Fig. 4

Pericyte migration is mediated via the CXCL12/CXCR4 pathway. Female C57/Bl6 mice (6–8 weeks old) were subjected to intranasal delivery of sterile PBS (10 µl) or house dust mite extract (HDM; 25 µg in 10 µl) 5 days a week for 5 consecutive weeks. A At the end of the protocol, the lungs were removed and pericytes were assessed by flow cytomtry to determine the median fluorescence intensity of CXCR4 using FlowJo software. n = 14 representative of three independent experiments; * p < 0.05. B) Bronchoalveolar fluid from PBS control mice and mice exposed to HDM for either 3 weeks or 5 weeks was submitted to ELISA to assess levels of CXCL12. n = 7–8 per group from two independent experiments; **p < 0.01. C Healthy human pericytes were treated with TGF-β in vitro (10 ng/ml for 7 days) and subjected to Transwell assays using fetal calf serum (FCS) or CXCL12 (300 ng/well) as the chemoattractant. n = 8–10 per group, representative of three independent experiments; ***p < 0.001. D Lung sections obtained from PBS control and HDM-exposed mice were stained for the pericyte marker NG2 (green), the mesenchymal cell marker α-smooth muscle actin (α-SMA; red) and CXCR4 (cyan) to assess the infiltration of CXCR4+ pericytes into airway smooth muscle bundles (white arrows). Scale bar 25 µm. AW: airway; BV: blood vessel; HDM: house dust mite; LIT: LIT-927 (CXCL12 neutraligand); PBS: phosphate-buffered saline; VEH: vehicle control