- PROJECT 1: BIOLOGY OF PARKIN AND ITS ROLE IN PARKINSON'S DISEASE Parkinson's disease (PD) is a complex neurodegenerative disorder that is both sporadic and familial. Mutations in parkin are the most common cause of autosomal recessive PD. In sporadic PD dopaminergic, oxidative and nitrosative stress as well as c-Abl phosphorylation result in inhibition of parkin. Thus, loss of parkin function is elemental to both familial and sporadic PD. Parkin is an E3 ligase, this loss of function leads to accumulation of the substrates, AIMP2 and PARIS. We have found that AIMP2 expression leads to age dependent DA neurodegeneration due to parthanatos. And PARIS expression may lead to loss of mitochondrial quality control that promotes neurodegeneration. Our hypothesis is that parkin inactivation in sporadic PD by nitrosative/oxidative stress, and c-Abl activation leads to phosphorylation of parkin on Y143 (pY143 parkin) and inactivation followed by the accumulation of parkin substrates, loss of mitochondrial quality control and toxicity. In parallel, ?-synuclein is phosphorylated on Y39 (pY39 ?-synuclein) resulting in aggregation and subsequent toxicity. Since aggregated ?-synuclein can lead to mitochondrial dysfunction it creates a feed forward cycle.
Aim 1 : One of the unifying features of PD is mitochondrial dysfunction.
This aim will explore the inter- relationship of PARIS and mitochondrial dysfunction caused by mutations in parkin. We have shown that PARIS is an important pathophysiologic substrate of parkin in PD that transcriptionally represses PGC-1? a major transcriptional co-activator that regulates mitochondrial biogenesis and mitochondrial oxidant stress responses.
Aim 2 : Inactivation of parkin results in accumulation of both AIMP2 and PARIS. Expression of either AIMP2 or PARIS is sufficient to promote age dependent DA neurodegeneration. The sequence of events activated by PARIS and AIMP2 will be explored to determine if and how these two proteins interact to initiate the cell death program, parthanatos.
Aim 3 : We observe pY143 parkin and elevated AIMP2 and PARIS in A53T ?-synuclein transgenic mice that raises the question of whether parkin inactivation, PARIS and AIMP2 upregulation and PARP1 activation play a role in ?-synuclein induced neurodegeneration? This possibility will be explored with the ?-synuclein preformed fibrils (PFFs) model of PD.
Aim 4 : State-of-the-art technology including deep sequencing and SILAM (stable isotope labeling by amino acids in mammals) will be deployed to identify genes and proteins that are regulated by adult conditional knockout of parkin and their relationship to PARIS induction with the goal of identify nodal points in the signal cascade of neurodegeneration that can provide new targets for the treatment of PD.
Loss of parkin function the most common cause of familial PD and is present in the majority of sporadic PD. Loss of parkin function leads to accumulation of parkin substrates, AIMP2 and PARIS that facilitate age dependent dopaminergic neuronal cell loss, possibly due to impairment of mitochondrial quality control. The goals of this project are to understand mechanistic signaling events that result in neurodegeneration due to loss of parkin function resulting in accumulation of PARIS and AIMP2.
|Mills, Kelly A; Mari, Zoltan; Bakker, Catherine et al. (2016) Gait function and locus coeruleus Lewy body pathology in 51 Parkinson's disease patients. Parkinsonism Relat Disord 33:102-106|
|Mao, Xiaobo; Ou, Michael Tianhao; Karuppagounder, Senthilkumar S et al. (2016) Pathological Î±-synuclein transmission initiated by binding lymphocyte-activation gene 3. Science 353:|
|Geiger, Joshua T; Arthur, Karissa C; Dawson, Ted M et al. (2016) C9orf72 Hexanucleotide Repeat Analysis in Cases with Pathologically Confirmed Dementia with Lewy Bodies. Neurodegener Dis 16:370-2|
|Mata, Ignacio F; Leverenz, James B; Weintraub, Daniel et al. (2016) GBA Variants are associated with a distinct pattern of cognitive deficits in Parkinson's disease. Mov Disord 31:95-102|
|Rosenthal, Liana S; Drake, Daniel; Alcalay, Roy N et al. (2016) The NINDS Parkinson's disease biomarkers program. Mov Disord 31:915-23|
|Jo, Junghyun; Xiao, Yixin; Sun, Alfred Xuyang et al. (2016) Midbrain-like Organoids from Human Pluripotent Stem Cells Contain Functional Dopaminergic and Neuromelanin-Producing Neurons. Cell Stem Cell 19:248-57|
|Karuppagounder, Senthilkumar S; Xiong, Yulan; Lee, Yunjong et al. (2016) LRRK2 G2019S transgenic mice display increased susceptibility to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mediated neurotoxicity. J Chem Neuroanat 76:90-97|
|Davis, Marie Y; Johnson, Catherine O; Leverenz, James B et al. (2016) Association of GBA Mutations and the E326K Polymorphism With Motor and Cognitive Progression in Parkinson Disease. JAMA Neurol 73:1217-1224|
|Nucifora Jr, Frederick C; Nucifora, Leslie G; Ng, Chee-Hoe et al. (2016) Ubiqutination via K27 and K29 chains signals aggregation and neuronal protection of LRRK2 by WSB1. Nat Commun 7:11792|
|Mills, Kelly A; Mari, Zoltan; Pontone, Gregory M et al. (2016) Cognitive impairment in Parkinson's disease: Association between patient-reported and clinically measured outcomes. Parkinsonism Relat Disord 33:107-114|
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