XBP1 depletion precedes ubiquitin aggregation and Golgi fragmentation in TDP-43 transgenic rats Article

Tong, J, Huang, C, Bi, F et al. (2012). XBP1 depletion precedes ubiquitin aggregation and Golgi fragmentation in TDP-43 transgenic rats . JOURNAL OF NEUROCHEMISTRY, 123(3), 406-416. 10.1111/jnc.12014

cited authors

  • Tong, J; Huang, C; Bi, F; Wu, Q; Huang, B; Zhou, H

authors

abstract

  • Protein inclusion is a prominent feature of neurodegenerative diseases including frontotemporal lobar degeneration (FTLD) that is characterized by the presence of ubiquitinated TDP-43 inclusion. Presence of protein inclusions indicates an interruption to protein degradation machinery or the overload of misfolded proteins. In response to the increase in misfolded proteins, cells usually initiate a mechanism called unfolded protein response (UPR) to reduce misfolded proteins in the lumen of endoplasmic reticules. Here, we examined the effects of mutant TDP-43 on the UPR in transgenic rats that express mutant human TDP-43 restrictedly in the neurons of the forebrain. Over-expression of mutant TDP-43 in rats caused prominent aggregation of ubiquitin and remarkable fragmentation of Golgi complexes prior to neuronal loss. While ubiquitin aggregates and Golgi fragments were accumulating, neurons expressing mutant TDP-43 failed to up-regulate chaperones residing in the endoplasmic reticules and failed to initiate the UPR. Prior to ubiquitin aggregation and Golgi fragmentation, neurons were depleted of X-box-binding protein 1 (XBP1), a key player of UPR machinery. Although it remains to determine how mutation of TDP-43 leads to the failure of the UPR, our data demonstrate that failure of the UPR is implicated in TDP-43 pathogenesis. Electromicroscopy reveals that ER is severely vacuolated in neurons while mitochondrial morphology is largely intact. ER likely is the preferable targets of degeneration caused by mutation in TDP-43. © 2012 International Society for Neurochemistry.

publication date

  • November 1, 2012

published in

Digital Object Identifier (DOI)

start page

  • 406

end page

  • 416

volume

  • 123

issue

  • 3