IADR Abstract Archives
MUC1, INADL and SCRIB Identify Ductal Cells in Salivary Glands
Objectives: Among other characteristics, salivary acinar cells differ from ductal cells in that they: 1) are highly secretory and produce large amounts of saliva, and 2) have a pyramidal morphology that differs from cylindrical ductal cells. For tissue engineering of complex glandular structures from human stem/progenitor cells (hS/PCs), it is essential to distinguish these two epithelial populations. We hypothesized that the polarity complexes in acinar and ductal cells in the salivary gland would express distinct polarity complex proteins. We examined polarity complexes and the apical marker MUC1 in human salivary glands and hS/PCs with the objective to determine if these can serve as lineage biomarkers.
Methods: The establishment and maintenance of cellular polarity involves three protein complexes: 1) Crumbs, 2) Partition, and 3) Scribble. We used immunodetection, quantitative RT-PCR, laser capture microdissection and in situ hybridization to examine three distinct polarity complexes potentially present in acinar and ductal epithelial cells in salivary glands. We examined both normal primary salivary tissue (parotid, submandibular) from surgical specimens and from human stem/progenitor cells (hS/PCs) obtained from explants expanded ex vivo, then cultured under differentiating conditions.
Results: We found that polarity complexes in acinar and ductal cells have both common and distinct features. The Partition Complex represented by PAR3 was present in both acinar and ductal cells and was not distinguishing. SCRIB was present almost exclusively in ducts, as was the apical Crumbs Complex represented by INADL. The apical transmembrane mucin MUC1 also identified ductal cells.
Conclusions: Polarized salivary ductal cells contain all three “classic” polarity complexes, as well as apical MUC1, and can be identified by their presence. Acinar cells have distinct complexes in which the Partition Complex predominates. We conclude that polarity complex proteins INADL and SCRIB, along with MUC1, can identify ductal cells in tissue and in differentiating hS/PCs.
Methods: The establishment and maintenance of cellular polarity involves three protein complexes: 1) Crumbs, 2) Partition, and 3) Scribble. We used immunodetection, quantitative RT-PCR, laser capture microdissection and in situ hybridization to examine three distinct polarity complexes potentially present in acinar and ductal epithelial cells in salivary glands. We examined both normal primary salivary tissue (parotid, submandibular) from surgical specimens and from human stem/progenitor cells (hS/PCs) obtained from explants expanded ex vivo, then cultured under differentiating conditions.
Results: We found that polarity complexes in acinar and ductal cells have both common and distinct features. The Partition Complex represented by PAR3 was present in both acinar and ductal cells and was not distinguishing. SCRIB was present almost exclusively in ducts, as was the apical Crumbs Complex represented by INADL. The apical transmembrane mucin MUC1 also identified ductal cells.
Conclusions: Polarized salivary ductal cells contain all three “classic” polarity complexes, as well as apical MUC1, and can be identified by their presence. Acinar cells have distinct complexes in which the Partition Complex predominates. We conclude that polarity complex proteins INADL and SCRIB, along with MUC1, can identify ductal cells in tissue and in differentiating hS/PCs.