Characterising α-synuclein in epithelial cells of the gut — The Association Specialists

Characterising α-synuclein in epithelial cells of the gut (21367)

Anastazja M Gorecki 1 2 3 , Chidozie C Anyaegbu 1 4 , Varsha Singh 5 , Kathy A Fuller 6 , Subhash Kulkarni 5 , Ryan S Anderton 3
  1. Curtin Health Innovation Research Institute, Curtin University, Nedlands, Western Australia, Australia
  2. School of Biological Sciences, University of Western Australia, Crawley, Western Australia, Australia
  3. University of Notre Dame, Fremantle, WESTERN AUSTRALIA, Australia
  4. Perron Institute for Neurological and Translational Science, Nedlands, Western Australia, Australia
  5. School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
  6. Translational Cancer Pathology Laboratory, School of Biomedical Sciences , University of Western Australia, Crawley

Pro-inflammatory environmental factors and disruptions to the gut microbiome are recognised contributors to Parkinson’s disease, and exogenous α-synuclein fibrils spread from the gut to brain via the vagus nerve in animal models. However, the natural cause of enteric α-synuclein pathology is unknown, but emerging research implicates enteroendocrine cells in the gut epithelium. We investigated epithelial α-synuclein through confocal microscopy and western blotting of human intestinal epithelial monolayers (Aim 1), and imaging flow cytometry (IFC) of murine enteroendocrine STC-1 cells (Aim 2). Aim 1 demonstrated α-synuclein staining in enteroendocrine cells and goblet cells, the latter being a novel result. Consequently, stimulation of the apical monolayer with faecal proteins revealed a non-significant trend for increased insoluble α-synuclein, suggesting modulation by gut luminal contents. To investigate the targeted effect of a microbial metabolite, STC-1 cells were exposed to lipopolysaccharide (8 and 32 ug/ml for 24 hours), with α-synuclein localisation and phosphorylation assessed through IFC. This enabled the robust quantification of morphological and fluorescent data from large populations of cells, using objective data-processing algorithms to analyse protein expression and localisation at the single-cell level. Interestingly, 8 ug/ml LPS significantly decreased levels and altered intracellular distribution of α-synuclein in a TLR4-dependent manner, and did not cause α-synuclein aggregation or increase phosphorylated α-synuclein, such as that seen in PD. Overall, these findings demonstrate the complex interplay between gut metabolites and α-synuclein in the gut epithelium, providing insights into potential mechanisms contributing to PD.