title: Urothelial injuries and the early wound healing response: tight junctions and urothelial cytodifferentiation.
abstract: Using primary explant cultures of mouse bladder, the early response of the urothelium after superficial and full-thickness injuries was investigated. In such an in vitro wound healing model, explant surfaces with a mostly desquamated urothelial superficial layer represented superficial wounds, and the exposed lamina propria at the cut edges of the explants represented full-thickness wounds. The urothelial cell ultrastructure, the expression and subcellular distribution of the tight junctional protein occludin, and differentiation-related proteins CK 20, uroplakins, and actin were followed. Since singular terminally differentiated superficial cells remained on the urothelium after superficial injury (i.e., original superficial cells), we sought to determine their role during the urothelial wound-healing process. Ultrastructural and immunocytochemical studies have revealed that restored tight junctions are the earliest cellular event during the urothelial superficial and full-thickness wound-healing process. Occludin-containing tight junctions are developed before the new superficial cells are terminally differentiated. New insights into the urothelium wound-healing process were provided by demonstrating that the original superficial cells contribute to the urothelium wound healing by developing tight junctions with de novo differentiated superficial cells and by stretching, thus providing a large urothelial surface with asymmetric unit membrane plaques.
authors.affiliation: Institute of Cell Biology, Medical Faculty, University of Ljubljana, Lipiceva 2, 1000 Ljubljana, Slovenia. mateja.erdani@mf.uni-lj.si
authors.forename: Mateja Erdani
authors.initials: ME
authors.lastname: Kreft
authors.forename: Maksimiljan
authors.initials: M
authors.lastname: Sterle
authors.forename: Peter
authors.initials: P
authors.lastname: Veranic
authors.forename: Kristijan
authors.initials: K
authors.lastname: Jezernik
mesh_terms: D000199:Actins / Q000032:analysis; D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D019084:Fluorescent Antibody Technique, Indirect; D007381:Intermediate Filament Proteins / Q000032:analysis; D053554:Keratin-20; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D051379:Mice; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008938:Mitosis; D062793:Occludin; D059470:Tetraspanins; D019108:Tight Junctions / Q000737:chemistry / Q000502:physiology; D046509:Tissue Culture Techniques; D014404:Tubulin / Q000032:analysis; D001743:Urinary Bladder / Q000737:chemistry / Q000293:injuries / Q000503:physiopathology*; D060170:Uroplakin II; D060171:Uroplakin III; D060167:Uroplakin Ia; D060169:Uroplakin Ib; D019459:Urothelium / Q000293:injuries / Q000503:physiopathology* / Q000648:ultrastructure; D014746:Vimentin / Q000032:analysis; D014945:Wound Healing
chemical_list: D000199:Actins; D007381:Intermediate Filament Proteins; D053554:Keratin-20; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D062793:Occludin; C568986:Ocln protein, mouse; D059470:Tetraspanins; D014404:Tubulin; C490123:Upk1a protein, mouse; C490124:Upk1b protein, mouse; C554659:Upk2 protein, mouse; D060170:Uroplakin II; D060171:Uroplakin III; D060167:Uroplakin Ia; D060169:Uroplakin Ib; D014746:Vimentin