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

Area of Science:

• Nephrology
• Developmental Biology
• Genetics

Background:

• Chronic kidney disease is a primary cause of mortality in tuberous sclerosis complex (TSC) patients.
• The mechanisms driving TSC-associated cystic kidney disease are not fully understood, and no preventative interventions exist.
• Targeted therapies are needed to address the significant morbidity and mortality associated with TSC kidney disease.

Purpose of the Study:

• To elucidate the mechanisms of cyst formation in TSC kidney disease.
• To investigate the efficacy of prenatal interventions targeting key molecular pathways.
• To identify potential therapeutic targets for preventing or treating TSC-related renal cysts.

Main Methods:

• Utilized targeted deletion of TSC1 in nephron progenitor cells in a mouse model.
• Administered rapamycin and dexamethasone to pregnant mice with TSC1-null offspring.
• Analyzed kidney development, cystogenesis, cell proliferation, gene expression, and inflammation in offspring.
• Assessed the impact of interventions on renal pathology and lifespan.

Main Results:

• TSC1 deletion in nephron progenitors led to cyst formation originating from injured proximal tubular cells with high mTOR complex 1 activity.
• Prenatal rapamycin treatment inhibited the mTOR pathway and tubular cell proliferation, preventing renal cystogenesis and extending the lifespan of TSC newborns.
• Dexamethasone administration reduced cyst formation by inhibiting inflammation and interfering with the mTORC1 pathway.
• Gene expression analysis revealed TSC1 deletion-induced modifications rescued by rapamycin during nephrogenesis.

Conclusions:

• Cystogenesis in TSC kidney disease is linked to injured proximal tubular cells and elevated mTORC1 activity.
• Prenatal administration of rapamycin or dexamethasone shows promise in preventing renal cystogenesis and improving outcomes in TSC.
• These findings reveal critical mechanisms and suggest potential prenatal therapeutic strategies for TSC-related cystic kidney disease.