Engineered Treg therapy for pediatric Crohn's disease. - Summary Pediatric Crohn’s disease (CD) is a rare and chronic immune-mediated condition that is managed, but not cured, with continuous anti-inflammatory/immunosuppressive drugs. The condition leads to impaired growth, poor quality of life, and irreversible organ damage that often necessitates surgery, although surgery does not usually fully resolve or control the disease. Gut epithelial damage is critical to disease pathogenesis, but no current interventions aim to promote repair of the gut epithelium. Independent of the pathogenesis, regulatory T cells (Tregs) as CD therapeutics, have gained much attention for their potential to be impactful across many pathogenic CD manifestations. Indeed, Tregs can exert dual functions dampening the dysfunctional immune system in CD and contribute to tissue healing and regeneration. However, the current approaches to obtain Treg cells for clinical use have many hurdles and their use in CD has been difficult to explore. Our group has established a process to efficiently generate Treg-like cells, converting effector T cells by lentiviral transfer of the FOXP3 coding region, the essential transcription factor for Treg development and function. We have extensively characterized these engineered Tregs, called CD4LVFOXP3 cells, and we are gaining knowledge of their safety and efficacy in vivo in patients with IPEX syndrome. IPEX syndrome is considered a very early onset (VEO)-IBD, resembling pediatric CD, and manifesting with severe enteropathy, especially affecting the small intestine, and other autoimmune manifestations. CD4LVFOXP3 Treg-like cell product is currently in Phase 1 clinical trial at Stanford as a treatment for IPEX syndrome (NCT05241444). We propose that the clinical applicability of CD4LVFOXP3 goes beyond IPEX syndrome whereby administration could enhance gut epithelial cell regeneration and promote immune-modulation in pediatric CD. Here, we propose to test the efficacy of CD4LVFOXP3 in pediatric CD using 2 complementary models: 1. An organoid culture system derived from crypts from ileum tissues (called enteroids) obtained from pediatric CD patients that recapitulate the gut epithelial structure and function, including mucus production, regeneration and differentiation capacity, and epithelial barrier functions; and 2. a humanized mouse model of colitis, as the best available for pediatric CD, that shows impaired survival, inflammation and infiltration of T cells in the gut. In these mice, CD-like pathologies can be induced using the well-established trigger, 2,4,6-trinitrobenzene sulfonic acid (TNBS). Using these systems, we will test the hypothesis that CD4LVFOXP3 can provide a therapeutic modality for patients with pediatric CD by a) promoting tissue repair and regeneration and b) exerting immune suppression towards pathogenic effector T cells. Our goal is to use these systems to perform the required key pre-clinical studies to advance CD4LVFOXP3 Treg-like cells as a therapeutic for pediatric CD patients.
