An increasing amount of research has led to the positioning of nucleoside diphosphate kinases (NDPK/NDK) as key metabolic enzymes among all organisms. They contribute to the maintenance the ...intracellular di- and tri- phosphate nucleoside homeostasis, but they also are involved in widely diverse processes such as gene regulation, apoptosis, signal transduction and many other regulatory roles.
Examine in depth the NDPKs of trypanosomatid parasites responsible for devastating human diseases (e.g., Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp.) which deserve special attention.
The earliest and latest advances in the topic were explored, focusing on trypanosomatid NDPK features, multifunctionality and suitability as molecular drug targets.
Trypanosomatid NDPKs appear to play functions different from their host counterparts. Evidences indicate that they would perform key roles in the parasite metabolism such as nucleotide homeostasis, drug resistance, DNA damage responses and gene regulation, as well as host-parasite interactions, infection, virulence and immune evasion, placing them as attractive pharmacological targets.
NDPKs are very interesting multifunctional enzymes. In the present review, the potential of trypanosomatid NDPKs was highlighted, raising awareness of their value not only with respect to parasite biology but also as molecular targets.
CONTEXT AND OBJECTIVE:Reconstruction of the knee ligament causes postoperative pain and delayed rehabilitation.
OBJECTIVE:The primary objective of this study was to evaluate the effect of a prolonged ...preoperative and postoperative pregabalin use for arthroscopic anterior cruciate ligament repair.
MATERIALS AND METHODS:Group 1 (N=25) patients received pregabalin 75 mg/d, and group 2 (N=25) received placebo, 7 days before and 7 days after surgery. Spinal anesthesia was performed using 0.5% hyperbaric bupivacaine (15 mg). The following were evaluatedpain intensity immediately after the surgery, and 12 hours, 24 hours, 1 week, 2 weeks, 1 month, and 2 months after the surgery using a Numerical Rating Scale; dose of postoperative supplementary analgesic for 2 months; time to first analgesic requirement; and side effects during 2 months. For supplementation, the participants received 1 g dipyrone; if there was no pain control, 100 mg ketoprofen was administered; if there was no effect, 100 mg tramadol was administered; and if there was no pain control, 5 mg intravenous morphine was administered until pain control.
RESULTS:There was no difference between the groups with regard to pain intensity (P=0.077). In the pregabalin group, morphine consumption was lower at 12 hours (P=0.039) and 24 hours (P=0.044) after surgery, and the consumption of tramadol and ketoprofen was lower 24 hours after surgery. There was no significant difference in the incidence of nausea and vomiting. Dizziness was higher in the pregabalin group (group 1=12 patients; group 2=3 patients; P=0.005).
DISCUSSION:A prolonged preoperative and postoperative pregabalin prescription for anterior cruciate ligament repair decreased the need for supplementary analgesics during the first 24 postoperative hours but increased dizziness.
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Arginine kinase catalyzes the reversible transphosphorylation between ADP and phosphoarginine which plays a critical role in the maintenance of cellular energy homeostasis. Arginine ...kinase from the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, meets the requirements to be considered as a potential therapeutic target for rational drug design including being absent in its mammalian hosts. In this study a group of polyphenolic compounds was evaluated as potential inhibitors of arginine kinase using molecular docking techniques. Among the analyzed compounds with the lowest free binding energy to the arginine kinase active site (<−6.96kcal/mol), resveratrol was chosen for subsequent assays. Resveratrol inhibits 50% of recombinant arginine kinase activity at 325μM. The trypanocidal effect of resveratrol was evaluated on the T. cruzi trypomastigotes bursting from infected CHO K1 cells, with IC50=77μM. Additionally epimastigotes overexpressing arginine kinase were 5 times more resistant to resveratrol compared to controls. Taking into account that: (1) resveratrol is considered as completely nontoxic; (2) is easily accessible due to its low market price; and (3) has as a well-defined target enzyme which is absent in the mammalian host, it is a promising compound as a trypanocidal drug for Chagas disease.
Trypanosoma cruzi
is the etiological agent of Chagas disease, a major health problem in Latin America. Polyamines are polycationic compounds that play a critical role as regulators of cell growth and ...differentiation. In contrast with other protozoa,
T. cruzi
is auxotrophic for polyamines because of its inability to synthesize putrescine due to the lack of both, arginine and ornithine decarboxylase; therefore, the intracellular availability of polyamines depends exclusively on transport processes. In this work, the polyamine transporter TcPAT12 was overexpressed in
T. cruzi
epimastigotes demonstrating that growth rates at different concentrations of polyamines strongly depend on the regulation of the polyamine transport. In addition, parasites overexpressing TcPAT12 showed a highly increased resistance to hydrogen peroxide and the trypanocidal drugs nifurtimox and benznidazole, which act by oxidative stress and interfering the synthesis of polyamine derivatives, respectively. Finally, the presence of putative polyamine transporters was analyzed in
T. cruzi
,
Trypanosoma brucei
, and
Leishmania major
genomes identifying 3–6 genes in these trypanosomatids.
Non-invasive in vivo human studies have always been of great importance owing to their advantages over the invasive studies. This research work also presents such a non-invasive study dealing with ...the penetration of two vitamin derivatives: retinyl acetate and alpha-tocopheryl acetate, into the stratum corneum of two groups of study participants categorized based on age as young (average age of 24.1 ± 3.3 years old) and elderly groups (average age of 68 ± 5.8 years old). According to the increase of age it is expected that intrinsic alterations may occur in the stratum corneum. Understanding these alterations is relevant to the knowledge of the differences between stratum corneum as a function of age-dependence thus, leading to the development of new specific products for ageing. The penetration of these derivatives was semi-quantitatively analyzed using confocal Raman spectroscopic technique with 3510 Skin Composition Analyzer (River Diagnostics, Rotterdam, The Netherlands) with a diode laser of 785 nm wavelength and 26 mW power. The analysis was done in the extended fingerprint region (1800 - 400 cm−1) for the stratum corneum region of the skin considering the depths from surface up to 24 μm. The results of this study clearly indicated that these two vitamin derivatives penetrated significantly into the stratum corneum of both study groups and their penetration was mainly affected by the composition of SC and their physico-chemical properties. The penetration profile of the alpha-tocopheryl acetate displays significant statistical difference (p < 0.05) between groups from surface up to 12 μm.
NME23/NDPKs are well conserved proteins found in all living organisms. In addition to being nucleoside diphosphate kinases (NDPK), they are multifunctional enzymes involved in different processes ...such as DNA stability, gene regulation and DNA repair among others. TcNDPK1 is the canonical NDPK isoform present in Trypanosoma cruzi, which has nuclease activity and DNA-binding properties in vitro.
In the present study we explored the role of TcNDPK1 in DNA damage responses.
TcNDPK1 was expressed in mutant bacteria and yeasts and over-expressed in epimastigotes. Mutation frequencies, tolerance to genotoxic agents and activity of DNA repair enzymes were evaluated.
Bacteria decreased about 15-folds the spontaneous mutation rate and yeasts were more resistant to hydrogen peroxide and to UV radiation than controls. Parasites overexpressing TcNDPK1 were able to withstand genotoxic stresses caused by hydrogen peroxide, phleomycin and hidroxyurea. They also presented less genomic damage and augmented levels of poly(ADP)ribose and poly(ADP)ribose polymerase, an enzyme involved in DNA repair.
These results strongly suggest a novel function for TcNDPK1; its involvement in the maintenance of parasite's genome integrity.
Trypanosomatid parasites represent a major health issue affecting hundreds of million people worldwide, with clinical treatments that are partially effective and/or very toxic. They are responsible ...for serious human and plant diseases including Trypanosoma cruzi (Chagas disease), Trypanosoma brucei (Sleeping sickness), Leishmania spp. (Leishmaniasis), and Phytomonas spp. (phytoparasites). Both, animals and trypanosomatids lack the biosynthetic riboflavin (vitamin B2) pathway, the vital precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) cofactors. While metazoans obtain riboflavin from the diet through RFVT/SLC52 transporters, the riboflavin transport mechanisms in trypanosomatids still remain unknown.
Here, we show that riboflavin is imported with high affinity in Trypanosoma cruzi, Trypanosoma brucei, Leishmania (Leishmania) mexicana, Crithidia fasciculata and Phytomonas Jma using radiolabeled riboflavin transport assays. The vitamin is incorporated through a saturable carrier-mediated process. Effective competitive uptake occurs with riboflavin analogs roseoflavin, lumiflavin and lumichrome, and co-factor derivatives FMN and FAD. Moreover, important biological processes evaluated in T. cruzi (i.e. proliferation, metacyclogenesis and amastigote replication) are dependent on riboflavin availability. In addition, the riboflavin competitive analogs were found to interfere with parasite physiology on riboflavin-dependent processes. By means of bioinformatics analyses we identified a novel family of riboflavin transporters (RibJ) in trypanosomatids. Two RibJ members, TcRibJ and TbRibJ from T. cruzi and T. brucei respectively, were functionally characterized using homologous and/or heterologous expression systems.
The RibJ family represents the first riboflavin transporters found in protists and the third eukaryotic family known to date. The essentiality of riboflavin for trypanosomatids, and the structural/biochemical differences that RFVT/SLC52 and RibJ present, make the riboflavin transporter -and its downstream metabolism- a potential trypanocidal drug target.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The post genomic era revealed the need for developing better performing, easier to use and more sophisticated genetic manipulation tools for the study of Trypanosoma cruzi, the etiological agent of ...Chagas disease. In this work a series of plasmids that allow genetic manipulation of this protozoan parasite were developed. First of all we focused on useful tools to establish selection strategies for different strains and which can be employed as expression vectors. On the other hand molecular building blocks in the form of diverse selectable markers, modifiable fluorescent protein and epitope-tag coding sequences were produced. Both types of modules were harboured in backbone molecules conceived to offer multiple construction and sub-cloning strategies. These can be used to confer new properties to already available genetic manipulation tools or as starting points for whole novel designs. The performance of each plasmid and building block was determined independently. For illustration purposes, some simple direct practical applications were conducted.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The purpose of this study was to assess the in vitro antimicrobial activity of alkaloid-enriched extracts from Prosopis juliflora (Fabaceae) pods in order to evaluate them as feed additives for ...ruminants. As only the basic chloroformic extract (BCE), whose main constituents were juliprosopine (juliflorine), prosoflorine and juliprosine, showed Gram-positive antibacterial activity against Micrococcus luteus (MIC = 25 μg/mL), Staphylococcus aureus (MIC = 50 μg/mL) and Streptococcus mutans (MIC = 50 μg/mL), its influence on ruminal digestion was evaluated using a semi-automated in vitro gas production technique, with monensin as the positive control. Results showed that BCE has decreased gas production as efficiently as monensin after 36 h of fermentation, revealing its positive influence on gas production during ruminal digestion. Since P. juliflora is a very affordable plant, this study points out this alkaloid enriched extract from the pods of Prosopis juliflora as a potential feed additive to decrease gas production during ruminal digestion.
Trypanosoma cruzi, the etiological agent of Chagas disease, uses proline as its main carbon source, essential for parasite growth and stage differentiation in epimastigotes and amastigotes. Since ...proline is involved in many essential biological processes in T. cruzi, its transport and metabolism are interesting drug targets.
Four synthetic proline analogues (ITP-1B/1C/1D/1G) were evaluated as inhibitors of proline transport mediated through the T. cruzi proline permease TcAAAP069. The trypanocidal activity of the compounds was also assessed.
The compounds ITP-1B and ITP-1G inhibited proline transport mediated through TcAAAP069 permease in a dose-dependent manner. The analogues ITP-1B, -1D and -1G had trypanocidal effect on T. cruzi epimastigotes with IC50 values between 30 and 40μM. However, only ITP-1G trypanocidal activity was related with its inhibitory effect on TcAAAP069 proline transporter. Furthermore, this analogue strongly inhibited the parasite stage differentiation from epimastigote to metacyclic trypomastigote. Finally, compounds ITP-1B and ITP-1G were also able to inhibit the transport mediated by other permeases from the same amino acid permeases family, TcAAAP.
It is possible to design synthetic amino acid analogues with trypanocidal activity. The compound ITP-1G is an interesting starting point for new trypanocidal drug design which is also an inhibitor of transport of amino acids and polyamines mediated by permeases from the TcAAAP family, such as proline transporter TcAAAP069 among others.
The Trypanosoma cruzi amino acid transporter family TcAAAP constitutes a multiple and promising therapeutic target for the development of new treatments against Chagas disease.
•Synthetic proline analogues are proposed as new trypanocidal drugs.•One of this analogues inhibits amino acid transport and has trypanocidal action.•The TcAAAP transporter family constitutes a promising multiple therapeutic target.
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