High dissolved oxygen tension triggers outer membrane vesicle formation by Neisseria meningitidis

Matthias J.H. Gerritzen, Ronald H.W. Maas, Jan van den IJssel, Lonneke van Keulen, Dirk E. Martens, René H. Wijffels, Michiel Stork

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background: Outer membrane vesicles (OMVs) are nanoparticles released by Gram-negative bacteria and can be used as vaccines. Often, detergents are used to promote release of OMVs and to remove the toxic lipopolysaccharides. Lipopolysaccharides can be detoxified by genetic modification such that vesicles spontaneously produced by bacteria can be directly used as vaccines. The use of spontaneous OMVs has the advantage that no separate extraction step is required in the purification process. However, the productivity of spontaneous OMVs by bacteria at optimal growth conditions is low. One of many methods for increasing OMV formation is to reduce the linkage of the outer membrane to the peptidoglycan layer by knocking out the rmpM gene. A previous study showed that for Neisseria meningitidis this resulted in release of more OMVs. Furthermore, cysteine depletion was found to trigger OMV release and at the same time cause reduced growth and oxidative stress responses. Here we study the effect of growth rate and oxidative stress on OMV release. Results: First, we identified using chemostat and accelerostat cultures of N. meningitidis that increasing the growth rate from 0.03 to 0.18 h-1 has a limited effect on OMV productivity. Thus, we hypothesized that oxidative stress is the trigger for OMV release and that oxidative stress can be introduced directly by increasing the dissolved oxygen tension of bacterial cultures. Slowly increasing oxygen concentrations in a N. meningitidis changestat showed that an increase from 30 to 150% air saturation improved OMV productivity four-fold. Batch cultures controlled at 100% air saturation increased OMV productivity three-fold over batch cultures controlled at 30% air saturation. Conclusion: Increased dissolved oxygen tension induces the release of outer membrane vesicles in N. meningitidis cultures. Since oxygen concentration is a well-controlled process parameter of bacterial cultures, this trigger can be applied as a convenient process parameter to induce OMV release in bacterial cultures. Improved productivity of OMVs not only improves the production costs of OMVs as vaccines, it also facilitates the use of OMVs as adjuvants, enzyme carriers, or cell-specific drug delivery vehicles.

LanguageEnglish
Article number157
JournalMicrobial Cell Factories
Volume17
Issue number1
DOIs
Publication statusPublished - 3 Oct 2018

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Neisseria meningitidis
Dissolved oxygen
Oxygen
Membranes
Oxidative stress
Productivity
Vaccines
Oxidative Stress
Bacteria
Batch Cell Culture Techniques
Air
Growth
Lipopolysaccharides
Bacterial Physiological Phenomena
Chemostats
Peptidoglycan
Poisons
Detergents

Keywords

  • Accelerostat
  • Dissolved oxygen changestat
  • Neisseria meningitidis
  • Outer membrane vesicles
  • Oxidative stress

Cite this

@article{cc5181e09e0144a5a0780bcdef348719,
title = "High dissolved oxygen tension triggers outer membrane vesicle formation by Neisseria meningitidis",
abstract = "Background: Outer membrane vesicles (OMVs) are nanoparticles released by Gram-negative bacteria and can be used as vaccines. Often, detergents are used to promote release of OMVs and to remove the toxic lipopolysaccharides. Lipopolysaccharides can be detoxified by genetic modification such that vesicles spontaneously produced by bacteria can be directly used as vaccines. The use of spontaneous OMVs has the advantage that no separate extraction step is required in the purification process. However, the productivity of spontaneous OMVs by bacteria at optimal growth conditions is low. One of many methods for increasing OMV formation is to reduce the linkage of the outer membrane to the peptidoglycan layer by knocking out the rmpM gene. A previous study showed that for Neisseria meningitidis this resulted in release of more OMVs. Furthermore, cysteine depletion was found to trigger OMV release and at the same time cause reduced growth and oxidative stress responses. Here we study the effect of growth rate and oxidative stress on OMV release. Results: First, we identified using chemostat and accelerostat cultures of N. meningitidis that increasing the growth rate from 0.03 to 0.18 h-1 has a limited effect on OMV productivity. Thus, we hypothesized that oxidative stress is the trigger for OMV release and that oxidative stress can be introduced directly by increasing the dissolved oxygen tension of bacterial cultures. Slowly increasing oxygen concentrations in a N. meningitidis changestat showed that an increase from 30 to 150{\%} air saturation improved OMV productivity four-fold. Batch cultures controlled at 100{\%} air saturation increased OMV productivity three-fold over batch cultures controlled at 30{\%} air saturation. Conclusion: Increased dissolved oxygen tension induces the release of outer membrane vesicles in N. meningitidis cultures. Since oxygen concentration is a well-controlled process parameter of bacterial cultures, this trigger can be applied as a convenient process parameter to induce OMV release in bacterial cultures. Improved productivity of OMVs not only improves the production costs of OMVs as vaccines, it also facilitates the use of OMVs as adjuvants, enzyme carriers, or cell-specific drug delivery vehicles.",
keywords = "Accelerostat, Dissolved oxygen changestat, Neisseria meningitidis, Outer membrane vesicles, Oxidative stress",
author = "Gerritzen, {Matthias J.H.} and Maas, {Ronald H.W.} and {van den IJssel}, Jan and {van Keulen}, Lonneke and Martens, {Dirk E.} and Wijffels, {Ren{\'e} H.} and Michiel Stork",
year = "2018",
month = "10",
day = "3",
doi = "10.1186/s12934-018-1007-7",
language = "English",
volume = "17",
journal = "Microbial Cell Factories",
issn = "1475-2859",
publisher = "Springer Verlag",
number = "1",

}

High dissolved oxygen tension triggers outer membrane vesicle formation by Neisseria meningitidis. / Gerritzen, Matthias J.H.; Maas, Ronald H.W.; van den IJssel, Jan; van Keulen, Lonneke; Martens, Dirk E.; Wijffels, René H.; Stork, Michiel.

In: Microbial Cell Factories, Vol. 17, No. 1, 157, 03.10.2018.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - High dissolved oxygen tension triggers outer membrane vesicle formation by Neisseria meningitidis

AU - Gerritzen, Matthias J.H.

AU - Maas, Ronald H.W.

AU - van den IJssel, Jan

AU - van Keulen, Lonneke

AU - Martens, Dirk E.

AU - Wijffels, René H.

AU - Stork, Michiel

PY - 2018/10/3

Y1 - 2018/10/3

N2 - Background: Outer membrane vesicles (OMVs) are nanoparticles released by Gram-negative bacteria and can be used as vaccines. Often, detergents are used to promote release of OMVs and to remove the toxic lipopolysaccharides. Lipopolysaccharides can be detoxified by genetic modification such that vesicles spontaneously produced by bacteria can be directly used as vaccines. The use of spontaneous OMVs has the advantage that no separate extraction step is required in the purification process. However, the productivity of spontaneous OMVs by bacteria at optimal growth conditions is low. One of many methods for increasing OMV formation is to reduce the linkage of the outer membrane to the peptidoglycan layer by knocking out the rmpM gene. A previous study showed that for Neisseria meningitidis this resulted in release of more OMVs. Furthermore, cysteine depletion was found to trigger OMV release and at the same time cause reduced growth and oxidative stress responses. Here we study the effect of growth rate and oxidative stress on OMV release. Results: First, we identified using chemostat and accelerostat cultures of N. meningitidis that increasing the growth rate from 0.03 to 0.18 h-1 has a limited effect on OMV productivity. Thus, we hypothesized that oxidative stress is the trigger for OMV release and that oxidative stress can be introduced directly by increasing the dissolved oxygen tension of bacterial cultures. Slowly increasing oxygen concentrations in a N. meningitidis changestat showed that an increase from 30 to 150% air saturation improved OMV productivity four-fold. Batch cultures controlled at 100% air saturation increased OMV productivity three-fold over batch cultures controlled at 30% air saturation. Conclusion: Increased dissolved oxygen tension induces the release of outer membrane vesicles in N. meningitidis cultures. Since oxygen concentration is a well-controlled process parameter of bacterial cultures, this trigger can be applied as a convenient process parameter to induce OMV release in bacterial cultures. Improved productivity of OMVs not only improves the production costs of OMVs as vaccines, it also facilitates the use of OMVs as adjuvants, enzyme carriers, or cell-specific drug delivery vehicles.

AB - Background: Outer membrane vesicles (OMVs) are nanoparticles released by Gram-negative bacteria and can be used as vaccines. Often, detergents are used to promote release of OMVs and to remove the toxic lipopolysaccharides. Lipopolysaccharides can be detoxified by genetic modification such that vesicles spontaneously produced by bacteria can be directly used as vaccines. The use of spontaneous OMVs has the advantage that no separate extraction step is required in the purification process. However, the productivity of spontaneous OMVs by bacteria at optimal growth conditions is low. One of many methods for increasing OMV formation is to reduce the linkage of the outer membrane to the peptidoglycan layer by knocking out the rmpM gene. A previous study showed that for Neisseria meningitidis this resulted in release of more OMVs. Furthermore, cysteine depletion was found to trigger OMV release and at the same time cause reduced growth and oxidative stress responses. Here we study the effect of growth rate and oxidative stress on OMV release. Results: First, we identified using chemostat and accelerostat cultures of N. meningitidis that increasing the growth rate from 0.03 to 0.18 h-1 has a limited effect on OMV productivity. Thus, we hypothesized that oxidative stress is the trigger for OMV release and that oxidative stress can be introduced directly by increasing the dissolved oxygen tension of bacterial cultures. Slowly increasing oxygen concentrations in a N. meningitidis changestat showed that an increase from 30 to 150% air saturation improved OMV productivity four-fold. Batch cultures controlled at 100% air saturation increased OMV productivity three-fold over batch cultures controlled at 30% air saturation. Conclusion: Increased dissolved oxygen tension induces the release of outer membrane vesicles in N. meningitidis cultures. Since oxygen concentration is a well-controlled process parameter of bacterial cultures, this trigger can be applied as a convenient process parameter to induce OMV release in bacterial cultures. Improved productivity of OMVs not only improves the production costs of OMVs as vaccines, it also facilitates the use of OMVs as adjuvants, enzyme carriers, or cell-specific drug delivery vehicles.

KW - Accelerostat

KW - Dissolved oxygen changestat

KW - Neisseria meningitidis

KW - Outer membrane vesicles

KW - Oxidative stress

U2 - 10.1186/s12934-018-1007-7

DO - 10.1186/s12934-018-1007-7

M3 - Article

VL - 17

JO - Microbial Cell Factories

T2 - Microbial Cell Factories

JF - Microbial Cell Factories

SN - 1475-2859

IS - 1

M1 - 157

ER -