Role of discoidin domain receptor 1 in dysregulation of collagen remodeling by cyclosporin A.
The anti-transplant rejection drug cyclosporin A (CsA) causes loss of collagen homeostasis in rapidly remodeling connective tissues, such as human gingiva. As a result of CsA treatment, collagen degradation by fibroblasts is inhibited, which leads to a net increase of tissue collagen and gingival overgrowth. Since fibrillar collagen is the primary ligand for the discoidin domain receptor 1 (DDR1), we hypothesized that CsA perturbs DDR1-associated functions that affect collagen homeostasis. For these experiments, human fibroblasts obtained from gingival explants or mouse 3T3 fibroblasts (wild type, over-expressing DDR1 or DDR1 knockdown) or mouse GD25 cells (expressing DDR1 but null for β1 integrin), were treated with vehicle (dimethyl sulfoxide) or with CsA. The effect of CsA on cell binding to collagen was examined by flow cytometry; cell-mediated collagen remodeling was analyzed with contraction, compaction and migration assays. We found that CsA inhibited cell binding to collagen, internalization of collagen, contraction of collagen gels and cell migration over collagen in a DDR1-dependent manner. CsA also enhanced collagen compaction around cell extensions. Treatment with CsA strongly reduced surface levels of β1 integrins in wild type and DDR1 over-expressing 3T3 cells but did not affect β1 integrin activation or focal adhesion formation. We conclude that CsA inhibition of collagen remodeling is mediated through its effects on both DDR1 and cell surface levels of the β1 integrin.
Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
L A
LA
Staudinger
Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
S J
SJ
Spano
Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
W S
WS
Lee
Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
N
N
Coelho
Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
T J
TJ
Moriarty
Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5S 3E2. Electronic address: christopher.mcculloch@utoronto.ca.
C A
CA
McCulloch
D000818:Animals; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000187:drug effects / Q000378:metabolism*; D016572:Cyclosporine / Q000494:pharmacology*; D000070818:Discoidin Domain Receptors; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D011485:Protein Binding / Q000187:drug effects; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology*; D011975:Receptors, Mitogen / Q000502:physiology*
D019012:Integrin beta1; D011975:Receptors, Mitogen; D016572:Cyclosporine; D003094:Collagen; D000070818:Discoidin Domain Receptors; D020794:Receptor Protein-Tyrosine Kinases
Cell adhesion; Collagen; Extracellular matrix; Integrins; Phagocytosis