Objective To investigate the effects of insulin-like growth factor-1 （IGF-1） and oxidized low density lipoprotein （oxLDL） on expression ofphosphatase PHLPP 1 in vascular smooth muscle cells （VSMCs）. Methods Rabb...Objective To investigate the effects of insulin-like growth factor-1 （IGF-1） and oxidized low density lipoprotein （oxLDL） on expression ofphosphatase PHLPP 1 in vascular smooth muscle cells （VSMCs）. Methods Rabbit aortic VSMCs were cultured. VSMCs proliferation ability was determined by measuring cell number and mitochondrial dehydrogenase （MD） activity with MTT assay. Western blot was used to detect the protein expression ofphosphatase PHLPP1. Results IGF-1 （100ug/L） increased cell number and MD activity to 3.02 and 3.59 times of that in control group, oxLDL（501xg/ml） elevated the above two parameters to 2.03 and 2.91 times respectively. Western blot showed that IGF-1 and oxLDL inhibited the expression of PHLPPI to 39.27% and 40.26% of the control group （P〈0.01 ）. Conclusion IGF- 1 and oxLDL may enhance the proliferation of VSMCs by decreasing the expression ofphosphatase PHLPP 1.展开更多
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 signaling pathway may participate in it.展开更多
氧化低密度脂蛋白(oxidized low density lipoprotein,oxLDL)被认为是动脉硬化的关键致病因素。文章综合运用紫外吸收光谱、荧光光谱、同步荧光光谱及圆二色(circular dichroism,CD)光谱研究了Cu2+诱导不同时间的LDL体外氧化过程。随着...氧化低密度脂蛋白(oxidized low density lipoprotein,oxLDL)被认为是动脉硬化的关键致病因素。文章综合运用紫外吸收光谱、荧光光谱、同步荧光光谱及圆二色(circular dichroism,CD)光谱研究了Cu2+诱导不同时间的LDL体外氧化过程。随着氧化时间的增加,生成的丙二醛(malonaldehyde,MDA)的量逐渐增加,其相对应的430nm处的荧光强度也随之加强,氧化过程中生成了新的氧化产物。氧化低密度脂蛋白紫外吸收增强;表征氨基酸残基信息的特征荧光强度和同步荧光强度降低;载脂蛋白B-100(apolipoprotein B-100,apoB-100)α-螺旋含量减少。实验结果表明,LDL氧化过程中Cu2+不仅诱导了氧化产物的生成,而且改变了apoB-100的构象进而导致了生色基团的微环境的变化。展开更多
氧化修饰低密度脂蛋白(oxidized low density lipoprotein,oxLDL)被认为是动脉硬化的关键致病因素。oxLDL的性能与其唯一的组成蛋白——载脂蛋白B-100(apoB-100)的二级结构即构象密切相关。荧光光谱和圆二色(CD)光谱是研究蛋白质构象的...氧化修饰低密度脂蛋白(oxidized low density lipoprotein,oxLDL)被认为是动脉硬化的关键致病因素。oxLDL的性能与其唯一的组成蛋白——载脂蛋白B-100(apoB-100)的二级结构即构象密切相关。荧光光谱和圆二色(CD)光谱是研究蛋白质构象的有力手段,因此在oxLDL结构的研究中也有广泛的应用。本文综述了近年来荧光光谱和圆二色光谱在LDL氧化研究方面的应用,并对今后的研究方向做了展望。展开更多
文摘Objective To investigate the effects of insulin-like growth factor-1 （IGF-1） and oxidized low density lipoprotein （oxLDL） on expression ofphosphatase PHLPP 1 in vascular smooth muscle cells （VSMCs）. Methods Rabbit aortic VSMCs were cultured. VSMCs proliferation ability was determined by measuring cell number and mitochondrial dehydrogenase （MD） activity with MTT assay. Western blot was used to detect the protein expression ofphosphatase PHLPP1. Results IGF-1 （100ug/L） increased cell number and MD activity to 3.02 and 3.59 times of that in control group, oxLDL（501xg/ml） elevated the above two parameters to 2.03 and 2.91 times respectively. Western blot showed that IGF-1 and oxLDL inhibited the expression of PHLPPI to 39.27% and 40.26% of the control group （P〈0.01 ）. Conclusion IGF- 1 and oxLDL may enhance the proliferation of VSMCs by decreasing the expression ofphosphatase PHLPP 1.
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 signaling pathway may participate in it.
文摘氧化修饰低密度脂蛋白(oxidized low density lipoprotein,oxLDL)被认为是动脉硬化的关键致病因素。oxLDL的性能与其唯一的组成蛋白——载脂蛋白B-100(apoB-100)的二级结构即构象密切相关。荧光光谱和圆二色(CD)光谱是研究蛋白质构象的有力手段,因此在oxLDL结构的研究中也有广泛的应用。本文综述了近年来荧光光谱和圆二色光谱在LDL氧化研究方面的应用,并对今后的研究方向做了展望。
