cDNA microarray analysis reveals new candidate genes possibly linked to side effects under mycophenolate mofetil therapy

Abstract

Background: Mycophenolate mofetil (MMF) the prodrug of mycophenolic acid is usually well tolerated. Side effects such as anemia and diarrhea occur in approximately 10%-15% of patients. The aim of this study was to examine in a rat model the effect of MMF on gene expression in liver and gut to identify target genes with possible relevance to MMF side effects.

Methods: Twelve Wistar rats were treated with 40 mg/kg body weight MMF orally for 21 days. Controls (n=9) received vehicle only. RNA was extracted from liver, jejunum, ileum, and colon and transcribed into cDNA. Regulated genes were identified in liver by DNA microarray experiments. Gene regulation was verified in liver and gut using quantitative real-time PCR on the LightCycler instrument. Transcription elongation factor 2 served as reference gene.

Results: Microarray analysis revealed that major alpha-hemoglobin, polymeric immunoglobulin receptor, catalase, and CCAAT/enhancer protein alpha gene expression were down-regulated in livers of MMF-treated rats 10-, 5.5-, 4-, and 5-fold, respectively. These findings could be confirmed through quantitative real-time PCR analysis of gene expression in liver, ileum, jejunum, and colon.

Conclusion: Using microarray analysis and a rat model four candidate genes which may be functionally linked to side effects (major alpha-hemoglobin-->anaemia; polymeric immunoglobulin receptor-->protection of mucosa; catalase and CCAAT/enhancer protein alpha-->oxidative stress) of MMF therapy were identified.