Differential role of MLKL in alcohol-associated and non-alcohol-associated fatty liver diseases in mice and humans

Metabolomics combined with network pharmacology reveals the protective effect of astragaloside IV on alcoholic liver disease

BACKGROUND

Alcoholic liver disease (ALD) is a significant contributor to liver damage. However, the clinical options for the treatment of ALD are limited. Astragaloside IV (AST-IV) is a saponin isolated from Astragalus membranaceus (AM). This study aimed to explore the underlying mechanisms of action of AST-IV in ALD by integrating metabolomics and network pharmacology.

METHODS

Sprague-Dawley (SD) rats were used to establish a rat model of ALD. AST-IV and polyene phosphatidyl choline (PPC; a positive control drug) were administered to rats with ALD for 4 weeks. We measured the body weight, liver index, ALT, AST, TC, TG, inflammatory markers (IL-1β, IL-6, and TNF-α), and oxidative stress markers (SOD, MDA) and used H&E and ORO staining to evaluate the hepatoprotective effect of both AST-IV and PPC on ALD. Subsequently, we performed untargeted metabolomics to predict the influence of AST-IV on lipid metabolism in rats with ALD. We then used a network pharmacology approach to identify the core targets through which AST-IV corrected lipid metabolism disorders and validated these targets through molecular docking, qRT-PCR and western blot analyses. Finally, we calculated the relationships between ALD-related biochemical markers, differential liver metabolites, and core targets using Spearman's correlation analysis.

RESULTS

AST-IV improved pathological damage and reduced lipid accumulation in the hepatocytes of rats with ALD. Furthermore, AST-IV inhibited oxidative stress and inflammatory responses in rats with ALD. The metabolomic results showed that AST-IV corrected hepatic lipid metabolism disorders by targeting linoleic acid, necrosis, sphingolipid, and glycerophospholipid metabolism. The Network pharmacology analysis revealed that the core targets of AST-IV exerting the above effects were p-RIPK3, p-MLKL, CYP1A2, CYP2C19, PPARα, PCSK9. Spearman's correlation analysis showed a strong correlation between ALD-related serum biochemical indices, core targets, and liver differential metabolites.

CONCLUSION

AST-IV corrects the metabolic disorders of linoleic acid, sphingolipid, and glycerophospholipid, and alleviates necrosis in rats with ALD through the core targets p-RIPK3, p-MLKL, CYP1A2, CYP2C19, PPARα, and PCSK9. This study is the first to reveal the mechanism of ALD protection through AST-IV from the perspective of metabolomics and network pharmacology. Therefore, a novel target has been identified to exert protection against ALD. This study provides a reference for ALD treatment.

Mediators of necroptosis: from cell death to metabolic regulation

Necroptosis, a programmed cell death mechanism distinct from apoptosis, has garnered attention for its role in various pathological conditions. While initially recognized for its involvement in cell death, recent research has revealed that key necroptotic mediators, including receptor-interacting protein kinases (RIPKs) and mixed lineage kinase domain-like protein (MLKL), possess additional functions that go beyond inducing cell demise. These functions encompass influencing critical aspects of metabolic regulation, such as energy metabolism, glucose homeostasis, and lipid metabolism. Dysregulated necroptosis has been implicated in metabolic diseases, including obesity, diabetes, metabolic dysfunction-associated steatotic liver disease (MASLD) and alcohol-associated liver disease (ALD), contributing to chronic inflammation and tissue damage. This review provides insight into the multifaceted role of necroptosis, encompassing both cell death and these extra-necroptotic functions, in the context of metabolic diseases. Understanding this intricate interplay is crucial for developing targeted therapeutic strategies in diseases that currently lack effective treatments.