Helicobacter pylori-Vacuolating Cytotoxin A Induces Neurotoxic Neuroinflammation in Human Multicellular Models

Several epidemiological studies have suggested a possible link between Helicobacter pylori (HP) infection and neurodegenerative diseases. However, in the current research, the mechanistic basis of this association remains unclear due to the complexity of multiple effects triggered by HP infection. Here, we expose in vitro cellular models to HP’s cell-free supernatant (_HPCFS) and perform liquid chromatography–mass spectrometry and inhibition assays to identify potential neurodegenerative risk factors associated with HP. We first confirm that _HPCFS disrupts the integrity of the gut and brain barriers via vacuolating cytotoxin A (VacA) binding to low-density lipoprotein receptor-related protein-1 (LRP1), reducing ZO-1 tight junction protein levels and transmembrane electrical resistance. In addition, _HPCFS activates central innate immune cells, as evidenced by increased expression of inflammatory markers, elevated oxidative stress, the release of neurotoxic factors from microglia and astrocytes. VacA hinders microglial amyloid-beta phagocytosis by blocking LRP1, a key receptor for amyloid-beta clearance. We observe that _HPCFS induces neurodegeneration, as indicated by the presence of phosphorylated tau, phosphorylated alpha-synuclein, synaptic impairment, and neuronal damage. Notably, microglia stimulated with _HPCFS exacerbate neurodegeneration more than direct _HPCFS exposure to neurons. Furthermore, we demonstrate that neuroinflammation and neurodegeneration mediated by _HPCFS are mitigated by an LRP1 antagonist or VacA immunodepletion. This study reveals a cellular mechanism of neurotoxic inflammation through multicellular interactions, paving the way for future therapeutic interventions in HP infection-associated neurodegeneration.