Intestinal organoid-based models for drug discovery in pediatric inflammatory bowel disease.

A curative pharmacological therapy for inflammatory bowel disease (IBD) does not exist and the therapeutic approach is mainly aimed at the treatment and control of inflammation. IBD is particularly severe in pediatric patients and therapy is more aggressive than in adults. While the cause of IBD is still unknown, accumulating evidence suggests that the intestinal epithelium plays an important role in its pathogenesis. Substances able to promote epithelial regeneration may have a therapeutic role, as recently demonstrated for IL22. In this context, the development of a new category of drugs that are targeted to epithelial cell barrier functions and promote tissue repair may become one of the therapeutic choices to achieve mucosal healing in patients with IBD. Thanks to the recent development of intestinal organoids, it is now possible to culture the intestinal tissue of the individual patient, which reproduces the genetic and epigenetic features and the main functions of the organ of origin. The aim of this study is to identify innovative drugs for pediatric IBD by applying intestinal organoid based models. Therefore, a focused drug repurposing screen will be performed using patient-derived intestinal organoids, evaluating the capability of the compounds to promote epithelial proliferation. The activity of selected compounds will be then validated by measuring the expression of candidate genes, involved in the epithelial injury and immune regulation, and the production of candidate inflammatory cytokines on pediatric IBD organoid lines. From another perspective, preliminary data showed that the cytokine CD70, the ligand for CD27, is critical to sustain T cell-mediated intestinal inflammation by NF-kB activation and its expression is higher in IBD compared to non-IBD derived organoids, suggesting a potential role of intestinal epithelial cells in the regulation of immune response. Consequently, another significant outcome of this project will be the identification of selective binders for CD70, a new candidate therapeutic target for IBD, by a structure-based virtual screening. In this part of the project, the objective is to design, synthesize, and characterize a series of compounds capable of inhibiting the protein-protein interaction (PPI) between CD70 and CD27. In particular, the CD27 portion in complex with CD70 will be used as a template to guide the computational design of PPI inhibitors, relying on the CD70/CD27 X-ray crystal structure, which has been recently deposited in the Protein Data Bank. Such compounds will be then tested for their ability to block CD70/CD27 costimulatory pathway by coculturing IBD patient-derived intestinal organoids with CD27/NF-kB reporter-Jurkat recombinant cell line. The expected results could lead to identify intestinal epithelial cells-based therapies which may have regenerative or protective effects on the damaged epithelium, and thus promote mucosal healing.

A curative pharmacological therapy for inflammatory bowel disease (IBD) does not exist and the therapeutic approach is mainly aimed at the treatment and control of inflammation. IBD is particularly severe in pediatric patients and therapy is more aggressive than in adults. While the cause of IBD is still unknown, accumulating evidence suggests that the intestinal epithelium plays an important role in its pathogenesis. Substances able to promote epithelial regeneration may have a therapeutic role, as recently demonstrated for IL22. In this context, the development of a new category of drugs that are targeted to epithelial cell barrier functions and promote tissue repair may become one of the therapeutic choices to achieve mucosal healing in patients with IBD. Thanks to the recent development of intestinal organoids, it is now possible to culture the intestinal tissue of the individual patient, which reproduces the genetic and epigenetic features and the main functions of the organ of origin. The aim of this study is to identify innovative drugs for pediatric IBD by applying intestinal organoid based models. Therefore, a focused drug repurposing screen will be performed using patient-derived intestinal organoids, evaluating the capability of the compounds to promote epithelial proliferation. The activity of selected compounds will be then validated by measuring the expression of candidate genes, involved in the epithelial injury and immune regulation, and the production of candidate inflammatory cytokines on pediatric IBD organoid lines. From another perspective, preliminary data showed that the cytokine CD70, the ligand for CD27, is critical to sustain T cell-mediated intestinal inflammation by NF-kB activation and its expression is higher in IBD compared to non-IBD derived organoids, suggesting a potential role of intestinal epithelial cells in the regulation of immune response. Consequently, another significant outcome of this project will be the identification of selective binders for CD70, a new candidate therapeutic target for IBD, by a structure-based virtual screening. In this part of the project, the objective is to design, synthesize, and characterize a series of compounds capable of inhibiting the protein-protein interaction (PPI) between CD70 and CD27. In particular, the CD27 portion in complex with CD70 will be used as a template to guide the computational design of PPI inhibitors, relying on the CD70/CD27 X-ray crystal structure, which has been recently deposited in the Protein Data Bank. Such compounds will be then tested for their ability to block CD70/CD27 costimulatory pathway by coculturing IBD patient-derived intestinal organoids with CD27/NF-kB reporter-Jurkat recombinant cell line. The expected results could lead to identify intestinal epithelial cells-based therapies which may have regenerative or protective effects on the damaged epithelium, and thus promote mucosal healing.