Outer Membrane Vesicles Derived from Oral Bacteria Act as a Dagger in Host Immunity: Insight Tips from Local Diseases to Systemic Effects.

Outer membrane vesicles (OMVs) are secreted by gram-negative bacteria and are genetically and environmentally regulated. The contents of OMVs are derived from the outer membrane and periplasm of bacteria, that can act as virulence factors to attack host cells. In periodontitis, the OMVs of Porphyromonas gingivalis and other important periodontal pathogens can destroy the host structure, induce host immune responses, and promote periodontitis progression. In oral squamous cell carcinoma (OSCC), OMVs accelerate cancer spread and metastasis by regulating the gene expression of tumour cells. In addition to their role in oral diseases, OMVs can spread from the oral cavity to the whole body, thereby participating in the development of many diseases, including circulatory diseases, endocrine diseases, autoimmune diseases, and neurologic diseases. In this review, we introduce the biogenesis, basic structure, and roles of OMVs and comprehensively summarize the biological characteristics of OMVs from various oral bacteria. In addition, we describe the impact of OMVs on oral diseases as well as systemic health and emphasize their therapeutic potential as drug targets, antigens, and immune adjuvants for application in periodontitis and OSCC. Finally, we discuss in depth the future research directions, application prospects, and challenges of OMVs.