Kidney-specific inactivation of Ofd1 leads to renal cystic disease associated with upregulation of the mTOR pathway

Hum Mol Genet. 2010 Jul 15;19(14):2792-803. doi: 10.1093/hmg/ddq180. Epub 2010 May 5.

Abstract

The oral-facial-digital type I syndrome (OFDI; MIM 311200) is a rare syndromic form of inherited renal cystic disease. It is transmitted as an X-linked dominant, male lethal disorder and is caused by mutations in the OFD1 gene. Previous studies demonstrated that OFDI belongs to the growing number of disorders ascribed to dysfunction of primary cilia. We generated a conditional inactivation of the mouse Ofd1 gene using the Ksp-Cre transgenic line, which resulted in a viable model characterized by renal cystic disease and progressive impairment of renal function. The study of this model allowed us to demonstrate that primary cilia initially form and then disappear after the development of cysts, suggesting that the absence of primary cilia is a consequence rather than the primary cause of renal cystic disease. Immunofluorescence and western blotting analysis revealed upregulation of the mTOR pathway in both dilated and non-dilated renal structures. Treatment with rapamycin, a specific inhibitor of the mTOR pathway, resulted in a significant reduction in the number and size of renal cysts and a decrease in the cystic index compared with untreated mutant animals, suggesting that dysregulation of this pathway in our model is mTOR-dependent. The animal model we have generated could thus represent a valuable tool to understand the molecular link between mTOR and cyst development, and eventually to the identification of novel drug targets for renal cystic disease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Cilia / genetics
  • Cilia / metabolism
  • Disease Progression
  • Dogs
  • Epithelial Cells / metabolism
  • Epithelial Cells / pathology
  • Female
  • Gene Silencing / physiology*
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Intracellular Signaling Peptides and Proteins / physiology
  • Kidney / metabolism*
  • Kidney / pathology
  • Kidney Diseases, Cystic / genetics*
  • Kidney Diseases, Cystic / metabolism
  • Kidney Diseases, Cystic / pathology
  • Male
  • Mice
  • Mice, Transgenic
  • Organ Specificity / genetics
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Protein Serine-Threonine Kinases / physiology
  • Proteins / antagonists & inhibitors
  • Proteins / genetics*
  • Proteins / metabolism
  • Signal Transduction / physiology
  • TOR Serine-Threonine Kinases
  • Up-Regulation

Substances

  • Intracellular Signaling Peptides and Proteins
  • OFD1 protein, mouse
  • Proteins
  • mTOR protein, mouse
  • Protein Serine-Threonine Kinases
  • TOR Serine-Threonine Kinases