title: Expansion of Paneth cell population in response to enteric Salmonella enterica serovar Typhimurium infection.
abstract: Paneth cells residing at the base of the small intestinal crypts contribute to the mucosal intestinal first line defense by secreting granules filled with antimicrobial polypeptides including lysozyme. These cells derive from the columnar intestinal stem cell located at position 0 and the transit amplifying cell located at position +4 in the crypts. We have previously shown that Salmonella enterica serovar Typhimurium (ST), a leading cause of gastrointestinal infections in humans, effects an overall reduction of lysozyme in the small intestine. To extend this work, we examined small-intestinal tissue sections at various time points after ST infection to quantify and localize expression of lysozyme and assess Paneth cell abundance, apoptosis, and the expression of Paneth cell differentiation markers. In response to infection with ST, the intestinal Paneth cell-specific lysozyme content, the number of lysozyme-positive Paneth cells, and the number of granules per Paneth cell decreased. However, this was accompanied by increases in the total number of Paneth cells and the frequency of mitotic events in crypts, by increased staining for the proliferation marker PCNA, primarily at the crypt side walls where the transit amplifying cell resides and not at the crypt base, and by apoptotic events in villi. Furthermore, we found a time-dependent upregulation of first β-catenin, followed by EphB3, and lastly Sox9 in response to ST, which was not observed after infection with a Salmonella pathogenicity island 1 mutant deficient in type III secretion. Our data strongly suggest that, in response to ST infection, a Paneth cell differentiation program is initiated that leads to an expansion of the Paneth cell population and that the transit amplifying cell is likely the main progenitor responder. Infection-induced expansion of the Paneth cell population may represent an acute intestinal inflammatory response similar to neutrophilia in systemic infection.
authors: Department of Biological Sciences, California State University Los Angeles, Los Angeles, California, USA.
authors: Nadine R
authors: NR
authors: Martinez Rodriguez
authors: Marjannie D
authors: MD
authors: Eloi
authors: Alexandria
authors: A
authors: Huynh
authors: Teresa
authors: T
authors: Dominguez
authors: Annie H Cheung
authors: AH
authors: Lam
authors: Dayana
authors: D
authors: Carcamo-Molina
authors: Zeina
authors: Z
authors: Naser
authors: Robert
authors: R
authors: Desharnais
authors: Nita H
authors: NH
authors: Salzman
authors: Edith
authors: E
authors: Porter
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D003593:Cytoplasm / Q000737:chemistry; D003594:Cytoplasmic Granules; D005260:Female; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D007421:Intestine, Small / Q000276:immunology / Q000473:pathology; D051379:Mice; D009113:Muramidase / Q000032:analysis; D019879:Paneth Cells / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000276:immunology* / Q000473:pathology; D012486:Salmonella typhimurium / Q000276:immunology*
chemical_list: D009113:Muramidase