Trypanosoma cruzi infection induces proliferation and impairs migration of a human breast cancer cell line.

Breast cancer is considered the type of cancer that most affects women in the world. The triple negative breast cancer is considered aggressive with poor prognosis. In the 1930s Russian researchers observed that T. cruzi has tropism for tumor cells. Since then, this research field has been subject of a numerous of researches. Here, we proposed to investigate the impact of T. cruzi infection on proliferation and migration of triple negative breast cancer cell line (MDA-MB-231). T. cruzi showed high invasion and multiplication rate in MDA-MB-231 cell line. The infection promoted the multiplication of MDA-MB-231 cell, continuous cell lysis throughout of days of in vitro infection and impaired MDA-MB-231 cell migration. Taken together, these results demonstrated the high susceptibility of MDA-MB-231 cell to T. cruzi and suggested that molecules from T. cruzi may impair host cell migration with potential use to avoid metastasis.

Ablation of the P21 Gene of Trypanosoma cruzi Provides Evidence of P21 as a Mediator in the Control of Epimastigote and Intracellular Amastigote Replication.

P21 is an immunomodulatory protein expressed throughout the life cycle of Trypanosoma cruzi, the etiologic agent of Chagas disease. In vitro and in vivo studies have shown that P21 plays an important role in the invasion of mammalian host cells and establishment of infection in a murine model. P21 functions as a signal transducer, triggering intracellular cascades in host cells and resulting in the remodeling of the actin cytoskeleton and parasite internalization. Furthermore, in vivo studies have shown that P21 inhibits angiogenesis, induces inflammation and fibrosis, and regulates intracellular amastigote replication. In this study, we used the CRISPR/Cas9 system for P21 gene knockout and investigated whether the ablation of P21 results in changes in the phenotypes associated with this protein. Ablation of P21 gene resulted in a lower growth rate of epimastigotes and delayed cell cycle progression, accompanied by accumulation of parasites in G1 phase. However, P21 knockout epimastigotes were viable and able to differentiate into metacyclic trypomastigotes, which are infective to mammalian cells. In comparison with wild-type parasites, P21 knockout cells showed a reduced cell invasion rate, demonstrating the role of this protein in host cell invasion. However, there was a higher number of intracellular amastigotes per cell, suggesting that P21 is a negative regulator of amastigote proliferation in mammalian cells. Here, for the first time, we demonstrated the direct correlation between P21 and the replication of intracellular amastigotes, which underlies the chronicity of T. cruzi infection.

Peroxisome Proliferator-Activated Receptor Alpha Mediates the Beneficial Effects of Atorvastatin in Experimental Colitis.

The current therapeutic options for Inflammatory Bowel Diseases (IBD) are limited. Even using common anti-inflammatory, immunosuppressive or biological therapies, many patients become unresponsive to the treatments, immunosuppressed or unable to restrain secondary infections. Statins are cholesterol-lowering drugs with non-canonical anti-inflammatory properties, whose underlying mechanisms of action still remain poorly understood. Here, we described that in vitro atorvastatin (ATO) treatment was not toxic to splenocytes, constrained cell proliferation and modulated IL-6 and IL-10 production in a dose-dependent manner. Mice exposed to dextran sulfate sodium (DSS) for colitis induction and treated with ATO shifted their immune response from Th17 towards Th2, improved the clinical and histological aspects of intestinal inflammation and reduced the number of circulating leukocytes. Both experimental and in silico analyses revealed that PPAR-α expression is reduced in experimental colitis, which was reversed by ATO treatment. While IBD patients also downregulate PPAR-α expression, the responsiveness to biological therapy relied on the restoration of PPAR-α levels. Indeed, the in vitro and in vivo effects induced by ATO treatment were abrogated in Ppara-/- mice or leukocytes. In conclusion, the beneficial effects of ATO in colitis are dependent on PPAR-α, which could also be a potential predictive biomarker of therapy responsiveness in IBD.

The Recombinant Form of Trypanosoma cruzi P21 Controls Infection by Modulating Host Immune Response.

Trypanosoma cruzi P21 protein (P21) is a putative secreted and immunomodulatory molecule with potent bioactive properties such as induction of phagocytosis and actin cytoskeleton polymerization. Despite the bioactive properties described so far, the action of P21 on parasite replication in muscle cell lineage or T. cruzi parasitism during acute experimental infection is unclear. We observed that recombinant P21 (rP21) decreased the multiplication of T. cruzi in C2C12 myoblasts, phenomenon associated with greater actin polymerization and IFN-γ and IL-4 higher expression. During experimental infection, lower cardiac nests, inflammatory infiltrate and fibrosis were observed in mice infected and treated with rP21. These results were correlated with large expression of IFN-γ counterbalanced by high levels of IL-10, which was consistent with the lower cardiac tissue injury found in these mice. We have also observed that upon stress, such as that induced by the presence of the IFN-γ cytokine, T. cruzi produced more P21. The effect of P21 in controlling the replication of T. cruzi, may indicate an evolutionary mechanism of survival developed by the parasite. Thus, when subjected to different stress conditions, the protozoan produces more P21, which induces T. cruzi latency in the host organism, enabling the protozoan to evade the host's immune system.

Human B cells infected by Trypanosoma cruzi undergo F-actin disruption and cell death via caspase-7 activation and cleavage of phospholipase Cgama1

B cells contribute to the immune system in many ways such as antigen presentation to CD4+ T cells, secretion of cytokines and lymphoid tissue organogenesis. Furthermore, they are the only cell type capable of producing immunoglobulins. B cells also account for critical aspects of the resistance against intracellular pathogens. Trypanosoma cruzi is an intracellular parasite that sabotages humoral response by depletion of immature B cells. Polyclonal activation and secretion of non-specific antibodies are also other mechanisms used by T cruzi to evade and subvert the mammalian host immune system, leading to increased parasitemia and susceptibility to Chagas’ disease. It remained unclear whether B cell depletion occurs due to direct contact with T. cruzi or results from a global increase in inflammation. Unlike previous reports, we demonstrated in this study that T. cruzi infects human B cells, resulting in parasite-induced activation of caspase-7 followed by proteolytic cleavage of phospholipase Cgama1 and cell death. These data contribute to explain the mechanisms ruling B-cell depletion and evasion of the immune response by T. cruzi.

Human B cells infected by Trypanosoma cruzi undergo F-actin disruption and cell death via caspase-7 activation and cleavage of phospholipase Cgama1

B cells contribute to the immune system in many ways such as antigen presentation to CD4+ T cells, secretion of cytokines and lymphoid tissue organogenesis. Furthermore, they are the only cell type capable of producing immunoglobulins. B cells also account for critical aspects of the resistance against intracellular pathogens. Trypanosoma cruzi is an intracellular parasite that sabotages humoral response by depletion of immature B cells. Polyclonal activation and secretion of non-specific antibodies are also other mechanisms used by T cruzi to evade and subvert the mammalian host immune system, leading to increased parasitemia and susceptibility to Chagas’ disease. It remained unclear whether B cell depletion occurs due to direct contact with T. cruzi or results from a global increase in inflammation. Unlike previous reports, we demonstrated in this study that T. cruzi infects human B cells, resulting in parasite-induced activation of caspase-7 followed by proteolytic cleavage of phospholipase Cgama1 and cell death. These data contribute to explain the mechanisms ruling B-cell depletion and evasion of the immune response by T. cruzi.