DNA methylation and gene expression changes in mouse mammary tissue during successive lactations: part I – the impact of inflammation
Abstract
Mastitis is among the main reasons women cease breastfeeding, which leads to them supplementing breast milk with artificial formula. In farm animals, mastitis results in significant economic losses and the premature culling of some animals. Nevertheless, researchers do not know enough about the effect of inflammation on the mammary gland. This article discusses the changes to DNA methylation in mouse mammary tissue caused by lipopolysaccharide-induced inflammation (4 h post-injection of lipopolysaccharide). We analysed the expression of some genes related to mammary gland function, epigenetic regulation, and the immune response. The analysis focused on three comparisons: inflammation during the first lactation, inflammation during second lactation with no history of inflammation, and inflammation during second lactation with previous inflammation. We identified differentially methylated cytosines (DMCs), differentially methylated regions (DMRs), and some differentially expressed genes (DEGs) for each comparison. The three comparisons shared some DEGs; however, few DMCs and only one DMR were shared. These observations suggest that inflammation is one of several factors affecting epigenetic regulation during successive lactations. Furthermore, the comparison between animals in second lactation with and without inflammation, with no inflammation history during first lactation showed a different pattern compared to the other conditions in this experiment. This indicates that inflammation history plays an important role in determining epigenetic changes. The data presented in this study suggest that lactation rank and previous inflammation history are equally important when explaining mammary tissue gene expression and DNA methylation changes.
Keywords
DMR
differentially methylated region
GO term
gene ontology term
MF
molecular function
BP
biological process inflammation
lactation
mammary tissue
DNA methylation
RRBS
reduced representation bisulfite sequencing RT-qPCR
real-time quantitative polymerase chain reaction MEC
mammary epithelial cells TSS
transcription start site TTS
transcription termination site UTR
untranslated region SINE
short interspersed nuclear element LINE
long interspersed nuclear element CGI
CpG island DEG
differentially expressed gene DMC
differentially methylated cytosine DMR
differentially methylated region GO term
gene ontology term MF
molecular function BP
biological process inflammation lactation mammary tissue DNA methylation
reduced representation bisulfite sequencing
RT-qPCR
real-time quantitative polymerase chain reaction
MEC
mammary epithelial cells
TSS
transcription start site
TTS
transcription termination site
UTR
untranslated region
SINE
short interspersed nuclear element
LINE
long interspersed nuclear element
CGI
CpG island
DEG
differentially expressed gene
DMC
differentially methylated cytosine
Domains
Life Sciences [q-bio]| Origin | Files produced by the author(s) |
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