Adhesion of human trabecular meshwork cells to extracellular matrix proteins. Roles and distribution of integrin receptors.
OBJECTIVE
To examine the adhesion of human trabecular meshwork cells with various extracellular matrix (ECM) proteins and to evaluate the roles and distribution of integrin receptors.


METHODS
Cultured human trabecular meshwork cells were added to 96-well plates either uncoated or coated with proteins including fibronectin, laminin, and vitronectin, as well as collagen types I, III, IV, V, and VI. After incubation for 1 hour, the adhesion of cells was measured. Expression of cell surface integrins was determined by cell enzyme-linked immunoadsorbent assay (ELISA) and immunoprecipitation. Distribution was visualized by immunofluorescence staining using integrin-specific antibodies. For function perturbation and peptide inhibition studies, cells were preincubated with either integrin antibodies or synthetic peptides before the adhesion assays.


RESULTS
Human trabecular meshwork cells attached to plates coated with ECM proteins in a dose-dependent manner. Fibronectin, vitronectin, and collagen types I and IV were the preferred ECM substrates. Cell ELISA revealed the presence of integrins alpha 1, alpha 2, alpha 3, alpha 4, alpha 5, alpha 6, alpha v, beta 1, beta 3, beta 5, alpha 5 beta 1, and alpha v beta 3 and the absence of beta 2 and beta 4 on human trabecular meshwork cells. Results from immunostaining experiments were consistent with those from cell ELISA studies. Attachment of cells to ECM proteins was blocked by specific integrin antibodies. Cell adhesion to fibronectin and vitronectin was inhibited by peptides containing the Arg-Gly-Asp sequence.


CONCLUSIONS
Extracellular matrix proteins mediate the adhesion of human trabecular meshwork cells in culture. Integrin receptors appear to have functional roles in the cell-matrix interactions.
Department of Ophthalmology and Visual Sciences, College of Medicine, University of Illinois at Chicago 60612, USA.
L
L
Zhou
S R
SR
Zhang
B Y
BY
Yue
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D002448:Cell Adhesion; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D016023:Integrins / Q000502:physiology*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism; D011233:Precipitin Tests; D014129:Trabecular Meshwork / Q000166:cytology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D016326:Extracellular Matrix Proteins; D016023:Integrins; D009842:Oligopeptides