Probes for INS

The epithelial lining of the Fallopian tube is vital for fertility, providing nutrition to gametes, and facilitating their transport. It is composed of two major cell types: secretory cells and ciliated cells. Interestingly, human ovarian cancer precursor lesions are primarily consisting of secretory cells. It is unclear why secretory cells are the dominant cell type in these lesions. Additionally, the underlying mechanisms governing Fallopian tube epithelial homoeostasis are currently unknown. In the present study, we showed that across the different developmental stages of mouse oviduct, secretory cells are the most frequently dividing cells of the oviductal epithelium. In vivo genetic cell lineage tracing showed that secretory cells not only self-renew, but also give rise to ciliated cells. Analysis of a Wnt reporter mouse model and different Wnt target genes showed that the Wnt signaling pathway is involved in oviductal epithelial homoeostasis. By developing two triple transgenic mouse models, we showed that Wnt/β-catenin signaling is essential for self-renewal as well as differentiation of secretory cells. In summary, our results provide mechanistic insight into oviductal epithelial homoeostasis.

Intestinal mesenchymal cells play essential roles in epithelial homeostasis, matrix remodeling, immunity, and inflammation. But the extent of heterogeneity within the colonic mesenchyme in these processes remains unknown. Using unbiased single-cell profiling of over 16,500 colonic mesenchymal cells, we reveal four subsets of fibroblasts expressing divergent transcriptional regulators and functional pathways, in addition to pericytes and myofibroblasts. We identified a niche population located in proximity to epithelial crypts expressing SOX6, F3 (CD142), and WNT genes essential for colonic epithelial stem cellfunction. In colitis, we observed dysregulation of this niche and emergence of an activated mesenchymal population. This subset expressed TNF superfamily member 14 (TNFSF14), fibroblastic reticular cell-associated genes, IL-33, and Lysyl oxidases. Further, it induced factors that impaired epithelial proliferation and maturation and contributed to oxidative stress and disease severity in vivo. Our work defines how the colonic mesenchyme remodels to fuel inflammation and barrier dysfunction in IBD.

How stem cells maintain their identity and potency as tissues change during growth is not well understood. In mammalian hair, it is unclear how hair follicle stem cells can enter an extended period of quiescence during the resting phase but retain stem cell potential and be subsequently activated for growth. Here, we use lineage tracing and gene expression mapping to show that the Wnt target gene Axin2 is constantly expressed throughout the hair cycle quiescent phase in outer bulge stem cells that produce their own Wnt signals. Ablating Wnt signaling in the bulge cells causes them to lose their stem cell potency to contribute to hair growth and undergo premature differentiation instead. Bulge cells express secreted Wnt inhibitors, including Dickkopf (Dkk) and secreted frizzled-related protein 1 (Sfrp1). However, the Dickkopf 3 (Dkk3) protein becomes localized to the Wnt-inactive inner bulge that contains differentiated cells. We find that Axin2 expression remains confined to the outer bulge, whereas Dkk3 continues to be localized to the inner bulge during the hair cycle growth phase. Our data suggest that autocrine Wnt signaling in the outer bulge maintains stem cell potency throughout hair cycle quiescence and growth, whereas paracrine Wnt inhibition of inner bulge cells reinforces differentiation.

Interleukin 10 receptor (IL10R)-deficient mice develop spontaneous colitis and, similarly, patients with loss-of-function mutations in IL10R develop severe infant-onset inflammatory bowel disease. Loss of IL10R signaling in mouse and human macrophages is associated with increased production of interleukin 1β. We demonstrated that innate immune production of IL1β mediates colitis in IL10R-deficient mice. Transfer of Il1r1-/- CD4+ T cells into Rag1-/-/Il10rb-/- mice reduced the severity of their colitis (compared to mice that received CD4+ T cells that express IL1R), accompanied by decreased production of interferon gamma, tumor necrosis factor-α, and IL17A. In macrophages from mice without disruption of IL10R signaling or from healthy humans (controls), incubation with IL10 reduced canonical activation of the inflammasome and production of IL1β through transcriptional and post-translational regulation of NLRP3. Lipopolysaccharide and adenosine triphosphate stimulation of macrophages from Il10rb-/- mice or IL10R-deficient patients resulted in increased production of IL1β. Moreover, in human IL10R-deficient macrophages, lipopolysaccharide stimulation alone triggered IL1β secretion via non-canonical, caspase 8-dependent activation of the inflammasome. We treated 2 IL10R-deficient patients with severe and treatment-refractory infant-onset inflammatory bowel disease with the IL1-receptor antagonist anakinra. Both patients had marked clinical, endoscopic, and histologic responses after 4-7 weeks. This treatment served as successful bridge to allogeneic hematopoietic stem cell transplantation in 1 patient. Our findings indicate that loss of IL10 signaling leads to intestinal inflammation, at least in part, through increased production of IL1 by innate immune cells, leading to activation of CD4+ T cells. Agents that block IL1 signaling might be used to treat patients with inflammatory bowel disease resulting from IL10R deficiency.

Abstract

BACKGROUND:

Large animal models, such as the dog, are increasingly being used for studying diseases including gastrointestinal (GI) disorders. Dogs share similar environmental, genomic, anatomical, and intestinal physiologic features with humans. To bridge the gap between commonly used animal models, such as rodents, and humans, and expand the translational potential of the dog model, we developed a three-dimensional (3D) canine GI organoid (enteroid and colonoid) system. Organoids have recently gained interest in translational research as this model system better recapitulates the physiological and molecular features of the tissue environment in comparison with two-dimensional cultures.

RESULTS:

Organoids were derived from tissue of more than 40 healthy dogs and dogs with GI conditions, including inflammatory bowel disease (IBD) and intestinal carcinomas. Adult intestinal stem cells (ISC) were isolated from whole jejunal tissue as well as endoscopically obtained duodenal, ileal, and colonic biopsy samples using an optimized culture protocol. Intestinal organoids were comprehensively characterized using histology, immunohistochemistry, RNA in situ hybridization, and transmission electron microscopy, to determine the extent to which they recapitulated the in vivo tissue characteristics. Physiological relevance of the enteroid system was defined using functional assays such as optical metabolic imaging (OMI), the cystic fibrosis transmembrane conductance regulator (CFTR) function assay, and Exosome-Like Vesicles (EV) uptake assay, as a basis for wider applications of this technology in basic, preclinical and translational GI research. We have furthermore created a collection of cryopreserved organoids to facilitate future research.

CONCLUSIONS:

We establish the canine GI organoid systems as a model to study naturally occurring intestinal diseases in dogs and humans, and that can be used for toxicology studies, for analysis of host-pathogen interactions, and for other translational applications.