Enhancing a Wnt-Telomere Feedback Loop Restores Intestinal Stem Cell Function in a Human Organotypic Model of Dyskeratosis Congenita

Abstract

Patients with dyskeratosis congenita (DC) suffer from stem cell failure in highly proliferative tissues, including the intestinal epithelium. Few therapeutic options exist for this disorder, and patients are treated primarily with bone marrow transplantation to restore hematopoietic function. Here, we generate isogenic DC patient and disease allele-corrected intestinal tissue using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated gene correction in induced pluripotent stem cells and directed differentiation. We show that DC tissue has suboptimal Wnt pathway activity causing intestinal stem cell failure and that enhanced expression ofthe telomere-capping protein TRF2, a Wnt target gene, can alleviate DC phenotypes. Treatment withthe clinically relevant Wnt agonists LiCl or CHIR99021 restored TRF2 expression and reversed gastrointestinal DC phenotypes, including organoid formation invitro, and maturation of intestinal tissueand xenografted organoids invivo. Thus, the isogenic DC cell model provides a platform for therapeutic discovery and identifies Wnt modulation as a potential strategy for treatment of DC patients.