Paneth cells are specialized secretory epithelial cells located at the base of the crypts of Lieberkühn in the small intestine.
Paneth cells are integral to the defense and maintenance of the small intestine through their secretion of antimicrobial peptides, support of stem cell niches, and modulation of immune responses.
Paneth cells play a crucial role in maintaining intestinal homeostasis and host defense.
These cells are characterized by their prominent eosinophilic granules, which contain a variety of antimicrobial peptides and proteins, such as α-defensins, lysozyme, and secretory phospholipase A2.
These antimicrobial substances are secreted into the intestinal lumen to regulate the composition of the gut microbiota and protect against pathogenic bacteria.
Paneth cells also provide essent factors for the maintenance and regulation of intestinal stem cells.
They secrete growth factors such as Wnt ligands, epidermal growth factor, and transforming growth factor-α, which are critical for the proliferation and differentiation of stem cells within the intestinal crypts.
Paneth cells also play a role in immune modulation, responding to immune signals, such as interferon-gamma (IFN-γ), which can induce degranulation and the release of their antimicrobial contents.
They respond as part of the broader immune defense mechanism to maintain gut integrity and prevent infections.
Dysfunction or loss of Paneth cells has been associated with several gastrointestinal disorders, including Crohn’s disease, necrotizing enterocolitis, and graft-versus-host disease.