Figure 4.

GRK2-dependent CXCR2 downregulation promotes neutrophil rTEM in aged tissues.

(A–F) Young and aged mice were treated i.s. with IL-1β.

(A) Representative confocal images of cremasteric post-capillary venules (PCVs) of WT mice immunostained for CXCR2, MRP14 (neutrophils) and CD31. Arrows indicate CXCR2^lo neutrophils (scale bar: 10 μm; dashed boxes delineate magnified areas).

(B) Percentage of luminal CXCR2^lo neutrophils in cremasteric PCVs of EC Ackr1^+/+ and EC Ackr1^−/− chimeras (n = 3-5 mice/group).

(C) Generation of neutrophil Grk2^+/+ and Grk2^−/− chimeras.

(D–F) Young and aged chimeras as generated in (C) were treated i.s. with IL-1β.

(D) Percentage of luminal CXCR2^lo neutrophils (n = 3-4 mice/group).

(E) Total neutrophil TEM events and (F) frequency of neutrophil rTEM as assessed by confocal IVM (n = 3-4 mice/group). Means ± SEM #p < 0.05, ####p < 0.0001 as compared to young, ^∗p < 0.05, ^∗∗∗p < 0.001 as indicated.

See also Figure S4.