Endothelia of Schlemm's canal and trabecular meshwork: distinct molecular, functional, and anatomic features.
The purpose of this study was to compare human endothelial cells from Schlemm's canal (SCEs) and the trabecular meshwork (TMEs) in terms of ZO-1 isoform expression, hydraulic conductivity (HC) properties, and "giant" vacuole (GV) formation. The principal study methods were Western blot, RT-PCR, immunofluorescence, and perfusion chambers. Blot signals for alpha+ - and alpha- -isoforms were similar in SCEs but less intense for the alpha+ -relative to the alpha- -signal in TMEs. With the anti-alpha+ antibody used at 1/50 dilution, binding occurred at cell borders of both cell types, but only to SCEs when used at a >/=1/200 dilution in vitro and in vivo. SCEs were more resistive than TMEs (HC = 0.66 vs. 1.32 microl.min-1.mmHg-1.cm-2; P < 0.001) when perfused from apex to base. When perfused in the other direction, SCEs were again more resistive (5.23 vs. 9.04 microl.min-1.mmHg-1.cm-2; P < 0.01). GV formation occurred only in SCEs as a function of flow direction, perfusion pressure, and time. We conclude that SCEs and TMEs have distinctive phenotypic properties involving their content of ZO-1 isoforms, barrier function, and GV formation.
Alvarado
Jorge A
JA
Department of Ophthalmology, University of California, San Francisco, California 94143-0730, USA. jalva@itsa.ucsf.edu
Betanzos
Abigail
A
Franse-Carman
Linda
L
Chen
Janet
J
González-Mariscal
Lorenza
L
D000199:Actins / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000869:Anterior Eye Segment / Q000166:cytology* / Q000502:physiology*; D000906:Antibodies; D001082:Aqueous Humor / Q000502:physiology; D042783:Endothelial Cells / Q000502:physiology* / Q000648:ultrastructure; D015870:Gene Expression; D006801:Humans; D007365:Intercellular Junctions / Q000502:physiology; D007429:Intraocular Pressure / Q000502:physiology; D007536:Isomerism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D014129:Trabecular Meshwork / Q000166:cytology* / Q000502:physiology*; D062826:Zonula Occludens-1 Protein
D000199:Actins; D000906:Antibodies; D008565:Membrane Proteins; D010750:Phosphoproteins; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein