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. Author manuscript; available in PMC: 2021 Sep 6.
Published in final edited form as: Adv Exp Med Biol. 2019;1169:95–117. doi: 10.1007/978-3-030-24108-7_6

Fig. 6.5.

Fig. 6.5

Nuances among pulmonary secretory cells. Recent studies have provided compelling data for anatomical specificity of secretory cell types in the human lung. (a) Based on the expression of MUC5B, MUC5AC, and SCGB1A1 (CCSP), there are at least four distinct secretory cell types. Submucosal glands possess MUC5B-expressing secretory mucous cells. In proximal large airways, secretory club-like cells express MUC5B, MUC5AC, and SCGB1A1. In small bronchial airways, secretory club-like cells express MUC5B and SCGB1A1 but not MUC5AC, and in terminal bronchioles, secretory club-like cells express only SCGB1A1 [14]. (b) Given that club-like cells express many of the phenotypic characteristic of goblet cells, it may be necessary to experimentally challenge the paradigm that goblet cells are indeed a divergent cell type rather than simply being a hypersecretory state of club-like cells. For example, if goblet cell metaplasia/hyperplasia is readily reversible back to a club-like cell phenotype, this may suggest that goblet cells and club-like cells are the same population of secretory cells