Oral Antimicrobial Peptides-AMPs: Types and role in the oral cavity/ mouth

Last updated: Jan 9, 2020  |  827 Views  |  Oral and dental care

Oral Antimicrobial Peptides-AMPs: Types and role in the oral cavity/ mouth

The oral mucosa has three types of antimicrobial defenses: physical barrier of the epithelial layer; nonspecific (innate) immunity derived from salivary constituents, neutrophils, and epithelial antimicrobial peptides; and adaptive immunity associated with mucosa-associated lymphatic tissues.

Antimicrobial peptides (AMPs) are a wide-ranging class of host-defense molecules that act early to contest against microbial invasion and challenge. These are small cationic peptides that play an important in the development of innate immunity.

The oral cavity is a unique environment in which antimicrobial peptides play a key role in maintaining oral/ dental health. Antimicrobial peptides (AMPs) are natural antibiotics that are found in each of these compartments: in the saliva, in the epithelium, and in neutrophils and serve defensive purposes. Evidence is accumulating that AMPs are important contributors to maintaining the balance between health and disease as part of the host innate immune response. They have generally been considered to contribute to mucosal health.



Present evidence suggests that α-defensins, β-defensins, LL-37, histatin, and other antimicrobial peptides and proteins have distinct but overlapping roles in maintaining oral health. The expression of the inducible hBD-2 in normal oral epithelium, and the apparent differential signaling in response to commensal and pathogenic organisms, provides new insights into innate immunity in this body site. Commensal bacteria are excellent inducers of hBD-2 in oral epithelial cells, suggesting that the commensal bacterial community acts in a manner to benefit the overall innate immune readiness of oral epithelia. This may have major significance for understanding host defense in the complex oral environment. Evidence is accumulating that AMPs are important contributors to maintaining the balance between health and disease as part of the host innate immune response. They have generally been considered to contribute to mucosal health. It is logical that these AMPs are biological factors that influence caries susceptibility and development as well. Recent research suggests the importance of the defensins and the cathelicidin LL37 as antibacterial agents in the oral cavity.

The neutrophil alpha-defensins, (human neutrophil peptides 1–3 (HNP1–3)), are one of the mechanisms for non-oxidative microbial killing and are found in gingival crevicular fluid. The human cathelicidin peptide, LL37, is in neutrophils, inflamed epithelia, submandibular salivary glands and saliva. Their potential role in protecting tooth structure from bacterially-induced caries, either by direct killing or by prevention of biofilm formation on the tooth surface. The defensins and cathelicidin have broad antimicrobial activity against gram-negative and gram-positive bacteria and are effective against oral microorganisms such as Streptococcus mutans, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans. The co-expression in saliva of LL37 and defensins with peptides such as histatin, proline-rich proteins, and calprotectin may provide a natural antibiotic barrier. The prediction of caries risk has been of long-standing interest and is very important for development of new preventive strategies. This is especially significant for young children and for children with special health care needs.



Reference:
- Periodontal disease and gingivitis, https://mpkb.org/home/diseases/periodontal

- Oral antimicrobial peptides: Types and role in the oral cavity, Zohaib Khurshid, Mustafa Naseem, Zeeshan Sheikh, Shariq Najeeb, Sana Shahab, and Muhammad Sohail Zafar, Saudi Pharm J. 2016 Sep; 24(5): 515–524.
- Recent advances in the field of antimicrobial peptides in inflammatory diseases, Patricia Méndez-Samperio, Adv Biomed Res. 2013; 2: 50.

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