Helicobacter Pylori-Vacuolating Cytotoxin A Inducing Neurotoxic Neuroinflammation in Human Stomach-Brain Axis

Abstract

Abstract Background Several epidemiological research have recommended a potential link between Helicobacter pylori infection and neurodegeneration, including Alzheimer’s and Parkinson’s diseases. However, the current research could not fully provide a comprehensive understanding of this association due to the absence of suitable model systems for studying multi-organ interactions and multiplex effects upon Helicobacter pylori infection. Results Here, we recapitulated a human stomach-brain axis by treating human in vitro cellular models with Helicobacter pylori’s cell-free supernatant (HPCFS). We first confirmed that HPCFS disrupted the tightness of gut and brain barriers via Vacuolating cytotoxin A (VacA) binding to Low-density Lipoprotein receptor 1 (LRP1) receptor, leading to reduced tight junction proteins and transmembrane electrical resistance. Blood-brain barrier-penetrating VacA toxin in HPCFS activated central innate immune cells, evidenced by the increased expression of inflammatory markers, oxidative stress, the release of neurotoxic factors, and inflammatory soluble markers, such as NO, IL-8, IL-18 from microglia as well as H2O2, IL-6, and IL-16 from astrocytes. VacA toxin hindered microglial amyloid-beta phagocytosis of amyloid-beta by microglia through by blocking LRP1, a receptor for amyloid-beta. We found that VacA in HPCFS led to neurodegeneration, evidenced by the presence of phosphorylated tau, phosphorylated alpha-synuclein, synaptic impairment, and neuronal loss. Notably, microglia stimulated with VacA exacerbated neurodegeneration compared to direct HPCFS stimulation. Furthermore, we demonstrated that VacA-mediated neuroinflammation and neurodegeneration were mitigated by LRP1 antagonist or VacA immunodepletion. Conclusions This study demonstrates the efficacy of our human stomach-brain axis model that allows us to untangle the complex association between Helicobacter pylori infection and neurological diseases and discover the mechanism of neurotoxic neuroinflammation systematically and this paves the way for future research and therapeutic interventions. Graphical Abstract