Formation and spreading of TDP-43 aggregates in cultured neuronal and glial cells demonstrated by time-lapse imaging

• Published in: PloS one 2017-06, Vol.12 (6), p.e0179375-e0179375
• Main Authors: Ishii, Tomohiro, Kawakami, Emiko, Endo, Kentaro, Misawa, Hidemi, Watabe, Kazuhiko
• Format: Article
• Language: English
• Subjects: Adenoviruses; Aggregates; Amyotrophic lateral sclerosis; Animals; Astrocytes; Biology and Life Sciences; Biotechnology; Care and treatment; Cell culture; Cell Death; Cell lines; Cell spreading; Cells, Cultured; Collapse; Culture media; Cytoplasm; Degeneration; Deoxyribonucleic acid; DNA; DNA-binding protein; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Expression vectors; Fragmentation; Frontotemporal dementia; Glial cells; Glial fibrillary acidic protein; Granular materials; Humans; Imaging; In vitro methods and tests; Inhibition; Kinases; Medicine and Health Sciences; Molecular modelling; Mortality; Neural stem cells; Neural Stem Cells - metabolism; Neural Stem Cells - pathology; Neural Stem Cells - ultrastructure; Neurodegeneration; Neuroglia - metabolism; Neuroglia - pathology; Neuroglia - ultrastructure; Neuroimaging; Neuronal-glial interactions; Neurons; Neurons - metabolism; Neurons - pathology; Neurons - ultrastructure; Oligodendrocytes; Pathology; Phosphodiesterase; Phosphorylation; Proteasome Endopeptidase Complex - metabolism; Proteasomes; Protein Aggregates; Protein Aggregation, Pathological; Protein binding; Protein Transport; Proteins; Rats; Research and Analysis Methods; Retinoic acid; RNA, Small Interfering - genetics; Time-Lapse Imaging; Tubulin
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0179375

TAR DNA-binding protein 43 (TDP-43) is a main constituent of cytoplasmic aggregates in neuronal and glial cells in cases of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. We have previously demonstrated that adenovirus-transduced artificial TDP-43 cytoplasmic aggregates formation is enhanced by proteasome inhibition in vitro and in vivo. However, the relationship between cytoplasmic aggregate formation and cell death remains unclear. In the present study, rat neural stem cell lines stably transfected with EGFP- or Sirius-expression vectors under the control of tubulin beta III, glial fibrillary acidic protein, or 2',3'-cyclic nucleotide 3'-phosphodiesterase promoter were differentiated into neurons, astrocytes, and oligodendrocytes, respectively, in the presence of retinoic acid. The differentiated cells were then transduced with adenoviruses expressing DsRed-tagged human wild type and C-terminal fragment TDP-43 under the condition of proteasome inhibition. Time-lapse imaging analyses revealed growing cytoplasmic aggregates in the transduced neuronal and glial cells, followed by collapse of the cell. The aggregates remained insoluble in culture media, consisted of sarkosyl-insoluble granular materials, and contained phosphorylated TDP-43. Moreover, the released aggregates were incorporated into neighboring neuronal cells, suggesting cell-to-cell spreading. The present study provides a novel tool for analyzing the detailed molecular mechanisms of TDP-43 proteinopathy in vitro.