Prevalent gut phages encode modular adhesins mediating epithelial binding and endoplasmic reticulum trafficking

Area of Science:

• Microbiology
• Virology
• Immunology

Background:

• Bacteriophages are vital to the human microbiome, with therapeutic potential.
• The physical interactions between phages and mammalian cells are not well understood.

Purpose of the Study:

• To develop a high-throughput platform for identifying phages that adhere to epithelial cells.
• To identify the specific proteins mediating phage-epithelial interactions.

Main Methods:

• Developed a high-throughput screening platform to detect phage adherence to epithelial layers.
• Utilized phage display to identify and characterize immunoglobulin (Ig)-like domain proteins responsible for binding.
• In vitro and in vivo studies in mice to assess phage binding, internalization, and gut retention.

Main Results:

• Identified Ig-like domain proteins on phages that mediate epithelial binding and internalization.
• Engineered phages displaying these adhesins showed enhanced binding and retention in the mouse gut.
• Found that abundant human gut phages, including crAss-like phages, encode these adhesins.
• Internalized phages traffic through the Golgi apparatus to the endoplasmic reticulum, indicating non-degradative pathways.

Conclusions:

• Widespread phage-human epithelial interactions exist within the human gut virome.
• Phage adhesins are key mediators of these interactions, impacting phage behavior in vivo.
• These findings have significant implications for understanding phage ecology and developing novel phage-based therapies.