INRAE, AgroParisTech, GABI, Université Paris-Saclay, Jouy-en-Josas, France.
UVSQ, INRAE, BREED, Université Paris-Saclay, Jouy-en-Josas, France.
Epigenetics. 2023 Dec;18(1):2215620. doi: 10.1080/15592294.2023.2215620.
Mastitis is among the main reasons women cease breastfeeding. In farm animals, mastitis results in significant economic losses and the premature culling of some animals. Nevertheless, the effect of inflammation on the mammary gland is not completely understood. This article discusses the changes to DNA methylation in mouse mammary tissue caused by lipopolysaccharide-induced inflammation after in vivo intramammary challenges and the differences in DNA methylation between 1 and 2 lactations. Lactation rank induces 981 differential methylations of cytosines (DMCs) in mammary tissue. Inflammation in 1 lactation compared to inflammation in 2 lactation results in the identification of 964 DMCs. When comparing inflammation in 1 . 2 lactations with previous inflammation history, 2590 DMCs were identified. Moreover, Fluidigm PCR data show changes in the expression of several genes related to mammary function, epigenetic regulation, and the immune response. We show that the epigenetic regulation of two successive physiological lactations is not the same in terms of DNA methylation and that the effect of lactation rank on DNA methylation is stronger than that of the onset of inflammation. The conditions presented here show that few DMCs are shared between comparisons, suggesting a specific epigenetic response depending on lactation rank, the presence of inflammation, and even whether the cells had previously suffered inflammation. In the long term, this information could lead to a better understanding of the epigenetic regulation of lactation in both physiological and pathological conditions. RRBS, reduced representation bisulphite sequencing; RT-qPCR, real-time quantitative polymerase chain reaction; MEC, mammary epithelial cells; MaSC, mammary stem cell; 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.
乳腺炎是导致女性停止母乳喂养的主要原因之一。在农场动物中，乳腺炎会导致重大的经济损失，并导致一些动物提前被淘汰。然而，炎症对乳腺的影响尚未被完全理解。本文讨论了体内乳腺内挑战后脂多糖诱导的炎症引起的小鼠乳腺组织中 DNA 甲基化的变化，以及 1 次和 2 次泌乳之间 DNA 甲基化的差异。泌乳等级导致乳腺组织中 981 个胞嘧啶（DMC）的差异甲基化。与 2 次泌乳时的炎症相比，1 次泌乳时的炎症导致鉴定出 964 个 DMC。当将 1 次和 2 次泌乳时的炎症与之前的炎症史进行比较时，鉴定出 2590 个 DMC。此外，Fluidigm PCR 数据显示与乳腺功能、表观遗传调控和免疫反应相关的几个基因的表达发生变化。我们表明，在 DNA 甲基化方面，两个连续的生理泌乳的表观遗传调控是不同的，泌乳等级对 DNA 甲基化的影响强于炎症的发生。这里呈现的条件表明，在比较之间很少有 DMC 是共享的，这表明根据泌乳等级、炎症的存在，甚至细胞是否以前遭受过炎症，存在特定的表观遗传反应。从长远来看，这些信息可以使人们更好地理解生理和病理条件下泌乳的表观遗传调控。RRBS，简化代表性亚硫酸氢盐测序；RT-qPCR，实时定量聚合酶链反应；MEC，乳腺上皮细胞；MaSC，乳腺干细胞；TSS，转录起始位点；TTS，转录终止位点；UTR，非翻译区；SINE，短散在核元件；LINE，长散在核元件；CGI，CpG 岛；DEG，差异表达基因；DMC，差异甲基化胞嘧啶；DMR，差异甲基化区；GO 术语，基因本体术语；MF，分子功能；BP，生物学过程。
