Mechanisms of antiviral immunity and tolerance in the intestinal epithelium of Jamaican Fruit Bats

Summary
The gastrointestinal (GI) tract is a major target organ for viral infection in bats, but infections rarely cause
typical symptoms of viral enteritis such as diarrhea. The long-term goal of our project is to understand the
specific innate immune response mechanisms of the intestinal epithelium that enable bats to sustain viral
infection without experiencing cytopathic effects and intestinal barrier dysfunction. We hypothesize that
protective type I and type III interferon (IFN) responses in Jamaican Fruit Bats (Artibeus jamaicensis, JFBs)
enable persistent, asymptomatic viral infection of the gastrointestinal epithelium. To test our hypothesis, we will
utilize a novel in vitro model of the JFB intestine, 3-D enteroids, which are complex long-term cultures of
primary intestinal epithelial cells generated from adult tissue-derived stem cells. Responses in the gut
epithelium of JFBs will be compared to those induced in human enteroids. In Aim 1, we will define type I/III IFN
responses of JFB enteroids to viral infection. In Aim 2, we will determine to what extent type I/III IFNs impact
viral replication and barrier function in the gastrointestinal epithelium of JFBs. We will analyze intestinal
epithelial cell responses to three single-stranded RNA viruses that can infect JFB cells: H18N11 influenza
virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and Cedar virus, a non-pathogenic
henipavirus. Specifically, we will analyze the kinetics of viral replication and type I/III IFN activation in the
enteroids and will also perform a comprehensive proteomics analysis of virus-infected intestinal epithelial cells.
To assess the role of virus-induced type I/III IFNs for gastrointestinal epithelial pathology, IFN signaling will be
induced or inhibited, and the impact on enteroid susceptibility to viral infection will be analyzed. We also will
measure epithelial cell viability, barrier and repair functions that are commonly disrupted during viral enteritis.
Our project is technologically innovative, because we will, for the first time, analyze viral infection in enteroid
cultures derived from JFBs and because we also will perform a complete proteome analysis of the JFB
intestinal epithelium. The proposed work is conceptually innovative, because it will define how virus-induced
type I/III IFNs impact intestinal epithelial function and integrity. Our proposed work is significant, because it will
provide novel insights in the epithelial cell-intrinsic innate immune mechanisms involved in asymptomatic
infection of the bat intestine with viral pathogens, which has important implications for potential pathogen
spillover events.

Grant Number: 5R21AI169536-02
NIH Institute/Center: NIH
Principal Investigator: Diane Bimczok