Lineage-traced RPTCs showed no increase in the expression of the mesenchymal protein α-smooth muscle actin (αSMA) or downregulation of the epithelial marker Zona occludens-1 (ZO-1), indicating that diabetes was not associated with epithelial-mesenchymal transition of RPTCs (Figures S3A and S3B). Here, TJP1 is linked to diabetes mellitus.