scholarly journals Leishmania major Telomerase TERT Protein Has a Nuclear/Mitochondrial Eclipsed Distribution That Is Affected by Oxidative Stress

2014 ◽  
Vol 83 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Riward Campelo ◽  
Isabel Díaz Lozano ◽  
Katherine Figarella ◽  
Antonio Osuna ◽  
José Luis Ramírez
Keyword(s):  
Oxidative Stress ◽  
Mammalian Cells ◽  
Leishmania Major ◽  
Telomerase Activity ◽  
Kinetoplast Dna ◽  
Protein Subunit ◽  
Content Type ◽  
Human Parasite ◽  
Microscopy Techniques ◽  
Parasitic Cell

In its canonical role the reverse transcriptase telomerase recovers the telomeric repeats that are lost during DNA replication. Other locations and activities have been recently described for the telomerase protein subunit TERT in mammalian cells. In the present work, using biochemistry, molecular biology, and electron microscopy techniques, we found that in the human parasiteLeishmania major, TERT (and telomerase activity) shared locations between the nuclear, mitochondrial, and cytoplasmic compartments. Also, some telomerase activity and TERT protein could be found in ∼100-nm nanovesicles. In the mitochondrial compartment, TERT appears to be mainly associated with the kinetoplast DNA. WhenLeishmaniacells were exposed to H2O2, TERT changed its relative abundance and activity between the nuclear and mitochondrial compartments, with the majority of activity residing in the mitochondrion. Finally, overexpression of TERT inLeishmaniatransfected cells not only increased the parasitic cell growth rate but also increased their resistance to oxidative stress.

scholarly journals Evaluation of α,β-Unsaturated Ketones as Antileishmanial Agents

2015 ◽  
Vol 59 (6) ◽  
pp. 3598-3601 ◽  
Author(s):  
Miguel A. Vasquez ◽  
Eva Iniguez ◽  
Umashankar Das ◽  
Stephen M. Beverley ◽  
Linda J. Herrera ◽  
...  
Keyword(s):  
Murine Model ◽  
Mammalian Cells ◽  
Leishmania Major ◽  
Parasite Burden ◽  
Effective Concentration ◽  
Bioluminescent Imaging ◽  
Content Type ◽  
Unsaturated Ketones ◽  
Parasite Replication ◽  
20 Nm

ABSTRACTIn this study, we assessed the antileishmanial activity of 126 α,β-unsaturated ketones. The compounds NC901, NC884, and NC2459 showed high leishmanicidal activity for both the extracellular (50% effective concentration [EC50], 456 nM, 1,122 nM, and 20 nM, respectively) and intracellular (EC50, 1,870 nM, 937 nM, and 625 nM, respectively) forms ofLeishmania majorpropagated in macrophages, with little or no toxicity to mammalian cells. Bioluminescent imaging of parasite replication showed that all three compounds reduced the parasite burden in the murine model, with no apparent toxicity.

scholarly journals Zinc(II)-Dipicolylamine Coordination Complexes as Targeting and Chemotherapeutic Agents for Leishmania major

2016 ◽  
Vol 60 (5) ◽  
pp. 2932-2940 ◽  
Author(s):  
Douglas R. Rice ◽  
Paola Vacchina ◽  
Brianna Norris-Mullins ◽  
Miguel A. Morales ◽  
Bradley D. Smith
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Mammalian Cells ◽  
Leishmania Major ◽  
Parasite Burden ◽  
Coordination Complexes ◽  
Chemotherapeutic Agents ◽  
Selective Toxicity ◽  
Content Type

ABSTRACTCutaneous leishmaniasis is a neglected tropical disease that causes painful lesions and severe disfigurement. Modern treatment relies on a few chemotherapeutics with serious limitations, and there is a need for more effective alternatives. This study describes the selective targeting of zinc(II)-dipicolylamine (ZnDPA) coordination complexes towardLeishmania major, one of the species responsible for cutaneous leishmaniasis. Fluorescence microscopy ofL. majorpromastigotes treated with a fluorescently labeled ZnDPA probe indicated rapid accumulation of the probe within the axenic promastigote cytosol. The antileishmanial activities of eight ZnDPA complexes were measured using anin vitroassay. All tested complexes exhibited selective toxicity againstL. majoraxenic promastigotes, with 50% effective concentration values in the range of 12.7 to 0.3 μM. Similar toxicity was observed against intracellular amastigotes, but there was almost no effect on the viability of mammalian cells, including mouse peritoneal macrophages.In vivotreatment efficacy studies used fluorescence imaging to noninvasively monitor changes in the red fluorescence produced by an infection of mCherry-L. majorin a mouse model. A ZnDPA treatment regimen reduced the parasite burden nearly as well as the reference care agent, potassium antimony(III) tartrate, and with less necrosis in the local host tissue. The results demonstrate that ZnDPA coordination complexes are a promising new class of antileishmanial agents with potential for clinical translation.

scholarly journals Identification of Metal Dithiocarbamates as a Novel Class of Antileishmanial Agents

2015 ◽  
Vol 59 (4) ◽  
pp. 2144-2152 ◽  
Author(s):  
Dhiman Sankar Pal ◽  
Dipon Kumar Mondal ◽  
Rupak Datta
Keyword(s):  
Mammalian Cells ◽  
Leishmania Major ◽  
Lethal Dose ◽  
Parasite Burden ◽  
Intracellular Acidosis ◽  
Content Type ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Metal Dithiocarbamates ◽  
Morphological Deformities

ABSTRACTDithiocarbamates have emerged as potent carbonic anhydrase (CA) inhibitors in recent years. Given that CAs are important players in cellular metabolism, the objective of this work was to exploit the CA-inhibitory property of dithiocarbamates as a chemotherapeutic weapon against theLeishmaniaparasite. We report here strong antileishmanial activity of three hitherto unexplored metal dithiocarbamates, maneb, zineb, and propineb. They inhibited CA activity inLeishmania majorpromastigotes at submicromolar concentrations and resulted in a dose-dependent inhibition of parasite growth. Treatment with maneb, zineb, and propineb caused morphological deformities of the parasite andLeishmaniacell death with 50% lethal dose (LD50) values of 0.56 μM, 0.61 μM, and 0.27 μM, respectively. These compounds were even more effective against parasites growing in acidic medium, in which their LD50values were severalfold lower. Intracellular acidosis leading to apoptotic and necrotic death ofL. majorpromastigotes was found to be the basis of their leishmanicidal activity. Maneb, zineb, and propineb also efficiently reduced the intracellular parasite burden, suggesting that amastigote forms of the parasite are also susceptible to these metal dithiocarbamates. Interestingly, mammalian cells were unaffected by these compounds even at concentrations which are severalfold higher than their antileishmanial LD50s). Our data thus establish maneb, zineb, and propineb as a new class of antileishmanial compounds having broad therapeutic indices.

scholarly journals TbKAP6, a Mitochondrial HMG Box-Containing Protein in Trypanosoma brucei, Is the First Trypanosomatid Kinetoplast-Associated Protein Essential for Kinetoplast DNA Replication and Maintenance

2014 ◽  
Vol 13 (7) ◽  
pp. 919-932 ◽  
Author(s):  
Jianyang Wang ◽  
Valeria Pappas-Brown ◽  
Paul T. Englund ◽  
Robert E. Jensen
Keyword(s):  
Trypanosoma Brucei ◽  
Mammalian Cells ◽  
High Mobility ◽  
Kinetoplast Dna ◽  
Content Type ◽  
Hmg Box ◽  
Mitochondrial Nucleoids ◽  
Topo Ii

ABSTRACT Kinetoplast DNA (kDNA), the mitochondrial genome of trypanosomatids, is a giant planar network of catenated minicircles and maxicircles. In vivo kDNA is organized as a highly condensed nucleoprotein disk. So far, in Trypanosoma brucei , proteins involved in the maintenance of the kDNA condensed structure remain poorly characterized. In Crithidia fasciculata , some small basic histone H1-like k inetoplast- a ssociated p roteins (CfKAP) have been shown to condense isolated kDNA networks in vitro . High-mobility group (HMG) box-containing proteins, such as mitochondrial transcription factor A (TFAM) in mammalian cells and Abf2 in the budding yeast, have been shown essential for the packaging of mitochondrial DNA (mtDNA) into mitochondrial nucleoids, remodeling of mitochondrial nucleoids, gene expression, and maintenance of mtDNA. Here, we report that TbKAP6, a mitochondrial HMG box-containing protein, is essential for parasite cell viability and involved in kDNA replication and maintenance. The RNA interference (RNAi) depletion of TbKAP6 stopped cell growth. Replication of both minicircles and maxicircles was inhibited. RNAi or overexpression of TbKAP6 resulted in the disorganization, shrinkage, and loss of kDNA. Minicircle release, the first step in kDNA replication, was inhibited immediately after induction of RNAi, but it quickly increased 3-fold upon overexpression of TbKAP6. Since the release of covalently closed minicircles is mediated by a type II topoisomerase (topo II), we examined the potential interactions between TbKAP6 and topo II. Recombinant TbKAP6 (rTbKAP6) promotes the topo II-mediated decatenation of kDNA. rTbKAP6 can condense isolated kDNA networks in vitro . These results indicate that TbKAP6 is involved in the replication and maintenance of kDNA.

scholarly journals Human Telomerase RNA: Telomerase Component or More?

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 873 ◽  
Author(s):  
Maria Rubtsova ◽  
Olga Dontsova
Keyword(s):  
Oxidative Stress ◽  
Regulation Of Gene Expression ◽  
Telomerase Activity ◽  
Telomere Maintenance ◽  
Telomerase Rna ◽  
Biological Processes ◽  
Protein Subunit ◽  
Independent Components ◽  
Cellular Processes ◽  
Human Telomerase

Telomerase is a ribonucleoprotein complex that maintains the lengths of telomeres. Most studies of telomerase function have focused on the involvement of telomerase activation in the immortalization of cancer cells and cellular rejuvenation. However, some studies demonstrated that the results do not meet expectations for telomerase action in telomere maintenance. Recent results give reason to think that major telomerase components—the reverse transcriptase protein subunit and telomerase RNA—may participate in many cellular processes, including the regulation of apoptosis and autophagy, cell survival, pro-proliferative effects, regulation of gene expression, and protection against oxidative stress. However, the difficulties faced by scientist when researching telomerase component functions often reduce confidence in the minor effects observed in experiments. In this review, we focus on the analysis of the functions of telomerase components (paying more attention to the telomerase RNA component), both as a complex and as independent components, providing effects that are not associated with telomerase activity and telomere length maintenance. Despite the fact that the data on alternative roles of telomerase components look illusory, it would be wrong to completely reject the possibility of their involvement in other biological processes excluded from research/discussion. Investigations to improve the understanding of every aspect of the functioning of telomerase components will provide the basis for a more precise development of approaches to regulate cellular homeostasis, which is important for carcinogenesis and aging.

scholarly journals Cysteamine, an Endogenous Aminothiol, and Cystamine, the Disulfide Product of Oxidation, IncreasePseudomonas aeruginosaSensitivity to Reactive Oxygen and Nitrogen Species and Potentiate Therapeutic Antibiotics against Bacterial Infection

2018 ◽  
Vol 86 (6) ◽  
Author(s):  
Douglas J. Fraser-Pitt ◽  
Derry K. Mercer ◽  
Daniel Smith ◽  
Aleksandra Kowalczuk ◽  
Jennifer Robertson ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Infectious Disease ◽  
Pseudomonas Aeruginosa ◽  
Mammalian Cells ◽  
Mechanisms Of Action ◽  
Malarial Parasite ◽  
Nitrogen Species ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Selection Of

ABSTRACTCysteamine is an endogenous aminothiol produced in mammalian cells as a consequence of coenzyme A metabolism through the activity of the vanin family of pantetheinase ectoenzymes. It is known to have a biological role in oxidative stress, inflammation, and cell migration. There have been several reports demonstrating anti-infective properties targeting viruses, bacteria, and even the malarial parasite. We and others have previously described broad-spectrum antimicrobial and antibiofilm activities of cysteamine. Here, we go further to demonstrate redox-dependent mechanisms of action for the compound and how its antimicrobial effects are, at least in part, due to undermining bacterial defenses against oxidative and nitrosative challenges. We demonstrate the therapeutic potentiation of antibiotic therapy againstPseudomonas aeruginosain mouse models of infection. We also demonstrate potentiation of many different classes of antibiotics against a selection of priority antibiotic-resistant pathogens, including colistin (often considered an antibiotic of last resort), and we discuss how this endogenous antimicrobial component of innate immunity has a role in infectious disease that is beginning to be explored and is not yet fully understood.

scholarly journals Evaluating Aziridinyl Nitrobenzamide Compounds as Leishmanicidal Prodrugs

2013 ◽  
Vol 58 (1) ◽  
pp. 370-377 ◽  
Author(s):  
Andrew A. Voak ◽  
Karin Seifert ◽  
Nuala A. Helsby ◽  
Shane R. Wilkinson
Keyword(s):  
Mammalian Cells ◽  
Leishmania Major ◽  
Inhibitory Effect ◽  
Luciferase Reporter ◽  
Flavin Mononucleotide ◽  
Infection Model ◽  
Type I ◽  
Luciferase Reporter Gene ◽  
Content Type ◽  
Growth Inhibitory

ABSTRACTMany of the nitroaromatic agents used in medicine function as prodrugs and must undergo activation before exerting their toxic effects. In most cases, this is catalyzed by flavin mononucleotide (FMN)-dependent type I nitroreductases (NTRs), a class of enzyme absent from higher eukaryotes but expressed by bacteria and several eukaryotic microbes, including trypanosomes andLeishmania. Here, we utilize this difference to evaluate whether members of a library of aziridinyl nitrobenzamides have activity againstLeishmania major. Biochemical screens using purifiedL. majorNTR (LmNTR) revealed that compounds containing an aziridinyl-2,4-dinitrobenzyl core were effective substrates for the enzyme and showed that the 4-nitro group was important for this activity. To facilitate drug screening against intracellular amastigote parasites, we generated leishmanial cells that expressed the luciferase reporter gene and optimized a mammalian infection model in a 96-well plate format. A subset of aziridinyl-2,4-dinitrobenzyl compounds possessing a 5-amide substituent displayed significant growth-inhibitory properties against the parasite, with the most potent agents generating 50% inhibitory concentrations of <100 nM for the intracellular form. This antimicrobial activity was shown to be LmNTR specific sinceL. major NTR+/−heterozygote parasites were slightly resistance to most aziridinyl dinitrobenzyl agents tested. When the most potent leishmanicidal agents were screened against the mammalian cells in which the amastigote parasites were propagated, no growth-inhibitory effect was observed at concentrations of up to 100 μM. We conclude that the aziridinyl nitrobenzamides represent a new lead structure that may have the potential to treat leishmanial infections.

scholarly journals Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Susan L. Brockmeier ◽  
Crystal L. Loving ◽  
Tracy L. Nicholson ◽  
Jinhong Wang ◽  
Sarah E. Peters ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccine Trial ◽  
Streptococcus Suis ◽  
Protein Subunit ◽  
Content Type ◽  
Degree Of Protection ◽  
Wide Range ◽  
Associated Proteins ◽  
Clinical Protection ◽  
Cellular Immune

ABSTRACT Streptococcus suis is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of S. suis protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins. Five candidate proteins were selected for evaluation in a vaccine trial and administered both intranasally and intramuscularly with one of two different adjuvant formulations. Clinical protection was evaluated by subsequent intranasal challenge with virulent S. suis . While subunit vaccination with the S. suis proteins induced IgG antibodies to each individual protein and a cellular immune response to the pool of proteins and provided substantial protection from challenge with virulent S. suis , the immune response elicited and the degree of protection were dependent on the parenteral adjuvant given. Subunit vaccination induced IgG reactive against different S. suis serotypes, indicating a potential for cross protection.

scholarly journals Cellular Immune Response Induced by DNA Immunization of Mice with Drug Resistant Integrases of HIV-1 Clade A Offers Partial Protection against Growth and Metastatic Activity of Integrase-Expressing Adenocarcinoma Cells

2021 ◽  
Vol 9 (6) ◽  
pp. 1219
Author(s):  
Maria Isaguliants ◽  
Olga Krotova ◽  
Stefan Petkov ◽  
Juris Jansons ◽  
Ekaterina Bayurova ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cell ◽  
Cell Response ◽  
Mammalian Cells ◽  
Metastatic Potential ◽  
T Cell Response ◽  
Dna Immunization ◽  
Drug Resistant ◽  
Metastatic Activity ◽  
Hiv 1

Therapeutic DNA-vaccination against drug-resistant HIV-1 may hinder emergence and spread of drug-resistant HIV-1, allowing for longer successful antiretroviral treatment (ART) up-to relief of ART. We designed DNA-vaccines against drug-resistant HIV-1 based on consensus clade A integrase (IN) resistant to raltegravir: IN_in_r1 (L74M/E92Q/V151I/N155H/G163R) or IN_in_r2 (E138K/G140S/Q148K) carrying D64V abrogating IN activity. INs, overexpressed in mammalian cells from synthetic genes, were assessed for stability, route of proteolytic degradation, and ability to induce oxidative stress. Both were found safe in immunotoxicity tests in mice, with no inherent carcinogenicity: their expression did not enhance tumorigenic or metastatic potential of adenocarcinoma 4T1 cells. DNA-immunization of mice with INs induced potent multicytokine T-cell response mainly against aa 209–239, and moderate IgG response cross-recognizing diverse IN variants. DNA-immunization with IN_in_r1 protected 60% of mice from challenge with 4Tlluc2 cells expressing non-mutated IN, while DNA-immunization with IN_in_r2 protected only 20% of mice, although tumor cells expressed IN matching the immunogen. Tumor size inversely correlated with IN-specific IFN-γ/IL-2 T-cell response. IN-expressing tumors displayed compromised metastatic activity restricted to lungs with reduced metastases size. Protective potential of IN immunogens relied on their immunogenicity for CD8+ T-cells, dependent on proteasomal processing and low level of oxidative stress.

A manganese oxide nanozyme prevents the oxidative damage of biomolecules without affecting the endogenous antioxidant system

Nanoscale ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 3855-3863 ◽  
Author(s):  
Namrata Singh ◽  
Mohammed Azharuddin Savanur ◽  
Shubhi Srivastava ◽  
Patrick D'Silva ◽  
Govindasamy Mugesh
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Manganese Oxide ◽  
Antioxidant System ◽  
Mammalian Cells ◽  
Redox State ◽  
Stress Conditions ◽  
System P ◽  
Endogenous Antioxidant ◽  
Antioxidant Machinery

Multi-enzyme mimetic Mn3O4 nanoflowers (Mp) modulate the redox state of mammalian cells without altering the cellular antioxidant machinery under oxidative stress conditions.

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