Rapamycin and dexamethasone during pregnancy prevent tuberous sclerosis complex–associated cystic kidney disease
Morris Nechama, … , Karen Meir, Oded Volovelsky
Morris Nechama, … , Karen Meir, Oded Volovelsky
Published June 2, 2020
Citation Information: JCI Insight. 2020;5(13):e136857. https://doi.org/10.1172/jci.insight.136857.
View: Text | PDF
Research Article Nephrology

Rapamycin and dexamethasone during pregnancy prevent tuberous sclerosis complex–associated cystic kidney disease

Abstract

Chronic kidney disease is the main cause of mortality in patients with tuberous sclerosis complex (TSC) disease. The mechanisms underlying TSC cystic kidney disease remain unclear, with no available interventions to prevent cyst formation. Using targeted deletion of TSC1 in nephron progenitor cells, we showed that cysts in TSC1-null embryonic kidneys originate from injured proximal tubular cells with high mTOR complex 1 activity. Injection of rapamycin to pregnant mice inhibited the mTOR pathway and tubular cell proliferation in kidneys of TSC1-null offspring. Rapamycin also prevented renal cystogenesis and prolonged the life span of TSC newborns. Gene expression analysis of proximal tubule cells identified sets of genes and pathways that were modified secondary to TSC1 deletion and rescued by rapamycin administration during nephrogenesis. Inflammation with mononuclear infiltration was observed in the cystic areas of TSC1-null kidneys. Dexamethasone administration during pregnancy decreased cyst formation by not only inhibiting the inflammatory response, but also interfering with the mTORC1 pathway. These results reveal mechanisms of cystogenesis in TSC disease and suggest interventions before birth to ameliorate cystic disease in offspring.

Authors

Morris Nechama, Yaniv Makayes, Elad Resnick, Karen Meir, Oded Volovelsky

×

Figure 4

Dexamethasone administered during pregnancy reduces cyst formation and mTORC1 activity in TSC mice.

Options: View larger image (or click on image) Download as PowerPoint
Dexamethasone administered during pregnancy reduces cyst formation and m...
(A) Renal sections of control and Six2 Cretg/+ TSC1fl/fl mice (P0) were stained with anti-F4/80 marker (macrophages) and anti–NF-κB P65. Scale bar: 50 μm. n = 3. (B) Western blot for P65 and control GAPDH in homogenized kidneys from control and TSC1 KO mice. (C) Quantification of the Western blot in B. *P < 0.05. n = 4. (D) Kidneys from mice as in A were removed. Cells were dissociated and stained with APC-conjugated F4/80. The percentage of F4/80+ cells was determined by FACS. WT (n = 6), Six2 Cre TSC1fl/fl (n = 4). *P < 0.05. (E) Representative H&E staining of kidney sections from Six2 Cretg/+ TSC1fl/fl mice treated with dexamethasone and control (PBS), showing reduced cyst formation after dexamethasone. Scale bar = 500 μm. (F) Quantification of the cyst area and number per section in the different groups as in F. Dexamethasone (n = 6) and control (n = 5). *P < 0.05. (G) Representative FACS analysis. Kidneys of WT, Six2 Cre TSC1fl/fl treated with either PBS or dexamethasone as indicated were dissociated and stained with APC-conjugated F4/80 and subjected to FACS analysis. (H) Quantification of the percentage of F4/80+ cells in each group as in G. WT (n = 5), Six2 Cre TSC1fl/fl treated with PBS (n = 4), and Six2 Cre TSC1fl/fl treated with dexamethasone (n = 4). *P < 0.05. (I) Sections as in E were stained for pS6 and P65. Scale bar: 50 μm. n = 3. (J) Kidneys were homogenized as in E and the expression of P65, pS6, and GAPDH were analyzed by Western blots (n = 4). (K) Quantification of the Western blots as shown in J. *P < 0.05. Unpaired t test was used for C, D, F, and K, and 1-way ANOVA statistical analysis was used followed by Duncan’s post hoc test for H. mTORC1, mTOR complex 1; TSC, tuberous sclerosis complex.