A: Pathogenic mechanisms最新文献

{"title":"A04 Circhtt, a circular rna from the huntington’s disease gene locus: functional characterization and possible implications for disease modulation","authors":"J. Döring, S. Ferrari, A. Monziani, Claudio Oss Pegorar, T. Tripathi, F. Leva, E. Kerschbamer, Virginia B. Mattis, C. Dieterich, E. Dassi, V. Wheeler, H. Hansíková, Z. Ellederová, J. Wilusz, M. Biagioli","doi":"10.1136/jnnp-2021-ehdn.4","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.4","url":null,"abstract":"Background Circular RNAs (circRNAs) are a special group of non-coding RNAs formed by back-splicing. Mostly cytosolic in eukaryotic cells, circRNAs are particularly enriched and conserved in neurons and originate from protein-coding genes to function as global regulators of gene expression. Recent studies showed that circRNAs partake in brain physiology and pathology, contributing to neurological disorders, such as myotonic dystrophy type 1, Parkinson’s and Alzheimer’s Diseases. Here, we identified the first ever known brain enriched RNA circle originating from the Huntington’s Disease gene HTT (CircHTT: 484 nt, Ex 2-6, chr4:3088665-3109150) which is conserved in mouse and minipig. Aims and Methods To functionally characterize circHTT and its implication for HD pathogenesis, we first studied its expression pattern in human and mouse body districts and in iPS-derived neuronal cell lines with different CAG repeats. Then, overexpression and down-regulation of the circle were used to determine the effects on transcription of the HD gene and translation of wild-type and mutant protein. Results CircHTT expression increases significantly with increasing CAG repeats in terminally differentiated cortical neurons. Furthermore, circHtt is significantly more expressed in brain districts of Q111 and zQ175 knock-in mice. These findings indicate that the expression of circHTT/Htt occurs in a CAG repeat dependent manner in neuronal cells, typical hallmark of HD pathology. Strikingly, overexpression of the circular RNA in human HEK293T, PC3, mouse STHdh Q7/7, Q7/111 and Q111/111 cell lines consistently increase wild-type huntingtin, while decreasing mutant huntingtin protein, with no alteration of the HTT/Htt transcript level. Conclusions In conclusion, we identified a brain enriched RNA circle originating from the HD gene locus that is sensitive to the HD mutation and may modulate huntingtin expression. Our observations might pave the way to new trials of therapeutic intervention.","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116003379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A19 High-resolution respirometry as a tool to assess skeletal muscle mitochondrial state in patients with huntington’s disease","authors":"S. Kopishinskaia, P. Pchelin, M. Korotysh, T. Kovaleva, I. Mukhina, S. Svetozarsky","doi":"10.1136/jnnp-2021-ehdn.18","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.18","url":null,"abstract":"Background Along with the affected nervous system, muscle pathology stands out as a well-recognized hallmark of Huntington’s disease (HD) and manifested in muscle wasting, atrophy, and accompanied by defects in energy metabolism. High-resolution respirometry (HRR) can be considered a promising tool to determine alterations in mitochondrial function in premanifest and manifest HD patients. Aims To determine the feasibility of HRR in the assessment of skeletal muscle mitochondrial function in patients with HD. Methods Muscle samples were acquired by a fine-needle biopsy method from the middle part of the m. rectus femoris of 8 HD premanifest patients (age, mean ± SD, 27 ± 3.25 years), 8 manifest patients (43.1 ± 5.59 years), and 15 age and sex-matched controls (28.5 ± 3.21 years, matched to premanifest; 40.3 ± 5.59 years, matched to manifest). After mechanical preparation and permeabilization with saponin, changes in mtMP (mitochondrial membrane potential) were assessed simultaneously with respiration measurement using cell-permeant, cationic dye TMRM (tetramethylrhodamine, methyl ester), and HRR system Oroboros Oxygraph-2k (Oroboros Instruments, Austria). The data were normalized to the wet weight of samples; results (pmol O2/s/mg, means ± SD) were statistically analyzed using the Mann-Whitney test. Results The coupled respiration rates (both CI- and CI+CII-related respiration during oxidative phosphorylation) were lower in premanifest patients when compared to matched controls and manifests (CI: 20.7 ± 2.7 vs. 26.6 ± 2.0 and 27.9 ± 6.5, p Conclusions HRR can be used to assess mitochondrial state in skeletal muscles from patients with HD.","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121961808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A13 Abnormal spinal cord myelination due to oligodendrocyte dysfunction in a model of huntington disease","authors":"C. Bardile, H. Sidik, Reynard Quek, N. Yusof, M. Garcia-Miralles, M. Pouladi","doi":"10.1136/jnnp-2021-ehdn.12","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.12","url":null,"abstract":"Background The contribution of grey matter (GM) and white matter (WM) degeneration to the progressive brain atrophy in Huntington Disease (HD) has been well studied. The pathology of the spinal cord in HD is comparatively less well documented. Aim Here we sought to investigate spinal cord pathology in a mouse model of HD, and in particular WM and myelination abnormalities. Method To determine whether GM and WM regions are atrophied in the spinal cord of 12 months old BACHD mice, we measured the area of GM and WM in the spinal cord by histological assessment. Electron microscopy was used to analyze myelin fibers in the cervical area of the spinal cord, where g-ratio of myelinated axons was used as a measure of myelin thickness. To investigate the impact of inactivation of mutant huntingtin (mHTT) in oligodendroglia on these measures, we used the previously described BACHDxNG2Cre (BN) mouse line where mHTT is specifically reduced in oligodendrocyte progenitor cells (OPC). Results We show that spinal GM and WM areas are significantly atrophied in BACHD mice compared to wild-type (WT) controls. We further demonstrate that specific reduction of mHTT in oligodendroglial cells rescues the atrophy of spinal cord WM, but not GM, as observed in BACHD mice. Inactivation of mHTT in oligodendroglia had no effect on the density of oligodendroglial cells but enhanced the expression of myelin-related proteins in the spinal cord. Conclusions Overall, our findings firstly demonstrate that the myelination abnormalities observed in brain WM structures in HD extend to the spinal cord, and secondly, they suggest that specific expression of mHTT in oligodendrocytes contributes to such abnormalities.","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125780783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A07 Huntingtin-dependent stability of HAP40 and decreased HAP40 levels in huntington’s disease","authors":"Manuel Seefelder, Bin Huang, Eva Buck, T. Engler, K. Lindenberg, B. Landwehrmeyer, S. Kochanek","doi":"10.1136/jnnp-2021-ehdn.6","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.6","url":null,"abstract":"Background The huntingtin-associated protein 40 (HAP40) is an abundant interactor of huntingtin (HTT). In a complex of the two proteins, HAP40 tightly binds to HTT in a cleft formed by two larger domains, rich in HEAT repeats, and a smaller bridge domain that connects the two. When generating HEK293-based cell lines for producing the HTT-HAP40 complex for structural studies (Guo et al. 2020, Nature), enhancing HTT expression resulted in increased HAP40 steady-state levels. Aims/Methods By Western Blot analysis, we investigated whether HAP40 steady-state protein levels are directly dependent on HTT levels and whether HAP40 protein levels are decreased in samples (lymphocytes and fibroblasts) from Huntington’s disease (HD) patients and mouse models alongside HTT levels. Moreover, we assessed by cycloheximide-chase assay and qRT-PCR, respectively, if HAP40 protein stability or HAP40/F8A mRNA levels are dependent on HTT levels. Results We show that steady-state protein levels of HAP40 strongly correlated with and were directly dependent on HTT protein expression levels. While HAP40 alone had a very short half-life, HAP40 was stabilized upon HTT overexpression. Cellular HAP40 protein levels were reduced in primary fibroblasts and lymphoblasts of HD patients and in brain tissue of a well-characterized HD mouse model, concomitantly with decreased HTT levels in these cell types. Conclusion This data, together with our previous demonstration of likely coevolution of the two proteins and evolutionary conservation of their interaction in metazoans (Seefelder et al. 2020, BMC Evolutionary Biology) suggests that HAP40 is an obligate and likely functionally important interaction partner of HTT. Our observation of reduced HAP40 levels in HD indicates that loss-of-function phenotypes due to lowered HAP40 levels might contribute to the pathology in HD.","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132232004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A09 ADAM10 activity at the huntington’s disease presynapse","authors":"C. Zuccato, Flora Cozzolino, E. Vezzoli, C. Cheroni, D. Besusso, P. Conforti, M. Valenza, I. Iacobucci, Vittoria Monaco, Giulia Birolini, M. Bombaci, A. Falqui, P. Saftig, R. Rossi, M. Monti, E. Cattaneo","doi":"10.1136/jnnp-2021-ehdn.8","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.8","url":null,"abstract":"","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133453266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A18 Can cumulation of neurodegenerative disorders significantly promote mitochondrial dysfunction in cultured skin fibroblasts?","authors":"M. Vanišová, R. Matěj, R. Rusina, Hana Štufková, M. Kohoutová, T. Daňhelovská, J. Klempír, J. Roth, H. Hansíková","doi":"10.1136/jnnp-2021-ehdn.17","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.17","url":null,"abstract":"","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126211150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A03 Precise machine-learning suggests that neuronal death in HD is mainly driven by the loss of homeostatic responses","authors":"L. Mégret, B. Gris, Satish Sasidharan Nair, J. Cevost, M. Wertz, J. Aaronson, J. Rosinski, T. Vogt, H. Wilkinson, M. Heiman, C. Neri","doi":"10.1136/jnnp-2021-ehdn.3","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.3","url":null,"abstract":"","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133499476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A15 Hypothalamic expression of huntingtin causes distinct metabolic changes in the R6/2 and bachd mouse models of huntington’s disease","authors":"Elna Dickson, Rana Soylu Kucharz, Å. Petersén, M. Björkqvist","doi":"10.1136/jnnp-2021-ehdn.14","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.14","url":null,"abstract":"","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131289527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A08 Synaptic vesicle recycling is disrupted in a mouse model of huntington’s disease","authors":"Robyn McAdam, M. Cousin, K. J. Smillie","doi":"10.1136/jnnp-2021-ehdn.7","DOIUrl":"https://doi.org/10.1136/jnnp-2021-ehdn.7","url":null,"abstract":"Background An emerging theme in neurodegenerative diseases, including Huntington’s Disease (HD), is that presynaptic dysfunction plays a role in neurodegeneration and disease progression. In HD the huntingtin protein (Htt) produced has an expanded polyglutamine stretch, likely causing altered protein function. Htt is enriched at the presynapse, suggesting it may have a role in presynaptic function. At the presynapse, synaptic vesicles fuse with the plasma membrane in a process called exocytosis to release neurotransmitter into the synaptic cleft. Following exocytosis, synaptic vesicles are retrieved and recycled via endocytosis. If this cycle is disrupted, synaptic frailty and degeneration can occur. Aims The aim of this study was to investigate presynaptic function in a mouse model of HD. Methods Primary neuronal cultures were made from Q140 knock-in mice and wild-type (wt) controls. Presynaptic function was monitored using the genetically encoded reporter, synaptophysin-phluorin, in combination with manipulation of the levels of Htt. This was achieved by silencing expression using hsiRNA or over-expression of Htt. Results We demonstrate that striatal primary neurons from Q140 mice display an activity-dependent slowing of endocytosis. Silencing of mutant Htt in Q140 cultures had no effect on endocytic rate, however, silencing of wt-Htt in control cultures, recapitulated the defect. This suggests a loss of Htt function phenotype. Supporting this, over-expression of wt-Htt in Q140 neurons rescued the endocytic defect. Slowing of endocytosis was also observed in heterozygous cultures, which more accurately represents the genetics of HD patients. Conclusions We have uncovered a loss of wt-Htt, activity-dependent presynaptic defect in a model of HD. This is important because understanding the mechanisms underpinning events which occur early in disease progression may represent new targets for therapeutic intervention.","PeriodicalId":403341,"journal":{"name":"A: Pathogenic mechanisms","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130583882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}