Endoplasmic reticulum stress mediates nitric oxide-induced chondrocyte apoptosis

  • Authors:
    • Koji Takada
    • Jun Hirose
    • Soichiro Yamabe
    • Yushuke Uehara
    • Hiroshi Mizuta
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  • Published online on: January 3, 2013     https://doi.org/10.3892/br.2013.52
  • Pages: 315-319
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Abstract

Nitric oxide (NO) is one of the most important mediators of chondrocyte apoptosis, which is a notable feature of cartilage degeneration. While apoptosis of chondrocytes is induced by p53, NO can also induce endoplasmic reticulum (ER) stress, which may be involved in the process of NO-induced chondrocyte apoptosis. The aims of this study were to determine whether NO-induced ER stress (ERS) leads to apoptosis of chondrocytes and to investigate the temporal relationship between the expression of C/EBP-homologous protein (CHOP), an ERS-associated apoptotic molecule, and the expression of p53 during apoptosis in NO‑stimulated chondrocytes. Rat chondrocytes were stimulated by sodium nitroprusside (SNP), a NO donor. Real-time polymerase chain reaction (PCR) was performed to analyze the mRNA expression of CHOP, glucose-regulated protein (GRP78) and p53. Apoptosis of chondrocytes was quantified using an enzyme-linked immunosorbent assay (ELISA). SNP‑treated chondrocytes showed an increase in CHOP and GRP78 mRNA expression and underwent apoptosis. Sodium 4-phenylbutyrate (PBA), an ERS inhibitor, reduced CHOP and GRP78, as well as SNP‑stimulated apoptosis of chondrocytes, without affecting the SNP-dependent generation of NO. In addition, the blockade of CHOP following siRNA transfection reduced SNP‑induced apoptosis of chondrocytes. The CHOP expression increased after apoptosis was detected in the SNP-treated chondrocytes, whereas the p53 expression increased prior to apoptosis. These data demonstrated that NO-induced ERS leads chondrocytes to apoptosis, although this effect appears to be limited to persistent impairment of NO stimulation. These findings may provide insight into the pathology of cartilage degeneration.
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March-April 2013
Volume 1 Issue 2

Print ISSN: 2049-9434
Online ISSN:2049-9442

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APA
Takada, K., Hirose, J., Yamabe, S., Uehara, Y., & Mizuta, H. (2013). Endoplasmic reticulum stress mediates nitric oxide-induced chondrocyte apoptosis. Biomedical Reports, 1, 315-319. https://doi.org/10.3892/br.2013.52
MLA
Takada, K., Hirose, J., Yamabe, S., Uehara, Y., Mizuta, H."Endoplasmic reticulum stress mediates nitric oxide-induced chondrocyte apoptosis". Biomedical Reports 1.2 (2013): 315-319.
Chicago
Takada, K., Hirose, J., Yamabe, S., Uehara, Y., Mizuta, H."Endoplasmic reticulum stress mediates nitric oxide-induced chondrocyte apoptosis". Biomedical Reports 1, no. 2 (2013): 315-319. https://doi.org/10.3892/br.2013.52