Biology subjects

Weber, T. M.

Publications and source records attributed to Weber, T. M..

3 recordsLinked to original sources

bioRxiv2025

Hoisted by Their Own Petard: Defeating Immunity Protein-Mediated Bacteriocin Resistance

The irresponsible use of antibiotics has led to an erratic spread of antimicrobial resistance (AMR) among bacterial pathogens. Without intervention, 10 million AMR-related deaths per year by 2050 are estimated by the WHO. Nonetheless, the development of novel antibiotics has almost come to a halt. In this context, naturally occurring narrow-spectrum antimicrobial proteins, known as bacteriocins, are promising alternatives to address the need for effective and selective antimicrobial treatments. However, the widespread distribution of cognate immunity proteins among bacteriocin producers vastly limits the natural antimicrobial spectrum against Gram-negative bacteria. On the example of pyocin S2 (PyoS2), an S-type HNH DNase bacteriocin targeting the opportunistic human pathogen Pseudomonas aeruginosa, this study demonstrates for the first time that a rationally introduced single mutation and chemical protein functionalisation at PyoS2s immunity protein exosite fully eradicate immunity protein-mediated resistance to pyocins in multidrug-resistant clinical P. aeruginosa isolates. The presented findings highlight a strategy to engineer bacteriocins from pathogenic Gram-negative bacteria with an extended antimicrobial spectrum, overruling the prevalent and predominant bacteriocin resistance mechanism of immunity protein binding. This strategy could expedite the development of engineered bacteriocins to expand our repository of antimicrobials to combat the worsening antimicrobial resistance crisis and avert a post-antibiotic era.

microbiology↗

bioRxiv2021

Vaccine Hyporesponse Induced By Individual Antibiotic Treatment In Mice And Non-Human Primates Is Diminished Upon Recovery Of The Gut Microbiome

Emerging evidence demonstrates a connection between microbiome composition and suboptimal response to vaccines (vaccine hyporesponse). Harnessing the interaction between microbes and the immune system could provide novel therapeutic strategies for improving vaccine response. Currently we do not fully understand the mechanisms and dynamics by which the microbiome influences vaccine response. Using both mouse and non-human primate models, we report that short-term oral treatment with a single antibiotic (vancomycin) results in disruption of the gut microbiome and this correlates with a decrease in systemic levels of antigen-specific IgG upon subsequent parenteral vaccination. We further show that recovery of microbial diversity before vaccination prevents antibiotic-induced vaccine hyporesponse, and that the antigen specific IgG response correlates with the recovery of microbiome diversity. RNA-sequencing analysis of small intestine, spleen, whole blood, and secondary lymphoid organs from antibiotic treated mice revealed a dramatic impact on the immune system, and a muted inflammatory signature is correlated with loss of bacteria from Lachnospiraceae, Ruminococcaceae, and Clostridiaceae. These results suggest that microbially modulated immune pathways may be leveraged to promote vaccine response and will inform future vaccine design and development strategies. ImportanceAntibiotic-induced gut microbiome disruption has been linked to reduced vaccine efficacy. Despite these observations, there remains a knowledge gap in the specific mechanisms by which antibiotics and the gut microbiome influence vaccine efficacy. We aim to contribute to the fields growing mechanistic understanding by presenting a detailed analysis of antibiotic treatment and recovery as it relates to vaccine response and the microbiome. Using animal models, we show that short-term antibiotic treatment prior to vaccination results in diminished vaccine-specific immune responses, and that these are correlated with specific microbiome signatures. We also demonstrate the converse, in which gut microbiome recovery can result in improved vaccine response. We further reveal that antibiotics can significantly alter multiple relevant immune pathways and this alteration in immune tone may contribute to the vaccine hyporesponse. We expect our findings will enable the continued prosecution of the role of the microbiome in modulating the host immune system.

immunology↗

bioRxiv2019

Pyocin S5 import into Pseudomonas aeruginosa reveals a generic mode of bacteriocin transport

Pyocin S5 (PyoS5) is a potent protein bacteriocin that eradicates the human pathogen P. aeruginosa in animal infection models, but its import mechanism is poorly understood. Here, using crystallography, biophysical and biochemical analysis and live-cell imaging, we define the entry process of PyoS5 and reveal links to the transport mechanisms of other bacteriocins. In addition to its C-terminal pore-forming domain, elongated PyoS5 comprises two novel tandemly repeated kinked three helix bundle domains that structure-based alignments identify as key import domains in other pyocins. The central domain binds the lipid-bound common polysaccharide antigen, allowing the pyocin to accumulate on the cell surface. The N-terminal domain binds the ferric pyochelin transporter FptA while its associated disordered region binds the inner membrane protein TonB1, which together drive import of the bacteriocin across the outer membrane. Finally, we identify the minimal requirements for sensitizing Escherichia coli towards PyoS5, as well as other pyocins, and suggest that a generic pathway likely underpins the import of all TonB-dependent bacteriocins across the outer membrane of Gram-negative bacteria.

biochemistry↗