Nuciferine Prevents Obesity by Inhibiting Macrophage Inflammation Involving LGALS3, CTSB, and RBP4 Genes Based on an Integrative Analysis of Adipose Tissue Transcriptomics and Network Pharmacology

INTRODUCTION: Nuciferine, the key aporphine alkaloid compound extracted from lotus leaf, has demonstrated remarkable effects in the prevention of obesity. Our current study sought to elucidate the exact mechanisms of the protective roles of nuciferine on obesity and associated metabolic abnormalities. METHODS: Male C57BL/6J mice were given a high-fat diet (HFD) containing 0.10% nuciferine for 12 weeks. Body weight and epididymal white adipose tissue (eWAT) mass were collected. Intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (IPITT) were conducted. A multidisciplinary approach, including transcriptomic analysis and network pharmacology, was employed to identify novel targets and signaling pathways of nuciferine in obesity prevention, which were further confirmed using real-time quantitative polymerase chain reaction (RT-qPCR), molecular docking, and in vitro cell experiments performed in RAW 264.7 macrophages. RESULTS: Nuciferine dramatically reduced the weight gain and eWAT mass and ameliorated glucose tolerance, insulin sensitivity, and inflammation in adipose tissue of HFD-fed mice. In fully differentiated 3T3-L1 adipocytes, nuciferine prevented palmitic acid (PA)-induced intracellular lipid accumulation, as evidenced by Oil Red O staining and triglyceride (TG) determination. Integration of transcriptomic sequencing in eWAT and network pharmacology identified 15 target genes, including LGALS3, CTSB, and RBP4, and 5 signaling pathways, including cAMP and Rap1 signaling pathways, which were primarily associated with inflammation. Further studies confirmed that nuciferine decreased LGALS3, CTSB, and RBP4 mRNA expression in eWAT of HFD-fed mice. Additionally, nuciferine inhibited mRNA expression of pro-inflammatory cytokines IL-6, along with LGALS3, CTSB, and RBP4 in lipopolysaccharide-treated RAW 264.7 macrophages. Molecular docking showed that nuciferine had strong binding ability to LGALS3, CTSB, and RBP4. CONCLUSION: These findings suggest that nuciferine may reduce adipose tissue inflammation by inhibiting mRNA levels of macrophage inflammation-associated genes LGALS3, CTSB, and RBP4, thereby protecting against obesity and associated metabolic inflammation.