Synuclein aggregation in dopaminergic neurons is a hallmark of Parkinson's disease (PD) pathology. The most common genetic risk factor for PD is glucocerebrosidase (GBA) mutation with as many as 7% of PD patients carrying this mutation. Work to date has primarily focused on the loss of GBA enzymatic activity that could contribute to ?-synuclein accumulation and/or aggregation. However, evidence has indicated that improperly folded mutant GBA could also contribute to the ?-synuclein aggregation independent of the loss of enzymatic activity. Our central hypothesis is that mutant GBA is mistargeted from lysosomes to the cytosol, which interferes with ?-synuclein degradation by chaperone-mediated autophagy (CMA). We will test this hypothesis with a combination of biochemical, cell biological, mouse genetics, and neuropath logical techniques in several systems including isolated lysosomes, mouse models, post-mortem human brain, and fibroblasts from patients'skin biopsy. Our research strategies are divided into three specific aims:
Aim 1 will investigate the mechanism by which mutant GBA attenuates CMA and leads to ?-synuclein accumulation by examining each step of CMA in an in vitro system using isolated lysosomes, purified mutant GBA and ?- synuclein proteins.
Aim 2 will study whether CMA alteration occurs in GBA-mutant mouse models by using a novel CMA reporter in neuronal cultures and determine whether the protein levels of CMA machinery components change in GBA-mutant mouse models and post-mortem PD brain with GBA mutations.
Aim 3 will determine CMA activity using the reporter in the skin fibroblasts from PD patients with GBA mutations, PD patients without GBA mutations, and age-matched controls. These data will provide evidence on whether mutant GBA causes CMA dysfunction, leading to ?-synuclein aggregation, and whether CMA dysfunction is a typical feature of PD. The proposed study could contribute to the future identification of mechanism-based biomarker and therapeutic targets. This K08 proposal also outlines a detailed 5-year training program with specific formal coursework and structured mentoring for the candidate, Sheng-Han Kuo, M.D. The proposed work will be carried out in the Department of Neurology at Columbia University, an excellent environment for training physician-scientists. He will receive the necessary training under the mentorship of Drs. David Sulzer, Ana Maria Cuervo, and Karen Marder, world-renowned investigators in the PD field and acquire necessary skill set to become an independent researcher. The long-term goal of the candidate is to be a translational physician-scientist to investigate the mechanism underlying PD pathology and to develop clinical applicable biomarkers for PD.

Public Health Relevance

Parkinson's disease (PD) is the second most common neurodegenerative disorders and currently there is no effective treatment for the underlying neurodegeneration in PD. Understanding the common mechanism of genetic PD pathology could potentially lead to the identification of useful biomarkers and therapies for PD patients

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08NS083738-02
Application #
8686980
Study Section
Neurological Sciences Training Initial Review Group (NST)
Program Officer
Sutherland, Margaret L
Project Start
2013-07-01
Project End
2018-06-30
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
2
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Neurology
Type
Schools of Medicine
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10032
Kuo, Sheng-Han; Wang, Jie; Tate, William J et al. (2016) Cerebellar Pathology in Early Onset and Late Onset Essential Tremor. Cerebellum :
Alcalay, Roy N; Levy, Oren A; Wolf, Pavlina et al. (2016) SCARB2 variants and glucocerebrosidase activity in Parkinson's disease. NPJ Parkinsons Dis 2:
Lo, Raymond Y; Figueroa, Karla P; Pulst, Stefan M et al. (2016) Depression and clinical progression in spinocerebellar ataxias. Parkinsonism Relat Disord 22:87-92
Aranca, Tanya V; Jones, Tracy M; Shaw, Jessica D et al. (2016) Emerging therapies in Friedreich's ataxia. Neurodegener Dis Manag 6:49-65
Louis, Elan D; Rabinowitz, Daniel; Choe, Matthew et al. (2016) Mapping Purkinje Cell Placement Along the Purkinje Cell Layer: an Analysis of Postmortem Tissue from Essential Tremor Patients vs. Controls. Cerebellum 15:726-731
Kuo, Sheng-Han; Lin, Chi-Ying; Wang, Jie et al. (2016) Deep brain stimulation and climbing fiber synaptic pathology in essential tremor. Ann Neurol 80:461-5
Dong, Su-Yan; Guo, Yan-Jie; Feng, Ya et al. (2016) The epigenetic regulation of HIF-1α by SIRT1 in MPP(+) treated SH-SY5Y cells. Biochem Biophys Res Commun 470:453-9
Alcalay, Roy N; Levy, Oren A; Waters, Cheryl C et al. (2015) Glucocerebrosidase activity in Parkinson's disease with and without GBA mutations. Brain 138:2648-58
Lo, Raymond Y; Figueroa, Karla P; Pulst, Stefan M et al. (2015) Vascular risk factors and clinical progression in spinocerebellar ataxias. Tremor Other Hyperkinet Mov (N Y) 5:287
Kuo, Sheng-Han; Louis, Elan D (2015) Studying cerebellar dysfunction in neuropathy-related tremor. Clin Neurophysiol 126:1645-6

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