title: Comparison of the transmembrane mucins MUC1 and MUC16 in epithelial barrier function.
abstract: Membrane-anchored mucins are present in the apical surface glycocalyx of mucosal epithelial cells, each mucosal epithelium having at least two of the mucins. The mucins have been ascribed barrier functions, but direct comparisons of their functions within the same epithelium have not been done. In an epithelial cell line that expresses the membrane-anchored mucins, MUC1 and MUC16, the mucins were independently and stably knocked down using shRNA. Barrier functions tested included dye penetrance, bacterial adherence and invasion, transepithelial resistance, tight junction formation, and apical surface size. Knockdown of MUC16 decreased all barrier functions tested, causing increased dye penetrance and bacterial invasion, decreased transepithelial resistance, surprisingly, disruption of tight junctions, and greater apical surface cell area. Knockdown of MUC1 did not decrease barrier function, in fact, barrier to dye penetrance and bacterial invasion increased significantly. These data suggest that barrier functions of membrane-anchored mucins vary in the context of other membrane mucins, and MUC16 provides a major barrier when present.
authors: Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors: Ilene K
authors: IK
authors: Gipson
authors: Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors: Sandra
authors: S
authors: Spurr-Michaud
authors: Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors: Ann
authors: A
authors: Tisdale
authors: Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors: Balaraj B
authors: BB
authors: Menon
mesh_terms: D001422:Bacterial Adhesion; D018394:CA-125 Antigen / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D004396:Coloring Agents / Q000378:metabolism; D017097:Electric Impedance; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism* / Q000382:microbiology; D055785:Gene Knockdown Techniques; D006801:Humans; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018396:Mucin-1 / Q000235:genetics / Q000378:metabolism*; D009092:Mucous Membrane / Q000166:cytology; D019108:Tight Junctions / Q000378:metabolism
chemical_list: D018394:CA-125 Antigen; D004396:Coloring Agents; C451759:MUC16 protein, human; D008565:Membrane Proteins; D018396:Mucin-1