scholarly journals Modulation of Cardiocyte Functional Activity by Antibodies against Trypanosoma cruzi Ribosomal P2 Protein C Terminus

2000 ◽  
Vol 68 (9) ◽  
pp. 5114-5119 ◽  
Author(s):  
P. Sepulveda ◽  
P. Liegeard ◽  
G. Wallukat ◽  
M. J. Levin ◽  
M. Hontebeyrie
Keyword(s):  
Trypanosoma Cruzi ◽  
Functional Activity ◽  
Molecular Mimicry ◽  
Host Cells ◽  
Cardiac Pathology ◽  
Epitope Recognition ◽  
C Terminus ◽  
P Proteins ◽  
Ribosomal P

ABSTRACT Antibodies against the Trypanosoma cruzi ribosomal P2β protein (TcP2β) have been associated with the chronic cardiac pathology of Chagas' disease in humans. Using synthetic peptides spanning the entire TcP2β molecule, we investigated their epitope recognition by antibodies from mice chronically infected with T. cruzi and from mice immunized with two recombinant TcP2βs. We found clear differences in epitope recognition between antibodies from T. cruzi-infected mice and mice immunized with two different recombinant TcP2βs associated with different schedules of immunization. Major epitopes recognized by antibodies from mice immunized with recombinant glutathioneS-transferase (GST) or histidine (Hist) fusion TcP2β (GST-TcP2β or Hist-TcP2β) are located in the central and hinge regions of the molecule. Nevertheless, mice immunized with Hist-TcP2β were also able to elicit antibodies against the TcP2β C terminus, a region which is highly conserved in both T. cruzi and mammal ribosomal P proteins. Strikingly, antibodies from infected animals recognized only the TcP2β C terminus. By using these antisera with distinct profiles of epitope recognition, it could be shown that only C terminus-specific antibodies were able to increase the beating frequency of cardiomyocytes from neonatal rats in vitro by selective stimulation of the β1-adrenergic receptor. Thus, antibodies against the TcP2β C terminus elicited in the absence of infection are able to modulate a functional activity of host cells through a molecular mimicry mechanism.

scholarly journals Molecular mimicry between the immunodominant ribosomal protein P0 of Trypanosoma cruzi and a functional epitope on the human beta 1-adrenergic receptor.

1995 ◽  
Vol 182 (1) ◽  
pp. 59-65 ◽  
Author(s):  
I Ferrari ◽  
M J Levin ◽  
G Wallukat ◽  
R Elies ◽  
D Lebesgue ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Adrenergic Receptor ◽  
Molecular Mimicry ◽  
Autoimmune Response ◽  
Extracellular Loop ◽  
Western Blots ◽  
Carboxy Terminal ◽  
Ribosomal Protein P0 ◽  
Positive Chronotropic Effect

Sera from chagasic patients possess antibodies recognizing the carboxy-terminal part of the ribosomal P0 protein of Trypanosoma cruzi and the second extracellular loop of the human beta 1-adrenergic receptor. Comparison of both peptides showed that they contain a pentapeptide with very high homology (AESEE in P0 and AESDE in the human beta 1-adrenergic receptor). Using a competitive immunoenzyme assay, recognition of the peptide corresponding to the second extracellular loop (H26R) was inhibited by both P0-14i (AAAESEEEDDDDDF) and P0-beta (AESEE). Concomitantly, recognition of P0-beta was inhibited with the H26R peptide. Recognition of P0 in Western blots was inhibited by P0-14i, P0-beta, and H26R, but not by a peptide corresponding to the second extracellular loop of the human beta 2-adrenergic receptor or by an unrelated peptide. Autoantibodies affinity purified with the immobilized H26R peptide were shown to exert a positive chronotropic effect in vitro on cardiomyocytes from neonatal rats. This effect was blocked by both the specific beta 1 blocker bisoprolol and the peptide P0-beta. These results unambiguously prove that T. cruzi is able to induce a functional autoimmune response against the cardiovascular human beta 1-adrenergic receptor through a molecular mimicry mechanism.

scholarly journals Neurotrophin Receptor TrkC Is an Entry Receptor for Trypanosoma cruzi in Neural, Glial, and Epithelial Cells

2011 ◽  
Vol 79 (10) ◽  
pp. 4081-4087 ◽  
Author(s):  
Craig Weinkauf ◽  
Ryan Salvador ◽  
Mercio PereiraPerrin
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Mammalian Cells ◽  
Chinese Hamster ◽  
Neuronal Cell ◽  
Host Cells ◽  
Neurotrophin Receptor ◽  
Content Type

ABSTRACTTrypanosoma cruzi, the agent of Chagas' disease, infects a variety of mammalian cells in a process that includes multiple cycles of intracellular division and differentiation starting with host receptor recognition by a parasite ligand(s). Earlier work in our laboratory showed that the neurotrophin-3 (NT-3) receptor TrkC is activated byT. cruzisurfacetrans-sialidase, also known as parasite-derived neurotrophic factor (PDNF). However, it has remained unclear whether TrkC is used byT. cruzito enter host cells. Here, we show that a neuronal cell line (PC12-NNR5) relatively resistant toT. cruzibecame highly susceptible to infection when overexpressing human TrkC but not human TrkB. Furthermore,trkCtransfection conferred an ∼3.0-fold intracellular growth advantage. Sialylation-deficient Chinese hamster ovarian (CHO) epithelial cell lines Lec1 and Lec2 also became much more permissive toT. cruziafter transfection with thetrkCgene. Additionally, NT-3 specifically blockedT. cruziinfection of the TrkC-NNR5 transfectants and of naturally permissive TrkC-bearing Schwann cells and astrocytes, as did recombinant PDNF. Two specific inhibitors of Trk autophosphorylation (K252a and AG879) and inhibitors of Trk-induced MAPK/Erk (U0126) and Akt kinase (LY294002) signaling, but not an inhibitor of insulin-like growth factor 1 receptor, abrogated TrkC-mediated cell invasion. Antibody to TrkC blockedT. cruziinfection of the TrkC-NNR5 transfectants and of cells that naturally express TrkC. The TrkC antibody also significantly and specifically reduced cutaneous infection in a mouse model of acute Chagas' disease. TrkC is ubiquitously expressed in the peripheral and central nervous systems, and in nonneural cells infected byT. cruzi, including cardiac and gastrointestinal muscle cells. Thus, TrkC is implicated as a functional PDNF receptor in cell entry, independently of sialic acid recognition, mediating broadT. cruziinfection bothin vitroandin vivo.

scholarly journals In Vitro and In Vivo Activities of E5700 and ER-119884, Two Novel Orally Active Squalene Synthase Inhibitors, against Trypanosoma cruzi

2004 ◽  
Vol 48 (7) ◽  
pp. 2379-2387 ◽  
Author(s):  
Julio A. Urbina ◽  
Juan Luis Concepcion ◽  
Aura Caldera ◽  
Gilberto Payares ◽  
Cristina Sanoja ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Public Health Problem ◽  
Squalene Synthase ◽  
Host Cells ◽  
In Vivo Studies ◽  
Inorganic Pyrophosphate ◽  
Orally Active

ABSTRACT Chagas' disease is a serious public health problem in Latin America, and no treatment is available for the prevalent chronic stage. Its causative agent, Trypanosoma cruzi, requires specific endogenous sterols for survival, and we have recently demonstrated that squalene synthase (SQS) is a promising target for antiparasitic chemotherapy. E5700 and ER-119884 are quinuclidine-based inhibitors of mammalian SQS that are currently in development as cholesterol- and triglyceride-lowering agents in humans. These compounds were found to be potent noncompetitive or mixed-type inhibitors of T. cruzi SQS with K i values in the low nanomolar to subnanomolar range in the absence or presence of 20 μM inorganic pyrophosphate. The antiproliferative 50% inhibitory concentrations of the compounds against extracellular epimastigotes and intracellular amastigotes were ca. 10 nM and 0.4 to 1.6 nM, respectively, with no effects on host cells. When treated with these compounds at the MIC, all of the parasite's sterols disappeared from the parasite cells. In vivo studies indicated that E5700 was able to provide full protection against death and completely arrested the development of parasitemia when given at a concentration of 50 mg/kg of body weight/day for 30 days, while ER-119884 provided only partial protection. This is the first report of an orally active SQS inhibitor that is capable of providing complete protection against fulminant, acute Chagas' disease.

scholarly journals Efficacy of Novel Pyrazolone Phosphodiesterase Inhibitors in Experimental Mouse Models of Trypanosoma cruzi

2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Julianna Siciliano de Araújo ◽  
Cristiane França da Silva ◽  
Denise da Gama Jaén Batista ◽  
Aline Nefertiti ◽  
Ludmila Ferreira de Almeida Fiuza ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Phosphodiesterase Inhibitors ◽  
Biological Properties ◽  
Host Cells ◽  
Mammalian Host ◽  
Intracellular Camp ◽  
Additive Interaction ◽  
Content Type

ABSTRACT Pyrazolones are heterocyclic compounds with interesting biological properties. Some derivatives inhibit phosphodiesterases (PDEs) and thereby increase the cellular concentration of cyclic AMP (cAMP), which plays a vital role in the control of metabolism in eukaryotic cells, including the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease (CD), a major neglected tropical disease. In vitro phenotypic screening identified a 4-bromophenyl-dihydropyrazole dimer as an anti-T. cruzi hit and 17 novel pyrazolone analogues with variations on the phenyl ring were investigated in a panel of phenotypic laboratory models. Potent activity against the intracellular forms (Tulahuen and Y strains) was obtained with 50% effective concentration (EC50) values within the 0.17 to 3.3 μM range. Although most were not active against bloodstream trypomastigotes, an altered morphology and loss of infectivity were observed. Pretreatment of the mammalian host cells with pyrazolones did not interfere with infection and proliferation, showing that the drug activity was not the result of changes to host cell metabolism. The pyrazolone NPD-227 increased the intracellular cAMP levels and was able to sterilize T. cruzi-infected cell cultures. Thus, due to its high potency and selectivity in vitro, and its additive interaction with benznidazole (Bz), NPD-227 was next assessed in the acute mouse model. Oral dosing for 5 days of NPD-227 at 10 mg/kg + Bz at 10 mg/kg not only reduced parasitemia (>87%) but also protected against mortality (>83% survival), hence demonstrating superiority to the monotherapy schemes. These data support these pyrazolone molecules as potential novel therapeutic alternatives for Chagas disease.

Could angiotensin-modulating drugs be relevant for the treatment of Trypanosoma cruzi infection? A systematic review of preclinical and clinical evidence

Parasitology ◽  
2019 ◽  
Vol 146 (07) ◽  
pp. 914-927 ◽  
Author(s):  
Thaiany G. Souza-Silva ◽  
Lívia F. Diniz ◽  
Ana Lia Mazzeti ◽  
Andrea A. S. Mendonça ◽  
Reggiani V. Gonçalves ◽  
...  
Keyword(s):  
Systematic Review ◽  
Trypanosoma Cruzi ◽  
Clinical Evidence ◽  
Renin Angiotensin System ◽  
Risk Of Bias ◽  
Host Cells ◽  
Angiotensin System ◽  
Preclinical And Clinical Studies ◽  
Cruzi Infection

AbstractAlthough leucocytes are targets of renin-angiotensin system (RAS) effector molecules and RAS-modulating drugs exert immunomodulatory effects, their impact onTrypanosoma cruziinfection remains poorly understood. By using the framework of a systematic review, we integrated the preclinical and clinical evidence to investigate the relevance of angiotensin-inhibiting drugs onT. cruziinfections. From a comprehensive and structured search in biomedical databases, only original studies were analysed. In preclinical and clinical studies, captopril, enalapril and losartan were RAS-modulating drugs used. The mainin vitrofindings indicated that these drugs increased parasite uptake per host cells, IL-12 expression by infected dendritic cells and IFN-γby T lymphocytes, in addition to attenuating IL-10 and IL-17 production by CD8 + T cells. In animal models, reduced parasitaemia, tissue parasitism, leucocytes infiltration and mortality were often observed inT. cruzi-infected animals receiving RAS-modulating drugs. In patients with Chagas’ disease, these drugs exerted a controversial impact on cytokine and hormone levels, and a limited effect on cardiovascular function. Considering a detailed evaluation of reporting and methodological quality, the current preclinical and clinical evidence is at high risk of bias, and we hope that our critical analysis will be useful in mitigating the risk of bias in further studies.

scholarly journals Anti-parasitic effect of novel amidines against Trypanosoma cruzi: phenotypic and in silico absorption, distribution, metabolism, excretion and toxicity analysis

2017 ◽  
Vol 3 ◽  
Author(s):  
ALINE SILVA DA GAMA NEFERTITI ◽  
MARCOS MEUSER BATISTA ◽  
PATRÍCIA BERNARDINO DA SILVA ◽  
EDUARDO CAIO TORRES-SANTOS ◽  
EDEZIO F. CUNHA-JÚNIOR ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
In Silico ◽  
Host Cells ◽  
Mammalian Host ◽  
Aromatic Molecules ◽  
Toxicity Analysis ◽  
Parasitic Effect ◽  
The Many ◽  
Discrete Typing Unit

SUMMARYNew more selective and potent drugs are urgently need to treat Chagas disease (CD). Among the many synthetic compounds evaluated againstTrypanosoma cruzi, aromatic amidines (AAs) and especially arylimidamides (AIAs) have potent activity against this parasite. Presently, the effect of four mono-amidines (DB2228, DB2229, DB2292 and DB2294), four diamidines (DB2232, DB2235, DB2251 and DB2253) and one AIA (DB2255) was screenedin vitroagainst different forms (bloodstream trypomastigotes – BT and intracellular forms) and strains from discrete typing unit (DTU) I and VI ofT. cruziand their cytotoxic profile on mammalian host cells. Except for DB2253, all molecules were as active as benznidazole (Bz), resulting in 50% of reduction in the number of alive BT, with EC50ranging from 2·7 to 10·1µmafter 24 h of incubation. DB2255 was also the most potent against amastigotes (Tulahuen strain) showing similar activity to that of Bz (3µm).In silicoabsorption, distribution, metabolism, excretion and toxicity analysis demonstrated probability of human intestinal adsorption, while mutagenicity and inhibition of hERG1 were not predicted, besides giving acceptable predicted volumes of distribution. Our findings contribute for better knowledge regarding the biological effect of this class of aromatic molecules againstT. cruziaiming to identify novel promising agent for CD therapy.

scholarly journals Spontaneous dormancy protects Trypanosoma cruzi during extended drug exposure

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Fernando J Sánchez-Valdéz ◽  
Angel Padilla ◽  
Wei Wang ◽  
Dylan Orr ◽  
Rick L Tarleton
Keyword(s):  
Trypanosoma Cruzi ◽  
Drug Treatment ◽  
Drug Exposure ◽  
Host Cells ◽  
New Host ◽  
Cytotoxic Compounds ◽  
Drug Treatments ◽  
Disease Agent

The ability of the Chagas disease agent Trypanosoma cruzi to resist extended in vivo exposure to highly effective trypanocidal compounds prompted us to explore the potential for dormancy and its contribution to failed drug treatments in this infection. We document the development of non-proliferating intracellular amastigotes in vivo and in vitro in the absence of drug treatment. Non-proliferative amastigotes ultimately converted to trypomastigotes and established infections in new host cells. Most significantly, dormant amastigotes were uniquely resistant to extended drug treatment in vivo and in vitro and could re-establish a flourishing infection after as many as 30 days of drug exposure. These results demonstrate a dormancy state in T. cruzi that accounts for the failure of highly cytotoxic compounds to completely resolve the infection. The ability of T. cruzi to establish dormancy throws into question current methods for identifying curative drugs but also suggests alternative therapeutic approaches.

scholarly journals Lupus antiribosomal P antisera contain antibodies to a small fragment of 28S rRNA located in the proposed ribosomal GTPase center.

1991 ◽  
Vol 174 (3) ◽  
pp. 507-514 ◽  
Author(s):  
J L Chu ◽  
N Brot ◽  
H Weissbach ◽  
K Elkon
Keyword(s):  
28S Rrna ◽  
Direct Role ◽  
Autoantibody Production ◽  
Antisense Orientation ◽  
Form Part ◽  
Rna Fragments ◽  
P Proteins ◽  
Ribosomal P ◽  
Made In

The ribosomal P proteins are necessary for GTPase activity during protein synthesis. In addition to antibodies to the P proteins, sera from lupus patients contain anti-rRNA activity. To determine whether lupus antiribosomal sera recognize the region of 28S rRNA recently proposed to form part of the ribosomal GTPase center, an rRNA fragment corresponding to nucleotides (nt) 1922-2020 was transcribed in vitro and tested for antigenicity. 18 of 24 (75%) lupus sera containing anti-P antibodies, but only 2 of 24 (8%) lupus sera without anti-P, immunoprecipitated this rRNA fragment (p less than 0.001). The binding was specific, since no significant differences were observed between anti-P positive and negative lupus sera in binding to the RNA fragment transcribed in the antisense orientation or to a control region of rRNA. The majority of sera tested protected a rRNA fragment of approximately 68 nucleotides. To evaluate the fine specificity of the anti-28S antibodies, deletions and site-directed mutations were made in the RNA fragment. The anti-28S antisera required nt 1944-1955 for recognition and were remarkably sensitive to destabilizing as well as nondestabilizing mutations in the stems of the RNA fragments. Detection of antiprotein and anti-RNA antibodies directed against a functionally related domain in the ribosome, together with the remarkable specificity of anti-28S antibodies, strongly suggests a direct role for this region of the ribosome in initiating and/or maintaining antiribosomal autoantibody production.

Antibodies against the carboxyl‐terminal end of the Trypanosoma cruzi ribosomal P proteins are pathogenic

2001 ◽  
Vol 15 (14) ◽  
pp. 2602-2612 ◽  
Author(s):  
Pablo López Bergami ◽  
Jorge Scaglione ◽  
Mariano Jorge Levin
Keyword(s):  
Trypanosoma Cruzi ◽  
Carboxyl Terminal ◽  
P Proteins ◽  
Ribosomal P

scholarly journals NK-Lysin and Its Shortened Analog NK-2 Exhibit Potent Activities against Trypanosoma cruzi

2003 ◽  
Vol 47 (2) ◽  
pp. 607-613 ◽  
Author(s):  
Thomas Jacobs ◽  
Heike Bruhn ◽  
Iris Gaworski ◽  
Bernhard Fleischer ◽  
Matthias Leippe
Keyword(s):  
Trypanosoma Cruzi ◽  
Antimicrobial Activities ◽  
Core Region ◽  
Host Cells ◽  
Cytotoxic Lymphocytes ◽  
Human Pathogen ◽  
Protozoan Parasites ◽  
Evolutionarily Conserved ◽  
Natural Peptides

ABSTRACT Antimicrobial peptides are widespread in nature and have been evolutionarily conserved as essential tools for combating a variety of pathogens. Among the plethora of natural peptides and synthetic analogs thereof studied in recent years for their antimicrobial activities, only a very few are known to be effective against protozoan parasites. In the present study we investigated the activity of NK-lysin, a broad-spectrum effector polypeptide of mammalian cytotoxic lymphocytes, against trypomastigotes of the human pathogen Trypanosoma cruzi in vitro. Moreover, the activity of a synthetic peptide named NK-2 that corresponds to the cationic core region of NK-lysin was tested in parallel against this parasite. T. cruzi was found to be highly susceptible to both peptides, as evidenced by inhibition of the mobility of trypomastigotes. The peptides rapidly permeabilized the plasma membrane of the parasite since micromolar concentrations resulted in the release of cytosolic enzymes within minutes. NK-lysin and NK-2 were even found to kill trypanosomes residing inside the human glioblastoma cell line 86HG39, but only NK-2 left the host cells apparently unharmed.

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