不规则趋化蛋白在嘌呤霉素氨基核苷肾病模型中的表达

目的：检测CX3C族趋化因子不规则趋化蛋白(fractalkine,Fkn)在嘌呤霉素氨基核苷(puromycin aminonucleoside，PAN)肾病中的表达，进一步阐明肾病的发病机制，为肾病的治疗提供新的靶点。方法：从Wistar大鼠的颈静脉给予PAN，对照组给予等量生理盐水，在不同的时间点观察PAN引起的尿蛋白改变和肾脏炎性细胞浸润情况，并于第l、3、5、7、10天处死动物，制作肾组织匀浆和冰冻切片，分别用于RT-PCR和免疫组化研究，观察在：PAN注射的不同时间点肾组织中Fkn mRNA和蛋白质的表达情况；同时在体外用白介素-1β（IL-1β）刺激培养的肾小管上皮细胞观察Fkn的表达。结果：：PAN注射后第5天尿蛋白开始升高，持续增加直至第10天，同时伴有肾间质中CD4^ T细胞，CD8^ T细胞和单核／巨噬细胞的增加。RT-PCR和免疫组化均显示Fkn在第7、第10天表达升高，第3天主要分布在肾小球，以后主要在肾小管上皮细胞表达。用IL-1β刺激后1h体外培养的肾小管上皮细胞即开始表达FknmRNA，在4～6h达到高峰。结论：本文首次观察到Fkn在PAN肾病模型中表达增高，其特征为先出现于肾小球，后移行至肾小管，并早于肾组织中白细胞浸润及蛋白尿的发生。提示：Fkn可能是肾病发病和进展过程中的另一重要的相关分子。     

不同脑梗死亚型患者血清Fractalkine浓度的差异

目的：探讨不同牛津郡社区卒中项目（OCSP）亚型急性脑梗死患者血清Fractalkine（FKN）浓度的变化。方法：45例急性脑梗死患者按OCSP分型分为完全前循环梗死（TACI）组、部分前循环梗死（PACI）组、后循环梗死（POCI）组和腔隙性梗死（LACI）组。采用酶联免疫吸附法检测发病1～3d、7d、14d和28d时血清FKN浓度，比较各组间的差异。分析FKN浓度与相应时间点美国国立卫生研究院卒中量表（NIHSS）评分和3个月时Barthel指数（BI）的相关性。结果：各种亚型急性脑梗死患者血清FKN浓度均升高，TACI组最为显著；在不同时间点，血清FKN浓度变化大致为TACI〉PACI〉LACI〉POCI，与相应时间点NIHSS评分呈正相关，与3个月时BI呈负相关。结论：血清FKN浓度的变化可能提示急性脑梗死各OCSP亚型患者炎症损伤的差异，并影响神经功能缺损程度和患者3个月时的转归。     

Fractalkine expression in human renal inflammation.

Immune and inflammatory human renal disease is associated with heavy mononuclear cell infiltration. The trafficking of these cells to extravascular sites is directed by local production of chemokines. Fractalkine is the first described cell-surface anchored chemokine and has potent mononuclear cell-directed adhesion and chemotactic properties. The purpose of this study was to analyse the expression and distribution of fractalkine in human renal inflammation. In situ hybridization and immunohistochemistry were used to study renal biopsies from 15 patients with predominant glomerular inflammation (vasculitic glomerulonephritis) and 15 with predominant tubular and interstitial inflammation (acute renal allograft rejection). Controls comprised non-inflammatory glomerulonephritis and normal tissue. Fractalkine mRNA was predominantly expressed in the major compartment, glomerular or tubulointerstitial, affected by disease and with the strongest expression localized to vascular sites local to inflammation. In acute renal allograft rejection, there was increased expression of fractalkine mRNA by tubular epithelial cells. There was no expression of fractalkine by infiltrating leukocytes and there was only sparse expression in control tissue. Fractalkine mRNA expression correlated with infiltrating leukocyte subsets. Immunohistochemistry confirmed this pattern of expression, with serial section co-localization showing fractalkine expression in areas with macrophage (CD68+) and T cell (CD3+) infiltrates. These expression patterns show that fractalkine is a strong candidate for directing mononuclear cell infiltration in human renal inflammation.     

Contribution of putative genetic factors and candidate gene variants to inter-individual variation of circulating fractalkine (CX3CL1) levels in a large UK twins’ sample

Objective

Soluble fractalkine (sFRACT) is involved in the pathogenesis of several clinical diseases. Our major objective was to determine to what extent its variation is governed by genetic factors and whether this genetic variation could be attributable to SNPs in five candidate genes: CX3CL1, CX3CR1, ADAM10, ADAM17 and AREG.

Methods

Plasma levels of sFRACT and 38 SNPs, with minor allele frequency >0.1 were examined in a large twin sample drawn from the general UK population. The discovery sample included 3306 middle-aged females: 1172 MZ twins and 2134 DZ twins. A replication sample of 1675 twins was used to validate the major association results obtained in genetic association analysis in the discovery sample. We implemented variance component analysis to estimate contribution of putative genetic, (including above SNPs) and environmental factors to sFRACT variation.

Results

sFRACT was found not to vary with either age or BMI. Putative genetic factors (heritability) explained 43.6 ± 3% of the total variation of plasma sFRACT levels. However, we found no evidence of association between sFRACT and any of the examined SNPs, despite having >85% power to detect an association of just 1% of the variance explained. The results in the discovery and replication samples were in good agreement suggesting these findings are real.

Conclusion

Our results suggest involvement of genetic factors to inter-individual variation of sFRACT levels in a general human population. However, further studies are required to determine genetic polymorphisms affecting sFRACT variation.     

Signal transduction involved in CTGF-induced production of chemokines in mesangial cells

Objective and design. This study investigates the regulatory role of connective tissue growth factor (CTGF) on production of fractalkine, monocyte-chemoattractant protein-1 (MCP-1) and regulated on activation, normal T cell expressed and secreted (RANTES) in human mesangial cells, and explore the mechanisms of CTGF action.

Methods. Cultured human mesangial cells were treated with CTGF. Expressions of mRNA and proteins of fractalkine, MCP-1 and RANTES were analyzed by real-time polymerase chain reaction (PCR) and by enzyme-linked immunosorbent assay, respectively. Expressions of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), phosphoinositide 3-kinase (PI3-K) and protein kinase B (PKB) were assessed by Western blotting. Activities of nuclear factor-κB (NF-κB) were determined by NF-κB luciferase reporter assay.

Results. CTGF enhanced the mRNA expressions and protein release of fractalkine, MCP-1 and RANTES, and the expressions of phosphorylated ERK1/2, PI3-K and PKB, and activities of NF-κB. Blockade of ERK1/2 inhibited the CTGF-induced expression of phosphorylated ERK1/2 and NF-κB, and partially decreased the expressions of the above chemokines. PI3-K blockade downregulated the CTGF-stimulated expressions of phosphorylated PI3-K, PKB and NF-κB but not phosphorylated ERK1/2, partially decreased the expressions of the above chemokines. NF-κB blockade abrogated the CTGF-activated NF-κB and partially decreased the expressions of the above chemokines. Soluble heparin and K252a, an inhibitor of Trk, blocked CTGF-induced production of the above chemokines and the activation of the above signaling proteins.

Conclusion. These results demonstrated that CTGF induces production of fractalkine, MCP-1 and RANTES via ERK1/2 and PI3-K/PKB/NF-κB-dependent signal pathway mediated by cell surface heparin sulfate proteoglycans and the tyrosine kinase receptor TrkA in human mesangial cells.     

冠心病患者血浆Fractalkine和MMP9水平的相关性及意义

目的 观察不同类型冠心病患者血浆Fractalkine和基质金属蛋白酶9(matrix metalloproteinase9,MMP9)的水平,并探讨两者之间的相关性.方法 研究对象分为三组:(1)急性心肌梗死组(AMI组)45例,(2)稳定性冠心病组(SAP组)50例,(3)对照组 28例;采用酶联免疫吸附试验方法检测研究对象血浆Fractalkine和MMP9水平.结果 (1) 三组间血浆Fractalkine(7.422±0.868 vs 4.967±0.667 vs 3.477±0.556 P＜0.001 )和MMP9(5937.405±506.367 vs 2756.251±217.986 vs 2204.451±275.496 P＜0.001 )水平比较,差异有显著统计学意义;(2) 三组Fractalkine和MMP9血浆水平都呈正相关(P＜0.001).结论 冠心病患者Fractalkine血浆水平和MMP9血浆水平都能反映病变活动性,且两者具有较好相关性.