Fu Kailai, Cui Jiaqi, Li Yao, Zhang Yuhan, Wang Yang, Wu Jiaoling, Chen Xinru, Xue Feng, Ren Jianluan, Dai Jianjun, Tang Fang
Key Laboratory of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China.
School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, China.
J Virol. 2025 Feb 25;99(2):e0178924. doi: 10.1128/jvi.01789-24. Epub 2024 Dec 26.
Phages, as antagonists of bacteria, hold significant promise for combating drug-resistant bacterial infections. Their host specificity allows phages to target pathogenic bacteria without disrupting the gut microbiota, offering distinct advantages in the prevention and control of intestinal pathogens. The interaction between the phage and the gut plays a crucial role in the efficacy of phage-mediated bacterial killing. However, the mechanisms underlying these interactions remain poorly understood. In this study, we demonstrate that the clinically isolated T4-like phage, ΦPNJ-9, effectively adheres to the intestinal mucosa . This adhesion is mediated by the phage's Hoc protein, which interacts with MUC2 in the mucus. The Hoc protein of ΦPNJ-9 represents a variant, consisting of only three domains and lacking Domain 3, in contrast to phage T4. The key interacting sites on ΦPNJ-9 Hoc are amino acids S183, L184, and T185 within Domain 2. Displaying Domain 2 of ΦPNJ-9 Hoc on the surface of M13 phage significantly enhances its adhesion to the intestinal mucosa. Additionally, we identify fucose residues in MUC2 as the critical binding sites for the phage. Through this adhesion, the phage occupies the intestinal niche, thereby protecting the mucosal layer from pathogenic infections. Our findings highlight the role of Hoc proteins in phage adhesion to intestinal mucus and the variation in binding sites, providing key insights for phage-based strategies aimed at preventing and controlling intestinal pathogens.IMPORTANCEThe rise in antibiotic-resistant pathogenic bacteria has sparked renewed interest in phage therapy as a promising alternative, particularly for targeting intestinal pathogens due to phage's host specificity. However, clinical applications have revealed that many phages are ineffective in eliminating bacteria within the gut, primarily due to the complex interactions between the phage and the gut environment. However, the mechanisms underlying these interactions remain poorly understood. Our previous study demonstrated that a T4-like phage adheres to the intestinal mucosa through the interaction between its Hoc protein and MUC2 in the mucus. Whether this model is widespread among T4-like phages remains unknown. Here, we characterize a variant Hoc protein from a T4-like phage, and identify new binding sites within this protein. Our findings suggest that the interaction between Hoc and MUC2 is likely common, but the critical binding sites vary depending on the specific phage.
噬菌体作为细菌的拮抗剂，在对抗耐药性细菌感染方面具有巨大潜力。它们的宿主特异性使噬菌体能够靶向病原菌而不破坏肠道微生物群，在预防和控制肠道病原体方面具有独特优势。噬菌体与肠道之间的相互作用在噬菌体介导的细菌杀灭效果中起着关键作用。然而，这些相互作用背后的机制仍知之甚少。在本研究中，我们证明临床分离的T4样噬菌体ΦPNJ-9能有效黏附于肠黏膜。这种黏附由噬菌体的Hoc蛋白介导，该蛋白与黏液中的MUC2相互作用。与噬菌体T4相比，ΦPNJ-9的Hoc蛋白是一种变体，仅由三个结构域组成且缺少结构域3。ΦPNJ-9 Hoc上的关键相互作用位点是结构域2内的氨基酸S183、L184和T185。在M13噬菌体表面展示ΦPNJ-9 Hoc的结构域2可显著增强其对肠黏膜的黏附。此外，我们确定MUC2中的岩藻糖残基是噬菌体的关键结合位点。通过这种黏附，噬菌体占据肠道生态位，从而保护黏膜层免受病原体感染。我们的研究结果突出了Hoc蛋白在噬菌体黏附肠黏液中的作用以及结合位点的变化，为旨在预防和控制肠道病原体的基于噬菌体的策略提供了关键见解。重要性抗生素耐药性病原菌的增加引发了人们对噬菌体疗法作为一种有前途的替代方法的新兴趣，特别是由于噬菌体的宿主特异性，其可用于靶向肠道病原体。然而，临床应用表明，许多噬菌体在消除肠道内细菌方面无效，主要是由于噬菌体与肠道环境之间的复杂相互作用。然而，这些相互作用背后的机制仍知之甚少。我们之前的研究表明，一种T4样噬菌体通过其Hoc蛋白与黏液中的MUC2相互作用而黏附于肠黏膜。这种模式在T4样噬菌体中是否普遍存在仍不清楚。在这里，我们对一种T4样噬菌体的变体Hoc蛋白进行了表征，并确定了该蛋白内的新结合位点。我们的研究结果表明，Hoc与MUC2之间的相互作用可能很常见，但关键结合位点因具体噬菌体而异。
