Submitted Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative and is presently incurable with the underlying molecular cause in most individuals not being clear. In 5-10% of cases, the disease cause can be attributed to mutations in a single gene and hence a clear cellular basis. These genetic forms of PD have implicated mitochondrial, lysosomal and, protein aggregation and trafficking dysfunction in PD. Current PD therapies treat only the symptoms and do not slow disease progression. The major impediment to finding a cure for PD is the lack of robust, symptom-independent biomarkers that accurately reflect disease progression and/or causation in individuals. At Griffith University, Assoc. Prof Wood and his team has developed a novel, innovative cell model of sporadic PD which addresses the unique genetic background of each patient. This model uses primary olfactory neuroepithelial (ONS) cell lines from 60 PD patients and 61 healthy subjects. Using a combination of microscopy-based high content screening and biochemical assays, Wood’s team identified significant PD-specific alterations in ONS cell organelle homeostasis and functions which can be exacerbated by exposure to chemical stresses. This represents a unique opportunity to investigate the role of gene-environment interactions in the progression of PD. Our overarching goal is to identify the molecular triggers of PD within individuals, so that we can best tailor personalised treatments. Our objectives are to: 1. Stratify PD patient cohorts based on the differential response of their cellular organelles to chemical stresses, using high content imaging; 2. Validate stress responses observed in ONS cells in more disease-relevant cell types namely dopaminergic neurons derived from iPS cells. The hypothesis being tested is: “The differential stress responses of PD ONS cells, reflect systemic differences in organelle homeostasis and will be applicable to other cell types and patient cohorts.” – investigation of the role of gene-environment interactions for the predisposition of Parkinson’s disease. The aim of the PD-BIOMARK project is to address specific aspects arising from observations in our novel PD cell model. These are: (i) do chemical stresses induce PD-specific responses in both ONS cells and iPS cell-derived dopaminergic neurons from the same patient/individual? ONS cells will be reprogrammed to iPS cells and then differentiated to dopaminergic neurons. This will establish if ONS cells reflect system differences in organelle homeostasis. (ii) Are the responses of cells from one cohort (GU) to chemical stresses comparable to another cohort (LCSB)? This will provide some indication of the utility of the stresses to identifying and stratifying PD patients. To achieve these objectives, Assoc. Prof Wood will integrate with the LCSB which is world-leading in PD research. The LCSB has also established the generation of iPS cell lines from PD patients. Moreover, the LCSB lab uses the same high content imaging microscopes as the GU group ensuring ease of data transfer and analysis and the comparison of data obtained from ONS cells and iPSC-derived dopaminergic neurons. In conclusion, this collaboration combines a number of unique resources and expertise. The GU team has established that exposure of primary ONS cells to chemical stresses (sourced from samples unique to GU), can identify disease-specific responses in sporadic PD patient-derived cell lines. This cell system facilitates high-content and high-throughput screens. The team at LCSB has world-leading expertise in the derivation, differentiation and analysis of iPS cell lines derived from PD patients. In this proof-of-concept proposal we aim to test if the stress responses of PD patient ONS cells accurately reflect disease triggers in individual patients by assaying iPS cell-derived neurons derived from these same cell lines. This relies on the expertise of the team at LCSB.