Proteomic and phosphoproteomic profiling of SFTPCI73T expressing patient-specific pluripotent stem cell-derived alveolar epithelial type 2 cells and their gene-edited corrected counterparts.

We performed proteomic and phosphoproteomic profiling of cells derived from human induced pluripotent stem cells (iPSCs) using our previously described distal lung directed differentiation protocol to generate alveolar epithelial type 2 cells (iAEC2s). We used the SPC2 human iPSC line and specifically the SPC2-ST-B2 (SFTPCtdT/WT) and SPC2-ST-C11 (SFTPCI73T/tdT) clones containing a SFTPCtdTomato knock-in reporter. SFTPCtdTomato+ cells were sorted on day 41 and again on day 79 of differentiation. iAEC2s were single-cell passaged in self-renewing 3D alveolosphere cultures approximately every 2 weeks through day 113. Live SFTPCtdTomato+ iAEC2s were sorted on day 113 and processed for mass spectrometry. We find that mutant (SFTPCI73T/tdT) iAEC2s display a less proliferative and more mature AEC2 phenotype compared to their corrected (SFTPCtdT/WT) counterparts with a concomitant upregulation of lysosomal and autophagy related pathways and activation of the NF-κB pathway in mutant cells.