In vivo S1PR2-mediated migration control of OP monocytes visualized using intravital two-photon imaging. (A) Intravital two-photon imaging of mouse skull bone tissues of heterozygous CX₃CR1-EGFP knockin mice, in the absence (vehicle; Video 7) or presence (Video 8) of 3 mg/kg of the S1PR2 antagonist JTE013. CX₃CR1-EGFP–positive cells appear green. The microvasculature was visualized by intravenous injection of 70 kD dextran–conjugated Texas red (red; left). The movements of CX₃CR1-EGFP–positive cells were tracked for 10 min (right). Colored lines show the associated trajectories of cells. Bars, 50 µm. (B) Summary of mean velocity of CX₃CR1-EGFP–positive cells treated with JTE (red circle) or vehicle (blue square). Data points (n = 252 for vehicle and n = 237 for JTE013) represent individual cells compiled from six independent experiments, and error bars represent SD. (C) Effect of the S1PR2 antagonist JTE013 on the composition of peripheral mononuclear cells. Peripheral mononuclear cells collected from wild-type and S1PR2^−/− mice administered vehicle (C) or JTE013 (J) were stained with anti-CD3 or anti-CD11b. Absolute numbers of CD3⁺ T cells or CD11b⁺ monocytoid cells are described in the figure. Each bar represents the mean value derived from three independent experiments and error bars represent SD.