Induction of CHOP and apoptosis by nitric oxide in p53-deficient microglial cells

• Published in: FEBS letters 2001-10, Vol.506 (2), p.135-139
• Main Authors: Kawahara, Kohichi, Oyadomari, Seiichi, Gotoh, Tomomi, Kohsaka, Shinichi, Nakayama, Hitoshi, Mori, Masataka
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Carrier Proteins - genetics; Carrier Proteins - metabolism; CCAAT-Enhancer-Binding Proteins - genetics; CCAAT-Enhancer-Binding Proteins - metabolism; Cell Line; CHOP; Endoplasmic reticulum stress; ER, endoplasmic reticulum; Gene Expression Regulation; Heat-Shock Proteins; IFN-γ, interferon-γ; iNOS, inducible NO synthase; Interferon-gamma - pharmacology; Lipopolysaccharide; Lipopolysaccharides - pharmacology; LPS, lipopolysaccharide; Mice; Microglia; Microglia - cytology; Microglia - drug effects; Microglia - metabolism; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Nitric oxide; Nitric Oxide - metabolism; Nitric Oxide Synthase - genetics; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase Type II; NO, nitric oxide; p53; S-Nitroso-N-Acetylpenicillamine - pharmacology; SIN-1, 3-(4-morpholinyl)-sydnonimine hydrochloride; SNAP, S-nitroso-N-acetyl-DL-penicillamine; Transcription Factor CHOP; Transcription Factors - genetics; Transcription Factors - metabolism; Tumor Suppressor Protein p53 - deficiency; Tumor Suppressor Protein p53 - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(01)02898-8

Excessive nitric oxide (NO) has been implicated in neurotoxicity after stresses such as ischemia. NO toxicity is generally thought to be mediated by the DNA damage–p53 pathway or mitochondrial dysfunction. We investigated the mechanism of NO toxicity by using murine microglial MG5 cells established from p53-deficient mice. When MG5 cells were exposed to bacterial lipopolysaccharide plus interferon-γ, mRNA and protein for inducible NO synthase (iNOS) were markedly induced, and apoptosis occurred. Under these conditions, we found that mRNA and protein for CHOP/GADD153, a C/EBP family transcription factor which is involved in endoplasmic reticulum (ER) stress-induced apoptosis, are induced. iNOS mRNA was induced 2 h after treatment, whereas CHOP mRNA began to increase at 6 h with a time lag. CHOP mRNA was also induced by NO donors S-nitroso- N-acetyl- DL-penicillamine (SNAP) or NOC18, or a peroxynitrite generator 3-(4-morpholinyl)-sydnonimine hydrochloride (SIN-1). Bip/GRP78, an ER chaperone which is known to be induced by ER stress, was also induced by SNAP or SIN-1, indicating that NO causes ER stress. These results suggest that NO-induced apoptosis in MG5 cells occurs through the ER stress pathway involving CHOP, but is independent of p53.