Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.
Grazing Animal Unit, Division of Grassland Farming, Institute of Livestock and Grassland Science, NARO, Nasushiobara, Japan.
Anim Sci J. 2022 Jan-Dec;93(1):e13750. doi: 10.1111/asj.13750.
Neonatal calves are highly susceptible to infectious disorders including diarrhea. Therefore, epithelial innate immunity, including antimicrobial peptides/proteins (AMPs), is important during the early stage of their lives. Chemerin, a multifunctional protein that was originally identified as a chemokine, possesses a potent antimicrobial activity. The present study investigated the expression levels of chemerin in the gastrointestinal (GI) tract of growing calves. Chemerin and its coding gene, retinoic acid receptor responder protein 2 (RARRES2), were highly expressed in duodenum, jejunum, and ileum compared with other parts of the GI tract. Immunohistochemistry demonstrated that chemerin-producing cells were localized in the crypt of the intestinal mucosa. Finally, the expression level of RARRES2 was higher compared with those of other major AMPs in duodenum, although it was lower compared with that of enteric β-defensin but mostly higher than those of other AMPs in jejunum and ileum at various ages in calves. The expression levels of RARRES2 were not influenced by the age of calves in duodenum and jejunum, whereas a higher expression level of RARRES2 in ileum was observed in younger calves. This study revealed that chemerin is produced in the small intestine of calves and has the potential to contribute to the gut epithelial barrier system.
新生犊牛易患感染性疾病，包括腹泻。因此，上皮固有免疫，包括抗菌肽/蛋白（AMPs），在其生命的早期阶段很重要。趋化素最初被鉴定为趋化因子，是一种多功能蛋白，具有很强的抗菌活性。本研究调查了生长中的犊牛胃肠道（GI）中趋化素的表达水平。与 GI 道的其他部位相比，趋化素及其编码基因视黄酸受体应答蛋白 2（RARRES2）在十二指肠、空肠和回肠中高度表达。免疫组织化学显示，趋化素产生细胞位于肠黏膜隐窝。最后，RARRES2 的表达水平在十二指肠中高于其他主要 AMPs，但低于肠防御素β，但在不同年龄的犊牛空肠和回肠中，大多数 AMPs 的表达水平均高于其他 AMPs。RARRES2 的表达水平在十二指肠和空肠中不受犊牛年龄的影响，而在回肠中，年轻犊牛的 RARRES2 表达水平更高。本研究表明，趋化素在犊牛的小肠中产生，并有潜力有助于肠道上皮屏障系统。
