TY - JOUR
T1 - Shear rate sensitizes bacterial pathogens to H2O2 stress
AU - Padron, Gilberto C.
AU - Shuppara, Alexander M.
AU - Sharma, Anuradha
AU - Koch, Matthias D.
AU - Palalay, Jessica Jae S.
AU - Radin, Jana N.
AU - Kehl-Fie, Thomas E.
AU - Imlay, James A.
AU - Sanfilippo, Joseph E.
N1 - ACKNOWLEDGMENTS. We thank Satish Nair, Nicholas Wu, Ido Golding, Raven Huang, Wilfred van der Donk, Nick Martin, Andrian Gutu, and Lisa Wiltbank for helpful discussions and comments on the manuscript. We would also like to thank Noah Miller for helpful discussions and comments regarding image analysis. This work was supported by NIH grant R01AI155611 to T.E.K.-F. This work was also supported by start-up funds from the University of Illinois at Urbana-Champaign and NIH grant K22AI151263 to J.E.S.
PY - 2023/3/8
Y1 - 2023/3/8
N2 - Cells regularly experience fluid flow in natural systems. However, most experimental systems rely on batch cell culture and fail to consider the effect of flow-driven dynamics on cell physiology. Using microfluidics and single-cell imaging, we discover that the interplay of physical shear rate (a measure of fluid flow) and chemical stress trigger a transcriptional response in the human pathogen Pseudomonas aeruginosa. In batch cell culture, cells protect themselves by quickly scavenging the ubiquitous chemical stressor hydrogen peroxide (H2O2) from the media. In microfluidic conditions, we observe that cell scavenging generates spatial gradients of H2O2. High shear rates replenish H2O2, abolish gradients, and generate a stress response. Combining mathematical simulations and biophysical experiments, we find that flow triggers an effect like "wind-chill"that sensitizes cells to H2O2 concentrations 100 to 1,000 times lower than traditionally studied in batch cell culture. Surprisingly, the shear rate and H2O2 concentration required to generate a transcriptional response closely match their respective values in the human bloodstream. Thus, our results explain a long-standing discrepancy between H2O2 levels in experimental and host environments. Finally, we demonstrate that the shear rate and H2O2 concentration found in the human bloodstream trigger gene expression in the blood-relevant human pathogen Staphylococcus aureus, suggesting that flow sensitizes bacteria to chemical stress in natural environments.
AB - Cells regularly experience fluid flow in natural systems. However, most experimental systems rely on batch cell culture and fail to consider the effect of flow-driven dynamics on cell physiology. Using microfluidics and single-cell imaging, we discover that the interplay of physical shear rate (a measure of fluid flow) and chemical stress trigger a transcriptional response in the human pathogen Pseudomonas aeruginosa. In batch cell culture, cells protect themselves by quickly scavenging the ubiquitous chemical stressor hydrogen peroxide (H2O2) from the media. In microfluidic conditions, we observe that cell scavenging generates spatial gradients of H2O2. High shear rates replenish H2O2, abolish gradients, and generate a stress response. Combining mathematical simulations and biophysical experiments, we find that flow triggers an effect like "wind-chill"that sensitizes cells to H2O2 concentrations 100 to 1,000 times lower than traditionally studied in batch cell culture. Surprisingly, the shear rate and H2O2 concentration required to generate a transcriptional response closely match their respective values in the human bloodstream. Thus, our results explain a long-standing discrepancy between H2O2 levels in experimental and host environments. Finally, we demonstrate that the shear rate and H2O2 concentration found in the human bloodstream trigger gene expression in the blood-relevant human pathogen Staphylococcus aureus, suggesting that flow sensitizes bacteria to chemical stress in natural environments.
KW - Pseudomonas aeruginosa
KW - hydrogen peroxide
KW - mechanosensing
KW - microfluidics
KW - shear flow
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U2 - 10.1073/pnas.2216774120
DO - 10.1073/pnas.2216774120
M3 - Article
C2 - 36888662
AN - SCOPUS:85150001372
SN - 0027-8424
VL - 120
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 11
M1 - e2216774120
ER -