Figure 4.

Collagen IV staining increases along Bowman's capsule with accompanied migration of tdTomato⁺PECs in aged mice. (A–D) Representative confocal images of tdTomato⁺ (red), EGFP⁺ (green) and Collagen IV staining (blue) in young and aged mice. The inserts show separate channels of the outlined glomeruli, with superscripts: 1=tdTomato, 2=EGFP, 3=Collagen IV and 4=merged. (A) Young mice (OC) showed that tdTomato⁺PECs are limited to Bowman’s capsule (A¹) and EGFP⁺ podocytes to the glomerular tuft (A²). Collagen IV staining (blue) (A³) was used to delineate the kidney architecture. (B) Aged mice (OC) showed that differentiated yellow cells (tdTomato⁺PECs⁺ EGFP⁺) (marked with white arrows) were detected in the glomerular tuft (B¹, B²) which was accompanied by an increase in Collagen IV staining along BC (white arrow heads) (B³). (C) Young mice (JMC) showed that differentiated yellow cells (tdTomato⁺PECs⁺ EGFP⁺) were detected in some glomeruli along Bowman’s capsule (C¹, C²) which was accompanied by an increase in Collagen IV staining along BC (white arrow heads) (C³). (D) Aged mice (JMC) showed that differentiated yellow cells (tdTomato⁺PECs⁺ EGFP⁺) have migrated to the glomerular tuft (marked with white arrows) and co-express tdTomato (D¹), EGFP (D²), which was accompanied by an increase in Collagen IV staining along BC (white arrow heads) (D³). Scale bars represent 25μm or 5μm (insets).