Mouse Macrophage Galactose-type Lectin (mMGL) is Critical for Host Resistance against Trypanosoma cruzi Infection (original) (raw)
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Cells, 2020
Macrophage galactose-C type lectin (MGL)1 receptor is involved in the recognition of Trypanosoma cruzi (T. cruzi) parasites and is important for the modulation of the innate and adaptive immune responses. However, the mechanism by which MGL1 promotes resistance to T. cruzi remains unclear. Here, we show that MGL1 knockout macrophages (MGL1−/− Mφ) infected in vitro with T. cruzi were heavily parasitized and showed decreased levels of reactive oxygen species (ROS), nitric oxide (NO), IL-12 and TNF-α compared to wild-type macrophages (WT Mφ). MGL1−/− Mφ stimulated in vitro with T. cruzi antigen (TcAg) showed low expression of TLR-2, TLR-4 and MHC-II, which resulted in deficient splenic cell activation compared with similar co-cultured WT Mφ. Importantly, the activation of p-ERK1/2, p-c-Jun and p-NF-κB p65 were significantly reduced in MGL1−/− Mφ exposed to TcAg. Similarly, procaspase 1, caspase 1 and NLRP3 inflammasome also displayed a reduced expression that was associated with low IL-β production. Our data reveal a previously unappreciated role for MGL1 in Mφ activation through the modulation of ERK1/2, c-Jun, NF-κB and NLRP3 signaling pathways, and to the development of protective innate immunity against experimental T. cruzi infection.
International Journal for Parasitology, 2007
Innate and adaptive immunity collaborate in the protection of intracellular pathogens including Trypanosoma cruzi infection. However, the parasite molecules that regulate the host immune response have not been fully identified. We previously demonstrated that the immunisation of C57BL/6 mice with cruzipain, an immunogenic T. cruzi glycoprotein, induced a strong specific T-cell response. In this study, we demonstrated that active immunisation with cruzipain was able to stimulate nitric oxide (NO) production by splenocytes. Immune cells also showed increased inducible nitric oxide synthase protein and mRNA expression. Spleen adherent cells secreted high levels of IFN-c and IL-12. Microbicidal activity in vitro was mainly mediated by reactive nitrogen intermediaries and IFN-c, as demonstrated by the inhibitory effects of NO synthase inhibitor or by IFN-c neutralisation. Specific T-cells were essential for NO, IFN-c and TNF-a production. Furthermore, we reported that cruzipain enhanced CD80 and major histocompatibility complex-II molecule surface expression on F4/80+ spleen cells. Interestingly, we also showed that cruzipain up-regulated toll like receptor-2 expression, not only in F4/80+ but also in total spleen cells which may be involved in the effector immune response. Our findings suggest that a single parasite antigen such as cruzipain, through adaptive immune cells and cytokines, can modulate the macrophage response not only as antigen presenting cells, but also as effector cells displaying enhanced microbicidal activity with reactive nitrogen intermediary participation. This may represent a mechanism that contributes to the immunoregulatory process during Chagas disease. Ó
The Journal of Immunology, 2004
TLRs function as pattern recognition receptors in mammals and play an essential role in the recognition of microbial components. We found that the injection of glycoinositolphospholipids (GIPLs) from Trypanosoma cruzi into the peritoneal cavity of mice induced neutrophil recruitment in a TLR4-dependent manner: the injection of GIPL in the TLR4-deficient strain of mice (C57BL/ 10ScCr) caused no inflammatory response. In contrast, in TLR2 knockout mice, neutrophil chemoattraction did not differ significantly from that seen in wild-type controls. GIPL-induced neutrophil attraction and MIP-2 production were also severely affected in TLR4-mutant C3H/HeJ mice.
Mediators of Inflammation, 2014
Chagas disease, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), is characterized by immunopathology driven by IFN-secreting Th1-like T cells. T. cruzi has a thick coat of mucin-like glycoproteins covering its surface, which plays an important role in parasite invasion and host immunomodulation. It has been extensively described that T. cruzi or its products-like GPI anchors isolated from GPI-anchored mucins from the trypomastigote life cycle stage (tGPI-mucins)-are potent inducers of proinflammatory responses (i.e., cytokines and NO production) by IFN-primed murine macrophages. However, little is known about whether T. cruzi or GPI-mucins exert a similar action in human cells. We therefore decided to further investigate the in vitro cytokine production profile from human mononuclear cells from uninfected donors exposed to T. cruzi as well as tGPI-mucins. We observed that both living T. cruzi trypomastigotes and tGPI-mucins are potent inducers of IL-12 by human peripheral blood monocytes and this effect depends on CD40-CD40L interaction and IFN-. Our findings suggest that the polarized T1-type cytokine profile seen in T. cruzi infected patients might be a long-term effect of IL-12 production induced by lifelong exposure to T. cruzi tGPI-mucins.
The Journal of …, 2004
TLRs function as pattern recognition receptors in mammals and play an essential role in the recognition of microbial components. We found that the injection of glycoinositolphospholipids (GIPLs) from Trypanosoma cruzi into the peritoneal cavity of mice induced neutrophil recruitment in a TLR4-dependent manner: the injection of GIPL in the TLR4-deficient strain of mice (C57BL/ 10ScCr) caused no inflammatory response. In contrast, in TLR2 knockout mice, neutrophil chemoattraction did not differ significantly from that seen in wild-type controls. GIPL-induced neutrophil attraction and MIP-2 production were also severely affected in TLR4-mutant C3H/HeJ mice. The role of TLR4 was confirmed in vitro by testing genetically engineered mutants derived from TLR2-deficient Chinese hamster ovary (CHO)-K1 fibroblasts that were transfected with CD14 (CHO/CD14). Wildtype CHO/CD14 cells express the hamster TLR4 molecule and the mutant line, in addition, expresses a nonfunctional form of MD-2. In comparison to wild-type cells, mutant CHO/CD14 cells failed to respond to GIPLs, indicating a necessity for a functional TLR4/MD-2 complex in GIPL-induced NF-B activation. Finally, we found that TLR4-mutant mice were hypersusceptible to T. cruzi infection, as evidenced by a higher parasitemia and earlier mortality. These results demonstrate that natural resistance to T. cruzi is TLR4 dependent, most likely due to TLR4 recognition of their GIPLs.
The Journal of Immunology, 2002
Glycosylphosphatidylinositol-anchored mucin-like glycoproteins from Trypanosoma cruzi trypomastigotes (tGPI-mucins) activate macrophages in vitro to produce proinflammatory cytokines, chemokines, and nitric oxide. These effects of tGPI-mucins may be important in the ensuing immune response to T. cruzi. Here, we have sought evidence for a role of tGPI-mucins in mediating leukocyte recruitment in vivo. tGPI-mucins are highly effective in promoting cell recruitment in the pleural cavity of mice primed with IFN-␥-inducing agents but not in naïve mice. Maximal recruitment was observed at a dose between 250 and 1250 ng tGPI-mucins. There was a significant elevation in the levels of MCP-1 in the pleural cavity of primed animals injected with tGPI-mucins, and in vivo neutralization of MCP-1 abolished leukocyte recruitment. Pretreatment with anti-MIP-1␣ or anti-RANTES had no effect on the recruitment induced by tGPI-mucins. MCP-1 immunoreactivity was detected in pleural macrophages, and macrophages produced MCP-1 in vitro, especially after priming with IFN-␥. Finally, tGPI-mucins induced significant leukocyte recruitment in primed C3H/