Figure 6.

Lung fibrosis is attenuated in mice receiving IPF MPCs transduced with the NLS S100A4 mutant construct. NSG mice were treated with intratracheal bleomycin (1.25 U/kg). Fourteen days later, the mice received IPF MPCs (IPF429) transduced with the S100A4 AA mutant construct, wild-type S100A4, or empty vector via tail vein injection (10⁶ cells/100 µL). There were 10 mice/group. Lungs were harvested at the end of week 6. A: collagen content was quantified in left lungs by the Sircol assay. Data are expressed as means ± SE. P values were determined by two-tailed Student’s t test. B–P: serial 4-µm sections of right lung tissue (B–G: scale bar 500 µm; H–P: scale bar 50 µm). Representative H&E and trichrome stains assessing fibrosis and collagen deposition, respectively (B–D and E–G). IHC using an antibody recognizing human procollagen to identify human cells and assess collagen synthesis (H–J) and an S100A4 antibody to assess the distribution of S100A4- and human procollagen-expressing cells (K–M). The HABP probe was used to assess HA distribution (N–P). HA, hyaluronan; HABP, hyaluronic acid-binding protein; IPF, idiopathic pulmonary fibrosis; MPCs, mesenchymal progenitor cells; NLS, nuclear localization sequence.