Background： Adipocytes behave like a rich source of pro-inflammatory cytokines including monocyte chemoattractant protein- 1 （MCP- 1）. Oxidized low-density lipoprotein （oxLDL） participates in the local chronic in...Background： Adipocytes behave like a rich source of pro-inflammatory cytokines including monocyte chemoattractant protein- 1 （MCP- 1）. Oxidized low-density lipoprotein （oxLDL） participates in the local chronic inflammatory response, and high-density lipoprotein could counterbalance the proinftammatory function of αLDL, but the underlying mechanism is not completely understood. This study aimed to evaluate the effect of apolipoprotein A-I mimetic peptide L-4F on the secretion and expression of MCP-1 in fully differentiated 3T3-L 1 adipocytes induced by oxLDL and to elucidate the possible mechanisms. Methods： Fully differentiated 3T3-L 1 adipocytes were incubated in the medium containing various concentration of L-4F （0-50 gg/ml） with oxLDL （50 Lag/ml） stimulated, with/without protein kinase A （PKA） inhibitor H-89 （10 gmol/L） preincubated. The concentrations of MCP- 1 in the supematant, the mRNA expression of MCP- 1, the levels of CCAAT/enhancer binding protein α （C/EBPα）, and CCAAT/ enhancer binding protein 13 （C/EBPβ） were evaluated. The monocyte chemotaxis assay was performed by micropore filter method using a modified Boyden chamber. Results： OxLDL stimulation induced a significant increase ofMCP-1 expression and secretion in 3T3-L 1 adipocytes, which were inhibited by L-4F preincubation in a dose-dependent manner. PKA inhibitor H-89 markedly reduced the oxLDL-induced MCP-1 expression, but no further decrease was observed when H-89 was used in combination with L-4F （50 μg/ml） （P 〉 0.05）. OxLDL stimulation showed no significant effect on C/EBPa protein level but increased C/EBPβ protein level in a time-dependent manner. H-89 and L-4F both attenuated C/EBPI3 protein level in oxLDL-induced 3T3-L1 adipocytes. Conclusions： OxLDL induces C/EBPI3 protein synthesis in a time-dependent manner and enhances MCP-1 secretion and expression in 3T3-L 1 adipocytes. L-4F dose-dependently counterbalances the pro-inflammatory effect of oxLDL, and cyclic AMP/PKA-C/EBP-β sign展开更多
目的探讨硫酸脱氢表雄酮(DHEA-S)对3T3-L1前脂肪细胞株分化的影响及可能的分子机制。方法以3T3-L1细胞株为研究对象,先观察不同时间点不同剂量的DHEA-S对3T3-L1细胞活力的影响,确定合适的干预浓度。3T3-L1细胞分为DMSO组(对照组)和DHEA-...目的探讨硫酸脱氢表雄酮(DHEA-S)对3T3-L1前脂肪细胞株分化的影响及可能的分子机制。方法以3T3-L1细胞株为研究对象,先观察不同时间点不同剂量的DHEA-S对3T3-L1细胞活力的影响,确定合适的干预浓度。3T3-L1细胞分为DMSO组(对照组)和DHEA-S组,观察DHEA-S对3T3-L1前脂肪细胞分化的影响。通过测定甘油醛3-磷酸脱氢酶(G3PDH)活性和用油红O染色计算的脂肪细胞分化率,评估脂肪细胞分化的变化;用real time-PCR法观察诱导前(第0天)和诱导后不同时间点(第1,2,4,6,10,14天)目的基因过氧化物酶体增殖物激活受体-γ(PPARγ)、固醇调节元件结合蛋白-1c(SREBP1-c)、CCAAT增强子结合蛋白家族(C/EBPs)、11β-羟类固醇脱氢酶1(11HSDB1)、激素敏感性脂肪酶(HSL)和脂蛋白酯酶(LPL)mRNA表达的变化。结果MTT实验结果显示DHEA-S在50μmol/L时对细胞活力影响<30%,对后续的干预影响较小。分化后第4天对照组和DHEA-S组的G3PDH活性分别为(380.83±28.43)nmol/(min·mg)和(253.07±27.67)nmol/(min·mg),分化后第10天对照组和DHEA-S组的G3PDH活性为(573.93±17.5)nmol/(min·mg)和(398.17±24.05)nmol/(min·mg),差异均具有统计学意义(P<0.01)。油红O染色计算脂肪细胞分化率对照组和DHEA-S组在诱导后第4天分别为39.09%±5.51%和15.66%±0.75%,第10天分别为78.82%±3.37%和49.09%±9.75%,差异也有统计学意义(P<0.01)。real time PCR检测结果显示,DHEA-S显著抑制脂肪细胞分化相关的关键基因(PPARγ、ADD1/SREBP1-c、C/EBPs、11HSDB1、LPL和HSL)mRNA的表达。结论DHEA-S(50μmol/L)在体外可能通过抑制11HSDB1的表达,减少局部活性皮质醇,进而下调其他脂肪细胞分化的关键基因,抑制3T3-L1细胞的分化。展开更多
基金This work was supported by grants from the National Natural Science Foundation of China （No. 30470705 and No. 81270154）.
文摘Background： Adipocytes behave like a rich source of pro-inflammatory cytokines including monocyte chemoattractant protein- 1 （MCP- 1）. Oxidized low-density lipoprotein （oxLDL） participates in the local chronic inflammatory response, and high-density lipoprotein could counterbalance the proinftammatory function of αLDL, but the underlying mechanism is not completely understood. This study aimed to evaluate the effect of apolipoprotein A-I mimetic peptide L-4F on the secretion and expression of MCP-1 in fully differentiated 3T3-L 1 adipocytes induced by oxLDL and to elucidate the possible mechanisms. Methods： Fully differentiated 3T3-L 1 adipocytes were incubated in the medium containing various concentration of L-4F （0-50 gg/ml） with oxLDL （50 Lag/ml） stimulated, with/without protein kinase A （PKA） inhibitor H-89 （10 gmol/L） preincubated. The concentrations of MCP- 1 in the supematant, the mRNA expression of MCP- 1, the levels of CCAAT/enhancer binding protein α （C/EBPα）, and CCAAT/ enhancer binding protein 13 （C/EBPβ） were evaluated. The monocyte chemotaxis assay was performed by micropore filter method using a modified Boyden chamber. Results： OxLDL stimulation induced a significant increase ofMCP-1 expression and secretion in 3T3-L 1 adipocytes, which were inhibited by L-4F preincubation in a dose-dependent manner. PKA inhibitor H-89 markedly reduced the oxLDL-induced MCP-1 expression, but no further decrease was observed when H-89 was used in combination with L-4F （50 μg/ml） （P 〉 0.05）. OxLDL stimulation showed no significant effect on C/EBPa protein level but increased C/EBPβ protein level in a time-dependent manner. H-89 and L-4F both attenuated C/EBPI3 protein level in oxLDL-induced 3T3-L1 adipocytes. Conclusions： OxLDL induces C/EBPI3 protein synthesis in a time-dependent manner and enhances MCP-1 secretion and expression in 3T3-L 1 adipocytes. L-4F dose-dependently counterbalances the pro-inflammatory effect of oxLDL, and cyclic AMP/PKA-C/EBP-β sign
文摘目的探讨硫酸脱氢表雄酮(DHEA-S)对3T3-L1前脂肪细胞株分化的影响及可能的分子机制。方法以3T3-L1细胞株为研究对象,先观察不同时间点不同剂量的DHEA-S对3T3-L1细胞活力的影响,确定合适的干预浓度。3T3-L1细胞分为DMSO组(对照组)和DHEA-S组,观察DHEA-S对3T3-L1前脂肪细胞分化的影响。通过测定甘油醛3-磷酸脱氢酶(G3PDH)活性和用油红O染色计算的脂肪细胞分化率,评估脂肪细胞分化的变化;用real time-PCR法观察诱导前(第0天)和诱导后不同时间点(第1,2,4,6,10,14天)目的基因过氧化物酶体增殖物激活受体-γ(PPARγ)、固醇调节元件结合蛋白-1c(SREBP1-c)、CCAAT增强子结合蛋白家族(C/EBPs)、11β-羟类固醇脱氢酶1(11HSDB1)、激素敏感性脂肪酶(HSL)和脂蛋白酯酶(LPL)mRNA表达的变化。结果MTT实验结果显示DHEA-S在50μmol/L时对细胞活力影响<30%,对后续的干预影响较小。分化后第4天对照组和DHEA-S组的G3PDH活性分别为(380.83±28.43)nmol/(min·mg)和(253.07±27.67)nmol/(min·mg),分化后第10天对照组和DHEA-S组的G3PDH活性为(573.93±17.5)nmol/(min·mg)和(398.17±24.05)nmol/(min·mg),差异均具有统计学意义(P<0.01)。油红O染色计算脂肪细胞分化率对照组和DHEA-S组在诱导后第4天分别为39.09%±5.51%和15.66%±0.75%,第10天分别为78.82%±3.37%和49.09%±9.75%,差异也有统计学意义(P<0.01)。real time PCR检测结果显示,DHEA-S显著抑制脂肪细胞分化相关的关键基因(PPARγ、ADD1/SREBP1-c、C/EBPs、11HSDB1、LPL和HSL)mRNA的表达。结论DHEA-S(50μmol/L)在体外可能通过抑制11HSDB1的表达,减少局部活性皮质醇,进而下调其他脂肪细胞分化的关键基因,抑制3T3-L1细胞的分化。
基金This work was supported in part by the National Basic Research Priorities Programme of China (No. 2002CB512806)the National Natural Science Foundation of China (No. 90408009, 30370592)International Collaborative Items of Ministry of Science and Technology of China (No. 2003DF000038) and Science and Technology Committee of Shanghai.
