Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Japan.
Front Immunol. 2023 Sep 12;14:1259519. doi: 10.3389/fimmu.2023.1259519. eCollection 2023.
The interactions between the host immune system and intestinal microorganisms have been studied in many animals, including fish. However, a detailed analysis has not been performed in medaka, an established fish model for biological studies. Here, we investigated the effect of immunodeficiency on the microbiota composition and the effect of gut bacteria on intestinal epithelial development and immune responses in medaka. Chronological analysis of the intestinal microbiota of mutant medaka showed a gradual decrease in the evenness of operational taxonomic units, mainly caused by the increased abundance of the Aeromonadaceae family. Exposure of wild-type medaka to high doses of an intestine-derived opportunistic bacterium of the Aeromonadaceae family induced an inflammatory response, suggesting a harmful effect on adult mutants. In addition, we established germ-free conditions in larval medaka and observed large absorptive vacuoles in intestinal epithelial cells, indicating a block in epithelial maturation. Transcriptome analysis revealed a decrease in the expression of genes involved in the defense response, including the antimicrobial peptide gene , whose expression is induced by lipopolysaccharide stimulation in normal larvae. These results show that reciprocal interactions between the microbiome and the intestinal tract are required for the maturation of the medaka immune system.
宿主免疫系统与肠道微生物之间的相互作用已在许多动物中进行了研究，包括鱼类。然而，在斑马鱼中尚未进行详细分析，斑马鱼是生物学研究中一种成熟的鱼类模型。在这里，我们研究了免疫缺陷对微生物群落组成的影响，以及肠道细菌对斑马鱼肠道上皮发育和免疫反应的影响。对 突变体斑马鱼肠道微生物的时间序列分析表明，操作分类单元的均匀度逐渐降低，主要是由于 Aeromonadaceae 家族的丰度增加所致。将野生型斑马鱼暴露于高剂量的 Aeromonadaceae 家族的肠道衍生机会致病菌中会引起炎症反应，表明对成年 突变体有害。此外，我们在幼体斑马鱼中建立了无菌条件，并观察到肠道上皮细胞中存在大量吸收性空泡，表明上皮成熟受阻。转录组分析显示，参与防御反应的基因表达减少，包括抗菌肽基因 ，其在正常幼虫中受脂多糖刺激诱导表达。这些结果表明，微生物组和肠道之间的相互作用是斑马鱼免疫系统成熟所必需的。
