Figure 1. AAV9-Tert treatment targets ATII cells leading to remission of pulmonary fibrosis.

(A) Representative image of immunofluorescence against eGFP (in red) and Sftpc (in green). Mice were injected intravenously in the tail with AAV9-eGFP and sacrificed two weeks later to determine virus cell type target. The quantification of percentage of GFP⁺ Sftpc⁺ cells relative to total GFP⁺ cells and to total Sftpc⁺ cells is shown. (B) Eight-ten week old male G2Tert^-/- mice were intratracheally inoculated with 0.5 mg/kg BW bleomycin and two weeks after computed tomography (CT)-diagnosed with pulmonary fibrosis (PF). Affected mice were treated intravenously either with AAV9-empty or AAV9-Tert. Spirometric follow–up was performed at 1, 2 and 3 weeks post-viral treatment with the viral vectors. CT follow-up was performed at 1, 2, 4 and 7 weeks post-treatment with the viral vectors. Mice were sacrificed at 3 and 8 weeks post-treatment with the viral vectors for further biochemical and histopathological lung examination. (C) CT representative images for every time point of the treatment (fibrotic area in red). (D) Quantification of fold change affected lung volume with PF normalized to the affected volume before the viral treatment by computed tomography (CT). (E) Follow-up of pulmonary function measured as the ratio between lung resistance and dynamic compliance (LR/Cdyn) (F) Tert transcriptional levels in lung 8 weeks post-viral treatment. a.u., arbitrary units (G) Masson´s trichrome staining from lung sections to evaluate fibrotic regions at end point 8 weeks post-viral treatment (collagen fibers in blue; nuclei and erythrocytes in red). (H) Histopathological analysis and fibrosis score from lung sections at end point. The number of mice analyzed per group is indicated. T-test was used in D, E and F and χ² analysis in H and I for statistical analysis. *p=0.05; **p<0.01.

Figure 1—figure supplement 1. High dose of bleomycin induces pulmonary fibrosis without affecting telomere length in lung cells.

(A) Eight-ten week old wild type mice were intratracheally inoculated either with 2 mg/kg body weight bleomycin or with vehicle and sacrificed after four weeks to measure telomere length by Q-FISH in lung sections (B) Eight-ten week old wild type mice were intratracheally inoculated with 2 mg/kg body weight bleomycin and two weeks after computed tomography (CT) diagnosed with pulmonary fibrosis (PF). Affected mice were treated intravenously either with AAV9-Empty or AAV9-Tert and sacrificed after two weeks to quantify fibronectin levels by western blot. Representative Western Blot images are shown. T-test was used for statistical analysis. Error bars represent standard error. The number of mice analyzed per group is indicated. a.u.f., arbitrary units of fluorescence.