Kinsenoside alleviates inflammation and fibrosis in experimental NASH mice by suppressing the NF-κB/NLRP3 signaling pathway

Abstract

Background: Non-alcoholic steatohepatitis (NASH) has replaced viral hepatitis as the main driver of the rising morbidity and mortality associated with cirrhosis and liver cancer worldwide, while no FDA-approved therapies are currently known. Kinsenoside (KD), naturally isolated from Anoectochilus roxburghii, possesses multiple biological activities, including lipolysis, anti-inflammation, and hepatoprotection. However, the effects of KD on NASH remain unclear.

Purpose: This study aimed to explore the roles of KD in NASH and its engaged mechanisms.

Methods: Two typical animal models of NASH, mice fed a methionine-choline-deficient (MCD) diet (representing non-obese NASH) and mice fed a high-fat and -fructose diet (HFFD) (representing obese NASH), were used to investigate the effect of KD on NASH in vivo. Transcriptome sequencing was performed to elucidate the underlying mechanisms of KD. Lipopolysaccharide (LPS)-stimulated THP-1 cells and transforming growth factor β1 (TGF-β1)-activated LX-2 cells were applied to further explore the effects and mechanisms of KD in vitro.

Results: The intragastric administration of KD remarkably alleviated MCD/HFFD-induced murine NASH almost in a dose-dependent manner. Specifically, KD reduced lipid accumulation, inflammation, and fibrosis in the liver of NASH mice. KD ameliorated alanine aminotransferase (ALT), aspartate aminotransferase (AST), superoxide dismutase (SOD), and malondialdehyde (MDA) abnormalities. In addition, it decreased the level of serum proinflammatory factors (IL-12p70, IL-6, TNF-α, MCP-1, IFN-γ) and the hepatic expression of typical fibrosis-related molecules (α-SMA, Col-I, TIMP-1). Mechanically, KD attenuated the MCD/HFFD-induced NASH through the inhibition of the NF-κB/NLRP3 signaling pathway. Consistently, KD reduced inflammation stimulated by LPS in THP-1 cells via suppressing the NF-κB/NLRP3 pathway. Furthermore, it prevented the activation of LX-2 cells directly, by inhibiting the proliferation stimulated by TGF-β1, and indirectly, by inactivating the NLRP3 inflammasome in macrophages.

Conclusion: For the first time, the practical improvement of NASH by KD was revealed. Our study found that KD exerted its alleviative effects on NASH through the inhibition of the NF-κB/NLRP3 signaling pathway. Given its hepatoprotective and nontoxic properties, KD has the potential to be a novel and effective drug to treat NASH.

Keywords: Fibrosis; Inflammation; Kinsenoside; NASH; NLRP3; Steatosis.