Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706, USA.
Int Immunol. 2011 Dec;23(12):713-28. doi: 10.1093/intimm/dxr083. Epub 2011 Oct 24.
This study tested the hypothesis that human eosinophils produce ligands for the receptor for advanced glycation end-products (RAGE), express RAGE and exhibit RAGE-mediated responses. In examining our microarray data, we identified the presence of RAGE and RAGE ligand (S100A4, S100A6, S100A8, S100A9, S100A11, S100P, HMGB1) transcripts. Expression of eosinophil RAGE mRNA was also compared with a known positive control and further assessed via bioinformatics and sequence analysis of RAGE cDNA. Positive and negative controls were used to identify RAGE, S100A8 and S100A9 protein in human primary eosinophils. Immunoblot assessment of eosinophils treated with cytokines (IL-5 or granulocyte macrophage colony-stimulating factor) indicated an up-regulation of S100A8 and S100A9 production, whereas co-treatment of eosinophils with a RAGE ligand and cytokines displayed a down-regulation in the levels of RAGE. Analysis of eosinophil-conditioned media revealed that eosinophils are capable of releasing RAGE, S100A8 and S100A9. To test the eosinophil response to RAGE activation, the most well-characterized RAGE ligand, S100B, was examined. Treatment of eosinophils with S100B resulted in RAGE-mediated PKC-delta phosphorylation, a 3-fold dose-dependent increase in cell survival and an increase in the level of cellular RAGE. Combined, these studies reveal eosinophil expression of RAGE, RAGE ligands and RAGE-mediated responses. The expression of eosinophil RAGE, soluble RAGE and RAGE ligands may be pivotal to the functions of eosinophils in various human diseases involving RAGE and S100 ligands.
这项研究检验了这样一个假设,即人类嗜酸性粒细胞产生晚期糖基化终产物(RAGE)受体的配体,表达 RAGE 并表现出 RAGE 介导的反应。在检查我们的微阵列数据时,我们发现了 RAGE 和 RAGE 配体(S100A4、S100A6、S100A8、S100A9、S100A11、S100P、HMGB1)转录本的存在。还比较了嗜酸性粒细胞 RAGE mRNA 的表达,并用生物信息学和 RAGE cDNA 序列分析进一步评估。使用阳性和阴性对照来鉴定人原代嗜酸性粒细胞中的 RAGE、S100A8 和 S100A9 蛋白。用细胞因子(IL-5 或粒细胞巨噬细胞集落刺激因子)处理嗜酸性粒细胞的免疫印迹评估表明 S100A8 和 S100A9 的产生上调,而嗜酸性粒细胞与 RAGE 配体和细胞因子共同处理则显示 RAGE 水平下调。对嗜酸性粒细胞条件培养基的分析表明,嗜酸性粒细胞能够释放 RAGE、S100A8 和 S100A9。为了测试 RAGE 激活对嗜酸性粒细胞的反应,研究了最具特征性的 RAGE 配体 S100B。用 S100B 处理嗜酸性粒细胞导致 RAGE 介导的 PKC-delta 磷酸化、细胞存活增加 3 倍的剂量依赖性以及细胞内 RAGE 水平增加。综上所述,这些研究揭示了嗜酸性粒细胞表达 RAGE、RAGE 配体和 RAGE 介导的反应。嗜酸性粒细胞 RAGE、可溶性 RAGE 和 RAGE 配体的表达可能对涉及 RAGE 和 S100 配体的各种人类疾病中嗜酸性粒细胞的功能至关重要。