scholarly journals The trans-Sialidase from Trypanosoma cruzi Induces Thrombocytopenia during Acute Chagas' Disease by Reducing the Platelet Sialic Acid Contents

2005 ◽  
Vol 73 (1) ◽  
pp. 201-207 ◽  
Author(s):  
María Virginia Tribulatti ◽  
Juan Mucci ◽  
Nico Van Rooijen ◽  
María Susana Leguizamón ◽  
Oscar Campetella
Keyword(s):  
Sialic Acid ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Virulence Factor ◽  
Acid Content ◽  
Fluorescent Protein ◽  
Acute Infection ◽  
Sialic Acid Content ◽  
Platelet Surface ◽  
Acute Chagas Disease

ABSTRACT Strong thrombocytopenia is observed during acute infection with Trypanosoma cruzi, the parasitic protozoan agent of American trypanosomiasis or Chagas' disease. The parasite sheds trans-sialidase, an enzyme able to mobilize the sialyl residues on cell surfaces, which is distributed in blood and is a virulence factor. Since the sialic acid content on the platelet surface is crucial for determining the half-life of platelets in blood, we examined the possible involvement of the parasite-derived enzyme in thrombocytopenia induction. We found that a single intravenous injection of trans-sialidase into naïve mice reduced the platelet count by 50%, a transient effect that lasted as long as the enzyme remained in the blood. CD43−/− mice were affected to a similar extent. When green fluorescent protein-expressing platelets were treated in vitro with trans-sialidase, their sialic acid content was reduced together with their life span, as determined after transfusion into naïve animals. No apparent deleterious effect on the bone marrow was observed. A central role for Kupffer cells in the clearance of trans-sialidase-altered platelets was revealed after phagocyte depletion by administration of clodronate-containing liposomes and splenectomy. Consistent with this, parasite strains known to exhibit more trans-sialidase activity induced heavier thrombocytopenia. Finally, the passive transfer of a trans-sialidase-neutralizing monoclonal antibody to infected animals prevented the clearance of transfused platelets. Results reported here strongly support the hypothesis that the trans-sialidase is the virulence factor that, after depleting the sialic acid content of platelets, induces the accelerated clearance of the platelets that leads to the thrombocytopenia observed during acute Chagas' disease.

The Human Platelet Glycome and Its Variations Among Healthy Volunteers and Storage

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2300-2300
Author(s):  
Renata Grozovsky ◽  
Qiyong Peter Liu ◽  
Andrew Hanneman ◽  
David J. Ashline ◽  
Hailong Zhang ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Sialic Acid ◽  
Acid Content ◽  
Healthy Subjects ◽  
Sialic Acid Content ◽  
Platelet Surface ◽  
Standard Methods ◽  
Sialidase Activity ◽  
Platelet Storage ◽  
Terminal Galactose

Abstract Platelets have the shortest shelf-life of all major blood components and are the most difficult to store complicating platelet transfusion practices. Transfused fresh radiolabeled autologous platelets differ significantly in recovery and survival among healthy subjects, however the cause of the inter-individual differences remains unclear. We demonstrated that the loss of sialic acid from the surfaces of cold-stored and transfused platelets promotes their clearance by Ashwell Morell receptors. The loss of platelet surface sialic acid correlates with increases in surface sialidase activity during platelet storage. Here we investigated whether fresh platelets from individual donors exhibit differences in surface sialidase expression and glycan exposure and sialic acid content changes with storage. Methods Platelets were isolated by standard methods from the venous blood of healthy volunteers or from standard platelet concentrates (PCs) and analyzed by flow cytometry for surface β-galactose using FITC-conjugated E. cristagalli lectin (ECL). Platelet surface sialidase expression was measured by flow cytometry using antibodies to sialidases Neu1 and Neu3. Sialidase activities were assayed using standard methods, Platelet uptake by hepatocytes was measured by using the human hepatoma cell line HepG2. To further elucidate these issues in a structural biology context we performed baseline study of the N- and O-linked glycans and glycosphingolipids (GSLs) in platelets, and any structural changes observed during storage, by employing HPLC, LC-MS/(MS), and sequential mass spectrometry (MSn) approaches. Results We found that terminal galactose on freshly-isolated platelet glycoproteins varies considerably among healthy subjects: Seven of ten individuals had low levels of exposed galactose (15.3 ± 4.1, MFI) and three subjects exhibited significantly higher levels of terminal galactose as detected by flow cytometry using lectins. Reduced sialic acid content correlated with increased surface sialidase activity and expression. Platelets with high terminal galactose were ingested with a higher rate by HepG2 cells, i.e via Ashwell Morell receptors. Importantly, individuals with low sialic acid levels correlate with low platelet counts at steady state. Structural analysis revlealed that fresh platelet N-glycan pools include a significant amount of high-mannose (Man5-Man9) and asialo complex glycans, however, are dominated by a diverse range of complex sialylated structures with two to four antennae, up to four NeuAcs, and include antennary fucosylation, and five or more lactosamine extensions. The O-linked fractions are comprised of core-1 and core-2 glycans having zero, one, or two NeuAc residues. A significant decrease in sialylation during conventional platelet storage at room temperature was confirmed at the level of individual O-glycan structures. Quantitative analysis of the more structurally complex N-glycan pools is ongoing. Conclusion Our results show that fresh platelets from healthy individuals vary in surface sialidase activity and sialic acid content and exhibit a high complexity in glycan structures. Collectively we propose that individual platelet counts may be dependent on surface sialic acid content and that the surface sialic acid could represent a factor that affects the recovery and survival of transfused platelets. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Sialic Acid Content on Platelet Surface Glycoproteins Modulates Thrombin-Induced Activation

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3730-3730 ◽  
Author(s):  
Alexander Prete ◽  
Alexander Urtula ◽  
Renata Grozovsky
Keyword(s):  
Sialic Acid ◽  
Platelet Function ◽  
Acid Content ◽  
Lower Percentage ◽  
Wild Type ◽  
Sialic Acid Content ◽  
Platelet Surface ◽  
Activated Platelets ◽  
The Impact ◽  
Surface Glycoproteins

Abstract Platelets are fundamentally important in normal hemostasis and pathological thrombosis (i.e. cardiovascular diseases, stroke, etc.). Platelets mediate the initial first-step in hemostasis through surface glycoproteins like the GPIb-IX-V complex and integrin αIIbβ3 (GPIIbIIIa). Although the functions of platelet surface glycoproteins are well known, the roles of posttranslational modifications on those surface glycoproteins are poorly understood. We have recently shown that sialic acid is a key regulator of platelet survival. As platelets circulate and age in blood, they lose sialic acid and are rapidly cleared by the hepatocytes where they stimulate liver TPO production and consequently regulate thrombopoiesis. Here, we investigated the importance of glycosylation to platelet function by measuring the impact of sialic acid content on platelet responses to thrombin activation. Freshly isolated wild-type washed platelets were treated with a2-3, -6, -8 sialidase (neuraminidase, NA) to remove sialic acid from the platelet surface glycoproteins or with a competitive NA inhibitor, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (DANA) to prevent sialic acid loss by the action of sialidases. After treatment with both NA and DANA, platelets were activated with Thrombin (THR, 0.1U/mL). As controls, aliquots of freshly isolated wild-type washed platelets were left untreated (Rest), only treated with neuraminidase (NA) or activated with Thrombin (THR). First, we measured b-galactose exposure using RCA-I lectin to test the efficacy of treatments. As expected, NA treated platelets showed significantly higher RCA-I binding when compared to Rest, THR and DANA treated platelets. Noteworthy, RCA-I binding to THR activated platelets was higher than Rest or DANA + THR platelets. We next investigated the effect of NA and DANA treatments of platelet degranulation. Thrombin activated platelets showed high level of P-selectin surface exposure when compared to Rest platelets. NA treatment alone caused low P-selectin exposure (~18% positive platelets) and NA + THR treated platelets showed high levels of P-selectin similar to THR only treatment. Interestingly, DANA +THR platelets showed a lower percentage of P-selectin positive platelets when compared to THR activation only (~50% compared to ~85%). In platelets, thrombin signaling is mediated by PARs, G-protein-coupled receptors that trigger several intracellular pathways, including phosphorylation of several proteins. We next investigated if glycan remodeling of surface glycoproteins could alter the intracellular signaling triggered by Thrombin. Our data shows that NA + THR platelets have increased phosphorylated Akt when compared to THR alone and pretreatment with DANA dampens the phosphorylation signal triggered by THR activation. These data suggest that the glycosylation status of surface glycoproteins on platelets regulates thrombin-induced activation. Neuraminidases are lysosome-resident enzymes, they act primarily intracellularly but can also be recruited to the cell surface. Studies have shown that Neu1, one of the neuraminidase isoforms, regulates lysosome exocytosis by desialylation of LAMP1. Flow cytometry analysis of LAMP1 surface expression showed that THR activation induced LAMP1 surface exposure when compared to Rest. NA treatment did not affect LAMP1 surface exposure caused by THR, but DANA treatment completely blocked LAMP1 translocation to the surface, suggesting that Neuraminidase is a regulator of lysosomal exocytosis in platelets. Taken together, our data shows that sialic acid is a potential regulator of platelet function. More studies are needed to identify platelet glycoproteins affected by sialic acid changes. Nonetheless, these data illustrate that glycan remodeling is ideally suited for therapeutic manipulation to prevent undesired platelet activation. Disclosures No relevant conflicts of interest to declare.

scholarly journals Oral transmission of Chagas disease: importance of Trypanosoma cruzi biodeme in the intragastric experimental infection

2002 ◽  
Vol 44 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Edson Luiz P. CAMANDAROBA ◽  
Clarissa M. PINHEIRO LIMA ◽  
Sonia G. ANDRADE
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Acute Infection ◽  
Type I ◽  
Insect Vectors ◽  
Type Iii ◽  
Oral Transmission ◽  
Acute Chagas Disease ◽  
Intraperitoneal Inoculation ◽  
High Infectivity

Oral transmission of Trypanosoma cruzi has been suspected when epidemic episodes of acute infection were observed in areas devoid of domiciled insect vectors. Considering that the distribution of T. cruzi biodemes differs in sylvatic and domestic cycles, results of studies on biodemes can be of interest regarding oral transmission. The infectivity of T. cruzi strains of different biodemes was tested in mice subjected to infection by the digestive route (gavage). Swiss mice were infected either with the Peruvian strain (Biodeme Type I, Z2b) or the Colombian strain (Biodeme Type III, Z1, or T. cruzi I); for control, intraperitoneal inoculation was performed in a group of mice. The Colombian strain revealed a similar high infectivity and pathogenicity when either route of infection was used. However, the Peruvian strain showed contrasting levels of infectivity and pathogenicity, being high by intraperitoneal inoculation and low when the gastric route was used. The higher infectivity of the Colombian strain (Biodeme Type III) by gastric inoculation is in keeping with its role in the epidemic episodes of acute Chagas disease registered in the literature, since strains belonging to Biodeme III are most often found in sylvatic hosts.

129: Sialic Acid Content of Urinary TAMM-Horsfall Protein is Reduced in Interstitial Cystitis Patients

2007 ◽  
Vol 177 (4S) ◽  
pp. 44-45
Author(s):  
C. Lowell Parsons ◽  
Mahadevan Rajasekaran ◽  
Marianne Chenoweth ◽  
Paul Stein
Keyword(s):  
Sialic Acid ◽  
Interstitial Cystitis ◽  
Acid Content ◽  
Sialic Acid Content

Dynamics of T Cells Repertoire During Trypanosoma cruzi Infection and its Post-Treatment Modulation

2019 ◽  
Vol 26 (36) ◽  
pp. 6519-6543 ◽  
Author(s):  
Adriana Egui ◽  
Paola Lasso ◽  
Elena Pérez-Antón ◽  
M. Carmen Thomas ◽  
Manuel Carlos López
Keyword(s):  
Immune Response ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Cardiac Tissue ◽  
Acute Infection ◽  
Clinical Status ◽  
Chronic Phase ◽  
Parasite Load ◽  
Chronic Patients ◽  
Cruzi Infection

Chagas disease courses with different clinical phases and has a variable clinical presentation and progression. The acute infection phase mostly exhibits a non-specific symptomatology. In the absence of treatment, the acute phase is followed by a chronic phase, which is initially asymptomatic. This chronic asymptomatic phase of the disease is characterized by a fragile balance between the host’s immune response and the parasite replication. The loss of this balance is crucial for the progression of the sickness. The virulence and tropism of the T. cruzi infecting strain together to the inflammation processes in the cardiac tissue are the main factors for the establishment and severity of the cardiomyopathy. The efficacy of treatment in chronic Chagas disease patients is controversial. However, several studies carried out in chronic patients demonstrated that antiparasitic treatment reduces parasite load in the bloodstream and leads to an improvement in the immune response against the Trypanosoma cruzi parasite. The present review is mainly focused on the cellular patterns associated to the clinical status and the evolution of the disease in chronic patients, as well as the effectiveness of the treatment related to T. cruzi infection control. Therefore, an emphasis is placed on the dynamics of specific-antigens T cell subpopulations, their memory and activation phenotypes, their functionality and their contribution to pathogenesis or disease control, as well as their association with risk of congenital transmission of the parasite.

scholarly journals Differences in Sialic Acid Content of Human Interferons

1978 ◽  
Vol 41 (1) ◽  
pp. 175-178 ◽  
Author(s):  
J. Morser ◽  
J. P. Kabayo ◽  
D. W. Hutchinson
Keyword(s):  
Sialic Acid ◽  
Acid Content ◽  
Sialic Acid Content

scholarly journals Infection with Listeria monocytogenes impairs sialic acid addition to host cell glycoproteins.

1994 ◽  
Vol 180 (6) ◽  
pp. 2137-2145 ◽  
Author(s):  
M S Villanueva ◽  
C J Beckers ◽  
E G Pamer
Keyword(s):  
Listeria Monocytogenes ◽  
Sialic Acid ◽  
Host Cell ◽  
Mhc Class I ◽  
Acid Content ◽  
Class I ◽  
Sialic Acid Content ◽  
Infected Cells ◽  
The Impact ◽  
Glycosylation Defect

Listeria monocytogenes is a facultative intracellular bacterium that causes severe disease in neonates and immunocompromised adults. Although entry, multiplication, and locomotion of Listeria in the cytosol of infected cells are well described, the impact of such infection on the host cell is unknown. In this report, we investigate the effect of L. monocytogenes infection on MHC class I synthesis, processing, and intracellular trafficking. We show that L. monocytogenes infection interferes with normal processing of N-linked oligosaccharides on the major histocompatibility complex (MHC) class I heavy chain molecule, H-2Kd, resulting in a reduced sialic acid content. The glycosylation defect is more pronounced as the infection progresses and results from interference with the addition of sialic acid rather than its removal by a neuraminidase. The effect is found in two different cell lines and is not limited to MHC class I molecules since CD45, a surface glycoprotein, and LGP120, a lysosomal glycoprotein, are similarly affected by L. monocytogenes infection. The glycosylation defect is specific for infection by L. monocytogenes since neither Trypanosoma cruzi nor Yersinia enterocolitica, two other intracellular pathogens, reproduces the effect. The resultant hyposialylation of H-2Kd does not impair its surface expression in infected cells. Diminished sialic acid content of surface glycoproteins may enhance host-defense by increasing susceptibility to lysis and promoting clearance of Listeria-infected cells.

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