PDF(Pubmed)
Abstract：
Anti-bacterial autophagy, also known as xenophagy, is a crucial innate immune process that helps maintain cellular homeostasis by targeting invading microbes. This defense pathway is widely studied in the context of infections with mycobacteria, the causative agents of human tuberculosis and tuberculosis-like disease in animal models. Our previous work in a zebrafish tuberculosis model showed that host defense against Mycobacterium marinum (Mm) is impaired by deficiencies in xenophagy receptors, optineurin (Optn) or sequestome 1 (p62), and Damage-regulated autophagy modulator 1 (Dram1). However, the interdependency of these receptors and their interaction with Dram1 remained unknown. In the present study, we used single and double knockout zebrafish lines in combination with overexpression experiments. We show that Optn and p62 can compensate for the loss of each other\'s function, as their overexpression restores the infection susceptibility of the mutant phenotypes. Similarly, Dram1 can compensate for deficiencies in Optn and p62, and, vice versa, Optn and p62 compensate for the loss of Dram1, indicating that these xenophagy receptors and Dram1 do not rely on each other for host defense against Mm. In agreement, Dram1 overexpression in optn/p62 double mutants restored the interaction of autophagosome marker Lc3 with Mm. Finally, optn/p62 double mutants displayed more severe infection susceptibility than the single mutants. Taken together, these results suggest that Optn and p62 do not function downstream of each other in the anti-mycobacterial xenophagy pathway, and that the Dram1-mediated defense against Mm infection does not rely on specific xenophagy receptors.
摘要：
抗细菌自噬，也被称为异种吞噬，是一个至关重要的先天免疫过程，通过靶向入侵的微生物来帮助维持细胞内稳态。这种防御途径在分枝杆菌感染的背景下被广泛研究，动物模型中人类结核病和结核病样疾病的病原体。我们以前在斑马鱼结核病模型中的工作表明，宿主对分枝杆菌（Mm）的防御受到异种吞噬受体缺陷的损害，视神经磷酸酶（Optn）或隔离组1（p62），和损伤调节的自噬调节剂1（Dram1）。然而,这些受体的相互依赖性及其与Dram1的相互作用仍然未知。在本研究中,我们使用单和双敲除斑马鱼品系与过表达实验相结合。我们证明了Optn和p62可以补偿彼此函数的损失，因为它们的过表达恢复了突变表型的感染易感性。同样，Dram1可以弥补Optn和p62的不足，反之亦然,Optn和p62补偿了Dram1的损失，表明这些异种吞噬受体和Dram1并不彼此依赖宿主防御Mm。在协议中,optn/p62双突变体中的Dram1过表达恢复了自噬小体标记Lc3与Mm的相互作用。最后,optn/p62双突变体比单个突变体显示出更严重的感染易感性。一起来看,这些结果表明，Optn和p62在抗分枝杆菌异种吞噬途径中不在彼此的下游起作用，并且Dram1介导的针对Mm感染的防御不依赖于特定的异种吞噬受体。
