CD44v3-positive Intermediate Progenitor Cells Contribute to Airway Goblet Cell Hyperplasia.

In allergic airway diseases, intermediate progenitor cells (IPCs) increase in number in the surface epithelium. IPCs arise from basal cells, the origin of hallmark pathological changes, including goblet cell hyperplasia and mucus hypersecretion. Thus, targeting IPCs will benefit future treatment of allergic airway diseases. However, the lack of adequate cell surface markers for IPCs limits their identification and characterization. We now show that CD44 containing exon v3 (CD44v3) is a surface marker for IPCs that are capable of both proliferating and generating differentiated goblet cells in allergic human nasal epithelium. In primary human nasal epithelial (HNE) cells that had differentiated at an air-liquid interface, interleukin-4 (IL-4) upregulated mRNA expression of three CD44v variants that include exon v3 (CD44v3-v6, CD44v3,v8-v10, and CD44v3-v10), and induced expression of CD44v3 protein in the basal and supra-basal layers of the culture. Fluorescence-activated cell sorting (FACS) analysis revealed two subpopulations differing in CD44v3 levels: CD44v3low cells expressed high levels of proliferative and basal cell markers (Ki-67 and p63), whereas CD44v3high cells strongly expressed progenitor and immature/mature goblet cell markers (SOX2, CA2, and SPDEF). Importantly, a blocking anti-CD44 antibody suppressed IL-4-induced mucin production by HNE cells. Furthermore, CD44v3 was co-expressed with p63, KRT5, or SOX2, and was upregulated in the basal and supra-basal layers of the nasal surface epithelium of allergic rhinitis (AR) subjects. Taken together, these data demonstrate that high CD44v3 expression contributes to goblet cell hyperplasia in inflammation of the allergic airway.