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Title: Mechanisms for ribotoxin-induced ribosomal RNA cleavage

Abstract

The Type B trichothecene deoxynivalenol (DON), a ribotoxic mycotoxin known to contaminate cereal-based foods, induces ribosomal RNA (rRNA) cleavage in the macrophage via p38-directed activation of caspases. Here we employed the RAW 264.7 murine macrophage model to test the hypothesis that this rRNA cleavage pathway is similarly induced by other ribotoxins. Capillary electrophoresis confirmed that the antibiotic anisomycin (≥ 25 ng/ml), the macrocylic trichothecene satratoxin G (SG) (≥ 10 ng/ml) and ribosome-inactivating protein ricin (≥ 300 ng/ml) induced 18s and 28s rRNA fragmentation patterns identical to that observed for DON. Also, as found for DON, inhibition of p38, double-stranded RNA-activated kinase (PKR) and hematopoietic cell kinase (Hck) suppressed MAPK anisomycin-induced rRNA cleavage, while, in contrast, their inhibition did not affect SG- and ricin-induced rRNA fragmentation. The p53 inhibitor pifithrin-μ and pan caspase inhibitor Z-VAD-FMK suppressed rRNA cleavage induced by anisomycin, SG and ricin, indicating that these ribotoxins shared with DON a conserved downstream pathway. Activation of caspases 8, 9 and 3 concurrently with apoptosis further suggested that rRNA cleavage occurred in parallel with both extrinsic and intrinsic pathways of programmed cell death. When specific inhibitors of cathepsins L and B (lysosomal cysteine cathepsins active at cytosolic neutral pH) were tested,more » only the former impaired anisomycin-, SG-, ricin- and DON-induced rRNA cleavage. Taken together, the data suggest that (1) all four ribotoxins induced p53-dependent rRNA cleavage via activation of cathepsin L and caspase 3, and (2) activation of p53 by DON and anisomycin involved p38 whereas SG and ricin activated p53 by an alternative mechanism. Highlights: ► Deoxynivalenol (DON) anisomycin, satratoxin G (SG) and ricin are ribotoxins. ► Ribotoxins induce 18s and 28s rRNA cleavage in the RAW 264.7 macrophage model. ► Ribotoxins induce rRNA cleavage via activation of p53, caspases and cathepsins. ► DON- and anisomycin-triggered rRNA cleavage is p38-dependent. ► SG- and ricin-induced rRNA cleavage is p38-independent.« less

Authors:
 [1];  [2];  [3];  [1];  [2];  [2]
  1. Department of Microbiology and Molecular Genetics (United States)
  2. (United States)
  3. Food Science and Human Nutrition (United States)
Publication Date:
OSTI Identifier:
22215970
Resource Type:
Journal Article
Journal Name:
Toxicology and Applied Pharmacology
Additional Journal Information:
Journal Volume: 265; Journal Issue: 1; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0041-008X
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ANTIBIOTICS; APOPTOSIS; CAPILLARIES; CATHEPSINS; CEREALS; CYSTEINE; ELECTROPHORESIS; FOOD; INHIBITION; MACROPHAGES; PH VALUE; RIBOSOMAL RNA

Citation Formats

He, Kaiyu, Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, Zhou, Hui-Ren, Pestka, James J., E-mail: pestka@msu.edu, Food Science and Human Nutrition, and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824. Mechanisms for ribotoxin-induced ribosomal RNA cleavage. United States: N. p., 2012. Web. doi:10.1016/J.TAAP.2012.09.017.
He, Kaiyu, Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, Zhou, Hui-Ren, Pestka, James J., E-mail: pestka@msu.edu, Food Science and Human Nutrition, & Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824. Mechanisms for ribotoxin-induced ribosomal RNA cleavage. United States. doi:10.1016/J.TAAP.2012.09.017.
He, Kaiyu, Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, Zhou, Hui-Ren, Pestka, James J., E-mail: pestka@msu.edu, Food Science and Human Nutrition, and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824. Thu . "Mechanisms for ribotoxin-induced ribosomal RNA cleavage". United States. doi:10.1016/J.TAAP.2012.09.017.
@article{osti_22215970,
title = {Mechanisms for ribotoxin-induced ribosomal RNA cleavage},
author = {He, Kaiyu and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824 and Zhou, Hui-Ren and Pestka, James J., E-mail: pestka@msu.edu and Food Science and Human Nutrition and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824},
abstractNote = {The Type B trichothecene deoxynivalenol (DON), a ribotoxic mycotoxin known to contaminate cereal-based foods, induces ribosomal RNA (rRNA) cleavage in the macrophage via p38-directed activation of caspases. Here we employed the RAW 264.7 murine macrophage model to test the hypothesis that this rRNA cleavage pathway is similarly induced by other ribotoxins. Capillary electrophoresis confirmed that the antibiotic anisomycin (≥ 25 ng/ml), the macrocylic trichothecene satratoxin G (SG) (≥ 10 ng/ml) and ribosome-inactivating protein ricin (≥ 300 ng/ml) induced 18s and 28s rRNA fragmentation patterns identical to that observed for DON. Also, as found for DON, inhibition of p38, double-stranded RNA-activated kinase (PKR) and hematopoietic cell kinase (Hck) suppressed MAPK anisomycin-induced rRNA cleavage, while, in contrast, their inhibition did not affect SG- and ricin-induced rRNA fragmentation. The p53 inhibitor pifithrin-μ and pan caspase inhibitor Z-VAD-FMK suppressed rRNA cleavage induced by anisomycin, SG and ricin, indicating that these ribotoxins shared with DON a conserved downstream pathway. Activation of caspases 8, 9 and 3 concurrently with apoptosis further suggested that rRNA cleavage occurred in parallel with both extrinsic and intrinsic pathways of programmed cell death. When specific inhibitors of cathepsins L and B (lysosomal cysteine cathepsins active at cytosolic neutral pH) were tested, only the former impaired anisomycin-, SG-, ricin- and DON-induced rRNA cleavage. Taken together, the data suggest that (1) all four ribotoxins induced p53-dependent rRNA cleavage via activation of cathepsin L and caspase 3, and (2) activation of p53 by DON and anisomycin involved p38 whereas SG and ricin activated p53 by an alternative mechanism. Highlights: ► Deoxynivalenol (DON) anisomycin, satratoxin G (SG) and ricin are ribotoxins. ► Ribotoxins induce 18s and 28s rRNA cleavage in the RAW 264.7 macrophage model. ► Ribotoxins induce rRNA cleavage via activation of p53, caspases and cathepsins. ► DON- and anisomycin-triggered rRNA cleavage is p38-dependent. ► SG- and ricin-induced rRNA cleavage is p38-independent.},
doi = {10.1016/J.TAAP.2012.09.017},
journal = {Toxicology and Applied Pharmacology},
issn = {0041-008X},
number = 1,
volume = 265,
place = {United States},
year = {2012},
month = {11}
}