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Parkinson Disease: HELP
Articles by Darren J. Moore
Based on 28 articles published since 2010
(Why 28 articles?)
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Between 2010 and 2020, D. Moore wrote the following 28 articles about Parkinson Disease.
 
+ Citations + Abstracts
Pages: 1 · 2
1 Review Understanding the GTPase Activity of LRRK2: Regulation, Function, and Neurotoxicity. 2017

Nguyen, An Phu Tran / Moore, Darren J. ·Center for Neurodegenerative Science, Van Andel Research Institute, 333 Bostwick Ave NE, Grand Rapids, MI, 49503, USA. · Center for Neurodegenerative Science, Van Andel Research Institute, 333 Bostwick Ave NE, Grand Rapids, MI, 49503, USA. darren.moore@vai.org. ·Adv Neurobiol · Pubmed #28353279.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most frequent cause of Parkinson's disease (PD) with late-onset and autosomal-dominant inheritance. LRRK2 belongs to the ROCO superfamily of proteins, characterized by a Ras-of-complex (Roc) GTPase domain in tandem with a C-terminal-of-Roc (COR) domain. LRRK2 also contains a protein kinase domain adjacent to the Roc-COR tandem domain in addition to multiple repeat domains. Disease-causing familial mutations cluster within the Roc-COR tandem and kinase domains of LRRK2, where they act to either impair GTPase activity or enhance kinase activity. Familial LRRK2 mutations share in common the capacity to induce neuronal toxicity in cultured cells. While the contribution of the frequent G2019S mutation, located within the kinase domain, to kinase activity and neurotoxicity has been extensively investigated, the contribution of GTPase activity has received less attention. The GTPase domain has been shown to play an important role in regulating kinase activity, in dimerization, and in mediating the neurotoxic effects of LRRK2. Accordingly, the GTPase domain has emerged as a potential therapeutic target for inhibiting the pathogenic effects of LRRK2 mutations. Many important mechanisms remain to be elucidated, including how the GTPase cycle of LRRK2 is regulated, whether GTPase effectors exist for LRRK2, and how GTPase activity contributes to the overall functional output of LRRK2. In this review, we discuss the importance of the GTPase domain for LRRK2-linked PD focusing in particular on its regulation, function, and contribution to neurotoxic mechanisms.

2 Review VPS35, the Retromer Complex and Parkinson's Disease. 2017

Williams, Erin T / Chen, Xi / Moore, Darren J. ·Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI, USA. · Van Andel Institute Graduate School, Van Andel Research Institute, Grand Rapids, MI, USA. ·J Parkinsons Dis · Pubmed #28222538.

ABSTRACT: Mutations in the vacuolar protein sorting 35 ortholog (VPS35) gene encoding a core component of the retromer complex, have recently emerged as a new cause of late-onset, autosomal dominant familial Parkinson's disease (PD). A single missense mutation, AspD620Asn (D620N), has so far been unambiguously identified to cause PD in multiple individuals and families worldwide. The exact molecular mechanism(s) by which VPS35 mutations induce progressive neurodegeneration in PD are not yet known. Understanding these mechanisms, as well as the perturbed cellular pathways downstream of mutant VPS35, is important for the development of appropriate therapeutic strategies. In this review, we focus on the current knowledge surrounding VPS35 and its role in PD. We provide a critical discussion of the emerging data regarding the mechanisms underlying mutant VPS35-mediated neurodegeneration gleaned from genetic cell and animal models and highlight recent advances that may provide insight into the interplay between VPS35 and several other PD-linked gene products (i.e. α-synuclein, LRRK2 and parkin) in PD. Present data support a role for perturbed VPS35 and retromer function in the pathogenesis of PD.

3 Review Mechanisms of LRRK2-dependent neurodegeneration: role of enzymatic activity and protein aggregation. 2017

Islam, Md Shariful / Moore, Darren J. ·Center for Neurodegenerative Science, Van Andel Research Institute, 333 Bostwick Ave NE, Grand Rapids, MI, U.S.A. · Center for Neurodegenerative Science, Van Andel Research Institute, 333 Bostwick Ave NE, Grand Rapids, MI, U.S.A. darren.moore@vai.org. ·Biochem Soc Trans · Pubmed #28202670.

ABSTRACT: Mutations in the

4 Review Modeling LRRK2 Pathobiology in Parkinson's Disease: From Yeast to Rodents. 2015

Daniel, Guillaume / Moore, Darren J. ·School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland. ·Curr Top Behav Neurosci · Pubmed #24850078.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2, PARK8) gene represent the most common cause of familial Parkinson's disease (PD) with autosomal dominant inheritance, whereas common variation at the LRRK2 genomic locus influences the risk of developing idiopathic PD. LRRK2 is a member of the ROCO protein family and contains multiple domains, including Ras-of-Complex (ROC) GTPase, kinase, and protein-protein interaction domains. In the last decade, the biochemical characterization of LRRK2 and the development of animal model s have provided important insight into the pathobiology of LRRK2. In this review, we comprehensively describe the different models employed to understand LRRK2-associated PD, including yeast, invertebrates, transgenic and viral-based rodents, and patient-derived induced pluripotent stem cells. We discuss how these models have contributed to understanding LRRK2 pathobiology and the advantages and limitations of each model for exploring aspects of LRRK2-associated PD.

5 Review Contribution of GTPase activity to LRRK2-associated Parkinson disease. 2013

Tsika, Elpida / Moore, Darren J. ·Laboratory of Molecular Neurodegenerative Research; Brain Mind Institute; School of Life Sciences; Ecole Polytechnique Fédérale de Lausanne (EPFL); Lausanne, Switzerland. ·Small GTPases · Pubmed #24025585.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2, PARK8, OMIM 607060) gene represent the most common known cause of hereditary Parkinson's disease (PD) with late-onset and dominant inheritance. LRRK2 protein is composed of multiple domains including two distinct enzymatic domains, a kinase and a Ras-of-complex (Roc) GTPase, connected by a C-terminal-of-Roc (COR) domain, and belongs to the ROCO protein family. Disease-causing mutations located in the kinase domain enhance kinase activity (i.e., G2019S) whereas mutations clustering within the Roc-COR tandem domain impair GTPase activity (i.e., R1441C/G and Y1699C). Familial LRRK2 mutations commonly induce neuronal toxicity that, at least for the frequent G2019S variant, is dependent on kinase activity. The contribution of GTPase activity to LRRK2-dependent neuronal toxicity is not yet clear. Therefore, both GTPase and kinase activity may be important for mediating neurodegeneration in PD due to familial LRRK2 mutations. At present, the physiological function of LRRK2 in the mammalian brain and the regulation of its enzymatic activity are incompletely understood. In this review, we focus on the GTPase domain of LRRK2 and discuss the recent advances in elucidating its function and its interplay with the kinase domain for the regulation of LRRK2 activity and toxicity. GTPase activity is an important feature of LRRK2 biology and pathophysiology and represents an underexplored yet potentially tractable therapeutic target for treating LRRK2-associated PD.

6 Review Mitochondrial dysfunction in genetic animal models of Parkinson's disease. 2012

Trancikova, Alzbeta / Tsika, Elpida / Moore, Darren J. ·Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. ·Antioxid Redox Signal · Pubmed #21848447.

ABSTRACT: SIGNIFICANCE: Increasing evidence supports a role for abnormal mitochondrial function in the molecular pathophysiology of Parkinson's disease (PD). For three decades we have known that mitochondrial toxins are capable of producing clinical parkinsonism in humans. PD is the most common neurodegenerative movement disorder that is characterized by the progressive loss of substantia nigra dopaminergic neurons leading to a deficiency of striatal dopamine. Although the neuropathology underlying the disease is well defined, it remains unclear why nigral dopaminergic neurons degenerate and die. RECENT ADVANCES: Most PD cases are idiopathic, but there are rare familial cases. Mutations in five genes are known to unambiguously cause monogenic familial PD: α-synuclein, parkin, DJ-1, PTEN-induced kinase 1 (PINK1), and leucine-rich repeat kinase 2 (LRRK2). These key molecular players are proteins of seemingly diverse function, but with potentially important roles in mitochondrial maintenance and function. Cell and animal-based genetic models have provided indispensable tools for understanding the molecular basis of PD, and have provided additional evidence implicating mitochondrial dysfunction as a primary pathogenic pathway leading to the demise of dopaminergic neurons in PD. CRITICAL ISSUES: Here, we critically discuss the evidence for mitochondrial dysfunction in genetic animal models of PD, and evaluate whether abnormal mitochondrial function represents a cause or consequence of disease pathogenesis. FUTURE DIRECTIONS: Mitochondria may represent a potential target for the development of disease-modifying therapies.

7 Article Time course and magnitude of alpha-synuclein inclusion formation and nigrostriatal degeneration in the rat model of synucleinopathy triggered by intrastriatal α-synuclein preformed fibrils. 2019

Patterson, Joseph R / Duffy, Megan F / Kemp, Christopher J / Howe, Jacob W / Collier, Timothy J / Stoll, Anna C / Miller, Kathryn M / Patel, Pooja / Levine, Nathan / Moore, Darren J / Luk, Kelvin C / Fleming, Sheila M / Kanaan, Nicholas M / Paumier, Katrina L / El-Agnaf, Omar M A / Sortwell, Caryl E. ·Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, USA. Electronic address: Joseph.Patterson@hc.msu.edu. · Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, USA; Neuroscience Program, Michigan State University, East Lansing, MI, USA. · Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, USA. · Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, USA; Neuroscience Program, Michigan State University, East Lansing, MI, USA; Mercy Health Hauenstein Neuroscience Medical Center, Grand Rapids, MI, USA. · Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, USA; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA. · Center of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI, USA. · Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA. · College of Pharmacy, Northeast Ohio Medical University, Rootstown, OH, USA. · Neurological Disorders Researcher Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar. ·Neurobiol Dis · Pubmed #31276792.

ABSTRACT: Animal models that accurately recapitulate the accumulation of alpha-synuclein (α-syn) inclusions, progressive neurodegeneration of the nigrostriatal system and motor deficits can be useful tools for Parkinson's disease (PD) research. The preformed fibril (PFF) synucleinopathy model in rodents generally displays these PD-relevant features, however, the magnitude and predictability of these events is far from established. We therefore sought to optimize the magnitude of α-syn accumulation and nigrostriatal degeneration, and to understand the time course of both. Rats were injected unilaterally with different quantities of α-syn PFFs (8 or 16 μg of total protein) into striatal sites selected to concentrate α-syn inclusion formation in the substantia nigra pars compacta (SNpc). Rats displayed an α-syn PFF quantity-dependent increase in the magnitude of ipsilateral SNpc inclusion formation at 2 months and bilateral loss of nigral dopamine neurons at 6 months. Unilateral 16 μg PFF injection also resulted in modest sensorimotor deficits in forelimb adjusting steps associated with degeneration at 6 months. Bilateral injection of 16 μg α-syn PFFs resulted in symmetric bilateral degeneration equivalent to the ipsilateral nigral degeneration observed following unilateral 16 μg PFF injection (~50% loss). Bilateral PFF injections additionally resulted in alterations in several gait analysis parameters. These α-syn PFF parameters can be applied to generate a reproducible synucleinopathy model in rats with which to study pathogenic mechanisms and vet potential disease-modifying therapies.

8 Article Pathogenic alpha-synuclein aggregates preferentially bind to mitochondria and affect cellular respiration. 2019

Wang, Xinhe / Becker, Katelyn / Levine, Nathan / Zhang, Michelle / Lieberman, Andrew P / Moore, Darren J / Ma, Jiyan. ·Center for Neurodegenerative Science, Van Andel Research Institute, 333 Bostwick Avenue N.E, Grand Rapids, MI, 49503, USA. · Department of Pathology, University of Michigan Medical School, Ann Arbor, MI48109, USA. · Center for Neurodegenerative Science, Van Andel Research Institute, 333 Bostwick Avenue N.E, Grand Rapids, MI, 49503, USA. Jiyan.Ma@vai.org. ·Acta Neuropathol Commun · Pubmed #30871620.

ABSTRACT: Misfolded alpha-synuclein (αSyn) is a major constituent of Lewy bodies and Lewy neurites, which are pathological hallmarks of Parkinson's disease (PD). The contribution of αSyn to PD is well established, but the detailed mechanism remains obscure. Using a model in which αSyn aggregation in primary neurons was seeded by exogenously added, preformed αSyn amyloid fibrils (PFF), we found that a majority of pathogenic αSyn (indicated by serine 129 phosphorylated αSyn, ps-αSyn) was membrane-bound and associated with mitochondria. In contrast, only a minuscule amount of physiological αSyn was mitochondrial bound. In vitro, αSyn PFF displayed a stronger binding to purified mitochondria than did αSyn monomer, revealing a preferential mitochondria binding by aggregated αSyn. This selective mitochondrial ps-αSyn accumulation was confirmed in other neuronal and animal αSyn aggregation models that do not require exogenously added PFF and, more importantly, in postmortem brain tissues of patients suffering from PD and other neurodegenerative diseases with αSyn aggregation (α-synucleinopathies). We also showed that the mitochondrial ps-αSyn accumulation was accompanied by defects in cellular respiration in primary neurons, suggesting a link to mitochondrial dysfunction. Together, our results show that, contrary to physiological αSyn, pathogenic αSyn aggregates preferentially bind to mitochondria, indicating mitochondrial dysfunction as the common downstream mechanism for α-synucleinopathies. Our findings suggest a plausible model explaining the formation and the peculiar morphology of Lewy body and reveal that disrupting the interaction between ps-αSyn and the mitochondria is a therapeutic target for α-synucleinopathies.

9 Article Parkinson's disease-linked 2019

Chen, Xi / Kordich, Jennifer K / Williams, Erin T / Levine, Nathan / Cole-Strauss, Allyson / Marshall, Lee / Labrie, Viviane / Ma, Jiyan / Lipton, Jack W / Moore, Darren J. ·Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503. · Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI 49503. · Division of Psychiatry and Behavioral Medicine, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503. · Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503; Darren.Moore@vai.org. ·Proc Natl Acad Sci U S A · Pubmed #30842285.

ABSTRACT: Mutations in the

10 Article Parkin mediates the ubiquitination of VPS35 and modulates retromer-dependent endosomal sorting. 2018

Williams, Erin T / Glauser, Liliane / Tsika, Elpida / Jiang, Haisong / Islam, Shariful / Moore, Darren J. ·Van Andel Institute Graduate School, Van Andel Research Institute, Grand Rapids, MI, USA. · Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI, USA. · Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland. · AC Immune SA, EPFL Innovation Park, Lausanne, Switzerland. · Institute for Cell Engineering and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA. ·Hum Mol Genet · Pubmed #29893854.

ABSTRACT: Mutations in a number of genes cause familial forms of Parkinson's disease (PD), including mutations in the vacuolar protein sorting 35 ortholog (VPS35) and parkin genes. In this study, we identify a novel functional interaction between parkin and VPS35. We demonstrate that parkin interacts with and robustly ubiquitinates VPS35 in human neural cells. Familial parkin mutations are impaired in their ability to ubiquitinate VPS35. Parkin mediates the attachment of an atypical poly-ubiquitin chain to VPS35 with three lysine residues identified within the C-terminal region of VPS35 that are covalently modified by ubiquitin. Notably, parkin-mediated VPS35 ubiquitination does not promote the proteasomal degradation of VPS35. Furthermore, parkin does not influence the steady-state levels or turnover of VPS35 in neural cells and VPS35 levels are normal in the brains of parkin knockout mice. These data suggest that ubiquitination of VPS35 by parkin may instead serve a non-degradative cellular function potentially by regulating retromer-dependent sorting. Accordingly, we find that components of the retromer-associated WASH complex are markedly decreased in the brain of parkin knockout mice, suggesting that parkin may modulate WASH complex-dependent retromer sorting. Parkin gene silencing in primary cortical neurons selectively disrupts the vesicular sorting of the autophagy receptor ATG9A, a WASH-dependent retromer cargo. Parkin is not required for dopaminergic neurodegeneration induced by the expression of PD-linked D620N VPS35 in mice, consistent with VPS35 being located downstream of parkin function. Our data reveal a novel functional interaction of parkin with VPS35 that may be important for retromer-mediated endosomal sorting and PD.

11 Article G2019S LRRK2 enhances the neuronal transmission of tau in the mouse brain. 2018

Nguyen, An Phu Tran / Daniel, Guillaume / Valdés, Pamela / Islam, Md Shariful / Schneider, Bernard L / Moore, Darren J. ·Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA. · Laboratory of Molecular Neurodegenerative Research. · Neurodegenerative Disease Laboratory, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. ·Hum Mol Genet · Pubmed #29088368.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause late-onset, autosomal dominant Parkinson's disease (PD). LRRK2 mutations typically give rise to Lewy pathology in the brains of PD subjects yet can induce tau-positive neuropathology in some cases. The pathological interaction between LRRK2 and tau remains poorly defined. To explore this interaction in vivo, we crossed a well-characterized human P301S-tau transgenic mouse model of tauopathy with human G2019S-LRRK2 transgenic mice or LRRK2 knockout (KO) mice. We find that endogenous or pathogenic LRRK2 expression has minimal effects on the steady-state levels, solubility and abnormal phosphorylation of human P301S-tau throughout the mouse brain. We next developed a new model of tauopathy by delivering AAV2/6 vectors expressing human P301S-tau to the hippocampal CA1 region of G2019S-LRRK2 transgenic or LRRK2 KO mice. P301S-tau expression induces hippocampal tau pathology and marked degeneration of CA1 pyramidal neurons in mice, however, this occurs independently of endogenous or pathogenic LRRK2 expression. We further developed new AAV2/6 vectors co-expressing human WT-tau and GFP to monitor the neuron-to-neuron transmission of tau within defined hippocampal neuronal circuits. While endogenous LRRK2 is not required for tau transmission, we find that G2019S-LRRK2 markedly enhances the neuron-to-neuron transmission of tau in mice. Our data suggest that mutant tau-induced neuropathology occurs independently of LRRK2 expression in two mouse models of tauopathy but identifies a novel pathogenic role for G2019S-LRRK2 in promoting the neuronal transmission of WT-tau protein. These findings may have important implications for understanding the development of tau neuropathology in LRRK2-linked PD brains.

12 Article Human R1441C LRRK2 regulates the synaptic vesicle proteome and phosphoproteome in a Drosophila model of Parkinson's disease. 2016

Islam, Md Shariful / Nolte, Hendrik / Jacob, Wright / Ziegler, Anna B / Pütz, Stefanie / Grosjean, Yael / Szczepanowska, Karolina / Trifunovic, Aleksandra / Braun, Thomas / Heumann, Hermann / Heumann, Rolf / Hovemann, Bernhard / Moore, Darren J / Krüger, Marcus. ·Silantes GmbH, Munich, Germany. · Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany. · Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, USA. · Biochemistry II, Molecular Neurobiochemistry Faculty for Chemistry and Biochemistry Ruhr-University Bochum, NC 7/174 Universitaetsstraße 150, 44780 Bochum, Germany. · CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France. · INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France. · Université de Bourgogne Franche-Comté, UMR Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France. · Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, D-50931 Cologne, Germany. · Center for Molecular Medicine (CMMC), University of Cologne, Germany. · Max Planck Institute for Heart and Lung Research, Ludwigstr. 43, 61231 Bad Nauheim, Germany. ·Hum Mol Genet · Pubmed #27794539.

ABSTRACT: Mutations in leucine-rich repeat kinase 2 (LRRK2) cause late-onset, autosomal dominant familial Parkinson`s disease (PD) and variation at the LRRK2 locus contributes to the risk for idiopathic PD. LRRK2 can function as a protein kinase and mutations lead to increased kinase activity. To elucidate the pathophysiological mechanism of the R1441C mutation in the GTPase domain of LRRK2, we expressed human wild-type or R1441C LRRK2 in dopaminergic neurons of Drosophila and observe reduced locomotor activity, impaired survival and an age-dependent degeneration of dopaminergic neurons thereby creating a new PD-like model. To explore the function of LRRK2 variants in vivo, we performed mass spectrometry and quantified 3,616 proteins in the fly brain. We identify several differentially-expressed cytoskeletal, mitochondrial and synaptic vesicle proteins (SV), including synaptotagmin-1, syntaxin-1A and Rab3, in the brain of this LRRK2 fly model. In addition, a global phosphoproteome analysis reveals the enhanced phosphorylation of several SV proteins, including synaptojanin-1 (pThr1131) and the microtubule-associated protein futsch (pSer4106) in the brain of R1441C hLRRK2 flies. The direct phosphorylation of human synaptojanin-1 by R1441C hLRRK2 could further be confirmed by in vitro kinase assays. A protein-protein interaction screen in the fly brain confirms that LRRK2 robustly interacts with numerous SV proteins, including synaptojanin-1 and EndophilinA. Our proteomic, phosphoproteomic and interactome study in the Drosophila brain provides a systematic analyses of R1441C hLRRK2-induced pathobiological mechanisms in this model. We demonstrate for the first time that the R1441C mutation located within the LRRK2 GTPase domain induces the enhanced phosphorylation of SV proteins in the brain.

13 Article Ubiqutination via K27 and K29 chains signals aggregation and neuronal protection of LRRK2 by WSB1. 2016

Nucifora, Frederick C / Nucifora, Leslie G / Ng, Chee-Hoe / Arbez, Nicolas / Guo, Yajuan / Roby, Elaine / Shani, Vered / Engelender, Simone / Wei, Dong / Wang, Xiao-Fang / Li, Tianxia / Moore, Darren J / Pletnikova, Olga / Troncoso, Juan C / Sawa, Akira / Dawson, Ted M / Smith, Wanli / Lim, Kah-Leong / Ross, Christopher A. ·Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA. · Danone Nutricia Research, 30 Biopolis Street, Matrix Building, #05-01B, Singapore 138671, Singapore. · Department of Molecular Pharmacology, Rappaport Institute of Medical Research, Technion-Israel Institute of Technology, Haifa 31096, Israel. · Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, USA. · Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA. · Division of Neuropathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21201, USA. · Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21201, USA. · Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21201, USA. · Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21201, USA. · Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21201, USA. · Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana 70130-2685, USA. · Neuroscience and Behavioral Disorders Program, Duke-National University of Singapore Graduate Medical School, Singapore 169857, Singapore. · Department of Physiology, National University of Singapore, Singapore 117543, Singapore. ·Nat Commun · Pubmed #27273569.

ABSTRACT: A common genetic form of Parkinson's disease (PD) is caused by mutations in LRRK2. We identify WSB1 as a LRRK2 interacting protein. WSB1 ubiquitinates LRRK2 through K27 and K29 linkage chains, leading to LRRK2 aggregation and neuronal protection in primary neurons and a Drosophila model of G2019S LRRK2. Knocking down endogenous WSB1 exacerbates mutant LRRK2 neuronal toxicity in neurons and the Drosophila model, indicating a role for endogenous WSB1 in modulating LRRK2 cell toxicity. WSB1 is in Lewy bodies in human PD post-mortem tissue. These data demonstrate a role for WSB1 in mutant LRRK2 pathogenesis, and suggest involvement in Lewy body pathology in sporadic PD. Our data indicate a role in PD for ubiquitin K27 and K29 linkages, and suggest that ubiquitination may be a signal for aggregation and neuronal protection in PD, which may be relevant for other neurodegenerative disorders. Finally, our study identifies a novel therapeutic target for PD.

14 Article Adenoviral-mediated expression of G2019S LRRK2 induces striatal pathology in a kinase-dependent manner in a rat model of Parkinson's disease. 2015

Tsika, Elpida / Nguyen, An Phu Tran / Dusonchet, Julien / Colin, Philippe / Schneider, Bernard L / Moore, Darren J. ·Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. · Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA. · Neurodegenerative Studies Laboratory, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. · Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA. Electronic address: Darren.Moore@vai.org. ·Neurobiol Dis · Pubmed #25731749.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause late-onset, autosomal dominant Parkinson's disease (PD). LRRK2 contains functional GTPase and kinase domains. The most common G2019S mutation enhances the kinase activity of LRRK2 in vitro whereas G2019S LRRK2 expression in cultured neurons induces toxicity in a kinase-dependent manner. These observations suggest a potential role for kinase activity in LRRK2-associated PD. We have recently developed a novel rodent model of PD with progressive neurodegeneration induced by the adenoviral-mediated expression of G2019S LRRK2. In the present study, we further characterize this LRRK2 model and determine the contribution of kinase activity to LRRK2-mediated neurodegeneration. Recombinant human adenoviral vectors were employed to deliver human wild-type, G2019S or kinase-inactive G2019S/D1994N LRRK2 to the rat striatum. LRRK2-dependent pathology was assessed in the striatum, a region where LRRK2 protein is normally enriched in the mammalian brain. Human LRRK2 variants are robustly expressed throughout the rat striatum. Expression of G2019S LRRK2 selectively induces the accumulation of neuronal ubiquitin-positive inclusions accompanied by neurite degeneration and the altered distribution of axonal phosphorylated neurofilaments. Importantly, the introduction of a kinase-inactive mutation (G2019S/D1994N) completely ameliorates the pathological effects of G2019S LRRK2 in the striatum supporting a kinase activity-dependent mechanism for this PD-associated mutation. Collectively, our study further elucidates the pathological effects of the G2019S mutation in the mammalian brain and supports the development of kinase inhibitors as a potential therapeutic approach for treating LRRK2-associated PD. This adenoviral rodent model provides an important tool for elucidating the molecular basis of LRRK2-mediated neurodegeneration.

15 Article Conditional expression of Parkinson's disease-related R1441C LRRK2 in midbrain dopaminergic neurons of mice causes nuclear abnormalities without neurodegeneration. 2014

Tsika, Elpida / Kannan, Meghna / Foo, Caroline Shi-Yan / Dikeman, Dustin / Glauser, Liliane / Gellhaar, Sandra / Galter, Dagmar / Knott, Graham W / Dawson, Ted M / Dawson, Valina L / Moore, Darren J. ·Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. · Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. · Department of Neuroscience, Karolinska Institute, Stockholm, Sweden. · Centre of Interdisciplinary Electron Microscopy, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. · Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Adrienne Helis Malvin Medical Research Foundation, New Orleans, LA 70130-2685, USA. · Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA. Electronic address: Darren.Moore@vai.org. ·Neurobiol Dis · Pubmed #25174890.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause late-onset, autosomal dominant Parkinson's disease (PD). The clinical and neurochemical features of LRRK2-linked PD are similar to idiopathic disease although neuropathology is somewhat heterogeneous. Dominant mutations in LRRK2 precipitate neurodegeneration through a toxic gain-of-function mechanism which can be modeled in transgenic mice overexpressing human LRRK2 variants. A number of LRRK2 transgenic mouse models have been developed that display abnormalities in dopaminergic neurotransmission and alterations in tau metabolism yet without consistently inducing dopaminergic neurodegeneration. To directly explore the impact of mutant LRRK2 on the nigrostriatal dopaminergic pathway, we developed conditional transgenic mice that selectively express human R1441C LRRK2 in dopaminergic neurons from the endogenous murine ROSA26 promoter. The expression of R1441C LRRK2 does not induce the degeneration of substantia nigra dopaminergic neurons or striatal dopamine deficits in mice up to 2years of age, and fails to precipitate abnormal protein inclusions containing alpha-synuclein, tau, ubiquitin or autophagy markers (LC3 and p62). Furthermore, mice expressing R1441C LRRK2 exhibit normal motor activity and olfactory function with increasing age. Intriguingly, the expression of R1441C LRRK2 induces age-dependent abnormalities of the nuclear envelope in nigral dopaminergic neurons including reduced nuclear circularity and increased invaginations of the nuclear envelope. In addition, R1441C LRRK2 mice display increased neurite complexity of cultured midbrain dopaminergic neurons. Collectively, these novel R1441C LRRK2 conditional transgenic mice reveal altered dopaminergic neuronal morphology with advancing age, and provide a useful tool for exploring the pathogenic mechanisms underlying the R1441C LRRK2 mutation in PD.

16 Article A Parkinson's disease gene regulatory network identifies the signaling protein RGS2 as a modulator of LRRK2 activity and neuronal toxicity. 2014

Dusonchet, Julien / Li, Hu / Guillily, Maria / Liu, Min / Stafa, Klodjan / Derada Troletti, Claudio / Boon, Joon Y / Saha, Shamol / Glauser, Liliane / Mamais, Adamantios / Citro, Allison / Youmans, Katherine L / Liu, LiQun / Schneider, Bernard L / Aebischer, Patrick / Yue, Zhenyu / Bandopadhyay, Rina / Glicksman, Marcie A / Moore, Darren J / Collins, James J / Wolozin, Benjamin. ·Department of Pharmacology and Experimental Therapeutics and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02215, USA, Howard Hughes Medical Institute, Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, Boston, MA 02215, USA. · Center for Individualized Medicine, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. · Department of Pharmacology and Experimental Therapeutics and. · Laboratory for Drug Discovery in Neurodegeneration, Harvard NeuroDiscovery Center, Brigham and Women's Hospital, Cambridge, MA 02139, USA. · Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland. · Reta Lila Weston Institute of Neurological Studies, UCL, Institute of Neurology, London, WC1N 1PJ, UK. · Neurodegenerative Studies Laboratory, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. · Department of Neurology and Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA. · Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02215, USA, Howard Hughes Medical Institute, Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, Boston, MA 02215, USA, bwolozin@bu.edu jcollins@bu.edu. · Department of Pharmacology and Experimental Therapeutics and Department of Neurology, Boston University School of Medicine, Boston, MA, 02118, USA, bwolozin@bu.edu jcollins@bu.edu. ·Hum Mol Genet · Pubmed #24794857.

ABSTRACT: Mutations in LRRK2 are one of the primary genetic causes of Parkinson's disease (PD). LRRK2 contains a kinase and a GTPase domain, and familial PD mutations affect both enzymatic activities. However, the signaling mechanisms regulating LRRK2 and the pathogenic effects of familial mutations remain unknown. Identifying the signaling proteins that regulate LRRK2 function and toxicity remains a critical goal for the development of effective therapeutic strategies. In this study, we apply systems biology tools to human PD brain and blood transcriptomes to reverse-engineer a LRRK2-centered gene regulatory network. This network identifies several putative master regulators of LRRK2 function. In particular, the signaling gene RGS2, which encodes for a GTPase-activating protein (GAP), is a key regulatory hub connecting the familial PD-associated genes DJ-1 and PINK1 with LRRK2 in the network. RGS2 expression levels are reduced in the striata of LRRK2 and sporadic PD patients. We identify RGS2 as a novel interacting partner of LRRK2 in vivo. RGS2 regulates both the GTPase and kinase activities of LRRK2. We show in mammalian neurons that RGS2 regulates LRRK2 function in the control of neuronal process length. RGS2 is also protective against neuronal toxicity of the most prevalent mutation in LRRK2, G2019S. We find that RGS2 regulates LRRK2 function and neuronal toxicity through its effects on kinase activity and independently of GTPase activity, which reveals a novel mode of action for GAP proteins. This work identifies RGS2 as a promising target for interfering with neurodegeneration due to LRRK2 mutations in PD patients.

17 Article Parkinson's disease-linked mutations in VPS35 induce dopaminergic neurodegeneration. 2014

Tsika, Elpida / Glauser, Liliane / Moser, Roger / Fiser, Aris / Daniel, Guillaume / Sheerin, Una-Marie / Lees, Andrew / Troncoso, Juan C / Lewis, Patrick A / Bandopadhyay, Rina / Schneider, Bernard L / Moore, Darren J. ·Laboratory of Molecular Neurodegenerative Research. · Department of Molecular Neuroscience. · Queen Square Brain Bank for Neurological Disorders, University College London Institute of Neurology, London WC1N 3BG, UK. · Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. · Department of Molecular Neuroscience School of Pharmacy, University of Reading, Reading RG6 6AP, UK. · Reta Lila Weston Institute of Neurological Studies, University College London Institute of Neurology, London WC1N 1PJ, UK. · Neurodegenerative Disease Laboratory, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. · Laboratory of Molecular Neurodegenerative Research Center for Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, USA darren.moore@vai.org. ·Hum Mol Genet · Pubmed #24740878.

ABSTRACT: Mutations in the vacuolar protein sorting 35 homolog (VPS35) gene at the PARK17 locus, encoding a key component of the retromer complex, were recently identified as a new cause of late-onset, autosomal dominant Parkinson's disease (PD). Here we explore the pathogenic consequences of PD-associated mutations in VPS35 using a number of model systems. VPS35 exhibits a broad neuronal distribution throughout the rodent brain, including within the nigrostriatal dopaminergic pathway. In the human brain, VPS35 protein levels and distribution are similar in tissues from control and PD subjects, and VPS35 is not associated with Lewy body pathology. The common D620N missense mutation in VPS35 does not compromise its protein stability or localization to endosomal and lysosomal vesicles, or the vesicular sorting of the retromer cargo, sortilin, SorLA and cation-independent mannose 6-phosphate receptor, in rodent primary neurons or patient-derived human fibroblasts. In yeast we show that PD-linked VPS35 mutations are functional and can normally complement VPS35 null phenotypes suggesting that they do not result in a loss-of-function. In rat primary cortical cultures the overexpression of human VPS35 induces neuronal cell death and increases neuronal vulnerability to PD-relevant cellular stress. In a novel viral-mediated gene transfer rat model, the expression of D620N VPS35 induces the marked degeneration of substantia nigra dopaminergic neurons and axonal pathology, a cardinal pathological hallmark of PD. Collectively, these studies establish that dominant VPS35 mutations lead to neurodegeneration in PD consistent with a gain-of-function mechanism, and support a key role for VPS35 in the development of PD.

18 Article Functional interaction of Parkinson's disease-associated LRRK2 with members of the dynamin GTPase superfamily. 2014

Stafa, Klodjan / Tsika, Elpida / Moser, Roger / Musso, Alessandra / Glauser, Liliane / Jones, Amy / Biskup, Saskia / Xiong, Yulan / Bandopadhyay, Rina / Dawson, Valina L / Dawson, Ted M / Moore, Darren J. ·Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland. ·Hum Mol Genet · Pubmed #24282027.

ABSTRACT: Mutations in LRRK2 cause autosomal dominant Parkinson's disease (PD). LRRK2 encodes a multi-domain protein containing GTPase and kinase domains, and putative protein-protein interaction domains. Familial PD mutations alter the GTPase and kinase activity of LRRK2 in vitro. LRRK2 is suggested to regulate a number of cellular pathways although the underlying mechanisms are poorly understood. To explore such mechanisms, it has proved informative to identify LRRK2-interacting proteins, some of which serve as LRRK2 kinase substrates. Here, we identify common interactions of LRRK2 with members of the dynamin GTPase superfamily. LRRK2 interacts with dynamin 1-3 that mediate membrane scission in clathrin-mediated endocytosis and with dynamin-related proteins that mediate mitochondrial fission (Drp1) and fusion (mitofusins and OPA1). LRRK2 partially co-localizes with endosomal dynamin-1 or with mitofusins and OPA1 at mitochondrial membranes. The subcellular distribution and oligomeric complexes of dynamin GTPases are not altered by modulating LRRK2 in mouse brain, whereas mature OPA1 levels are reduced in G2019S PD brains. LRRK2 enhances mitofusin-1 GTP binding, whereas dynamin-1 and OPA1 serve as modest substrates of LRRK2-mediated phosphorylation in vitro. While dynamin GTPase orthologs are not required for LRRK2-induced toxicity in yeast, LRRK2 functionally interacts with dynamin-1 and mitofusin-1 in cultured neurons. LRRK2 attenuates neurite shortening induced by dynamin-1 by reducing its levels, whereas LRRK2 rescues impaired neurite outgrowth induced by mitofusin-1 potentially by reversing excessive mitochondrial fusion. Our study elucidates novel functional interactions of LRRK2 with dynamin-superfamily GTPases that implicate LRRK2 in the regulation of membrane dynamics important for endocytosis and mitochondrial morphology.

19 Article Divergent α-synuclein solubility and aggregation properties in G2019S LRRK2 Parkinson's disease brains with Lewy Body pathology compared to idiopathic cases. 2013

Mamais, Adamantios / Raja, Meera / Manzoni, Claudia / Dihanich, Sybille / Lees, Andrew / Moore, Darren / Lewis, Patrick A / Bandopadhyay, Rina. ·Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, UK. ·Neurobiol Dis · Pubmed #23747310.

ABSTRACT: Mutations in LRRK2 are the most common genetic cause of Parkinson's disease (PD). The most prevalent LRRK2 mutation is the G2019S coding change, located in the kinase domain of this complex multi-domain protein. The majority of G2019S autopsy cases feature typical Lewy Body pathology with a clinical phenotype almost indistinguishable from idiopathic PD (iPD). Here we have investigated the biochemical characteristics of α-synuclein in G2019S LRRK2 PD post-mortem material, in comparison to pathology-matched iPD. Immunohistochemistry with pS129 α-synuclein antibody showed that the medulla is heavily affected with pathology in G2019S PD whilst the basal ganglia (BG), limbic and frontal cortical regions demonstrated comparable pathology scores between G2019S PD and iPD. Significantly lower levels of the highly aggregated α-synuclein species in urea-SDS fractions were observed in G2019S cases compared to iPD in the BG and limbic cortex. Our data, albeit from a small number of cases, highlight a difference in the biochemical properties of aggregated α-synuclein in G2019S linked PD compared to iPD, despite a similar histopathological presentation. This divergence in solubility is most notable in the basal ganglia, a region that is affected preclinically and is damaged before overt dopaminergic cell death.

20 Article Differential diagnosis of normal pressure hydrocephalus by MRI mean diffusivity histogram analysis. 2013

Ivkovic, M / Liu, B / Ahmed, F / Moore, D / Huang, C / Raj, A / Kovanlikaya, I / Heier, L / Relkin, N. ·Weill Cornell Medical College, New York, NY 10021, USA. ·AJNR Am J Neuroradiol · Pubmed #23257611.

ABSTRACT: BACKGROUND AND PURPOSE: Accurate diagnosis of normal pressure hydrocephalus is challenging because the clinical symptoms and radiographic appearance of NPH often overlap those of other conditions, including age-related neurodegenerative disorders such as Alzheimer and Parkinson diseases. We hypothesized that radiologic differences between NPH and AD/PD can be characterized by a robust and objective MR imaging DTI technique that does not require intersubject image registration or operator-defined regions of interest, thus avoiding many pitfalls common in DTI methods. MATERIALS AND METHODS: We collected 3T DTI data from 15 patients with probable NPH and 25 controls with AD, PD, or dementia with Lewy bodies. We developed a parametric model for the shape of intracranial mean diffusivity histograms that separates brain and ventricular components from a third component composed mostly of partial volume voxels. To accurately fit the shape of the third component, we constructed a parametric function named the generalized Voss-Dyke function. We then examined the use of the fitting parameters for the differential diagnosis of NPH from AD, PD, and DLB. RESULTS: Using parameters for the MD histogram shape, we distinguished clinically probable NPH from the 3 other disorders with 86% sensitivity and 96% specificity. The technique yielded 86% sensitivity and 88% specificity when differentiating NPH from AD only. CONCLUSIONS: An adequate parametric model for the shape of intracranial MD histograms can distinguish NPH from AD, PD, or DLB with high sensitivity and specificity.

21 Article GTPase activity regulates kinase activity and cellular phenotypes of Parkinson's disease-associated LRRK2. 2013

Biosa, Alice / Trancikova, Alzbeta / Civiero, Laura / Glauser, Liliane / Bubacco, Luigi / Greggio, Elisa / Moore, Darren J. ·Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fe´de´ rale de Lausanne (EPFL), Lausanne 1015, Switzerland. ·Hum Mol Genet · Pubmed #23241358.

ABSTRACT: Mutations in the LRRK2 gene cause autosomal dominant Parkinson's disease. LRRK2 encodes a multi-domain protein containing a Ras-of-complex (Roc) GTPase domain, a C-terminal of Roc domain and a protein kinase domain. LRRK2 can function as a GTPase and protein kinase, although the interplay between these two enzymatic domains is poorly understood. Although guanine nucleotide binding is critically required for the kinase activity of LRRK2, the contribution of GTP hydrolysis is not known. In general, the molecular determinants regulating GTPase activity and how the GTPase domain contributes to the properties of LRRK2 remain to be clarified. Here, we identify a number of synthetic missense mutations in the GTPase domain that functionally modulate GTP binding and GTP hydrolysis and we employ these mutants to comprehensively explore the contribution of GTPase activity to the kinase activity and cellular phenotypes of LRRK2. Our data demonstrate that guanine nucleotide binding and, to a lesser extent, GTP hydrolysis are required for maintaining normal kinase activity and both activities contribute to the GTP-dependent activation of LRRK2 kinase activity. Guanine nucleotide binding but not GTP hydrolysis regulates the dimerization, structure and stability of LRRK2. Furthermore, GTP hydrolysis regulates the LRRK2-dependent inhibition of neurite outgrowth in primary cortical neurons but is unable to robustly modulate the effects of the familial G2019S mutation. Our study elucidates the role of GTPase activity in regulating kinase activity and cellular phenotypes of LRRK2 and has important implications for the validation of the GTPase domain as a molecular target for attenuating LRRK2-mediated neurodegeneration.

22 Article Phosphorylation of 4E-BP1 in the mammalian brain is not altered by LRRK2 expression or pathogenic mutations. 2012

Trancikova, Alzbeta / Mamais, Adamantios / Webber, Philip J / Stafa, Klodjan / Tsika, Elpida / Glauser, Liliane / West, Andrew B / Bandopadhyay, Rina / Moore, Darren J. ·Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. ·PLoS One · Pubmed #23082216.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are a common cause of autosomal dominant familial Parkinson's disease (PD). LRRK2 encodes a multi-domain protein containing GTPase and kinase enzymatic domains. Disease-associated mutations in LRRK2 variably influence enzymatic activity with the common G2019S variant leading to enhanced kinase activity. Mutant LRRK2 induces neuronal toxicity through a kinase-dependent mechanism suggesting that kinase activity is important for mediating the pathogenic effects of LRRK2 mutations. A number of LRRK2 kinase substrates have been identified in vitro but whether they represent authentic physiological substrates in mammalian cells or tissues is not yet clear. The eukaryotic initiation factor 4E (eIF4E)-binding protein, 4E-BP1, was recently identified as a potential substrate of LRRK2 kinase activity in vitro and in Drosophila with phosphorylation occurring at Thr37 and Thr46. Here, we explore a potential interaction of LRRK2 and 4E-BP1 in mammalian cells and brain. We find that LRRK2 can weakly phosphorylate 4E-BP1 in vitro but LRRK2 overexpression is not able to alter endogenous 4E-BP1 phosphorylation in mammalian cells. In mammalian neurons LRRK2 and 4E-BP1 display minimal co-localization, whereas the subcellular distribution, protein complex formation and covalent post-translational modification of endogenous 4E-BP1 are not altered in the brains of LRRK2 knockout or mutant LRRK2 transgenic mice. In the brain, the phosphorylation of 4E-BP1 at Thr37 and Thr46 does not change in LRRK2 knockout or mutant LRRK2 transgenic mice, nor is 4E-BP1 phosphorylation altered in idiopathic or G2019S mutant PD brains. Collectively, our results suggest that 4E-BP1 is neither a major nor robust physiological substrate of LRRK2 in mammalian cells or brain.

23 Article GTPase activity and neuronal toxicity of Parkinson's disease-associated LRRK2 is regulated by ArfGAP1. 2012

Stafa, Klodjan / Trancikova, Alzbeta / Webber, Philip J / Glauser, Liliane / West, Andrew B / Moore, Darren J. ·Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. ·PLoS Genet · Pubmed #22363216.

ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common cause of autosomal dominant familial Parkinson's disease (PD) and also contribute to idiopathic PD. LRRK2 encodes a large multi-domain protein with GTPase and kinase activity. Initial data indicates that an intact functional GTPase domain is critically required for LRRK2 kinase activity. PD-associated mutations in LRRK2, including the most common G2019S variant, have variable effects on enzymatic activity but commonly alter neuronal process morphology. The mechanisms underlying the intrinsic and extrinsic regulation of LRRK2 GTPase and kinase activity, and the pathogenic effects of familial mutations, are incompletely understood. Here, we identify a novel functional interaction between LRRK2 and ADP-ribosylation factor GTPase-activating protein 1 (ArfGAP1). LRRK2 and ArfGAP1 interact in vitro in mammalian cells and in vivo in brain, and co-localize in the cytoplasm and at Golgi membranes. PD-associated and functional mutations that alter the GTPase activity of LRRK2 modulate the interaction with ArfGAP1. The GTP hydrolysis activity of LRRK2 is markedly enhanced by ArfGAP1 supporting a role for ArfGAP1 as a GTPase-activating protein for LRRK2. Unexpectedly, ArfGAP1 promotes the kinase activity of LRRK2 suggesting a potential role for GTP hydrolysis in kinase activation. Furthermore, LRRK2 robustly and directly phosphorylates ArfGAP1 in vitro. Silencing of ArfGAP1 expression in primary cortical neurons rescues the neurite shortening phenotype induced by G2019S LRRK2 overexpression, whereas the co-expression of ArfGAP1 and LRRK2 synergistically promotes neurite shortening in a manner dependent upon LRRK2 GTPase activity. Neurite shortening induced by ArfGAP1 overexpression is also attenuated by silencing of LRRK2. Our data reveal a novel role for ArfGAP1 in regulating the GTPase activity and neuronal toxicity of LRRK2; reciprocally, LRRK2 phosphorylates ArfGAP1 and is required for ArfGAP1 neuronal toxicity. ArfGAP1 may represent a promising target for interfering with LRRK2-dependent neurodegeneration in familial and sporadic PD.

24 Article PARK9-associated ATP13A2 localizes to intracellular acidic vesicles and regulates cation homeostasis and neuronal integrity. 2012

Ramonet, David / Podhajska, Agata / Stafa, Klodjan / Sonnay, Sarah / Trancikova, Alzbeta / Tsika, Elpida / Pletnikova, Olga / Troncoso, Juan C / Glauser, Liliane / Moore, Darren J. ·Laboratory of Molecular Neurodegenerative Research, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland. ·Hum Mol Genet · Pubmed #22186024.

ABSTRACT: Mutations in the ATP13A2 gene (PARK9, OMIM 610513) cause autosomal recessive, juvenile-onset Kufor-Rakeb syndrome and early-onset parkinsonism. ATP13A2 is an uncharacterized protein belonging to the P(5)-type ATPase subfamily that is predicted to regulate the membrane transport of cations. The physiological function of ATP13A2 in the mammalian brain is poorly understood. Here, we demonstrate that ATP13A2 is localized to intracellular acidic vesicular compartments in cultured neurons. In the human brain, ATP13A2 is localized to pyramidal neurons within the cerebral cortex and dopaminergic neurons of the substantia nigra. ATP13A2 protein levels are increased in nigral dopaminergic and cortical pyramidal neurons of Parkinson's disease brains compared with normal control brains. ATP13A2 levels are increased in cortical neurons bearing Lewy bodies (LBs) compared with neurons without LBs. Using short hairpin RNA-mediated silencing or overexpression to explore the function of ATP13A2, we find that modulating the expression of ATP13A2 reduces the neurite outgrowth of cultured midbrain dopaminergic neurons. We also find that silencing of ATP13A2 expression in cortical neurons alters the kinetics of intracellular pH in response to cadmium exposure. Furthermore, modulation of ATP13A2 expression leads to reduced intracellular calcium levels in cortical neurons. Finally, we demonstrate that silencing of ATP13A2 expression induces mitochondrial fragmentation in neurons. Oppositely, overexpression of ATP13A2 delays cadmium-induced mitochondrial fragmentation in neurons consistent with a neuroprotective effect. Collectively, this study reveals a number of intriguing neuronal phenotypes due to the loss- or gain-of-function of ATP13A2 that support a role for this protein in regulating intracellular cation homeostasis and neuronal integrity.

25 Article Parkin promotes the ubiquitination and degradation of the mitochondrial fusion factor mitofusin 1. 2011

Glauser, Liliane / Sonnay, Sarah / Stafa, Klodjan / Moore, Darren J. ·Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. ·J Neurochem · Pubmed #21615408.

ABSTRACT: Mutations in the parkin gene cause early-onset, autosomal recessive Parkinson's disease. Parkin functions as an E3 ubiquitin ligase to mediate the covalent attachment of ubiquitin monomers or linked chains to protein substrates. Substrate ubiquitination can target proteins for proteasomal degradation or can mediate a number of non-degradative functions. Parkin has been shown to preserve mitochondrial integrity in a number of experimental systems through the regulation of mitochondrial fission. Upon mitochondrial damage, parkin translocates to mitochondria to mediate their selective elimination by autophagic degradation. The mechanism underlying this process remains unclear. Here, we demonstrate that parkin interacts with and selectively mediates the atypical poly-ubiquitination of the mitochondrial fusion factor, mitofusin 1, leading to its enhanced turnover by proteasomal degradation. Our data supports a model whereby the translocation of parkin to damaged mitochondria induces the degradation of mitofusins leading to impaired mitochondrial fusion. This process may serve to selectively isolate damaged mitochondria for their removal by autophagy.

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