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.
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
|Louis, Elan D; Kuo, Sheng-Han; Tate, William J et al. (2017) Cerebellar pathology in childhood-onset vs. adult-onset essential tremor. Neurosci Lett 659:69-74|
|Lin, Chi-Ying; Kuo, Sheng-Han (2017) Cerebellar Ataxia and Hearing Impairment. JAMA Neurol 74:243-244|
|Gan, Shi-Rui; Wang, Jie; Figueroa, Karla P et al. (2017) Postural Tremor and Ataxia Progression in Spinocerebellar Ataxias. Tremor Other Hyperkinet Mov (N Y) 7:492|
|Luo, Lan; Wang, Jie; Lo, Raymond Y et al. (2017) The Initial Symptom and Motor Progression in Spinocerebellar Ataxias. Cerebellum 16:615-622|
|Kuo, Sheng-Han; Wang, Jie; Tate, William J et al. (2017) Cerebellar Pathology in Early Onset and Late Onset Essential Tremor. Cerebellum 16:473-482|
|Kuo, Sheng-Han; Lin, Chi-Ying; Wang, Jie et al. (2017) Climbing fiber-Purkinje cell synaptic pathology in tremor and cerebellar degenerative diseases. Acta Neuropathol 133:121-138|
|Wang, Jie; Kelly, Geoffrey C; Tate, William J et al. (2016) Excitatory Amino acid transporter expression in the essential tremor dentate nucleus and cerebellar cortex: A postmortem study. Parkinsonism Relat Disord 32:87-93|
|Alcalay, Roy N; Levy, Oren A; Wolf, Pavlina et al. (2016) SCARB2 variants and glucocerebrosidase activity in Parkinson's disease. NPJ Parkinsons Dis 2:|
|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|
|Kuo, Sheng-Han; Quinzii, Catarina M (2016) Coenzyme Q10 as a Peripheral Biomarker for Multiple System Atrophy. JAMA Neurol 73:917-9|
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