Porcine antimicrobial peptides: New prospects for ancient molecules of host defense

Abstract

-Antimicrobial peptides (AMPs) are small, endogenous, polycationic molecules that constitute a ubiquitous and significant component of innate immunity. These natural antibiotics have broad microbicidal activity against various bacteria, fungi, and enveloped viruses. Because most AMPs kill bacteria by physical disruption of cell membranes, which may prevent microorganisms from developing resistance against these agents, they are being explored as possible alternatives to conventional antibiotics. Pigs, like many other mammals, produce an impressive array of AMPs, which are synthesized predominantly by host leukocytic phagocytes or mucosal epithelial cells. Currently, more than a dozen distinct porcine AMPs have been identified and a majority belongs to the cathelicidin family. This review briefly summarizes recent advances in porcine AMP research with an emphasis on the diverse biological functions of each peptide. Mechanisms of action of these AMPs and their role in the resistance to infections are considered. Finally, the current status of pharmaceutical and agricultural uses of AMPs as well as future prospects for their application in the food animal industry is discussed.pig / antimicrobial peptide / cathelicidin / defensin / innate immunity Résumé -Peptides antimicrobiens porcins : nouvelles perspectives pour d'anciennes molécules de défense de l'hôte. Les peptides antimicrobiens sont de petites molécules endogènes, polycationiques, qui représentent un élément important et ubiquitaire des défenses immunes naturelles. Ces antibiotiques naturels ont un effet antimicrobien à large spectre, à la fois contre des bactéries, des moisissures et des virus enveloppés. Comme la plupart de ces peptides antimicrobiens tuent les bactéries par altération physique de leur membrane, ce qui peut éviter le développement de souches microbiennes résistantes à ces agents, ils représentent des alternatives possibles à l'emploi des antibiotiques classiques. Le porc, comme de nombreux autres mammifères, produit une gamme importante de peptides antimicrobiens, synthétisés pour l'essentiel par les leucocytes à activité phagocytaire, ou par les cellules épithéliales des muqueuses. Il y a actuellement plus d'une douzaine de peptides antimicrobiens identifiés chez le porc, dont la majorité fait partie de la famille des cathélicidines. Cet article résume les progrès récents accomplis dans le domaine des peptides antimicrobiens du porc, Vet. Res. 31 (2000) 277-296 277

Accompaniment of the polymorphism at defensin gene loci with milk productivity in Holstein Friesian and Egyptian cows

“…This result is in agreement with the result which obtained by both Exner et al (2000) and Zhang et al (2000), who postulated that segregating QTL's affecting dairy form and milk yield could exist near BM203 on chromosome 27. Many other previous studies were carried out to map or identify QTL's affecting milk production and health of dairy cattle.…”

Effects of a single nucleotide polymorphism in the chicken NK-lysin gene on antimicrobial activity and cytotoxicity of cancer cells

“…The structural and antimicrobial activities of NK-lysin have been investigated for more than a decade (5-7). The microbiocidal and tumor cytolytic activities of NK-lysin, like those of other saposin-like proteins, are believed to be a result of its ability to form pores in the cell membrane because of its α-helical structure (8). Hydrophobicity, cationicity, and relative size of hydrophobic and hydrophilic domains of AMPs generate diverse effects on membranes (9), although their specific contributions to activity are not known.…”

Role of intestinal epithelial cells in the innate immune defence of the pig intestine

“…In pigs, currently more than a dozen distinct anti-microbial peptides have been identified and a majority belong to the cathelicidin family [79].…”

“…Although α-defensins are the most abundant anti-microbial peptides in granules of polymorphonuclear cells or intestinal Paneth cells in many mammalian species [79], they have not been found in pigs. The porcine β-defensin mRNA is expressed abundantly in tongue epithelia and to a lesser extent throughout the respiratory and digestive tracts.…”