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Authors: Madsen, Jes Buster | Folke, Jonas | Pakkenberg, Bente

Article Type: Research Article

Abstract: We estimated by stereological methods the neocortical volume occupied by plaques and tangles in females dying with severe Alzheimer’s disease (AD), age-matched female subjects with severe vascular dementia (VaD), and normal control brains. Stereological investigations include a uniform sampling of the tissue in the whole of neocortex and its subdivisions. Resultant volume estimates provide information about the overall burden of these two pathological changes and their volume fractions and allow for correlational studies between the pathological changes and factors such as the total neocortical neuronal cell numbers, dementia test scores, and age. We estimated the volume of plaques and tangles …in the entire neocortex and frontal-, temporal-, parietal-, and occipital cortex in nine female AD brains, four female patients dying with VaD, and six neurologically normal female control brains using point-counting in uniform samples of neocortex. The volume occupied by plaques comprised approximately 1% of neocortex, while the neocortical tangles made up approximately 0.1% of neocortex of AD patients but were scarcely present in the other study groups. The individual tangle and plaque volumes did not correlate to the ultimate dementia score of the AD subjects, despite correlating with reduced neocortical volume. In neocortex of AD patients, the burden of plaques and tangles is much higher than that in patients with severe vascular dementia or normal older women but only occupy a small fraction of the neocortical volume. Show more

Keywords: Neurofibrillary tangles, quantification, senile plaques, stereology, volume fraction

DOI: 10.3233/JAD-180105

Citation: Journal of Alzheimer's Disease, vol. 64, no. 3, pp. 723-734, 2018

Authors: Folke, Jonas | Arkan, Sertan | Martinsson, Isak | Aznar, Susana | Gouras, Gunnar | Brudek, Tomasz | Hansen, Christian

Article Type: Research Article

Abstract: Background: α-synuclein (α-syn) aggregation contributes to the progression of multiple neurodegenerative diseases. We recently found that the isoform b of the co-chaperone DNAJB6 is a strong suppressor of α-syn aggregation in vivo and in vitro . However, nothing is known about the role of the endogenous isoform b of DNAJB6 (DNAJB6b) in health and disease, due to lack of specific antibodies. Objective: Here we generated a novel anti-DNAJB6b antibody to analyze the localization and expression of this isoform in cells, in tissue and in clinical material. Methods: To address this we used immunocytochemistry, immunohistochemistry, as well as a novel quantitative …DNAJB6 specific ELISA method. Results: The endogenous protein is mainly expressed in the cytoplasm and in neurites in vitro , where it is found more in dendrites than in axons. We further verified in vivo that DNAJB6b is expressed in the dopaminergic neurons of the substantia nigra pars compacta (SNpc ), which is a neuronal subpopulation highly sensitive to α-syn aggregation, that degenerate to a large extend in patients with Parkinson’s disease (PD) and multiple system atrophy (MSA). When we analyzed the expression levels of DNAJB6b in brain material from PD and MSA patients, we found a downregulation of DNAJB6b by use of ELISA based quantification. Interestingly, this was also true when analyzing tissue from patients with progressive supranuclear palsy, a taupathic atypical parkinsonian disorder. However, the total level of DNAJB6 was upregulated in these three diseases, which may indicate an upregulation of the other major isoform of DNAJB6, DNAJB6a. Conclusion: This study shows that DNAJB6b is downregulated in several different neurodegenerative diseases, which makes it an interesting target to further investigate in relation to amyloid protein aggregation and disease progression. Show more

Keywords: Alpha-synuclein, clinical samples, DNAJB6, neurodegeneration, synucleinopathy

DOI: 10.3233/JPD-202512

Citation: Journal of Parkinson's Disease, vol. 11, no. 4, pp. 1791-1803, 2021