Mammary Transcriptome Profile during Peak and Late Lactation Reveals Differentially Expression Genes Related to Inflammation and Immunity in Chinese Holstein

Abstract

Simple Summary: Milk somatic cell count, referring to the total number of somatic cells per milliliter of bovine milk, changes regularly during the lactation cycle. The somatic cell count of healthy cows is usually higher in late lactation than in peak lactation. When the inflammatory response in dairy cow mammary gland becomes more intense, the milk somatic cell count increases together with the reduction of milk quality and yield. Autoimmunity was thought to play an important role in the prevention of mastitis in late lactation of dairy cattle. However, the underlying mechanisms related to the gene expression levels during the process remain unknown. In this study, transcriptome sequencing was performed to screen the differentially expressed genes related to the inflammation and immunity in healthy Chinese Holstein mammary glands. Our findings are helpful to understand the physiological functions of mammary inflammation of Chinese Holstein during late lactation.Abstract: Somatic cell count (SCC) in milk is widely used in the dairy industry, as an indicator of the health of mammary gland. While the SCC of dairy cattle was higher in late lactation than in peak lactation, its association with gene expressions of mammary gland were largely unknown. In this study, a transcriptomic sequencing approach and bioinformatics analysis were used to investigate the differential expressed genes (DEGs) associated with inflammation and immunity between peak and late periods of lactation in Chinese Holstein. A total of 446 DEGs (padj < 0.05 and fold change >2) were identified, 50 of which belonged to seven pathways and five terms related to inflammation and immunity. Our data suggested that the activation of nuclear transcription factor-κB (NF-κB) pathway and Toll-like receptor signaling pathway caused inflammatory response, and the activation of chemokine signaling pathway and cytokine-cytokine receptor interaction signaling pathway caused a protective immune response to ensure dairy cows health during late lactation. Our findings deepen the understanding of the molecular mechanism and physiological functions of mammary inflammation in Chinese Holstein during late lactation.

Integrative Analysis of miRNA and mRNA Expression Profiles in Mammary Glands of Holstein Cows Artificially Infected with Staphylococcus aureus

“…With the online software TargetScan ( , accessed on 6 November 2020), the potential target genes of DE miRNAs with more significant expression levels ( p ≤ 0.05 and |log 2 FC| ≥ 2) were predicted and intersected, with the DEGs identified by microarray test ( p ≤ 0.05 and |log 2 FC| ≥ 2). Then, the miRNA–mRNA interaction networks were constructed and visualized with the DE miRNAs and screened genes by Cytoscape (v3.7.2) [ 65 ].…”

“…DEGs regulated by DE miRNAs were screened to further understand their biological and metabolic pathways. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were respectively performed with the DAVID 6.8 ( , accessed on 6 November 2020) and KOBAS 3.0 ( , accessed on 6 November 2020) using R based on the hypergeometric distribution [ 65 ]. Then, the GO terms and KEGG pathways with adjusted p ≤ 0.05 were significantly enriched in DEGs or the miRNA target genes.…”

Directed Expression of Tracheal Antimicrobial Peptide as a Treatment for Bovine-Associated Staphylococcus Aureus-Induced Mastitis in Mice

“…qRT-PCR was performed using the LightCycler ® 480 System (Roche, Basel, Switzerland) with High Capacity cDNA Reverse Transcription Kits (Applied Biosystems, Foster City, USA) and SYBR Premix EX Taq (Takara, Beijing, China) according to the manufacturer's instructions. The relative expression levels of TAP were calculated with the 2 −ΔΔCt method ( 23 ).…”

Integrative Analysis of miRNA and mRNA Expression Profiles in Mammary Glands of Holstein Cows Artificially&nbsp;Infected with Staphylococcus Aureus

“…DEGs regulated by DE miRNAs were screened to further understand their biological and metabolic pathways. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were respectively performed with the DAVID 6.8 (https://david.ncifcrf.gov/) and KOBAS 3.0 (http://kobas.cbi.pku.edu.cn/index.php) using R based on the hypergeometric distribution [47]. Then the GO terms and KEGG pathways with P-value ≤ 0.05 were signi cantly enriched in DEGs or the miRNA target genes.…”

“…With the online software TargetScan (www.targetscan.org), the potential target genes of DE miRNAs (P ≤ 0.05 and fold change ≥ 4) were predicted and intersected with the DEGs identi ed by microarray test (P ≤ 0.05 and fold change ≥ 4). Then the miRNA-mRNA interaction networks were constructed and visualized with the DE miRNAs and screened genes by String (v11.0) database and Cytoscape (v3.7.2), respectively [47].…”