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Clayton E.L.,University College London | Mizielinska S.,University College London | Edgar J.R.,University of Cambridge | Nielsen T.T.,Copenhagen University | And 11 more authors.
Acta Neuropathologica

Mutations in the charged multivesicular body protein 2B (CHMP2B) cause frontotemporal dementia (FTD). We report that mice which express FTD-causative mutant CHMP2B at physiological levels develop a novel lysosomal storage pathology characterised by large neuronal autofluorescent aggregates. The aggregates are an early and progressive pathology that occur at 3 months of age and increase in both size and number over time. These autofluorescent aggregates are not observed in mice expressing wild-type CHMP2B, or in non-transgenic controls, indicating that they are a specific pathology caused by mutant CHMP2B. Ultrastructural analysis and immuno-gold labelling confirmed that they are derived from the endolysosomal system. Consistent with these findings, CHMP2B mutation patient brains contain morphologically similar autofluorescent aggregates. These aggregates occur significantly more frequently in human CHMP2B mutation brain than in neurodegenerative disease or age-matched control brains. These data suggest that lysosomal storage pathology is the major neuronal pathology in FTD caused by CHMP2B mutation. Recent evidence suggests that two other genes associated with FTD, GRN and TMEM106B are important for lysosomal function. Our identification of lysosomal storage pathology in FTD caused by CHMP2B mutation now provides evidence that endolysosomal dysfunction is a major degenerative pathway in FTD. © 2015 The Author(s) Source

Blechingberg J.,University of Aarhus | Holm I.E.,Laboratory for Experimental Neuropathology | Nielsen A.L.,University of Aarhus

The FET protein family consists of FUS (TLS), EWS (EWSR1), and TAF15. The FET proteins bind DNA and RNA and are involved in transcriptional regulation and RNA processing. Translocations involving the FET genes have been identified in human sarcomas, and mutations in the FUS and TAF15 genes are associated with Amyotrophic Lateral Sclerosis. We here describe the characterization of the porcine FET proteins and an expression analysis during embryonic brain development. The FET proteins are well conserved between pig and human. FET protein mutations associated with Amyotrophic Lateral Sclerosis affect evolutionary conserved amino acids. In cultured cells the porcine FET proteins have a nuclear localization with some specific cytoplasmic aggregation of TAF15 in neuronal progenitor cells. Immunohistochemical analyses supported a predominant nuclear localization, but also faint cytoplasmic localization. The FET proteins have similar expression profiles throughout the development of the embryonic porcine brain and most cell types appeared positive for expression. Quantitative RT-PCR analyses showed that the FET mRNA expression decreased during embryonic development of hippocampus and for FUS and EWS during embryonic development of cortex. FET mRNA expression was relatively constant in brain stem, basal ganglia, and cerebellum. Overall the FET protein localization and mRNA and protein expression analyses were concordant with previous analysis from the human brain. The presented results indicate that the porcine brain could be an alternative model for the future examination of the normal functions as well as neurological disease associated functions of the FET proteins. © 2011 Elsevier B.V. Source

Veno M.T.,University of Aarhus | Bramsen J.B.,University of Aarhus | Bendixen C.,University of Aarhus | Panitz F.,University of Aarhus | And 3 more authors.
RNA Biology

Editing by ADAR enzymes is essential for mammalian life. Still, knowledge of the spatio-temporal editing patterns in mammals is limited. By use of 454 amplicon sequencing we examined the editing status of 12 regionally extracted mRNAs from porcine developing brain encompassing a total of 64 ADAR editing sites. In total 24 brain tissues, dissected from up to five regions from embryonic gestation day 23, 42, 60, 80, 100 and 115, were examined for editing. Generally, editing increased during embryonic development concomitantly with an increase in ADAR2 mRNA level. Notably, the Gria2 (GluR-B) Q/R site, reported to be ~100% edited in previous studies, is only 54% edited at embryonic day 23. Transcripts with multiple editing sites in close proximity to each other exhibit coupled editing and an extraordinary incidence of long-range coupling of editing events more than 32 kb apart is observed for the kainate glutamate receptor 2 transcript, Grik2. Our study reveals complex spatio-temporal ADAR editing patterns of coordinated editing events that may play important roles in the development of the mammalian brain. © 2012 Landes Bioscience. Source

Brinkmann C.R.,University of Aarhus | Jensen L.,University of Aarhus | Dagnaes-Hansen F.,University of Aarhus | Holm I.E.,University of Aarhus | And 6 more authors.
Journal of Biological Chemistry

Mitochondria, the powerhouses of our cells, are remnants of a eubacterial endosymbiont. Notwithstanding the evolutionary time that has passed since the initial endosymbiotic event, mitochondria have retained many hallmarks of their eubacterial origin. Recent studies have indicated that during perturbations of normal homeostasis, such as following acute trauma leading to massive necrosis and release of mitochondria, the immune system might mistake symbiont for enemy and initiate an inappropriate immune response. The innate immune system is the first line of defense against invading microbial pathogens, and as such is the primary suspect in the recognition of mitochondriaderived danger-associated molecular patterns and initiation of an aberrant response. Conversely, innate immune mechanisms are also central to noninflammatory clearance of innocuous agents. Here we investigated the role of a central humoral component of innate immunity, the lectin pathway of complement, in recognition of mitochondria in vitro and in vivo. We found that the soluble pattern recognition molecules, mannan-binding lectin (MBL), L-ficolin, and M-ficolin, were able to recognize mitochondria. Furthermore,MBLin complex with MBL-associated serine protease 2 (MASP-2) was able to activate the lectin pathway and deposit C4 onto mitochondria, suggesting that these molecules are involved either in homeostatic clearance of mitochondria or in induction of untoward inflammatory reactions. Wefound that following mitochondrial challenge, C3 was consumed in vivo in the absence of overt inflammation, indicating a potential role of complement in noninflammatory clearance of mitochondria. Thus, we report here the first indication of involvement of the lectin pathway in mitochondrial immune handling. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc. Source

Sondergaard L.V.,University of Aarhus | Herskin M.S.,University of Aarhus | Ladewig J.,Copenhagen University | Holm I.E.,Laboratory for Experimental Neuropathology | And 2 more authors.
Applied Animal Behaviour Science

The number of animals used in research should be limited as much as possible. Among cloned animals, genetic variation is minimal and to the extent that behaviour is genetically determined inter-individual variability is expected to be higher among naturally bred animals. However, the cloning procedure per se might affect the resultant phenotype leading to phenotypic variations independent of the genetic background. Recently, cloned Göttingen minipigs carrying a mutation for Alzheimer's disease have been produced. In order to document the development of Alzheimer's disease symptoms, these pigs were subjected to a behavioural test of memory, the spontaneous object recognition test, from an early age. At ages 1 and 2 years no evidence of memory decline was found, yet the data showed striking behavioural variability among the cloned groups. The aim of the present study was to investigate effects of genetic homogeneity on variability of cloned minipigs compared with non-cloned controls regarding behavioural variables in a cognitive test, namely the spontaneous object recognition test.Significant differences in the variability between the cloned and control pigs were found in five out of 24 behavioural variables. The clones showed lower variability for four of the measures, whereas the variability was increased for one variable. No significant difference between the cloned and the control group was found for the remaining 19 variables (79%). In 14 of these, the standard deviation was numerically greater for the control group compared to the cloned group, indicating that variation may be less in cloned animals, but not demonstrable with the small group size of the present study (n=6 for each of the two groups tested).Overall, this study failed to show unambiguously that variability in these behavioural variables in cloned minipigs is less than in naturally bred control subjects and therefore does not directly support the hypothesis that cloning may be used to replicate animals in order to reduce group size in experimentation animals. © 2012 Elsevier B.V. Source

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