Metabolic dysfunction-associated fatty liver disease (MASLD) is a major global health challenge characterized by metabolic imbalance, inflammation, and oxidative stress, yet effective targeted therapies remain limited. Lipoprotein-associated phospholipase A2 (Lp-PLA2) has emerged as a potential regulator of metabolic disorders, but its role and therapeutic relevance in MASLD remain unclear. Integrative bioinformatics analysis of human liver transcriptomic datasets combined with virtual screening, network pharmacology, and molecular docking identified chebulinic acid (CA) as a potential Lp-PLA2-targeting compound. The therapeutic effects and underlying mechanisms of CA were investigated using high-fat diet (HFD)-induced MASLD mouse models and free fatty acid (FFA)-treated Huh7 hepatocytes using metabolic profiling, histological analysis, Seahorse bioenergetic assessment, adeno-associated virus (AAV)-mediated gene overexpression, and cellular thermal shift assay. Lp-PLA2 was identified as a key regulator associated with MASLD progression and metabolic pathway dysregulation. CA exhibited strong binding affinity to Lp-PLA2 and significantly ameliorated metabolic dysfunction, hepatic steatosis, inflammation, and oxidative stress in both in vivo and in vitro models. Mechanistically, CA restored mitochondrial respiration and glycolytic capacity while reducing abnormal HK2 expression. HK2 overexpression abolished the protective effects of CA, indicating that excessive HK2 expression contributes to metabolic imbalance under metabolic stress conditions. Furthermore, CA CA binding to Lp-PLA2 through the Glu304 residue was required for its metabolic protective effects and was associated with regulation of the Lp-PLA2-HK2-associated pathway. This study identifies Lp-PLA2-associated HK2 dysregulation as a potential contributor to MASLD metabolic dysfunction and demonstrates that CA improves hepatic metabolic homeostasis through modulation of Lp-PLA2 signaling.
Yinghui Wang, Guo-Chun Zhang, Xicheng Jiang et al.· Journal of Nutritional Bioch...· 0 citations
ABSTRACT Tumor metabolic dysregulation is a critical determinant of tumor progression and response to immunotherapy. Aberrant glutamine metabolism is a hallmark of gastric cancer (GC). However, beyond fueling GC cell anabolism, its role in remodeling the immunosuppressive tumor microenvironment remains poorly understood. Here, we show that GC cells overexpress solute carrier family 1 member 5 (SLC1A5) to drive glutamine accumulation, which not only promotes their own proliferation but also reduces glutamine availability to CD8+ T cells, thereby suppressing antitumor immunity. These dual effects cooperatively drive GC progression. Mechanistically, loss of methyltransferase‐like protein 7A (METTL7A) stabilizes SLC1A5 mRNA by reducing its m6A modification. Concurrently, METTL7A deficiency increased N‐glycosyltransferase β‐1,4‐galactosyltransferase 5 (B4GALT5) expression. B4GALT5 stabilizes SLC1A5 via N‐glycosylation at the N212 site, which blocks K48‐linked polyubiquitination and proteasomal degradation. We identify the natural flavonoid luteolin as an agent that upregulates METTL7A expression, which subsequently downregulates SLC1A5 expression and inhibits GC progression. Furthermore, luteolin significantly enhances the efficacy of anti‐PD‐1 therapy in GC. Collectively, our findings reveal that SLC1A5‐mediated glutamine competition drives both tumor cell proliferation and immune evasion in GC, and suggest that targeting the METTL7A/SLC1A5 axis may represent a promising therapeutic strategy.
Mingjun Sun, Shuwei Dang, Dazhi Zhou et al.· Advancement of science· 0 citations
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