Figure 2.

Loss of stromal miRNAs resulted in renal hypodysplasia in FoxD1^GC;Dicer^fl/fl kidneys. (A, B) Histological analysis of E13.5 kidneys revealed no overt defects in FoxD1^GC;Dicer^fl/fl kidneys. (C, D) Similarly, no obvious defects were noted histologically in E15.5 control and FoxD1^GC;Dicer^fl/fl kidneys, with the appearance of developing nephrons. (E, F) At E18.5, a patent renal papilla was observed in both control and FoxD1^GC;Dicer^fl/fl kidneys. (G, H) In comparison to controls, FoxD1^GC;Dicer^fl/fl kidneys exhibited fewer developing glomeruli (yellow arrowheads) and a disorganized nephrogenic zone at E18.5. (I, J) A subset of juxtamedullary FoxD1^GC;Dicer^fl/fl glomeruli demonstrated an microaneurysmal phenotype at E18.5 (yellow arrowheads). a, artery. (K) At E18.5, FoxD1^GC;Dicer^fl/fl kidneys were smaller than control counterparts, as measured by renal length normalized to crown–rump length. ***P < 0.001 (Student’s t-test). (L) Since glomerular microaneurysms occur only within the juxtamedullary region, semiquantitative counting of 352 control and 406 FoxD1^GC;Dicer^fl/fl juxtaglomerular glomeruli (n = 3 kidneys for both controls and mutants) showed that approximately 28 ± 15% of FoxD1^GC;Dicer^fl/fl glomeruli had microaneurysms as denoted by atypical capillary ballooning with loss of patent capillary loops. ****P < 0.0001. Histological analysis was performed on at least three control and mutant embryos.