Resveratrol inhibits lipid droplet formation in 3T3-L1 cells via ESR1-PI3K signaling pathway

【Objective】To investigate the effects of resveratrol（RES）and estrogen receptor 1（ESR1）on the formation of lipid droplets in 3T3-L1 cells and their regulatory mechanisms，and to provide theoretical basis for study of the potential mechanism of RES to inhibit fat deposition.【Method】Using 3T3-L1 cells as test materials，small interfering RNA （siRNA）targeting ESR1 gene was designed and synthesized. RES was added to 3T3-L1 cell culture medium，with the addition of equal amounts of dimethyl sulfoxide（DMSO）as control，the effects of RES and ESR1 on the differentiation of 3T3-L1 cells were analyzed using oil red O staining，real-time fluorescence quantitative PCR assay and Western blotting assay.【Result】Compared with the control group，RES significantly（P<0.05）reduced the production of lipid droplets in 3T3-L1 cells，extremely significantly（P<0.001）up-regulated the relative expression of ATGL，a key gene for lipolysis， and extremely significantly（P<0.001）down-regulated the relative expression of CEBPα，PPARγ and FAS，key genes for adipogenesis. RES extremely significantly（P<0.001）increased the relative expression of ESR1 gene expression，and extremely significantly（P<0.01）increased the relative expression level of ESR1 protein；at the same time，RES extremely significantly（P<0.001）down-regulated the relative expression of PI3K and AKT genes in the PI3K signaling pathway， and extremely significantly（P<0.001）up-regulated the relative expression of FOXO1 gene. Interference with ESR1 gene extremely significantly（P<0.01）increased the generation of lipid droplets in 3T3-L1 cells，extremely significantly（P<0.001）down-regulated the relative expression of ATGL gene，and extremely significantly（P<0.001）up-regulated the relative expression of CEBPα，PPARγ and FAS genes；after the addition of RES，the lipid droplets of 3T3-L1 cells interfering with ESR1 gene were not significantly different（P>0.05，the same below）compared with those without RES. There was no significant difference in the relative expression of ATGL，CEBPα，PPARγ and FAS genes. Interfering with ESR1 gene could extremely significantly（P<0.001）up-regulate the relative expression of PI3K and AKT genes in the PI3K signaling pathway，and extremely significantly（P<0.001）down-regulate the relative expression of FOXO1 gene； the relative expression of PI3K，AKT and FOXO1 genes were not significantly different when RES was added compared with that of not adding RES.【Conclusion】Through the ESR1-PI3K signaling pathway，RES can up-regulate the relative expression of ATGL，the key gene of lipolysis，and down-regulate the relative expression of CEBPα，PPARγ and FAS，the key genes of fat synthesis，thereby inhibiting the formation of lipid droplets in 3T3-L1 cells.