Publications by authors named "Anna Villar-Piqué"

46 Publications

Diagnostic and prognostic value of plasma neurofilament light and total-tau in sporadic Creutzfeldt-Jakob disease.

Alzheimers Res Ther 2021 Apr 21;13(1):86. Epub 2021 Apr 21.

Department of Neurology, National Reference Center for TSE Surveillance, University Medical Center, Robert-Koch Street 40, Göttingen, Germany.

Background: Blood neurofilament light (Nfl) and total-tau (t-tau) have been described to be increased in several neurological conditions, including prion diseases and other neurodegenerative dementias. Here, we aim to determine the accuracy of plasma Nfl and t-tau in the differential diagnosis of neurodegenerative dementias and their potential value as prognostic markers of disease severity.

Methods: Plasma Nfl and t-tau were measured in healthy controls (HC, n = 70), non-neurodegenerative neurological disease with (NND-Dem, n = 17) and without dementia syndrome (NND, n = 26), Alzheimer's disease (AD, n = 44), Creutzfeldt-Jakob disease (CJD, n = 83), dementia with Lewy bodies/Parkinson's disease with dementia (DLB/PDD, n = 35), frontotemporal dementia (FTD, n = 12), and vascular dementia (VaD, n = 22). Biomarker diagnostic accuracies and cutoff points for the diagnosis of CJD were calculated, and associations between Nfl and t-tau concentrations with other fluid biomarkers, demographic, genetic, and clinical data in CJD cases were assessed. Additionally, the value of Nfl and t-tau predicting disease survival in CJD was evaluated.

Results: Among diagnostic groups, highest plasma Nfl and t-tau concentrations were detected in CJD (fold changes of 38 and 18, respectively, compared to HC). Elevated t-tau was able to differentiate CJD from all other groups, whereas elevated Nfl concentrations were also detected in NND-Dem, AD, DLB/PDD, FTD, and VaD compared to HC. Both biomarkers discriminated CJD from non-CJD dementias with an AUC of 0.93. In CJD, plasma t-tau, but not Nfl, was associated with PRNP codon 129 genotype and CJD subtype. Positive correlations were observed between plasma Nfl and t-tau concentrations, as well as between plasma and CSF concentrations of both biomarkers (p < 0.001). Nfl was increased in rapidly progressive AD (rpAD) compared to slow progressive AD (spAD) and associated to Mini-Mental State Examination results. However, Nfl displayed higher accuracy than t-tau discriminating CJD from rpAD and spAD. Finally, plasma t-tau, but not plasma Nfl, was significantly associated with disease duration, offering a moderate survival prediction capacity.

Conclusions: Plasma Nfl and t-tau are useful complementary biomarkers for the differential diagnosis of CJD. Additionally, plasma t-tau emerges as a potential prognostic marker of disease duration.
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http://dx.doi.org/10.1186/s13195-021-00815-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8059191PMC
April 2021

TREM2 expression in the brain and biological fluids in prion diseases.

Acta Neuropathol 2021 Apr 21. Epub 2021 Apr 21.

Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), L'Hospitalet de Llobregat, Spain.

Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune cell surface receptor that regulates microglial function and is involved in the pathophysiology of several neurodegenerative diseases. Its soluble form (sTREM2) results from shedding of the TREM2 ectodomain. The role of TREM2 in prion diseases, a group of rapidly progressive dementias remains to be elucidated. In the present study, we analysed the expression of TREM2 and its main sheddase ADAM10 in the brain of sporadic Creutzfeldt-Jakob disease (sCJD) patients and evaluated the role of CSF and plasma sTREM2 as a potential diagnostic marker of prion disease. Our data indicate that, compared to controls, TREM2 is increased in sCJD patient brains at the mRNA and protein levels in a regional and subtype dependent fashion, and expressed in a subpopulation of microglia. In contrast, ADAM10 is increased at the protein, but not the mRNA level, with a restricted neuronal expression. Elevated CSF sTREM2 is found in sCJD, genetic CJD with mutations E200K and V210I in the prion protein gene (PRNP), and iatrogenic CJD, as compared to healthy controls (HC) (AUC = 0.78-0.90) and neurological controls (AUC = 0.73-0.85), while CSF sTREM2 is unchanged in fatal familial insomnia. sTREM2 in the CSF of cases with Alzheimer's disease, and multiple sclerosis was not significantly altered in our series. CSF sTREM2 concentrations in sCJD are PRNP codon 129 and subtype-related, correlate with CSF 14-3-3 positivity, total-tau and YKL-40, and increase with disease progression. In plasma, sTREM2 is increased in sCJD compared with HC (AUC = 0.80), displaying positive correlations with plasma total-tau, neurofilament light, and YKL-40. We conclude that comparative study of TREM2 in brain and biological fluids of prion diseases reveals TREM2 to be altered in human prion diseases with a potential value in target engagement, patient stratification, and disease monitoring.
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http://dx.doi.org/10.1007/s00401-021-02296-1DOI Listing
April 2021

Optimization of the Real-Time Quaking-Induced Conversion Assay for Prion Disease Diagnosis.

Front Bioeng Biotechnol 2020 19;8:586890. Epub 2020 Nov 19.

Department of Neurology, German Center for Neurodegenerative Diseases (DZNE), University Medical Center Göttingen, Göttingen, Germany.

The real-time quaking-induced conversion (RT-QuIC) assay is a highly reproducible and robust methodology exhibiting an excellent pre-mortem diagnostic accuracy for prion diseases. However, the protocols might be time-consuming and improvement of the detection technology is needed. In the present study, we investigated the influence of a pre-analytical cerebrospinal fluid (CSF) treatment with proteinase K (PK) on the kinetic of the RT-QuIC signal response. For this purpose, we added PK at different concentrations in RT-QuIC reactions seeded with Creutzfeldt-Jakob disease (sCJD) CSF. We observed that a mild pre-analytical PK treatment of CSF samples resulted in an increased seeding efficiency of the RT-QuIC reaction. Quantitative seeding parameters, such as a higher area under the curve (AUC) value or a shorter lag phase indicated a higher conversion efficiency after treatment. The diagnostic accuracy resulting from 2 μg/ml PK treatment was analyzed in a retrospective study, where we obtained a sensitivity of 89%. Additionally, we analyzed the agreement with the previously established standard RT-QuIC protocol without PK treatment in a prospective study. Here, we found an overall agreement of 94% to 96%. A Cohen's kappa of 0.9036 (95% CI: 0.8114-0.9958) indicates an almost perfect agreement between both protocols. In conclusion, the outcome of our study can be used for a further optimization of the RT-QuIC assay in particular for a reduction of the testing time.
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http://dx.doi.org/10.3389/fbioe.2020.586890DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710546PMC
November 2020

A prognostic model for overall survival in sporadic Creutzfeldt-Jakob disease.

Alzheimers Dement 2020 10 2;16(10):1438-1447. Epub 2020 Jul 2.

Department of Neurology, University Medical School, Göttingen, Germany.

Introduction: We developed a prognostic model for overall survival after diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) using data from a German surveillance study.

Methods: We included 1226 sCJD cases (median age 66 years, range 19-89 years; 56.8% women with information on age, sex, codon 129 genotype, 14-3-3 in the cerebrospinal fluid (CSF), and CSF tau concentrations. The prognostic accuracy for overall survival was measured by the c statistics of multivariable Cox proportional hazard models. A score chart was derived to predict 6-month survival and median survival time.

Results: A model containing age, sex, codon 129 genotype, and CSF tau (with two-way interactions) was selected as the model with the highest c statistic (0.686, 95% confidence interval: 0.665-0.707) in a cross-validation approach.

Discussion: We developed the first prognostic model for overall survival of sCJD patients based on readily available information only. The developed score chart serves as a hands-on prediction tool for clinical practice.
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http://dx.doi.org/10.1002/alz.12133DOI Listing
October 2020

A new tetra-plex fluorimetric assay for the quantification of cerebrospinal fluid β-amyloid42, total-tau, phospho-tau and α-synuclein in the differential diagnosis of neurodegenerative dementia.

J Neurol 2020 Sep 5;267(9):2567-2581. Epub 2020 May 5.

Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Barcelona, Spain.

Background: Differential diagnosis of neurodegenerative dementia is currently supported by biomarkers including cerebrospinal fluid (CSF) tests. Among them, CSF total-tau (t-tau), phosphorylated tau (p-tau) and β-amyloid42 (Aβ42) are considered core biomarkers of neurodegeneration. In the present work, we hypothesize that simultaneous assessment of these biomarkers together with CSF α-synuclein (α-syn) will significantly improve the differential diagnostic of Alzheimer's disease and other dementias. To that aim, we characterized the analytical and clinical performance of a new tetra-plex immunoassay that simultaneously quantifies CSF Aβ42, t-tau, p-tau and α-syn in the differential diagnosis of neurodegenerative dementia.

Methods: Biomarkers' concentrations were measured in neurological controls (n = 38), Alzheimer's disease (n = 35), Creutzfeldt-Jakob disease (n = 37), vascular dementia (n = 28), dementia with Lewy bodies/Parkinson's disease dementia (n = 27) and frontotemporal dementia (n = 34) using the new tetra-plex assay and established single-plex assays. Biomarker's performance was evaluated and diagnostic accuracy in the discrimination of diagnostic groups was determined using partial least squares discriminant analysis.

Results: The tetra-plex assay presented accuracies similar to individual single-plex assays with acceptable analytical performance. Significant correlations were observed between tetra-plex and single-plex assays. Using partial least squares discriminant analysis, Alzheimer's disease and Creutzfeldt-Jakob disease were well differentiated, reaching high accuracies in the discrimination from the rest of diagnostic groups.

Conclusions: The new tetra-plex assay coupled with multivariate analytical approaches becomes a valuable asset for the differential diagnosis of neurodegenerative dementia and related applications.
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http://dx.doi.org/10.1007/s00415-020-09870-9DOI Listing
September 2020

Diagnostic Accuracy of Prion Disease Biomarkers in Iatrogenic Creutzfeldt-Jakob Disease.

Biomolecules 2020 02 12;10(2). Epub 2020 Feb 12.

Department of Neurology, National Reference Center for CJD Surveillance, University Medical Centre Göttingen, 37075 Göttingen, Germany.

Human prion diseases are classified into sporadic, genetic, and acquired forms. Within this last group, iatrogenic Creutzfeldt-Jakob disease (iCJD) is caused by human-to-human transmission through surgical and medical procedures. After reaching an incidence peak in the 1990s, it is believed that the iCJD historical period is probably coming to an end, thanks to lessons learnt from past infection sources that promoted new prion prevention and decontamination protocols. At this point, we sought to characterise the biomarker profile of iCJD and compare it to that of sporadic CJD (sCJD) for determining the value of available diagnostic tools in promptly recognising iCJD cases. To that end, we collected 23 iCJD samples from seven national CJD surveillance centres and analysed the electroencephalogram and neuroimaging data together with a panel of seven CSF biomarkers: 14-3-3, total tau, phosphorylated/total tau ratio, alpha-synuclein, neurofilament light, YKL-40, and real-time quaking induced conversion of prion protein. Using the cut-off values established for sCJD, we found the sensitivities of these biomarkers for iCJD to be similar to those described for sCJD. Given the limited relevant information on this issue to date, the present study validates the use of current sCJD biomarkers for the diagnosis of future iCJD cases.
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http://dx.doi.org/10.3390/biom10020290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072321PMC
February 2020

Cerebrospinal fluid lipocalin 2 as a novel biomarker for the differential diagnosis of vascular dementia.

Nat Commun 2020 01 30;11(1):619. Epub 2020 Jan 30.

Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.

The clinical diagnosis of vascular dementia (VaD) is based on imaging criteria, and specific biochemical markers are not available. Here, we investigated the potential of cerebrospinal fluid (CSF) lipocalin 2 (LCN2), a secreted glycoprotein that has been suggested as mediating neuronal damage in vascular brain injuries. The study included four independent cohorts with a total n = 472 samples. LCN2 was significantly elevated in VaD compared to controls, Alzheimer's disease (AD), other neurodegenerative dementias, and cognitively unimpaired patients with cerebrovascular disease. LCN2 discriminated VaD from AD without coexisting VaD with high accuracy. The main findings were consistent over all cohorts. Neuropathology disclosed a high percentage of macrophages linked to subacute infarcts, reactive astrocytes, and damaged blood vessels in multi-infarct dementia when compared to AD. We conclude that CSF LCN2 is a promising candidate biochemical marker in the differential diagnosis of VaD and neurodegenerative dementias.
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http://dx.doi.org/10.1038/s41467-020-14373-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6992814PMC
January 2020

Effect of the micro-environment on α-synuclein conversion and implication in seeded conversion assays.

Transl Neurodegener 2020 17;9. Epub 2020 Jan 17.

1Department of Neurology, University Medicine Goettingen and the German Center for Neurodegenerative Diseases (DZNE), Robert-Koch -Straße 40, 37075 Göttingen, Germany.

Background: α-Synuclein is a small soluble protein, whose physiological function in the healthy brain is poorly understood. Intracellular inclusions of α-synuclein, referred to as Lewy bodies (LBs), are pathological hallmarks of α-synucleinopathies, such as Parkinson's disease (PD) or dementia with Lewy bodies (DLB).

Main Body: Understanding of the molecular basis as well as the factors or conditions promoting α-synuclein misfolding and aggregation is an important step towards the comprehension of pathological mechanism of α-synucleinopathies and for the development of efficient therapeutic strategies. Based on the conversion and aggregation mechanism of α-synuclein, novel diagnostic tests, such as protein misfolding seeded conversion assays, e.g. the real-time quaking-induced conversion (RT-QuIC), had been developed. In diagnostics, α-synuclein RT-QuIC exhibits a specificity between 82 and 100% while the sensitivity varies between 70 and 100% among different laboratories. In addition, the α-synuclein RT-QuIC can be used to study the α-synuclein-seeding-characteristics of different α-synucleinopathies and to differentiate between DLB and PD.

Conclusion: The variable diagnostic accuracy of current α-synuclein RT-QuIC occurs due to different protocols, cohorts and material etc.. An impact of micro-environmental factors on the α-synuclein aggregation and conversion process and the occurrence and detection of differential misfolded α-synuclein types or strains might underpin the clinical heterogeneity of α-synucleinopathies
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http://dx.doi.org/10.1186/s40035-019-0181-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966864PMC
January 2020

Validation of Poly(Propylene Imine) Glycodendrimers Towards Their Anti-prion Conversion Efficiency.

Mol Neurobiol 2020 Apr 17;57(4):1863-1874. Epub 2019 Dec 17.

Department of Neurology, University Medicine Goettingen and the German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.

Prion diseases, such as the sporadic Creutzfeldt-Jakob disease (sCJD), are a class of fatal neurodegenerative disorders. Currently, there is no efficient treatment or therapy available. Hence, the search for molecules that may inhibit the conversion of the cellular prion protein (PrP) into its pathological counterpart PrPScrapie (PrP) is of great urgency. Here, we report the generation- and dose-dependent biological action of dense-shell poly(propylene imine) (PPI) glycodendrimers by using scrapie-infected neuroblastoma (ScN2a) cells and the real-time quaking-induced conversion assay (RT-QuIC) for validation of anti-prion efficiencies. Whereas the 2nd and 3rd generation of PPI glycodendrimers exhibited anti-prion conversion efficiency in ScN2a cells validated by RT-QuIC analysis, we observed that the 4th generation of glycodendrimers had shown no significant effect. Translational RT-QuIC studies conducted with human prions derived from sCJD patients indicated an anti-prion conversion effect (not on PrP degradation) of PPI glycodendrimers against human prions with the highest inhibitory activity of the 4th generation of PPI glycodendrimers towards prion aggregation compared to the 2nd and 3rd generation. In conclusion, our study highlights the potential of PPI glycodendrimers as therapeutic compounds due to their anti-conversion activity on human prions in a PrP strain depending manner.
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http://dx.doi.org/10.1007/s12035-019-01837-wDOI Listing
April 2020

Evaluation of Human Cerebrospinal Fluid Malate Dehydrogenase 1 as a Marker in Genetic Prion Disease Patients.

Biomolecules 2019 11 28;9(12). Epub 2019 Nov 28.

Department of Neurology, National Reference Center for CJD Surveillance University Medical Center Göttingen, 37075 Göttingen, Germany.

The exploration of accurate diagnostic markers for differential diagnosis of neurodegenerative diseases is an ongoing topic. A previous study on cerebrospinal fluid (CSF)-mitochondrial malate dehydrogenase 1 (MDH1) in sporadic Creutzfeldt-Jakob disease (sCJD) patients revealed a highly significant upregulation of MDH1. Here, we measured the CSF levels of MDH1 via enzyme-linked immunosorbent assay in a cohort of rare genetic prion disease cases, such as genetic CJD (gCJD) cases, exhibiting the E200K, V210I, P102L (Gerstmann-Sträussler-Scheinker syndrome (GSS)), or D178N (fatal familial insomnia (FFI)) mutations in the . Interestingly, we observed enhanced levels of CSF-MDH1 in all genetic prion disease patients compared to neurological controls (without neurodegeneration). While E200K and V210I carriers showed highest levels of MDH1 with diagnostic discrimination from controls of 0.87 and 0.85 area under the curve (AUC), FFI and GSS patients exhibited only moderately higher CSF-MDH1 levels than controls. An impact of the codon 129 methionine/valine (MV) genotype on the amount of MDH1 could be excluded. A correlation study of MDH1 levels with other neurodegenerative marker proteins revealed a significant positive correlation between CSF-MDH1 concentration with total tau (tau) but not with 14-3-3 in E200K, as well as in V210I patients. In conclusion, our study indicated the potential use of MDH1 as marker for gCJD patients which may complement the current panel of diagnostic biomarkers.
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http://dx.doi.org/10.3390/biom9120800DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6995564PMC
November 2019

Cerebrospinal fluid neurogranin as a new player in prion disease diagnosis and prognosis.

Neural Regen Res 2020 May;15(5):861-862

Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Ministry of Health; Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Spain; Department of Neurology, Clinical Dementia Center and National Reference Center for CJD Surveillance, University Medical School, Göttingen, Germany.

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http://dx.doi.org/10.4103/1673-5374.268901DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6990787PMC
May 2020

Cerebrospinal fluid non-phosphorylated tau in the differential diagnosis of Creutzfeldt-Jakob disease: a comparative prospective study with 14-3-3.

J Neurol 2020 Feb 7;267(2):543-550. Epub 2019 Nov 7.

Department of Neurology, Clinical Dementia Center and National Reference Center for CJD Surveillance, University Medical School, Göttingen, Germany.

Cerebrospinal fluid (CSF) non-phosphorylated tau (non-p-tau) is increased in sporadic Creutzfeldt-Jakob disease (CJD), but its accuracy in the differential diagnosis has not been previously established. Here, we first used a retrospective cohort of non-CJD (n = 135) and CJD (n = 137) cases to determine the optimal cutoff point for the discrimination of CJD cases. Next, we prospectively quantified non-p-tau and 14-3-3 protein in a cohort of 1427 cases received for CSF testing at the German National Reference Center for transmissible spongiform encephalopathies. Among them, 36 were subsequently diagnosed as CJD. The diagnostic accuracy of both proteins discriminating CJD cases was evaluated. Using a cutoff of 650 pg/mL, non-p-tau displayed 94.39% accuracy in discriminating CJD cases, while 92.92% accuracy was achieved by 14-3-3 using a cutoff of 20,000 AU/mL. Diagnostic test evaluation for both proteins showed a slightly better performance of non-p-tau compared to 14-3-3. The two biomarkers' concentrations showed a significant positive correlation, both in the total population and in CJD cases (p < 0.001). Finally, the analysis of CSF non-p-tau concentrations when undergoing pre-analytical factors showed high stability in front of temperature storage and freeze/thaw cycles. Therefore, we conclude that when used in the appropriate clinical context of a prion disease surveillance center, non-p-tau is a highly sensitive and specific diagnostic marker for CJD.
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http://dx.doi.org/10.1007/s00415-019-09610-8DOI Listing
February 2020

The cellular prion protein and its derived fragments in human prion diseases and their role as potential biomarkers.

Expert Rev Mol Diagn 2019 11 26;19(11):1007-1018. Epub 2019 Sep 26.

Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany.

: Human prion diseases are a heterogeneous group of incurable and debilitating conditions characterized by a progressive degeneration of the central nervous system. The conformational changes of the cellular prion protein and its formation into an abnormal isoform, spongiform degeneration, neuronal loss, and neuroinflammation are central to prion disease pathogenesis. It has been postulated that truncated variants of aggregation-prone proteins are implicated in neurodegenerative mechanisms. An increasing body of evidence indicates that proteolytic fragments and truncated variants of the prion protein are formed and accumulated in the brain of prion disease patients. These prion protein variants provide a high degree of relevance to disease pathology and diagnosis. : In the present review, we summarize the current knowledge on the occurrence of truncated prion protein species and their potential roles in pathophysiological states during prion diseases progression. In addition, we discuss their usability as a diagnostic biomarker in prion diseases. : Either as a primary factor in the formation of prion diseases or as a consequence from neuropathological affection, abnormal prion protein variants and fragments may provide independent information about mechanisms of prion conversion, pathological states, or disease progression.
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http://dx.doi.org/10.1080/14737159.2019.1667231DOI Listing
November 2019

Plasma YKL-40 in the spectrum of neurodegenerative dementia.

J Neuroinflammation 2019 Jul 12;16(1):145. Epub 2019 Jul 12.

Department of Neurology, Clinical Dementia Center and National Reference Center for CJD Surveillance, University Medical School, Robert Koch 40, 37075, Göttingen, Germany.

Background: Increased plasma YKL-40 has been reported in Alzheimer's disease (AD), but its levels in other neurodegenerative diseases are unknown. Here, we aimed to investigate plasma YKL-40 in the spectrum of neurodegenerative dementias.

Methods: YKL-40 was quantified in the plasma of 315 cases, including healthy controls (HC), neurological disease controls (ND), AD, vascular dementia (VaD), frontotemporal dementia (FTD), sporadic Creutzfeldt-Jakob disease (CJD) and Lewy body dementia (LBD). Diagnostic accuracy in the differential diagnostic context and influence of age and gender was assessed.

Results: Highest YKL-40 levels were detected in CJD, followed by LBD, VaD, AD, FTD, ND and HC. YKL-40 was associated to age but not to sex. After controlling for age, YKL-40 was significantly elevated in CJD compared to HC (p < 0.001), ND, AD and VaD (p < 0.01) and in LBD compared to HC (p < 0.05). In CJD, YKL-40 concentrations were significantly higher at late disease stages.

Conclusions: Plasma YKL-40 is significantly elevated in CJD regardless of clinical and genetic parameters, with moderate diagnostic accuracy in the discrimination from control cases. Our study discards a potential use of this biomarker in the differential diagnostic context but opens the possibility to be explored as a marker for CJD monitoring.
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http://dx.doi.org/10.1186/s12974-019-1531-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6624942PMC
July 2019

Cytosolic Trapping of a Mitochondrial Heat Shock Protein Is an Early Pathological Event in Synucleinopathies.

Cell Rep 2019 07;28(1):65-77.e6

Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center, Waldweg 33, Göttingen 37073, Germany; Institute of Neuroscience, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK; Max Planck Institute of Experimental Medicine, Hermann Rein Street 3, Göttingen 37075, Germany. Electronic address:

Alpha-synuclein (aSyn) accumulates in intracellular inclusions in synucleinopathies, but the molecular mechanisms leading to disease are unclear. We identify the 10 kDa heat shock protein (HSP10) as a mediator of aSyn-induced mitochondrial impairments in striatal synaptosomes. We find an age-associated increase in the cytosolic levels of HSP10, and a concomitant decrease in the mitochondrial levels, in aSyn transgenic mice. The levels of superoxide dismutase 2, a client of the HSP10/HSP60 folding complex, and synaptosomal spare respiratory capacity are also reduced. Overexpression of HSP10 ameliorates aSyn-associated mitochondrial dysfunction and delays aSyn pathology in vitro and in vivo. Altogether, our data indicate that increased levels of aSyn induce mitochondrial deficits, at least partially, by sequestering HSP10 in the cytosol and preventing it from acting in mitochondria. Importantly, these alterations manifest first at presynaptic terminals. Our study not only provides mechanistic insight into synucleinopathies but opens new avenues for targeting underlying cellular pathologies.
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http://dx.doi.org/10.1016/j.celrep.2019.06.009DOI Listing
July 2019

CSF neurogranin as a neuronal damage marker in CJD: a comparative study with AD.

J Neurol Neurosurg Psychiatry 2019 08 16;90(8):846-853. Epub 2019 May 16.

Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Ministry of Health, L'Hospilatet del Llobregat, Barcelona, Spain

Objective: To investigate whether cerebrospinal fluid (CSF) neurogranin concentrations are altered in sporadic Creutzfeldt-Jakob disease (CJD), comparatively with Alzheimer's disease (AD), and associated with neuronal degeneration in brain tissue.

Methods: CSF neurogranin, total tau, neurofilament light (NFL) and 14-3-3 protein were measured in neurological controls (NCs, n=64), AD (n=46) and CJD (n=81). The accuracy of neurogranin discriminating the three diagnostic groups was evaluated. Correlations between neurogranin and neurodegeneration biomarkers, demographic, genetic and clinical data were assessed. Additionally, neurogranin expression in postmortem brain tissue was studied.

Results: Compared with NC, CSF neurogranin concentrations were increased in CJD (4.75 times of NC; p<0.001, area under curve (AUC), 0.96 (95% CI 0.93 to 0.99) and AD (1.94 times of NC; p<0.01, AUC 0.73, 95% CI 0.62 to 0.82), and were able to differentiate CJD from AD (p<0.001, AUC 0.85, 95% CI 0.78 to 0.92). CSF tau was increased in CJD (41 times of NC) and in AD (3.1 times of NC), both at p<0.001. In CJD, neurogranin positively correlated with tau (r=0.55, p<0.001) and was higher in 14-3-3-positivity (p<0.05), but showed no association with NFL (r=0.08, p=0.46). CJD-MM1/MV1 cases displayed higher neurogranin levels than VV2 cases. Neurogranin was increased at early CJD disease stages and was a good prognostic marker of survival time in CJD. In brain tissue, neurogranin was detected in the cytoplasm, membrane and postsynaptic density fractions of neurons, with reduced levels in AD, and more significantly in CJD, where they correlated with synaptic and axonal markers.

Conclusions: Neurogranin is a new biomarker of prion pathogenesis with diagnostic and prognostic abilities, which reflects the degree of neuronal damage in brain tissue in a CJD subtype manner.
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http://dx.doi.org/10.1136/jnnp-2018-320155DOI Listing
August 2019

Seeding variability of different alpha synuclein strains in synucleinopathies.

Ann Neurol 2019 05 27;85(5):691-703. Epub 2019 Mar 27.

Department of Neurology, University Medicine Goettingen and the German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.

Objectives: Currently, the exact reasons why different α-synucleinopathies exhibit variable pathologies and phenotypes are still unknown. A potential explanation may be the existence of distinctive α-synuclein conformers or strains. Here, we intend to analyze the seeding activity of dementia with Lewy bodies (DLB) and Parkinson's disease (PD) brain-derived α-synuclein seeds by real-time quaking-induced conversion (RT-QuIC) and to investigate the structure and morphology of the α-synuclein aggregates generated by RT-QuIC.

Methods: A misfolded α-synuclein-enriched brain fraction from frontal cortex and substantia nigra pars compacta tissue, isolated by several filtration and centrifugation steps, was subjected to α-synuclein/RT-QuIC analysis. Our study included neuropathologically well-characterized cases with DLB, PD, and controls (Ctrl). Biochemical and morphological analyses of RT-QuIC products were conducted by western blot, dot blot analysis, Raman spectroscopy, atomic force microscopy, and transmission electron microscopy.

Results: Independently from the brain region, we observed different seeding kinetics of α-synuclein in the RT-QuIC in patients with DLB compared to PD and Ctrl. Biochemical characterization of the RT-QuIC product indicated the generation of a proteinase K-resistant and fibrillary α-synuclein species in DLB-seeded reactions, whereas PD and control seeds failed in the conversion of wild-type α-synuclein substrate.

Interpretation: Structural variances of α-synuclein seeding kinetics and products in DLB and PD indicated, for the first time, the existence of different α-synuclein strains in these groups. Therefore, our study contributes to a better understanding of the clinical heterogeneity among α-synucleinopathies, offers an opportunity for a specific diagnosis, and opens new avenues for the future development of strain-specific therapies. Ann Neurol 2019;85:691-703.
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http://dx.doi.org/10.1002/ana.25446DOI Listing
May 2019

Cerebrospinal fluid neurofilament light in suspected sporadic Creutzfeldt-Jakob disease.

J Clin Neurosci 2019 Feb 9;60:124-127. Epub 2018 Oct 9.

Department of Neurology, University Medical School, Göttingen, Germany; Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Ministry of Health, L'Hospitalet de Llobregat, Spain; Bellvitge Biomedical Research Institute (IDBELL), L'Hospitalet de Llobregat, Spain. Electronic address:

Sporadic Creutzfeldt-Jakob disease (sCJD) is the most common form of human prion disease. It is invariably fatal and displays a short clinical disease stage. The key event in sCJD is the propagation of a beta-sheet rich conformer of the physiological PrP protein, known as PrP. Neuropathological disease characteristics include gliosis, neuronal loss and spongiform degeneration; disease clinical manifestations refer to mental and visual disabilities, cognitive impairment, gait or limb ataxia, myoclonus and mutism. Definite sCJD diagnosis requires post-mortem brain material histopathological examination. However, highly certain pre-mortem differential diagnosis is desired to exclude other treatable disorders and to reduce disease transmission risks. Detection and/or quantification of cerebrospinal fluid (CSF) biomarkers reflecting neuronal damage and PrP misfolding in the diseased brain significantly enhance pre-mortem diagnosis. Previously established and newly identified biomarkers are used towards this direction. Increased CSF Neurofilament light chain (NFL) concentrations have been reported in several neurological disorders, including prion diseases. In the present study, we analyzed CSF NFL levels in two independent patient cohorts, consisting of highly suspected sCJD cases that were further classified as sCJD or non-CJD according to established diagnostic criteria. CSF NFL concentrations were increased in sCJD compared to non-CJD cases in both cohorts (area under the curve (with 95% confidence interval) equal to 0.89 (0.82 to 0.97) and 0.86 (0.77 to 0.96), respectively. CSF NFL was associated neither to age nor to sex but correlated with total-tau concentrations in both cohorts. Overall, our data provide independent validation of CSF NFL utility in sCJD differential diagnosis.
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http://dx.doi.org/10.1016/j.jocn.2018.09.031DOI Listing
February 2019

Interlaboratory validation of cerebrospinal fluid α-synuclein quantification in the diagnosis of sporadic Creutzfeldt-Jakob disease.

Alzheimers Dement (Amst) 2018 7;10:461-470. Epub 2018 Jul 7.

Department of Neurology, University Medicine Göttingen, Göttingen, Germany.

Introduction: Cerebrospinal fluid α-synuclein level is increased in sporadic Creutzfeldt-Jakob disease cases. However, the clinical value of this biomarker remains to be established. In this study, we have addressed the clinical validation parameters and the interlaboratory reproducibility by using an electrochemiluminescent assay.

Methods: Cerebrospinal fluid α-synuclein was quantified in a total of 188 sporadic Creutzfeldt-Jakob disease and non-Creutzfeldt-Jakob-disease cases to determine sensitivity and specificity values and lot-to-lot variability. Two round robin tests with 70 additional cases were performed in six independent laboratories.

Results: A sensitivity of 93% and a specificity of 96% were achieved in discriminating sporadic Creutzfeldt-Jakob disease. No differences were detected between lots. The mean interlaboratory coefficient of variation was 23%, and the intralaboratory coefficient of variations ranged 2.70%-11.39%. Overall, 97% of samples were correctly diagnosed.

Discussion: The herein validated α-synuclein assay is robust, accurate, and reproducible in identifying Creutzfeldt-Jakob disease cases. Thus, it is ready for implementation in the clinical practice to support the diagnosis of Creutzfeldt-Jakob disease.
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http://dx.doi.org/10.1016/j.dadm.2018.06.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6171371PMC
July 2018

Nuclear localization and phosphorylation modulate pathological effects of alpha-synuclein.

Hum Mol Genet 2019 01;28(1):31-50

Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany.

Alpha-synuclein (aSyn) is a central player in Parkinson's disease (PD) but the precise molecular mechanisms underlying its pathogenicity remain unclear. It has recently been suggested that nuclear aSyn may modulate gene expression, possibly via interactions with DNA. However, the biological behavior of aSyn in the nucleus and the factors affecting its transcriptional role are not known. Here, we investigated the mechanisms underlying aSyn-mediated transcription deregulation by assessing its effects in the nucleus and the impact of phosphorylation in these dynamics. We found that aSyn induced severe transcriptional deregulation, including the downregulation of important cell cycle-related genes. Importantly, transcriptional deregulation was concomitant with reduced binding of aSyn to DNA. By forcing the nuclear presence of aSyn in the nucleus (aSyn-NLS), we found the accumulation of high molecular weight aSyn species altered gene expression and reduced toxicity when compared with the wild-type or exclusively cytosolic protein. Interestingly, nuclear localization of aSyn, and the effect on gene expression and cytotoxicity, was also modulated by phosphorylation on serine 129. Thus, we hypothesize that the role of aSyn on gene expression and, ultimately, toxicity, may be modulated by the phosphorylation status and nuclear presence of different aSyn species. Our findings shed new light onto the subcellular dynamics of aSyn and unveil an intricate interplay between subcellular location, phosphorylation and toxicity, opening novel avenues for the design of future strategies for therapeutic intervention in PD and other synucleinopathies.
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http://dx.doi.org/10.1093/hmg/ddy326DOI Listing
January 2019

Cerebrospinal Fluid Total and Phosphorylated α-Synuclein in Patients with Creutzfeldt-Jakob Disease and Synucleinopathy.

Mol Neurobiol 2019 May 22;56(5):3476-3483. Epub 2018 Aug 22.

Department of Neurology, University Medical Center Goettingen, Goettingen, Germany.

High levels of total α-synuclein (t-α-synuclein) in the cerebrospinal fluid (CSF) were reported in sporadic Creutzfeldt-Jakob disease (sCJD). The potential use of t-α-synuclein in the discrimination of Lewy body dementias (i.e., Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB)) is still under investigation. In addition, phospho-serine-129 α-synuclein (p-α-synuclein) has been described to be slightly increased in the CSF of synucleinopathies. Here, we analyzed t-α-synuclein and p-α-synuclein concentrations and their ratio in the context of differential diagnosis of neurodegenerative diseases. We quantified the levels of CSF t-α-synuclein and p-α-synuclein in a cohort of samples composed of neurological controls (NC), sCJD, PDD, and DLB by means of newly developed specific enzyme-linked immunosorbent assays. T-α-synuclein and p-α-synuclein were specifically elevated in sCJD compared to other disease groups. The area under the curve (AUC) values for t-α-synuclein were higher for the discrimination of sCJD from dementias associated to Lewy bodies as compared to the use of p-α-synuclein. A combination of both markers even increased the diagnostic accuracy. An inverse correlation was observed in CSF between t-α-synuclein and p-α-synuclein, especially in the DLB group, indicating a disease-relevant association between both markers. In conclusion, our data confirm t-α-synuclein and p-α-synuclein as robust biomarkers for sCJD and indicate the potential use of colorimetric t-α-synuclein ELISAs for differential diagnosis of dementia types.
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http://dx.doi.org/10.1007/s12035-018-1313-4DOI Listing
May 2019

Membrane binding, internalization, and sorting of alpha-synuclein in the cell.

Acta Neuropathol Commun 2018 08 14;6(1):79. Epub 2018 Aug 14.

Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Goettingen, 37073, Göttingen, Germany.

Alpha-synuclein (aSyn) plays a crucial role in Parkinson's disease (PD) and other synucleinopathies, since it misfolds and accumulates in typical proteinaceous inclusions. While the function of aSyn is thought to be related to vesicle binding and trafficking, the precise molecular mechanisms linking aSyn with synucleinopathies are still obscure. aSyn can spread in a prion-like manner between interconnected neurons, contributing to the propagation of the pathology and to the progressive nature of synucleinopathies. Here, we investigated the interaction of aSyn with membranes and trafficking machinery pathways using cellular models of PD that are amenable to detailed molecular analyses. We found that different species of aSyn can enter cells and form high molecular weight species, and that membrane binding properties are important for the internalization of aSyn. Once internalized, aSyn accumulates in intracellular inclusions. Interestingly, we found that internalization is blocked in the presence of dynamin inhibitors (blocked membrane scission), suggesting the involvement of the endocytic pathway in the internalization of aSyn. By screening a pool of small Rab-GTPase proteins (Rabs) which regulate membrane trafficking, we found that internalized aSyn partially colocalized with Rab5A and Rab7. Initially, aSyn accumulated in Rab4A-labelled vesicles and, at later stages, it reached the autophagy-lysosomal pathway (ALP) where it gets degraded. In total, our study emphasizes the importance of membrane binding, not only as part of the normal function but also as an important step in the internalization and subsequent accumulation of aSyn. Importantly, we identified a fundamental role for Rab proteins in the modulation of aSyn processing, clearance and spreading, suggesting that targeting Rab proteins may hold important therapeutic value in PD and other synucleinopathies.
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http://dx.doi.org/10.1186/s40478-018-0578-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6090819PMC
August 2018

Cerebrospinal Fluid Total Prion Protein in the Spectrum of Prion Diseases.

Mol Neurobiol 2019 Apr 30;56(4):2811-2821. Epub 2018 Jul 30.

Department of Neurology, University Medical School, Göttingen, Germany.

Cerebrospinal fluid (CSF) total prion protein (t-PrP) is decreased in sporadic Creutzfeldt-Jakob disease (sCJD). However, data on the comparative signatures of t-PrP across the spectrum of prion diseases, longitudinal changes during disease progression, and levels in pre-clinical cases are scarce. T-PrP was quantified in neurological diseases (ND, n = 147) and in prion diseases from different aetiologies including sporadic (sCJD, n = 193), iatrogenic (iCJD, n = 12) and genetic (n = 209) forms. T-PrP was also measured in serial lumbar punctures obtained from sCJD cases at different symptomatic disease stages, and in asymptomatic prion protein gene (PRNP) mutation carriers. Compared to ND, t-PrP concentrations were significantly decreased in sCJD, iCJD and in genetic prion diseases associated with the three most common mutations E200K, V210I (associated with genetic CJD) and D178N-129M (associated with fatal familial insomnia). In contrast, t-PrP concentrations in P102L mutants (associated with the Gerstmann-Sträussler-Scheinker syndrome) remained unaltered. In serial lumbar punctures obtained at different disease stages of sCJD patients, t-PrP concentrations inversely correlated with disease progression. Decreased mean t-PrP values were detected in asymptomatic D178-129M mutant carriers, but not in E200K and P102L carriers. The presence of low CSF t-PrP is common to all types of prion diseases regardless of their aetiology albeit with mutation-specific exceptions in a minority of genetic cases. In some genetic prion disease, decreased levels are already detected at pre-clinical stages and diminish in parallel with disease progression. Our data indicate that CSF t-PrP concentrations may have a role as a pre-clinical or early symptomatic diagnostic biomarker in prion diseases as well as in the evaluation of therapeutic interventions.
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http://dx.doi.org/10.1007/s12035-018-1251-1DOI Listing
April 2019

Cerebrospinal Fluid Prion Disease Biomarkers in Pre-clinical and Clinical Naturally Occurring Scrapie.

Mol Neurobiol 2018 Nov 23;55(11):8586-8591. Epub 2018 Mar 23.

Department of Neurology, University Medical Center, Göttingen, Germany.

The analysis of the cerebrospinal fluid (CSF) biomarkers in patients with suspected prion diseases became a useful tool in diagnostic routine. Prion diseases can only be identified at clinical stages when the disease already spread throughout the brain and massive neuronal damage occurs. Consequently, the accuracy of CSF tests detecting non-symptomatic patients is unknown. Here, we aimed to investigate the usefulness of CSF-based diagnostic tests in pre-clinical and clinical naturally occurring scrapie. While decreased total prion protein (PrP) levels and positive PrP seeding activity were already detectable at pre-symptomatic stages, the surrogate markers of neuronal damage total tau (tau) and 14-3-3 proteins were exclusively increased at clinical stages. The present findings confirm that alterations in PrP levels and conformation are primary events in the pathology of prion diseases preceding neuronal damage. Our work also supports the potential use of these tests in the screening of pre-symptomatic scrapie and human prion disease cases.
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http://dx.doi.org/10.1007/s12035-018-1014-zDOI Listing
November 2018

Molecular and Clinical Aspects of Protein Aggregation Assays in Neurodegenerative Diseases.

Mol Neurobiol 2018 Sep 10;55(9):7588-7605. Epub 2018 Feb 10.

Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases, Robert-Koch-Str. 40, 37075, Göttingen, Germany.

The presence of protein deposits is a common pathological hallmark in patients suffering from neurodegenerative conditions and other proteinopathies. Deciphering the molecular basis of protein misfolding and aggregation is a crucial step towards the full comprehension of the factors that trigger the onset of these diseases and for the development of efficient therapeutical strategies. In this regard, in vitro aggregation assays for misfolded proteins offer an excellent tool to study pathological processes of protein deposition under controlled conditions, where confounders can be easily discriminated. These methods are generally cost-effective and have been proved useful in many fields, including drug discovery and clinical diagnostics. Here, we review the bases of in vitro aggregation and seeding assays, recapitulate their main applications and offer a critical evaluation of their limitations. Comprehending the molecular mechanisms behind these assays and combining them with in vivo or cell-based experiments will maximize their potential and allow the necessary improvement to overcome some of the current drawbacks.
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http://dx.doi.org/10.1007/s12035-018-0926-yDOI Listing
September 2018

Cerebrospinal fluid neurofilament light levels in neurodegenerative dementia: Evaluation of diagnostic accuracy in the differential diagnosis of prion diseases.

Alzheimers Dement 2018 06 3;14(6):751-763. Epub 2018 Feb 3.

Network Center for Biomedical Research in Neurodegenerative Diseases, (CIBERNED), Institute Carlos III, Ministry of Health, Hospitalet de Llobregat, Barcelona, Spain. Electronic address:

Introduction: Neurofilament light (NFL) levels in the cerebrospinal fluid are increased in several neurodegenerative dementias. However, their diagnostic accuracy in the differential diagnostic context is unknown.

Methods: Cerebrospinal fluid NFL levels were quantified in nonprimarily neurodegenerative neurological and psychiatric diseases (n = 122), mild cognitive impairment (n = 48), Alzheimer's disease (n = 108), dementia with Lewy bodies/Parkinson's disease dementia (n = 53), vascular dementia (n = 46), frontotemporal dementia (n = 41), sporadic Creutzfeldt-Jakob disease (sCJD, n = 132), and genetic prion diseases (n = 182).

Results: The highest NFL levels were detected in sCJD, followed by vascular dementia, frontotemporal dementia, dementia with Lewy bodies/Parkinson's disease dementia, Alzheimer's disease, and mild cognitive impairment. In sCJD, NFL levels correlated with cerebrospinal fluid tau and disease duration. NFL levels were able to differentiate sCJD from nonprimarily neurodegenerative neurological and psychiatric diseases (area under the curve = 0.99, 95% confidence interval: 0.99-1) and from the other diagnostic groups showing cognitive impairment/dementia of a non-CJD etiology (area under the curve = 0.90, 95% confidence interval: 0.87-0.92). Compared to nonprimarily neurodegenerative neurological and psychiatric diseases, NFL was also elevated in genetic prion diseases associated with the E200K, V210I, P102L, and D178N prion protein gene mutations.

Discussion: Increased NFL levels are a common feature in neurodegenerative dementias.
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http://dx.doi.org/10.1016/j.jalz.2017.12.008DOI Listing
June 2018

Applications of the real-time quaking-induced conversion assay in diagnosis, prion strain-typing, drug pre-screening and other amyloidopathies.

Expert Rev Mol Diagn 2017 10 8;17(10):897-904. Epub 2017 Sep 8.

a Department of Neurology , University Medical Center Göttingen and the German Center for Neurodegenerative Diseases (DZNE) , Göttingen , Germany.

Introduction: The development of in vitro protein misfolding amplification assays for the detection and analysis of abnormally folded proteins, such as proteinase K resistant prion protein (PrP) was a major innovation in the prion field. In prion diseases, these types of assays imitate the pathological conversion of the cellular PrP (PrP) into a proteinase resistant associated conformer or amyloid, called PrP. Areas covered: The most prominent protein misfolding amplification assays are the protein misfolding cyclic amplification (PMCA), which is based on sonication and the real-time quaking-induced conversion (RT-QuIC) technique based on shaking. The more recently established RT-QuIC is fully automatic and enables the monitoring of misfolded protein aggregates in real-time by using a fluorescent dye. Expert commentary: RT-QuIC is a very robust and highly reproducible test system which is applicable in diagnosis, prion strain-typing, drug pre-screening and other amyloidopathies.
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http://dx.doi.org/10.1080/14737159.2017.1368389DOI Listing
October 2017

Copper(II) and the pathological H50Q α-synuclein mutant: Environment meets genetics.

Commun Integr Biol 2017 6;10(1):e1270484. Epub 2017 Feb 6.

Department of Neurodegeneration and Restorative Research, University Medical Centre Göttingen, Göttingen, Germany; Max Planck Institute for Experimental Medicine, Göttingen, Germany.

Copper is one of the metals described to bind the Parkinson disease-related protein α-synuclein (aSyn), and to promote its aggregation. Although histidine at position 50 in the aSyn sequence is one of the most studied copper-anchoring sites, its precise role in copper binding and aSyn aggregation is still unclear. Previous studies suggested that this residue does not significantly affect copper-mediated aSyn aggregation. However, our findings showed that the aggregation of the pathological H50Q aSyn mutant is enhanced by copper hints otherwise. Despite the inexistence of a model for aSyn H50Q-copper complexation, we discuss possible mechanisms by which this metal contributes to the misfolding and self-assembly of this particular aSyn mutant. Considering the genetic association of the H50Q mutation with familial forms of Parkinson disease, and the fact that copper homeostasis is deregulated in this disorder, understanding the interplay between both factors will shed light into the molecular and cellular mechanisms triggering the development and spreading of the aSyn pathology.
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http://dx.doi.org/10.1080/19420889.2016.1270484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5333520PMC
February 2017

Environmental and genetic factors support the dissociation between α-synuclein aggregation and toxicity.

Proc Natl Acad Sci U S A 2016 10 5;113(42):E6506-E6515. Epub 2016 Oct 5.

Department of Neurodegeneration and Restorative Research, University Medical Centre Göttingen, 37073 Goettingen, Germany; Max Planck Institute for Experimental Medicine, Goettingen, Germany

Synucleinopathies are a group of progressive disorders characterized by the abnormal aggregation and accumulation of α-synuclein (aSyn), an abundant neuronal protein that can adopt different conformations and biological properties. Recently, aSyn pathology was shown to spread between neurons in a prion-like manner. Proteins like aSyn that exhibit self-propagating capacity appear to be able to adopt different stable conformational states, known as protein strains, which can be modulated both by environmental and by protein-intrinsic factors. Here, we analyzed these factors and found that the unique combination of the neurodegeneration-related metal copper and the pathological H50Q aSyn mutation induces a significant alteration in the aggregation properties of aSyn. We compared the aggregation of WT and H50Q aSyn with and without copper, and assessed the effects of the resultant protein species when applied to primary neuronal cultures. The presence of copper induces the formation of structurally different and less-damaging aSyn aggregates. Interestingly, these aggregates exhibit a stronger capacity to induce aSyn inclusion formation in recipient cells, which demonstrates that the structural features of aSyn species determine their effect in neuronal cells and supports a lack of correlation between toxicity and inclusion formation. In total, our study provides strong support in favor of the hypothesis that protein aggregation is not a primary cause of cytotoxicity.
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http://dx.doi.org/10.1073/pnas.1606791113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5081623PMC
October 2016

In vivo amyloid aggregation kinetics tracked by time-lapse confocal microscopy in real-time.

Biotechnol J 2016 Jan 5;11(1):172-7. Epub 2016 Jan 5.

Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain.

Amyloid polymerization underlies an increasing number of human diseases. Despite this process having been studied extensively in vitro, aggregation is a difficult process to track in vivo due to methodological limitations and the slow kinetics of aggregation reactions in cells and tissues. Herein we exploit the amyloid properties of the inclusions bodies (IBs) formed by amyloidogenic proteins in bacteria to address the kinetics of in vivo amyloid aggregation. To this aim we used time-lapse confocal microscopy and a fusion of the amyloid-beta peptide (A β42) with a fluorescent reporter. This strategy allowed us to follow the intracellular kinetics of amyloid-like aggregation in real-time and to discriminate between variants exhibiting different in vivo aggregation propensity. Overall, the approach opens the possibility to assess the impact of point mutations as well as potential anti-aggregation drugs in the process of amyloid formation in living cells.
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http://dx.doi.org/10.1002/biot.201500252DOI Listing
January 2016