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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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Effects of TbKHC1 on T. brucei parasitaemia.WT and TbKHC1 KO parasitaemias were monitored in various mice and conditions: (A) WT mice treated with L-NAME or D-NAME; (B) iNOS KO and WT mice; (C,D) myeloid cell Arg1 KO mice (KO1 = LysMcreArg1-/lox; KO2 = Tie2creArg1-/lox) and controls (Arg1lox/lox); (E,F) WT mice treated with L-ornithine, D-mannose or D-galactose; (G) MMR KO and WT mice; (H) SIGN-R1 KO and control (Ctrl) mice. Data are means ± SEM of 4 individual mice of one representative from 3 independent experiments. * p<0.05 comparing D-NAME and L-NAME treated mice (A) or WT and iNOS KO mice (B) infected with WT parasites; ∇ p<0.05 comparing Arg1lox/lox and LysMcreArg1-/lox or Tie2creArg1-/lox mice infected with WT parasites; # p<0.05 comparing L-ornithine treated and non treated mice infected with TbKHC1 KO parasites; ¥ p<0.05 comparing D-mannose and D-galactose-treated mice infected with WT parasites; £ p<0.05 comparing SIGN-R1 KO and control mice infected with WT parasites.
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ppat-1003731-g005: Effects of TbKHC1 on T. brucei parasitaemia.WT and TbKHC1 KO parasitaemias were monitored in various mice and conditions: (A) WT mice treated with L-NAME or D-NAME; (B) iNOS KO and WT mice; (C,D) myeloid cell Arg1 KO mice (KO1 = LysMcreArg1-/lox; KO2 = Tie2creArg1-/lox) and controls (Arg1lox/lox); (E,F) WT mice treated with L-ornithine, D-mannose or D-galactose; (G) MMR KO and WT mice; (H) SIGN-R1 KO and control (Ctrl) mice. Data are means ± SEM of 4 individual mice of one representative from 3 independent experiments. * p<0.05 comparing D-NAME and L-NAME treated mice (A) or WT and iNOS KO mice (B) infected with WT parasites; ∇ p<0.05 comparing Arg1lox/lox and LysMcreArg1-/lox or Tie2creArg1-/lox mice infected with WT parasites; # p<0.05 comparing L-ornithine treated and non treated mice infected with TbKHC1 KO parasites; ¥ p<0.05 comparing D-mannose and D-galactose-treated mice infected with WT parasites; £ p<0.05 comparing SIGN-R1 KO and control mice infected with WT parasites.

Mentions: In TbKHC1 KO-infected mice, it is unlikely that the reduction of the first peak of parasitaemia resulted from increased NO production. Indeed, inhibition of NOS activity by N-(G)-nitro-L-arginine methyl ester (L-NAME) or absence of iNOS activity in iNOS KO mice did not affect TbKHC1 KO parasitaemia, while it strongly reduced WT parasitaemia (Fig. 5A,B). The lower parasitaemia in TbKHC1 KO-infected mice might rather result from reduced arginase activity, which would limit nutrient availability for the parasite. Indeed, this enzyme converts L-arginine to L-ornithine, a precursor of polyamines that are required for trypanosome growth [13]. Accordingly, in mice lacking arginase-1 in myeloid cells/macrophages following a cross between Arg1 loxP-targeted mice and LysMCre or Tie2Cre deleter mice [21], WT parasitaemia dropped to that of TbKHC1 KO parasitaemia (Fig. 5C,D). Moreover, treatment of mice with L-ornithine increased the cumulative parasite load to a greater extent in TbKHC1 KO- than in WT-infected mice (∼94% vs ∼43%, respectively; Fig. 5E). In addition, spermine levels tended to increase although without reaching statistical significance in spleen myeloid cells and blood from mice infected with WT but not TbKHC1 KO parasites (Fig. S4A in Text S1). Furthermore, an increase in L-ornithine production, coinciding with the consumption of L-arginine and the induction of N-acetylputrescine production, was observed in the supernatant of myeloid cells from non-infected mice activated in vitro with rTbKHC1 (Fig. S4B in Text S1).


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)

Effects of TbKHC1 on T. brucei parasitaemia.WT and TbKHC1 KO parasitaemias were monitored in various mice and conditions: (A) WT mice treated with L-NAME or D-NAME; (B) iNOS KO and WT mice; (C,D) myeloid cell Arg1 KO mice (KO1 = LysMcreArg1-/lox; KO2 = Tie2creArg1-/lox) and controls (Arg1lox/lox); (E,F) WT mice treated with L-ornithine, D-mannose or D-galactose; (G) MMR KO and WT mice; (H) SIGN-R1 KO and control (Ctrl) mice. Data are means ± SEM of 4 individual mice of one representative from 3 independent experiments. * p<0.05 comparing D-NAME and L-NAME treated mice (A) or WT and iNOS KO mice (B) infected with WT parasites; ∇ p<0.05 comparing Arg1lox/lox and LysMcreArg1-/lox or Tie2creArg1-/lox mice infected with WT parasites; # p<0.05 comparing L-ornithine treated and non treated mice infected with TbKHC1 KO parasites; ¥ p<0.05 comparing D-mannose and D-galactose-treated mice infected with WT parasites; £ p<0.05 comparing SIGN-R1 KO and control mice infected with WT parasites.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3814429&req=5

ppat-1003731-g005: Effects of TbKHC1 on T. brucei parasitaemia.WT and TbKHC1 KO parasitaemias were monitored in various mice and conditions: (A) WT mice treated with L-NAME or D-NAME; (B) iNOS KO and WT mice; (C,D) myeloid cell Arg1 KO mice (KO1 = LysMcreArg1-/lox; KO2 = Tie2creArg1-/lox) and controls (Arg1lox/lox); (E,F) WT mice treated with L-ornithine, D-mannose or D-galactose; (G) MMR KO and WT mice; (H) SIGN-R1 KO and control (Ctrl) mice. Data are means ± SEM of 4 individual mice of one representative from 3 independent experiments. * p<0.05 comparing D-NAME and L-NAME treated mice (A) or WT and iNOS KO mice (B) infected with WT parasites; ∇ p<0.05 comparing Arg1lox/lox and LysMcreArg1-/lox or Tie2creArg1-/lox mice infected with WT parasites; # p<0.05 comparing L-ornithine treated and non treated mice infected with TbKHC1 KO parasites; ¥ p<0.05 comparing D-mannose and D-galactose-treated mice infected with WT parasites; £ p<0.05 comparing SIGN-R1 KO and control mice infected with WT parasites.
Mentions: In TbKHC1 KO-infected mice, it is unlikely that the reduction of the first peak of parasitaemia resulted from increased NO production. Indeed, inhibition of NOS activity by N-(G)-nitro-L-arginine methyl ester (L-NAME) or absence of iNOS activity in iNOS KO mice did not affect TbKHC1 KO parasitaemia, while it strongly reduced WT parasitaemia (Fig. 5A,B). The lower parasitaemia in TbKHC1 KO-infected mice might rather result from reduced arginase activity, which would limit nutrient availability for the parasite. Indeed, this enzyme converts L-arginine to L-ornithine, a precursor of polyamines that are required for trypanosome growth [13]. Accordingly, in mice lacking arginase-1 in myeloid cells/macrophages following a cross between Arg1 loxP-targeted mice and LysMCre or Tie2Cre deleter mice [21], WT parasitaemia dropped to that of TbKHC1 KO parasitaemia (Fig. 5C,D). Moreover, treatment of mice with L-ornithine increased the cumulative parasite load to a greater extent in TbKHC1 KO- than in WT-infected mice (∼94% vs ∼43%, respectively; Fig. 5E). In addition, spermine levels tended to increase although without reaching statistical significance in spleen myeloid cells and blood from mice infected with WT but not TbKHC1 KO parasites (Fig. S4A in Text S1). Furthermore, an increase in L-ornithine production, coinciding with the consumption of L-arginine and the induction of N-acetylputrescine production, was observed in the supernatant of myeloid cells from non-infected mice activated in vitro with rTbKHC1 (Fig. S4B in Text S1).

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