Author/Editor     Višnjar, Tanja; Kocbek, Petra; Erdani-Kreft, Mateja
Title     Hyperplasia as a mechanism for rapid resealing urothelial injuries and maintaining high transepithelial resistance
Type     članek
Source     Histochem Cell Biol
Vol. and No.     Letnik 137, št. 2
Publication year     2012
Volume     str. 177-86
Language     eng
Abstract     When the urothelial barrier, i.e., the blood-urine barrier, is injured, rapid resealing of the injury is crucial for the normal functioning of the organism. In order to investigate the mechanisms required for rapid resealing of the barrier, we established in vitro models of hyperplastic and normoplastic urothelia. We found that hyperplastic urothelia achieve significantly higher transepithelial resistance (TER) than normoplastic urothelia. However, the expression of cell junctional (claudin-8, occludin, E-cadherin) and differentiation-related proteins (cytokeratin 20 and uroplakins) is weaker in hyperplastic urothelia. Further investigation of cell differentiation status at the ultrastructural level confirmed that superficial urothelial cells (UCs) in hyperplastic urothelial models achieve a lower differentiation stage than superficial UCs in normoplastic urothelial models. With the establishment of such in vitro models and the aid of TER measurements, flow cytometry, molecular and ultrastructural analysis, we here provide unequivocal evidence that the specific cell-cycle distribution and, consequently, the number of cell layers have a significant influence on the barrier function of urothelia. We demonstrate the importance of hyperplasia for the rapid restoration of the urothelial barrier and the maintenance of high TER until the UCs reach a highly differentiated stage and restoration of the urothelial barrier after injury is complete. The information that this approach provides is unique and we expect that further exploitation of hyperplastic and normoplastic urothelial models in future studies may advance our understanding of blood-urine barrier development and functionality.
Descriptors     UROTHELIUM
HYPERPLASIA
INTERCELLULAR JUNCTIONS
KERATIN
CELL MEMBRANE PERMEABILITY
WOUND HEALING
CELLS, CULTURED
CELL CYCLE PROTEINS
FLOW CYTOMETRY
FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT
MICROSCOPY, ELECTRON, SCANNING TRANSMISSION