Bacterial Lipopolysaccharide Induced Alterations of Genome-Wide DNA Methylation and Promoter Methylation of Lactation-Related Genes in Bovine Mammary Epithelial Cells
Jingbo Chen 1,†, Yongjiang Wu 1,†, Yawang Sun 1, Xianwen Dong 2, Zili Wang 1, Zhu Zhang 1, Yanli Xiao 3 and Guozhong Dong 1,*
1
College of Animal Science and Technology, Southwest University, Beibei 400716, China
2
Institute for Herbivorous Livestock Research, Chongqing Academy of Animal Science, Chongqing 402460, China
3
College of International Studies, Southwest University, Beibei 400716, China
*
Author to whom correspondence should be addressed.
†
These two authors contribute equally to this work.
Toxins 2019, 11(5), 298; https://doi.org/10.3390/toxins11050298
Received: 30 March 2019 / Revised: 16 May 2019 / Accepted: 24 May 2019 / Published: 24 May 2019
(This article belongs to the Special Issue Lipopolysaccharide: Bacterial Endotoxin)
Abstract
Bacterial lipopolysaccharide (LPS) could result in poor lactation performance in dairy cows. High methylation of DNA is associated with gene repression. However, it is unclear whether LPS could suppress the expression of lactation-related genes by inducing DNA methylation. Therefore, the objective of this study was to investigate the impact of LPS on genome-wide DNA methylation, using methylated DNA immunoprecipitation with high-throughput sequencing (MeDIP-seq) and on the promoter methylation of lactation-related genes using MassArray analysis in bovine mammary epithelial cells. The bovine mammary epithelial cell line MAC-T cells were treated for 48 h with LPS at different doses of 0, 1, 10, 100, and 1000 endotoxin units (EU)/mL (1 EU = 0.1 ng). The results showed that the genomic methylation levels and the number of methylated genes in the genome as well as the promoter methylation levels of milk genes increased when the LPS dose was raised from 0 to 10 EU/mL, but decreased after further increasing the LPS dose. The milk gene mRNA expression levels of the 10 EU/mL LPS treatment were significantly lower than these of untreated cells. The results also showed that the number of hypermethylated genes was greater than that of hypomethylated genes in lipid and amino acid metabolic pathways following 1 and 10 EU/mL LPS treatments as compared with control. By contrast, in the immune response pathway the number of hypomethylated genes increased with increasing LPS doses. The results indicate LPS at lower doses induced hypermethylation of the genome and promoters of lactation-related genes, affecting milk gene mRNA expression. However, LPS at higher doses induced hypomethylation of genes involved in the immune response pathway probably in favor of immune responses. View Full-TextKeywords:
lipopolysaccharide; endotoxin; DNA methylation; bovine; mammary; epithelial cells
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Chen, J.; Wu, Y.; Sun, Y.; Dong, X.; Wang, Z.; Zhang, Z.; Xiao, Y.; Dong, G. Bacterial Lipopolysaccharide Induced Alterations of Genome-Wide DNA Methylation and Promoter Methylation of Lactation-Related Genes in Bovine Mammary Epithelial Cells. Toxins 2019, 11, 298.
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