Rapamycin and dexamethasone during pregnancy prevent tuberous sclerosis complex–associated cystic kidney disease
Morris Nechama, Yaniv Makayes, Elad Resnick, Karen Meir, Oded Volovelsky
Morris Nechama, Yaniv Makayes, Elad Resnick, Karen Meir, Oded Volovelsky
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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

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Figure 3

TSC1 deletion alters the expression of genes associated with inflammation in embryo renal PTCs and this is reversed by rapamycin treatment during pregnancy.

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TSC1 deletion alters the expression of genes associated with inflammati...
(A) Kidneys from E18.5 control and TSC1-null mice with and without rapamycin, given as in Figure 2A, were removed, cells dissociated, and proximal tubule cells stained with PE-conjugated prominin-1 antibody. Prominin-1–positive cells were monitored and sorted by FACS to isolate PTCs. Representative analyses of 3 samples for each group. (B) Heatmap visualization showing relative gene expression in sorted PTCs from control and Six2 Cretg/+ TSC1fl/fl embryos without (DMSO) and with rapamycin given during pregnancy. n = 3 in each group. (C) Validation by qPCR of changes in expression of genes associated with inflammatory response and macrophage polarization that were chosen based on B and C. n = 4 in each group. One-way ANOVA statistical analysis was used followed by Duncan’s post hoc test. *P < 0.05. (D) Heatmap of potential pathways affected by TSC1 deletion and the effect of rapamycin treatment on these pathways in PTCs. The changes in pathways were calculated according to the GSEA in B. The number 1 represents the ratio between Six2 Cre TSC1fl/fl PTCs treated with rapamycin vs. WT PTCs treated with DMSO; 2 represents the ratio between Six2 Cre TSC1fl/fl PTCs treated with DMSO vs. WT PTCs treated with DMSO; and 3 represents the ratio between Six2 Cre TSC1fl/fl PTCs treated with rapamycin vs. Six2 Cre TSC1fl/fl PTCs treated with DMSO. (E) GSEA analysis of the inflammatory response and complement pathways in Six2 Cre TSC1fl/fl PTCs compared with control WT PTCs. TSC, tuberous sclerosis complex; PTCs, proximal tubular cells; GSEA, gene set enrichment analysis; TSC, tuberous sclerosis complex.