Hardie Lab

Lung biopsy from a patient with severe cystic fibrosis lung disease taken at the time of lung transplantation. There is severe lung fibrosis extending out from the diseased airway extending into the alveolar areas of the lung. An airway has been obliterated from the chronic infection and inflammation and replaced with mesenchymal and inflammatory cells and extracellular matrix (arrow).

Schemata (left) demonstrating genetic construct of transgenic mice overexpressing Transforming Growth Factor-α (TGFa) which is overexpressed in airway and Type II epithelium only when mice are administered doxycycline (Dox). Pentachrome stain (right) demonstrating fibrosis is detected in adventitial regions of lung and progresses in the absence of detectable inflammation.

Trichrome stain from mice overexpressing TGFa for 8 weeks demonstrating extensive adventitial (top) and pleural (bottom) fibrosis.

Hematoxylin and eosin stain of lung biopsy from a patients with idiopathic pulmonary fibrosis (IPF, left) and TGFα transgenic mice following 6 weeks of Dox (right). Fibrosis in IPF and TGFα mice extends inward from pleural surface (top panels). Lower panels demonstrate focal areas of fibroblasts expansion in lung parenchyma.

Cell signaling pathways activated downstream of TGFα/Epidermal Growth Factor Receptor (EGFR) which mediate fibroproliferation. Sites of specific pathway inhibition with pharmacologic inhibitors or genetic knockout mice are indicated that the laboratory is in the process of studying.

Smooth muscle actin stain on lung sections from mice overexpressing TGFa for 4 weeks demonstrating extensive pleural fibrosis (middle panel) which is inhibited when mice are pre-treated with the PI3K inhibitor PX-866.

To assess the efficacy of PI3K inhibition in established fibrosis, TGFa transgenic mice were treated with the PI3K inhibitor PX-866 after 4 weeks of Dox while remaining on Dox for an additional 4 weeks. Controls were treated with vehicle while remaining on Dox an additional 4 weeks. Dox induced expression of TGFa for 8 weeks caused progressive weight loss in vehicle-treated mice (red line), while mice treated with PX-866 4 weeks after TGFa induction did not have changes in body weight (green line), but weights remained below CCSP/- controls (blue line), and CCSP/TGFa mice which received 4 weeks of Dox, then taken Off Dox and treated with 4 weeks of vehicle (gold line).

Hematoxylin and eosin stain on lung sections from mice overexpressing TGFa for 7 weeks demonstrating extensive pleural fibrosis (middle panel) which is inhibited when mice are pre-treated with the mTOR inhibitor Rapamycin.

Representative photomicrographs of lung plural regions from TGFα mice stained for α smooth muscle actin (aSMA, green) and phosphorylated ERK1/2 (pERK, Red). Overlaid and enlarged images show a co-localization of signals for pERK1/2 with aSMA positive cells, indicating that pERK-positive cells were mesenchymal cells.

Control (A) and TGFα (B) mice were irradiated and reconstituted with green florescent protein (GFP) bone marrow cells. Lung cryosections from fibrotic regions following 4 wks Dox show GFP+ bone marrow derived cells accumulate in the lungs of TGFα mice but not in CCSP/- mice.