RGD Reference Report - Enhanced expression of C/EBP homologous protein (CHOP) precedes degeneration of fibrocytes in the lateral wall after acute cochlear mitochondrial dysfunction induced by 3-nitropropionic acid. - Rat Genome Database

Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

Enhanced expression of C/EBP homologous protein (CHOP) precedes degeneration of fibrocytes in the lateral wall after acute cochlear mitochondrial dysfunction induced by 3-nitropropionic acid.

Authors: Fujinami, Yoshiaki  Mutai, Hideki  Kamiya, Kazusaku  Mizutari, Kunio  Fujii, Masato  Matsunaga, Tatsuo 
Citation: Fujinami Y, etal., Neurochem Int. 2010 Feb;56(3):487-94. doi: 10.1016/j.neuint.2009.12.008. Epub 2009 Dec 21.
RGD ID: 13464338
Pubmed: PMID:20026213   (View Abstract at PubMed)
DOI: DOI:10.1016/j.neuint.2009.12.008   (Journal Full-text)

We previously reported that treatment of the rat cochlea with a mitochondrial toxin, 3-nitropropionic acid (3-NP), causes temporary to permanent hearing loss depending on the amount of the drug. Furthermore, apoptosis of cochlear lateral wall fibrocytes, which are important for maintaining the endolymph, is a predominant pathological feature in this animal model. 3-NP is known to induce oxidative stress as well as neuronal apoptosis. C/EBP homologous protein gene (chop) is one of the marker genes induced during endoplasmic reticulum (ER) stress, and is also considered to be involved in apoptosis. To elucidate the molecular mechanism of cochlear fibrocyte apoptosis induced by 3-NP, we studied spatiotemporal expression of C/EBP homologous protein (CHOP) and other signaling molecules related to ER stress as well as the appearance of apoptotic cells in the cochlear lateral wall after 3-NP treatment. Quantitative real-time PCR revealed that chop and activating transcription factor 4 gene (atf-4) showed marked increase within 6h, whereas expression of other ER stress-responsive genes such as grp78 and grp94 did not change. Immunohistochemistry showed that 3-NP treatment caused up-regulation of CHOP, especially in type II and type IV fibrocytes, followed by the appearance of terminal deoxynucleotidyl transferase mediated dUTP nick end-labeling (TUNEL)-positive apoptotic cells in the same confined area. Thus, apoptosis of lateral wall fibrocytes induced by 3-NP is likely to be mediated by induction of CHOP. These results contribute clarification of pathological mechanism of cochlear fibrocytes and may lead to development of novel therapeutic strategy for hearing loss.




Biological Process

  
Object Symbol
Species
Term
Qualifier
Evidence
With
Notes
Source
Original Reference(s)
Atf4Ratresponse to toxic substance  IEP 3-nitropropionic acid CHEBI:16348RGD 
Ddit3Ratresponse to toxic substance  IEP 3-nitropropionic acid CHEBI:16348RGD 


Genes (Rattus norvegicus)
Atf4  (activating transcription factor 4) Ddit3  (DNA-damage inducible transcript 3)