Subcellular Localization of Wild-Type and Parkinson's Disease-Associated Mutant α-Synuclein in Human and Transgenic Mouse Brain (original) (raw)
Related papers
Annals of the New York Academy of Sciences, 2006
The 15-20 kDa synuclein (SYN) phosphoproteins are abundantly expressed in nervous tissue. Members of the family include ␣and -SYN, and the more distantly related ␥-SYN and synoretin. SYN genes have been identified in Torpedo, canary, and several mammalian species, indicating an evolutionary conserved role. Expression of ␣-SYN was found to be modulated in situations of neuronal remodeling, namely, songbird learning and after target ablation of dopaminergic striatonigral neurons in the rat. The presynaptic localization of ␣-SYN is further supportive of a direct physiological role in neuronal plasticity. The extensive synaptic co-localization of ␣and -SYN might indicate functional redundancy of these highly homologous synucleins. However, ␣-SYN was the only family member identified in Lewy bodies and cytoplasmic inclusions characteristic for multiple system atrophy. Moreover, ␣-SYN was genetically linked to familial Parkinson's disease. The two Parkinson's disease-associated mutations accelerated the intrinsic aggregation property of ␣-SYN in vitro. Post-translational modifications, such as phosphorylation and proteolysis, and/or interaction with other proteins, might regulate ␣-SYN fibril formation in vivo. Cytoskeletal elements and signal transduction intermediates have been recently identified as binding partners for ␣-SYN. Preliminary data available from transgenic mice suggest that (over)expressed human ␣-SYN proteins are less efficiently cleared from the neuronal cytosol. Thus, Parkinson's disease-associated mutations might perturb axonal transport, leading to somal accumulation of ␣-SYN and eventually Lewy body formation.
Functionally different α-synuclein inclusions yield insight into Parkinson’s disease pathology
Scientific Reports, 2016
The formation of α-synuclein (α-S) amyloid aggregates, called Lewy bodies (LBs), is a hallmark of Parkinson's disease (PD). The function of LBs in the disease process is however still unclear; they have been associated with both neuroprotection and toxicity. To obtain insight into this contradiction, we induced the formation of α-S inclusions, using three different induction methods in SH-SY5Y cells and rat-derived primary neuronal cells. Using confocal and STED microscopy we observed inductiondependent differences in α-S inclusion morphology, location and function. The aggregation of α-S in functionally different compartments correlates with the toxicity of the induction method measured in viability assays. The most cytotoxic treatment largely correlates with the formation of proteasomeassociated, juxta-nuclear inclusions. With less toxic methods cytosolic deposits that are not associated with the proteasome are more prevalent. The distribution of α-S over at least two different types of inclusions is not limited to cell models, but is also observed in primary neuronal cells and in human mesencephalon. The existence of functionally different LBs, in vivo and in vitro, gives important insights in the impact of Lewy Body formation on neuronal functioning and may thereby provide a platform for discovering therapeutics. The aggregation of soluble proteins into insoluble, β-sheet-rich amyloid fibrils is characteristic for many neurodegenerative diseases. Intraneuronal aggregates of α-synuclein (α-S) are for example found in Parkinson's disease (PD), Lewy body dementia and multiple system atrophy 1-3. Whereas extracellular β-amyloid deposits and intracellular accumulations of phosphorylated tau protein occur in Alzheimer's disease 4,5. In Huntington's disease, polyglutamine-expanded huntingtin (htt) protein accumulates within intranuclear inclusion bodies or neurites 6 and in amyotrophic lateral sclerosis, motor neurons develop protein-rich inclusions containing superoxide dismutase 1, TAR DNA-binding protein 43 or the RNA-binding protein fused-in-sarcoma in their cell bodies and axons 7-10. In PD, α-S amyloid inclusions such as Lewy neurites (LN) and Lewy bodies (LB) can be found in neurons and glia cells 2,3,11. The topographical progression of neuronal death, and the development of α-S immunoreactive Lewy body related structures 12,13 , here abbreviated to Lewy body like inclusions (LBLI), throughout the brain is used to stage PD pathology 14. The pathologically determined stages are in many cases related to clinical features observed in patients 15. Nevertheless, the role of LBLI during the progression of PD is unclear. LBLI may be indicative of cellular dysfunction and death 16,17 but have also been described as harmless, inert or neuroprotective protein aggregates 18. PD symptoms have been shown to directly correlate with the density of neurons in the substantia nigra pars compacta 19 , but no correlation could be established between the number of LBLI and the severity of disease symptoms 16. Assuming LBLI are indeed inert, one would expect the affected cells to have a normal life span. With the loss of other cells in the tissue 19 , the proportion of cells with LBLI should therefore
2010
The pathological hallmark of Parkinson's disease and diffuse Lewy body disease (DLBD) is the aggregation of ␣-synuclein (␣-syn) in the form of Lewy bodies and Lewy neurites. Patients with both Alzheimer's disease (AD) and cortical Lewy pathology represent the Lewy body variant of AD (LBV) and constitute 25% of AD cases. C-terminally truncated forms of ␣-syn enhance the aggregation of ␣-syn in vitro. To investigate the presence of C-terminally truncated ␣-syn in DLBD, AD , and LBV , we generated and validated polyclonal antibodies to truncated ␣-syn ending at residues 110 (␣-syn110) and 119 (␣-syn119) , two products of 20S proteosome-mediated endoproteolytic cleavage. Double immunofluorescence staining of the cingulate cortex showed that ␣-syn110 and ␣-syn140 (full-length) aggregates were not colocalized in LBV. All aggregates containing ␣-syn140 also contained ␣-syn119; however , some aggregates contained ␣-syn119 without ␣-syn140, suggesting that ␣-syn119 may stimulate aggregate formation. Immunohistochemistry and image analysis of tissue microarrays of the cingulate cortex from patients with DLBD (n ؍ 27) , LBV (n ؍ 27) , and AD (n ؍ 19) and age-matched controls (n ؍ 15) revealed that AD is also characterized by frequent abnormal neurites containing ␣-syn119. Notably , these neurites did not contain ␣-syn ending at residues 110 or 122-140. The presence of abnormal neurites containing ␣-syn119 in AD without conventional Lewy pathology suggests that AD and Lewy body disease may be more closely related than previ-ously thought.
Parkinson's disease -synuclein mutations exhibit defective axonal transport in cultured neurons
Journal of Cell Science, 2004
α-Synuclein is a major protein constituent of Lewy bodies and mutations in α-synuclein cause familial autosomal dominant Parkinson's disease. One explanation for the formation of perikaryal and neuritic aggregates of α-synuclein, which is a presynaptic protein, is that the mutations disrupt α-synuclein transport and lead to its proximal accumulation. We found that mutant forms of α-synuclein, either associated with Parkinson's disease (A30P or A53T) or mimicking defined serine, but not tyrosine, phosphorylation states exhibit reduced axonal transport following transfection into cultured neurons. Furthermore, transfection of A30P, but not wild-type, α-synuclein results in accumulation of the protein proximal to the cell body. We propose that the reduced axonal transport exhibited by the Parkinson's disease-associated α-synuclein mutants examined in this study might contribute to perikaryal accumulation of α-synuclein and hence Lewy body formation and neuritic abnormalitie...
Neuroscience Letters, 1999
A growing body of evidence suggests that the non-Ab component of Alzheimer's disease amyloid precursor protein (NACP) or a-synuclein contributes to the neurodegenerative processes in Alzheimer's disease (AD), Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In the present study antisera to the N terminus and the NAC domain of the asynuclein protein were employed to elucidate the expression pattern in brains of patients with AD, PD, DLB and control specimen. a-Synuclein exhibited an overall punctuate expression pro®le compatible with a synaptic function. Interestingly, while Lewy bodies were strongly immunoreactive, none of the a-synuclein antisera revealed staining in mature bamyloid plaques in AD. These observations suggest that a-synuclein does not contribute to late neurodegenerative processes in AD brains. q Neuroscience Letters 266 (1999) 213±216 0304-3940/99/$ -see front matter q
Modeling Parkinson’s Disease With the Alpha-Synuclein Protein
Frontiers in Pharmacology
Alpha-synuclein (a-Syn) is a key protein involved in Parkinson's disease (PD) pathology. PD is characterized by the loss of dopaminergic neuronal cells in the substantia nigra pars compacta and the abnormal accumulation and aggregation of a-Syn in the form of Lewy bodies and Lewy neurites. More precisely, the aggregation of a-Syn is associated with the dysfunctionality and degeneration of neurons in PD. Moreover, mutations in the SNCA gene, which encodes a-Syn, cause familial forms of PD and are the basis of sporadic PD risk. Given the role of the a-Syn protein in the pathology of PD, animal models that reflect the dopaminergic neuronal loss and the widespread and progressive formation of a-Syn aggregates in different areas of the brain constitute a valuable tool. Indeed, animal models of PD are important for understanding the molecular mechanisms of the disease and might contribute to the development and validation of new therapies. In the absence of animal models that faithfully reproduce human PD, in recent years, numerous animal models of PD based on a-Syn have been generated. In this review, we summarize the main features of the a-Syn pre-formed fibrils (PFFs) model and recombinant adenoassociated virus vector (rAAV) mediated a-Syn overexpression models, providing a detailed comparative analysis of both models. Here, we discuss how each model has contributed to our understanding of PD pathology and the advantages and weakness of each of them. Significance: Here, we show that injection of a-Syn PFFs and overexpression of a-Syn mediated by rAAV lead to a different pattern of PD pathology in rodents. First, a-Syn PFFs models trigger the Lewy body-like inclusions formation in brain regions directly interconnected with the injection site, suggesting that there is an inter-neuronal transmission of the a-Syn pathology. In contrast, rAAV-mediated a-Syn overexpression in the brain limits the a-Syn aggregates within the transduced neurons. Second, phosphorylated a-Syn inclusions obtained with rAAV are predominantly nuclear with a punctate appearance that becomes diffuse along the neuronal fibers, whereas a-Syn PFFs models lead to the formation of cytoplasmic aggregates of phosphorylated a-Syn reminiscent of Lewy bodies and Lewy neurites.
Parkinson's disease α-synuclein mutations exhibit defective axonal transport in cultured neurons
Journal of Cell Science, 2004
α-Synuclein is a major protein constituent of Lewy bodies and mutations in α-synuclein cause familial autosomal dominant Parkinson's disease. One explanation for the formation of perikaryal and neuritic aggregates of α-synuclein, which is a presynaptic protein, is that the mutations disrupt α-synuclein transport and lead to its proximal accumulation. We found that mutant forms of α-synuclein, either associated with Parkinson's disease (A30P or A53T) or mimicking defined serine, but not tyrosine, phosphorylation states exhibit reduced axonal transport following transfection into cultured neurons. Furthermore, transfection of A30P, but not wild-type, α-synuclein results in accumulation of the protein proximal to the cell body. We propose that the reduced axonal transport exhibited by the Parkinson's disease-associated α-synuclein mutants examined in this study might contribute to perikaryal accumulation of α-synuclein and hence Lewy body formation and neuritic abnormalitie...
F1000 - Post-publication peer review of the biomedical literature, 2013
Modifications to the gene encoding human ␣-synuclein have been linked to the development of Parkinson's disease. The highly conserved structure of ␣-synuclein suggests a functional interaction with membranes, and several lines of evidence point to a role in vesicle-related processes within nerve terminals. Using recombinant fusions of human ␣-synuclein, including new genetic tags developed for correlated light microscopy and electron microscopy (the tetracysteine-biarsenical labeling system or the new fluorescent protein for electron microscopy, MiniSOG), we determined the distribution of ␣-synuclein when overexpressed in primary neurons at supramolecular and cellular scales in three dimensions (3D). We observed specific association of ␣-synuclein with a large and otherwise poorly characterized membranous organelle system of the presynaptic terminal, as well as with smaller vesicular structures within these boutons. Furthermore, ␣-synuclein was localized to multiple elements of the protein degradation pathway, including multivesicular bodies in the axons and lysosomes within neuronal cell bodies. Examination of synapses in brains of transgenic mice overexpressing human ␣-synuclein revealed alterations of the presynaptic endomembrane systems similar to our findings in cell culture. Three-dimensional electron tomographic analysis of enlarged presynaptic terminals in several brain areas revealed that these terminals were filled with membrane-bounded organelles, including tubulovesicular structures similar to what we observed in vitro. We propose that ␣-synuclein overexpression is associated with hypertrophy of membrane systems of the presynaptic terminalpreviouslyshowntohavearoleinvesiclerecycling.Ourdatasupporttheconclusionthat␣-synucleinisinvolvedinprocessesassociated with the sorting, channeling, packaging, and transport of synaptic material destined for degradation.
Journal of Neuroscience, 2013
Modifications to the gene encoding human ␣-synuclein have been linked to the development of Parkinson's disease. The highly conserved structure of ␣-synuclein suggests a functional interaction with membranes, and several lines of evidence point to a role in vesicle-related processes within nerve terminals. Using recombinant fusions of human ␣-synuclein, including new genetic tags developed for correlated light microscopy and electron microscopy (the tetracysteine-biarsenical labeling system or the new fluorescent protein for electron microscopy, MiniSOG), we determined the distribution of ␣-synuclein when overexpressed in primary neurons at supramolecular and cellular scales in three dimensions (3D). We observed specific association of ␣-synuclein with a large and otherwise poorly characterized membranous organelle system of the presynaptic terminal, as well as with smaller vesicular structures within these boutons. Furthermore, ␣-synuclein was localized to multiple elements of the protein degradation pathway, including multivesicular bodies in the axons and lysosomes within neuronal cell bodies. Examination of synapses in brains of transgenic mice overexpressing human ␣-synuclein revealed alterations of the presynaptic endomembrane systems similar to our findings in cell culture. Three-dimensional electron tomographic analysis of enlarged presynaptic terminals in several brain areas revealed that these terminals were filled with membrane-bounded organelles, including tubulovesicular structures similar to what we observed in vitro. We propose that ␣-synuclein overexpression is associated with hypertrophy of membrane systems of the presynaptic terminalpreviouslyshowntohavearoleinvesiclerecycling.Ourdatasupporttheconclusionthat␣-synucleinisinvolvedinprocessesassociated with the sorting, channeling, packaging, and transport of synaptic material destined for degradation.