Differential expression of integrin subunits in canine knee ligament fibroblasts.
A method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side-scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the alpha5 integrin subunit; lateral collateral ligament cells stained with antibody to alpha5 showed a mean fluorescence intensity 2-fold higher than that of medial collateral ligament cells, 1.5-fold higher than that of posterior cruciate ligament cells, and 3-fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the alpha5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the beta1 integrin subunit; the expression by posterior cruciate ligament cells was 3-fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5-fold higher than that by anterior cruciate ligament cells. All cells expressed the beta3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5-fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.
Bhargava
M M
MM
Laboratory for Soft Tissue Research, Hospital for Special Surgery, Cornell University Medical Center, New York, New York, 10021, USA.
Beavis
A J
AJ
Edberg
J C
JC
Warren
R F
RF
Attia
E T
ET
Hannafin
J A
JA
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000166:cytology / Q000378:metabolism; D015703:Antigens, CD / Q000032:analysis / Q000096:biosynthesis; D004285:Dogs; D005347:Fibroblasts / Q000737:chemistry / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D039482:Integrin alpha5; D039564:Integrin alphaV; D019012:Integrin beta1 / Q000032:analysis / Q000096:biosynthesis; D016023:Integrins / Q000032:analysis / Q000096:biosynthesis*; D007717:Knee; D008023:Ligaments, Articular / Q000166:cytology* / Q000378:metabolism; D008297:Male; D017888:Medial Collateral Ligament, Knee / Q000166:cytology / Q000378:metabolism; D016119:Posterior Cruciate Ligament / Q000166:cytology / Q000378:metabolism
D015703:Antigens, CD; D039482:Integrin alpha5; D039564:Integrin alphaV; D019012:Integrin beta1; D016023:Integrins