KHSRP participates in manganese-induced neurotoxicity in rat striatum and PC12 cells

J Mol Neurosci. 2015 Feb;55(2):454-65. doi: 10.1007/s12031-014-0367-7. Epub 2014 Jul 16.

Abstract

Manganese (Mn) is an essential micronutrient. However, exposure to high doses of Mn may lead to a neurological disease known as manganism, which is characterized by marked brain neuronal loss. K-homology splicing regulator protein (KHSRP) is a multifunctional RNA-binding protein and has been implicated in the regulation of multiple cellular signaling associated with neuronal apoptosis and survival, such as p38 mitogen-activated protein kinase (MAPK), nuclear factor kappaB (NF-κB), and Wnt/β-catenin pathways. In the present study, the role of KHSRP in Mn-induced neurotoxicity was investigated in vivo using a rat model of chronic Mn exposure and in vitro using differentiated PC12 cell cultures. Western blot and immunohistochemical analyses showed a significant upregulation of KHSRP in rat striatum following Mn exposure. Immunofluorescent labeling indicated that KHSRP was localized mainly in neurons. Terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick end labeling (TUNEL) assay showed that KHSRP was mainly distributed in apoptotic neurons. Increased KHSRP expression was positively correlated with the upregulation of several apoptosis-related proteins, such as p53, bax, and active caspase-3. In addition, significant co-localization of KHSRP and active caspase-3 in neurons after Mn exposure was also observed, suggesting a potential involvement of KHSRP in the regulation of Mn-induced striatal neuronal apoptosis. Importantly, interference with KHSRP apparently decreased the level of p53 and attenuated Mn-induced neuronal apoptosis. Taken together, these results indicate that upregulation of KHSRP may be involved in the pathological process underlying Mn neurotoxicity via the modulation of p53 signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Corpus Striatum / drug effects
  • Corpus Striatum / metabolism*
  • Male
  • Manganese / toxicity*
  • Neurons / drug effects
  • Neurons / metabolism
  • PC12 Cells
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • KHSRP protein, rat
  • RNA-Binding Proteins
  • Trans-Activators
  • Tumor Suppressor Protein p53
  • Manganese