Figure 9.

The majority of tdTomato⁺PECs co-express PAX8 along Bowman’s capsule, however newly generated podocytes from PEC origin no longer express PAX8. Activated PECs (tdTomato⁺CD44⁺) were detected in the glomerular tuft of aged mice. (A, B) Representative confocal images of tdTomato⁺ (red), EGFP⁺ (green) and CD44⁺ (blue) in young and aged mice. The inserts show separate channels of the outlined glomeruli, with superscripts: 1=tdTomato, 2=EGFP, 3=CD44 and 4=merged. (A) Young mice showed that CD44 staining was not detected in the glomerular tuft. An occasional CD44⁺ cell was observed around glomeruli (marked with arrow heads). Each channel for the glomerular tuft region marked with the dashed box are presented in panels (A¹–A⁴). (B) Aged mice showed that a subpopulation of tdTomato⁺PECs (B¹) that migrated to glomerular tuft were positive for CD44 (magenta color, B³- B⁴), marked with dashed arrows, with no overlap with EGFP (B²). (C, D) Representative confocal images of tdTomato⁺ (red), EGFP⁺ (green) and PAX8 (blue) in young and aged mice. The inserts show separate channels of the outlined glomeruli, with superscripts: 1=tdTomato, 2=EGFP, 3=PAX8 and 4=merged. (C) Young mice showed that PAX8 staining (C³) was detected in PECs along Bowman’s capsule and co-localized with tdTomato reporter (C¹) creating a pink/purple color (C⁴) (marked with white arrows). PAX8 was not detected in podocytes (EGFP⁺ cells) (C²). (D) Aged mice showed that the majority of tdTomato⁺PECs (D¹) co-express PAX8 (D³) creating a magenta/white color (D⁴) (marked with solid arrow). However, newly generated podocytes from PEC origin (tdTomato⁺EGFP⁺) (D¹, D²) do not express PAX8 in the glomerular tuft of aged mice (marked with arrow heads). Scale bars represent 25μm or 5μm (insets).