The natural product-derived JM-9 alleviates high-fat diet-induced fatty liver in mice by targeting MD2.

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD), is gradually emerging as one of the most prevalent liver diseases worldwide. Previous research demonstrated the involvement of myeloid differentiation factor 2 (MD2), a co-receptor of TLR4, as a key mediator in MASLD pathogenesis. The current study identifies JM-9 as a novel MD2 inhibitor, and focuses on evaluating its potential therapeutic effects in mitigating MASLD progression.

Methods: Drug affinity responsive target stability (DARTS) assay and surface plasmon resonance assay were utilized to evaluate the MD2-targeting specificity of JM-9. In vitro, hepatocytes and macrophages were stimulated with palmitic acid (PA) followed by JM-9 treatment. In vivo, a high-fat diet (HFD)-induced MASLD model was established and subjected to JM-9 administration during the last 2 months.

Results: JM-9 directly bound the Phe76 residue of MD2 to disrupt the PA-induced MD2/TLR4 complex formation, thus further restoring AMPK phosphorylation and inhibiting NF-κB activation to reducing lipid accumulation and inflammation, respectively. In the HFD-mediated MASLD mouse model, JM-9 alleviated the binding between MD2 and TLR4 in the liver and counteracted hepatic TBK1 and p65 activation and AMPK suppression, thereby mitigating liver inflammation, steatosis, and fibrosis.

Conclusion: JM-9, as a novel MD2 inhibitor, holds potential as a viable treatment option for MASLD by playing a dual role in regulating both lipid metabolism and inflammation response.