An “anaerobic invisible” genetically engineered bacterium for periodontitis treatment through temporal modulation on microenvironment
Jiwei Sun, Junshuai Zhang, Haoqi Lei, Qingming Tang, Pingping Han, Yutian Xia, Ronghua Deng, Yifan Wang, Yunsong Shi, Junyuan Zhang, Yifan Zhang, Zhenshuo Han, Yingjia Huang, Yuzhou Wu, L. Chen
Abstract
Periodontitis is a highly prevalent chronic inflammatory disease, primarily driven by microbial dysbiosis and subsequent dysregulation of host immune responses. Therefore, targeting the pathogenesis, modulating the balance of periodontal microbiota, and subsequently controlling local inflammatory responses may offer an effective therapeutic strategy for periodontitis. Here, we propose a “bacteria-versus-bacteria” temporal therapeutic strategy and developed a genetically engineered strain HbEcN-PEI-MTZ@MnO 2 (HEpM) for periodontitis. This two-stage temporal therapy begins with pH-responsive release of metronidazole (MTZ) anchored on HEpM, eliminating periodontal pathogens and rebalancing the microbial dysbiosis. Concurrently, the engineered HEpM was endowed with a local oxygen supply system via the expression of Vitreoscilla hemoglobin (VHb), which enables HEpM to release oxygen as an oxygen-protective barrier forming a protective "anaerobic invisible cloak" that safeguards HEpM from the self-inflicted cytotoxicity of metronidazole. In the second therapeutic phase, remote thermal activation triggers the expression of anti-inflammatory enzymes to mitigate oxidative stress induced by microbial dysbiosis. Consequently, HEpM temporal therapy effectively reshaped the oral microbial community, reducing periodontal pathogens and biofilm formation. Single-cell RNA sequencing analysis further revealed a reduction in inflammatory CXCL1 + fibroblasts and enhanced fibroblast-centered intercellular communication, which facilitated immune microenvironment remodeling. This study establishes a smart, bacteria-based platform for temporal and targeted therapy of periodontitis, offering a novel paradigm for precision treatment of inflammatory diseases.