The proposal details a comprehensive five years training program to expand my skills as a physician-scientist. The research plan is focused on JAK-STAT pathway in Celiac Disease (CeD), but the training plan includes extensive didactics in human subject research, bioinformatics and laboratory-based training on T cell immunology. CeD is an immune mediated gastrointestinal disease that arises in patients with a permissive HLA-DQ2/HLA-DQ8 genetic background. The only available treatment for CeD is to follow a gluten-free diet. Patients with germline gain-of-function (GOF) STAT3 mutations and Down Syndrome have an estimated 40- fold and 5-fold higher risk of CeD, respectively, than the general population, along with a predisposition for other autoimmune diseases, including thyroiditis and Type I Diabetes. Patients with Down Syndrome have three copies of the gene for interferon (IFN) receptors on chromosome 21 and thus constitutive JAK-STAT activation. The central hypothesis is that interferon and cytokines mediated JAK-STAT overactivation may cause loss of T cell tolerance to gluten and an increased risk for CeD. The overall goal of this research is to investigate the mechanism of JAK-STAT activation in the pathogenesis of CeD. To accomplish this, first, we will conduct genetic investigation in 100 index cases with familial CeD and search for genetic variants in the JAK-STAT pathway. We will also expand our cohort of CeD patients with known genetic diseases affecting JAK-STAT activation, include patients with GOF-STAT3 and DS. Second, we will assess the key molecules in the JAK-STAT pathway, including agonists, receptors, STAT and their phosphorylated forms, ISGs in monocyte and CD4+ T cells to identify a molecular signature of active CeD. Third, we will investigate the mechanisms of JAK-STAT overactivation on gluten-specific CD4+ T cells through both single cell RNA-Seq and amplified T cell libraries, followed by testing the functional impact of JAK inhibitors on gluten-specific T cells. The results of this study will delineate JAK-STAT activation and its potential as a therapeutic target for Celiac Disease. Furthermore, through the proposed complementary career development plan, I will gain additional training in clinical investigation on the genetics and immunology of CeD; advanced bioinformatic analysis with RNA-seq; and laboratory-based training in gluten specific CD4+ T cells biology. Throughout this research and career development activities, I will be mentored by a team lead by Dr. Timothy Wang, an internationally recognized physician-scientist and an expert in inflammatory cytokines and their role in human gastrointestinal diseases. I am committed to a career as an independent investigator in patient-oriented translational research; and have designed my training plan to acquire the knowledge and skills needed to make a meaningful and substantial contribution to the field by using a functional genetics approach to discover the therapeutic targets in gastrointestinal diseases.

Individuals with GOF-STAT3 mutations and Down Syndrome have a forty- and five-fold greater risk, respectively, of developing Celiac Disease, while the treatment options are limited to a gluten-free diet. We hypothesize that JAK-STAT overactivation is a primary genetic cause of the predisposition to Celiac Disease. The proposed research will collect samples and clinical data from familial CeD, GOF-STAT3-CeD and DS-CeD individuals and will investigate the JAK-STAT pathway in the pathogenesis of gluten-specific CD4+ T cells. Overall, the study will provide a proof-of-concept that JAK inhibitors may be beneficial for some Celiac Disease patients with an JAK-STAT dependent signature.