Supplementary Material for: Rapamycin Treatment Reduces Acute Myocarditis Induced by <b><i>Trypanosoma cruzi</i></b> Infection

Chagas disease affects millions of people mainly in Latin America and is a protozoan illness caused by the parasite Trypanosoma cruzi. Chagasic cardiomyopathy is the leading cause of mortality of infected patients, due to compromised electrical and mechanical cardiac function induced by tissue remodeling, especially fibrosis, and lymphocytic infiltration. Some cellular biochemical pathways can be protective to the heart, and we tested if the in vivo activation of the autophagic machinery by rapamycin could reduce parasite-induced myocarditis. Regarding the expression of LC3, an autophagy marker, we observed its upregulation in the cardiac tissue of infected untreated mice. However, after rapamycin treatment, an autophagy inducer, infected mice showed reduced electrical cardiac dysfunctions, myocarditis, cardiac damage, and reduced production of pro-inflammatory cytokines by the heart. On the other hand, the parasite’s life cycle was not affected, and we observed no modulations in cardiac tissue or blood parasitemia. Our data indicate that, at least partially, autophagy induction controls inflammation in the heart¸ illustrating the complexity of the pathways that concur to the development of the infection.查加斯病（Chagas disease）主要在拉丁美洲影响数百万人群，是由克氏锥虫（Trypanosoma cruzi）引发的原生动物感染性疾病。查加斯心肌病（Chagasic cardiomyopathy）是感染者死亡的首要诱因，其发病机制为组织重塑（尤其是纤维化（fibrosis））与淋巴细胞浸润（lymphocytic infiltration）诱导的心脏电活动与机械功能受损。 部分细胞生化通路可对心脏发挥保护作用，本研究验证了在活体中通过自噬诱导剂雷帕霉素（rapamycin）激活自噬机制（autophagic machinery）是否能够减轻寄生虫诱导的心肌炎（myocarditis）。 针对自噬标记物LC3的表达水平，我们观察到未接受治疗的感染小鼠心脏组织中LC3呈现上调表达。经雷帕霉素处理后，感染小鼠的心脏电功能障碍、心肌炎及心脏损伤均得到缓解，同时心脏分泌的促炎细胞因子（pro-inflammatory cytokines）水平也显著降低。与之相反，寄生虫的生命周期未受影响，我们未观察到心脏组织或血液中的寄生虫血症（parasitemia）出现明显变化。 本研究数据表明，自噬诱导至少可在一定程度上抑制心脏炎症反应，这也揭示了参与感染进程的各类通路的复杂性。