RESUMO
Chagas disease is caused by infection with the protozoan Trypanosoma cruzi. CD8 T-lymphocytes help to control infection, but apoptosis of CD8 T cells disrupts immunity and efferocytosis can enhance parasite infection within macrophages. Here, we investigate how apoptosis of activated CD8 T cells affects M1 and M2 macrophage phenotypes. First, we found that CD8 T-lymphocytes and inflammatory monocytes/macrophages infiltrate peritoneum during acute T. cruzi infection. We show that treatment with anti-Fas ligand (FasL) prevents lymphocyte apoptosis, upregulates type-1 responses to parasite antigens, and reduces infection in macrophages cocultured with activated CD8 T cells. Anti-FasL skews mixed M1/M2 macrophage profiles into polarized M1 phenotype, both in vitro and following injection in infected mice. Moreover, inhibition of T-cell apoptosis induces a broad reprogramming of cytokine responses and improves macrophage-mediated immunity to T. cruzi. The results indicate that disposal of apoptotic CD8 T cells increases M2-macrophage differentiation and contributes to parasite persistence.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/imunologia , Proteína Ligante Fas/antagonistas & inibidores , Interações Hospedeiro-Parasita , Imunidade Celular/efeitos dos fármacos , Macrófagos/imunologia , Animais , Anticorpos Neutralizantes/farmacologia , Apoptose/efeitos dos fármacos , Assialoglicoproteínas/genética , Assialoglicoproteínas/imunologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/parasitologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/parasitologia , Comunicação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Doença de Chagas/tratamento farmacológico , Doença de Chagas/genética , Doença de Chagas/parasitologia , Técnicas de Cocultura , Proteína Ligante Fas/genética , Proteína Ligante Fas/imunologia , Regulação da Expressão Gênica , Subunidade p35 da Interleucina-12/genética , Subunidade p35 da Interleucina-12/imunologia , Lectinas Tipo C/genética , Lectinas Tipo C/imunologia , Ativação Linfocitária , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Fenótipo , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/imunologiaRESUMO
The pentacyclic triterpene α,ß-amyrin has been previously reported as an effective compound in the treatment of several inflammatory conditions. Recent evidence indicates that α,ß-amyrin displayed its effects through interaction with the cannabinoid pathway. We assessed the anti-inflammatory effects of the α,ß-amyrin in the dextran sulfate sodium (DSS)-induced colitis in mice and investigated whether its effects were associated with the interaction with the cannabinoid system. Our results showed that the oral preventive or therapeutic treatment with α,ß-amyrin significantly reduced disease activity, body weight loss, colonic damage, as well as colonic myeloperoxidase and N-acetylglucosaminidase activities. Moreover, α,ß-amyrin decreases the colonic pro-inflammatory mediators tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and keratinocyte-derived chemokine (CXCL1/KC), while up-regulating the IL-4 levels. Additionally, we also observed that the α,ß-amyrin caused a significant reduction of the adhesion molecules mRNA expression for intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), platelet cell adhesion molecule 1 (PCAM-1), ß(2)-integrin and protein expression for proliferation marker Ki67, the macrophage molecule CD68 and for adhesion molecule P-selectin. Interestingly, our results also showed that the cannabinoid receptor 1 (CB(1)), but not CB(2), pharmacological blockade significantly reversed the beneficial effects of α,ß-amyrin in DSS-induced colitis. Besides, our data demonstrated that mRNA expression for both the endocannabinoid hydrolase monoglyceride lipase 1 (MGL1) and fatty acid amide hydrolase (FAAH) were significantly reduced in the colon of α,ß-amyrin-treated mice. Altogether, these results suggest that the α,ß-amyrin might possess potential therapeutic interest for the treatment of IBD, and also provide new insights for the underlying mechanisms.