Figure 6
FTY720 recruits non-classical monocytes and CD206+ macrophages to perivascular niches in inflamed tissue. (a) Intravital imaging of DWCs in CX3CR1GFP/+ transgenic mice 1 day post-injury. CX3CR1hi cells preferentially accumulated around peri-implant arterioles (white arrows) (b) Representative surface renderings of CX3CR1+ cells, color-coded according to distance from the closest blood vessel with red cells being closest to blood vessels and purple cells being the farthest away. Vessels were labeled with i.v. injection of rhodamine-dextran. (c) Distance to the nearest blood vessels of CX3CR1hi cells in animals treated with FTY720 compared to unloaded PLGA controls. (d) Distance to the nearest blood vessels of CX3CR1lo cells. Statistical analyses were conducted using two-tailed Mann-Whitney test. *p < 0.05, n > 100 cells, across 3–4 animals per group. (e) Immunostaining of CD68+CD206+ macrophages and vasculature. In animals treated with unloaded PLGA, perivascular CD68+CD206+ macrophages were circular (open arrow), while in FTY720-treated animals, CD68+CD206+ macrophages associated closely with inflamed vasculature and adopted an elongated morphology (solid white arrows, identified by aspect ratio greater than 2). Scale bars, 100 µm.
