title: Cytoplasmic accumulation and aggregation of TDP-43 upon proteasome inhibition in cultured neurons.
abstract: Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are characterized by intraneuronal deposition of the nuclear TAR DNA-binding protein 43 (TDP-43) caused by unknown mechanisms. Here, we studied TDP-43 in primary neurons under different stress conditions and found that only proteasome inhibition by MG-132 or lactacystin could induce significant cytoplasmic accumulation of TDP-43, a histopathological hallmark in disease. This cytoplasmic accumulation was accompanied by phosphorylation, ubiquitination and aggregation of TDP-43, recapitulating major features of disease. Proteasome inhibition produced similar effects in both hippocampal and cortical neurons, as well as in immortalized motor neurons. To determine the contribution of TDP-43 to cell death, we reduced TDP-43 expression using small interfering RNA (siRNA), and found that reduced levels of TDP-43 dose-dependently rendered neurons more vulnerable to MG-132. Taken together, our data suggests a role for the proteasome in subcellular localization of TDP-43, and possibly in disease.
authors.affiliation: Laboratory for Translational Neurodegeneration, Brain & Mind Research Institute, University of Sydney, Sydney, Australia.
authors.forename: Janet
authors.initials: J
authors.lastname: van Eersel
authors.forename: Yazi D
authors.initials: YD
authors.lastname: Ke
authors.forename: Amadeus
authors.initials: A
authors.lastname: Gladbach
authors.forename: Mian
authors.initials: M
authors.lastname: Bi
authors.forename: Jürgen
authors.initials: J
authors.lastname: Götz
authors.forename: Jillian J
authors.initials: JJ
authors.lastname: Kril
authors.forename: Lars M
authors.initials: LM
authors.lastname: Ittner
mesh_terms: D000818:Animals; D015153:Blotting, Western; D016923:Cell Death / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D007976:Leupeptins / Q000494:pharmacology; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D010766:Phosphorylation; D061988:Proteasome Inhibitors; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D013347:Subcellular Fractions; D054875:Ubiquitination
chemical_list: D015853:Cysteine Proteinase Inhibitors; D004268:DNA-Binding Proteins; D007976:Leupeptins; D061988:Proteasome Inhibitors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde