# UID-Dual Transcriptome Sequencing Analysis of the Molecular Interactions between Streptococcus agalactiae ATCC 27956 and Mammary Epithelial Cells

## TL;DR

This study uses transcriptome sequencing to explore how Streptococcus agalactiae interacts with cow mammary cells, revealing gene expression changes that could help treat mastitis.

## Contribution

The study identifies novel bacterial genes and host lncRNAs involved in immune disruption during S. agalactiae infection.

## Key findings

- Host cells showed 211 DEmRNAs and 452 DElncRNAs linked to immune and cancer-related processes.
- Bacterial genes tsf, prfB, and infC interfere with lncRNAs targeting RUNX1 and BCL2L11 in host cells.
- Bacteria disrupt host immune mechanisms by altering alternative splicing of lncRNA target genes.

## Abstract

The prevention and control of subclinical mastitis in dairy cows remains challenging. The pathogen Streptococcus agalactiae ATCC 27956 is a major Gram-positive bacterium that can damage host cells by infecting the mammary glands of cows. To analyze the molecular interactions during Streptococcus agalactiae infection, UID-Dual transcriptome sequencing was performed, and bioinformatics tools were used for analysis. Differentially expressed genes were mainly enriched in biological processes related to inflammation, immune response, and cancer. Streptococcus agalactiae can express genes that interfere with lncRNA in mammary epithelial cells, indirectly affecting the alternative splicing of lncRNA target genes and thus influencing normal cellular processes. This study provides potential therapeutic targets for the prevention and treatment of subclinical mastitis caused by Streptococcus agalactiae.

Streptococcus agalactiae ATCC 27956 is a highly contagious Gram-positive bacterium that causes mastitis, has a high infectivity for mammary epithelial cells, and becomes challenging to treat. However, the molecular interactions between it and mammary epithelial cells remain poorly understood. This study analyzed differential gene expression in mammary epithelial cells with varying levels of S. agalactiae infection using UID-Dual transcriptome sequencing and bioinformatics tools. This study identified 211 differentially expressed mRNAs (DEmRNAs) and 452 differentially expressed lncRNAs (DElncRNAs) in host cells, primarily enriched in anti-inflammatory responses, immune responses, and cancer-related processes. Additionally, 854 pathogen differentially expressed mRNAs (pDEmRNAs) were identified, mainly enriched in protein metabolism, gene expression, and biosynthesis processes. Mammary epithelial cells activate pathways, such as the ERK1/2 pathway, to produce reactive oxygen species (ROS) to eliminate bacteria. The bacteria disrupt the host’s innate immune mechanisms by interfering with the alternative splicing processes of mammary epithelial cells. Specifically, the bacterial genes of tsf, prfB, and infC can interfere with lncRNAs targeting RUNX1 and BCL2L11 in mammary epithelial cells, affecting the alternative splicing of target genes and altering normal molecular regulation.