氧化低密度脂蛋白功能性调节人内皮细胞的生长调节致癌基因α

目的　探讨oxLDL对人内皮细胞的CXC亚家族趋化因子GROα的调节作用及生理意义。方法　超高速离心得LDL ,氧化后得oxLDL。逆转录PCR分析人内皮细胞系ECV30 4细胞GROαmRNA。GAPDH被用作PCR中正常改变的对照物。酶联免疫检测仪测定ECV30 4细胞表面连接及分泌到溶液中的GROα蛋白。静态细胞粘附试验测定ECV30 4细胞表面连接的GROα蛋白的生理意义。结果　正常ECV30 4细胞不表达GROαmRNA ;OxLDL显著调节其表达 ,诱导效应首先出现在处理后 1h ,最大在 2h ,在 4h时下降。相比较 ,LDL对其mRNA表达没有影响。正常ECV30 4细胞低水平表达细胞表面的GROα蛋白。OxLDL呈浓度依赖性、时间依赖性地上调其表面的GROα蛋白。相比较 ,LDL对其表面表达的GROα蛋白无调节作用。OxLDL对ECV30 4细胞分泌到细胞溶液中GROα蛋白很少有影响。 4 0 μg/mloxLDL处理ECV30 4细胞 2 4h ,造成显著的人单核细胞系U937细胞粘附到ECV30 4细胞数目的增加。用GROα抗体预处理oxLDL刺激的ECV30 4细胞 ,可显著减低U937细胞粘附到ECV30 4细胞的U937细胞数目 (大约 2 / 3)。结论　oxLDL可能功能性上调内皮细胞GROα的表达。     

Experimental Obstructive Jaundice Results in Oxidized Low-Density-Lipoprotein Accumulation in Surgical Wound of Rats

Introduction : Mounting evidence suggests that impaired wound healing is a well-defined consequence in obstructive jaundice and, as redox-regulated processes are relevant to wound healing, it is not unreasonable to suppose that oxidative stress associated with lipid peroxidation in cholestasis might be a systemic phenomenon probably comprising all tissues and organs, including wounds. The aim of the present investigation was to analyse the lipid peroxidation status of surgical wounds, in terms of oxidized low-density-lipoprotein (oxLDL) accumulation in experimental obstructive jaundice.

Methods : Sixteen Wistar-Albino rats weighing 200–230 gr were randomly divided into two groups. Group I (n = 8) was designed as the prolonged obstructive jaundice group and was subjected to bile duct ligation. Group II (Sham-control, n = 8) rats underwent laparotomy alone and bile duct was just dissected from the surrounding tissue. Histopathological evaluation, immunohistochemical screening and immunoflourescent staining of the surgical wound was conducted to the bile-duct ligated rats and control group on the 21^st postoperative day.

Results : Wound healing was found to be impaired in jaundiced rats histopathologically. When compared with the control group, significant positive oxLDL staining and intracellular accumulation of TNF-a, IL-2 and iL-6 was detected in the wound sections of the prolonged obstructive jaundice group.

Conclusion : Our present data is the first in the literature, indicating significant oxLDL accumulation in surgical wounds of cholestatic rats, which might be one of the results of systemic oxidative stress leading to deficient healing capacity as a consequence of persistent inflammation.     

冠心病不同类型间斑块稳定性相关指标的比较研究

目的　比较血清抗氧化低密度脂蛋白 (oxLDL)抗体、细胞间黏附分子 1(ICAM 1)、血管细胞黏附分子 1(VCAM 1)和E 选择素水平对不同类型冠心病斑块稳定性的评价意义。方法　用酶联免疫吸附法 (ELISA)检测了 10 0例冠心病患者 (17例急性心肌梗死 ,4 1例不稳定性心绞痛 ,4 2例稳定性心绞痛 )及 31例正常健康对照者血清ICAM 1、VCAM 1、E 选择素和血清抗oxLDL抗体水平 ,并比较上述各指标水平与不同类型冠心病斑块稳定性之间的关系。结果　血清ICAM 1水平在急性心肌梗死组 (76 4± 111)ng/ml和不稳定性心绞痛组 (70 9± 10 0 )ng/ml明显高于稳定性心绞痛组 (6 0 7± 83)ng/ml,和正常对照组 (6 0 3± 90 )ng/ml,P <0 0 1;血清VCAM 1水平在急性心肌梗死组 (185 5± 6 6 6 )ng/ml和不稳定性心绞痛组 (172 4± 5 5 5 )ng/ml明显高于稳定性心绞痛组 (136 0± 36 0 )ng/ml,和正常对照组 (10 39± 319)ng/ml,P <0 0 1;血清E 选择素水平在急性心肌梗死组 (5 4± 19)ng/ml和不稳定性心绞痛组 (5 3± 2 2 )ng/ml明显高于稳定性心绞痛组 (39± 19)ng/ml,和正常对照组 (38± 14 )ng/ml,P <0 0 5 ;血清抗oxLDL抗体水平在急性心肌梗死组 (1 39± 0 6 8)和不稳定性心绞痛组 (1 35± 0 6 2 )明显高于稳定性心绞痛组 (0     

'Danger' effect of low-density lipoprotein (LDL) and oxidized LDL on human immature dendritic cells

Dendritic cell (DC) maturation may accelerate autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis, and may contribute to accelerated atherosclerosis seen in these patients. The immune system responds to both exogenous and endogenous 'dangerous' signals that can induce dendritic cell maturation. We have found that autologous plasma contains danger signals that induce up-regulation of major histocompatibility complex (MHC) class II and co-stimulatory molecules in immature DCs (iDCs). The objective of this study was to determine whether low-density lipoprotein (LDL) and/or oxidized LDL (oxLDL) constitute danger signals, and to assess the effect of exposure to LDL and oxLDL following monocyte differentiation into iDCs in lipoprotein-deficient serum (LPDS). IDCs were generated in the presence of autologous plasma or LPDS. Expression of maturation and migration molecules was evaluated using flow cytometry, and morphology was assessed by light microscopy. Pro- or anti-apoptotic effect was determined using annexin V and propidium iodide binding. Phagocytosis of apoptotic cells was evaluated using autologous plasma or LPDS. LDL and oxLDL were clearly able to slightly up-regulate levels of HLA-DR and co-stimulatory molecule CD86. High oxLDL concentrations (50-100 microg/ml) were associated with expression of additional maturation molecules. Moreover, iDCs that were prepared in LPDS showed partial maturation following exposure to LDL and oxLDL, and improved tolerogenic apoptotic cell uptake. This study suggests that oxLDL, and to some extent LDL, are at least partly responsible for the iDC 'danger' response induced by autologous plasma.     

HRD1在oxLDL刺激的人脐静脉血管内皮细胞中的表达及意义

目的:观察羟甲基戊二酰辅酶A还原酶降解蛋白1(HMG-CoA reductase degradation protein 1,HRD1)在人脐静脉血管内皮细胞(human umbilical vein endothelial cells,HUVEC)内的表达情况,探讨HRD1对氧化型低密度脂蛋白(oxidized low density lipoprotein,oxLDL)引起的血管内皮细胞凋亡及细胞内脂质沉积的影响?方法:免疫荧光检测HRD1在动脉粥样硬化患者血管组织中的表达?同时体外传代培养HUVEC,oxLDL刺激细胞后Western blot法观察HRD1的表达情况?Ad-HRD1感染oxLDL刺激后的HUVEC,Western blot法观察HRD1对细胞凋亡的影响,油红O染色法观察HRD1对细胞内脂滴生成的影响?结果:HRD1表达于动脉粥样硬化患者血管组织中;也表达于oxLDL刺激后的HUVEC中;Ad-HRD1感染oxLDL刺激后的HUVEC,Cleaved PARP和Cleaved Caspase 3表达降低并且细胞内脂滴形成减少?结论:HRD1可抑制oxLDL导致的内皮细胞凋亡和细胞内脂质沉积?     

Enzymatically modified low-density lipoprotein upregulates CD36 in low-differentiated monocytic cells in a peroxisome proliferator-activated receptor-gamma-dependent way

Peroxisome proliferator-activated receptor-gamma (PPARgamma) has been suggested to upregulate CD36. Since free oxidized polyunsaturated fatty acids are PPARgamma ligands, we studied the effects of LDL modified by the simultaneous action of sPLA2 and 15-lipoxygenase (15LO) on CD36 expression and PPARgamma activation in monocytic cells. Exposure of MM6 cells, which do not express CD36 or other scavenger receptors, to such enzymatically modified LDL (enzLDL) resulted in upregulation of CD36 surface protein and mRNA expression. Similar effects were observed with free 13-hydroperoxyoctadecadienoic acid but not its esterified counterpart. Less pronounced effects were observed with LDL modified by 15LO alone. Upregulation of CD36 was inversely correlated to the state of cell differentiation, as showed by lower response to enzLDL of the scavenger receptor-expressing MM6-sr and THP1 cells. Importantly, LDL modified by sPLA2 and 15LO did not efficiently induce upregulation CD36 in PPARgamma-deficient macrophage-differentiated embryonic stem cells confirming a role of PPARgamma in CD36 expression in cells stimulated with enzLDL. Our data show that LDL modified with physiologically relevant enzymes stimulates CD36 expression in non-differentiated monocytes and that this process involves PPARgamma activation. These effects of enzLDL can be considered pro-atherogenic in the context of early atherosclerosis.     

Cholesterol crystallization and macrophage apoptosis: implication for atherosclerotic plaque instability and rupture

The presence of abundant cholesterol crystals symbolizes the disorder of cholesterol metabolism during the development of atherosclerosis. Examination of cultured human THP-1 macrophages treated with the cholesterol oxide, 7-ketocholesterol, revealed a concentration- and time-dependent increase in formation of cholesterol crystals in the cells. Radioisotope labeling and X-ray diffraction confirmed the presence of 7-ketocholesterol crystalline domains (d space 35.8A). Under the normal cell culture condition (5% CO(2), 37 degrees ), incubation with 7-ketocholesterol induced moderate levels of apoptosis. Elevating temperature from 37 to 40 degrees markedly reduces formation of the crystals in the macrophages. Meanwhile, at high temperatures, significantly increased numbers of apoptotic cells were detected in the cells treated with 7-ketocholesterol but not in those with native free cholesterol. These results suggest that hyperthermia inhibits cholesterol crystallization and promotes apoptotic effects of oxysterols on macrophages.     

Interleukin-25 reduces Th17 cells and inflammatory responses in human peripheral blood mononuclear cells

Background

The absence of interleukin-25 (IL-25) favors the induction of Th1 and Th17 immune responses in mice. Th1 immune responses have been associated with the pathology of atherosclerosis, a lipid and inflammation driven disease of the arterial wall.