Molecular Characterization of E-Type Prostanoid Receptor 4 (EP4) from Ayu (Plecoglossus altivelis) and Its Functional Analysis in the Monocytes/Macrophages.
Molecular Characterization of E-Type Prostanoid Receptor 4 (EP4) from Ayu (Plecoglossus altivelis) and Its Functional Analysis in the Monocytes/Macrophages.
复制标题
香鱼 E 型前列腺素受体 4 (EP4) 的分子特征及其在单核细胞/巨噬细胞中的功能分析
DOI：
10.1371/journal.pone.0147884
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Chen J
中科院分区：
文献类型：
--
作者：
Rong YJ;Lu XJ;Chen J
前列腺素E2(PGE2)通过与E型前列腺素受体(EPs)相互作用，在广泛的生理和病理过程中发挥重要作用。EP4是已知的在哺乳动物单核/巨噬细胞中介导免疫反应的四种EP亚型之一。然而，EP4在鱼类中的确切功能和特征仍不清楚。在这项研究中，我们鉴定了一个新的类EP4(PaEP4L)基因。PaEP4L基因全长2781个核苷酸，编码459个氨基酸残基的多肽，计算相对分子质量为51.17 kDa。序列比较和系统进化树分析表明，PaEP4L与大西洋鲑鱼(Salmo Salar)的氨基酸同源性为76%。用实时荧光定量聚合酶链式反应检测所有受试组织和头肾单核/巨噬细胞(MO/MФ)中PaEP4L基因的表达。鳗弧菌感染后，肝、脾和MO/MФ均有较大变化。Western印迹分析表明，感染鳗弧菌后，AYU MO/MФ细胞匀浆中PAEP4L的表达显著增加。此外，抗PaEP4LIg G可逆转前列腺素E_2诱导的AYU MO/M细胞中白细胞介素1β(IL-1β)和肿瘤坏死因子α(TN-α)的表达下调及吞噬功能。PGE2处理细胞和未处理细胞的呼吸爆发反应无显著差异。我们进一步发现，在AYU MO/MФ中，cAMP介导了PGE_2/PAEP4L信号通路。综上所述，我们的结果表明，PaEP4L介导了前列腺素E_2对AYU MO/MФ功能的影响，揭示了EP4对鱼类先天免疫系统细胞的调节作用。
Prostaglandin E2 (PGE2) plays an important role in a broad spectrum of physiological and pathological processes by interacting with E-type prostanoid receptors (EPs). EP4 is one of four EP subtypes known to mediate the immune response in mammalian monocytes/macrophages. However, the precise function and characteristics of EP4 in fish remain unclear. In this study, we characterized a novel EP4-like (PaEP4L) gene from ayu, Plecoglossus altivelis. The cDNA sequence of PaEP4L is 2781 nucleotides (nts) in length, encoding a polypeptide of 459 amino acid residues with a calculated molecular weight of 51.17 kDa. Sequence comparison and phylogenetic tree analysis showed that PaEP4L shared 76% amino acid identity with that of the Atlantic salmon (Salmo salar). PaEP4L mRNA was detected by real-time quantitative PCR (QPCR) in all tested tissues and head kidney-derived monocytes/macrophages (MO/MФ). It varied greatly in liver, spleen and MO/MФ upon Vibrio anguillarum infection. Western blot analysis revealed a significant increase of PaEP4L in cell homogenates from ayu MO/MФ upon V. anguillarum infection. Moreover, anti-PaEP4L IgG reversed the down-regulation of interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) mRNA expression as well as phagocytosis in ayu MO/MФ caused by PGE2. There were no significant differences in the respiratory burst response between PGE2 treated and untreated cells. We further found that cAMP mediated PGE2/PaEP4L signal in ayu MO/MФ. In conclusion, our results indicate that PaEP4L mediates PGE2 effects on ayu MO/MФ function, revealing that EP4 also plays a role in the modulation of cells of the fish’s innate immune system.