TFEB drives mTORC1 hyperactivation and kidney disease in Tuberous Sclerosis Complex.

Abstract

Tuberous Sclerosis Complex (TSC) is caused by TSC1 or TSC2 mutations, leading to hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and lesions  in multiple organs including lung (lymphangioleiomyomatosis) and kidney (angiomyolipoma and renal cell carcinoma). Previously, we found that TFEB is constitutively active in TSC. Here, we generated two mouse models of TSC in which kidney pathology is the primary phenotype. Knockout of TFEB rescues kidney pathology and overall survival, indicating that TFEB is the primary driver of renal disease in TSC. Importantly, increased mTORC1 activity in the TSC2 knockout kidneys is normalized by TFEB knockout. In TSC2-deficient cells, Rheb knockdown or Rapamycin treatment paradoxically increases TFEB phosphorylation at the mTORC1-sites and relocalizes TFEB from nucleus to cytoplasm. In mice, Rapamycin treatment normalizes lysosomal gene expression, similar to TFEB knockout, suggesting that Rapamycin's benefit in TSC is TFEB-dependent. These results change the view of the mechanisms of mTORC1 hyperactivation in TSC and may lead to therapeutic avenues.