Insights into Intestinal Barrier Disruption During Long-Term Gut Chlamydia Colonization in Mice: A Single-Cell Transcriptomic Approach

Ziqing Wan¹Yicun Jiang¹Sheng Xie¹Jiao Wan¹Youyou Huang¹Luying Wang²Qi Zhang²Zengzi Zhou²Xin Sun²Chuqiang Shu^1*Tianyuan Zhang^3*Qi Tian^1*

• ¹Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
• ²Third Xiangya Hospital, Central South University, Changsha, Hunan Province, China
• ³School of Medicine, Shanghai Jiao Tong University, Shanghai, Shanghai Municipality, China

Chlamydia trachomatis, an intracellular pathogen, stands as the most prevalent sexually transmitted bacterial infection among women globally. Traditionally recognized as a genital pathogen, recent research indicates that the gastrointestinal tract may also act as a reservoir for its long-term colonization. However, the mechanisms underlying Chlamydia's ability to colonize in the gut remain poorly understood. This gap in knowledge limits our ability to develop effective treatments for longterm Chlamydia infections. In this study we utilized single-cell RNA sequencing to analyze the gene expression profiles and cellular heterogeneity of mouse colonic tissues during Chlamydia long-term colonization. This approach provided detailed insights into the transcriptional changes and cellular interactions involved in the long-term colonization of Chlamydia in the large intestine. Our results revealed significant alterations in the gene expression profiles of various intestinal cell populations, with distinct molecular pathways contributing to Chlamydia persistence in the large intestine. Notably, we observed a reduction in the expression of markers associated with epithelial tight junctions, indicating a potential breakdown of the intestinal epithelial barrier. This impairment may facilitate the penetration of Chlamydia into deeper tissues and contribute to the initiation of infection. We also found dysregulation of the transcriptional networks in goblet cells and an imbalance in communication between immune and epithelial cells. These observations suggest possible mechanisms through which Chlamydia may persist in the large intestine.