DNA damage, redox changes, and associated stress-inducible signaling events underlying the apoptosis and cytotoxicity in murine alveolar macrophage cell line MH-S by methanol-extracted Stachybotrys chartarum toxins

Journal Article · Tue Aug 01 04:00:00 EDT 2006 · Toxicology and Applied Pharmacology

DOI:https://doi.org/10.1016/j.taap.2006.01.002· OSTI ID:20850383

Huiyan, Wang ^[1]; Yadav, Jagjit S ^[1]

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1. Division of Environmental Genetics and Molecular Toxicology, Department of Environmental Health, University of Cincinnati Medical Center, Cincinnati, OH 45267 (United States)

Spore-extracted toxins of the indoor mold Stachybotrys chartarum (SC) caused cytotoxicity (release of lactate dehydrogenase), inhibition of cell proliferation, and cell death in murine alveolar macrophage cell line MH-S in a dose- and time-dependent manner. Apoptotic cell death, confirmed based on morphological changes, DNA ladder formation, and caspase 3/7 activation, was detectable as early as at 3 h during treatment with a toxin concentration of 1 spore equivalent/macrophage and was preceded by DNA damage beginning at 15 min, as evidenced by DNA comet formation in single cell gel electrophoresis assay. The apoptotic dose of SC toxins did not induce detectable nitric oxide and pro-inflammatory cytokines (IL-1{beta}, IL-6, and TNF-{alpha}) but showed exacerbated cytotoxicity in presence of a non-apoptotic dose of the known pro-inflammatory agent LPS (10 ng/ml). Intracellular reduced glutathione (GSH) level showed a significant decrease beginning at 9 h of the toxin treatment whereas oxidized glutathione (GSSG) showed a corresponding significant increase, indicating a delayed onset of oxidative stress in the apoptosis process. The toxin-treated macrophages accumulated p53, an indicator of DNA damage response, and showed activation of the stress-inducible MAP kinases, JNK, and p38, in a time-dependent manner. Chemical blocking of either p38 or p53 inhibited in part the SC toxin-induced apoptosis whereas blocking of JNK did not show any such effect. This study constitutes the first report on induction of DNA damage and associated p53 activation by SC toxins, and demonstrates the involvement of p38- and p53-mediated signaling events in SC toxin-induced apoptosis of alveolar macrophages.

• OSTI ID: 20850383
• Journal Information: Toxicology and Applied Pharmacology, Journal Name: Toxicology and Applied Pharmacology Journal Issue: 3 Vol. 214; ISSN TXAPA9; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
APOPTOSIS
BIOLOGICAL STRESS
CELL PROLIFERATION
DNA DAMAGES
ELECTROPHORESIS
FUNGI
GLUTATHIONE
INFLAMMATION
INHIBITION
LACTATE DEHYDROGENASE
LYMPHOKINES
MACROPHAGES
METHANOL
MORPHOLOGICAL CHANGES
NITRIC OXIDE
PHOSPHORUS 38
PHOSPHOTRANSFERASES
RADIATION DOSES
SPORES
TIME DEPENDENCE
TOXICITY
TOXINS