Fig. 7: Upon lung injury mesothelial cells are activated into metabolically active mesothelial cells.

Upon injury, healthy mesothelial cells are activated with various upregulated metabolic processes and more active cell division. This population named “metabolically active” is characterized by the overexpression of Ifi27l2a, Crip1 and Scd1. The metabolically active state is the first stage of mesothelial cell differentiation upon injury that then gives rise to two other cell subtypes involved in the development of lung fibrosis. (i) First there are “proteolytic cells”, which overexpress proteases and are involved in the degradation of existing ECM. (ii) The second cell type are fibrogenic, with an active mesothelial to mesenchymal transition, de novo ECM deposition, and a tightened cell-ECM interaction, increased glycolytic cell decoration and immune cell invasion. Created in BioRender. Kadri, S. (2025) https://BioRender.com/k2y5xb4.