d-Serine induces distinct transcriptomes in diverse Escherichia coli pathotypes

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Molecular Biology

Background:

• Pathogenic bacteria interpret environmental signals for niche specificity.
• Responses of niche-specific pathogens to common host signals are not well understood.
• D-serine (d-ser) is a toxic metabolite found at variable concentrations in the human host.

Purpose of the Study:

• To investigate the global transcriptional response of three Escherichia coli pathotypes (EHEC, UPEC, NMEC) to d-serine.
• To understand how distinct E. coli pathotypes respond to a common host metabolite.
• To explore the role of d-serine in niche adaptation.

Main Methods:

• Comparative transcriptomic analysis of EHEC, UPEC, and NMEC exposed to d-serine.
• Identification of differentially expressed genes across pathotypes.
• Analysis of the dsdCXA locus and DsdC activator in response to d-serine accumulation.

Main Results:

• No single differentially expressed gene was common to all three E. coli pathotypes.
• UPEC and NMEC showed induction of ribosome-associated genes; EHEC and UPEC showed induction of purine metabolism genes.
• Transcriptome alterations in UPEC correlated with urinary transcriptome data, suggesting d-serine sensing in urinary niche adaptation.

Conclusions:

• Diverse E. coli pathotypes exhibit distinct transcriptional responses to the common metabolite d-serine.
• D-serine sensing and metabolism play a significant role in the niche selectivity of pathogenic bacteria.
• These findings have implications for understanding bacterial adaptation and pathogenesis in different host environments.