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Title: Troglitazone induces differentiation in Trypanosoma brucei

Abstract

Trypanosoma brucei, a protozoan parasite causing sleeping sickness, is transmitted by the tsetse fly and undergoes a complex lifecycle including several defined stages within the insect vector and its mammalian host. In the latter, differentiation from the long slender to the short stumpy form is induced by a yet unknown factor of trypanosomal origin. Here we describe that some thiazolidinediones are also able to induce differentiation. In higher eukaryotes, thiazolidinediones are involved in metabolism and differentiation processes mainly by binding to the intracellular receptor peroxisome proliferator activated receptor {gamma}. Our studies focus on the effects of troglitazone on bloodstream form trypanosomes. Differentiation was monitored using mitochondrial markers (membrane potential, succinate dehydrogenase activity, inhibition of oxygen uptake by KCN, amount of cytochrome transcripts), morphological changes (Transmission EM and light microscopy), and transformation experiments (loss of the Variant Surface Glycoprotein coat and increase of dihydroliponamide dehydrogenase activity). To further investigate the mechanisms responsible for these changes, microarray analyses were performed, showing an upregulation of expression site associated gene 8 (ESAG8), a potential differentiation regulator.

Authors:
 [1];  [1];  [1];  [2];  [2];  [3];  [2];  [4]
  1. Interfakultaeres Institut fuer Biochemie, Universitaet Tuebingen, Hoppe-Seyler-Str. 4, D-72076 Tuebingen (Germany)
  2. Functional Genome Analysis, DKFZ, D-69120 Heidelberg (Germany)
  3. Institut fuer Physiologie, Gmelinstr. 5, D-72076 Tuebingen (Germany)
  4. Interfakultaeres Institut fuer Biochemie, Universitaet Tuebingen, Hoppe-Seyler-Str. 4, D-72076 Tuebingen (Germany). E-mail: michael.duszenko@uni-tuebingen.de
Publication Date:
OSTI Identifier:
20972155
Resource Type:
Journal Article
Resource Relation:
Journal Name: Experimental Cell Research; Journal Volume: 313; Journal Issue: 9; Other Information: DOI: 10.1016/j.yexcr.2007.03.003; PII: S0014-4827(07)00115-2; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; GENE REGULATION; GLOSSINA; GLYCOPROTEINS; METABOLISM; MICROSCOPY; MITOCHONDRIA; MORPHOLOGICAL CHANGES; RECEPTORS; TRYPANOSOMA; TRYPANOSOMES; VECTORS

Citation Formats

Denninger, Viola, Figarella, Katherine, Schoenfeld, Caroline, Brems, Stefanie, Busold, Christian, Lang, Florian, Hoheisel, Joerg, and Duszenko, Michael. Troglitazone induces differentiation in Trypanosoma brucei. United States: N. p., 2007. Web. doi:10.1016/j.yexcr.2007.03.003.
Denninger, Viola, Figarella, Katherine, Schoenfeld, Caroline, Brems, Stefanie, Busold, Christian, Lang, Florian, Hoheisel, Joerg, & Duszenko, Michael. Troglitazone induces differentiation in Trypanosoma brucei. United States. doi:10.1016/j.yexcr.2007.03.003.
Denninger, Viola, Figarella, Katherine, Schoenfeld, Caroline, Brems, Stefanie, Busold, Christian, Lang, Florian, Hoheisel, Joerg, and Duszenko, Michael. Tue . "Troglitazone induces differentiation in Trypanosoma brucei". United States. doi:10.1016/j.yexcr.2007.03.003.
@article{osti_20972155,
title = {Troglitazone induces differentiation in Trypanosoma brucei},
author = {Denninger, Viola and Figarella, Katherine and Schoenfeld, Caroline and Brems, Stefanie and Busold, Christian and Lang, Florian and Hoheisel, Joerg and Duszenko, Michael},
abstractNote = {Trypanosoma brucei, a protozoan parasite causing sleeping sickness, is transmitted by the tsetse fly and undergoes a complex lifecycle including several defined stages within the insect vector and its mammalian host. In the latter, differentiation from the long slender to the short stumpy form is induced by a yet unknown factor of trypanosomal origin. Here we describe that some thiazolidinediones are also able to induce differentiation. In higher eukaryotes, thiazolidinediones are involved in metabolism and differentiation processes mainly by binding to the intracellular receptor peroxisome proliferator activated receptor {gamma}. Our studies focus on the effects of troglitazone on bloodstream form trypanosomes. Differentiation was monitored using mitochondrial markers (membrane potential, succinate dehydrogenase activity, inhibition of oxygen uptake by KCN, amount of cytochrome transcripts), morphological changes (Transmission EM and light microscopy), and transformation experiments (loss of the Variant Surface Glycoprotein coat and increase of dihydroliponamide dehydrogenase activity). To further investigate the mechanisms responsible for these changes, microarray analyses were performed, showing an upregulation of expression site associated gene 8 (ESAG8), a potential differentiation regulator.},
doi = {10.1016/j.yexcr.2007.03.003},
journal = {Experimental Cell Research},
number = 9,
volume = 313,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • Trypanosomes use trans splicing to place a common 39-nucleotide spliced-leader sequence on the 5' ends of all of their mRNAs. To identify likely participants in this reaction, the authors used antiserum directed against the characteristic U RNA 2,2,7-trimehtylguanosine (TMG) cap to immunoprecipitate six candidate U RNAs from total trypanosome RNA. Genomic Southern analysis using oligonucleotide probes constructed frm partial RNA sequence indicated that the four largest RNAs (A through D) are encoded by single-copy genes that are not closely linked to one another. The authors have cloned and sequenced these genes, mapped the 5' ends of the encoded RNAs,and identifiedmore » three of the RNAs as the trypanosome U2, U4, and U6 analogs by virtue of their sequences and structural homologies with the corresponding metazoan U RNAs. The fourth RNA, RNA B (144 nucleotides), was not sufficiently similar to known U RNAs to allow them to propose an identity. Surprisingly, none of the U RNAs contained the consensus Sm antigen-binding site, a feature totally conserved among several classes of U RNAs, including U2 and U4. Similarly, the sequence of the U2 RNA region shown to be involved in pre-mRNA branchpoint recognition in yeast, and exactly conserved in metazoan U2 RNAs, was totally divergent in trypanosomes. Like all other U6 RNAs, trypanosome U6 did not contain a TMG cap and was immunoprecipitated from deproteinized RNA by anti-TMG antibody because of its association with the TMG-capped U4 RNA. These two RNAs contained extensive regions of sequence complementarity which phylogenetically support the secondary-structure model proposed by D.A. Brow and C. Guthrie (Nature (London) 334:213-218, 1988) for the organization of the analogous yeast U4-U6 complex.« less
  • The variant surface glycoproteins (VSGs) of Trypanosoma brucei are synthesized with a hydrophobic COOH-terminal peptide that is cleaved and replaced by a glycophospholipid, which anchors VSG to the surface membrane. The kinetics of VSG processing were studied by metabolic labeling with (/sup 35/S)methionine and (/sup 3/H)myristic acid. The COOH-terminal oligosaccharide-containing structure remaining after phospholipase removal of dimyristyl glycerol from membrane-form VSG could be detected serologically within 1 min of polypeptide synthesis in two T. brucei variants studied. Addition of the oligosaccharide-containing structure was resistant to tunicamycin. VSGs synthesized in the presence of tunicamycin displayed lower apparent molecular weights, consistent withmore » the complete inhibition of N-glycosylation at one (variant 117), two (variant 221), or at least three (variant 118) internal asparagine sites. In dual-labeling studies, cycloheximide caused rapid inhibition of both (/sup 35/S)methionine and (/sup 3/H)myristic acid incorporation.« less
  • It was shown that irradiation (650 rad) of 7 inbred strains of mice did not block the ability of Trypanosoma brucei rhodesiense to transform from the long slender (LS) to the short stumpy (SS) form or alter the plateau in parasitemia. In addition, it was observed that significant differences in parasitemia levels, in the rate of transformation from the LS to the SS form, as well as in the survival times occurred between the irradiated C3HeB/FeJ and several of the other strains. These differences in the nonspecific ability to control parasitemia appeared to be characteristic for each inbred strain ofmore » mice. The resistant strains generally had lower parasitemia than the susceptible strains. However, it was also shown that there is not a one-to-one correlation between the innate ability of a mouse strain to control its initial parasitemia, and the strain's ability to clear the parasitemia or increase its survival time. It was therefore concluded that the hypothesis which states that the ability of an animal to increase nonspecifically the rate of transformation, and therefore to lower the parasitemia, allowing intact animals to respond immunologically and survive longer is either incorrect or incomplete. The results further show that the ability of mice to clear their initial parasitemia by an antibody response is not necessarily correlated with their survival time. Therefore, this study suggests that factors other than an antibody response and the nonspecific control of parasitemia are important in resistance.« less
  • No abstract prepared.