Cheng Yujiao, Ren Yan, Zhang Wangdong, Lu Jia, Xie Fei, Fang Ying-Dong, Fan Xiping, He Wanhong, Wang Wenhui
College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, Gansu, China.
Davies Livestock Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA, Australia.
Front Immunol. 2024 Nov 26;15:1464664. doi: 10.3389/fimmu.2024.1464664. eCollection 2024.
Peyer's patches (PPs) are crucial antigen-inductive sites of intestinal mucosal immunity. Prior research indicated that, in contrast to other ruminants, PPs in the small intestine of Bactrian camels are found in the duodenum, jejunum, and ileum and display polymorphism. Using this information, we analyzed the microbial and metabolic characteristics in various segments of the Bactrian camel's small intestine to further elucidate how the immune system varies across different regions.
In this study, the microbiota and metabolite of 36 intestinal mucosal samples, including duodenal (D-PPs), jejunal (J-PPs), and ileal PPs (I-PPs), were profiled for six Bactrian camels using 16S rRNA gene sequencing and liquid chromatography with tandem mass spectrometry (LC-MS/MS). To confirm meaningful associations, we conducted connection analyses on the significantly different objects identified in each group's results. ELISA was used to analyze the levels of IgA, IgG, and IgM in the same tissues.
The microbiota and metabolite profiles of J-PPs and I-PPs were found to be similar, whereas those of D-PPs were more distinct. In J-PPs and I-PPs, the dominant bacterial genera included , , and . In contrast, D-PPs had a significant increase in the abundance of , , and . Regarding the metabolomics, D-PPs exhibited high levels of polypeptides, acetylcholine, and histamine. On the other hand, J-PPs and I-PPs were characterized by an enrichment of free amino acids, such as L-arginine, L-glutamic acid, and L-serine. These metabolic differences mainly involve amino acid production and metabolic processes. Furthermore, the distribution of intestinal immunoglobulins highlighted the specificity of D-PPs. Our results indicated that proinflammatory microbes and metabolites were significantly enriched in D-PPs. In contrast, J-PPs and I-PPs contained substances that more effectively enhance immune responses, as evidenced by the differential distribution of IgA, IgG, and IgM.
The intestinal microenvironment of Bactrian camels displays distinct regional disparities, which we propose are associated with variations in immunological function throughout different segments of the small intestine. This study highlights the specific traits of the intestinal microbiota and metabolites in Bactrian camels, offering a valuable reference for understanding the relationship between regional intestinal immunity and the general health and disease of the host.
派尔集合淋巴结（PPs）是肠道黏膜免疫的关键抗原诱导部位。先前的研究表明，与其他反刍动物不同，双峰驼小肠中的PPs存在于十二指肠、空肠和回肠中，且表现出多态性。利用这些信息，我们分析了双峰驼小肠不同节段的微生物和代谢特征，以进一步阐明免疫系统在不同区域的差异。
在本研究中，使用16S rRNA基因测序和液相色谱-串联质谱法（LC-MS/MS）对6峰双峰驼的36份肠道黏膜样本（包括十二指肠PPs（D-PPs）、空肠PPs（J-PPs）和回肠PPs（I-PPs））的微生物群和代谢物进行了分析。为了确认有意义的关联，我们对每组结果中鉴定出的显著差异对象进行了关联分析。使用酶联免疫吸附测定（ELISA）分析相同组织中IgA、IgG和IgM的水平。
发现J-PPs和I-PPs的微生物群和代谢物谱相似，而D-PPs的则更为独特。在J-PPs和I-PPs中，优势细菌属包括 、 和 。相比之下，D-PPs中 、 和 的丰度显著增加。在代谢组学方面，D-PPs表现出高水平的多肽、乙酰胆碱和组胺。另一方面，J-PPs和I-PPs的特征是富含游离氨基酸，如L-精氨酸、L-谷氨酸和L-丝氨酸。这些代谢差异主要涉及氨基酸的产生和代谢过程。此外，肠道免疫球蛋白的分布突出了D-PPs的特异性。我们的结果表明，促炎微生物和代谢物在D-PPs中显著富集。相比之下，J-PPs和I-PPs含有更有效地增强免疫反应的物质，IgA、IgG和IgM的差异分布证明了这一点。
双峰驼的肠道微环境表现出明显的区域差异，我们认为这与小肠不同节段免疫功能的变化有关。本研究突出了双峰驼肠道微生物群和代谢物的特定特征，为理解区域肠道免疫与宿主整体健康和疾病之间的关系提供了有价值的参考。
