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Iba M, Kim C, Florio J, Mante M, Adame A, Rockenstein E, Kwon S, Rissman R, Masliah E. Role of Alterations in Protein Kinase p38γ in the Pathogenesis of the Synaptic Pathology in Dementia With Lewy Bodies and α-Synuclein Transgenic Models. Front Neurosci 2020; 14:286. [PMID: 32296304 PMCID: PMC7138105 DOI: 10.3389/fnins.2020.00286] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/12/2020] [Indexed: 12/15/2022] Open
Abstract
Progressive accumulation of the pre-synaptic protein α-synuclein (α-syn) has been strongly associated with the pathogenesis of neurodegenerative disorders of the aging population such as Alzheimer's disease (AD), Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy. While the precise mechanisms are not fully understood, alterations in kinase pathways including that of mitogen activated protein kinase (MAPK) p38 have been proposed to play a role. In AD, p38α activation has been linked to neuro-inflammation while alterations in p38γ have been associated with tau phosphorylation. Although p38 has been studied in AD, less is known about its role in DLB/PD and other α-synucleinopathies. For this purpose, we investigated the expression of the p38 family in brains from α-syn overexpressing transgenic mice (α-syn Tg: Line 61) and patients with DLB/PD. Immunohistochemical analysis revealed that in healthy human controls and non-Tg mice, p38α associated with neurons and astroglial cells and p38γ localized to pre-synaptic terminals. In DLB and α-syn Tg brains, however, p38α levels were increased in astroglial cells while p38γ immunostaining was redistributed from the synaptic terminals to the neuronal cell bodies. Double immunolabeling further showed that p38γ colocalized with α-syn aggregates in DLB patients, and immunoblot and qPCR analysis confirmed the increased levels of p38α and p38γ. α1-syntrophin, a synaptic target of p38γ, was present in the neuropil and some neuronal cell bodies in human controls and non-Tg mice. In DLB and and Tg mice, however, α1-syntrophin was decreased in the neuropil and instead colocalized with α-syn in intra-neuronal inclusions. In agreement with these findings, in vitro studies showed that α-syn co-immunoprecipitates with p38γ, but not p38α. These results suggest that α-syn might interfere with the p38γ pathway and play a role in the mechanisms of synaptic dysfunction in DLB/PD.
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Affiliation(s)
- Michiyo Iba
- Laboratory of Neurogenetics, Molecular Neuropathology Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States
| | - Changyoun Kim
- Laboratory of Neurogenetics, Molecular Neuropathology Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States
| | - Jazmin Florio
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Michael Mante
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Anthony Adame
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Edward Rockenstein
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Somin Kwon
- Laboratory of Neurogenetics, Molecular Neuropathology Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States
| | - Robert Rissman
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Eliezer Masliah
- Laboratory of Neurogenetics, Molecular Neuropathology Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States
- Division of Neuroscience, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States
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Follett J, Fox JD, Gustavsson EK, Kadgien C, Munsie LN, Cao LP, Tatarnikov I, Milnerwood AJ, Farrer MJ. DNAJC13 p.Asn855Ser, implicated in familial parkinsonism, alters membrane dynamics of sorting nexin 1. Neurosci Lett 2019; 706:114-122. [PMID: 31082451 DOI: 10.1016/j.neulet.2019.04.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 04/10/2019] [Accepted: 04/20/2019] [Indexed: 10/26/2022]
Abstract
DNAJC13 (RME-8) is a core co-chaperone that facilitates membrane recycling and cargo sorting of endocytosed proteins. DNAJ/Hsp40 (heat shock protein 40) proteins are highly conserved throughout evolution and mediate the folding of nascent proteins, and the unfolding, refolding or degradation of misfolded proteins while assisting in associated-membrane translocation. DNAJC13 is one of five DNAJ 'C' class chaperone variants implicated in monogenic parkinsonism. Here we examine the effect of the DNAJC13 disease-linked mutation (p.Asn855Ser) on its interacting partners, focusing on sorting nexin 1 (SNX1) membrane dynamics in primary cortical neurons derived from a novel Dnajc13 p.Asn855Ser knock-in (DKI) mouse model. Dnajc13 p.Asn855Ser mutant and wild type protein expression were equivalent in mature heterozygous cultures (DIV21). While SNX1-positive puncta density, area, and WASH-retromer assembly were comparable between cultures derived from DKI and wild type littermates, the formation of SNX1-enriched tubules in DKI neuronal cultures was significantly increased. Thus, Dnajc13 p.Asn855Ser disrupts SNX1 membrane-tubulation and trafficking, analogous to results from RME-8 depletion studies. The data suggest the mutation confers a dominant-negative gain-of-function in RME-8. Implications for the pathogenesis of Parkinson's disease are discussed.
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Affiliation(s)
- Jordan Follett
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada.
| | - Jesse D Fox
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada
| | - Emil K Gustavsson
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada; Department of Neurology, St. Olav's Hospital, Trondheim, Norway
| | - Chelsie Kadgien
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada
| | - Lise N Munsie
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada
| | - Li Ping Cao
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada
| | - Igor Tatarnikov
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada
| | - Austen J Milnerwood
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada
| | - Matthew J Farrer
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, B.C., Canada
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