¹Institute for Inflammation Research IIR 7521, Rigshospitalet National University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark

Correspondence: Klaus Bendtzen, E-mail: kben@mail.dk

Received 11 November 2005; Accepted 20 January 2006; Published online 6 March 2006.

Abstract

1. Spironolactone (SPIR) binds to cytoplasmic mineralocorticoid receptors (MR) and functions as an aldosterone antagonist. Recently, the drug was shown to have an early suppressive effect on several immunoactive and proinflammatory cytokines.
2. To elucidate the mechanism behind this, the four MR-binding steroids SPIR, canrenone, 7-thiomethyl-spironolactone and aldosterone (ALDO) were investigated for effects on lipopolysaccharide- and phytohemagglutinin-A-activated human blood mononuclear cells. Gene expression was examined after 4 h using microarrays, and SPIR affected 1018 transcripts of the (=) 22,000 probed. In contrast, the SPIR-related steroids affected 17 or fewer transcripts. Combining SPIR and ALDO resulted in 940 affected transcripts, indicating that SPIR has an early gene-regulatory effect independent of MR.
3. The affected genes encode a large number of signalling proteins and receptors, including immunoinflammatory response genes and apoptosis and antiapoptosis genes. Apoptosis was evident in CD3-, CD14- and CD19-positive cells, but only after 18 h of exposure to SPIR.
4. The transcriptional network involving the differentially regulated genes was examined and the results indicate that SPIR affects genes controlled by the transcription factors NF-B, CEBP and MYC.
5. These observations provide new insight into the non-MR-mediated effects of SPIR.