活化蛋白C对系统性红斑狼疮患者表达CC趋化因子配体2的影响

The effect of activated protein C on the expression of CC chemokine ligand 2 in patients with systemic lupus erythematosus

目的探讨活化蛋白C(APC)及其可溶性内皮细胞蛋白C受体(sEPCR)是否通过调控CC趋化因子配体2(CCL2)表达而对SLE的病情活动程度产生影响。方法采用ELISA法检测94例SLE患者及35名健康对照者血浆中APC、sEPCR和CCL2水平,并对APC、sEPCR与SLEDAI及CCL2表达水平的相关性进行分析。同时采用细胞体外培养方法观察重组APC对CCL2表达和对NF-κB信号通路的作用。正态分布的2组计量资料采用t检验,非正态分布的2组计量资料采用Mann-whitney U检验,2组计量资料的相关性采用Pearson相关性分析。结果血浆APC水平在SLE患者虽有升高,但与对照组比较差异无统计学意义[475.55(205.03,964.90)ng/ml和398.50(216.60,835.32)ng/ml,Z=0.221,P=0.825],而sEPCR水平则明显升高[(215±104)ng/ml和(127±73)ng/ml,t=4.734,P<0.01],导致SLE患者的APC/sEPCR比率明显下降[2.4(0.9,4.7)和4.2(2.2,8.5),Z=3.212,P=0.001];CCL2水平在SLE患者为[543.45(285.48,1216.25)pg/ml],明显高于健康对照组[173.5(109.825,300.30)pg/ml,Z=5.801,P<0.01]。相关性分析结果显示:SLE患者APC/sEPCR比率下降的程度与SLEDAI(r=-0.245,P=0.016)及CCL2表达水平(r=-0.262,P=0.012)呈负相关。体外实验结果表明APC以剂量依赖性方式抑制脂多糖刺激的单核细胞株人外周血的单核细胞系(THP)-1表达CCL2,并伴随NF-κB DNA结合活性水平的受抑,这一作用可被蛋白C抑制剂拮抗。结论APC/sEPCR比率与SLEDAI相关性联系,提示其可作为SLE病情活动的判断指标。APC可通过抑制NF-κB的活性来下调CCL2的表达,而sEPCR在SLE中的过度表达,使得APC这一抗炎作用减弱,可能与蛋白C系统对SLE病情活动程度的影响有关。

Objective To investigate whether activated protein C(APC)and soluble endothelial cell protein C receptor(sEPCR)affected the disease activity of systemic lupus erythematosus(SLE)by regulating the expression of CC chemokine ligand 2(CCL2).Methods Ninety-four patients with SLE and 35 healthy subjects matched for gender and age were recruited.The plasma levels of APC,sEPCR and CCL2 were detected by enzyme-linked immuno sorbent assay(ELISA),and the correlation of APC,sEPCR and APC/sEPCR ratio with systemic lupus erythematosus disease activity index(SLEDAI)or CCL2 levels was then analyzed.In vitro study was employed to investigate the effects of APC on CCL2 expression and NF-κB DNA binding activity in lipopolysaccharide(LPS)-stimulated THP-1 cells.Statistical analysis was conducted by unpaired Student's t-test,Mann-Whitney U test,and Spearman's correlation analysis.Results In SLE patients,plasma APC level increased slightly as compared with that in the control group[475.55(205.03,964.90)ng/ml vs 398.50(216.60,835.325)ng/ml,Z=0.221,P=0.825],while plasma sEPCR level increased significantly[(215±104)ng/ml vs(127±73)ng/ml,t=4.734,P<0.01],resulting in a markedly decreased APC/sEPCR ratio[2.4(0.9,4.7)vs 4.2(2.2,8.5),Z=3.212,P=0.001].CCL2 level was shown to be markedly higher in SLE patients than that of control[543.45(285.48,1216.25)pg/ml vs 173.5(109.825,300.30)pg/ml,Z=5.801,P<0.01].In addition,APC/sEPCR ratio was inversely correlated with SLEDAI(r=-0.245,P=0.016)as well as CCL2 level(r=-0.262,P=0.012)in patients with SLE.Moreover,the expression of CCL2 in LPS-stimulated THP-1 cells was inhibited by APC treatment in vitro,paralleled with the reduction of NF-κB DNA binding activity.Conclusion The anti-inflammatory function of APC,demonstrated by down-regulating CCL2 expression through inhibiting NF-κB DNA binding activity,is impaired by the over expression of sEPCR in patients with SLE,and thus results in high CCL2 level found in SLE patients.The correlation of APC/sEPCR ratio with SLEDAI indicates that APC/sEPCR ratio may be an indicator for SLE activity.