Ginsenoside Rh4 Improves Hepatic Lipid Metabolism and Inflammation in a Model of NAFLD by Targeting the Gut Liver Axis and Modulating the FXR Signaling Pathway

Bruceine A alleviates alcoholic liver disease by inhibiting AIM2 inflammasome activation via activating FXR

BACKGROUND

Alcoholic liver disease (ALD), a public health challenge worldwide caused by long-term persistent drinking, is life-threatening with minimal approved therapies. Hepatic steatosis accompanied by inflammation is an initial and inevitable stage in the complex progression of simple alcoholic liver injury to more severe liver diseases such as hepatitis, liver fibrosis, cirrhosis and liver cancer.

PURPOSE

We aimed to identify the therapeutic role of Bruceine A (BA) in ALD whilst attempting to explore whether its protective effects depend specifically on the farnesoid X receptor (FXR).

METHODS

Autodock was applied to detect the affinity between BA and FXR. Lieber-DeCarli liquid diet with 5 % ethanol (v/v) was adopted to establish the mouse ALD model. The lentivirus mediating FXR (LV-FXR) was injected into mice via the tail vein to establish FXR-overexpressed mice. FXR silencing or overexpression plasmids were transfected into AML-12 cells prior to ethanol stimulation. Quantitative real-time PCR, Western blotting and immunofluorescence assays were employed to determine the expression of related genes. We subjected liver sections to H&E and Oil Red O staining to evaluate the liver histological injury and the deposition of lipid droplets.

RESULTS

BA significantly reduced body weight and liver-to-body weight ratios as well as biochemical indexes in mice. Ethanol-induced liver damage and lipid accumulation could be alleviated by BA treatment. BA bound to FXR by two hydrogen bonds. There was a positive correlation between BA administration and FXR expression. BA inhibited the expression of lipid synthesis genes and enhanced the expression of lipid metabolism genes by activating FXR, thus alleviating steatosis in ALD. Moreover, BA exerted an ameliorative effect against inflammation by inhibiting the activation of absent in melanoma 2 (AIM2) inflammasome by activating FXR. FXR overexpression possessed the ability to counter the accumulation of lipid and the activation of AIM2 inflammasome caused by ethanol. FXR deficiency exacerbated ethanol-induced liver steatosis and inflammation. The hepatoprotective effect of BA could be disrupted by FXR antagonist guggulsterone (GS) in vivo and FXR siRNA in vitro.

CONCLUSION

BA alleviated alcoholic liver disease by inhibiting AIM2 inflammasome activation through an FXR-dependent mechanism. This study may potentially represent a new therapeutic approach for ALD.

The gut-liver axis in fatty liver disease: role played by natural products

Fatty liver disease, a condition characterized by fatty degeneration of the liver, mainly classified as non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD), has become a leading cause of cirrhosis, liver cancer and death. The gut-liver axis is the bidirectional relationship between the gut and its microbiota and its liver. The liver can communicate with the gut through the bile ducts, while the portal vein transports the products of the gut flora to the liver. The intestinal flora and its metabolites directly and indirectly regulate hepatic gene expression, leading to an imbalance in the gut-liver axis and thus contributing to the development of liver disease. Utilizing natural products for the prevention and treatment of various metabolic diseases is a prevalent practice, and it is anticipated to represent the forthcoming trend in the development of drugs for combating NAFLD/ALD. This paper discusses the mechanism of the enterohepatic axis in fatty liver, summarizes the important role of plant metabolites in natural products in fatty liver treatment by regulating the enterohepatic axis, and provides a theoretical basis for the subsequent development of new drugs and clinical research.

Ginsenoside RH4 inhibits Ang II-induced myocardial remodeling by interfering with NFIL3

Ventricular remodeling refers to the structural and functional changes of the heart under various stimuli or disease influences and may also be accompanied by myocardial fibrosis, where an excessive amount of fibrous tissue appears in the myocardial tissue, affecting the heart's normal contraction and relaxation. Hypertension is posing the potential risk of causing myocardial injury and remodeling. The significance of the renin-angiotensin-aldosterone system (RAAS) in myocardial remodeling cannot be overlooked. Drug targeting of RAAS can effectively lower blood pressure and reduce left ventricular mass. Studies have shown that ginsenoside Rh4 can inhibit oxidative stress and inflammatory responses. In this study, a myocardial remodeling model was established using angiotensin (Ang) II, and the inhibitory effect of RH4 on myocardial hypertrophy and remodeling induced by Ang II was investigated using pathological staining and quantitative polymerase chain reaction (qPCR). Immunofluorescence and qPCR demonstrated that Rh4 causes myocardial hypertrophy and the generation of reactive oxygen species (ROS) in vitro. The Rh4 target was identified using transcriptomics. The findings indicated that RH4 could inhibit myocardial hypertrophy, inflammatory fibrosis, and oxidative stress induced by Ang II, suggesting potential cardiovascular protection effects. In vitro experiments have shown that Rh4 inhibits myocardial hypertrophy. Transcriptomics revealed that nuclear factor interleukin-3 (NFIL3) is a downstream regulator of Rh4. By constructing AAV9-NFIL3 and injecting it into mice, it was found that NFIL3 overexpression interfered with anti-Ang II-induced myocardial remodeling of Rh4. These results indicate that Rh4 demonstrates potential therapeutic effects on myocardial hypertrophy and fibrosis.

Disrupting the gut microbiota/metabolites axis by Di-(2-ethylhexyl) phthalate drives intestinal inflammation via AhR/NF-κB pathway in mice

Di-(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer known for its environmental endocrine-disrupting properties, posing potential risks to various organs. However, the precise impact of DEHP on intestinal health and its contribution to the initiation of intestinal inflammation remains elucidated. This study aims to investigate the underlying mechanisms of DEHP-induced intestinal inflammation in mice, specifically focusing on the complex interplay between the gut microbiota-metabolite axis and associated pathophysiological alterations. Our findings showed that DEHP-induced damage of multiple organs systemically, as indicated by abnormal liver and kidney biochemical markers, along with a disrupted ileum morphology. Additionally, DEHP exposure disrupted gut barrier function, causing intestinal inflammation characterized by bacterial translocation and alterations in defense and inflammation-related gene expressions. Moreover, 16S rRNA analysis suggested that DEHP-induced gut microbial remodeling is characterized by an upregulation of detrimental bacteria (Erysipelotrichaceae) and a downregulation of beneficial bacteria (Muribaculaceae, Ruminococcaceae, and Lachnospiraceae). Metabolomics analysis revealed DEHP perturbed gut metabolic homeostasis, particularly affecting the degradation of aromatic compounds, which generated an aberrant activation of the AhR and NF-κB, subsequently causing intestinal inflammation. Consequently, our results elucidate the mechanistic link between disrupted gut microbiota and metabolome and the initiation of DEHP-induced intestinal inflammation, mediated through the AhR/NF-κB signaling pathway.

Thyme (Thymus quinquecostatus Celak) Polyphenol-Rich Extract (TPE) Alleviates HFD-Induced Liver Injury in Mice by Inactivating the TLR4/NF-κB Signaling Pathway through the Gut-Liver Axis

Non-alcoholic fatty liver disease (NAFLD) represents a significant and urgent global health concern. Thyme (Thymus quinquecostatus Celak) is a plant commonly used in cuisine and traditional medicine in Asian countries and possesses potential liver-protective properties. This study aimed to assess the hepatoprotective effects of thyme polyphenol-rich extract (TPE) on high-fat diet (HFD)-induced NAFLD and further explore possible mechanisms based on the gut-liver axis. HFD-induced liver injury in C57 mice is markedly ameliorated by TPE supplementation in a dose-dependent manner. TPE also regulates the expression of liver lipid metabolic genes (i.e., Hmgcr, Srebp-1, Fasn, and Cyp7a1), enhancing the production of SCFAs and regulating serum metabolites by modulating gut microbial dysbiosis. Furthermore, TPE enhances the intestinal barrier function and alleviates intestinal inflammation by upregulating tight junction protein expression (i.e., ZO-1 and occluding) and inactivating the intestinal TLR4/NF-κB pathway in HFD-fed mice. Consequently, gut-derived LPS translocation to the circulation was blocked, the liver TLR4/NF-κB signaling pathway was repressed, and subsequent pro-inflammatory cytokine production was restrained. Conclusively, TPE might exert anti-NAFLD effects through the gut-liver axis and has the potential to be used as a dietary supplement for the management of NAFLD.