Availability of iron ions impacts physicochemical properties and proteome of outer membrane vesicles released by Neisseria gonorrhoeae

Abstract

Outer membrane vesicles (OMVs) are bilayer structures released by bacteria for various purposes, e.g., response to environmental factors, bacterial communication, and interactions with host cells. One of the environmental variables bacteria need to react is the amount and availability of iron, a crucial element for bacteria biology. We have investigated the impact of the iron amount and availability on OMV secretion by pathogenic Neisseria gonorrhoeae, which, depending on the infection site, challenges different iron availability. N. gonorrhoeae releases OMVs in iron starvation and repletion growth environments. However, OMVs differed in physicochemical features and proteome according to iron amount and availability during the bacteria growth, as was analyzed by Liquid Chromatography-Tandem Mass Spectrometry, Infrared spectroscopy with a Fourier transform infrared spectrometer, and Atomic Force Microscopy. OMVs from iron starvation and repletion conditions had a higher variation in size, different flexibility, and different membrane protein and lipid components than OMVs isolated from control growth conditions. These OMVs also varied qualitatively and quantitatively in their total proteome composition and contained proteins unique for iron starvation and repletion conditions. Thus, the modulation of OMVs' properties seems to be a part of N. gonorrhoeae adaptation to surroundings and indicates a new direction of antigonococcal proceeding.

Effects of a N-Maleimide-derivatized Phosphatidylethanolamine on the Architecture and Properties of Lipid Bilayers

“…This is the case of the calorimetric data obtained when PE or PE-mal were mixed at 30 mol% with the bilayer-forming DPPC (Figure 1) or the IR spectral data of methylene stretching vibrations of the ePC:DOPE:PI (35:55:10) or ePC:DOPE:DOPEmal:PI (35:25:30:10) bilayers (Figure 5C-F). Differential scanning calorimetry and methylene IR stretching vibrations often give rise to concordant results, in spite of their very diverse physical foundations, see, e.g., [22,23]. Importantly, DOPE-mal was as inactive as DOPE in facilitating vesicle membrane permeability (Figures 6, 7 and S1).…”

The Role of Bacterial Extracellular Vesicles in the Immune Response to Pathogens, and Therapeutic Opportunities

“…This response has been observed in most of the Gram-negative bacteria, such as H. pylori [ 53 ], Salmonella spp. [ 54 ], Neisseria gonorrhoeae [ 55 ], A. baumannii [ 56 , 57 ], or P. aeruginosa [ 58 ].…”

“…Iron is an indispensable microelement for bacterial growth. Some studies using minimal culture media devoid of this element increase vesiculation in N. gonorrhoeae [ 55 ], A. baumannii [ 56 ], or E. coli [ 50 ]. In the EVs of some of these bacteria, iron capture molecules such as enterobactin have been identified, indicating that one of the functions of vesiculation is the capture of nutrients [ 56 ].…”