Trypanosoma cruzi trans-Sialidase in Complex with a Neutralizing Antibody: Structure/Function Studies towards the Rational Design of Inhibitors

ABSTRACT Chagas' disease results from infection with Trypanosoma cruzi, a protozoan parasite that establishes systemic intracellular infection after mucosal invasion. We hypothesized that ideal vaccines for mucosally invasive, intracellular pathogens like T. cruzi should induce mucosal type 2 immunity for optimal induction of protective secretory immunoglobulin A (IgA) and systemic type 1 immunity protective against intracellular replication. However, differential mucosal and systemic immune memory could be difficult to induce because of reciprocal inhibitory actions between type 1 and type 2 responses. To test our hypotheses, we investigated the protective effects of type 1 and type 2 biased vaccines against mucosal and systemic T. cruzi challenges. Intranasal vaccinations were given with recombinant interleukin-12 (IL-12)- and IL-4-neutralizing antibody (Ab) for type 1 immune bias, or recombinant IL-4 and gamma interferon-neutralizing Ab for type 2 immune bias. Cytokine RNA and protein studies confirmed that highly polarized memory immune responses were induced by our vaccination protocols. Survival after virulent subcutaneous T. cruzi challenge was used to assess systemic protection. Mucosal protection was assessed by measuring the relative inhibition of parasite replication in mucosal tissues early after oral T. cruzi challenge, using both PCR and quantitative culture techniques. As expected, only type 1 responses protected against systemic challenges (P < 0.01). However, contrary to our original hypothesis, type 1 responses optimally protected against mucosal challenges as well (P < 0.05). Type 1 and type 2 biased vaccines induced similar secretory IgA responses. We conclude that future vaccines for T. cruzi and possibly other mucosally invasive, intracellular pathogens should induce both mucosal and systemic type 1 immunity.

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KBE009: A Bestatin-Like Inhibitor of the Trypanosoma cruzi Acidic M17 Aminopeptidase With In Vitro Anti-Trypanosomal Activity

Life ◽

10.3390/life11101037 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1037

Author(s):

Jorge González-Bacerio ◽

Irina Arocha ◽

Mirtha Elisa Aguado ◽

Yanira Méndez ◽

Sabrina Marsiccobetre ◽

...

Keyword(s):

Trypanosoma Cruzi ◽

Rational Design ◽

Specific Effect ◽

Dermal Fibroblasts ◽

Aminopeptidase Activity ◽

Geometrical Shape ◽

Starting Point ◽

Insight Into ◽

Leucyl Aminopeptidase

Chagas disease, caused by the kinetoplastid parasite Trypanosoma cruzi, is a human tropical illness mainly present in Latin America. The therapies available against this disease are far from ideal. Proteases from pathogenic protozoan have been considered as good drug target candidates. T. cruzi acidic M17 leucyl-aminopeptidase (TcLAP) mediates the major parasite’s leucyl-aminopeptidase activity and is expressed in all parasite stages. Here, we report the inhibition of TcLAP (IC50 = 66.0 ± 13.5 µM) by the bestatin-like peptidomimetic KBE009. This molecule also inhibited the proliferation of T. cruzi epimastigotes in vitro (EC50 = 28.1 ± 1.9 µM) and showed selectivity for the parasite over human dermal fibroblasts (selectivity index: 4.9). Further insight into the specific effect of KBE009 on T. cruzi was provided by docking simulation using the crystal structure of TcLAP and a modeled human orthologous, hLAP3. The TcLAP-KBE009 complex is more stable than its hLAP3 counterpart. KBE009 adopted a better geometrical shape to fit into the active site of TcLAP than that of hLAP3. The drug-likeness and lead-likeness in silico parameters of KBE009 are satisfactory. Altogether, our results provide an initial insight into KBE009 as a promising starting point compound for the rational design of drugs through further optimization.

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Publisher Correction: A glycoprotein B-neutralizing antibody structure at 2.8 Å uncovers a critical domain for herpesvirus fusion initiation

Nature Communications ◽

10.1038/s41467-020-18385-w ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Stefan L. Oliver ◽

Yi Xing ◽

Dong-Hua Chen ◽

Soung Hun Roh ◽

Grigore D. Pintilie ◽

...

Keyword(s):

Neutralizing Antibody ◽

Glycoprotein B ◽

Critical Domain ◽

Antibody Structure

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Elucidation of the paratope of scFv-8H9D4, a PAI-1 neutralizing antibody derivative

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613545 ◽

2003 ◽

Vol 89 (01) ◽

pp. 74-82 ◽

Cited By ~ 3

Author(s):

Koen Verbeke ◽

Ann Gils ◽

Jean-Marie Stassen ◽

Paul Declerck

Keyword(s):

Rational Design ◽

Three Dimensional ◽

Neutralizing Antibody ◽

Plasminogen Activator Inhibitor ◽

Site Directed Mutagenesis ◽

Dimensional Structure ◽

Single Chain ◽

Plasminogen Activator Inhibitor 1 ◽

Activator Inhibitor ◽

Pai 1

SummaryInterfering with increased levels of plasminogen activator inhibitor-1 (PAI-1) might offer new therapeutic strategies for a variety of cardiovascular diseases. Inactivation of PAI-1 can be accomplished by a number of monoclonal antibodies (MA), including MA-8H9D4. In a previous study, a single-chain variable fragment (scFv-8H9D4) was cloned and found to have the same properties as the parental MA-8H9D4. In the present study, we identified the residues of scFv-8H9D4 that contribute significantly to the paratope. The complementarity determining region 3 from the heavy (H3) and the light (L3) chain were analysed through site-directed mutagenesis. Out of twelve mutations, only four residues appeared to contribute to the paratope. The affinity of scFv-8H9D4-H3-L97D for PAI-1 was 38-fold decreased (KA = 4.8 ± 0.2 × 107 M–1 vs. 1.8 ± 0.7 × 109 M–1 for scFv-8H9D4) whereas scFv-8H9D4-H3-R98Y did not bind to PAI-1. The affinities of scFv-8H9D4-L3-Y91S and scFv-8H9D4-L3-F94D for PAI-1 were 9- and 5-fold reduced, respectively, whereas the combined mutation resulted in an 86-fold decreased affinity (KA = 2.1 ± 0.2 × 107 M–1).In accordance with the affinity data, these mutants had no, or a reduced, PAI-1 inhibitory capacity, confirming that these four particular residues form the major interaction site of scFv-8H9D4 with PAI-1. In combination with the three-dimensional structure, these data contribute to the rational design of PAI-1 neutralizing compounds.

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Virtual Screening Based on QSAR and Molecular Docking of Possible Inhibitors Targeting Chagas CYP51

Journal of Chemistry ◽

10.1155/2021/6640624 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

J. Cotuá ◽

H. LLinás ◽

S. Cotes

Keyword(s):

Virtual Screening ◽

Trypanosoma Cruzi ◽

Regression Models ◽

Rational Design ◽

Linear Regression Models ◽

Wide Range ◽

London Dispersion ◽

Reduced Toxicity ◽

Therapeutic Alternatives ◽

London Dispersion Forces

Chagas is a neglected tropical disease caused by the parasite Trypanosoma cruzi with no effective treatment in all its forms. There is a need to find more effective therapeutic alternatives with reduced toxicity. In this contribution, multiple linear regression models were used to identify the molecular descriptors that best describe the inhibitory activity of 52 fenarimol analogues against Trypanosoma cruzi. The topological, physicochemical, thermodynamic, electronic, and charge descriptors were evaluated to cover a wide range of properties that frequently encode biological activity. A model with high predictive value was obtained based on geometrical descriptors and descriptors encoding hydrophobicity and London dispersion forces as necessary for the inhibition of Trypanosoma cruzi-CYP51. Docking methodology was implemented to evaluate molecular interactions in silico. The virtual screening results in this study can be used for rational design of new analogues with improved activity against Chagas disease.

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Search of Allosteric Inhibitors and Associated Proteins of an AKT-like Kinase from Trypanosoma cruzi

International Journal of Molecular Sciences ◽

10.3390/ijms19123951 ◽

2018 ◽

Vol 19 (12) ◽

pp. 3951 ◽

Cited By ~ 1

Author(s):

Rodrigo Ochoa ◽

Cristian Rocha-Roa ◽

Marcel Marín-Villa ◽

Sara Robledo ◽

Rubén Varela-M

Keyword(s):

Trypanosoma Cruzi ◽

Signaling Pathway ◽

Intracellular Signaling ◽

Rational Design ◽

Interaction Network ◽

Pleckstrin Homology Domain ◽

Intracellular Signaling Pathway ◽

Protein Protein Interaction ◽

Associated Proteins

Proteins associated to the PI3K/AKT/mTOR signaling pathway are widely used targets for cancer treatment, and in recent years they have also been evaluated as putative targets in trypanosomatids parasites, such as Trypanosoma cruzi. Here, we performed a virtual screening approach to find candidates that can bind regions on or near the Pleckstrin homology domain of an AKT-like protein in T. cruzi. The compounds were also evaluated in vitro. The in silico and experimental results allowed us to identify a set of compounds that can potentially alter the intracellular signaling pathway through the AKT-like kinase of the parasite; among them, a derivative of the pyrazolopyridine nucleus with an IC50 of 14.25 ± 1.00 μM against amastigotes of T. cruzi. In addition, we built a protein–protein interaction network of T. cruzi to understand the role of the AKT-like protein in the parasite, and look for additional proteins that can be postulated as possible novel molecular targets for the rational design of compounds against T. cruzi.

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Prospects of and Barriers to the Development of Epitope-Based Vaccines against Human Metapneumovirus

Pathogens ◽

10.3390/pathogens9060481 ◽

2020 ◽

Vol 9 (6) ◽

pp. 481

Author(s):

Ekaterina Stepanova ◽

Victoria Matyushenko ◽

Larisa Rudenko ◽

Irina Isakova-Sivak

Keyword(s):

T Cell ◽

Rational Design ◽

Current Knowledge ◽

Neutralizing Antibody ◽

The Elderly ◽

Human Metapneumovirus ◽

Cd4 T Cell ◽

T Cell Epitopes ◽

Respiratory Illnesses ◽

Protective Epitope

Human metapneumovirus (HMPV) is a major cause of respiratory illnesses in children, the elderly and immunocompromised patients. Although this pathogen was only discovered in 2001, an enormous amount of research has been conducted in order to develop safe and effective vaccines to prevent people from contracting the disease. In this review, we summarize current knowledge about the most promising experimental B- and T-cell epitopes of human metapneumovirus for the rational design of HMPV vaccines using vector delivery systems, paying special attention to the conservation of these epitopes among different lineages/genotypes of HMPV. The prospects of the successful development of an epitope-based HMPV vaccine are discussed in the context of recent findings regarding HMPV’s ability to modulate host immunity. In particular, we discuss the lack of data on experimental human CD4 T-cell epitopes for HMPV despite the role of CD4 lymphocytes in both the induction of higher neutralizing antibody titers and the establishment of CD8 memory T-cell responses. We conclude that current research should be focused on searching for human CD4 T-cell epitopes of HMPV that can help us to design a safe and cross-protective epitope-based HMPV vaccine.

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A glycoprotein B-neutralizing antibody structure at 2.8 Å uncovers a critical domain for herpesvirus fusion initiation

Nature Communications ◽

10.1038/s41467-020-17911-0 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 3

Author(s):

Stefan L. Oliver ◽

Yi Xing ◽

Dong-Hua Chen ◽

Soung Hun Roh ◽

Grigore D. Pintilie ◽

...

Keyword(s):

Neutralizing Antibody ◽

Glycoprotein B ◽

Critical Domain ◽

Antibody Structure

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The Thiol-polyamine Metabolism of Trypanosoma cruzi: Molecular Targets and Drug Repurposing Strategies

Current Medicinal Chemistry ◽

10.2174/0929867325666180926151059 ◽

2019 ◽

Vol 26 (36) ◽

pp. 6614-6635 ◽

Cited By ~ 5

Author(s):

Alan Talevi ◽

Carolina Carrillo ◽

Marcelo Comini

Keyword(s):

Drug Discovery ◽

Trypanosoma Cruzi ◽

Rational Design ◽

Biological Activities ◽

Public Health Problem ◽

Drug Repurposing ◽

Polyamine Metabolism ◽

Pharmacological Intervention ◽

Mammalian Host ◽

Essential Components

Chagas´ disease continues to be a challenging and neglected public health problem in many American countries. The etiologic agent, Trypanosoma cruzi, develops intracellularly in the mammalian host, which hinders treatment efficacy. Progress in the knowledge of parasite biology and host-pathogen interaction has not been paralleled by the development of novel, safe and effective therapeutic options. It is then urgent to seek for novel therapeutic candidates and to implement drug discovery strategies that may accelerate the discovery process. The most appealing targets for pharmacological intervention are those essential for the pathogen and, whenever possible, absent or significantly different from the host homolog. The thiol-polyamine metabolism of T. cruzi offers interesting candidates for a rational design of selective drugs. In this respect, here we critically review the state of the art of the thiolpolyamine metabolism of T. cruzi and the pharmacological potential of its components. On the other hand, drug repurposing emerged as a valid strategy to identify new biological activities for drugs in clinical use, while significantly shortening the long time and high cost associated with de novo drug discovery approaches. Thus, we also discuss the different drug repurposing strategies available with a special emphasis in their applications to the identification of drug candidates targeting essential components of the thiol-polyamine metabolism of T. cruzi.

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Antibody structure–function relationships

Therapeutic Antibody Engineering ◽

10.1533/9781908818096.37 ◽

2012 ◽

pp. 37-595

Keyword(s):

Structure Function ◽

Antibody Structure

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