Center for Neurodegenerative and Neuroimmunologic Diseases

Piscataway, NJ, United States

Center for Neurodegenerative and Neuroimmunologic Diseases

Piscataway, NJ, United States
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Braithwaite S.P.,Signum Biosciences | Stock J.B.,Signum Biosciences | Stock J.B.,Princeton University | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Reviews in the Neurosciences | Year: 2012

Phosphorylation is a key post-translational modification necessary for normal cellular signaling and, therefore, lies at the heart of cellular function. In neurodegenerative disorders, abnormal hyperphosphorylation of pathogenic proteins is a common phenomenon that contributes in important ways to the disease process. A prototypical protein that is hyperphosphorylated in the brain is α-synuclein (α-syn) - found in Lewy bodies and Lewy neurites - the pathological hallmarks of Parkinson's disease (PD) and other α-synucleinopathies. The genetic linkage of α-syn to PD as well as its pathological association in both genetic and sporadic cases have made it the primary protein of interest. In understanding how α-syn dysfunction occurs, increasing focus is being placed on its abnormal aggregation and the contribution of phosphorylation to this process. Studies of both the kinases and phosphatases that regulate α-syn phosphorylation are beginning to reveal the roles of this post-translational modification in disease pathogenesis. Modulation of α-syn phosphorylation may ultimately prove to be a viable strategy for disease-modifying therapeutic interventions. In this review, we explore mechanisms related to α-syn phosphorylation, its biophysical and functional consequences, and its role in neurodegeneration. © 2012 by Walter de Gruyter Berlin Boston.


Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Neurobiology of Disease | Year: 2012

Besides the classic mutations in coding regions of genes, the critical role of gene expression regulators in disease states is increasingly recognized. The network of small non-coding microRNAs is crucial for the normal development and survival of distinct neuronal populations that are vulnerable in various neurodegenerative disorders. In midbrain dopaminergic neurons, which degenerate in Parkinson's disease (PD) causing motor signs and symptoms, disruption of this network results in their progressive loss associated with impaired motor activity in Drosophila and mouse models. Studies of families with dominantly inherited PD linked to multiplication of the α-synuclein gene locus indicate that the amount of this key pathogenic protein in neurons is an important determinant of its tendency to aggregate pathologically and increase neuronal susceptibility. Recent reports demonstrate that the α-synuclein mRNA is under negative control by at least two microRNAs, miR-7 and miR-153. In addition to studying the regulation of candidate genes by specific microRNA species, different profiling approaches are uncovering variations in the abundance of certain microRNAs that may prove to be relevant to the disease. For example, miR-133b is deficient in the PD midbrain as well as in mouse models, and miR-34b/34c are decreased in several affected brain regions in PD and incidental Lewy body disease. Polymorphisms in the 3'-untranslated region of microRNA target mRNAs, including in the gene encoding α-synuclein found in Genome Wide Association studies, are another potential reason for variations in the rate of protein production and thus disease risk. And finally, the impact of a disease associated gene product, and in particular LRRK2, on the microRNA network compounds the complexity of the interplay between the microRNA system and pathogenic proteins. The wealth of knowledge accumulating from these studies in a few short years holds considerable promise to harness its potential and translate it into therapeutic strategies for PD. © 2012 Elsevier Inc.


Braithwaite S.P.,Signum Biosciences | Voronkov M.,Signum Biosciences | Stock J.B.,Signum Biosciences | Stock J.B.,Princeton University | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Neurochemistry International | Year: 2012

Phosphorylation is a key post-translational modification for cellular signaling, and abnormalities in this process are observed in several neurodegenerative disorders. Among these disorders, Parkinson's disease (PD) is particularly intriguing as there are both genetic causes of disease that involve phosphorylation, and pathological hallmarks of disease composed of a hyperphosphorylated protein. Two of the major genes linked to PD are themselves kinases - leucine rich repeat kinase 2 (LRRK2) and phosphatase and tensin induced homolog kinase 1 (PINK1). Mutations in LRRK2 lead to its increased kinase activity and dominantly inherited PD, while mutations in PINK1 lead to loss of function and recessive PD. A third genetic linkage to disease is α-synuclein, a protein that is heavily phosphorylated in Lewy bodies and Lewy neurites, the pathological hallmarks of PD. The phosphorylation of α-synuclein at various residues influences its aggregation, either positively or negatively, thereby impacting its central role in disease pathogenesis. Given these associations of phosphorylation with PD, modulation of this modification is an attractive therapeutic strategy. The kinases that act in these disease relevant pathways have been the primary target for such approaches. But, the development of kinase inhibitors has been complicated by the necessary specificity to retain safety, the redundancy of kinases leading to lack of efficacy, and the difficulties in overcoming the blood-brain barrier. The field of modulating phosphatases has the potential to overcome some of these issues and provide the next generation of therapeutic targets for PD. In this review, we address the phosphorylation pathways involved in PD, the kinases and issues related to their inhibition, and the evolving field of the phosphatases relevant in PD and how they may be targeted pharmacologically. © 2011 Elsevier Ltd. All rights reserved.


Kabaria S.,Center for Neurodegenerative and Neuroimmunologic Diseases | Choi D.C.,Center for Neurodegenerative and Neuroimmunologic Diseases | Chaudhuri A.D.,Center for Neurodegenerative and Neuroimmunologic Diseases | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases | Junn E.,Center for Neurodegenerative and Neuroimmunologic Diseases
FEBS Letters | Year: 2015

Mounting evidence suggests that microRNA (miR) dysregulation contributes to neurodegenerative disorders including Parkinson's disease (PD). MiR-34b and miR-34c have been previously shown to be down-regulated in the brains of patients with PD. Here, we demonstrate that miR-34b and miR-34c repress the expression of α-synuclein (α-syn), a key protein in PD pathogenesis. Inhibition of miR-34b and miR-34c expression in human dopaminergic SH-SY5Y cells increased α-syn levels and stimulated aggregate formation. Additionally, a single nucleotide polymorphism (SNP) in the 3′-UTR of α-syn was found to lower the miR-34b-mediated repression of the protein. Our results suggest that down-regulation of miR-34b and miR-34c in the brain, as well as an SNP in the 3′-UTR of α-syn can increase α-syn expression, possibly contributing to PD pathogenesis. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.


Junn E.,Center for Neurodegenerative and Neuroimmunologic Diseases | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Cell Cycle | Year: 2010

MicroRNAs (miRNAs) are endogenous, small, noncoding RNAs regulating eukaryotic gene expression at the post-transcriptional level. During the last decade, considerable advances have been made in our understanding the biogenesis of miRNAs, the molecular mechanisms by which they regulate gene expression and their functional role in various physiological situations. miRNAs are abundant in the brain where they have crucial roles in development and synaptic plasticity. Accumulating evidence from postmortem brain analyses and animal model studies has begun to suggest that miRNA dysfunction contributes to neurodegenerative disorders. Here, we discuss several examples of investigations demonstrating the role of miRNAs in neurodegenerative disorders. As the expression of disease-causing genes is regulated by certain miRNA(s), changes in these miRNAs could lead to the accumulation of disease-causing proteins, and subsequently to neuronal dysfunction and death. Detailed understanding of these mechanisms can provide potential new therapeutic approaches to slow down or halt the progression of neurodegenerative diseases. © 2010 Landes Bioscience.


Wider C.,University of Lausanne | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Neurology | Year: 2015

Parkinson disease (PD) and other Lewy body disorders are common neurodegenerative conditions manifesting with progressive motor and nonmotor symptoms. Although their pathogenesis remains to be fully elucidated, a number of genetic findings have helped better understand the molecular mechanisms involved.1 Mutations in genes causing PD that are inherited in a Mendelian fashion as well as genetic variants that modify disease risk have been identified, some overlapping with those involved in other Lewy body disorders. Recently, mutations in a gene named coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) were found in Japanese patients from families with autosomal dominantly inherited PD.2 Moreover, a patient-control analysis suggested that variants in CHCHD2 associate with increased risk for sporadic, late-onset PD.2 These findings have raised strong interest given that (1) the CHCHD2 protein is localized in mitochondria and (2) mitochondrial dysfunction plays an important role in PD, particularly early-onset PD due to mutations in PINK1 and PARKIN.3 © 2015 American Academy of Neurology.


Junn E.,Center for Neurodegenerative and Neuroimmunologic Diseases | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Pharmacology and Therapeutics | Year: 2012

MicroRNAs (miRNAs) are abundant, endogenous, short, noncoding RNAs that act as important post-transcriptional regulators of gene expression by base-pairing with their target mRNA. During the last decade, substantial knowledge has accumulated regarding the biogenesis of miRNAs, their molecular mechanisms and functional roles in a variety of cellular contexts. Altered expression of certain miRNA molecules in the brains of patients with neurodegenerative diseases such as Alzheimer and Parkinson suggests that miRNAs could have a crucial regulatory role in these disorders. Polymorphisms in miRNA target sites may also constitute an important determinant of disease risk. Additionally, emerging evidence points to specific miRNAs targeting and regulating the expression of particular proteins that are key to disease pathogenesis. Considering that the amount of these proteins in susceptible neuronal populations appears to be critical to neurodegeneration, miRNA-mediated regulation represents a new target of significant therapeutic prospects. In this review, the implications of miRNAs in several neurodegenerative disorders and their potential as therapeutic interventions are discussed. © 2011 Elsevier Inc. © 2011 Elsevier Inc. All rights reserved.


Dias V.,Center for Neurodegenerative and Neuroimmunologic Diseases | Junn E.,Center for Neurodegenerative and Neuroimmunologic Diseases | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Journal of Parkinson's Disease | Year: 2013

Oxidative stress plays an important role in the degeneration of dopaminergic neurons in Parkinson's disease (PD). Disruptions in the physiologic maintenance of the redox potential in neurons interfere with several biological processes, ultimately leading to cell death. Evidence has been developed for oxidative and nitrative damage to key cellular components in the PD substantia nigra. A number of sources and mechanisms for the generation of reactive oxygen species (ROS) are recognized including the metabolism of dopamine itself, mitochondrial dysfunction, iron, neuroinflammatory cells, calcium, and aging. PD causing gene products including DJ-1, PINK1, parkin, alpha-synuclein and LRRK2 also impact in complex ways mitochondrial function leading to exacerbation of ROS generation and susceptibility to oxidative stress. Additionally, cellular homeostatic processes including the ubiquitin-proteasome system and mitophagy are impacted by oxidative stress. It is apparent that the interplay between these various mechanisms contributes to neurodegeneration in PD as a feed forward scenario where primary insults lead to oxidative stress, which damages key cellular pathogenetic proteins that in turn cause more ROS production. Animal models of PD have yielded some insights into the molecular pathways of neuronal degeneration and highlighted previously unknown mechanisms by which oxidative stress contributes to PD. However, therapeutic attempts to target the general state of oxidative stress in clinical trials have failed to demonstrate an impact on disease progression. Recent knowledge gained about the specific mechanisms related to PD gene products that modulate ROS production and the response of neurons to stress may provide targeted new approaches towards neuroprotection. © 2013 -IOS Press and the authors.


Grosso H.,Center for Neurodegenerative and Neuroimmunologic Diseases | Mouradian M.M.,Center for Neurodegenerative and Neuroimmunologic Diseases
Pharmacology and Therapeutics | Year: 2012

Neurodegenerative disorders are characterized by progressive neuronal loss and the aggregation of disease-specific pathogenic proteins in hallmark neuropathologic lesions. Many of these proteins, including amyloid Αβ, tau, α-synuclein and huntingtin, are cross-linked by the enzymatic activity of transglutaminase 2 (TG2). Additionally, the expression and activity of TG2 is increased in affected brain regions in these disorders. These observations along with experimental evidence in cellular and mouse models suggest that TG2 can contribute to the abnormal aggregation of disease causing proteins and consequently to neuronal damage. This accumulating evidence has provided the impetus to develop inhibitors of TG2 as possible neuroprotective agents. However, TG2 has other enzymatic activities in addition to its cross-linking function and can modulate multiple cellular processes including apoptosis, autophagy, energy production, synaptic function, signal transduction and transcription regulation. These diverse properties must be taken into consideration in designing TG2 inhibitors. In this review, we discuss the biochemistry of TG2, its various physiologic functions and our current understanding about its role in degenerative diseases of the brain. We also describe the different approaches to designing TG2 inhibitors that could be developed as potential disease-modifying therapies. © 2012 Elsevier Inc. All rights reserved.


Choi D.C.,Center for Neurodegenerative and Neuroimmunologic Diseases | Chae Y.-J.,Center for Neurodegenerative and Neuroimmunologic Diseases | Kabaria S.,Center for Neurodegenerative and Neuroimmunologic Diseases | Chaudhuri A.D.,Center for Neurodegenerative and Neuroimmunologic Diseases | And 4 more authors.
Journal of Neuroscience | Year: 2014

Parkinson’s disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Mitochondrial complex I impairment in PD is modeled in vitro by the susceptibility of dopaminergic neurons to the complex I inhibitor 1-methyl-4-phenylpyridinium (MPP). In the present study, we demonstrate that microRNA-7 (miR-7), which is expressed in tyrosine hydroxylase-positive nigral neurons in mice and humans, protects cells from MPP -induced toxicity in dopaminergic SH-SY5Y cells, differentiated human neural progenitor ReNcell VM cells, and primary mouse neurons. RelA, a component of nuclear factor-κB (NF-κB), was identified to be downregulated by miR-7 using quantitative proteomic analysis. Through a series of validation experiments, it was confirmed that RelA mRNA is a target of miR-7 and is required for cell death following MPP exposure. Further, RelA mediates MPP –induced suppression of NF-κB activity, which is essential for MPP -induced cell death. Accordingly, the protective effect of miR-7 is exerted through relieving NF-κB suppression by reducing RelA expression. These findings provide a novel mechanism by which NF-κB suppression, rather than activation, underlies the cell death mechanism following MPP toxicity, have implications for the pathogenesis of PD, and suggest miR-7 as a therapeutic target for this disease. © 2014 the authors.

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