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Chang HH, Wang TP, Chen PK, Lin YY, Liao CH, Lin TK, Chiang YW, Lin WB, Chiang CY, Kau JH, Huang HH, Hsu HL, Liao CY, Sun DS. Erythropoiesis suppression is associated with anthrax lethal toxin-mediated pathogenic progression. PLoS One 2013; 8:e71718. [PMID: 23977125 PMCID: PMC3747219 DOI: 10.1371/journal.pone.0071718] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 07/01/2013] [Indexed: 01/01/2023] Open
Abstract
Anthrax is a disease caused by the bacterium Bacillus anthracis, which results in high mortality in animals and humans. Although some of the mechanisms are already known such as asphyxia, extensive knowledge of molecular pathogenesis of this disease is deficient and remains to be further investigated. Lethal toxin (LT) is a major virulence factor of B. anthracis and a specific inhibitor/protease of mitogen-activated protein kinase kinases (MAPKKs). Anthrax LT causes lethality and induces certain anthrax-like symptoms, such as anemia and hypoxia, in experimental mice. Mitogen-activated protein kinases (MAPKs) are the downstream pathways of MAPKKs, and are important for erythropoiesis. This prompted us to hypothesize that anemia and hypoxia may in part be exacerbated by erythropoietic dysfunction. As revealed by colony-forming cell assays in this study, LT challenges significantly reduced mouse erythroid progenitor cells. In addition, in a proteolytic activity-dependent manner, LT suppressed cell survival and differentiation of cord blood CD34+-derived erythroblasts in vitro. Suppression of cell numbers and the percentage of erythroblasts in the bone marrow were detected in LT-challenged C57BL/6J mice. In contrast, erythropoiesis was provoked through treatments of erythropoietin, significantly ameliorating the anemia and reducing the mortality of LT-treated mice. These data suggested that suppressed erythropoiesis is part of the pathophysiology of LT-mediated intoxication. Because specific treatments to overcome LT-mediated pathogenesis are still lacking, these efforts may help the development of effective treatments against anthrax.
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Affiliation(s)
- Hsin-Hou Chang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
| | - Tsung-Pao Wang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Po-Kong Chen
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
| | - Yo-Yin Lin
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
| | - Chih-Hsien Liao
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Ting-Kai Lin
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Ya-Wen Chiang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Wen-Bin Lin
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Chih-Yu Chiang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Jyh-Hwa Kau
- Department of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan
| | - Hsin-Hsien Huang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Hui-Ling Hsu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Chi-Yuan Liao
- Department of Obstetrics and Gynecology, Mennonite Christian HospitalHualien, Taiwan
| | - Der-Shan Sun
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
- * E-mail:
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Chen PK, Chang HH, Lin GL, Wang TP, Lai YL, Lin TK, Hsieh MC, Kau JH, Huang HH, Hsu HL, Liao CY, Sun DS. Suppressive effects of anthrax lethal toxin on megakaryopoiesis. PLoS One 2013; 8:e59512. [PMID: 23555687 PMCID: PMC3605335 DOI: 10.1371/journal.pone.0059512] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 02/15/2013] [Indexed: 01/14/2023] Open
Abstract
Anthrax lethal toxin (LT) is a major virulence factor of Bacillus anthracis. LT challenge suppresses platelet counts and platelet function in mice, however, the mechanism responsible for thrombocytopenia remains unclear. LT inhibits cellular mitogen-activated protein kinases (MAPKs), which are vital pathways responsible for cell survival, differentiation, and maturation. One of the MAPKs, the MEK1/2-extracellular signal-regulated kinase pathway, is particularly important in megakaryopoiesis. This study evaluates the hypothesis that LT may suppress the progenitor cells of platelets, thereby inducing thrombocytopenic responses. Using cord blood-derived CD34(+) cells and mouse bone marrow mononuclear cells to perform in vitro differentiation, this work shows that LT suppresses megakaryopoiesis by reducing the survival of megakaryocytes. Thrombopoietin treatments can reduce thrombocytopenia, megakaryocytic suppression, and the quick onset of lethality in LT-challenged mice. These results suggest that megakaryocytic suppression is one of the mechanisms by which LT induces thrombocytopenia. These findings may provide new insights for developing feasible approaches against anthrax.
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Affiliation(s)
- Po-Kong Chen
- Institute of Medical Science, Tzu-Chi University, Hualien, Taiwan
| | - Hsin-Hou Chang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
- Institute of Medical Science, Tzu-Chi University, Hualien, Taiwan
| | - Guan-Ling Lin
- Institute of Medical Science, Tzu-Chi University, Hualien, Taiwan
| | - Tsung-Pao Wang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Yi-Ling Lai
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Ting-Kai Lin
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Ming-Chun Hsieh
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Jyh-Hwa Kau
- Department of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan
| | - Hsin-Hsien Huang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Hui-Ling Hsu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Chi-Yuan Liao
- Department of Obstetrics and Gynecology, Mennonite Christian Hospital, Hualien, Taiwan
| | - Der-Shan Sun
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
- Institute of Medical Science, Tzu-Chi University, Hualien, Taiwan
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