The mechanism whereby Entamoeba histolytica (Eh) binding with macrophages at the intercellular junction triggers aggressive pro-inflammatory responses in disease pathogenesis is not well understood. The host intracellular protein degradation process autophagy and its regulatory proteins are involved in maintenance of cellular homeostasis and excessive inflammatory responses. In this study we unraveled how Eh hijacks the autophagy process in macrophages to dysregulate pro-inflammatory responses. Direct contact of live Eh with macrophages activated caspase-6 that induced rapid proteolytic degradation of the autophagy ATG16L1 protein complex independent of NLRP3 inflammasome and caspase-3/8 activation. Crohn’s disease susceptible ATG16L1 T300A variant was highly susceptible to Eh-mediated degradation that augmented pro-inflammatory cytokines in mice. Quantitative proteomics revealed downregulation of autophagy and vesicle-mediated transport and upregulation of cysteine-type endopeptidase pathways in response to Eh. We conclude during Eh-macrophage outside-in signaling, ATG16L1 protein complex plays an overlooked regulatory role in shaping the pro-inflammatory landscape in amebiasis.

溶组织内阿米巴( Eh )在细胞间连接处与巨噬细胞结合引发疾病发病机制中侵袭性促炎反应的机制尚不清楚。宿主细胞内蛋白质降解过程自噬及其调节蛋白参与维持细胞稳态和过度炎症反应。在这项研究中，我们揭示了Eh如何劫持巨噬细胞中的自噬过程以失调促炎反应。直播Eh的直接联系方式巨噬细胞激活的 caspase-6 诱导自噬 ATG16L1 蛋白复合物的快速蛋白水解降解，与 NLRP3 炎性体和 caspase-3/8 激活无关。克罗恩病易感 ATG16L1 T300A 变体对Eh介导的降解高度敏感，这种降解增强了小鼠的促炎细胞因子。定量蛋白质组学揭示了响应于Eh的自噬和囊泡介导的转运下调以及半胱氨酸型内肽酶途径的上调。我们得出结论，在Eh-巨噬细胞由外向内信号传导过程中，ATG16L1 蛋白复合物在塑造阿米巴病的促炎景观方面起着被忽视的调节作用。