Effect of VCAM-1 on the Differentiation into Osteoclast

154 INTRODUCTION Tooth movement in orthodontic therapy is the result in the two events comprising bone remodeling; bone formation by osteoblasts and bone resorption by osteoclasts. Both processes are synchronized by interand intracellular signaling involving hormones, growth factors, and attachment receptors binding to the extracellular matrix (ECM). ECM is gradually increased in the pressure side and reduced in the tension side in orthodontic therapy . Integrins are transmembrane glycoproteins consisting of α and β chains, and there are eight subfamilies and there are eight subfamilies based on β-chain structure, β1 to β8. VLA-4 (very late antigen: α4β1) and VLA-5 (very late antigen: α5β1) play the most central role in the adhesion between T cells and vascular endothelial cells . The extracellular matrix protein, VCAM-1 is a member of the transmembrane immunoglobulin superfamily . Proteolytic shedding of VCAM-1 also generates a soluble form of VCAM-1 . The predominant receptor for VCAM-1 is integrin α4β1, which is expressed by many cell types of the hematopoietic lineage, including B and T lymphocytes, Effect of VCAM-1 on the Differentiation into Osteoclast