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Principal Investigator: Rodney D Newberry
Organization: WASHINGTON UNIVERSITY
Fiscal Year: 2024
Award: $436,629
Funding agency: National Institute of Diabetes and Digestive and Kidney Diseases
The body's largest collection of immune cells underlies the single layer epithelium lining the gastrointestinal (GI)
tract and monitors the luminal contents, which includes trillions of microbes, their products, and substances from
the diet. The basal tone of the healthy gut immune system is tolerogenic, despite being exposed to trillions of
microbes and their products. While this strong tolerogenic capacity is beneficial to the host to avoid inflammatory
responses to innocuous dietary and commensal antigens in the healthy state, the inability to dampen this
tolerogenic capacity could be detrimental in the setting of enteric infection and inappropriately dampening this
tolerogenic capacity could underlie the pathogenesis of intestinal inflammatory diseases. We propose that the
gut has a capacity to turn off tolerogenic responses and generate inflammatory responses. While great progress
has been made in elucidating the role of specific immune cell subsets, cytokines, and other factors promoting
tolerance or immunity, how the gut immune system switches from tolerogenic responses in the steady-state to
protective immunity when needed remains a significant gap in our understanding. Completion of the studies
outlined in this proposal will fill this void in our understanding by identifying how inhibiting a major pathway
delivering luminal substances activates cellular and humoral immune responses at the mucosa.
In prior cycles of this award we have identified how goblet cell associated antigen passages (GAPs) are
formed, the stimulus inducing GAPs in the steady-state, acetylcholine (ACh), the stimuli and receptors regulating
GAP formation, including the luminal microbiota, cytokines, and epidermal growth factor receptor (EGFR)
ligands, and the properties of GAPs in various regions of the GI tract. Further we have identified roles for GAPs,
when physiologically present, in supporting tolerance to luminal substances including dietary and commensal
microbial antigens. Moreover, we have now assembled genetic and pharmacologic models for the manipulation
of GAPs and are poised to dissect the role of GAP inhibition in promoting protective/inflammatory immunity in
the absence of enteric infection or overt changes in the gut microbiota. Based upon our prior studies and
preliminary observations we hypothesize that when GAPs form in the steady state, they act to imprint the
immune system to promote tolerance and when small intestine (SI) GAPs are inhibited they participate in a
cascade of events promoting protective immunity. To explore this hypothesis we propose to (Aim 1) define the
LP-APCs phenotypes, the origins of Th17 and TFH cells that expand, and the durability of the response that
occurs when SI GAPs are inhibited, (Aim 2) define the drivers and specificities of the B cell responses arising
when SI GAPs are inhibited and (Aim 3) determine if SI GAP inhibition improves outcomes and is required for
appropriate responses during enteric infection.
Terms: <Acetylcholine><Affect><Alimentary Canal><Antigen-Presenting Cells><Antigens><Award><B blood cells><B cell><B cells><B-Cells><B-Lymphocytes><B-cell><Bacteria><Blood Plasma Cell><Cell Body><Cell Mediated Immunology><Cell-Mediated Immunity><Cells><Cellular Immunity><Collection><Data><Diet><Digestive Tract><EGF Receptor><EGFR><ERBB Protein><Epidermal Growth Factor Receptor><Epidermal Growth Factor Receptor Kinase><Epidermal Growth Factor Receptor Protein-Tyrosine Kinase><Epidermal Growth Factor-Urogastrone Receptors><Epithelium><Event><Exposure to><GI Tract><GI microbiota><Gastrointestinal Tract><Gastrointestinal microbiota><Gastrointestinal tract structure><Genetic><Goblet Cells><Grant><HER1><Humoral Immunities><Immune><Immune response><Immune system><Immunes><Immunity><Immunological response><Infection><Inflammatory><Inflammatory Bowel Diseases><Inflammatory Bowel Disorder><Inflammatory Response><Intestinal><Intestines><Lamina Propria><Ligands><Lymphatic Tissue><Lymphoid Follicle><Lymphoid Tissue><Macrophage><Maps><Mice><Mice Mammals><Microbe><Modeling><Monitor><Mucosa><Mucosal Tissue><Mucous Membrane><Murine><Mus><Mφ><Nature><Outcome><Pathogenesis><Pathway interactions><Phenotype><Physiologic><Physiological><Plasma Cells><Plasmacytes><Property><Receptor Protein><Reporter><Role><Small Intestinal Goblet Cell><Specificity><Stimulus><T cell response><TGF-alpha Receptor><Time><Tissue Expansion><Transforming Growth Factor alpha Receptor><Urogastrone Receptor><accessory cell><alimentary tract><antibody-based immunity><bowel><c-erbB-1><c-erbB-1 Protein><commensal bacteria><commensal bacterial species><cytokine><dietary><diets><digestive canal><enteral infection><enteric infection><enteric microbial community><enteric microbiota><enteric pathogen infection><enteropathogen infection><enteropathogenic infection><erbB-1><erbB-1 Proto-Oncogene Protein><erbBl><fighting><gastrointestinal homeostasis><gastrointestinal microbial flora><gut commensal><gut community><gut flora><gut microbe community><gut microbial community><gut microbial composition><gut microbial consortia><gut microbiota><gut microbiotic><gut microflora><host response><immune system response><immunogen><immunoresponse><imprint><improved outcome><infected with enteropathogen><inflammatory disease of the intestine><inflammatory disorder of the intestine><intestinal autoinflammation><intestinal flora><intestinal homeostasis><intestinal infection><intestinal microbiota><intestinal microflora><intestinal tract microflora><intestine infection><microbial antigen><microbial consortia><microbial flora><microbiota><microflora><microorganism antigen><multispecies consortia><novel><pathogen><pathway><pharmacologic><plasmocyte><programs><proto-oncogene protein c-erbB-1><receptor><response><social role>