RNA regulatory circuits in allergic airway inflammation - PROJECT SUMMARY/ABSTRACT Asthma is a chronic inflammatory airway condition with high global prevalence causing significant morbidity and mortality. Allergic, “type 2” (T2), inflammation is the defining feature of asthma in many patients. Type 2 T helper (Th2) cells and the airway epithelium, acting through the canonical T2 cytokines IL-4 and IL-13, have central roles in asthma. Polarization of T cells towards a Th2 phenotype via IL-4 stimulation creates a pool of Th2 cells that are a major source of IL-13 in the airways. Sustained airway epithelial exposure to IL-13 causes goblet cell metaplasia and stimulates the secretion of chemokines that recruit inflammatory cells to the lung. When left unchecked, these changes amplify over time, increasing disease severity and promoting exacerbations that carry high morbidity and mortality. The mechanisms that control the magnitude and duration of T2 signaling in asthma are not well understood. In this proposal, we seek to identify RNA regulatory circuits that drive persistent T2 inflammation in T cells and the airway epithelium. Post-transcriptional regulation is an important mechanism that allows cells to tune the intensity of inflammatory responses. Interactions between 3’ untranslated regions (UTRs) on mRNAs and RNA binding proteins (RBPs) are key to this regulatory level. RNA binding proteins interact with the 3’ UTRs, dictating transcript stability, degradation, and localization. These circuits give cells dynamic control over the flow of transcriptomic information into cellular actions. Post-transcriptional regulation is understudied in asthma and presents the potential to define novel mediators of T2 inflammation. Our lab recently identified the STAT6 3’ UTR as a potentially important post-transcriptional regulatory element in T2 high asthma. Signal transducer and activator of transcription 6 (STAT6) is a critical mediator of T2 gene expression programming, acting as a transcription factor in response to IL-4 and IL-13. The STAT6 3’ UTR has multiple regions with protein occupancy and contains a SNP (rs1059513) that is highly associated with asthma and allergy, suggesting regulatory control that may dictate sensitivity to IL-4 and IL-13. Through high resolution mapping, we seek to identify functional elements across the STAT6 3’ UTR and their role in regulating the T2 signaling intensity in T cells and the airway epithelium. We will assess how these functional elements control gene expression, cytokine secretion, and epithelial cell differentiation. We have also identified candidate RBP regulators of T2 inflammation in the airway epithelium which include IGF2BP3, ZFP36L1, and ZFP36L2. Using CRISPR activation and interference, we will evaluate how these proteins control IL-13 mediated gene expression, pathologic mucus accumulation, and airway epithelial cell differentiation. These studies will illuminate clinically relevant post-transcriptional circuits in asthma and nominate novel pathways for potential therapeutic targeting. This project will be completed through a postdoctoral fellowship at UCSF and will utilize comprehensive institutional support and resources to prepare the applicant for an independent research career.
