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:The blood-brain barrier (BBB) serves as a physiological and functional protective barrier between the brain parenchyma and the peripheral circulatory system, which protects the brain from bloodborne agents, including pathogens and toxins. Bacterial meningitis, a devastating disease occurring worldwide, remains a major cause of high mortality and morbidity, which can trigger BBB disruption and intense intracerebral inflammatory responses. Using single-cell RNA sequencing (scRNA-seq), we show that during neonatal meningitis Escherichia coli (NMEC) challenges, brain endothelial cells undergo pyroptosis and trigger the pyroptotic cascade through intercellular interactions, leading to inflammatory disruption of BBB and strong immune response within the brain. Analyses of the scRNA-seq dataset demonstrate that brian endothelial cells and microglia display the most sensitive to bacterial responses, and the crosstalk between brain vascular cells and immune cells remodels the central nervous system immune microenvironment. We employed a single-cell sequencing approach using 10x Genomics scRNAseq to study neonatal meningitis caused by Escherichia coli (NMEC) infection in mice. This study reveals that NMEC triggers pyroptosis in cerebral cortex cells, leading to inflammatory disruption of the BBB, activation of the apoptotic cascade, and triggering a strong immune response within the brain, disrupting the central nervous system's immune microenvironment. It helps us understand the immunopathological mechanisms of NMEC-induced meningitis and provides a theoretical basis for developing innovative therapeutic strategies targeting the function regulation of cortical cells or microglia and the apoptotic process, thus opening up new avenues for the prevention and treatment of neonatal meningitis.
Project description:Preterm birth is currently the leading cause of neonatal morbidity and mortality. Genetic, immunological and infectious causes are suspected. Preterm infants have a higher risk of severe bacterial neonatal infections, most of which are caused by Escherichia coli an in particular E. coli K1strains. Women with history of preterm delivery have a high risk of recurrence and therefore constitute a target population for the development of vaccine against E. coli neonatal infections. Here, we characterized the immunological, microbiological and protective properties of a live attenuated vaccine candidate in adult female mice and their pups against after a challenge by K1 and non-K1 strains of E. coli. Our results show that the E. coli K1 E11 aroA vaccine induces strong immunity, driven by polyclonal bactericidal antibodies. In our model of meningitis, pups born to mothers immunized before mating were well protected against various K1 and non-K1 strains of E. coli. Given the very high mortality rate and the neurological sequalae associated with neonatal E. coli K1 meningitis, our results constitute preclinical proof of concept for the development of a live attenuated vaccine against severe E. coli infections in women at risk of preterm delivery.
