PT  - JOURNAL ARTICLE
AU  - Eloise J O’Donoghue
AU  - Douglas F. Browning
AU  - Ewa Bielska
AU  - Luke Alderwick
AU  - Sara Jabbari
AU  - Anne Marie Krachler
TI  - Lipopolysaccharide composition determines the preferred route and entry kinetics of bacterial outer membrane vesicles into host cells
AID  - 10.1101/084848
DP  - 2016 Jan 01
TA  - bioRxiv
PG  - 084848
4099  - http://biorxiv.org/content/early/2016/11/01/084848.short
4100  - http://biorxiv.org/content/early/2016/11/01/084848.full
AB  - Outer membrane vesicles are microvesicles shed by Gram-negative bacteria and play important roles in immune priming and disease pathogenesis. However, our current mechanistic understanding of vesicle - host cell interactions is limited by a lack of methods to study the kinetics of vesicle entry and cargo delivery to host cells in real-time. Here, we describe a highly sensitive method to study the kinetics of vesicle entry into host cells in real-time using a genetically encoded probe targeted to vesicles. We found that route of vesicular uptake, and thus entry kinetics and efficiency of cargo release, are determined by the chemical composition of the bacterial lipopolysaccharide. The presence of O-antigen facilitates receptor-independent entry, which enhances both rate and efficiency of cargo uptake by host cells. Collectively, our findings highlight the chemical composition of the bacterial cell wall as a major determinant of secretion-independent delivery of virulence factors during Gram-negative infections.