title: Reactive oxygen species do not contribute to ObgE*-mediated programmed cell death.
abstract: Programmed cell death (PCD) in bacteria is considered an important target for developing novel antimicrobials. Development of PCD-specific therapies requires a deeper understanding of what drives this process. We recently discovered a new mode of PCD in Escherichia coli that is triggered by expression of a mutant isoform of the essential ObgE protein, ObgE*. Our previous findings demonstrate that ObgE*-mediated cell death shares key characteristics with apoptosis in eukaryotic cells. It is well-known that reactive oxygen species (ROS) are formed during PCD in eukaryotes and play a pivotal role as signaling molecules in the progression of apoptosis. Therefore, we explored a possible role for ROS in bacterial killing by ObgE*. Using fluorescent probes and genetic reporters, we found that expression of ObgE* induces formation of ROS. Neutralizing ROS by chemical scavenging or by overproduction of ROS-neutralizing enzymes did not influence toxicity of ObgE*. Moreover, expression of ObgE* under anaerobic conditions proved to be as detrimental to bacterial viability as expression under aerobic conditions. In conclusion, ROS are byproducts of ObgE* expression that do not play a role in the execution or progression of ObgE*-mediated PCD. Targeted therapies should therefore look to exploit other aspects of ObgE*-mediated PCD.
authors.affiliation: Centre of Microbial and Plant Genetics, KU Leuven - University of Leuven, 3001 Leuven, Belgium.
authors.forename: Liselot
authors.initials: L
authors.lastname: Dewachter
authors.affiliation: Centre of Microbial and Plant Genetics, KU Leuven - University of Leuven, 3001 Leuven, Belgium.
authors.forename: Pauline
authors.initials: P
authors.lastname: Herpels
authors.affiliation: Centre of Microbial and Plant Genetics, KU Leuven - University of Leuven, 3001 Leuven, Belgium.
authors.forename: Natalie
authors.initials: N
authors.lastname: Verstraeten
authors.affiliation: Centre of Microbial and Plant Genetics, KU Leuven - University of Leuven, 3001 Leuven, Belgium.|Department of Life Science Technologies, Smart Systems and Emerging Technologies Unit, imec, 3001 Leuven, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Fauvart
authors.affiliation: Centre of Microbial and Plant Genetics, KU Leuven - University of Leuven, 3001 Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Michiels
mesh_terms: D017209:Apoptosis; D016923:Cell Death; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D017382:Reactive Oxygen Species; C491572:ObgE protein, E coli; D020559:Monomeric GTP-Binding Proteins