ED Figure 6. Hedgehog modulates mesenchymal response to bleomycin injury.

Chronic repetitive injury to the lung epithelium with bleomycin over 4 weeks down-regulates Gli1 expression in the mesenchyme adjacent to the airways in Gli1^lacZ lungs as noted by histochemical staining for β-galactosidase activity (a–d) and as noted using X-gal quantification and Q-PCR analysis of Shh and Gli1 expression after four weeks of repetitive injury (e, n=2 animals per group). Lineage-traced, Gli1+ Hh activated lung mesenchymal cells undergo proliferative expansion after repetitive bleomycin injury with an increase in Ki67+ mesenchymal cells (f–i,n, n=4 animals per group). Expression of Smo^M2 within lineage traced Gli1+ lung mesenchymal cells attenuates the proliferative expansion that normally follows repetitive bleomycin injury (j–m,o, n=3 animals per group). Gli1 expression remain reduced 2 months after the end of bleomycin treatment (p–r, n=2 animals per group), which might be due to the persistent scarring that is observed after repetitive bleomycin injury (s–v). AW= airway, V=blood vessel, Scale bars= 100 microns, * p<0.05.