GSE172013
MicroRNA expression profle in bovine mammary gland parenchyma infected by coagulase-positive or coagulase-negative staphylococci.
Purpose: The aim of the study was to compare the miRNA expression in non-infected (H) mammary gland parenchyma samples with that of glands infected with coagulase-positive staphy  lococci (CoPS) or coagulase-negative staphylococci (CoNS) using next-generation sequencing. Methods: miRNA-seq analysis was performed on mammary gland parenchyma samples collected from non-infected cows and those infected with coagulase-positive or -negative staphylococci. The miRNA libraries were constructed from total RNA using NEBNext Multiplex Small RNA Library Prep Set for Illumina (New England Biolabs) according to the manufacturer protocol. The quantification of the obtained libraries was performed on a Qubit 2.0 spectrophotometer (Invitrogen, Life Technologies), while a quality control on a TapeStation 2200 instrument (D1000 ScreenTape; Agilent). Single-end cycle sequencing was performed on the HiScanSQ platform (Illumina) with the use of TruSeq SR Cluster Kit v3- CBOT-HS and TruSeq SBS Kit v 3 - HS (Illumina). MicroRNA differentially expressed between investigated groups were identified with the DESeq2 software. Results: Comparing the CoPS and H groups, 256 known and 260 potentially new miRNAs were identifed, including 32 that were diferentially expressed (p=0.05), of which 27 were upregulated and 5 downregulated. Comparing the CoNS and H groups, 242 known and 171 new unique miRNAs were identifed: 10 were upregulated (p=0.05), and 2 downregulated (p=0.05). Comparing CoPS with H and CoNS with H, 5 Kyoto Encyclopedia of Genes and Genomes pathways were identifed; in both comparisons, diferentially-expressed miRNAs were associated with the bacterial invasion of epithelial cells and focal adhesion pathways. Four gene ontology terms were identifed in each comparison, with 2 being common to both immune system processes and signal transduction. Conclusions: Obtained results enabled us to characterize the miRNA profile of the mammary gland parenchyma tissue, not only the healthy one but also the tissue infected with coagulase-positive and negative staphylococci as well as allowed identification of miRNAs differing the examined groups and characteristic for the staphylococci infection. They also indicated that miRNAs, especially miR-99 and miR-182, play an essential role in the epigenetic regulation of a range of cellular processes, including immunological systems bacterial growth in dendritic cells and disease pathogenesis (miR-99), DNA repair and tumor progression (miR-182). Overall design: MicroRNA next generation sequencing of healthy mammary gland parenchyma samples and infected by coagulase-positive or coagulase-negative staphylococci performed using Illumina HiScanSQ.