巨噬细胞在实验性自身免疫性脑脊髓炎中表达 HGF 受体 c-met。
Expression of the HGF receptor c-met by macrophages in experimental autoimmune encephalomyelitis.
机构信息
Division of Clinical Immunology, University Hospital Zurich, Moussonstrasse 13, CH-8044 Zürich, Switzerland.
出版信息
Glia. 2010 Apr;58(5):559-71. doi: 10.1002/glia.20945.
Hepatocyte growth factor (HGF) is a pleiotropic cytokine able to evoke a wide array of cellular responses including proliferation, migration, and survival through activation of its receptor c-met. Various types of leukocytes have been described to express c-met suggesting that HGF/c-met signaling may directly influence leukocyte responses in inflammation. We have investigated the HGF/c-met pathway in experimental autoimmune encephalomyelitis (EAE), a common mouse model of multiple sclerosis (MS), in which macrophages play a dual role, contributing directly to CNS damage at disease onset but promoting recovery during remission by removing myelin debris. Here we show that during EAE both HGF and c-met are expressed in the CNS and that c-met is activated. We subsequently demonstrate that c-met is primarily expressed in inflammatory lesions by macrophages and a small number of dendritic cells (DCs) and oligodendrocyte progenitor cells (OPCs) but not by microglia or T cells. Complementary in vitro experiments show that only LPS and TNFalpha, but not IL-6, IL-10, or IL-13, are able to induce c-met expression in macrophages. In addition, using TNF signaling deficient macrophages we demonstrate that LPS and TNFalpha induce c-met through distinct pathways. Furthermore, TNFalpha- and LPS-induced c-met is functional because treatment of macrophages with recombinant HGF results in rapid phosphorylation of c-met. Interestingly, HGF/c-met signaling does not modulate cytokine expression, phagocytosis, or antigen presentation but promotes proliferation of activated macrophages. Taken together, our data indicate a pro-inflammatory role for the HGF/c-met pathway in EAE rather than a role in the initiation of repair mechanisms.
肝细胞生长因子 (HGF) 是一种多功能细胞因子,能够通过激活其受体 c-met 引发广泛的细胞反应,包括增殖、迁移和存活。已经描述了各种类型的白细胞表达 c-met,表明 HGF/c-met 信号可能直接影响炎症中的白细胞反应。我们研究了实验性自身免疫性脑脊髓炎 (EAE) 中 HGF/c-met 通路,EAE 是多发性硬化症 (MS) 的常见小鼠模型,其中巨噬细胞发挥双重作用,在疾病发作时直接导致中枢神经系统损伤,但在缓解期通过清除髓磷脂碎片促进恢复。在这里,我们显示在 EAE 中,HGF 和 c-met 均在中枢神经系统中表达并且 c-met 被激活。随后,我们证明 c-met 主要由巨噬细胞和少量树突状细胞 (DC) 和少突胶质前体细胞 (OPC) 在炎症病变中表达,但不在小胶质细胞或 T 细胞中表达。补充的体外实验表明,只有 LPS 和 TNFalpha,而不是 IL-6、IL-10 或 IL-13,能够诱导巨噬细胞中 c-met 的表达。此外,使用 TNF 信号缺陷型巨噬细胞,我们证明 LPS 和 TNFalpha 通过不同的途径诱导 c-met。此外,由于用重组 HGF 处理巨噬细胞可导致 c-met 的快速磷酸化,因此 TNFalpha 和 LPS 诱导的 c-met 是功能性的。有趣的是,HGF/c-met 信号不调节细胞因子表达、吞噬作用或抗原呈递,但促进激活的巨噬细胞增殖。总之,我们的数据表明 HGF/c-met 通路在 EAE 中具有促炎作用,而不是在启动修复机制中的作用。