MCP/CCR2 signaling is essential for recruitment of mesenchymal progenitor cells during the early phase of fracture healing

• Published in: PloS one 2014-08, Vol.9 (8), p.e104954-e104954
• Main Authors: Ishikawa, Masahiro, Ito, Hiromu, Kitaori, Toshiyuki, Murata, Koichi, Shibuya, Hideyuki, Furu, Moritoshi, Yoshitomi, Hiroyuki, Fujii, Takayuki, Yamamoto, Koji, Matsuda, Shuichi
• Format: Article
• Language: English
• Subjects: Analysis; Animal models; Animals; Biology and Life Sciences; Bone growth; Bone healing; Bone marrow; CC chemokine receptors; CCR2 protein; Cells (biology); Cells, Cultured; Chemokine CCL2 - genetics; Chemokine CCL2 - metabolism; Chemokines; Computed tomography; Cytokines; Fracture Healing; Fractures; Fractures (Injuries); Grafting; Grafts; Growth factors; Healing; Inflammation; Medicine; Medicine and Health Sciences; Mesenchymal Stromal Cells - cytology; Mesenchyme; Mice; Mice, Knockout; Monocyte chemoattractant protein 1; Monocyte chemoattractant protein 3; Mouse devices; Musculoskeletal system; Osteogenesis; Periosteum; Polymerase chain reaction; Progenitor cells; Real-Time Polymerase Chain Reaction; Receptors, CCR2 - genetics; Receptors, CCR2 - metabolism; Recruitment; Rheumatic diseases; Signal Transduction - genetics; Signal Transduction - physiology; Signaling; Staining; Stem cells; Stromal cells; Substitute bone; Surgery; Transplantation; University graduates
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0104954

The purpose of this study was to investigate chemokine profiles and their functional roles in the early phase of fracture healing in mouse models. The expression profiles of chemokines were examined during fracture healing in wild-type (WT) mice using a polymerase chain reaction array and histological staining. The functional effect of monocyte chemotactic protein-1 (MCP-1) on primary mouse bone marrow stromal cells (mBMSCs) was evaluated using an in vitro migration assay. MCP-1-/- and C-C chemokine receptor 2 (CCR2)-/- mice were fractured and evaluated by histological staining and micro-computed tomography (micro-CT). RS102895, an antagonist of CCR2, was continuously administered in WT mice before or after rib fracture and evaluated by histological staining and micro-CT. Bone graft exchange models were created in WT and MCP-1-/- mice and were evaluated by histological staining and micro-CT. MCP-1 and MCP-3 expression in the early phase of fracture healing were up-regulated, and high levels of MCP-1 and MCP-3 protein expression observed in the periosteum and endosteum in the same period. MCP-1, but not MCP-3, increased migration of mBMSCs in a dose-dependent manner. Fracture healing in MCP-1-/- and CCR2-/- mice was delayed compared with WT mice on day 21. Administration of RS102895 in the early, but not in the late phase, caused delayed fracture healing. Transplantation of WT-derived graft into host MCP-1-/- mice significantly increased new bone formation in the bone graft exchange models. Furthermore, marked induction of MCP-1 expression in the periosteum and endosteum was observed around the WT-derived graft in the host MCP-1-/- mouse. Conversely, transplantation of MCP-1-/- mouse-derived grafts into host WT mice markedly decreased new bone formation. MCP-1/CCR2 signaling in the periosteum and endosteum is essential for the recruitment of mesenchymal progenitor cells in the early phase of fracture healing.