Li Yang, Song Wei-Jia, Yi Shao-Kui, Yu Hui-Xia, Mo Hao-Lin, Yao Ming-Xing, Tao Ya-Xiong, Wang Li-Xin
College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
College of Life Sciences, Huzhou University, Huzhou 313000, China.
Animals (Basel). 2023 Sep 23;13(19):3001. doi: 10.3390/ani13193001.
The G-protein-coupled receptor GPR84, activated by medium-chain fatty acids, primarily expressed in macrophages and microglia, is involved in inflammatory responses and retinal development in mammals and amphibians. However, our understanding of its structure, function, tissue expression, and signaling pathways in fish is limited. In this study, we cloned and characterized the coding sequence of GPR84 (ciGPR84) in grass carp. A phylogenetic analysis revealed its close relationship with bony fishes. High expression levels of GPR84 were observed in the liver and spleen. The transfection of HEK293T cells with ciGPR84 demonstrated its responsiveness to medium-chain fatty acids and diindolylmethane (DIM). Capric acid, undecanoic acid, and lauric acid activated ERK and inhibited cAMP signaling. Lauric acid showed the highest efficiency in activating the ERK pathway, while capric acid was the most effective in inhibiting cAMP signaling. Notably, DIM did not activate GPR84 in grass carp, unlike in mammals. These findings provide valuable insights for mitigating chronic inflammation in grass carp farming and warrant further exploration of the role of medium-chain fatty acids in inflammation regulation in this species.
G蛋白偶联受体GPR84由中链脂肪酸激活，主要在巨噬细胞和小胶质细胞中表达，参与哺乳动物和两栖动物的炎症反应及视网膜发育。然而，我们对其在鱼类中的结构、功能、组织表达及信号通路的了解有限。在本研究中，我们克隆并鉴定了草鱼中GPR84（ciGPR84）的编码序列。系统发育分析显示它与硬骨鱼类关系密切。在肝脏和脾脏中观察到GPR84的高表达水平。用ciGPR84转染HEK293T细胞证明其对中链脂肪酸和二吲哚甲烷（DIM）有反应。癸酸、十一烷酸和月桂酸激活ERK并抑制cAMP信号。月桂酸在激活ERK途径方面效率最高，而癸酸在抑制cAMP信号方面最有效。值得注意的是，与哺乳动物不同，DIM在草鱼中不激活GPR84。这些发现为减轻草鱼养殖中的慢性炎症提供了有价值的见解，并值得进一步探索中链脂肪酸在该物种炎症调节中的作用。
