title: Three-dimensional tissue assemblies: novel models for the study of Salmonella enterica serovar Typhimurium pathogenesis.
abstract: The lack of readily available experimental systems has limited knowledge pertaining to the development of Salmonella-induced gastroenteritis and diarrheal disease in humans. We used a novel low-shear stress cell culture system developed at the National Aeronautics and Space Administration in conjunction with cultivation of three-dimensional (3-D) aggregates of human intestinal tissue to study the infectivity of Salmonella enterica serovar Typhimurium for human intestinal epithelium. Immunohistochemical characterization and microscopic analysis of 3-D aggregates of the human intestinal epithelial cell line Int-407 revealed that the 3-D cells more accurately modeled human in vivo differentiated tissues than did conventional monolayer cultures of the same cells. Results from infectivity studies showed that Salmonella established infection of the 3-D cells in a much different manner than that observed for monolayers. Following the same time course of infection with Salmonella, 3-D Int-407 cells displayed minimal loss of structural integrity compared to that of Int-407 monolayers. Furthermore, Salmonella exhibited significantly lower abilities to adhere to, invade, and induce apoptosis of 3-D Int-407 cells than it did for infected Int-407 monolayers. Analysis of cytokine expression profiles of 3-D Int-407 cells and monolayers following infection with Salmonella revealed significant differences in expression of interleukin 1alpha (IL-1alpha), IL-1beta, IL-6, IL-1Ra, and tumor necrosis factor alpha mRNAs between the two cultures. In addition, uninfected 3-D Int-407 cells constitutively expressed higher levels of transforming growth factor beta1 mRNA and prostaglandin E2 than did uninfected Int-407 monolayers. By more accurately modeling many aspects of human in vivo tissues, the 3-D intestinal cell model generated in this study offers a novel approach for studying microbial infectivity from the perspective of the host-pathogen interaction.
authors.affiliation: Program in Molecular Pathogenesis and Immunity, Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA. cnicker@tulane.edu
authors.forename: C A
authors.initials: CA
authors.lastname: Nickerson
authors.forename: T J
authors.initials: TJ
authors.lastname: Goodwin
authors.forename: J
authors.initials: J
authors.lastname: Terlonge
authors.forename: C M
authors.initials: CM
authors.lastname: Ott
authors.forename: K L
authors.initials: KL
authors.lastname: Buchanan
authors.forename: W C
authors.initials: WC
authors.lastname: Uicker
authors.forename: K
authors.initials: K
authors.lastname: Emami
authors.forename: C L
authors.initials: CL
authors.lastname: LeBlanc
authors.forename: R
authors.initials: R
authors.lastname: Ramamurthy
authors.forename: M S
authors.initials: MS
authors.lastname: Clarke
authors.forename: C R
authors.initials: CR
authors.lastname: Vanderburg
authors.forename: T
authors.initials: T
authors.lastname: Hammond
authors.forename: D L
authors.initials: DL
authors.lastname: Pierson
mesh_terms: D017209:Apoptosis; D001422:Bacterial Adhesion; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis; D015232:Dinoprostone / Q000096:biosynthesis; D006801:Humans; D007124:Immunoenzyme Techniques; D007413:Intestinal Mucosa / Q000166:cytology / Q000382:microbiology*; D008854:Microscopy, Electron; D008954:Models, Biological; D012486:Salmonella typhimurium / Q000472:pathogenicity*
chemical_list: D016207:Cytokines; D015232:Dinoprostone