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A Trypanosoma brucei kinesin heavy chain promotes parasite growth by triggering host arginase activity.

De Muylder G, Daulouède S, Lecordier L, Uzureau P, Morias Y, Van Den Abbeele J, Caljon G, Hérin M, Holzmuller P, Semballa S, Courtois P, Vanhamme L, Stijlemans B, De Baetselier P, Barrett MP, Barlow JL, McKenzie AN, Barron L, Wynn TA, Beschin A, Vincendeau P, Pays E - PLoS Pathog. (2013)

Bottom Line: By screening a cDNA library of T. brucei with an antibody neutralizing the arginase-inducing activity of parasite released factors, we identified a Kinesin Heavy Chain isoform, termed TbKHC1, as responsible for this effect.This TbKHC1 activity was IL-4Rα-independent and did not mirror M2 activation of myeloid cells.By treating infected mice with ornithine or with NO synthase inhibitor, we observed that during the first wave of parasitaemia the parasite growth-promoting effect of TbKHC1-mediated arginase activation resulted more from increased polyamine production than from reduction of NO synthesis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles (ULB), Gosselies, Belgium.

ABSTRACT

Background: In order to promote infection, the blood-borne parasite Trypanosoma brucei releases factors that upregulate arginase expression and activity in myeloid cells.

Methodology/principal findings: By screening a cDNA library of T. brucei with an antibody neutralizing the arginase-inducing activity of parasite released factors, we identified a Kinesin Heavy Chain isoform, termed TbKHC1, as responsible for this effect. Following interaction with mouse myeloid cells, natural or recombinant TbKHC1 triggered SIGN-R1 receptor-dependent induction of IL-10 production, resulting in arginase-1 activation concomitant with reduction of nitric oxide (NO) synthase activity. This TbKHC1 activity was IL-4Rα-independent and did not mirror M2 activation of myeloid cells. As compared to wild-type T. brucei, infection by TbKHC1 KO parasites was characterized by strongly reduced parasitaemia and prolonged host survival time. By treating infected mice with ornithine or with NO synthase inhibitor, we observed that during the first wave of parasitaemia the parasite growth-promoting effect of TbKHC1-mediated arginase activation resulted more from increased polyamine production than from reduction of NO synthesis. In late stage infection, TbKHC1-mediated reduction of NO synthesis appeared to contribute to liver damage linked to shortening of host survival time.

Conclusion: A kinesin heavy chain released by T. brucei induces IL-10 and arginase-1 through SIGN-R1 signaling in myeloid cells, which promotes early trypanosome growth and favors parasite settlement in the host. Moreover, in the late stage of infection, the inhibition of NO synthesis by TbKHC1 contributes to liver pathogenicity.

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Induction of myeloid cell arginase activity by T. brucei PRF.Arginase activity was determined in myeloid cells from non-infected mice incubated with (A) WT parasites separated or not by an insert, or WT parasite-released factors (PRF), (B) PRF from WT parasites in presence of indicated antibodies and (C) PRF from WT or TbKHC1 KO parasites, or material purified on anti-PRF antibody affinity column, in presence of indicated antibodies. Heat treatment was at 45°C for 30 min. Data are means ± SEM of 3–4 individual mice of one representative from 3 independent experiments (A, B), or of triplicate cultures of one representative from 2 independent experiments (C). * p<0.05 compared to non-stimulated (-) cells.
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ppat-1003731-g001: Induction of myeloid cell arginase activity by T. brucei PRF.Arginase activity was determined in myeloid cells from non-infected mice incubated with (A) WT parasites separated or not by an insert, or WT parasite-released factors (PRF), (B) PRF from WT parasites in presence of indicated antibodies and (C) PRF from WT or TbKHC1 KO parasites, or material purified on anti-PRF antibody affinity column, in presence of indicated antibodies. Heat treatment was at 45°C for 30 min. Data are means ± SEM of 3–4 individual mice of one representative from 3 independent experiments (A, B), or of triplicate cultures of one representative from 2 independent experiments (C). * p<0.05 compared to non-stimulated (-) cells.

Mentions: T. brucei parasites were found to induce arginase activity in myeloid cells from non-infected mice (Fig. 1A). This induction was maintained when myeloid cells and trypanosomes were separated by a cell-retaining insert, indicating that soluble components from trypanosomes were involved (Fig. 1A). Parasite-released factors (PRF) were prepared under conditions leading to no detectable trypanosome death. PRF induced arginase activity, and this effect was abolished by heat-treatment (Fig. 1A). Monoclonal antibodies raised against T. brucei PRF (2C12) inhibited arginase activity induced by PRF, whereas other antibodies from the same hybridoma fusion (2A3, 2C6, 4B5) or of irrelevant specificity (5F6, 4J5) had no effect (Fig. 1B). The PRF fraction eluted after binding to a 2C12 antibody-based affinity column retained full arginase-inducing activity, confirming that this activity was directly targeted by 2C12 (Fig. 1C).


A Trypanosoma brucei kinesin heavy chain promotes parasite growth by triggering host arginase activity.

De Muylder G, Daulouède S, Lecordier L, Uzureau P, Morias Y, Van Den Abbeele J, Caljon G, Hérin M, Holzmuller P, Semballa S, Courtois P, Vanhamme L, Stijlemans B, De Baetselier P, Barrett MP, Barlow JL, McKenzie AN, Barron L, Wynn TA, Beschin A, Vincendeau P, Pays E - PLoS Pathog. (2013)

Induction of myeloid cell arginase activity by T. brucei PRF.Arginase activity was determined in myeloid cells from non-infected mice incubated with (A) WT parasites separated or not by an insert, or WT parasite-released factors (PRF), (B) PRF from WT parasites in presence of indicated antibodies and (C) PRF from WT or TbKHC1 KO parasites, or material purified on anti-PRF antibody affinity column, in presence of indicated antibodies. Heat treatment was at 45°C for 30 min. Data are means ± SEM of 3–4 individual mice of one representative from 3 independent experiments (A, B), or of triplicate cultures of one representative from 2 independent experiments (C). * p<0.05 compared to non-stimulated (-) cells.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814429&req=5

ppat-1003731-g001: Induction of myeloid cell arginase activity by T. brucei PRF.Arginase activity was determined in myeloid cells from non-infected mice incubated with (A) WT parasites separated or not by an insert, or WT parasite-released factors (PRF), (B) PRF from WT parasites in presence of indicated antibodies and (C) PRF from WT or TbKHC1 KO parasites, or material purified on anti-PRF antibody affinity column, in presence of indicated antibodies. Heat treatment was at 45°C for 30 min. Data are means ± SEM of 3–4 individual mice of one representative from 3 independent experiments (A, B), or of triplicate cultures of one representative from 2 independent experiments (C). * p<0.05 compared to non-stimulated (-) cells.
Mentions: T. brucei parasites were found to induce arginase activity in myeloid cells from non-infected mice (Fig. 1A). This induction was maintained when myeloid cells and trypanosomes were separated by a cell-retaining insert, indicating that soluble components from trypanosomes were involved (Fig. 1A). Parasite-released factors (PRF) were prepared under conditions leading to no detectable trypanosome death. PRF induced arginase activity, and this effect was abolished by heat-treatment (Fig. 1A). Monoclonal antibodies raised against T. brucei PRF (2C12) inhibited arginase activity induced by PRF, whereas other antibodies from the same hybridoma fusion (2A3, 2C6, 4B5) or of irrelevant specificity (5F6, 4J5) had no effect (Fig. 1B). The PRF fraction eluted after binding to a 2C12 antibody-based affinity column retained full arginase-inducing activity, confirming that this activity was directly targeted by 2C12 (Fig. 1C).

Bottom Line: By screening a cDNA library of T. brucei with an antibody neutralizing the arginase-inducing activity of parasite released factors, we identified a Kinesin Heavy Chain isoform, termed TbKHC1, as responsible for this effect.This TbKHC1 activity was IL-4Rα-independent and did not mirror M2 activation of myeloid cells.By treating infected mice with ornithine or with NO synthase inhibitor, we observed that during the first wave of parasitaemia the parasite growth-promoting effect of TbKHC1-mediated arginase activation resulted more from increased polyamine production than from reduction of NO synthesis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles (ULB), Gosselies, Belgium.

ABSTRACT

Background: In order to promote infection, the blood-borne parasite Trypanosoma brucei releases factors that upregulate arginase expression and activity in myeloid cells.

Methodology/principal findings: By screening a cDNA library of T. brucei with an antibody neutralizing the arginase-inducing activity of parasite released factors, we identified a Kinesin Heavy Chain isoform, termed TbKHC1, as responsible for this effect. Following interaction with mouse myeloid cells, natural or recombinant TbKHC1 triggered SIGN-R1 receptor-dependent induction of IL-10 production, resulting in arginase-1 activation concomitant with reduction of nitric oxide (NO) synthase activity. This TbKHC1 activity was IL-4Rα-independent and did not mirror M2 activation of myeloid cells. As compared to wild-type T. brucei, infection by TbKHC1 KO parasites was characterized by strongly reduced parasitaemia and prolonged host survival time. By treating infected mice with ornithine or with NO synthase inhibitor, we observed that during the first wave of parasitaemia the parasite growth-promoting effect of TbKHC1-mediated arginase activation resulted more from increased polyamine production than from reduction of NO synthesis. In late stage infection, TbKHC1-mediated reduction of NO synthesis appeared to contribute to liver damage linked to shortening of host survival time.

Conclusion: A kinesin heavy chain released by T. brucei induces IL-10 and arginase-1 through SIGN-R1 signaling in myeloid cells, which promotes early trypanosome growth and favors parasite settlement in the host. Moreover, in the late stage of infection, the inhibition of NO synthesis by TbKHC1 contributes to liver pathogenicity.

Show MeSH
Related in: MedlinePlus