The Impact of Intramammary Escherichia coli Challenge on Liver and Mammary Transcriptome and Cross-Talk in Dairy Cows during Early Lactation Using RNAseq

Abstract

Our objective was to identify the biological response and the cross-talk between liver and mammary tissue after intramammary infection (IMI) with Escherichia coli (E. coli) using RNAseq technology. Sixteen cows were inoculated with live E. coli into one mammary quarter at ~4–6 weeks in lactation. For all cows, biopsies were performed at -144, 12 and 24 h relative to IMI in liver and at 24 h post-IMI in infected and non-infected (control) mammary quarters. For a subset of cows (n = 6), RNA was extracted from both liver and mammary tissue and sequenced using a 100 bp paired-end approach. Ingenuity Pathway Analysis and the Dynamic Impact Approach analysis of differentially expressed genes (overall effect False Discovery Rate≤0.05) indicated that IMI induced an overall activation of inflammation at 12 h post-IMI and a strong inhibition of metabolism, especially related to lipid, glucose, and xenobiotics at 24 h post-IMI in liver. The data indicated in mammary tissue an overall induction of inflammatory response with little effect on metabolism at 24 h post-IMI. We identified a large number of up-stream regulators potentially involved in the response to IMI in both tissues but a relatively small core network of transcription factors controlling the response to IMI for liver whereas a large network in mammary tissue. Transcriptomic results in liver and mammary tissue were supported by changes in inflammatory and metabolic mediators in blood and milk. The analysis of potential cross-talk between the two tissues during IMI uncovered a large communication from the mammary tissue to the liver to coordinate the inflammatory response but a relatively small communication from the liver to the mammary tissue. Our results indicate a strong induction of the inflammatory response in mammary tissue and impairment of liver metabolism 24h post-IMI partly driven by the signaling from infected mammary tissue.

Bovine milk transcriptome analysis reveals microRNAs and RNU2 involved in mastitis

“…Interestingly, all of the disease categories associated with the miRNAs identified in this study included liver diseases (hepatocellular carcinoma in the cancer category, HEV in the infection category, and hepatitis B in the immune category). Gene expression profiling of liver tissues from dairy cows treated with intramammary Escherichia coli or lipopolysaccharide confirmed that the liver plays a major role in the acute‐phase response in E. coli ‐induced mastitis and that hepatic failure can be caused by mastitis or metritis , suggesting potential crosstalk between the liver and the mastitic mammary gland. HEV is the causative agent of hepatitis E, and anti‐HEV antibodies can be detected in humans and domestic and wild animals .…”

Integrating Sequence-based GWAS and RNA-Seq Provides Novel Insights into the Genetic Basis of Mastitis and Milk Production in Dairy Cattle

“…The approaches applied for RNA-Seq bioinformatics analyses have been previously described49. Briefly, the indices of the bovine reference genome (UMD3.1) were first built using the Build-Index function implemented in the Rsubread package51.…”

Transcriptome difference and potential crosstalk between liver and mammary tissue in mid-lactation primiparous dairy cows

“…An important role of the liver and the liver and mammary crosstalk during mastitis was uncovered by transcriptomic works in dairy cows [42] [13]. …”