title: Activated protein C mediates a healing phenotype in cultured tenocytes.
abstract: Tendon injuries cause considerable morbidity in the general adult population. The tenocytes within the tendon have the full capacity to heal the tendon intrinsically. Activated protein C (APC) plays an important role in coagulation and inflammation and more recently has been shown to promote cutaneous wound healing. In this study we examined whether APC can induce a wound healing phenotype in tenocytes. Sheep tenocytes were treated with APC, endothelial protein C receptor (EPCR) blocking antibody (RCR252) and/or EPCR small interfering (si)RNA. Cell proliferation and migration were measured by crystal violet assay and a scratch wounding assay, respectively. The expression of EPCR, matrix metalloproteinase (MMP)-2, type I collagen and MAP kinase activity were detected by real time PCR, zymography, immunofluorescence, immunohistochemistry and Western blotting. APC stimulated proliferation, MMP-2 activity and type I collagen deposition in a dose-dependent manner and promoted migration of cultured tenocytes. APC dose-dependently stimulated phosphorylated (P)-ERK2 and inhibited P-p38. Interestingly, tenocytes expressed EPCR protein, which was up-regulated by APC. When tenocytes were pre-treated with RCR252 or EPCR siRNA the effect of APC on proliferation, MMP-2 and type 1 collagen synthesis and MAP kinases was blocked. APC promotes the growth, MMP-2 activity, type I collagen deposition and migration of tenocytes. Furthermore, EPCR is expressed by tenocytes and mediates the actions of APC, at least partly by signalling through selective MAP kinases. These data implicate APC as a potential healing agent for injured tendons.
authors.affiliation: Institute of Bone and Joint Research, Kolling Institute of Medical Research, The University of Sydney at Royal North Shore Hospital, St. Leonards, NSW, Australia.
authors.forename: Meilang
authors.initials: M
authors.lastname: Xue
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Smith
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Little
authors.forename: Philip
authors.initials: P
authors.lastname: Sambrook
authors.forename: Lyn
authors.initials: L
authors.lastname: March
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Jackson
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis; D000074283:Endothelial Protein C Receptor; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010641:Phenotype; D011486:Protein C / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D012756:Sheep; D013710:Tendons / Q000166:cytology* / Q000201:enzymology; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D015703:Antigens, CD; D024042:Collagen Type I; D000074283:Endothelial Protein C Receptor; C478370:PROCR protein, human; D011486:Protein C; D011956:Receptors, Cell Surface; D020928:Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2