The overarching goal of this renewal R01 is to advance our understanding of the biology and pathology of Leucine-Rich Repeat Kinase 2 (LRRK2), whose mutations are the most common genetic cause of Parkinson's disease (PD). LRRK2 encodes a large and complex protein (285kD) including a kinase and a GTPase domain. Previously multiple lines of evidence have led to a gain-of-function hypothesis that LRRK2 pathogenic mutations cause increased kinase activity that is attributable to the neurotoxicity. Recent studies in cell cultures implicate LRRK2 in vesicle trafficking, neurite outgrowth, cytoskeletal dynamics, protein translation and degradation, mitochondria dynamics and inflammatory response. Importantly, the study of genetic animal models show that the pathogenic LRRK2 mutations impair dopamine transmission without causing neurodegeneration, suggesting a pathophysiological role of LRRK2 in neurotransmission at early disease stage prior to neurodegeneration. Emerging evidence has also linked LRRK2 to neuroinflammation that is a contributing factor to neurodegeneration in PD. But the precise mechanisms whereby LRRK2 mutant mediate the neural dysfunction and neurotoxicity remain unclear. Therefore, we hypothesize that (1) LRRK2 regulates SV protein functions and neurotransmission that is impaired by LRRK2 pathogenic mutations; 2) LRRK2 plays a critical role in neuroinflammatory response in glial cells; LRRK2 mutants deregulate glial inflammatory pathway and cause neurotoxicity in PD.
Our specific aims are to (1) determine the pathogenic role of LRRK2 in SV traffic and neurotransmission; (2) examine dysfunctional LRRK2 in glial neuroinflammatory response. A major challenge of LRRK2 research is the lack of well-defined neurodegeneration models of LRRK2 that are relevant to the PD pathogenesis. In fact, the incomplete disease penetrance of the common mutation G2019S suggests a significant contribution of environmental factors to PD pathogenesis.
Our third aim i s then to test the hypothesis in animal models that LRRK2 causes neurodegeneration in PD through genetic lesion and environmental toxin-linked neuroinflammation. Successful completion of the study not only will gain insight into LRRK2 biology and pathophysiology, but also will deliver valuable cell and animal models for interrogating neurodegenerative pathways in PD and developing platforms for LRRK2 inhibitor screening.

Public Health Relevance

Our application will investigate potential pathogenic pathways mediated by LRRK2 in Parkinson's disease. We seek to develop two-hit LRRK2 neurodegeneration model for PD by combining LRRK2 genetic lesions and environmental toxin exposure. If successful, our study not only will gain insight into molecular and cellular mechanism for the pathogenesis of PD, but also will establish valuable cell and animal models for developing therapeutic strategies to treat PD.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS060809-08
Application #
8839309
Study Section
Special Emphasis Panel (ZRG1-MDCN-E (03))
Program Officer
Sieber, Beth-Anne
Project Start
2007-12-01
Project End
2018-04-30
Budget Start
2015-05-01
Budget End
2016-04-30
Support Year
8
Fiscal Year
2015
Total Cost
$456,065
Indirect Cost
$161,166
Name
Icahn School of Medicine at Mount Sinai
Department
Neurology
Type
Schools of Medicine
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
Hui, Ken Y; Fernandez-Hernandez, Heriberto; Hu, Jianzhong et al. (2018) Functional variants in the LRRK2 gene confer shared effects on risk for Crohn's disease and Parkinson's disease. Sci Transl Med 10:
Sheehan, Patricia; Yue, Zhenyu (2018) Deregulation of autophagy and vesicle trafficking in Parkinson's disease. Neurosci Lett :
Pan, Ping-Yue; Li, Xianting; Wang, Jing et al. (2017) Parkinson's Disease-Associated LRRK2 Hyperactive Kinase Mutant Disrupts Synaptic Vesicle Trafficking in Ventral Midbrain Neurons. J Neurosci 37:11366-11376
Sweet, Eric S; Saunier-Rebori, Bernadette; Yue, Zhenyu et al. (2015) The Parkinson's Disease-Associated Mutation LRRK2-G2019S Impairs Synaptic Plasticity in Mouse Hippocampus. J Neurosci 35:11190-5
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Dusonchet, Julien; Li, Hu; Guillily, Maria et al. (2014) A Parkinson's disease gene regulatory network identifies the signaling protein RGS2 as a modulator of LRRK2 activity and neuronal toxicity. Hum Mol Genet 23:4887-905
Pan, Ping-Yue; Yue, Zhenyu (2014) Genetic causes of Parkinson's disease and their links to autophagy regulation. Parkinsonism Relat Disord 20 Suppl 1:S154-7
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Dehay, Benjamin; Martinez-Vicente, Marta; Caldwell, Guy A et al. (2013) Lysosomal impairment in Parkinson's disease. Mov Disord 28:725-32
Yang, Yi; Coleman, Michael; Zhang, Lihui et al. (2013) Autophagy in axonal and dendritic degeneration. Trends Neurosci 36:418-28

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