Departament Biologia Cellular, Immunologia i Fisiologia Animal Universitat Autónoma de Barcelona, Barcelona, Spain.
Innate Immun. 2011 Feb;17(1):16-28. doi: 10.1177/1753425909348232. Epub 2010 Jan 18.
Macrophages are phagocytes that have a central role in the organization of the immune system after an infection. These cells can recognize specific molecular components of micro-organisms (pathogen-associated molecular patterns, PAMPs) via specific receptors (PRRs) and elicit specific cellular responses. In the past, the expression of immune genes in response to different PAMPs has been characterized in different fish species. However, little is known about actual cytokine release. We characterized the secretion of tumour necrosis factor (TNF)-α in primary macrophage cultures of rainbow trout (Oncorhynchus mykiss) in response to several PAMPs by Western blot and compared this to the induction of TNF-α gene expression as well as other pro-inflammatory cytokines such as interleukin (IL)-1β and IL-6 and anti-viral molecules such as INF-α and Mx protein (Mx). We show that lipopolysaccharide (LPS) and zymosan are major inducers of TNF-α secretion, which is not initially linked to the induction of TNF-α mRNA expression. The secretion of TNF-α, but intriguingly not the expression, is also stimulated by ultrapure LPS meaning that, in fish, contaminants of commercial LPS preparations are better inducers of the inflammatory response. Moreover, we have characterized the signaling pathways that are activated by different PAMPs and the link between those pathways and the final step of TNF-α secretion: TNF-α shedding by TNF-α converting enzyme (TACE/ ADAM17). For the first time, we show that, in fish macrophages, TNF-α is processed by TACE-like activity and this cleavage is dependent upon the activation of ERK, p38MAPK and JNK signaling pathways by LPS.
巨噬细胞是吞噬细胞，在感染后在免疫系统的组织中起核心作用。这些细胞可以通过特定的受体（PRRs）识别微生物的特定分子成分（病原体相关分子模式，PAMPs），并引发特定的细胞反应。过去，已经在不同的鱼类物种中描述了针对不同 PAMPs 的免疫基因的表达。然而，对于实际细胞因子的释放知之甚少。我们通过 Western blot 描述了虹鳟（Oncorhynchus mykiss）原代巨噬细胞培养物对几种 PAMPs 的肿瘤坏死因子（TNF）-α的分泌，并将其与 TNF-α基因表达的诱导以及其他促炎细胞因子（如白细胞介素（IL）-1β和 IL-6）和抗病毒分子（如 INF-α和 Mx 蛋白（Mx））进行了比较。我们表明，脂多糖（LPS）和酵母聚糖是 TNF-α分泌的主要诱导剂，而 TNF-α mRNA 表达的诱导最初与 TNF-α分泌无关。TNF-α的分泌（但有趣的是，不是表达）也被超纯 LPS 刺激，这意味着在鱼类中，商业 LPS 制剂的污染物是更好的炎症反应诱导剂。此外，我们还描述了不同 PAMPs 激活的信号通路以及这些通路与 TNF-α分泌的最后步骤之间的联系：TNF-α转换酶（TACE/ADAM17）对 TNF-α的切割。我们首次表明，在鱼类巨噬细胞中，TNF-α通过类似于 TACE 的活性进行加工，这种切割依赖于 LPS 激活 ERK、p38MAPK 和 JNK 信号通路。
