Funding Agency: National Institutes of Health
Principal Investigator: Megan Stanifer, Ph.D.
Title: STING induced IFNL2/3 protects human intestinal epithelial cells from rotavirus infection
Award Period: 06/06/2025-05/31/2030
Project Summary: The double-stranded RNA virus rotavirus is one of the leading causes of enteric virus induced deaths worldwide. Upwards of 200,000 people, mostly children, die due to rotavirus infection each year. While several rotavirus vaccines have been developed and efficiently protect children in the developed world, they display poor efficacies in developing countries where they are needed the most; indicating that alternative strategies to combat rotavirus infection are greatly needed. Rotaviruses infect the intestinal epithelial cells lining the surface of the gastrointestinal tract. Upon rotavirus infection these cells upregulate type I and type III interferons to combat rotavirus infection. Recent work from our lab has shown that type I interferons are dispensable for controlling rotavirus infection. We found that type III interferons are the key cytokines which restrict rotavirus replication and spread in human intestinal epithelial cells. Humans express four type III interferons (IFNl1, IFNl2, IFNl3, and IFNl4). How each subtype of type III interferon is produced following virus infection and whether the different subtypes of type III interferon have subtype-specific antiviral properties remain mostly unknown. To unravel how rotaviruses induced type III interferons in human intestinal epithelial cells, we used genetic depletions and pharmacological inhibitors. We could show that intestinal epithelial cells produce type III interferons following rotavirus infection through both the RIG-like receptor (RLR) and STING pathways. These preliminary data report for the first time that rotavirus infection can be sensed by the STING pathway which normally is responsible for sensing DNA virus infection. In addition, we found that RLRs and STING each lead to the upregulation of distinct type III interferons: RLR activation upregulated IFNl1 and IFNl2/3 while STING led to the exclusive upregulation of IFNl2/3. To determine whether IFNl1 and IFNl2/3 were equally important to control rotavirus infection we genetically depleted them in our human intestinal epithelial cells. We found that IFNl1 was dispensable for controlling rotavirus infection while IFNl2/3 was critical for controlling rotavirus infection and spread. In this proposed project we will further investigate how STING is activated following rotavirus infection and determine how distinct type III interferon subtypes (IFNl1 vs IFNl2/3) can be upregulated depending on the pattern recognition receptor which is activated. Together these results will give us insight into tissue specific mechanisms used to combat viral infection and provide novel insight into whether IFNl2/3 could be implemented as anti-rotaviral therapeutic measure in areas of low vaccine efficacy.