Institute of Reproductive Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
Institute of Genome Biology, FBN, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
Cells. 2020 Mar 31;9(4):836. doi: 10.3390/cells9040836.
The cellular glycocalyx of vertebrates is frequently decorated with sialic acid residues. These sialylated structures are recognized by sialic acid-binding immunoglobulin-type lectins (Siglecs) of immune cells, which modulate their responsiveness. Fifteen Siglecs are known to be expressed in humans, but only four Siglecs are regularly present in fish: Siglec1, CD22, myelin-associated glycoprotein (MAG), and Siglec15. While several studies have dealt with the physiological roles of these four Siglecs in mammals, little is known about Siglecs in fish. In the present manuscript, the expression landscapes of these Siglecs were determined in the two salmonid species and and in the percid fish This gene-expression profiling revealed that the expression of is not restricted to neuronal cells but is detectable in all analyzed blood cells, including erythrocytes. The teleostean MAG contains the inhibitory motif ITIM; therefore, an additional immunomodulatory function of MAG is likely to be present in fish. Besides , , , and were also expressed in all analyzed blood cell populations. Interestingly, the expression profiles of genes encoding Siglecs and particular associated enzymes changed in a gene- and tissue-specific manner when was exposed to handling stress. Thus, the obtained data indicate once more that stress directly affects immune-associated processes.
脊椎动物的细胞糖萼经常被唾液酸残基修饰。这些唾液酸化的结构被免疫细胞的唾液酸结合免疫球蛋白型凝集素（Siglec）识别，从而调节其反应性。已知人类有 15 种 Siglec 表达，但鱼类中只有 4 种 Siglec 经常存在：Siglec1、CD22、髓鞘相关糖蛋白（MAG）和 Siglec15。虽然有几项研究涉及这四种 Siglec 在哺乳动物中的生理作用，但对鱼类 Siglec 的了解甚少。在本手稿中，确定了这四种 Siglec 在两种鲑鱼 和 和鲈形目鱼类 中的表达图谱。这种基因表达谱分析表明， 的表达不仅局限于神经元细胞，而且在所有分析的血细胞中都可检测到，包括红细胞。硬骨鱼的 MAG 含有抑制基序 ITIM；因此，MAG 在鱼类中可能具有额外的免疫调节功能。除了 之外， 、 、 和 也在所有分析的血细胞群体中表达。有趣的是，当 暴露于处理应激时，编码 Siglec 和特定相关酶的基因的表达谱以基因和组织特异性的方式发生变化。因此，获得的数据再次表明，应激直接影响免疫相关过程。
