Tempol, an intracellular antioxidant, inhibits tissue factor expression, attenuates dendritic cell function, and is partially protective in a murine model of cerebral malaria.

Bibliographic Details
Title: Tempol, an intracellular antioxidant, inhibits tissue factor expression, attenuates dendritic cell function, and is partially protective in a murine model of cerebral malaria.
Authors: Ivo M B Francischetti, Emile Gordon, Bruna Bizzarro, Nidhi Gera, Bruno B Andrade, Fabiano Oliveira, Dongying Ma, Teresa C F Assumpção, José M C Ribeiro, Mirna Pena, Chen-Feng Qi, Ababacar Diouf, Samuel E Moretz, Carole A Long, Hans C Ackerman, Susan K Pierce, Anderson Sá-Nunes, Michael Waisberg
Source: PLoS ONE, Vol 9, Iss 2, p e87140 (2014)
Publisher Information: Public Library of Science (PLoS), 2014.
Publication Year: 2014
Collection: LCC:Medicine
LCC:Science
Subject Terms: Medicine, Science
More Details: BackgroundThe role of intracellular radical oxygen species (ROS) in pathogenesis of cerebral malaria (CM) remains incompletely understood.Methods and findingsWe undertook testing Tempol--a superoxide dismutase (SOD) mimetic and pleiotropic intracellular antioxidant--in cells relevant to malaria pathogenesis in the context of coagulation and inflammation. Tempol was also tested in a murine model of CM induced by Plasmodium berghei Anka infection. Tempol was found to prevent transcription and functional expression of procoagulant tissue factor in endothelial cells (ECs) stimulated by lipopolysaccharide (LPS). This effect was accompanied by inhibition of IL-6, IL-8, and monocyte chemoattractant protein (MCP-1) production. Tempol also attenuated platelet aggregation and human promyelocytic leukemia HL60 cells oxidative burst. In dendritic cells, Tempol inhibited LPS-induced production of TNF-α, IL-6, and IL-12p70, downregulated expression of co-stimulatory molecules, and prevented antigen-dependent lymphocyte proliferation. Notably, Tempol (20 mg/kg) partially increased the survival of mice with CM. Mechanistically, treated mice had lowered plasma levels of MCP-1, suggesting that Tempol downmodulates EC function and vascular inflammation. Tempol also diminished blood brain barrier permeability associated with CM when started at day 4 post infection but not at day 1, suggesting that ROS production is tightly regulated. Other antioxidants-such as α-phenyl N-tertiary-butyl nitrone (PBN; a spin trap), MnTe-2-PyP and MnTBAP (Mn-phorphyrin), Mitoquinone (MitoQ) and Mitotempo (mitochondrial antioxidants), M30 (an iron chelator), and epigallocatechin gallate (EGCG; polyphenol from green tea) did not improve survival. By contrast, these compounds (except PBN) inhibited Plasmodium falciparum growth in culture with different IC50s. Knockout mice for SOD1 or phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (gp91(phox-/-)) or mice treated with inhibitors of SOD (diethyldithiocarbamate) or NADPH oxidase (diphenyleneiodonium) did not show protection or exacerbation for CM.ConclusionResults with Tempol suggest that intracellular ROS contribute, in part, to CM pathogenesis. Therapeutic targeting of intracellular ROS in CM is discussed.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1932-6203
Relation: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0087140&type=printable; https://doaj.org/toc/1932-6203
DOI: 10.1371/journal.pone.0087140&type=printable
DOI: 10.1371/journal.pone.0087140
Access URL: https://doaj.org/article/93b898ae10464641b2643a37ba809973
Accession Number: edsdoj.93b898ae10464641b2643a37ba809973
Database: Directory of Open Access Journals
More Details
ISSN:19326203
DOI:10.1371/journal.pone.0087140&type=printable
Published in:PLoS ONE
Language:English