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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Biological Implications of Selenium and its Role in Trypanosomiasis Treatment

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Author(s):
da Silva, M. T. A. [1] ; Silva-Jardim, I. [2] ; Thiemann, O. H. [1]
Total Authors: 3
Affiliation:
[1] IFSC USP, Lab Prot Crystallog & Struct Biol, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Estadual Santa Cruz, Dept Ciencias Biol, BR-45662900 Ilheus, BA - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Current Medicinal Chemistry; v. 21, n. 15, p. 1772-1780, MAY 2014.
Web of Science Citations: 12
Abstract

Selenium (Se) is an essential trace element for several organisms and is present in proteins as selenocysteine (Sec or U), an amino acid that is chemically distinct from serine and cysteine by a single atom (Se instead of O or S, respectively). Sec is incorporated into selenoproteins at an in-frame UGA codon specified by an mRNA stem-loop structure called the selenocysteine incorporating sequence (SECIS) presented in selenoprotein mRNA and specific selenocysteine synthesis and incorporation machinery. Selenoproteins are presented in all domains but are not found in all organisms. Although several functions have been attributed to this class, the majority of the proteins are involved in oxidative stress defense. Here, we discuss the kinetoplastid selenocysteine pathway and how selenium supplementation is able to alter the infection course of trypanosomatids in detail. These organisms possess the canonical elements required for selenoprotein production such as phosphoseryl tRNA kinase (PSTK), selenocysteine synthase (SepSecS), selenophosphase synthase (SelD or SPS), and elongation factor EFSec (SelB), whereas other important factors presented in mammal cells, such as SECIS binding protein 2 (SBP) and SecP 43, are absent. The selenoproteome of trypanosomatids is small, as is the selenoproteome of others parasites, which is in contrast to the large number of selenoproteins found in bacteria, aquatic organisms and higher eukaryotes. Trypanosoma and Leishmania are sensitive to auranofin, a potent selenoprotein inhibitor; however, the probable drug mechanism is not related to selenoproteins in kinetoplastids. Selenium supplementation decreases the parasitemia of various Trypanosome infections and reduces important parameters associated with diseases such as anemia and parasite-induced organ damage. New experiments are necessary to determine how selenium acts, but evidence suggests that immune response modulation and increased host defense against oxidative stress contribute to control of the parasite infection. (AU)

FAPESP's process: 11/24017-4 - Study of selenium metabolism in primitive eukaryotes
Grantee:Marco Túlio Alves da Silva
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 98/14138-2 - Center for Structural Molecular Biotechnology
Grantee:Glaucius Oliva
Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC