| Author |
Schwarz, Eric G. Vercruysse, Maarten Macdonald, I. Cody Ralifo, Paul S. Yang, Jason H. Dwyer, Daniel J. Walker, Graham C. Martell, Jeffrey D. Belenky, Peter A. Braff, Dana Ye, Jonathan D. Allison, Kyle R. Ting, Alice Y. Chan, Clement T. Y. Collins, James J. Takahashi, Noriko Lobritz, Michael A. Pati, Mekhala Khalil, Ahmad S. |
| Description |
Author Affiliation: Dwyer DJ ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Belenky PA ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Yang JH ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); MacDonald IC ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Martell JD ( Departments of Chemistry and.); Takahashi N ( Biology, Massachusetts Institute of Technology, Cambridge, MA 02139); Chan CT ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Lobritz MA ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Braff D ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Schwarz EG ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Ye JD ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Pati M ( Chemistry, and.); Vercruysse M ( Biology, Massachusetts Institute of Technology, Cambridge, MA 02139); Ralifo PS ( Chemistry, and.); Allison KR ( Department of Systems Biology, Columbia University, New York, NY 10032); Khalil AS ( Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); Ting AY ( Departments of Chemistry and.); Walker GC ( Biology, Massachusetts Institute of Technology, Cambridge, MA 02139); Collins JJ ( Howard Hughes Medical Institute,Departments of Biomedical Engineering andCenter of Synthetic Biology, Boston University, Boston, MA 02215); |
| Abstract |
Deeper understanding of antibiotic-induced physiological responses is critical to identifying means for enhancing our current antibiotic arsenal. Bactericidal antibiotics with diverse targets have been hypothesized to kill bacteria, in part by inducing production of damaging reactive species. This notion has been supported by many groups but has been challenged recently. Here we robustly test the hypothesis using biochemical, enzymatic, and biophysical assays along with genetic and phenotypic experiments. We first used a novel intracellular $H_{2}O_{2}$ sensor, together with a chemically diverse panel of fluorescent dyes sensitive to an array of reactive species to demonstrate that antibiotics broadly induce redox stress. Subsequent gene-expression analyses reveal that complex antibiotic-induced oxidative stress responses are distinct from canonical responses generated by supraphysiological levels of $H_{2}O_{2}.$ We next developed a method to quantify cellular respiration dynamically and found that bactericidal antibiotics elevate oxygen consumption, indicating significant alterations to bacterial redox physiology. We further show that overexpression of catalase or DNA mismatch repair enzyme, MutS, and antioxidant pretreatment limit antibiotic lethality, indicating that reactive oxygen species causatively contribute to antibiotic killing. Critically, the killing efficacy of antibiotics was diminished under strict anaerobic conditions but could be enhanced by exposure to molecular oxygen or by the addition of alternative electron acceptors, indicating that environmental factors play a role in killing cells physiologically primed for death. This work provides direct evidence that, downstream of their target-specific interactions, bactericidal antibiotics induce complex redox alterations that contribute to cellular damage and death, thus supporting an evolving, expanded model of antibiotic lethality. |
