Transcriptional Profiling of Native Inner Medullary Collecting Duct Cells from Rat Kidney

Abstract

Vasopressin acts on the renal inner medullary collecting duct (IMCD) to regulate water and urea transport. To obtain a ‘parts list’ of gene products expressed in the IMCD, we carried out mRNA profiling of freshly isolated rat IMCD cells using Affymetrix Rat 230 2.0 microarrays with approximately 31,000 features. 7913 annotated transcripts were found to be expressed above background in the IMCD cells. We have created a “IMCD Transcriptome Database” to make the results publicly accessible. Among the 30 transcripts with the greatest signals on the arrays were three water channels: aquaporin‐2, aquaporin‐3, and aquaporin‐4, all of which have been reported to be targets for regulation by vasopressin. In addition, the transcript with the greatest signal among members of the solute carrier (SLC) family of genes was the UT‐A urea transporter (Slc14a2), which is also regulated by vasopressin. The V2 vasopressin receptor was strongly expressed, but the V1a and V1b receptors did not produce signals above background. Among the 200 protein kinases expressed, the serum‐glucocorticoid regulated kinase (Sgk1) had the greatest signal intensity in the IMCD. Altogether, the results combine with proteomics studies of the IMCD to provide a framework for modeling complex interaction networks responsible for vasopressin action in collecting duct cells. Source of research support: Z01‐HL001285.