Cell Adhesion Molecule CD166/ALCAM Functions Within the Crypt to Orchestrate Murine Intestinal Stem Cell Homeostasis

Abstract

Background & AimsIntestinal epithelial homeostasis is maintained by active-cycling and slow-cycling stem cells confined within an instructive crypt-based niche. Exquisite regulating of these stem cell populations along the proliferation-to-differentiation axis maintains a homeostatic balance to prevent hyperproliferation and cancer. Although recent studies focus on how secreted ligands from mesenchymal and epithelial populations regulate intestinal stem cells (ISCs), it remains unclear what role cell adhesion plays in shaping the regulatory niche. Previously we have shown that the cell adhesion molecule and cancer stem cell marker, CD166/ALCAM (activated leukocyte cell adhesion molecule), is highly expressed by both active-cycling Lgr5+ ISCs and adjacent Paneth cells within the crypt base, supporting the hypothesis that CD166 functions to mediate ISC maintenance and signal coordination.MethodsHere we tested this hypothesis by analyzing a CD166–/– mouse combined with immunohistochemical, flow cytometry, gene expression, and enteroid culture.ResultsWe found that animals lacking CD166 expression harbored fewer active-cycling Lgr5+ ISCs. Homeostasis was maintained by expansion of the transit-amplifying compartment and not by slow-cycling Bmi1+ ISC stimulation. Loss of active-cycling ISCs was coupled with deregulated Paneth cell homeostasis, manifested as increased numbers of immature Paneth progenitors due to decreased terminal differentiation, linked to defective Wnt signaling. CD166–/– Paneth cells expressed reduced Wnt3 ligand expression and depleted nuclear β-catenin.ConclusionsThese data support a function for CD166 as an important cell adhesion molecule that shapes the signaling microenvironment by mediating ISC–niche cell interactions. Furthermore, loss of CD166 expression results in decreased ISC and Paneth cell homeostasis and an altered Wnt microenvironment.

Roles of microRNAs and RNA-Binding Proteins in the Regulation of Colorectal Cancer Stem Cells

“…A subset of CD166-positive CBCs co-express the stem cell markers, LGR5, Musashi-1(MSI1), or doublecortin-like kinase 1(DCLK1). In addition, the number of Lgr5 + stem cell is decreased and architecture of the intestinal epithelium is disrupted in the intestinal crypts of CD166 −/− mice [ 70 ]. These results suggest that CD166 is an important cell adhesion molecule for the formation and homeostasis of intestinal tissues.…”

Monoclonal Antibodies Reveal Dynamic Plasticity Between Lgr5- and Bmi1-Expressing Intestinal Cell Populations

“… 23 However, isolated Bmi1 GFP cells in the context of the same ex vivo system generate an entity distinct from the enteroid—a spheroid structure. 22 , 24 These differences in growth phenotypes motivate further investigation. The rapid and visually informative nature of cell culture makes ex vivo assays ideal for exploration of potential relations between these different cell populations and their distinct contributions to epithelial growth.…”

Porcine Esophageal Submucosal Gland Culture Model Shows Capacity for Proliferation and Differentiation

“…Similarly, the gastric stem cell marker and chief cell marker MIST1 (official gene name BHLHA15) 42 was increased in ESMG spheroids vs squamous tissue with a fold change of 2.94. Other stem cell makers that we evaluated such as the esophageal and gastric marker SOX2, the gastric cancer stem cell markers CXCR4 and CD133, 36 the intestinal crypt marker and cell adhesion molecule CD166, 43 and BMI1, FKH6, or CDX2 44 , 45 were not increased in the ESMG spheroids compared with squamous tissue. None of the evaluated stem cell markers met significance when ESMG spheroids were compared with ESMGs.…”