CSF Oligomeric α-synuclein targeted nano scavengers as a Parkinson's disease theranostic - Project Summary The pathogenesis of Parkinson’s disease (PD) and related synucleinopathies such as dementia with Lewy bodies are characterized by progressive deposition Lewy bodies and Lewy neurites composed primarily of phosphorylated alpha- synuclein aggregates (α-syn), neuroinflammation, blood-brain barrier compromise, and neurodegeneration. Currently, there are no clinically approved biomarker diagnostic tools or disease modifying treatments for PD. Clinical diagnosis is based on a combination of motor and nonmotor symptoms, but the neurodegeneration process may precede the first appearance of these symptoms by decades. Empirical data suggests that levels of oligomeric α-syn in the cerebrospinal fluid (CSF) of PD patients surpass those of normal individuals by several orders of magnitude. Oligomeric α-syn and reactive gliosis are strongly implicated in the initiation and spread of the disease. Recent data from clinical trials with anti-amyloid-β (anti-Aβ) monoclonal antibodies (mAbs) in Alzheimer’s disease (AD), (despite lack of clarity in the full safety/efficacy profile), suggest that anti-Aβ mAbs statistically improved cognitive and biomarker outcomes, demonstrating that neurodegenerative amyloidosis disorders can be slowed or halted. Over the past decade, we have demonstrated in several mouse models of neurodegeneration that following tail vein injection, liposomes bearing an imaging contrast payload cross the BBB into the CSF, primarily at the blood-CSF barrier at the at the choroid plexus and cerebrovascular leaks and bind to specific targets within the brain, enabling separation of disease mice from controls using noninvasive magnetic resonance imaging (MRI) or computed tomography imaging. Our lead product is currently in clinical trials as the first MRI-based imaging agents for Aβ plaques in AD. In a recent proposal funded by the NIA (R21 AG067131), we hypothesized that a variant of our agent labeled with oligomeric α-syn ligands will act as a scavenger for the pathologic species resulting in the formation of cross- linked agglomerates of the agent and pathologic species making them more suitable substrates for rapid phagocytosis (sizes > 0.5 microns) by activated glia. This in turn can lead to momentary accumulation of detectable levels of the agent in PD positive brains enabling noninvasive separation of test subjects from controls. Our preliminary data demonstrates successful in vitro formation of agglomerates upon exposure of the agent to α-syn fibrils and accelerated uptake of the ensuing agglomerates by microglia and neuroblastoma cell lines. In vivo administration by tail vein injection followed by MRI showed statistically significant signal enhancement in the brains of transgenic mice versus controls. The in vivo data was verified by ex-vivo immunohistochemical analysis which showed a correlation between in vivo MRI signal, regional distribution of the agent in brain tissue, Lewy pathology, and microglia activity. In this application, we seek to capitalize on this data and our experience in the area to fully establish the preclinical potential of our nano scavenger concept both as diagnostic and therapeutic strategies for PD. Specifically, we propose to test the efficacy of the agent to profile/halt disease progression from the prodromal stage through early to late stages in the M83 α-syn transgenic mouse line. The in vivo data will be validated with ex vivo histology analysis and behavioral studies. Furthermore, we propose to establish more insights on the cellular mechanisms involved in uptake and degradation of the biomarker using both murine and human cell lines.
