Neonatologist Boston Children's Hospital Harvard Medical School Boston, Massachusetts, United States
Background: Children with the rare disease Wnt2b deficiency (Wingless wingless-type MMTV integration site family, member 2B) are affected by severe intestinal inflammation and dysregulation leading to dependence on parenteral nutrition starting from the neonatal period. Wnt2b’s role in intestinal homeostasis is poorly understood.
Objective: To determine Wnt2b’s role in intestinal development, maintenance, and injury repair.
Design/Methods: We utilized a combination of in vitro and in vivo approaches to model the functions of Wnt2b. To investigate the importance of Wnt2b during development, we generated Wnt2b-deficient and control human iPS-derived intestinal organoids (HIOs), which contain both epithelium and mesenchyme and follow the developmental pattern from iPS cells to definitive endoderm to primordial gut to intestinal tissue. We also generated Wnt2b KO and control mice. To investigate the importance of Wnt2b in injury repair, we treated Wnt2b KO and control mice with intraperitoneal anti-CD3 antibody, an established model of small intestinal injury.
Results: Wnt2b-deficient HIOs form and can be propagated and are indistinguishable from controls (Fig. 1). Wnt2b KO mice were viable, normal in appearance, and show intestinal and colonic histology similar to controls (Fig. 2). Wnt2b KO mice treated with anti-CD3 antibody showed increased weight loss (Fig 3A) and significantly diminished crypt depth and villus length compared to controls during intestinal injury repair (Fig. 3B). Conclusion(s): We conclude that Wnt2b is not required for intestinal development or maintenance using Wnt2b-deficient HIOs and Wnt2b KO mice. In contrast, Wnt2b plays an important role during the intestinal injury repair response following CD3-induced injury in mice. These data provide fundamental insight into Wnt2b’s role in intestinal homeostasis.
Figure 1. Wnt2b mutant HIOs are viable. Top panel, control HIOs after 28 days in culture. Bottom panel, Wnt2b mutant HIOs.
Fig 2. Wnt2b KO mice have normal intestinal histology. Tops panel, control mouse intestinal histology. Bottom panel, Wnt2b KO mouse intestinal histology. All images at 200X total magnification.
Fig. 3 Wnt2b KO mice have impaired recovery after injury. A. Percent weight loss for WT control and Wnt2b KO mice 2 and 4 days after receiving IP injections of anti-CD3 antibody. B. Villus length on positive y-axis and crypt depth on negative y-axis for WT and KO mice on day 4 post CD3 injection.
Authors/Institutions: Amy E. O'Connell, Boston Children's Hospital, Boston, Massachusetts, United States; Wanshu Qi, Boston Children's Hospital, Boston, Massachusetts, United States; Jasmine Lin, Boston Children's Hospital, Boston, Massachusetts, United States; Amanda Harrington, Boston Children's Hospital, Boston, Massachusetts, United States; Jeffrey D. Goldsmith, Boston Children's Hospital, Boston, Massachusetts, United States; Pankaj Agrawal, Boston Children's Hospital, Boston, Massachusetts, United States; David Breault, Boston Children's Hospital, Boston, Massachusetts, United States
.jpg "Amy E. O'Connell, MD, PhD photo")
