Killy Barbara, Bodendorfer Barbara, Mages Jörg, Ritter Kristina, Schreiber Jonathan, Hölscher Christoph, Pracht Katharina, Ekici Arif, Jäck Hans-Martin, Lang Roland
Institute of Clinical Microbiology, Immunology and Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
It's Biology, Madrid, Spain.
Life Sci Alliance. 2021 Mar 26;4(6). doi: 10.26508/lsa.202000810. Print 2021 Jun.
The mycobacterial cell wall glycolipid trehalose-6,6-dimycolate (TDM) activates macrophages through the C-type lectin receptor MINCLE. Regulation of innate immune cells relies on miRNAs, which may be exploited by mycobacteria to survive and replicate in macrophages. Here, we have used macrophages deficient in the microprocessor component DGCR8 to investigate the impact of miRNA on the response to TDM. Deletion of DGCR8 in bone marrow progenitors reduced macrophage yield, but did not block macrophage differentiation. DGCR8-deficient macrophages showed reduced constitutive and TDM-inducible miRNA expression. RNAseq analysis revealed that they accumulated primary miRNA transcripts and displayed a modest type I IFN signature at baseline. Stimulation with TDM in the absence of DGCR8 induced overshooting expression of IFNβ and IFN-induced genes, which was blocked by antibodies to type I IFN. In contrast, signaling and transcriptional responses to recombinant IFNβ were unaltered. Infection with live Bacille Calmette-Guerin replicated the enhanced IFN response. Together, our results reveal an essential role for DGCR8 in curbing IFNβ expression macrophage reprogramming by mycobacteria.
分枝杆菌细胞壁糖脂海藻糖-6,6-二霉菌酸酯（TDM）通过C型凝集素受体MINCLE激活巨噬细胞。先天性免疫细胞的调节依赖于微小RNA（miRNA），分枝杆菌可能利用这些miRNA在巨噬细胞中存活和复制。在此，我们利用微处理器组件DGCR8缺陷的巨噬细胞来研究miRNA对TDM反应的影响。骨髓祖细胞中DGCR8的缺失降低了巨噬细胞产量，但并未阻断巨噬细胞分化。DGCR8缺陷的巨噬细胞显示出组成型和TDM诱导型miRNA表达降低。RNA测序分析表明，它们积累了初级miRNA转录本，并在基线时表现出适度的I型干扰素特征。在缺乏DGCR8的情况下用TDM刺激诱导IFNβ和IFN诱导基因的过度表达，这被I型干扰素抗体所阻断。相反，对重组IFNβ的信号传导和转录反应未改变。用活的卡介苗感染重现了增强的IFN反应。总之，我们的结果揭示了DGCR8在抑制分枝杆菌诱导的巨噬细胞重编程中IFNβ表达方面的重要作用。
