Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
The Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02139, USA.
Nat Microbiol. 2017 Jun 26;2:17099. doi: 10.1038/nmicrobiol.2017.99.
The immunomodulatory surface molecules of commensal and pathogenic bacteria are critical to microorganisms' survival and the host's response. Recent studies have highlighted the unique and important responses elicited by commensal-derived surface macromolecules. However, the technology available to track these molecules in host cells and tissues remains primitive. We report, here, an interdisciplinary approach that uses metabolic labelling combined with bioorthogonal click chemistry (that is, reactions performed in living organisms) to specifically tag up to three prominent surface immunomodulatory macromolecules-peptidoglycan, lipopolysaccharide and capsular polysaccharide-either simultaneously or individually in live anaerobic commensal bacteria. Importantly, the peptidoglycan labelling enables, for the first time, the specific labelling of live endogenous, anaerobic bacteria within the mammalian host. This approach has allowed us to image and track the path of labelled surface molecules from live, luminal bacteria into specific intestinal immune cells in the living murine host during health and disease. The chemical labelling of three specific macromolecules within a live organism offers the potential for in-depth visualization of host-pathogen interactions.
共生菌和病原菌的免疫调节表面分子对微生物的生存和宿主的反应至关重要。最近的研究强调了共生菌来源的表面大分子所引起的独特而重要的反应。然而，用于在宿主细胞和组织中追踪这些分子的技术仍然很原始。我们在这里报告了一种跨学科的方法，该方法使用代谢标记结合生物正交点击化学（即在活生物体中进行的反应），可以同时或单独地对多达三种突出的表面免疫调节大分子（肽聚糖、脂多糖和荚膜多糖）进行特异性标记，活的厌氧共生菌。重要的是，肽聚糖标记首次使内源性、活的、厌氧细菌在哺乳动物宿主内的特异性标记成为可能。这种方法使我们能够在健康和疾病状态下，对活的、腔道内的细菌中的标记表面分子进行成像和追踪，使其进入特定的肠道免疫细胞。在活生物体中对三种特定大分子进行化学标记为深入可视化宿主-病原体相互作用提供了可能。
