An mTOR anti-sense oligonucleotide decreases polycystic kidney disease in mice with a targeted mutation in Pkd2.

Abstract

Autosomal dominant polycystic kidney disease (ADPKD) is the most common life-threatening hereditary disease in the USA. In human ADPKD studies, sirolimus, a mammalian target of rapamycin complex 1 (mTORC1) inhibitor, had little therapeutic effect. While sirolimus robustly inhibits mTORC1, it has a minimal effect on mTOR complex 2 (mTORC2). Polycystic kidneys of Pkd2WS25/- mice, an orthologous model of human ADPKD caused by a mutation in the Pkd2 gene, had an early increase in pS6 (marker of mTORC1) and pAktSer(473) (marker of mTORC2). To investigate the effect of combined mTORC1 and 2 inhibition, Pkd2WS25/- mice were treated with an mTOR anti-sense oligonucleotide (ASO) that blocks mTOR expression thus inhibiting both mTORC1 and 2. The mTOR ASO resulted in a significant decrease in mTOR protein, pS6 and pAktSer(473). Pkd2WS25/- mice treated with the ASO had a normalization of kidney weights and kidney function and a marked decrease in cyst volume. The mTOR ASO resulted in a significant decrease in proliferation and apoptosis of tubular epithelial cells. To demonstrate the role of mTORC2 on cyst growth, Rictor, the functional component of mTORC2, was silenced in Madin-Darby canine kidney cell cysts grown in 3D cultures. Silencing Rictor significantly decreased cyst volume and expression of pAktSer(473). The decreased cyst size in the Rictor silenced cells was reversed by introduction of a constitutively active Akt1. In vitro, combined mTORC1 and 2 inhibition reduced cyst growth more than inhibition of mTORC1 or 2 alone. In conclusion, combined mTORC1 and 2 inhibition has therapeutic potential in ADPKD.

• Authors: Kameswaran Ravichandran, Iram Zafar, Zhibin He, R Brian Doctor, Radu Moldovan, Adam E Mullick, Charles L Edelstein
• Journal: Human molecular genetics (Hum Mol Genet) Vol. 23 Issue 18 Pg. 4919-31 (Sep 15 2014) ISSN: 1460-2083 [Electronic] England
• PMID: 24847003 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected].

Chemical References

• Carrier Proteins
• Oligonucleotides, Antisense
• Rapamycin-Insensitive Companion of mTOR Protein
• TRPP Cation Channels
• polycystic kidney disease 2 protein
• rictor protein, mouse
• TOR Serine-Threonine Kinases
• Sirolimus

Topics

• Animals
• Carrier Proteins (genetics, metabolism)
• Cell Proliferation (drug effects)
• Disease Models, Animal
• Dogs
• Gene Expression Regulation (drug effects)
• Genetic Therapy (methods)
• Humans
• Kidney (drug effects, pathology)
• Madin Darby Canine Kidney Cells
• Mice
• Mice, Inbred C57BL
• Oligonucleotides, Antisense (administration & dosage)
• Polycystic Kidney Diseases (genetics, pathology)
• Rapamycin-Insensitive Companion of mTOR Protein
• Sirolimus (pharmacology)
• TOR Serine-Threonine Kinases (antagonists & inhibitors)
• TRPP Cation Channels (genetics, metabolism)