In the past years, the collective community of microorganisms found in the human gut (the gut microbiome), has emerged as a new important player influencing Parkinson’s Disease (PD). Specifically, the composition of the gut microbiome was shown to differ between PD patients and healthy individuals and these differences correlate with the severity of the symptoms. Understanding the molecular mechanisms by which gut bacteria interact with the host to alter physiology in remote tissues, can lead to novel prognostic and therapeutic interventions for PD. However, how single species of the gut microbiome affect manifestations of the disease remains unclear.
In people with Parkinson’s, the protein alpha-synuclein (α-syn) builds up and forms toxic clumps which induce the degeneration of specific dopamine-producing neurons. Using a worm model of PD expressing the α-syn, we tested the effect of commercially available probiotic bacteria in the formation of toxic protein aggregates. We identified a strongly protective effect when worms were fed the strain Bacillus subtilis PXN21 (isolated from Bio-Kult), in comparison to the regular worm’s diet. The main goal of this project was to study how this probiotic induces the protective effect, at the molecular level. We proposed to elucidate this by focusing on both organisms in the interaction: the bacteria and the worms. We aimed to explore the physiological changes induced by B. subtilis in the worms by studying the overall gene expression in the host. From the bacterial side, we proposed to identify specific genes and metabolic pathways used by B. subtilis to reduce protein aggregates by doing a single-gene deletion library screening.
