Project Summary
Synucleinopathies, including dementia with Lewy bodies (DLB) and Parkinson’s disease (PD), are a growing
health crisis, affecting over 1 million people in the United States and an estimated 10 million people globally.
Synucleinopathies are caused by accumulation of the protein a-synuclein (a-syn) into unnatural fibrils in the brain
and can manifest with motor symptoms, cognitive symptoms, or a combination of the two. There are currently
no effective treatments to cure or prevent synucleinopathies, in large part because there is no clear cause for
disease. There are many identified genetic and environmental risk factors associated with synucleinopathies,
but the context in which these factors lead to disease is still unknown. In addition to direct mutations to SNCA,
the gene that encodes a-syn, mutations to GBA and APOE are well established risk factors and have been
shown to increase a-syn aggregation. However, none of these risk factors are great predictors of disease on
their own, suggesting unknown genetic and environmental interactions likely influence the initiation, severity, and
clinical outcomes of a-syn pathology. In this proposal, I focus on how both cell type and genotype interact with
each other to modulate a-syn pathology severity. I hypothesize that a-syn pathology is precipitated by epistatic
interactions between genetic factors that disrupt homeostasis in different cell types and leaves dopaminergic
neurons vulnerable to deleterious a-syn pathology and neurodegeneration. I will investigate this hypothesis using
two independent, complementary approaches to dissect the cellular and molecular mechanisms that modulate
a-syn phenotypes. First, I will couple GBA knockdown with SNCA-triplication, wild-type, and knockout cell lines.
There is a clear link between GBA mutations and a-syn aggregation, but how these proteins connect is still
unknown. I will use high-content imaging with genetically encoded fluorescent markers to quantify lysosomal and
mitochondrial dynamics in live cells. This will reveal how GBA responds to different a-syn dosages and how that
affects cellular homeostasis. Second, I will leverage isogenic lines containing APOE allelic variants and GBA
knockdown. GBA and APOE are involved in lipid metabolism, suggesting a putative link between lipid
metabolism disruption and a-syn pathology, although there is no published connection between the two proteins.
I will use next generation genomic sequencing and proteomic approaches to determine the interacting effects
between SNCA, GBA, and APOE allelic variants on a-syn pathology severity. Completion of this aim will uncover
whether GBA and APOE are acting through converging or independent pathways, expanding our knowledge of
the network that contributes to disease pathology. By coupling multiple genetic risk factors into a multi-cell type
model, I will pioneer new technology and approaches to dissect epistatic mechanisms that influence a-syn
pathology. These insights will guide us in developing new therapeutic approaches, enabling earlier detection,
treatment, and prevention of synucleinopathies.
