Lipopolysaccharide from Gut Microbiota Modulates α-Synuclein Aggregation and Alters Its Biological Function

Area of Science:

• Neuroscience
• Biochemistry
• Microbiology

Background:

• Altered intestinal permeability is linked to Parkinson's disease (PD) pathophysiology in the enteric nervous system, potentially preceding central nervous system (CNS) involvement.
• Gut bacteria-derived lipopolysaccharide (LPS), an inflammatory endotoxin, is implicated in modulating alpha-synuclein (α-synuclein) aggregation, a key process in PD.

Purpose of the Study:

• To investigate the molecular mechanisms underlying the interaction between LPS and α-synuclein.
• To elucidate how this interaction influences α-synuclein nucleation and aggregation pathways.
• To characterize the role of this gut-derived interaction in Parkinson's disease progression.

Main Methods:

• Utilized biophysical techniques and microscopic imaging to observe LPS-α-synuclein molecular interactions.
• Employed Nuclear Magnetic Resonance (NMR) spectroscopy to identify specific residues involved in LPS binding.
• Assessed the impact of LPS-α-synuclein interaction on cellular internalization and cytotoxicity.

Main Results:

• Direct molecular interaction between LPS and α-synuclein was revealed, leading to rapid nucleation events.
• This heteromolecular interaction stabilizes α-helical intermediates in the α-synuclein aggregation pathway.
• NMR studies identified LPS-binding motifs that modulate α-synuclein nucleating forms, influencing cellular uptake and toxicity.

Conclusions:

• The study characterizes a novel heteromolecular interaction between LPS and α-synuclein.
• This interaction represents an alternative pathway contributing to Parkinson's disease pathogenesis, originating in the gut.
• Findings suggest potential therapeutic strategies targeting gut-derived factors in early Parkinson's disease.