Nuciferine Inhibited the Differentiation and Lipid Accumulation of 3T3-L1 Preadipocytes by Regulating the Expression of Lipogenic Genes and Adipokines

Abstract

Purposes: Nuciferine, a main aporphine alkaloid component found in lotus leaf (Nelumbo nucifera), has been demonstrated to possess the property of reducing fat mass and alleviating dyslipidemia in vivo. The purpose of this study is to explore the effects of nuciferine on the proliferation and differentiation of 3T3-L1 cells and further investigate the possible underlying molecular mechanisms.Methods: 3T3-L1 preadipocytes were treated with 0∼20 μM nuciferine for 24∼120 h, the cell viability was assessed using CCK8. 3T3-L1 preadipocytes and human primary preadipocytes were then induced differentiation and the effects of nuciferine on the lipid metabolism in differentiating and fully differentiated adipocytes were observed by the methods of intracellular triglyceride (TG) assay, Oil Red O staining, RT-qPCR and western blot. Transient transfection and dual luciferase reporter gene methods were used to assess the effects of nuciferine on FAS promoter activities.Results: Nuciferine inhibited the proliferation of 3T3-L1 preadipocytes in a dose- and time-dependent manner. 20 μM nuciferine significantly attenuated lipid accumulation and reduced intracellular TG contents by 47.2, 59.9 and 55.4% on the third, sixth and ninth day of preadipocytes differentiation, respectively (all p < 0.05). Moreover, the mRNA levels of PPARγ, C/EBPα, C/EBPβ, FAS, ACC, HSL and ATGL were notably decreased by 39.2∼92.5% in differentiating preadipocytes when treated with 5∼20 μM nuciferine (all p < 0.05). In fully differentiated adipocytes treated with 20 μM nuciferine for 48 h, the mRNA levels of FAS, ACC and SREBP1 were remarkably downregulated by 22.6∼45.2% compared with the controls (0 μM) (all p < 0.05), whereas the expression of adipokines FGF21 and ZAG were notably promoted by nuciferine. Similarly, in fully differentiated human primary adipocytes, the mRNA levels of FAS, ACC, SREBP1 were decreased and the expression of FGF21 and ZAG were elevated after treated with nuciferine (all p < 0.05). Further mechanism studies showed that 2.5∼20 μM nuciferine significantly decreased FAS promoter activities in 3T3-L1 preadipocytes.Conclusion: Nuciferine inhibited the proliferation and differentiation of 3T3-L1 preadipocytes. The inhibitory effects of nuciferine on adipogenesis might be due to the downregulation of PPARγ, C/EBPα and C/EBPβ, which led to the reduction of intracellular lipid accumulation in 3T3-L1 cells and by downregulating the expression of critical lipogenic enzymes, especially of FAS, which was achieved by inhibiting the FAS promoter activities. Besides, nuciferine promoted the expression of adipokines in fully differentiated adipocytes.

Medicinal and edible plants in the treatment of dyslipidemia: advances and prospects

“…In vitro, nuciferine can decrease the intracellular TG content and inhibit the proliferation, differentiation, lipid accumulation and adipogenesis of 3T3-L1 preadipocytes. The lipid metabolism related genes PPARγ, SREBP-1, C/EBPα, C/EBPβ, FAS, ACC, and ATGL were involved in this metabolic regulation [138]. Besides, nuciferine contributes to attenuating foam cell formation and atherosclerosis.…”

Natural Aporphine Alkaloids with Potential to Impact Metabolic Syndrome

“…In fully differentiated human primary adipocytes, nuciferine also decreases FAS, ACC, and SREBP1 at mRNA levels. Notably, it reduces FAS promoter activity, which is consistent with its reduction in intracellular lipid accumulation and down-regulation of critical lipogenic enzymes in 3T3-L1 preadipocytes [ 31 ]. Furthermore, both nuciferine and pronuciferine significantly decrease lipid droplets and intracellular TC content in insulin resistant 3T3-L1 adipocytes, showing the amelioration of lipid metabolism [ 10 ].…”

“…Adipokine zinc-alpha2-glycoprotein (ZAG) is a potent lipid-mobilizing factor. Nuciferine promotes FGF21 and ZAG expression in fully differentiated adipocytes [ 31 ]. A negative correlation between oxidative stress and adiponectin (an adipokine) is observed in patients with metabolic syndrome.…”

Alkaloids from lotus (Nelumbo nucifera): recent advances in biosynthesis, pharmacokinetics, bioactivity, safety, and industrial applications

“…[FAS]) (Xu et al 2021). The inhibitory effects of nuciferine on adipocyte differentiation may be attributed to its suppression of the protein kinase B (AKT)mechanistic target of the rapamycin complex (mTORC1) pathway (Yoo et al 2019).…”