不同高级结构墨西哥海参岩藻聚糖硫酸酯调控脂肪细胞分化的构效关系

Structure-Activity Relationship of Fucoidans from Holothuria mexicana with Different Advanced Structures that Modulate Adipocyte Differentiation

海参岩藻聚糖硫酸酯(sea cucumber fucoidan,SC-FUC)是海参体壁中的重要活性成分之一。研究表明多糖的生物活性与其高级结构密切相关。本实验旨在研究体外水平下不同高级结构墨西哥海参岩藻聚糖硫酸酯(fucoidan from Holothuria mexicana,Hm-FUC)对脂肪细胞分化活性的影响,以期为SC-FUC的更高效利用及深入开发提供理论依据。本实验以3T3-L1前脂肪细胞为研究对象,采用"传统鸡尾酒法"建立脂肪细胞分化模型,通过四甲基偶氮唑盐法、油红O染色法和逆转录实时荧光定量聚合酶链式反应法系统研究不同高级结构Hm-FUC对3T3-L1前脂肪细胞分化过程的调控作用及其分子机制。结果表明:4种Hm-FUC均可显著抑制3T3-L1细胞的增殖和分化,减少成熟脂肪细胞数目,降低细胞内甘油三酯含量;显著下调脂肪细胞分化关键转录调控因子SREBP1c、PPARγ、C/EBPα的mRNA表达(P<0.05);显著上调Wnt/β-catenin信号通路关键基因LRP5、LRP6、Frz、β-catenin、cmyc、Cyclin D1的mRNA表达(P<0.05),显著下调负调控因子GSK3β的mRNA表达(P<0.05),其中Hm3(210 kDa,无规卷曲短链构象)效果最为显著,但对Wnt10b mRNA表达无显著影响。综上所述,Hm-FUC是通过激活Wnt/β-catenin信号通路,下调脂肪细胞分化关键转录因子的表达从而抑制成脂,其中当分子质量为210 kDa,链构象为无规卷曲短链状时,其抑制脂肪细胞分化活性最强。

Sea cucumber fucoidan(SC-FUC)is one of the important bioactive components in the body wall of sea cucumber.Previous studies have shown that the biological activity of polysaccharides is closely related to their advanced structure.However,there are few reports on the association between the advanced structure of SC-FUC and its inhibitory activity against adipocyte differentiation.This work studied the effect of fucoidan from Holothuria mexicana(Hm-FUC)with different advanced structures on adipocyte differentiation,aiming to provide a theoretical basis for efficient utilization and development of SC-FUC.3T3-L1 preadipocytes were differentiated into adipocytes by using the traditional cocktail method.The regulatory effect and molecular mechanism of Hm-FUC with different advanced structures on the differentiation of 3T3-L1 preadipocytes were studied by methyl thiazolyl tetrazolium assay,Oil Red O staining and reverse transcription real-time polymerase chain reaction.The results showed that all four Hm-FUCs tested significantly inhibited the proliferation and differentiation of 3T3-L1 preadipocytes,reduced the number of mature adipocytes,and decreased intracellular triglyceride levels.Moreover,they significantly downregulated the mRNA expression of crucial transcription factors regulating adipocyte differentiation such as SREBP1c,PPARγ,and C/EBPα(P<0.05),upregulated the mRNA expression of key genes in the Wnt/β-catenin signaling pathway such as LRP5,LRP6,Frz,β-catenin,cmyc and Cyclin D1,and downregulated the mRNA expression of the negative regulatory factor GSK3β(P<0.05),with Hm3(210 kDa,with random coil short-chain configuration)showing the most significant effect.However,these Hm-FUCs showed no significant impact on the mRNA expression of Wnt10b.It is suggested that Hm-FUC could inhibit adipogenesis via activating the Wnt/β-catenin signaling pathway to downregulate the mRNA expression of the key transcription factors involved in adipocyte differentiation.Notably,the polysaccharide with molecular mass of 210 kDa and random coil short-chain configuration had the strongest inhibitory activity against adipocyte differentiation.