The gastrointestinal tract of mammals is inhabited by hundreds of distinct species of commensal microorganisms that exist in a mutualistic relationship with the host. The process by which the commensal microbiota influence the host immune system is poorly understood. We show here that colonization of the small intestine of mice with a single commensal microbe, segmented filamentous bacterium (SFB), is sufficient to induce the appearance of CD4+ T helper cells that produce IL-17 and IL-22 (Th17 cells) in the lamina propria. SFB adhere tightly to the surface of epithelial cells in the terminal ileum of mice with Th17 cells but are absent from mice that have few Th17 cells. Colonization with SFB was correlated with increased expression of genes associated with inflammation, anti-microbial defenses, and tissue repair, and resulted in enhanced resistance to the intestinal pathogen Citrobacter rodentium. Control of Th17 cell differentiation by SFB may thus establish a balance between optimal host defense preparedness and potentially damaging T cell responses. Manipulation of this commensal-regulated pathway may provide new opportunities for enhancing mucosal immunity and treating autoimmune disease.
Induction of intestinal Th17 cells by segmented filamentous bacteria.
Specimen part
View SamplesOur laboratory's interest is in understanding the molecular principles that underlie the regional organization of the mammalian metanephric kidney. Our goal is to generate a detailed spatial map of the cellular expression of selected regulatory genes during mammalian kidney development. The goal of this study is to identify a population of genes that are enriched in the renal vesicle (RV) and its derivatives using Wnt4 mutants.
Analysis of early nephron patterning reveals a role for distal RV proliferation in fusion to the ureteric tip via a cap mesenchyme-derived connecting segment.
Sex
View SamplesThe innate immune system is a two-edged sword; it is absolutely required for host defense against infection, but if left uncontrolled can trigger a plethora of inflammatory diseases. Here we used systems biology approaches to predict and validate a gene regulatory network involving a dynamic interplay between the transcription factors NF-B, C/EBP, and ATF3 that controls inflammatory responses. We mathematically modeled transcriptional regulation of Il6 and Cebpd genes and experimentally validated the prediction that the combination of an initiator (NF-B), an amplifier (C/EBP) and an attenuator (ATF3) forms a regulatory circuit that discriminates between transient and persistent Toll-like receptor 4-induced signals. Our results suggest a mechanism that enables the innate immune system to detect the duration of infection and to respond appropriately.
Function of C/EBPdelta in a regulatory circuit that discriminates between transient and persistent TLR4-induced signals.
Sex, Specimen part
View Samples