| 摘要: | 本研究探討aryl hydrocarbon receptor (AhR) 之antagonist α-naphthoflavone (α-NF)及AhR agonist indole-3-carbinol (I3C)於成熟脂肪細胞及其相關血管新生作用影響，由於成熟脂肪細胞大多存在肥胖者體內，故使用成熟脂肪細胞作為實驗模式。將3T3-L1前脂肪細胞誘發分化後，再投與α-NF及I3C，觀察對於成熟脂肪脂質堆積及成熟脂肪細胞誘發類血管生成所扮演之角色。結果顯示α-NF可促進成熟脂肪細胞之脂質堆積與成熟脂肪細胞condition medium (CM) 誘導之類血管生成作用，伴隨成熟脂肪細胞中AhR、ARNT、CYP1B1及Nrf-2蛋白質表現降低及促進HSL、ER蛋白質表現，且成熟脂肪細胞之CM中VEGF與 IL-6生成增加，與NO、IGF-1、MMP-2及MMP-9表現下降。而I3C則為抑制脂肪細胞之脂質堆積與類血管生成作用，伴隨促進AhR、ARNT及CYP1B1蛋白質表現與降低及GPDH、HSL與Nrf-2蛋白質表現，且CM中甘油、IGF-1、VEGF、IL-6與NO生成量降低，且MMP-2及MMP-9活性表現受抑制。此外以siRNA將AhR knockdown，可促進脂肪細胞脂質堆積、VEGF及NO生成，並降低甘油釋出與IL-6釋出。本研究發現AhR antagonist α-NF促進成熟脂肪細胞之脂質堆積與類血管生成，AhR agonist I3C則抑制此作用而與α-NF呈現相反結果，且抑制AhR可增加脂肪細胞分化之脂質生成與相關血管新生因子釋出。因此AhR可抑制脂肪細胞分化及已分化脂肪細胞之脂質堆積與其誘發之類血管生成作用，顯示AhR具有預防或治療肥胖相關疾病之作用。
The objective of this study was to investiagte the aryl hydrocarbon receptor (AhR) antagonist, α-naphthoflavone (α-NF), and AhR agonist, indole-3-carbinol (I3C), a compound derived from cruciferous vegetables, on lipid accumulation and angiogenesis in cultured adipocytes. In these studies, 3T3-L1 preadipocytes were differentiated to mature adipocytes, which were then treated with different concentrations of α-NF or I3C. The condition medium (CM) from mature adipocytes was collected for tube formation analysis in EA hy926 human vascular endothelial cells to identify angiogenesis. Results showed that α-NF enhanced the lipid droplet accumulation, triglyceride (TG) contents, hormone-sensitive lipase (HSL), vascular endothelial growth factor receptor (VEGFR) and estrogen receptor (ER) protein expressions in adipocytes, but aryl hydrocarbon receptor nuclear translocator (ARNT), cytochrome P450 1B1 (CYP1B1), nuclear factor erythroid 2-related factor 2 (Nrf-2) and glycerol-3-phosphate dehydrogenase (GPDH) protein expressions were decreased by α-NF treatment. Moreover, CM collected from differentiated adipocytes induced tube formation in Eahy926 vascular endothelial cells, but angiogenesis-realted factors, such as NO, IGF-1 and MMP-2,-9 were inhibited by α-NF, and VEGF and IL-6 levels were enhanced. On the other hand, I3C inhibited lipid droplet accumulation, TG contents, IGF-1 release, Nrf-2, HSL, GPDH and VEGFR protein expressions. Glycerol release, AhR, ARNT and CYP1B1 protein expression were increased by I3C treatment. I3C also decreased CM induced tube formation, and the effects were associated with inhibition of MMP-2, MMP-9 activities, VEGF, NO and IL-6 release. These data were indicated I3C have opposite results from α-NF, except for MMP activity, IGF-1 and NO secretion, and Nrf-2 protein expression. Furthermore, AhR knockdown by siRNA enhanced higher lipid accumuation, VEGF and NO secretion but lower glycerol and IL-6 release than non-knockdown mature adipocytes. In conclusion, α-NF enhanced lipid accumulation, mature adipocytes CM-induced tube formation, whereas I3C exhibited opposite effects. These effects are associated with modulation of adipogenic factors and angiogenic factors expression. AhR knockdown increased lipid accumuation and angiogenic factors in adipocyte differentiaion. AhR may pose dual roles in preventing and remedying of obesity and its related disease. |
