Vibrio vulnificus MO6-24/O Lipopolysaccharide Stimulates Superoxide Anion, Thromboxane B2, Matrix Metalloproteinase-9, Cytokine and Chemokine Release by Rat Brain Microglia in Vitro

Marine Drugs

Alejandro M. S. Mayer³  Mary L. Hall³  Michael Holland³  Cristina De Castro¹  Antonio Molinaro¹  Monica Aldulescu³  Jeffrey Frenkel³  Lauren Ottenhoff³  David Rowley² 

[1]Department of Chemical Sciences, University of Napoli, Via Cintia 4, 80126 Napoli, Italy

[2] E-Mails:

[3]Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA

[4] E-Mail:

[5]Department of Pharmacology, Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, IL 60515, USA

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关键词: LPS;    Escherichia coli;    Vibrio vulnificus;    rat microglia;    cytokine;    chemokine;    superoxide;    thromboxane;    metalloproteinase;    neuroinflammation;    MMP-9;   

DOI  :  10.3390/md12041732

来源: mdpi

【 摘 要 】

Although human exposure to Gram-negative Vibrio vulnificus (V. vulnificus) lipopolysaccharide (LPS) has been reported to result in septic shock, its impact on the central nervous system’s innate immunity remains undetermined. The purpose of this study was to determine whether V. vulnificus MO6-24/O LPS might activate rat microglia in vitro and stimulate the release of superoxide anion (O₂⁻), a reactive oxygen species known to cause oxidative stress and neuronal injury in vivo. Brain microglia were isolated from neonatal rats, and then treated with either V. vulnificus MO6-24/O LPS or Escherichia coli O26:B6 LPS for 17 hours in vitro. O₂⁻ was determined by cytochrome C reduction, and matrix metalloproteinase-2 (MMP-2) and MMP-9 by gelatinase zymography. Generation of cytokines tumor necrosis factor alpha (TNF-α), interleukin-1 alpha (IL-1α), IL-6, and transforming growth factor-beta 1 (TGF-β1), chemokines macrophage inflammatory protein (MIP-1α)/chemokine (C-C motif) ligand 3 (CCL3), MIP-2/chemokine (C-X-C motif) ligand 2 (CXCL2), monocyte chemotactic protein-1 (MCP-1)/CCL2, and cytokine-induced neutrophil chemoattractant-2alpha/beta (CINC-2α/β)/CXCL3, and brain-derived neurotrophic factor (BDNF), were determined by specific immunoassays. Priming of rat microglia by V. vulnificus MO6-24/O LPS in vitro yielded a bell-shaped dose-response curve for PMA (phorbol 12-myristate 13-acetate)-stimulated O₂⁻ generation: (1) 0.1–1 ng/mL V. vulnificus LPS enhanced O₂⁻ generation significantly but with limited inflammatory mediator generation; (2) 10–100 ng/mL V. vulnificus LPS maximized O₂⁻ generation with concomitant release of thromboxane B₂ (TXB₂), matrix metalloproteinase-9 (MMP-9), and several cytokines and chemokines; (3) 1000–100,000 ng/mL V. vulnificus LPS, with the exception of TXB₂, yielded both attenuated O₂⁻ production, and a progressive decrease in MMP-9, cytokines and chemokines investigated. Thus concentration-dependent treatment of neonatal brain microglia with V. vulnificus MO6-24/O LPS resulted in a significant rise in O₂⁻ production, followed by a progressive decrease in O₂⁻ release, with concomitant release of lactic dehydrogenase (LDH), and generation of TXB₂, MMP-9, cytokines and chemokines. We hypothesize that the inflammatory mediators investigated may be cytotoxic to microglia in vitro, by an as yet undetermined autocrine mechanism. Although V. vulnificus LPS was less potent than E. coli LPS in vitro, inflammatory mediator release by the former was clearly more efficacious. Finally, we hypothesize that should V. vulnificus LPS gain entry into the CNS, it would be possible that microglia might become activated, resulting in high levels of O₂⁻ as well as neuroinflammatory TXB₂, MMP-9, cytokines and chemokines.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.