oxidant, and anti-inflammation properties of STS in preventing AS is mediated by its inhibition of CLIC1 expression and membrane translocation.

Keywords: Atherosclerosis; Inflammation; Intracellular chloride channel 1; Oxidative stress; Tanshinone IIA Sodium sulfonate; Tanshinone IIA Sodium sulfonate (PubChem CID: 23669322).