miRNA Profiling in mucosal biopsies of Eosinophilic Esophagitis patients pre and post glucocorticoid steroid treatment

Eosinophlic esophagitis (EoE) is increasely recognized as an antigen-drived disorder. The goal of this study is to reveal the miRNA expression changes in EoE before and after a successful glucocorticoid steroid treatment. Total RNA was extracted from the esophageal epithelial layers of 5 paired paraffin-embedded biopsies before and after treatment with glucocorticosteroids using RecoverAll Total Nucleic Acid Extraction Kit for FFPE tissues (Ambion, Austin, TX). Five nanograms of total RNA was reverse-transcribed using the Taqman MicroRNA Reverse Transcription Kit and the Megaplex RT primer Human Pool A (Applied Biosystems). The reverse-transcribed cDNA was then pre-amplified in 12 cycles of PCR using Taqman PreAmp Master Mix and the Megaplex PreAmp primers, Human Pool A (Applied Biosystems). The cDNA’s were then diluted and loaded on to a Taqman Human miRNA Array card A (Platform GPL9731 ; Applied Biosystems), which contains probes for 377 distinct miRNAs. The Array cards were run on an ABI HT7900 qPCR instrument. Ct values were obtained for all miRNAs represented on the cards and fold changes in expression were calculated using the delta delta Ct (ddCt) method.