Paneth cells, antimicrobial peptides and maintenance of intestinal homeostasis

• Published in: Nature reviews. Microbiology Vol. 9; no. 5; pp. 356 - 368
• Main Authors: Salzman, Nita H, Bevins, Charles L
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-05-2011; Nature Publishing Group
• Subjects: 631/250/347; 631/326/22; 692/698/2741/2135; 692/699/1503/1581/257; Animals; Antimicrobial Cationic Peptides - immunology; Bacteria; Biomedical and Life Sciences; Defense; Diseases; Epithelium; Health aspects; Homeostasis; Humans; Immune system; Immunity, Mucosal; Infectious Diseases; Inflammatory Bowel Diseases - immunology; Intestine, Small - immunology; Intestine, Small - microbiology; Life Sciences; Medical Microbiology; Metagenome; Microbiology; Microbiota; Microbiota (Symbiotic organisms); Microorganisms; Paneth Cells - cytology; Paneth Cells - immunology; Parasitology; Peptides; Physiological aspects; review-article; Small intestine; United States; Virology; United States; United States > US
• ISSN: 1740-1526; 1740-1534
• DOI: 10.1038/nrmicro2546

Key Points
The intestinal microbiota is important for many physiological functions and contributes to host defence by providing resistance to colonization by pathogens and through effects on the mucosal immune system.
Paneth cells are specialized secretory epithelial cells that are located in the small intestinal crypts and produce a diverse group of antimicrobial, immune system-stimulating and trophic molecules.
Paneth cells have several essential roles for the maintenance of immune homeostasis, such as regulating the composition of the intestinal microbiota, defending against intestinal pathogens and supporting the function of crypt epithelial stem cells.
Antimicrobial α-defensins are essential effectors that are produced and secreted by Paneth cells. These effectors modulate acquired immunity in the host through their ability to regulate the composition of the intestinal microbiota.
There are numerous susceptibility genes associated with an increased risk of developing Crohn's disease, and many of these genes affect Paneth cell function, strongly suggesting a critical role for these cells in the pathogenesis of Crohn's disease.
The gut microbiota and the host immune system are in a careful balance. The Paneth cells in the endothelium of the small intestine produce a large array of antimicrobial proteins that help set this balance and protect the host from pathogens.
Building and maintaining a homeostatic relationship between a host and its colonizing microbiota entails ongoing complex interactions between the host and the microorganisms. The mucosal immune system, including epithelial cells, plays an essential part in negotiating this equilibrium. Paneth cells (specialized cells in the epithelium of the small intestine) are an important source of antimicrobial peptides in the intestine. These cells have become the focus of investigations that explore the mechanisms of host–microorganism homeostasis in the small intestine and its collapse in the processes of infection and chronic inflammation. In this Review, we provide an overview of the intestinal microbiota and describe the cell biology of Paneth cells, emphasizing the composition of their secretions and the roles of these cells in intestinal host defence and homeostasis. We also highlight the implications of Paneth cell dysfunction in susceptibility to chronic inflammatory bowel disease.