Helicobacter pylori outer membrane vesicles induce astrocyte reactivity through nuclear factor-κappa B activation and cause neuronal damage in vivo in a murine model
Journal
Journal of Neuroinflammation
ISSN
1742-2094
Date Issued
2023
Author(s)
Esteban Palacios
Lorena Lobos-González
Simón Guerrero
Marcelo J. Kogan
Baohai Shao
Jay W. Heinecke
Andrew F. G. Quest
Lisette Leyton
Manuel Valenzuela-Valderrama
Type
Resource Types::text::journal::journal article
URL Institutional Repository
Abstract
<jats:title>Abstract</jats:title><jats:sec>
<jats:title>Background</jats:title>
<jats:p><jats:italic>Helicobacter pylori (Hp)</jats:italic> infects the stomach of 50% of the world’s population. Importantly, chronic infection by this bacterium correlates with the appearance of several extra-gastric pathologies, including neurodegenerative diseases. In such conditions, brain astrocytes become reactive and neurotoxic. However, it is still unclear whether this highly prevalent bacterium or the nanosized outer membrane vesicles (OMVs) they produce, can reach the brain, thus affecting neurons/astrocytes. Here, we evaluated the effects of <jats:italic>Hp</jats:italic> OMVs on astrocytes and neurons in vivo and in vitro.</jats:p>
</jats:sec><jats:sec>
<jats:title>Methods</jats:title>
<jats:p>Purified OMVs were characterized by mass spectrometry (MS/MS). Labeled OMVs were administered orally or injected into the mouse tail vein to study OMV-brain distribution. By immunofluorescence of tissue samples, we evaluated: GFAP (astrocytes), βIII tubulin (neurons), and urease (OMVs). The in vitro effect of OMVs in astrocytes was assessed by monitoring NF-κB activation, expression of reactivity markers, cytokines in astrocyte-conditioned medium (ACM), and neuronal cell viability.</jats:p>
</jats:sec><jats:sec>
<jats:title>Results</jats:title>
<jats:p>Urease and GroEL were prominent proteins in OMVs. Urease (OMVs) was present in the mouse brain and its detection coincided with astrocyte reactivity and neuronal damage. In vitro, OMVs induced astrocyte reactivity by increasing the intermediate filament proteins GFAP and vimentin, the plasma membrane α<jats:sub>V</jats:sub>β<jats:sub>3</jats:sub> integrin, and the hemichannel connexin 43. OMVs also produced neurotoxic factors and promoted the release of IFNγ in a manner dependent on the activation of the transcription factor NF-κB. Surface antigens on reactive astrocytes, as well as secreted factors in response to OMVs, were shown to inhibit neurite outgrowth and damage neurons.</jats:p>
</jats:sec><jats:sec>
<jats:title>Conclusions</jats:title>
<jats:p>OMVs administered orally or injected into the mouse bloodstream reach the brain, altering astrocyte function and promoting neuronal damage in vivo. The effects of OMVs on astrocytes were confirmed in vitro and shown to be NF-κB-dependent. These findings suggest that <jats:italic>Hp</jats:italic> could trigger systemic effects by releasing nanosized vesicles that cross epithelial barriers and access the CNS, thus altering brain cells.</jats:p>
</jats:sec>
<jats:title>Background</jats:title>
<jats:p><jats:italic>Helicobacter pylori (Hp)</jats:italic> infects the stomach of 50% of the world’s population. Importantly, chronic infection by this bacterium correlates with the appearance of several extra-gastric pathologies, including neurodegenerative diseases. In such conditions, brain astrocytes become reactive and neurotoxic. However, it is still unclear whether this highly prevalent bacterium or the nanosized outer membrane vesicles (OMVs) they produce, can reach the brain, thus affecting neurons/astrocytes. Here, we evaluated the effects of <jats:italic>Hp</jats:italic> OMVs on astrocytes and neurons in vivo and in vitro.</jats:p>
</jats:sec><jats:sec>
<jats:title>Methods</jats:title>
<jats:p>Purified OMVs were characterized by mass spectrometry (MS/MS). Labeled OMVs were administered orally or injected into the mouse tail vein to study OMV-brain distribution. By immunofluorescence of tissue samples, we evaluated: GFAP (astrocytes), βIII tubulin (neurons), and urease (OMVs). The in vitro effect of OMVs in astrocytes was assessed by monitoring NF-κB activation, expression of reactivity markers, cytokines in astrocyte-conditioned medium (ACM), and neuronal cell viability.</jats:p>
</jats:sec><jats:sec>
<jats:title>Results</jats:title>
<jats:p>Urease and GroEL were prominent proteins in OMVs. Urease (OMVs) was present in the mouse brain and its detection coincided with astrocyte reactivity and neuronal damage. In vitro, OMVs induced astrocyte reactivity by increasing the intermediate filament proteins GFAP and vimentin, the plasma membrane α<jats:sub>V</jats:sub>β<jats:sub>3</jats:sub> integrin, and the hemichannel connexin 43. OMVs also produced neurotoxic factors and promoted the release of IFNγ in a manner dependent on the activation of the transcription factor NF-κB. Surface antigens on reactive astrocytes, as well as secreted factors in response to OMVs, were shown to inhibit neurite outgrowth and damage neurons.</jats:p>
</jats:sec><jats:sec>
<jats:title>Conclusions</jats:title>
<jats:p>OMVs administered orally or injected into the mouse bloodstream reach the brain, altering astrocyte function and promoting neuronal damage in vivo. The effects of OMVs on astrocytes were confirmed in vitro and shown to be NF-κB-dependent. These findings suggest that <jats:italic>Hp</jats:italic> could trigger systemic effects by releasing nanosized vesicles that cross epithelial barriers and access the CNS, thus altering brain cells.</jats:p>
</jats:sec>
Cite this document
Palacios, E., Lobos-González, L., Guerrero, S., Kogan, M. J., Shao, B., Heinecke, J. W., Quest, A. F. G., Leyton, L., & Valenzuela-Valderrama, M. (2023). Helicobacter pylori outer membrane vesicles induce astrocyte reactivity through nuclear factor-κappa B activation and cause neuronal damage in vivo in a murine model. Journal of Neuroinflammation, 20(1), 66. https://doi.org/10.1186/s12974-023-02728-7
Project(s)
Subjects
astrogliosis
;
brain damage
;
helicobacter pylori
;
inflammation
;
nf-κb
;
omvs
;
animals
;
astrocytes
;
complement factor b
;
disease models, animal
;
helicobacter pylori
;
mice
;
neurons
;
nf-kappa b
;
tandem mass spectrometry
;
urease
;
beta tubulin
;
connexin 43
;
glial fibrillary acidic protein
;
immunoglobulin enhancer binding protein
;
urease
;
vimentin
;
vitronectin receptor
;
alternative complement pathway c3 c5 convertase
;
immunoglobulin enhancer binding protein
;
urease
;
animal cell
;
animal experiment
;
animal model
;
animal tissue
;
article
;
astrocyte
;
bacterial outer membrane
;
bacterial strain
;
brain damage
;
cell damage
;
cell differentiation
;
cell labeling
;
cell membrane
;
cell migration
;
cell size
;
cell vacuole
;
cell viability
;
controlled study
;
flow cytometry
;
helicobacter pylori
;
immunoblotting
;
immunofluorescence
;
in vitro study
;
in vivo study
;
male
;
mass spectrometry
;
mouse
;
nerve cell
;
nonhuman
;
protein expression
;
rat
;
animal
;
astrocyte
;
disease model
;
metabolism
;
nerve cell
;
tandem mass spectrometry