FIGURE 4:

Podocyte IRE1α deletion result in a reduction of WT1 and synaptopodin. (A–C) Kidney sections from 9-mo-old mice were stained with antibodies to WT1 (A), synaptopodin (B), and podocalyxin (C). Staining with nonimmune IgG is also presented (negative controls). Scale bars, 50 μm. (D, E) The number of WT1-positive nuclei per glomerulus (determined by colocalization with Hoechst nuclear stain; not shown) was assessed by visual counting. WT1 counts per glomerulus were comparable, but when expressed per 1000 µm² of glomerular area, WT1 counts were significantly lower in M Cre mice (*p = 4.6 × 10⁻⁵); 32 M + glomeruli from three mice and 48 M Cre glomeruli from three mice. (F) Synaptopodin-stained glomeruli were enlarged in M Cre mice (*p = 0.024). (G) Quantification of synaptopodin immunofluorescence per unit glomerular area showed that intensity was lower in M Cre mice (*p = 0.046). For F and G, 74 M + glomeruli from three mice and 69 M Cre glomeruli from three mice. (H) Podocalyxin-stained glomeruli were enlarged in M Cre mice (*p = 0.0013). (I) Podocalyxin fluorescence per glomerulus and fluorescence per unit glomerular area were comparable in both groups. For H and I, 58 M + glomeruli from three mice and 54 M Cre glomeruli from three mice.