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Chen W, Colon R, Louda JW, Del Rey FR, Durham M, Rein KS. Brevetoxin (PbTx-2) influences the redox status and NPQ of Karenia brevis by way of thioredoxin reductase. Harmful Algae 2018; 71:29-39. [PMID: 29306394 PMCID: PMC5994908 DOI: 10.1016/j.hal.2017.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 11/18/2017] [Accepted: 11/18/2017] [Indexed: 06/07/2023]
Abstract
The Florida red tide dinoflagellate, Karenia brevis, is the major harmful algal bloom dinoflagellate of the Gulf of Mexico and plays a destructive role in the region. Blooms of K. brevis can produce brevetoxins: ladder-shaped polyether (LSP) compounds, which can lead to adverse human health effects, such as reduced respiratory function through inhalation exposure, or neurotoxic shellfish poisoning through consumption of contaminated shellfish. The endogenous role of the brevetoxins remains uncertain. Recent work has shown that some forms of NADPH dependent thioredoxin reductase (NTR) are inhibited by brevetoxin-2 (PbTx-2). The study presented herein reveals that high toxin and low toxin K. brevis, which have a ten-fold difference in toxin content, also show a significant difference in their ability, not only to produce brevetoxin, but also in their cellular redox status and distribution of xanthophyll cycle pigments. These differences are likely due to the inhibition of NTR by brevetoxin. The work could shed light on the physiological role that brevetoxin fills for K. brevis.
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Affiliation(s)
- Wei Chen
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8thStreet, Miami, FL 33199, United States.
| | - Ricardo Colon
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8thStreet, Miami, FL 33199, United States.
| | - J William Louda
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 United States.
| | - Freddy Rodriguez Del Rey
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8thStreet, Miami, FL 33199, United States.
| | - Michaella Durham
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8thStreet, Miami, FL 33199, United States.
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8thStreet, Miami, FL 33199, United States.
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Chen W, Tuladhar A, Rolle S, Lai Y, Rodriguez Del Rey F, Zavala CE, Liu Y, Rein KS. Brevetoxin-2, is a unique inhibitor of the C-terminal redox center of mammalian thioredoxin reductase-1. Toxicol Appl Pharmacol 2017; 329:58-66. [PMID: 28551108 DOI: 10.1016/j.taap.2017.05.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/15/2017] [Accepted: 05/22/2017] [Indexed: 11/15/2022]
Abstract
Karenia brevis, the Florida red tide dinoflagellate produces a suite of neurotoxins known as the brevetoxins. The most abundant of the brevetoxins PbTx-2, was found to inhibit the thioredoxin-thioredoxin reductase system, whereas the PbTx-3 has no effect on this system. On the other hand, PbTx-2 activates the reduction of small disulfides such as 5,5'-dithio-bis-(2-nitrobenzoic acid) by thioredoxin reductase. PbTx-2 has an α, β-unsaturated aldehyde moiety which functions as an efficient electrophile and selenocysteine conjugates are readily formed. PbTx-2 blocks the inhibition of TrxR by the inhibitor curcumin, whereas curcumin blocks PbTx-2 activation of TrxR. It is proposed that the mechanism of inhibition of thioredoxin reduction is via the formation of a Michael adduct between selenocysteine and the α, β-unsaturated aldehyde moiety of PbTx-2. PbTx-2 had no effect on the rates of reactions catalyzed by related enzymes such as glutathione reductase, glutathione peroxidase or glutaredoxin.
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Affiliation(s)
- Wei Chen
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Anupama Tuladhar
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Shantelle Rolle
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Yanhao Lai
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Freddy Rodriguez Del Rey
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Cristian E Zavala
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Yuan Liu
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States; Biomolecular Sciences Institute, School of Integrated Sciences and Humanity, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States.
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