Functional metagenomics: a high throughput screening method to decipher microbiota-driven NF-κB modulation in the...

Area of Science:

• Microbiology
• Immunology
• Molecular Biology

Background:

• The human intestinal microbiota influences mucosal immune responses.
• Understanding interactions between intestinal epithelial cells (IECs) and commensal bacteria is crucial.
• Metagenomics provides access to genomes of uncultured microbes.

Purpose of the Study:

• To identify bacterial genes involved in regulating NF-κB signaling in IECs.
• To develop a functional metagenomic approach for studying IEC-bacterial interactions.
• To screen human intestinal microbiota metagenomic libraries for NF-κB modulators.

Main Methods:

• Established a high-throughput cell-based screening assay using a reporter-gene strategy.
• Utilized a reporter clone (HT-29/kb-seap-25) transfected with SEAP gene under NF-κB control.
• Screened metagenomic libraries from Crohn's disease patients and analyzed positive clones via sequencing and mutagenesis.

Main Results:

• The reporter system successfully detected NF-κB pathway activation by TNF-α and IL-1β.
• Screening identified 171 modulating clones out of 2640, including one stimulatory clone (52B7).
• Clone 52B7, potentially from a novel Bacteroides strain, showed identified loci for an ABC transport system and a putative lipoprotein.

Conclusions:

• A robust high-throughput screening assay for metagenomic libraries was established.
• This assay enables the study of bacteria-driven NF-κB regulation in IECs.
• The approach facilitates the identification of bacterial strains and molecular patterns with therapeutic potential.