The Identification of the Progenitors of Novel, Profibrotic Epithelial Cells in 3D Culture
Idiopathic pulmonary fibrosis (IPF) is a rare chronic interstitial lung disease (ILD) whose mechanisms have not yet been elucidated. There are no current therapies to cure or halt disease progression aside from a lung transplant. To understand the mechanisms behind disease progression, IPF cells were previously sequenced via single cell technology to separate and organize cell types based on gene expression. From this preliminary data, a distinct profibrotic epithelial cell type, KRT5-/KRT17+, was discovered in large quantities in IPF lungs. KRT5-/KRT17+ cells share characteristics of both basal cells (KRT17) and fibroblasts (COL1A1). To uncover the contributions of KRT5-/KRT17+ cells to IPF symptoms, it is essential to discover the progenitor population that differentiates into KRT5-/KRT17+ cells. Although KRT5-/KRT17+ cells were originally believed to be derived from basal cells, velocity plots and differential gene analysis indicated that AT2 cells may be the progenitors of KRT5-/KRT17+ cells. Therefore, it was hypothesized that IPF AT2 cells differentiate into KRT5-/KRT17+ cells. Co-cultures with both AT2 cells and fibroblasts were developed from FACS sorted lung cells (from control and IPF lungs) to uncover KRT5-/KRT17+ cell origins. After an AT2 and fibroblast culture was stained, the presence KRT5-/KRT17+ cells was indicated. However, because both AT2 and basal cells were found in the stained organoid, the progenitor of the KRT5-/KRT17+ cells cannot be determined yet. But, it is more likely that the KRT5-/KRT17+ cells were derived from AT2 cells because organoids without AT2 markers did not yield KRT5-/KRT17+ cells. Alternative methodologies will be employed to purify future cultures to isolate AT2 cells to determine if they differentiate into KRT5-/KRT17+ cells and to uncover the nature of their behavior in IPF cultures
