scholarly journals Evidence for the participation of the Ssp-3 antigen in the invasion of nonphagocytic mammalian cells by Trypanosoma cruzi.

1992 ◽  
Vol 175 (6) ◽  
pp. 1635-1641 ◽  
Author(s):  
S Schenkman ◽  
T Kurosaki ◽  
J V Ravetch ◽  
V Nussenzweig
Keyword(s):  
Monoclonal Antibodies ◽  
Trypanosoma Cruzi ◽  
Mammalian Cells ◽  
Surface Membrane ◽  
Fc Receptors ◽  
Transfected Cells ◽  
3T3 Fibroblasts ◽  
Parallel Increase ◽  
Membrane Antigens

Trypomastigotes of Trypanosoma cruzi have to invade mammalian cells in order to multiply. They bear on their plasma membrane a sialic acid-containing epitope (Ssp-3) defined by a series of monoclonal antibodies (mAbs). Previous investigations have shown that Fab fragments of these mAbs inhibit the attachment of trypomastigotes to 3T3 fibroblasts. To further define the role of Ssp-3 in invasion, here we use, as targets for infection, L cells and CHO cells stably transfected with cDNA coding for the mouse Fc receptors genes. When the trypomastigotes are incubated with small, nonagglutinating amounts of antibodies to Ssp-3, their attachment to the transfected cells is greatly enhanced, without a parallel increase in invasion. The enhancement in attachment is Fc mediated, since it is abolished by treatment of the transfected cells with mAbs to Fc receptors. In contrast, both attachment to, and invasion of, the transfected cells are increased if the parasites are incubated with polyclonal or monoclonal antibodies against T. cruzi surface membrane antigens other than Ssp-3. If, however, antibodies to Ssp-3 are added to the incubation mixtures containing any of the other anti-T. cruzi antibodies, the enhancement of invasion (but not of attachment) is reversed. These results suggest that Ssp-3-bearing molecules participate in the process of parasite internalization.

Trypanosoma cruzi heparin-binding proteins mediate the adherence of epimastigotes to the midgut epithelial cells of Rhodnius prolixus

Parasitology ◽  
2012 ◽  
Vol 139 (6) ◽  
pp. 735-743 ◽  
Author(s):  
F. O. R. OLIVEIRA ◽  
C. R. ALVES ◽  
F. SOUZA-SILVA ◽  
C. M. CALVET ◽  
L. M. C. CÔRTES ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Trypanosoma Cruzi ◽  
Mammalian Cells ◽  
Binding Proteins ◽  
Rhodnius Prolixus ◽  
Insect Vector ◽  
Heparin Binding ◽  
Molecular Masses ◽  
Pre Treatment

SUMMARYHeparin-binding proteins (HBPs) have been demonstrated in both infective forms of Trypanosoma cruzi and are involved in the recognition and invasion of mammalian cells. In this study, we evaluated the potential biological function of these proteins during the parasite-vector interaction. HBPs, with molecular masses of 65·8 kDa and 59 kDa, were isolated from epimastigotes by heparin affinity chromatography and identified by biotin-conjugated sulfated glycosaminoglycans (GAGs). Surface plasmon resonance biosensor analysis demonstrated stable receptor-ligand binding based on the association and dissociation values. Pre-incubation of epimastigotes with GAGs led to an inhibition of parasite binding to immobilized heparin. Competition assays were performed to evaluate the role of the HBP-GAG interaction in the recognition and adhesion of epimastigotes to midgut epithelial cells of Rhodnius prolixus. Epithelial cells pre-incubated with HBPs yielded a 3·8-fold inhibition in the adhesion of epimastigotes. The pre-treatment of epimastigotes with heparin, heparan sulfate and chondroitin sulfate significantly inhibited parasite adhesion to midgut epithelial cells, which was confirmed by scanning electron microscopy. We provide evidence that heparin-binding proteins are found on the surface of T. cruzi epimastigotes and demonstrate their key role in the recognition of sulfated GAGs on the surface of midgut epithelial cells of the insect vector.

scholarly journals Dual Role for Transforming Growth Factor β-Dependent Signaling in Trypanosoma cruzi Infection of Mammalian Cells

2000 ◽  
Vol 68 (4) ◽  
pp. 2077-2081 ◽  
Author(s):  
Belinda S. Hall ◽  
Miercio A. Pereira
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Trypanosoma Cruzi ◽  
Host Cell ◽  
Cell Lines ◽  
Mammalian Cells ◽  
Transforming Growth Factor ◽  
Growth Arrest ◽  
Transforming Growth Factor Β

ABSTRACT Expression of functional transforming growth factor β (TGF-β) receptors (TβR) is required for the invasion of mammalian cells by the protozoan parasite Trypanosoma cruzi. However, the precise role of this host cell signaling complex in T. cruzi infection is unknown. To investigate the role of the TGF-β signaling pathway, infection levels were studied in the mink lung epithelial cell lines JD1, JM2, and JM3. These cells express inducible mutant TβR1 proteins that cannot induce growth arrest in response to TGF-β but still transmit the signal for TGF-β-dependent gene expression. In the absence of mutant receptor expression, trypomastigotes invaded the cells at a low level. Induction of the mutant receptors caused an increase in infection in all three cell lines, showing that the requirement for TGF-β signaling at invasion can be divorced from TGF-β-induced growth arrest. TGF-β pretreatment of mink lung cells expressing wild-type TβR1 caused a marked enhancement of infection, but no enhancement was seen in JD1, JM2, and JM3 cells, showing that the ability of TGF-β to stimulate infection is associated with growth arrest. Likewise, expression of SMAD7 or SMAD2SA, inhibitors of TGF-β signaling, did not block infection by T. cruzi but did block the enhancement of infection by TGF-β. Taken together, these results show that there is a dual role for TGF-β signaling in T. cruzi infection. The initial invasion of the host cell is independent of both TGF-β-dependent gene expression and growth arrest, but TGF-β stimulation of infection requires a fully functional TGF-β signaling pathway.

Role of the p53 protein in cell proliferation as studied by microinjection of monoclonal antibodies

1984 ◽  
Vol 4 (2) ◽  
pp. 276-281
Author(s):  
W E Mercer ◽  
C Avignolo ◽  
R Baserga
Keyword(s):  
Cell Proliferation ◽  
Monoclonal Antibodies ◽  
Mammalian Cells ◽  
P53 Protein ◽  
S Phase ◽  
Human Cells ◽  
Antigenic Determinants ◽  
3T3 Cells ◽  
Species Specific

Two monoclonal antibodies against the p53 protein, PAb 122 and 200-47, were microinjected into mammalian cells as a probe to determine the role of the p53 protein in cell proliferation. PAb 122 recognizes the p53 proteins of mouse and human cells but not of hamster cells, whereas 200-47 recognizes the p53 proteins of mouse and hamster cells but not of human cells. The ability of these antibodies to inhibit serum-stimulated DNA synthesis of cells in culture correlates with their ability to recognize the species-specific antigenic determinants. More important, however, is the observation that microinjected PAb 122 inhibits the transition of Swiss 3T3 cells from G0 to S phase, but has no effect on the progression of these cells from mitosis to the S phase.

The schistosome in the mammalian host: understanding the mechanisms of adaptation

Parasitology ◽  
2007 ◽  
Vol 134 (11) ◽  
pp. 1477-1526 ◽  
Author(s):  
J. R. KUSEL ◽  
B. H. AL-ADHAMI ◽  
M. J. DOENHOFF
Keyword(s):  
Mammalian Cells ◽  
Surface Membrane ◽  
Membrane Rafts ◽  
Mammalian Host ◽  
Internal Organs ◽  
Parasite Communities ◽  
Mechanisms Of Adaptation ◽  
Future Work ◽  
The Relationship

SUMMARYIn this review, we envisage the host environment, not as a hostile one, since the schistosome thrives there, but as one in which the relationship between the two organisms consists of constant communication, through signalling mechanisms involving sense organs, surface glycocalyx, surface membrane and internal organs of the parasite, with host fluids and cells. The surface and secretions of the schistosome egg have very different properties from those of other parasite stages, but adapted for the dispersal of the eggs and for the preservation of host liver function. We draw from studies of mammalian cells and other organisms to indicate how further work might be carried out on the signalling function of the surface glycocalyx, the raft structure of the surface and existence of pores in the surface membrane, the repair of the surface membrane, the role of the membrane structure in ion channel function (including recent work on the actin cytoskeleton and calcium channels) and the possible role of P-glycoproteins in the adaptation of the parasite to its environment. We are speculative in some areas, such as the suggestions that variability in surface properties of schistosomes may relate to the existence of membrane rafts and that parasite communities may exhibit quorum sensing. This speculative approach is adopted with the hope that future work on the whole organisms and their interactions will be encouraged.

scholarly journals Regulation of ATP-induced calcium release in COS-7 cells by calcineurin

2000 ◽  
Vol 348 (1) ◽  
pp. 173-181 ◽  
Author(s):  
Arun BANDYOPADHYAY ◽  
Dong-Wook SHIN ◽  
Do Han KIM
Keyword(s):  
Mammalian Cells ◽  
Calcium Release ◽  
Calcineurin Inhibitors ◽  
Dependent Manner ◽  
Transfected Cells ◽  
High Level ◽  
Dose Dependent ◽  
Constitutively Active

Experiments were conducted to examine the role of calcineurin in regulating Ca2+ fluxes in mammalian cells. In COS-7 cells, increasing concentrations (1-10 μM) of ATP triggered intracellular Ca2+ release in a dose-dependent manner. Treatment of the cells with calcineurin inhibitors such as cyclosporin A (CsA), deltamethrin and FK506 resulted in an enhancement of ATP-induced intracellular Ca2+ release. Measurement of calcineurin-specific phosphatase activity in vitro demonstrated a high level of endogenous calcineurin activities in COS-7 cells, which was effectively inhibited by the addition of deltamethrin or CsA. The expression of constitutively active calcineurin (CnA∆CaMAI) inhibited the ATP-induced increase in intracellular Ca2+ concentration ([Ca2+]i), in both the presence and the absence of extracellular Ca2+. These results suggest that the constitutively active calcineurin prevented Ca2+ release from the intracellular stores. In the calcineurin-transfected cells, treatment with CsA restored the calcineurin-mediated inhibition of intracellular Ca2+ release. Protein kinase C-mediated phosphorylation of Ins(1,4,5)P3 receptor [Ins(1,4,5)P3R] was partly inhibited by the extracts prepared from the vector-transfected cells and completely inhibited by those from cells co-transfected with CnA∆CaMAI and calcineurin B. On the addition of 10 μM CsA, the inhibited phosphorylation of Ins(1,4,5)P3R was restored in both the vector-transfected cells and the calcineurin-transfected cells. These results show direct evidence that Ca2+ release through Ins(1,4,5)P3R in COS-7 cells is regulated by calcineurin-mediated dephosphorylation.

scholarly journals Role of the p53 protein in cell proliferation as studied by microinjection of monoclonal antibodies.

1984 ◽  
Vol 4 (2) ◽  
pp. 276-281 ◽  
Author(s):  
W E Mercer ◽  
C Avignolo ◽  
R Baserga
Keyword(s):  
Cell Proliferation ◽  
Monoclonal Antibodies ◽  
Mammalian Cells ◽  
P53 Protein ◽  
S Phase ◽  
Human Cells ◽  
Antigenic Determinants ◽  
3T3 Cells ◽  
Species Specific

Two monoclonal antibodies against the p53 protein, PAb 122 and 200-47, were microinjected into mammalian cells as a probe to determine the role of the p53 protein in cell proliferation. PAb 122 recognizes the p53 proteins of mouse and human cells but not of hamster cells, whereas 200-47 recognizes the p53 proteins of mouse and hamster cells but not of human cells. The ability of these antibodies to inhibit serum-stimulated DNA synthesis of cells in culture correlates with their ability to recognize the species-specific antigenic determinants. More important, however, is the observation that microinjected PAb 122 inhibits the transition of Swiss 3T3 cells from G0 to S phase, but has no effect on the progression of these cells from mitosis to the S phase.

scholarly journals Role of Trypanosoma cruzi nucleoside diphosphate kinase 1 in DNA-damage responses

2019 ◽  
Author(s):  
Chantal Reigada ◽  
Melisa Sayé ◽  
Fabio Di Girolamo ◽  
Edward A. Valera-Vera ◽  
Claudio A. Pereira ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Dna Repair ◽  
Trypanosoma Cruzi ◽  
Mammalian Cells ◽  
Spontaneous Mutation ◽  
Nucleoside Diphosphate Kinase ◽  
Dna Integrity ◽  
Dna Damage Responses

AbstractNME23/NDPK proteins are well conserved proteins found in all living organism. Besides their catalytic activity of nucleoside diphosphate kinase (NDPK) they are considered multifunctional, which were first characterized as non-metastatic proteins in mammalian cells. Later, increasing evidences placed NME/NDPK as proteins involved in DNA stability such as gene regulation and DNA-repair. TcNDPK1 is the canonical NDPK isoform present in the parasite Trypanosoma cruzi, orthologous to NME23-H1/H2 which has been shown to have in vitro nuclease activity and DNA-binding properties. In the present study we investigate the role of TcNDPK1 in DNA-damage responses using heterologous gene expression systems and over-expression in epimastigote cells. We found that different strains of bacteria, WT and ndk-mutants, expressing the enzyme decreased about 5 fold and 18 fold the spontaneous mutation rate, respectively. In addition, yeasts lacking the endogenous gene YNK1 (YNK1-) and expressing TcNDPK1, were significantly more resistant to different concentrations of hydrogen peroxide and were less sensible to UV radiation than controls. Parasites over-expressing TcNDPK1 were able to withstand different genotoxic stresses caused by hydrogen peroxide, phleomycin and hidroxyurea. In addition, under oxidative damage, TcNDPK1 over-expressing parasites presented lesser genomic damage and augmented levels of poly(ADP)ribose and poly(ADP)ribose polymerase, an enzyme involved in DNA repair. These results strongly suggest that TcNDPK1 is involved in the maintenance of parasite genomic-DNA integrity, thus, giving rise to a novel function.

scholarly journals Role of Glutathione in the Regulation of Cisplatin Resistance in Cancer Chemotherapy

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Helen H. W. Chen ◽  
Macus Tien Kuo
Keyword(s):  
Multidrug Resistance ◽  
Mammalian Cells ◽  
Cisplatin Resistance ◽  
Multidrug Resistance Protein ◽  
Transfected Cells ◽  
High Affinity ◽  
Multidrug Resistance Protein 2 ◽  
Resistance Protein ◽  
Rate Limiting

Three mechanisms have been proposed for the role of glutathione (GSH) in regulating cisplatin (CDDP) sensitivities that affects its ultimate cell-killing ability: (i) GSH may serve as a cofactor in facilitating multidrug resistance protein 2- (MRP2-) mediated CDDP efflux in mammalian cells, since MRP2-transfected cells were shown to confer CDDP resistance; (ii) GSH may serve as a redox-regulating cytoprotector based on the observations that many CDDP-resistant cells overexpress GSH and γ-glutamylcysteine synthesis (γ-GCS), the rate-limiting enzyme for GSH biosynthesis; (iii) GSH may function as a copper (Cu) chelator. Elevated GSH expression depletes the cellular bioavailable Cu pool, resulting in upregulation of the high-affinity Cu transporter (hCtr1) which is also a CDDP transporter. This has been demonstrated that overexpression of GSH by transfection with γ-GCS conferred sensitization to CDDP toxicity. This review describes how these three models were developed and critically reviews their importance to overall CDDP cytotoxicity in cancer cell treatments.

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