88 results on '"Soteriadou, K."'
Search Results
2. Indirubin analogues inhibit trypanosoma brucei glycogen synthase kinase 3 short and T. Brucei growth
- Author
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Efstathiou, A. Gaboriaud-Kolar, N. Myrianthopoulos, V. Vougogiannopoulou, K. Subota, I. Aicher, S. Mikros, E. Bastin, P. Skaltsounis, A.-L. Soteriadou, K. Smirlis, D.
- Abstract
The protozoan parasite Trypanosoma brucei is the causative agent of human African trypanosomiasis (HAT). The disease is fatal if it remains untreated, whereas most drug treatments are inadequate due to high toxicity, difficulties in administration, and low central nervous system penetration. T. brucei glycogen synthase kinase 3 short (TbGSK3s) is essential for parasite survival and thus represents a potential drug target that could be exploited for HAT treatment. Indirubins, effective leishmanicidals, provide a versatile scaffold for the development of potent GSK3 inhibitors. Herein, we report on the screening of 69 indirubin analogues against T. brucei bloodstream forms. Of these, 32 compounds had potent antitrypanosomal activity (half-maximal effective concentration 0.050 to 3.2 M) and good selectivity for the analogues over human HepG2 cells (range, 7.4- to over 641-fold). The majority of analogues were potent inhibitors of TbGSK3s, and correlation studies for an indirubin subset, namely, the 6-bromosubstituted 3=-oxime bearing an extra bulky substituent on the 3= oxime [(6-BIO-3=-bulky)-substituted indirubins], revealed a positive correlation between kinase inhibition and antitrypanosomal activity. Insights into this indirubin-TbGSK3s interaction were provided by structure-activity relationship studies. Comparison between 6-BIO-3=-bulky-substituted indirubin-treated parasites and parasites silenced for TbGSK3s by RNA interference suggested that the above-described compounds may target TbGSK3s in vivo. To further understand the molecular basis of the growth arrest brought about by the inhibition or ablation of TbGSK3s, we investigated the intracellular localization of TbGSK3s. TbGSK3s was present in cytoskeletal structures, including the flagellum and basal body area. Overall, these results give insights into the mode of action of 6-BIO-3=-bulky-substituted indirubins that are promising hits for antitrypanosomal drug discovery. Copyright © 2019 American Society for Microbiology. All Rights Reserved.
- Published
- 2019
3. Identification of the first pyrimidine nucleobase transporter in Leishmania: similarities with the Trypanosoma brucei U1 transporter and antileishmanial activity of uracil analogues
- Author
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PAPAGEORGIOU, I. G., YAKOB, L., AL SALABI, M. I., DIALLINAS, G., SOTERIADOU, K. P., and DE KONING, H. P.
- Published
- 2005
4. Structural profile of SRYD-containing peptide analogues of Leishmania gp63 adhesion site
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Tsikaris, V., primary, Mayomi, A. O., additional, Sakarellos-Daitsiotis, M., additional, Sakarellos, C., additional, Cung, M. T., additional, Tzinia, A. K., additional, and Soteriadou, K., additional
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- 1995
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5. Conformational study on a fibronectin-like sequence (250–257) of Leishmania gp63, using 1H-NMR spectroscopy
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Tsikaris, V., primary, Sakarellos-Daitsiotis, M., additional, Sakarellos, C., additional, Cung, M. T., additional, Tzinia, A. K., additional, and Soteriadou, K. P., additional
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- 1994
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6. Leishmania Antigens Probed by Monoclonal Antibodies to Leishmania Membrane and to Acetylcholine Receptor
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Soteriadou, K. Ph., Tzinia, A. K., Hadziantoniou, M. G., Tzartos, S. J., Chang, K.-P., editor, and Snary, David, editor
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- 1987
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7. Common Antigenic Determinants between Acetylcholine Receptor and Protozoan Membranes
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Soteriadou, K., Tzinia, A., Tzartos, S., and Maelicke, Alfred, editor
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- 1986
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8. An inhibitor-driven study for enhancing the selectivity of indirubin derivatives towards leishmanial Glycogen Synthase Kinase-3 over leishmanial cdc2-related protein kinase 3
- Author
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Efstathiou, A. Gaboriaud-Kolar, N. Smirlis, D. Myrianthopoulos, V. Vougogiannopoulou, K. Alexandratos, A. Kritsanida, M. Mikros, E. Soteriadou, K. Skaltsounis, A.-L.
- Abstract
Background: In search of new antiparasitic agents for overcoming the limitations of current leishmaniasis chemotherapy, we have previously shown that 6-bromoindirubin-3'-oxime (6BIO) and several other 6-substituted analogues of indirubin, a naturally occurring bis-indole present in mollusks and plants, displayed reverse selectivity from the respective mammalian kinases, targeting more potently the leishmanial Cyclin-Dependent Kinase-1 (CDK1) homologue [cdc2-related protein kinase 3 (LCRK3)] over leishmanial Glycogen Synthase Kinase-3 (LGSK-3). This reversal of selectivity in Leishmania parasites compared to mammalian cells makes the design of specific indirubin-based LGSK-3 inhibitors difficult. In this context, the identification of compounds bearing specific substitutions that shift indirubin inhibition towards LGSK-3, previously found to be a potential drug target, over LCRK3 is imperative for antileishmanial targeted drug discovery. Methods. A new in-house indirubin library, composed of 35 compounds, initially designed to target mammalian kinases (CDKs, GSK-3), was tested against Leishmania donovani promastigotes and intracellular amastigotes using the Alamar blue assay. Indirubins with antileishmanial activity were tested against LGSK-3 and LCRK3 kinases, purified from homologous expression systems. Flow cytometry (FACS) was used to measure the DNA content for cell-cycle analysis and the mode of cell death. Comparative structural analysis of the involved kinases was then performed using the Szmap algorithm. Results: We have identified 7 new indirubin analogues that are selective inhibitors of LGSK-3 over LCRK3. These new inhibitors were also found to display potent antileishmanial activity with GI50 values of
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- 2014
9. The assessment of genetic polymorphisms and their potential association with aspirin resistance in a population of Greek patients with acute coronary syndrome
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Gouzelou, E., primary, Tsoumani, M.E., additional, Ntalas, I.V., additional, Efstathiou, A., additional, Smirlis, D., additional, Goudevenos, I.A., additional, Tselepis, A.D., additional, and Soteriadou, K., additional
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- 2015
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10. Targeting essential pathways in trypanosomatids gives insights into protozoan mechanisms of cell death
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Smirlis, D., Duszenko, M., Ruiz, A.J., Scoulica, E., Bastien, P., Fasel, N., and Soteriadou, K.
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fungi ,parasitic diseases - Abstract
Apoptosis is a normal component of the development and health of multicellular organisms. However, apoptosis is now considered a prerogative of unicellular organisms, including the trypanosomatids of the genera Trypanosoma spp. and Leishmania spp., causative agents of some of the most important neglected human diseases. Trypanosomatids show typical hallmarks of apoptosis, although they lack some of the key molecules contributing to this process in metazoans, like caspase genes, Bcl-2 family genes and the TNF-related family of receptors. Despite the lack of these molecules, trypanosomatids appear to have the basic machinery to commit suicide. The components of the apoptotic execution machinery of these parasites are slowly coming into light, by targeting essential processes and pathways with different apoptogenic agents and inhibitors. This review will be confined to the events known to drive trypanosomatid parasites to apoptosis.
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- 2010
11. Identification of indirubin derivatives as anti-trypanosomal agents
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Vougogiannopoulou, K, primary, Gaboriaud-Kolar, N, additional, Efstathiou, A, additional, Soteriadou, K, additional, Smirlis, D, additional, and Skaltsounis, L, additional
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- 2014
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12. 6-Br-5methylindirubin-3′oxime (5-Me-6-BIO) targeting the leishmanial glycogen synthase kinase-3 (GSK-3) short form affects cell-cycle progression and induces apoptosis-like death: Exploitation of GSK-3 for treating leishmaniasis
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Xingi, E. Smirlis, D. Myrianthopoulos, V. Magiatis, P. Grant, K.M. Meijer, L. Mikros, E. Skaltsounis, A.-L. Soteriadou, K.
- Abstract
Indirubins known to target mammalian cyclin-dependent kinases (CDKs) and glycogen synthase kinase (GSK-3) were tested for their antileishmanial activity. 6-Br-indirubin-3′-oxime (6-BIO), 6-Br-indirubin-3′acetoxime and 6-Br-5methylindirubin-3′oxime (5-Me-6-BIO) were the most potent inhibitors of Leishmania donovani promastigote and amastigote growth (half maximal inhibitory concentration (IC50) values ≤1.2 μM). Since the 6-Br substitution on the indirubin backbone greatly enhances the selectivity for mammalian GSK-3 over CDKs, we identified the leishmanial GSK-3 homologues, a short (LdGSK-3s) and a long one, focusing on LdGSK-3s which is closer to human GSK-3β, for further studies. Kinase assays showed that 5-Me-6-BIO inhibited LdGSK-3s more potently than CRK3 (the CDK1 homologue in Leishmania), whilst 6-BIO was more selective for CRK3. Promastigotes treated with 5-Me-6-BIO accumulated in the S and G2/M cell-cycle phases and underwent apoptosis-like death. Interestingly, these phenotypes were completely reversed in parasites over-expressing LdGSK-3s. This finding strongly supports that LdGSK-3s is: (i) the intracellular target of 5-Me-6-BIO, and (ii) involved in cell-cycle control and in pathways leading to apoptosis-like death. 6-BIO treatment induced a G2/M arrest, consistent with inhibition of CRK3 and apoptosis-like death. These effects were partially reversed in parasites over-expressing LdGSK-3s suggesting that in vivo 6-BIO may also target LdGSK-3s. Molecular docking of 5-Me-6-BIO in CRK3 and 6-BIO in human GSK-3β and LdGSK-3s active sites predict the existence of functional/structural differences that are sufficient to explain the observed difference in their affinity. In conclusion, LdGSK-3s is validated as a potential drug target in Leishmania and could be exploited for the development of selective indirubin-based leishmanicidals. © 2009 Australian Society for Parasitology Inc.
- Published
- 2009
13. Development and biochemical characterization of new specific reagents for the detection and isolation of cardiac troponins
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Strongylis, C., Papadopoulos, C., Iaka, E. K., Soteriadou, K., Michalis, L. K., and Tsikaris, V.
- Abstract
Journal of Peptide Science
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- 2008
14. Kinetic and mutational analysis of the Trypanosoma brucei NBT1 nucleobase transporter expressed in Saccharomyces cerevisiae reveals structural similarities between ENT and MFS transporters
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Papageorgiou, I. De Koning, H.P. Soteriadou, K. Diallinas, G.
- Abstract
Parasitic protozoa are unable to synthesise purines de novo and thus depend on the uptake of nucleosides and nucleobases across their plasma membrane through specific transporters. A number of nucleoside and nucleobase transporters from Trypanosoma brucei brucei and Leishmania major have recently been characterised and shown to belong to the equilibrative nucleoside transporter (ENT) family. A number of studies have demonstrated the functional importance of particular transmembrane segments (TMS) in nucleoside-specific ENT proteins. TbNBT1, one of only three bona fide nucleobase-selective members of the ENT family, has previously been shown to be a high-affinity transporter for purine nucleobases and guanosine. In this study, we use the Saccharomyces cerevisiae expression system to build a biochemical model of how TbNBT1 recognises nucleobases. We next performed random in vitro and site-directed mutagenesis to identify residues critical for TbNBT1 function. The identification of residues likely to contribute to permeant binding, when combined with a structural model of TbNBT1 obtained by homology threading, yield a tentative three-dimensional model of the transporter binding site that is consistent with the binding model emerging from the biochemical data. The model strongly suggests the involvement of TMS5, TMS7 and TMS8 in TbNBT1 function. This situation is very similar to that concerning transporters of the major facilitator superfamily (MFS), one of which was used as a template for the threading. This point raises the possibility that ENT and MFS carriers, despite being considered evolutionarily distinct, might in fact share similar topologies and substrate translocations pathways. © 2007 Australian Society for Parasitology Inc.
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- 2008
15. Spread of vector-borne diseases and neglect of leishmaniasis, Europe
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Dujardin J.-C., Campino L., Cañavate C., Dedet J.-P., Gradoni L., Soteriadou K., Mazeris A., Ozbel Y., Boelaert M., and Ege Üniversitesi
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ComputingMilieux_MANAGEMENTOFCOMPUTINGANDINFORMATIONSYSTEMS ,ComputingMethodologies_PATTERNRECOGNITION ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,InformationSystems_MISCELLANEOUS - Abstract
PubMed ID: 18598618, The risk for reintroduction of some exotic vector-borne diseases in Europe has become a hot topic, while the reality of others is neglected at the public health policy level. Leishmaniasis is endemic in all southern countries of Europe, with ?700 autochthonous human cases reported each year (3,950 if Turkey is included). Asymptomatic cases have been estimated at 30-100/1 symptomatic case, and leishmaniasis has up to 25% seroprevalence in domestic dogs. Even though leishmaniasis is essentially associated with Leishmania infantum and visceral leishmaniasis, new species, such as L. donovani and L. tropica, might colonize European sand fly vectors. Drug-resistant L. infantum strains might be exported outside Europe through dogs. Despite this possibility, no coordinated surveillance of the disease exists at the European level. In this review of leishmaniasis importance in Europe, we would like to bridge the gap between research and surveillance and control.
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- 2008
16. In vitro activity of 10-deacetylbaccatin III against Leishmania donovani promastigotes and intracellular amastigotes
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Georgopoulou, K. Smirlis, D. Bisti, S. Xingi, E. Skaltsounis, L. Soteriadou, K.
- Abstract
Current treatments for leishmaniasis are unsatisfactory due to their route of administration, toxicity and expense but, most importantly, to the developed resistance of Leishmania to first-line drugs. Therefore, the identification of new effective targeted drugs is an urgent need. Since many studies have shown that medicinal plants contain compounds active against protozoa we have undertaken a study aiming to determine the antileishmanial activity of the taxoid 10-deacetylbaccatin III, isolated from dried needles and small branches of the European yew tree (Taxus baccata). Interestingly, 10-deacetylbaccatin III was found to selectively inhibit the growth of L donovani intracellular amastigotes within J774 murine macrophages in vitro at nanomolar concentrations with an IC50 value of 70 nM. Concentrations of 10-deacetylbaccatin III as high as 5 μM did not affect J774 murine macrophages whereas 20 nM of taxol, used as a control, was toxic to macrophages. The compound also inhibited the growth of L. donovani promastigotes but at higher concentrations with a maximum level of inhibition of 35%. Taxol inhibited promastigote growth at micromolar concentrations. Comparison of the effect of 10-deacetylbaccatin III to that of taxol on cell cycle progression and cellular morphology showed that their mechanisms of action are different. The 10-deacetylbaccatin III-treated promastigotes were slightly arrested in the G2/M phase whereas taxol-treated cells were blocked in the G2/M phase. In addition 10-deacetylbaccatin III treatment, contrary to taxol, did not affect cellular morphology. © Georg Thieme Verlag KG Stuttgart.
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- 2007
17. Cardiac troponins derived conjugates as tools for producing specific antibodies: Synthesis and immune response
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Strongylis, C., Papadopoulos, C., Naka, K., Michalis, L., Soteriadou, K., and Tsikaris, V.
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Journal of Peptide Science
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- 2006
18. Effect of synthetic peptides corresponding to residues 313-332 of the alpha(IIb) subunit on platelet activation and fibrinogen binding to alpha(IIb)beta(3)
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Mitsios, J. V., Tambaki, A. P., Abatzis, M., Biris, N., Sakarellos-Daitsiotis, M., Sakarellos, C., Soteriadou, K., Goudevenos, J., Elisaf, M., Tsoukatos, D., Tsikaris, V., and Tselepis, A. D.
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integrin alpha(iib)beta(3) ,ligand-binding ,receptor ,domain ,aggregation ,integrin inhibitors ,gamma-chain ,platelet activation inhibitors ,sequence ,glycoprotein-iib-iiia ,peptides ,site ,alpha(iib)beta(3) receptor ,recognition - Abstract
The platelet integrin receptor alpha(IIb)beta(3) plays a critical role in thrombosis and haemostasis by mediating interactions between platelets and several ligands but primarily fibrinogen. It has been shown previously that the YMESRADR KLAEVGRVYLFL (313-332) sequence of the alpha(IIb) subunit plays an important role in platelet activation, fibrinogen binding and alpha(IIb)beta(3)-mediated outside-in signalling. Furthermore, we recently showed that the 20-residue peptide (20-mer) alpha(IIb) 313-332, is a potent inhibitor of platelet aggregation and fibrinogen binding to alpha(IIb)beta(3), interacting with fibrinogen rather than the receptor. In an effort to determine the sequence and the minimum length required for the biological activity of the above 20-mer, we synthesized seven octapeptides, each overlapping by six residues, covering the entire sequence and studied their effect on platelet activation as well as fibrinogen binding to activated platelets. We show for the first time that octapeptides containing the RAD sequence are capable of inhibiting platelet aggregation and secretion as well as fibrinogen binding to the activated alpha(IIb)beta(3), possibly interacting with the ligand rather than the receptor. This suggests that the RAD sequence, common to all the inhibitory peptides, is critical for their biological activity. However, the presence of the YMES sequence, adjacent to RAD, significantly increases the peptide's biological potency. The development of such inhibitors derived from the 313-332 region of the alpha(IIb) subunit may be advantageous against the RGD-like antagonists as they could inhibit platelet activation without interacting with alpha(IIb)beta(3), thus failing to further induce alpha(IIb)beta(3)-mediated outside-in signalling. European Journal of Biochemistry
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- 2004
19. Mapping the binding domains of the alpha(IIb) subunit. A study performed on the activated form of the platelet integrin alpha(IIb)beta(3)
- Author
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Biris, N., Abatzis, M., Mitsios, J. V., Sakarellos-Daitsiotis, M., Sakarellos, C., Tsoukatos, D., Tselepis, A. D., Michalis, L., Sideris, D., Konidou, G., Soteriadou, K., and Tsikaris, V.
- Subjects
rgd ,Blood Platelets/*chemistry/*metabolism ,Molecular Sequence Data ,cell-adhesion ,alpha(iib)-binding domains ,Mice ,Platelet Aggregation/drug effects/*physiology ,fibrinogen receptor ,glanzmanns-thrombasthenia ,Platelet Aggregation Inhibitors/pharmacology ,alpha(iib) mapping ,ligand recognition ,Animals ,Humans ,Platelet Glycoprotein GPIIb-IIIa Complex/*chemistry/genetics/*metabolism ,Amino Acid Sequence ,Protein Phosphatase 2 ,Adenosine Diphosphate/pharmacology ,Amino Acid Motifs/genetics ,Mice, Inbred BALB C ,Binding Sites ,Dose-Response Relationship, Drug ,Dual Specificity Phosphatase 2 ,integrin inhibitors ,Fluorescein/chemistry ,platelet-aggregation inhibitors ,glycoprotein-iib-iiia ,Protein Structure, Tertiary ,Protein Subunits ,recognition site ,Antibodies, Monoclonal/metabolism ,Fibrinogen/chemistry/drug effects/metabolism ,synthetic peptides ,alpha(iib)beta(3) receptor ,monoclonal-antibody ,Platelet Activation/drug effects/physiology ,gpiib-iiia ,Peptides/chemical synthesis/metabolism/pharmacology ,Protein Binding ,Protein Tyrosine Phosphatases/drug effects/metabolism - Abstract
alpha(IIb)beta(3), a member of the integrin family of adhesive protein receptors, is the most abundant glycoprotein on platelet plasma-membranes and binds to adhesive proteins via the recognition of short amino acid sequences, for example the ubiquitous RGD motif. However, elucidation of the ligand-binding domains of the receptor remains controversial, mainly owing to the fact that integrins are conformationally labile during purification and storage. In this study, a detailed mapping of the extracellular region of the alpha(IIb) subunit is presented, using overlapping 20-peptides, in order to identify the binding sites of alpha(IIb) potentially involved in the platelet-aggregation event. Regions alpha(IIb) 313-332, alpha(IIb) 265-284 and alpha(IIb) 57-64 of alpha(IIb)beta(3) were identified as putative fibrinogen-binding domains because the corresponding peptides inhibited platelet aggregation and antagonized fibrinogen association, possibly by interacting with this ligand. The latter is further supported by the finding that the above peptides did not interfere with the binding of PAC-1 to the activated form of alpha(IIb)beta(3). Further more, alpha(IIb) 313-332 was found to bind to fibrinogen in a solid-phase binding assay. It should be emphasized that all the experiments in this study were carried out on activated platelets and consequently on the activated form of this integrin receptor. We hypothesize that RAD and RAE adhesive motifs, encompassed in alpha(IIb) 313-332, 265-284 and 57-64, are capable of recognizing complementary domains of fibrinogen, thus inhibiting the binding of this ligand to platelets. European Journal of Biochemistry
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- 2003
20. IL-1 beta transduces different signals than IL-1 alpha leading to class II antigen expression on beta-insulinoma RIN-5AH cells through specific receptors
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Vassiliadis, S., Soteriadou, K. P., and Papadopoulos, G. K.
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Kinetics ,Receptors, Interleukin-1/metabolism ,Dose-Response Relationship, Drug ,Insulinoma/*metabolism ,Interleukin-1/*metabolism ,Nitric Oxide/biosynthesis ,Tumor Cells, Cultured ,Animals ,Histocompatibility Antigens Class II/*metabolism ,Pancreatic Neoplasms/*metabolism ,Flow Cytometry ,Signal Transduction ,Rats - Abstract
Like most cytokines, IL-1 transduces its signals for growth, differentiation and diverse cellular functions after binding to specific receptors on the cell surface. Up to now two IL-1 receptors have been reported, type I which induces signal transduction and type II which binds IL-1 but does not transduce signalling. By using the rat insulinoma RIN-5AH cell line that expresses both types of receptor mRNA, and computer-assisted binding analysis, we show that interleukin-1 beta (IL-1 beta) binds to a single class of high affinity receptors with a Kd of 155 pmol/l. The average number of receptors on adherent cell layer is calculated to be 7300 per cell. 125I-IL-1 beta binding can be competed out by unlabelled IL-1 beta. 125I-IL-1 alpha binding can be also obtained and is subject to competition by cold IL-1 alpha. Its saturation curve, however, varies within experiments due to differential receptor up-regulation. These results have also been confirmed by FACS analysis using specific antibodies to type I and II IL-1 receptors, where type I receptor antibody binds strongly to RIN-5AH cells, and type II receptor antibody shows weak staining, also due to inadequate receptor up-regulation. In order to determine whether functional signal transduction occurs via the receptors detected, it is shown that IL-1 beta is able to induce MHC class II antigen expression on the surface of the RIN cells, whereas IL-1 alpha is unable to do so, indicating different signal reception by the cells. IL-1 beta-induced class II upregulation shows moderate signs of p21ras or/and PKC dependency, whereas IL-1 alpha strongly activates both pathways that probably regulate different functions. Finally, both IL-1 alpha and beta induce nitric oxide (NO) production in a time-dependent fashion which appears to be unrelated to the signals and pathways described, but may be involved in the onset of autoimmune type 1 diabetes. J Recept Signal Transduct Res
- Published
- 1997
21. Use of sequential oligopeptide carriers (SOCn) in the design of potent Leishmania gp63 immunogenic peptides
- Author
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Tsikaris, V., Sakarellos, C., SakarellosDaitsiotis, M., Cung, M. T., Marraud, M., Konidou, G., Tzinia, A., and Soteriadou, K. P.
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antigen ,fibronectin ,vaccine ,antibodies ,surface - Abstract
The antigenic sequence (250-257) Ac-IASRYDQL (gp63-SRYD) of the major surface glycoprotein of leishmania, gp63, was covalently attached to the Lys-(NH2)-H-E groups of a new sequential oligopeptide carrier (SOCn), namely; (Lys-Aib-Gly)(n) (n=5,6), in order to obtain potent immunogens and sire-specific antibodies. It was shown, using H-1-NMR spectroscopy; that the gp63-SRYD, octapeptides bound to the SOCn retain their original structural profile outlined by an ionic interaction between R and D side chains and a type I beta-turn involving the QNH --> RCO hydrogen bonding Also, the gp63-SRYD octapeptides linked to the carrier do not experience conformational restrictions, probably because of the favorable conformation of the SOCn. Immunizations of outbred rabbits with the peptide carriers designed resulted in high-titered antibody response to the gp63-SRYD octa-peptide and the gp63 cognate protein. Thus, this chemically defined model may be used for incorporating ''protective'' Leishmania epitopes and ultimately for the design of a multivalent synthetic vaccine against leishmaniosis. Peptide Research
- Published
- 1996
22. Olive tree extracts with potential leishmanicidal activity
- Author
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Kyriazis, ID, primary, Karagouni, E, additional, Soteriadou, K, additional, Skaltsounis, AL, additional, and Dotsika, E, additional
- Published
- 2008
- Full Text
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23. The Ser-Arg-Tyr-Asp Region of the Major Surface Glycoprotein of Leishmania Mimics the Arg-Gly-Asp-Ser Cell Attachment Region of Fibronectin
- Author
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Soteriadou, K. P., Remoundos, M. S., Katsikas, M. C., Tzinia, A. K., Tsikaris, V., Sakarellos, C., and Tzartos, S. J.
- Subjects
antigen ,receptor ,amino-acid ,identification ,monoclonal-antibody ,peptide-synthesis ,promastigotes ,protein ,membrane ,macrophages - Abstract
The major surface glycoprotein of Leishmania, gp63, a fibronectin-like molecule, plays a key role in parasite-macrophage interaction. Binding of gp63 to macrophage receptors is inhibited by Arg-Gly-Asp-Ser (RGDS)-containing synthetic peptides of fibronectin and by antibodies to these peptides. However, gp63 lacks an RGDS tetrapeptide. We sought to identify the region of gp63 that antigenically and functionally mimics the RGDS-containing region of fibronectin. We thus synthesized on polyethylene rods overlapping tetracosapeptides covering the whole sequence of Leishmania major gp63. gp63 affinity-purified antibodies raised against fibronectin and against the RGDS-containing fibronectin decapeptide RGDSPASSKP bound specifically to gp63 residues 241-264. Subsequently, by the use of smaller peptides, the gp63 tetrapeptide 252-255 (SRYD) was identified as the minimum antibody binding segment. Single residue substitution peptide analogues showed that indeed Tyr and Gly can be alternatively substituted in the SRYD- and RGDS-containing peptides of gp63 and fibronectin, respectively, without major effects on their antibody binding capacity. Subsequently, we investigated the effect of an SRYD peptide on promastigote-macrophage interaction in vitro; treatment of macrophages with an SRYD-containing gp63 octapeptide efficiently inhibited parasite attachment to macrophage receptors. Thus, the conserved among species sequence SRYD of gp63, with significant hydrophilicity, flexibility, and beta-turn propensity features, mimics antigenically and functionally the RGDS sequence of fibronectin. We suggest that this segment constitutes the putative gp63 adhesion site. Journal of Biological Chemistry
- Published
- 1992
24. First detection and genetic typing of Leishmania infantum MON-24 in a dog from the Moroccan Mediterranean coast: Genetic diversity of MON-24
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Haralambous, C., primary, Dakkak, A., additional, Pratlong, F., additional, Dedet, J.-P., additional, and Soteriadou, K., additional
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- 2007
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25. Natural and synthetic indirubins as potent and selective inhibitors of the protozoan parasite Leishmania donovani
- Author
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Xingi, E, primary, Smirlis, D, additional, Bisti, S, additional, Myrianthopoulos, V, additional, Magiatis, P, additional, Meijer, L, additional, Mikros, E, additional, Skaltsounis, AL, additional, and Soteriadou, K, additional
- Published
- 2007
- Full Text
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26. Identification and molecular characterization of a putative histone H1-like transcription factor in leishmania
- Author
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Tzortzakis, N, primary, Papageorgiou, F, additional, Tzinia, A, additional, and Soteriadou, K, additional
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- 1998
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27. Il-1β Transduces Different Signals than IL-1α Leading to Class II Antigen Expression on β-Insulinoma Rin-5AH Cells through Specific Receptors
- Author
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Vassiliadis, S., primary, Soteriadou, K. P., additional, and Papadopoulos, G. K., additional
- Published
- 1997
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28. Evidence of transferrin binding sites on the surface of Leishmania promastigotes.
- Author
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Voyiatzaki, C S, primary and Soteriadou, K P, additional
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- 1990
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29. Effect of iron chelation on the in-vitro growth of Leishmania promastigotes.
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Soteriadou, Ketty, Papavassiliou, Pericles, Voyiatzaki, Chryssa, Boelaert, Johan, Soteriadou, K, Papavassiliou, P, Voyiatzaki, C, and Boelaert, J
- Abstract
The development of vaccines and drugs to control leishmaniasis is urgently needed. The presence of a leishmania transferrin receptor on the parasite suggests that an adequate supply of iron is needed for the life cycle of leishmania. We have investigated the effect of iron deprivation on the growth of leishmania promastigotes in vitro using an iron chelation approach. All chelators tested reduced the rate of promastigote multiplication in a dose-dependent fashion, whereas referrated ones did not. The hydroxypyridin-4-one chelators CP94 and L1 were found to be more efficient than desferrioxamine. We suggest that iron depletion may be an effective mechanism against leishmania infection. [ABSTRACT FROM AUTHOR]
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- 1995
30. Identification of monomeric and oligomeric forms of a major Leishmania infantum antigen by using monoclonal antibodies
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Soteriadou, K P, Tzinia, A K, Hadziantoniou, M G, and Tzartos, S J
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Ten monoclonal antibodies (MAbs) produced against isolated Leishmania infantum membranes were used as probes of L. infantum membrane antigens. Western blots of L. infantum membranes, sodium dodecyl sulfate solubilized and heated at 100 degrees C before analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showed that all 10 MAbs recognized a band at 58 kilodaltons (kDa). However, when solubilized membranes were not heated, 2 of the 10 MAbs recognized, in addition to the 58-kDa band, bands of higher molecular weight. Limited digestion of heated or nonheated membranes showed that both groups of MAbs (i.e., not capable or capable of binding to the high-molecular-weight bands) recognized the same proteolytic digests. Hydrophilic forms of the above proteins, possessing proteolytic activity, were detected and isolated by gel filtration. Protein staining of the isolated monomer analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under reducing and heating conditions, revealed incomplete reduction of the 58-kDa protein. The reduced form of the 58-kDa protein migrated at 63 to 65 kDa and was not recognized by the MAbs. These results suggest the existence of a monomeric and an oligomeric form of the 58-kDa antigen. The observed inhibition of Leishmania promastigote-macrophage binding caused by MAbs representative of the two groups (capable of oligomeric and/or monomeric antigen recognition) suggest that the 58-kDa monomer and oligomer play an important role in promastigote-macrophage interaction. We suggest that the 58-kDa L. infantum antigen is the major surface Leishmania antigen (p63) identified by others.
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- 1988
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31. Regulation of 2–5 A synthetase activity and antiviral state in interferon treated chick cells
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Lab, M., primary, Thang, M.N., additional, Soteriadou, K., additional, Koehren, F., additional, and Justesen, J., additional
- Published
- 1982
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32. Leishmania donovani leishmaniasis in Cyprus.
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Antoniou M, Haralambous C, Mazeris A, Pratlong F, Dedet JP, and Soteriadou K
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- 2008
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33. Indirubin Analogues Inhibit Trypanosoma brucei Glycogen Synthase Kinase 3 Short and T. brucei Growth.
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Efstathiou A, Gaboriaud-Kolar N, Myrianthopoulos V, Vougogiannopoulou K, Subota I, Aicher S, Mikros E, Bastin P, Skaltsounis AL, Soteriadou K, and Smirlis D
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- Animals, Cell Line, Indoles pharmacology, Insecta parasitology, Structure-Activity Relationship, Trypanosomiasis, African drug therapy, Glycogen Synthase Kinase 3 antagonists & inhibitors, Protein Kinase Inhibitors pharmacology, Trypanocidal Agents pharmacology, Trypanosoma brucei brucei drug effects, Trypanosoma brucei brucei metabolism
- Abstract
The protozoan parasite Trypanosoma brucei is the causative agent of human African trypanosomiasis (HAT). The disease is fatal if it remains untreated, whereas most drug treatments are inadequate due to high toxicity, difficulties in administration, and low central nervous system penetration. T. brucei glycogen synthase kinase 3 short ( Tb GSK3s) is essential for parasite survival and thus represents a potential drug target that could be exploited for HAT treatment. Indirubins, effective leishmanicidals, provide a versatile scaffold for the development of potent GSK3 inhibitors. Herein, we report on the screening of 69 indirubin analogues against T. brucei bloodstream forms. Of these, 32 compounds had potent antitrypanosomal activity (half-maximal effective concentration = 0.050 to 3.2 μM) and good selectivity for the analogues over human HepG2 cells (range, 7.4- to over 641-fold). The majority of analogues were potent inhibitors of Tb GSK3s, and correlation studies for an indirubin subset, namely, the 6-bromosubstituted 3'-oxime bearing an extra bulky substituent on the 3' oxime [(6-BIO-3'-bulky)-substituted indirubins], revealed a positive correlation between kinase inhibition and antitrypanosomal activity. Insights into this indirubin- Tb GSK3s interaction were provided by structure-activity relationship studies. Comparison between 6-BIO-3'-bulky-substituted indirubin-treated parasites and parasites silenced for Tb GSK3s by RNA interference suggested that the above-described compounds may target Tb GSK3s in vivo To further understand the molecular basis of the growth arrest brought about by the inhibition or ablation of Tb GSK3s, we investigated the intracellular localization of Tb GSK3s. Tb GSK3s was present in cytoskeletal structures, including the flagellum and basal body area. Overall, these results give insights into the mode of action of 6-BIO-3'-bulky-substituted indirubins that are promising hits for antitrypanosomal drug discovery., (Copyright © 2019 American Society for Microbiology.)
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- 2019
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34. An inhibitor-driven study for enhancing the selectivity of indirubin derivatives towards leishmanial Glycogen Synthase Kinase-3 over leishmanial cdc2-related protein kinase 3.
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Efstathiou A, Gaboriaud-Kolar N, Smirlis D, Myrianthopoulos V, Vougogiannopoulou K, Alexandratos A, Kritsanida M, Mikros E, Soteriadou K, and Skaltsounis AL
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- Animals, Binding Sites, CDC2-CDC28 Kinases genetics, CDC2-CDC28 Kinases metabolism, Gene Expression Regulation, Enzymologic, Glycogen Synthase Kinase 3 genetics, Glycogen Synthase Kinase 3 metabolism, Indoles chemistry, Indoles pharmacology, Leishmania drug effects, Membrane Proteins, Models, Molecular, Molecular Sequence Data, Molecular Structure, Protein Conformation, Saccharomyces cerevisiae Proteins, Small Molecule Libraries, Species Specificity, CDC2-CDC28 Kinases antagonists & inhibitors, Glycogen Synthase Kinase 3 antagonists & inhibitors, Leishmania enzymology
- Abstract
Background: In search of new antiparasitic agents for overcoming the limitations of current leishmaniasis chemotherapy, we have previously shown that 6-bromoindirubin-3'-oxime (6BIO) and several other 6-substituted analogues of indirubin, a naturally occurring bis-indole present in mollusks and plants, displayed reverse selectivity from the respective mammalian kinases, targeting more potently the leishmanial Cyclin-Dependent Kinase-1 (CDK1) homologue [cdc2-related protein kinase 3 (LCRK3)] over leishmanial Glycogen Synthase Kinase-3 (LGSK-3). This reversal of selectivity in Leishmania parasites compared to mammalian cells makes the design of specific indirubin-based LGSK-3 inhibitors difficult. In this context, the identification of compounds bearing specific substitutions that shift indirubin inhibition towards LGSK-3, previously found to be a potential drug target, over LCRK3 is imperative for antileishmanial targeted drug discovery., Methods: A new in-house indirubin library, composed of 35 compounds, initially designed to target mammalian kinases (CDKs, GSK-3), was tested against Leishmania donovani promastigotes and intracellular amastigotes using the Alamar blue assay. Indirubins with antileishmanial activity were tested against LGSK-3 and LCRK3 kinases, purified from homologous expression systems. Flow cytometry (FACS) was used to measure the DNA content for cell-cycle analysis and the mode of cell death. Comparative structural analysis of the involved kinases was then performed using the Szmap algorithm., Results: We have identified 7 new indirubin analogues that are selective inhibitors of LGSK-3 over LCRK3. These new inhibitors were also found to display potent antileishmanial activity with GI50 values of <1.5 μΜ. Surprisingly, all the compounds that displayed enhanced selectivity towards LGSK-3, were 6BIO analogues bearing an additional 3'-bulky amino substitution, namely a piperazine or pyrrolidine ring. A comparative structural analysis of the two aforementioned leishmanial kinases was subsequently undertaken to explain and rationalize the selectivity trend determined by the in vitro binding assays. Interestingly, the latter analysis showed that selectivity could be correlated with differences in kinase solvation thermo dynamics induced by minor sequence variations of the otherwise highly similar ATP binding pockets., Conclusions: In conclusion, 3'-bulky amino substituted 6-BIO derivatives, which demonstrate enhanced specificity towards LGSK-3, represent a new scaffold for targeted drug development to treat leishmaniasis.
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- 2014
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35. Genetic diversity and structure in Leishmania infantum populations from southeastern Europe revealed by microsatellite analysis.
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Gouzelou E, Haralambous C, Antoniou M, Christodoulou V, Martinković F, Živičnjak T, Smirlis D, Pratlong F, Dedet JP, Özbel Y, Toz SÖ, Presber W, Schönian G, and Soteriadou K
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- Animals, Dogs, Europe, Humans, Microsatellite Repeats, Phylogeny, Turkey, Genetic Variation, Leishmania infantum genetics
- Abstract
Background: The dynamic re-emergence of visceral leishmaniasis (VL) in south Europe and the northward shift to Leishmania-free European countries are well-documented. However, the epidemiology of VL due to Leishmania infantum in southeastern (SE) Europe and the Balkans is inadequately examined. Herein, we aim to re-evaluate and compare the population structure of L. infantum in SE and southwestern (SW) Europe., Methods: Leishmania strains collected from humans and canines in Turkey, Cyprus, Bulgaria, Greece, Albania and Croatia, were characterized by the K26-PCR assay and multilocus enzyme electrophoresis (MLEE). Genetic diversity was assessed by multilocus microsatellite typing (MLMT) and MLM Types were analyzed by model- and distance- based algorithms to infer the population structure of 128 L. infantum strains., Results: L. infantum MON-1 was found predominant in SE Europe, whilst 16.8% of strains were MON-98. Distinct genetic populations revealed clear differentiation between SE and SW European strains. Interestingly, Cypriot canine isolates were genetically isolated and formed a monophyletic group, suggesting the constitution of a clonal MON-1 population circulating among dogs. In contrast, two highly heterogeneous populations enclosed all MON-1 and MON-98 strains from the other SE European countries. Structure sub-clustering, phylogenetic and Splitstree analysis also revealed two distinct Croatian subpopulations. A mosaic of evolutionary effects resulted in consecutive sub-structuring, which indicated substantial differentiation and gene flow among strains of both zymodemes., Conclusions: This is the first population genetic study of L. infantum in SE Europe and the Balkans. Our findings demonstrate the differentiation between SE and SW European strains; revealing the partition of Croatian strains between these populations and the genetic isolation of Cypriot strains. This mirrors the geographic position of Croatia located in central Europe and the natural isolation of the island of Cyprus. We have analysed the largest number of MON-98 strains so far. Our results indicate extensive gene flow, recombination and no differentiation between MON-1 and MON-98 zymodemes. No correlation either to host specificity or place and year of strain isolation was identified. Our findings may be associated with intensive host migration and common eco-epidemiological characteristics in these countries and give valuable insight into the dynamics of VL.
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- 2013
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36. The loss of virulence of histone H1 overexpressing Leishmania donovani parasites is directly associated with a reduction of HSP83 rate of translation.
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Alexandratos A, Clos J, Samiotaki M, Efstathiou A, Panayotou G, Soteriadou K, and Smirlis D
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- Animals, Cell Line, Electrophoresis, Gel, Two-Dimensional, Endocytosis, Histones genetics, Hot Temperature, Leishmania donovani genetics, Leishmania donovani growth & development, Leishmania donovani radiation effects, Macrophages parasitology, Mice, Proteome analysis, Protozoan Proteins analysis, Stress, Physiological, Temperature, Gene Expression Regulation, Heat-Shock Proteins biosynthesis, Histones metabolism, Leishmania donovani pathogenicity, Protein Biosynthesis, Protozoan Proteins biosynthesis, Virulence Factors biosynthesis
- Abstract
Overexpression of Leishmania histone H1 (LeishH1) was previously found to cause a promastigote-to-amastigote differentiation handicap, deregulation of cell-cycle progression, and loss of parasite infectivity. The aim of this study was to identify changes in the proteome of LeishH1 overexpressing parasites associated with the avirulent phenotype observed. 2D-gel electrophoresis analysis revealed only a small protein subset of differentially expressed proteins in the LeishH1 overexpressing promastigotes. Among these was the chaperone HSP83, known for its protective role in Leishmania drug-induced apoptosis, which displayed lower translational rates. To investigate if the lower expression levels of HSP83 are associated with the differentiation handicap, we assayed the thermostability of parasites by subjecting them to heat-shock (25°C→37°C), a natural stress-factor occurring during stage differentiation. Heat-shock promoted apoptosis to a greater extent in the LeishH1 overexpressing parasites. Interestingly, these parasites were not only more sensitive to heat-shock but also to drug-induced [Sb(III)] cell-death. In addition, the restoration of HSP83 levels re-established drug resistance, and restored infectivity to LeishH1 overexpressing parasites in the murine J774 macrophage model. Overall, this study suggests that LeishH1 levels are critical for the parasite's stress-induced adaptation within the mammalian host, and highlights the cross-talk between pathways involved in drug resistance, apoptosis and virulence., (© 2013 John Wiley & Sons Ltd.)
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- 2013
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37. Multilocus microsatellite typing (MLMT) of strains from Turkey and Cyprus reveals a novel monophyletic L. donovani sensu lato group.
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Gouzelou E, Haralambous C, Amro A, Mentis A, Pratlong F, Dedet JP, Votypka J, Volf P, Toz SO, Kuhls K, Schönian G, and Soteriadou K
- Subjects
- Animals, Cluster Analysis, Cyprus epidemiology, Genotype, Humans, Leishmania donovani isolation & purification, Molecular Epidemiology, Phylogeography, Turkey epidemiology, Leishmania donovani classification, Leishmania donovani genetics, Leishmaniasis, Visceral epidemiology, Leishmaniasis, Visceral parasitology, Microsatellite Repeats, Molecular Typing
- Abstract
Background: New foci of human CL caused by strains of the Leishmania donovani (L. donovani) complex have been recently described in Cyprus and the Çukurova region in Turkey (L. infantum) situated 150 km north of Cyprus. Cypriot strains were typed by Multilocus Enzyme Electrophoresis (MLEE) using the Montpellier (MON) system as L. donovani zymodeme MON-37. However, multilocus microsatellite typing (MLMT) has shown that this zymodeme is paraphyletic; composed of distantly related genetic subgroups of different geographical origin. Consequently the origin of the Cypriot strains remained enigmatic., Methodology/principal Findings: The Cypriot strains were compared with a set of Turkish isolates obtained from a CL patient and sand fly vectors in south-east Turkey (Çukurova region; CUK strains) and from a VL patient in the south-west (Kuşadasi; EP59 strain). These Turkish strains were initially analyzed using the K26-PCR assay that discriminates MON-1 strains by their amplicon size. In line with previous DNA-based data, the strains were inferred to the L. donovani complex and characterized as non MON-1. For these strains MLEE typing revealed two novel zymodemes; L. donovani MON-309 (CUK strains) and MON-308 (EP59). A population genetic analysis of the Turkish isolates was performed using 14 hyper-variable microsatellite loci. The genotypic profiles of 68 previously analyzed L. donovani complex strains from major endemic regions were included for comparison. Population structures were inferred by combination of bayesian model-based and distance-based approaches. MLMT placed the Turkish and Cypriot strains in a subclade of a newly discovered, genetically distinct L. infantum monophyletic group, suggesting that the Cypriot strains may originate from Turkey., Conclusion: The discovery of a genetically distinct L. infantum monophyletic group in the south-eastern Mediterranean stresses the importance of species genetic characterization towards better understanding, monitoring and controlling the spread of leishmaniasis in this region.
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- 2012
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38. Trypanosomatid apoptosis: 'Apoptosis' without the canonical regulators.
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Smirlis D and Soteriadou K
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- Leishmania genetics, Leishmania metabolism, Trypanosoma genetics, Trypanosoma metabolism, Apoptosis, Leishmania physiology, Trypanosoma physiology
- Abstract
Apoptosis is a regulated process of cell death originally described in multicelullar organisms contributing to their development and functionality. There is now increasing experimental evidence that a similar form of cell death is operative in unicellular eukaryotes, including trypanosomatids of the genera Trypanosoma and Leishmania. The determination of ancestral executors and regulators of 'apoptosis' in these protozoa belonging to the most primitive eukaryotes that appeared on earth 1.5 billion years ago, provide an exciting challenge in the understanding of the evolution of apoptosis-regulating processes. A review of the present knowledge of trypanosomatid apoptosis points to the fact that these dying protozoa acquire common apoptotic morphological features as metazoan cells, although they lack many of the molecules accepted today as canonical apoptosis mediators (Bcl-2 family members, caspases, TNF related family of receptors). Herein, we discuss how the knowledge of regulators and executors of trypanosomatid apoptosis may provide answers to the gaps concerning the origin of apoptosis. The aim of this addendum is to emphasize the need for classifying the ancestral death program and to discuss how this relates to the complex death programs in multicellular lineages, with the hope to stimulate further enquiry and research into this area.
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- 2011
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39. Targeting essential pathways in trypanosomatids gives insights into protozoan mechanisms of cell death.
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Smirlis D, Duszenko M, Ruiz AJ, Scoulica E, Bastien P, Fasel N, and Soteriadou K
- Abstract
Apoptosis is a normal component of the development and health of multicellular organisms. However, apoptosis is now considered a prerogative of unicellular organisms, including the trypanosomatids of the genera Trypanosoma spp. and Leishmania spp., causative agents of some of the most important neglected human diseases. Trypanosomatids show typical hallmarks of apoptosis, although they lack some of the key molecules contributing to this process in metazoans, like caspase genes, Bcl-2 family genes and the TNF-related family of receptors. Despite the lack of these molecules, trypanosomatids appear to have the basic machinery to commit suicide. The components of the apoptotic execution machinery of these parasites are slowly coming into light, by targeting essential processes and pathways with different apoptogenic agents and inhibitors. This review will be confined to the events known to drive trypanosomatid parasites to apoptosis.
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- 2010
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40. Leishmaniases and the Cyprus paradox.
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Mazeris A, Soteriadou K, Dedet JP, Haralambous C, Tsatsaris A, Moschandreas J, Messaritakis I, Christodoulou V, Papadopoulos B, Ivovic V, Pratlong F, Loucaides F, and Antoniou M
- Subjects
- Animals, Cyprus epidemiology, Dog Diseases epidemiology, Dogs, Enzyme-Linked Immunosorbent Assay veterinary, Female, Humans, Leishmaniasis blood, Leishmaniasis epidemiology, Male, Phlebotomus, Polymerase Chain Reaction veterinary, Seroepidemiologic Studies, Species Specificity, Leishmaniasis veterinary
- Abstract
In Cyprus, leishmaniasis has been considered exclusively a veterinary problem. It was prevalent before 1945, and until its recent reemergence, it was nearly eradicated by 1996 as a consequence of the destruction of reservoir hosts and vectors. A survey carried out to provide an unbiased estimate of current transmission rates in dogs and humans showed a 9-fold increase in dog seroprevalence (reaching 14.9%) compared with 10 years ago. However, no human cases caused by Leishmania infantum were detected, although L. donovani cases were reported recently. The 62 strains isolated from dogs were typed as L. infantum MON-1 (98.4%), which is the predominating zymodeme in the Mediterranean region, and MON-98 (1.6%). The Phlebotomus species P. tobbi (vector of L. infantum in Cyprus), P. galilaeus, and P. papatasi were the predominant species captured. Two transmission cycles seem to run in parallel in Cyprus: in dogs with L. infantum and in humans with L. donovani.
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- 2010
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41. Leishmania donovani Ran-GTPase interacts at the nuclear rim with linker histone H1.
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Smirlis D, Boleti H, Gaitanou M, Soto M, and Soteriadou K
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- Cell Cycle, Flow Cytometry, Immunoblotting, Leishmania donovani genetics, Microscopy, Confocal, Protein Binding, Protozoan Proteins genetics, Transfection, ran GTP-Binding Protein genetics, Cell Nucleus metabolism, Histones metabolism, Leishmania donovani metabolism, Protozoan Proteins metabolism, ran GTP-Binding Protein metabolism
- Abstract
Ran-GTPase regulates multiple cellular processes such as nucleocytoplasmic transport, mitotic spindle assembly, nuclear envelope assembly, cell-cycle progression and the mitotic checkpoint. The leishmanial Ran protein, in contrast with its mammalian counterpart which is predominately nucleoplasmic, is localized at the nuclear rim. The aim of the present study was to characterize the LdRan (Leishmania donovani Ran) orthologue with an emphasis on the Ran-histone association. LdRan was found to be developmentally regulated, expressed 3-fold less in the amastigote stage. LdRan overexpression caused a growth defect linked to a delayed S-phase progression in promastigotes as for its mammalian counterpart. We report for the first time that Ran interacts with a linker histone, histone H1, in vitro and that the two proteins co-localize at the parasite nuclear rim. Interaction of Ran with core histones H3 and H4, creating in metazoans a chromosomal Ran-GTP gradient important for mitotic spindle assembly, is speculative in Leishmania spp., not only because this parasite undergoes a closed mitosis, but also because the main localization of LdRan is different from that of core histone H3. Interaction of Ran with the leishmanial linker histone H1 (LeishH1) suggests that this association maybe involved in modulation of pathways other than those documented for the metazoan Ran-core histone association.
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- 2009
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42. 6-Br-5methylindirubin-3'oxime (5-Me-6-BIO) targeting the leishmanial glycogen synthase kinase-3 (GSK-3) short form affects cell-cycle progression and induces apoptosis-like death: exploitation of GSK-3 for treating leishmaniasis.
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Xingi E, Smirlis D, Myrianthopoulos V, Magiatis P, Grant KM, Meijer L, Mikros E, Skaltsounis AL, and Soteriadou K
- Subjects
- Animals, Cell Cycle drug effects, Cells, Cultured, Cyclin-Dependent Kinases chemistry, Cyclin-Dependent Kinases metabolism, Drug Evaluation, Preclinical, Flow Cytometry, Fluorescent Dyes, Glycogen Synthase Kinase 3 chemistry, Glycogen Synthase Kinase 3 metabolism, Humans, Immunoblotting, Leishmaniasis metabolism, Apoptosis, Cyclin-Dependent Kinases antagonists & inhibitors, Glycogen Synthase Kinase 3 antagonists & inhibitors, Indoles pharmacology, Leishmania donovani metabolism, Leishmaniasis drug therapy, Oximes pharmacology
- Abstract
Indirubins known to target mammalian cyclin-dependent kinases (CDKs) and glycogen synthase kinase (GSK-3) were tested for their antileishmanial activity. 6-Br-indirubin-3'-oxime (6-BIO), 6-Br-indirubin-3'acetoxime and 6-Br-5methylindirubin-3'oxime (5-Me-6-BIO) were the most potent inhibitors of Leishmania donovani promastigote and amastigote growth (half maximal inhibitory concentration (IC(50)) values < or =1.2 microM). Since the 6-Br substitution on the indirubin backbone greatly enhances the selectivity for mammalian GSK-3 over CDKs, we identified the leishmanial GSK-3 homologues, a short (LdGSK-3s) and a long one, focusing on LdGSK-3s which is closer to human GSK-3beta, for further studies. Kinase assays showed that 5-Me-6-BIO inhibited LdGSK-3s more potently than CRK3 (the CDK1 homologue in Leishmania), whilst 6-BIO was more selective for CRK3. Promastigotes treated with 5-Me-6-BIO accumulated in the S and G2/M cell-cycle phases and underwent apoptosis-like death. Interestingly, these phenotypes were completely reversed in parasites over-expressing LdGSK-3s. This finding strongly supports that LdGSK-3s is: (i) the intracellular target of 5-Me-6-BIO, and (ii) involved in cell-cycle control and in pathways leading to apoptosis-like death. 6-BIO treatment induced a G2/M arrest, consistent with inhibition of CRK3 and apoptosis-like death. These effects were partially reversed in parasites over-expressing LdGSK-3s suggesting that in vivo 6-BIO may also target LdGSK-3s. Molecular docking of 5-Me-6-BIO in CRK3 and 6-BIO in human GSK-3beta and LdGSK-3s active sites predict the existence of functional/structural differences that are sufficient to explain the observed difference in their affinity. In conclusion, LdGSK-3s is validated as a potential drug target in Leishmania and could be exploited for the development of selective indirubin-based leishmanicidals.
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- 2009
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43. Key role of the 3' untranslated region in the cell cycle regulated expression of the Leishmania infantum histone H2A genes: minor synergistic effect of the 5' untranslated region.
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Abanades DR, Ramírez L, Iborra S, Soteriadou K, González VM, Bonay P, Alonso C, and Soto M
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- 3' Untranslated Regions, 5' Untranslated Regions, Animals, Histones metabolism, Leishmania infantum genetics, Leishmania infantum metabolism, Protozoan Proteins metabolism, Cell Cycle, Gene Expression, Histones genetics, Leishmania infantum cytology, Protozoan Proteins genetics, Untranslated Regions
- Abstract
Background: Histone synthesis in Leishmania is tightly coupled to DNA replication by a post-transcriptional mechanism operating at the level of translation., Results: In this work we have analyzed the implication of the 5' and 3' untranslated regions (UTR) in the cell cycle regulated expression of the histone H2A in Leishmania infantum. For that purpose, L. infantum promastigotes were stably transfected with different plasmid constructs in which the CAT coding region used as a reporter was flanked by the 5' and 3' UTR regions of the different H2A genes. We report that in spite of their sequence differences, histone H2A 5' and 3' UTRs conferred a cell cycle dependent pattern of expression on the CAT reporter since de novo synthesis of CAT increased when parasites enter the S phase. Using one established L. infantum cell line we showed that CAT expression is controlled by the same regulatory events that control the endogenous histone gene expression. Thus, although we did not detect changes in the level of CAT mRNAs during cell cycle progression, a drastic change in the polysome profiles of CAT mRNAs was observed during the progression from G1 to S phase. In the S phase CAT mRNAs were on polyribosomal fractions, but in the G1 phase the association of CAT transcripts with ribosomes was impaired. Furthermore, it was determined that the addition of just the H2A 3' UTR to the CAT reporter gene is sufficient to achieve a similar pattern of post-transcriptional regulation indicating that this region contains the major regulatory sequences involved in the cell cycle dependent expression of the H2A genes. On the other hand, although CAT transcripts bearing the H2A 5' alone were translated both in the G1 and S phase, higher percentages of transcripts were detected on polyribosomes in the S phase correlating with an increase in the de novo synthesis of CAT. Thus, it can be concluded that this region also contributes, although to a minor extent than the 3' UTR, in the enhancement of translation in the S phase relative to the G1 phase., Conclusion: Our findings indicate that both, the 5' and the 3' UTRs contain sequence elements that contribute to the cell cycle expression of L. infantum H2A. The 3' UTR region is essential for cell cycle dependent translation of the L. infantum H2A transcripts whereas the 5' UTR has a minor contribution in their S phase dependent translation.
- Published
- 2009
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44. The paraphyletic composition of Leishmania donovani zymodeme MON-37 revealed by multilocus microsatellite typing.
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Alam MZ, Haralambous C, Kuhls K, Gouzelou E, Sgouras D, Soteriadou K, Schnur L, Pratlong F, and Schönian G
- Subjects
- Africa, Eastern, Animals, China, Cluster Analysis, Cyprus, Genotype, Geography, Humans, India, Israel, Leishmania donovani genetics, Middle East, Molecular Epidemiology, Phylogeny, DNA Fingerprinting methods, DNA, Protozoan genetics, Leishmania donovani classification, Leishmania donovani isolation & purification, Leishmaniasis, Visceral parasitology, Microsatellite Repeats
- Abstract
Multilocus microsatellite typing (MLMT) was employed to compare strains of Leishmania donovani belonging to the MON-37 zymodeme (MON-37 strains) from Cyprus and Israel to MON-37 strains from the Indian subcontinent, the Middle East, China and East Africa as well as strains of other zymodemes. The MLMT data were processed with a distance-based method for construction of phylogenetic trees, factorial correspondence analysis and a Bayesian model-based clustering algorithm. All three approaches assigned the MON-37 strains to different distantly related genetically defined subgroups, corresponding to their geographical origin. Specifically, the Kenyan, Sri Lankan and Indian MON-37 strains were genetically closer to strains of other zymodemes from the same regions than to MON-37 strains from other areas. MON-37 strains from Cyprus and Israel were clearly different not only among themselves, but also compared to all the other MON-37 strains studied and could, therefore, be autochthonous. This study showed that the zymodeme MON-37 is paraphyletic and does not reflect the genetic relationship between strains of different geographical origin.
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- 2009
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45. Leishmania donovani leishmaniasis in Cyprus.
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Antoniou M, Haralambous C, Mazeris A, Pratlong F, Dedet JP, and Soteriadou K
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- Animals, Cyprus epidemiology, Humans, Leishmania donovani physiology, Leishmaniasis epidemiology, Psychodidae parasitology, Insect Vectors physiology, Leishmaniasis transmission, Psychodidae physiology
- Published
- 2009
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46. Drug regimens for visceral leishmaniasis in Mediterranean countries.
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Gradoni L, Soteriadou K, Louzir H, Dakkak A, Toz SO, Jaffe C, Dedet JP, Campino L, Cañavate C, and Dujardin JC
- Subjects
- Adolescent, Adult, Africa, Northern, Aged, Aged, 80 and over, Amphotericin B economics, Animals, Antimony Sodium Gluconate economics, Antiprotozoal Agents economics, Child, Child, Preschool, Clinical Protocols, Europe, Female, Humans, Israel, Leishmaniasis, Visceral economics, Leishmaniasis, Visceral immunology, Male, Meglumine economics, Middle Aged, Middle East, Amphotericin B therapeutic use, Antimony Sodium Gluconate therapeutic use, Antiprotozoal Agents therapeutic use, Immunocompromised Host drug effects, Leishmaniasis, Visceral drug therapy, Meglumine therapeutic use
- Abstract
Until the early 1990s, pentavalent antimony was the only documented first-line drug employed for the treatment of zoonotic visceral leishmaniasis (VL) in the Mediterranean, with reported cure rates exceeding 95% in immunocompetent patients. The emergence of antimony resistance in other endemic settings and the increase in drug options have stimulated re-evaluation of the current therapeutic approaches and outcomes in Mediterranean countries. A scientific consortium ('LeishMed' network) collected updated information from collaborating clinical health centres of 11 endemic countries of Southern Europe, Northern Africa and the Middle East. In contrast with the previous situation, VL is now treated differently in the region, basically through three approaches: (1) In Northern Africa and in part of the Middle East, pentavalent antimony is still the mainstay for therapy, with no alternative drug options for treating relapses; (2) In some European countries and Israel, both pentavalent antimony and lipid-associated amphotericin B (AmB) formulations are used as first-line drugs, although in different patients' categories; (3) In other countries of Europe, mainly liposomal AmB is employed. Importantly, cure rates exhibited by different drugs, including antimonials in areas where they are still in routine use, are similarly high (>/=95%) in immunocompetent patients. Our findings show that antimony resistance is not an emerging problem in the Mediterranean. A country's wealth affects the treatment choice, which represents a balance between drug efficacy, toxicity and cost, and costs associated with patient's care.
- Published
- 2008
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47. Differentiation and gene flow among European populations of Leishmania infantum MON-1.
- Author
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Kuhls K, Chicharro C, Cañavate C, Cortes S, Campino L, Haralambous C, Soteriadou K, Pratlong F, Dedet JP, Mauricio I, Miles M, Schaar M, Ochsenreither S, Radtke OA, and Schönian G
- Subjects
- Animals, Dog Diseases epidemiology, Dogs, Europe epidemiology, Genetic Variation, Genotype, Host-Parasite Interactions, Humans, Leishmania infantum classification, Leishmaniasis, Visceral epidemiology, Microsatellite Repeats, Phylogeny, Dog Diseases parasitology, Gene Flow, Leishmania infantum genetics, Leishmania infantum isolation & purification, Leishmaniasis, Visceral parasitology, Leishmaniasis, Visceral veterinary
- Abstract
Background: Leishmania infantum is the causative agent of visceral and cutaneous leishmaniasis in the Mediterranean region, South America, and China. MON-1 L. infantum is the predominating zymodeme in all endemic regions, both in humans and dogs, the reservoir host. In order to answer important epidemiological questions it is essential to discriminate strains of MON-1., Methodology/principal Findings: We have used a set of 14 microsatellite markers to analyse 141 strains of L. infantum mainly from Spain, Portugal, and Greece of which 107 strains were typed by MLEE as MON-1. The highly variable microsatellites have the potential to discriminate MON-1 strains from other L. infantum zymodemes and even within MON-1 strains. Model- and distance-based analysis detected a considerable amount of structure within European L. infantum. Two major monophyletic groups-MON-1 and non-MON-1-could be distinguished, with non-MON-1 being more polymorphic. Strains of MON-98, 77, and 108 were always part of the MON-1 group. Among MON-1, three geographically determined and genetically differentiated populations could be identified: (1) Greece; (2) Spain islands-Majorca/Ibiza; (3) mainland Portugal/Spain. All four populations showed a predominantly clonal structure; however, there are indications of occasional recombination events and gene flow even between MON-1 and non-MON-1. Sand fly vectors seem to play an important role in sustaining genetic diversity. No correlation was observed between Leishmania genotypes, host specificity, and clinical manifestation. In the case of relapse/re-infection, only re-infections by a strain with a different MLMT profile can be unequivocally identified, since not all strains have individual MLMT profiles., Conclusion: In the present study for the first time several key epidemiological questions could be addressed for the MON-1 zymodeme, because of the high discriminatory power of microsatellite markers, thus creating a basis for further epidemiological investigations.
- Published
- 2008
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48. Spread of vector-borne diseases and neglect of Leishmaniasis, Europe.
- Author
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Dujardin JC, Campino L, Cañavate C, Dedet JP, Gradoni L, Soteriadou K, Mazeris A, Ozbel Y, and Boelaert M
- Subjects
- Animals, Communicable Diseases, Emerging epidemiology, Communicable Diseases, Emerging parasitology, Drug Resistance, Europe epidemiology, Greenhouse Effect, Humans, Leishmaniasis, Visceral drug therapy, Phlebotomus parasitology, Seroepidemiologic Studies, Endemic Diseases, Leishmaniasis, Visceral epidemiology
- Abstract
The risk for reintroduction of some exotic vector-borne diseases in Europe has become a hot topic, while the reality of others is neglected at the public health policy level. Leishmaniasis is endemic in all southern countries of Europe, with approximately 700 autochthonous human cases reported each year (3,950 if Turkey is included). Asymptomatic cases have been estimated at 30-100/1 symptomatic case, and leishmaniasis has up to 25% seroprevalence in domestic dogs. Even though leishmaniasis is essentially associated with Leishmania infantum and visceral leishmaniasis, new species, such as L. donovani and L. tropica, might colonize European sand fly vectors. Drug-resistant L. infantum strains might be exported outside Europe through dogs. Despite this possibility, no coordinated surveillance of the disease exists at the European level. In this review of leishmaniasis importance in Europe, we would like to bridge the gap between research and surveillance and control.
- Published
- 2008
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49. Development of a molecular assay specific for the Leishmania donovani complex that discriminates L. donovani/Leishmania infantum zymodemes: a useful tool for typing MON-1.
- Author
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Haralambous C, Antoniou M, Pratlong F, Dedet JP, and Soteriadou K
- Subjects
- Animals, DNA, Protozoan chemistry, DNA, Protozoan genetics, Dogs, Electrophoresis, Starch Gel, Enzymes analysis, Genotype, Humans, Molecular Epidemiology economics, Molecular Sequence Data, Sequence Analysis, DNA, Leishmania donovani classification, Leishmania donovani genetics, Leishmania infantum genetics, Molecular Epidemiology methods, Polymerase Chain Reaction methods, Polymorphism, Restriction Fragment Length, Protozoan Proteins genetics
- Abstract
We have developed a simple, rapid, sensitive, and cost-effective typing method, based on the amplicon size of the K26 gene, capable of species/strain discrimination of Leishmania donovani complex strains causing visceral leishmaniasis (VL). It was evaluated on 112 strains and compared with multilocus enzyme electrophoresis (MLEE) typing. The K26 polymerase chain reaction (PCR) applied on 26 representative L. donovani complex strains gave 14 different amplicon sizes. The assay was specific to the L. donovani complex and discriminated L. infantum from L. donovani strains. MON-1 strains were also easily distinguished from other non-MON-1. Surprisingly, 29.3% of the Greek strains included in this study were MLEE typed as MON-98 and gave exclusively a 940-bp amplicon. The majority of Greek MON-1 strains gave also the 940-bp amplicon, whereas a 626-bp amplicon was consistently obtained with other European MON-1 strains. K26 PCR-restriction fragment length polymorphism, based on MON-1 K26 sequence polymorphism, gave 2 MON-1 subgroups. Application of the method may contribute to efficiently monitor VL.
- Published
- 2008
- Full Text
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50. In vitro activity of 10-deacetylbaccatin III against Leishmania donovani promastigotes and intracellular amastigotes.
- Author
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Georgopoulou K, Smirlis D, Bisti S, Xingi E, Skaltsounis L, and Soteriadou K
- Subjects
- Animals, Antiprotozoal Agents administration & dosage, Antiprotozoal Agents therapeutic use, Leishmania donovani physiology, Leishmaniasis drug therapy, Needles, Parasitic Sensitivity Tests, Plant Components, Aerial, Plant Extracts administration & dosage, Plant Extracts therapeutic use, Taxoids administration & dosage, Taxoids therapeutic use, Antiprotozoal Agents pharmacology, Leishmania donovani drug effects, Phytotherapy, Plant Extracts pharmacology, Taxoids pharmacology, Taxus
- Abstract
Current treatments for leishmaniasis are unsatisfactory due to their route of administration, toxicity and expense but, most importantly, to the developed resistance of Leishmania to first-line drugs. Therefore, the identification of new effective targeted drugs is an urgent need. Since many studies have shown that medicinal plants contain compounds active against protozoa we have undertaken a study aiming to determine the antileishmanial activity of the taxoid 10-deacetylbaccatin III, isolated from dried needles and small branches of the European yew tree (Taxus baccata). Interestingly, 10-deacetylbaccatin III was found to selectively inhibit the growth of L. DONOVANI intracellular amastigotes within J774 murine macrophages in vitro at nanomolar concentrations with an IC(50) value of 70 nM. Concentrations of 10-deacetylbaccatin III as high as 5 microM did not affect J774 murine macrophages whereas 20 nM of taxol, used as a control, was toxic to macrophages. The compound also inhibited the growth of L. donovani promastigotes but at higher concentrations with a maximum level of inhibition of 35 %. Taxol inhibited promastigote growth at micromolar concentrations. Comparison of the effect of 10-deacetylbaccatin III to that of taxol on cell cycle progression and cellular morphology showed that their mechanisms of action are different. The 10-deacetylbaccatin III-treated promastigotes were slightly arrested in the G2/M phase whereas taxol-treated cells were blocked in the G2/M phase. In addition 10-deacetylbaccatin III treatment, contrary to taxol, did not affect cellular morphology.
- Published
- 2007
- Full Text
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