Ex Vivo Modeling of Chemical Synergy in Prenatal Kidney Cystogenesis

Abstract

Cyclic adenosine monophosphate (cAMP) drives genetic polycystic kidney disease (PKD) cystogenesis. Yet within certain PKD families, striking differences in disease severity exist between affected individuals, and genomic and/or environmental modifying factors have been evoked to explain these observations. We hypothesized that PKD cystogenesis is accentuated by an aberrant fetal milieu, specifically by glucocorticoids. The extent and nature of cystogenesis was assessed in explanted wild-type mouse embryonic metanephroi, using 8-Br-cAMP as a chemical to mimic genetic PKD and the glucocorticoid dexamethasone as the environmental modulator. Cysts and glomeruli were quantified by an observer blinded to culture conditions, and tubules were phenotyped using specific markers. Dexamethasone or 8-Br-cAMP applied on their own produced cysts predominantly arising in proximal tubules and descending limbs of loops of Henle. When applied together, however, dexamethasone over a wide concentration range synergized with 8-Br-cAMP to generate a more severe, glomerulocystic, phenotype; we note that prominent glomerular cysts have been reported in autosomal dominant PKD fetal kidneys. Our data support the idea that an adverse antenatal environment exacerbates renal cystogenesis.

Aquaporin‐1 retards renal cyst development in polycystic kidney disease by inhibition of Wnt signaling

“…Our work confirmed that there were cysts derived from proximal tubule in Pkd1 flox/flox ; Ksp‐Cre mice and that AQP1 deletion promoted proximal tubule cysts but not collecting duct cysts. In embryonic kidney model, immunofluorescence revealed that the cysts were mainly derived from proximal tubule and AQP1 located in the cells lining the cysts, which is consistent with previous data (74). These data suggest that AQP1 promoted cyst development in proximal tubule.…”

Planar cell polarity genes Celsr1 and Vangl2 are necessary for kidney growth, differentiation, and rostrocaudal patterning

“…Metanephric kidneys were harvested from wild-type mice at embryonic day (E)13.5 and whole-mount immunostaining for calbindin-D28K was undertaken18, 19 to visualize the ureteric tree using optical projection tomography (OPT) 20 . Inspection of images of wild-type metanephroi (Figure 1a) revealed a complex ureteric tree.…”

“…In contrast with heterozygotes, Celsr1 Crsh/Crsh kidneys had abnormal histology, with apparently dilated cortical tubules (Figure 3a and f). Despite this aberration, normal-appearing uromodulin-positive loops of Henle 19 were found in the medulla of Celsr1 Crsh/Crsh kidneys, and the mutant organ contained a renal pelvis (Supplementary Figure S2). Immunohistochemistry for the apical membrane marker atypical protein kinase C 23 showed no aberration in polarity in Celsr1 Crsh/Crsh kidneys (Supplementary Figure S3).…”

Anticystogenic activity of a small molecule PAK4 inhibitor may be a novel treatment for autosomal dominant polycystic kidney disease

“…Metanephric organ cultures have been used to determine whether embryonic kidney tubules can be stimulated to form cysts and as a way to rapidly assess whether various drugs can inhibit or slow cystic progression 29–31 . Under basal culture conditions, Pkd -1 wild-type kidneys from embryonic day 13.5 mice grow in size and continue ureteric bud branching and tubule formation over a 4- to 5-day period.…”

“…Ex vivo cystogenesis assay was performed as previously described 30,31 . Briefly, metanephroi were dissected from embryonic mice at E13.5 and placed on transparent Transwell cell culture inserts (Corning).…”