The human salivary antimicrobial peptide profile according to the oral microbiota in health, periodontitis and smoking

Antimicrobial peptides (AMPs) are a diverse family of peptides that defend the mucosal surfaces of the oral cavity and other locations. Many AMPs have multiple functions and properties; can influence aspects of innate defense; and influence colonization by microorganisms. The human oral cavity is home to the second most diverse microbiome and the health of the mouth is influenced by the presence of these bacteria as well as by extrinsic factors such as periodontitis and smoking. This study hypothesized that the AMP profile is different in the presence of extrinsic factors and that this would also be reflected in the bacteria present. The AMP profile was analysed by quantitative selected reaction monitoring mass spectrometry analysis and 40 bacterial species were quantified by DNA-DNA hybridization in saliva donated by 41 individuals. Periodontal status was assessed through dental examination and smoking status through medical charting. Periodontal health (in non-smokers) was associated with higher abundance of Ribonuclease 7, Protachykinin 1, Beta defensin 128, Lipocalin 1, bactericidal permeability-increasing protein (BPI) fold containing family B member 3 and Bone-marrow proteoglycan. Non-smoking periodontal disease was associated with abundance of Neutrophil defensin 1 and Cathelicidin. However 7 AMPs were over-abundant in periodontal disease in smokers, namely Adrenomedullin , Eosinophilperoxidase, 3 different Histones, Myeleperoxidase and Neutrophil defensin 1. There was no differentially abundant AMPs in smokers versus non-smokers with periodontal health. Correlation network inference of healthy non-smokers, healthy smokers, non-smoking periodontitis or smoking periodontitis donors demonstrated very different networks growing in complexity with increasing numbers of stressors. The study highlights the importance of the interaction between the oral cavity and its resident microbiota and how this may be influenced by periodontal disease and smoking.