Project description:Neonatal meningitis caused by Escherichia coli (NMEC) is a leading cause of morbidity and mortality in newborns, and its pathogenesis relies on the ability of the bacterium to adapt and survive in diverse host environments. Despite advances in neonatal care, significant gaps remain in our understanding of how NMEC reprogram their transcriptome to survive in physiologically relevant niches. This study investigated the transcriptomic profiles of E. coli strain RS218 (O18:H7:K1) in four under host-relevant environment —colonic fluid (CF), serum (S), human brain endothelial cells (HBECs) and cerebrospinal fluid (CSF)—to mimic the infection landscape of neonatal meningitis. High-throughput RNA sequencing (RNA-seq) was performed to profile NMEC’s transcriptomic responses in each niche, and differential gene expression analyses were conducted to identify enriched pathways.
Project description:Cronobacter (C.) is an important emerging opportunistic foodborne pathogen representing significant cause of mortality in neonatal patients with bacteremia and meningitis. Knowledge on the pathobiology of Cronobacter mediated meningitis has to a large extend been explored using in vitro models. To explore the innate immune response against the neonatal sepsis/meningitis causing isolate C. turicensis z3032 in vivo, zebrafish larvae (Danio rerio) were used as infection model. Following establishment of infection in zebrafish larvae with z3032, dual RNA-sequencing of host-pathogen was undertaken to profile RNA expression simultaneously in the pathogen and the head region of the zebrafish host.
Project description:Neonatal bacterial meningitis is a leading cause of infant morbidity and mortality, yet the molecular and cellular basis of the leptomeningeal response to infection remains poorly defined. Here, we study a mouse model of neonatal E. coli meningitis, combining celltype specific gene knockouts, leptomeningeal single-nucleus RNA sequencing, and endothelial cell culture to explore the role of Toll-like receptor 4 (TLR4) signaling in the host response to infection. Endothelial-specific deletion of Tlr4 dramatically reduced the inflammatory response in all leptomeningeal cell types and abrogated the infectionassociated increase in vascular permeability. In a brain endothelial cell line (bEnd.3 cells), exposure to E. coli triggered TLR4-dependent NF-κB activation, selective internalization of Claudin-5, and increased monolayer permeability, responses that were eliminated by Tlr4 knockout. RNA-seq showed that endothelial TLR4 controls an NF-κB–driven transcriptional program that orchestrates the leptomeningeal response to infection. These findings reframe the host response in neonatal Gram-negative bacterial meningitis as an endothelial-centric process.
