Complement expression in retinal pigment epithelial cells is modulated by activated macrophages
Complement expression in retinal pigment epithelial cells is modulated by activated macrophages
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DOI：
10.1016/j.exer.2013.04.016
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发表时间：
2013-07-01
影响因子：
3.4
通讯作者：
Xu, Heping
中科院分区：
文献类型：
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作者：
Luo, Chang;Zhao, Jiawu;Xu, Heping
补体激活参与多种视网膜疾病。我们以前已经表明，许多补体成分和调节剂可以在眼睛中局部产生，并且视网膜色素上皮（RPE）细胞是视网膜脉络膜界面处补体表达的主要来源。RPE细胞补体成分的表达受炎性细胞因子调节。在老化或炎症条件下，小胶质细胞和巨噬细胞在视网膜下腔中积累，在那里它们与RPE细胞密切接触。在这项研究中，我们研究了活化的巨噬细胞对RPE细胞补体表达的影响。用未活化的骨髓源性巨噬细胞（BM-DM）、经典活化的BM-DM（M1）和不同类型的交替活化的BM-DM（M2 a被IL-4活化、M2 b被免疫复合物和脂多糖（LPS）活化、M2 c被IL-10活化）的上清液处理小鼠RPE细胞。实时荧光定量RT-PCR检测RPE细胞炎性细胞因子和补体基因的表达。Western blot检测CFB、C3、C1 INH和C1 r蛋白表达。我们的研究结果表明，未受刺激的RPE细胞表达多种补体相关基因，补体调节因子，包括C1 r，H因子（CFH），DAF 1，CD 59，ClINH，Crry和C4 BP基因的表达水平显着高于补体成分基因（C2，C4，CFB，C3和C5）。巨噬细胞上清液增加RPE细胞中炎性细胞因子（IL-1 β、IL-6、iNOS）、趋化因子（CCL 2）和补体的表达。MO、M2 a和M2 c巨噬细胞的上清液轻度上调RPE细胞中CFB、CFH和C3基因的表达（2-3.5倍），而M1和M2 b巨噬细胞的上清液大幅增加RPE细胞中CFB和C3基因的表达（10-30倍）。M1和M2 b巨噬细胞培养上清也能增加RPE细胞中C1 r、C2、C4、CFH、Masp 1、ClINH和C4 BP等基因的表达，但其增加水平明显低于CFB和C3基因。M1和M2 b巨噬细胞上清液增强RPE细胞CFB（Bb片段）蛋白表达和C3分泌。M1巨噬细胞可能通过STAT 1途径影响RPE细胞中补体的表达。我们的研究结果表明，在炎症条件下，活化的巨噬细胞可以通过诱导RPE细胞CFB和C3表达来促进视网膜中补体激活的替代途径。(C)2013爱思唯尔有限公司保留所有权利。
Complement activation is involved in a variety of retinal diseases. We have shown previously that a number of complement components and regulators can be produced locally in the eye, and that retinal pigment epithelial (RPE) cells are the major source of complement expression at the retina choroidal interface. The expression of complement components by RPE cells is regulated by inflammatory cytokines. Under aging or inflammatory conditions, microglia and macrophages accumulate in the subretinal space, where they are in close contact with RPE cells. In this study, we investigated the effect of activated macrophages on complement expression by RPE cells. Mouse RPE cells were treated with the supernatants from un-activated bone marrow-derived macrophages (BM-DMs), the classically activated BM-DMs (M1) and different types of the alternatively activated BM-DMs (M2a by IL-4, M2b by immune complex and lipopolysaccharide (LPS), M2c by IL-10). The expression of inflammatory cytokines and complement genes by RPE cells were determined by real-time RT-PCR. The protein expression of CFB, C3, C1INH, and C1r was examined by Western blot. Our results show that un-stimulated RPE cells express a variety of complement-related genes, and that the expression levels of complement regulators, including C1r, factor H (CFH), DAF1, CD59, ClINH, Crry, and C4BP genes are significantly higher than those of complement component genes (C2, C4, CFB, C3, and C5). Macrophage supernatants increased inflammatory cytokine (IL-1 beta, IL-6, iNOS), chemokine (CCL2) and complement expression in RPE cells. The supernatants from MO, M2a and M2c macrophages mildly up-regulated (2-3.5-fold) CFB, CFH and C3 gene expression in RPE cells, whereas the supernatants from M1 and M2b macrophages massively increased (10-30-fold) CFB and C3 gene expression in RPE cells. The expression of other genes, including C1r, C2, C4, CFH, Masp1, ClINH, and C4BP in RPE cells was also increased by the supernatants of M1 and M2b macrophages; however, the increment levels were significantly lower than CFB and C3 genes. M1 and M2b macrophage supernatants enhanced CFB (Bb fragment) protein expression and C3 secretion by RPE cells. M1 macrophages may affect complement expression in RPE cells through the STAT1 pathway. Our results suggest that under inflammatory conditions, activated macrophages could promote the alternative pathway of complement activation in the retina via induction of RPE cell CFB and C3 expression. (C) 2013 Elsevier Ltd. All rights reserved.