Transcriptional Study Revealed That Boron Supplementation May Alter the Immune-Related Genes Through MAPK Signaling in Ostrich Chick Thymus.

The objective of this study is to construct a digital gene expression tag profile to identify genes potentially related to immune response in the ostrich. Exposure to boron leads to an immune response in the ostrich, although the underlying mechanism remains obscure. Thus, a dire need of biological resource in the form of transcriptomic data for ostriches arises to key out genes and to gain insights into the function of boron on the immune response of thymus. For this purpose, RNA-Seq analysis was performed using the Illumina technique to investigate differentially expressed genes in ostrich thymuses treated with different boric acid concentrations (0, 80, and 640 mg/L). Compared with the control group, we identified 309 upregulated and 593 downregulated genes in the 80 mg/L treated sample and 228 upregulated and 1816 downregulated genes in 640 mg/L treated sample, respectively. Trend analysis of these differentially expressed genes uncovers three statistically significant trends. Functional annotation analysis of the differentially expressed genes verifies multiple functions associated with immune response. When ostrich thymuses were treated with boron, expression changes were observed in genes predominantly associated with MAPK and calcium signaling pathways. The results of this study provide all-inclusive information on gene expression at the transcriptional level that further enhances our apprehension for the molecular mechanisms of boron on the ostrich immune system. The calcium and MAPK signaling pathways might play a pivotal role in regulating the immune response of boron-treated ostriches.