This R01 grant aims to identify new molecular pathways and treatments to prevent mitochondrial-based injury and dopaminergic (DA) neuronal cell death in Parkinson disease (PD). As tools, we will take advantage of the potential interplay of genes mutated in PD and exposure to environmental risk factors, such as certain pesticides, that might contribute to disease in part as mitochondrial toxins. Although several epidemiological studies have suggested an association of pesticides, particularly the combination of paraquat (PQ) and maneb (MB), to the etiology of PD, evidence for a direct role of their effect on human DA neurons remains poorly studied. One reason for this is the inability to effectively model the disease in human cells, in part due to the nature of PD manifestations (i.e., late onset and slow progression of pathology), and in part due to complications arising from epistatic effects of the patient's genetic background that might influence the outcome after exposure. To overcome these problems, we are using a human iPSC model of PD in which the control and mutant cells are genetically identical (isogenic) except for a single pathogenic poin mutation in the -synuclein locus (A53T). This model gives us an unprecedented opportunity to examine the vulnerability of human A9-type DA neurons after pesticide exposure with regard to genetic background. We mount preliminary data that decreased activity of MEF2, a transcription factor involved in both neurogenesis and neuroprotection, may play a contributory role in PD pathogenesis due to environmental or genetic insult. We find that the pesticides PQ, MB, or rotenone affect mitochondrial function in DA neurons, producing excessive nitric oxide (NO) and reactive oxygen species (ROS). NO/ROS lead to aberrant S-nitrosylation/oxidation of MEF2 (forming SNO-MEF2 and SOH-MEF2). These posttranslational modifications impair MEF2 transcriptional activity. We identify potential downstream cellular events resulting from nitrosylation/oxidation of MEF2, including a decrease in the transcriptional co-activator molecule PGC1, whose gene is regulated by MEF2 and is a key regulator of mitochondrial function. We will next attempt to rescue hiPSC-derived neurons from PD-related cell death by (a) preventing nitrosylation/oxidation of MEF2 via genetic modification of MEF2, or (b) boosting PGC1 activity. Finally, in our HTS Center, as potential therapeutics we will identify small molecules tht increase MEF2 activity or prevent its oxidation. Thus, these studies will elucidate molecular events linking genetic and environmental risk factors in PD, and we will use this information to develop novel therapeutic targets for drug screening for the treatment of PD in the human context (by using hiPSC-derived DA neurons).
As Specific Aims we plan:
Aim 1. To characterize environmental risk factor- induced vulnerability in isogenic hiPSC A53T--synuclein vs. WT DA neurons (and vs. non-DA neurons).
Aim 2. To elucidate pathways for this susceptibility involving SNO-MEF2 of SOH-MEF2.
Aim 3. To screen for novel agents that protect from this genetic or environmentally-induced neuronal injury in PD.

Public Health Relevance

Parkinson's disease (PD) is the most common neurodegenerative movement disorder and has no disease- modifying treatment. Here, we generate dopaminergic neurons using isogenic human pluripotent induced stem cells (hiPSCs), meaning that only the single point mutation responsible for causing PD is different between the diseased neurons and the controls. Using this 'disease-in-a-dish' model, we then study pathways to neuronal injury in PD and begin to develop new drug candidate therapies via high-throughput screening (HTS) and medicinal-chemistry efforts in our Institute's extensive NIH (MLPCN)-funded HTS and Drug Development Core Facility.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS086890-02
Application #
8828822
Study Section
Clinical Neuroplasticity and Neurotransmitters Study Section (CNNT)
Program Officer
Sutherland, Margaret L
Project Start
2014-04-01
Project End
2015-06-30
Budget Start
2015-04-01
Budget End
2015-06-30
Support Year
2
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Sanford Burnham Prebys Medical Discovery Institute
Department
Type
DUNS #
020520466
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Connolly, Niamh M C; Theurey, Pierre; Adam-Vizi, Vera et al. (2018) Guidelines on experimental methods to assess mitochondrial dysfunction in cellular models of neurodegenerative diseases. Cell Death Differ 25:542-572
Mann, Aman P; Scodeller, Pablo; Hussain, Sazid et al. (2018) Publisher Correction: Identification of a peptide recognizing cerebrovascular changes in mouse models of Alzheimer's disease. Nat Commun 9:1070
Ryan, Tammy; Bamm, Vladimir V; Stykel, Morgan G et al. (2018) Cardiolipin exposure on the outer mitochondrial membrane modulates ?-synuclein. Nat Commun 9:817
Nagar, Saumya; Noveral, Sarah M; Trudler, Dorit et al. (2017) MEF2D haploinsufficiency downregulates the NRF2 pathway and renders photoreceptors susceptible to light-induced oxidative stress. Proc Natl Acad Sci U S A 114:E4048-E4056
Mann, Aman P; Scodeller, Pablo; Hussain, Sazid et al. (2017) Identification of a peptide recognizing cerebrovascular changes in mouse models of Alzheimer's disease. Nat Commun 8:1403
Tu, Shichun; Akhtar, Mohd Waseem; Escorihuela, Rosa Maria et al. (2017) NitroSynapsin therapy for a mouse MEF2C haploinsufficiency model of human autism. Nat Commun 8:1488
Oh, Chang-Ki; Sultan, Abdullah; Platzer, Joseph et al. (2017) S-Nitrosylation of PINK1 Attenuates PINK1/Parkin-Dependent Mitophagy in hiPSC-Based Parkinson's Disease Models. Cell Rep 21:2171-2182
Satoh, Takumi; Lipton, Stuart (2017) Recent advances in understanding NRF2 as a druggable target: development of pro-electrophilic and non-covalent NRF2 activators to overcome systemic side effects of electrophilic drugs like dimethyl fumarate. F1000Res 6:2138
Nakamura, Tomohiro; Lipton, Stuart A (2017) 'SNO'-Storms Compromise Protein Activity and Mitochondrial Metabolism in Neurodegenerative Disorders. Trends Endocrinol Metab 28:879-892
Chen, Shanyan; Cui, Jiankun; Jiang, Tao et al. (2017) Gelatinase activity imaged by activatable cell-penetrating peptides in cell-based and in vivo models of stroke. J Cereb Blood Flow Metab 37:188-200

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