1. ¹Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
2. ²Division of Pediatric Nephrology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
3. ³Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Correspondence: Donald E. Kohan, Division of Nephrology, University of Utah Health Sciences Center, 30 North 1900 East, Salt Lake City, UT 84132, USA. E-mail: donald.kohan@hsc.utah.edu

Received 15 May 2008; Revised 30 October 2008; Accepted 4 November 2008; Published online 14 January 2009.

Abstract

Renal cysts in autosomal dominant polycystic kidney disease arise from cells throughout the nephron, but there is an uncertainty as to whether both the intercalated cells (ICs) and principal cells (PCs) within the collecting duct give rise to cysts. To determine this, we crossed mice containing loxP sites within introns 1 and 4 of the Pkd1 gene with transgenic mice expressing Cre recombinase under control of the aquaporin-2 promoter or the B1 subunit of the proton ATPase promoter, thereby generating PC- or IC-specific knockout of Pkd1, respectively. Mice, that had Pkd1 deleted in the PCs, developed progressive cystic kidney disease evident during the first postnatal week and had an average lifespan of 8.2 weeks. There was no change in the cellular cAMP content or membrane aquaporin-2 expression in their kidneys. Cysts were present in the cortex and outer medulla but were absent in the papilla. Mice in which PKd1 was knocked out in the ICs had a very mild cystic phenotype as late as 13 weeks of age, limited to 1–2 cysts and confined to the outer rim of the kidney cortex. These mice lived to at least 1.5 years of age without evidence of early mortality. Our findings suggest that PCs are more important than ICs for cyst formation in polycystic kidney disease.