High-Dose Everolimus May Induce Pro-Inflammatory/Fibrotic Transcriptomic Changes in Bronchial Epithelial Cells from Cystic Fibrosis Patients

BACKGROUND: Solid-organ transplantation is an available therapeutic option for cystic fibrosis (CF) patients without lung transplantation. However, the use of immunosuppressive agents may cause severe adverse events. In particular, patients treated with mTOR-inhibitors (mTOR-I) may aggravate pulmonary complications. It has been recently described that these drugs may induce ep-ithelial to mesenchymal transition (EMT) of the airway cells. OBJECTIVE: The purpose of this study was to evaluate the effects of mTOR-I on primary bron-chial epithelial cells carrying F508del. Materials and Methods: Human bronchial epithelial cells homozygous for F508del were treated with 5 and 100 nM EVE for 24 hours, and their RNA was extracted and hybridized to the Human HT-12 v3 Expression BeadChip (Illumina). The microarray results were validated by Real-Time PCR. The transepithelial resistance was measured by a Millicell-ERS ohmmeter. RESULTS: High dosage EVE induced a significant up-regulation of 48 genes and a down-regulation of 14 genes. After pathway analysis by GSEA, we found that most of them were impli-cated in the inflammatory and pro-fibrotic pathways. Real-time PCR confirmed that 100 nM EVE was able to up-regulate some identified genes (IL-1alpha, IL-8, Pim-1) as well as pro-fibrotic ele-ments (alpha-SMA, connective tissue growth factor, and metalloproteinase-12). In addition, a high dosage of EVE was also able to reduce transepithelial resistance. In contrast, a lower level of EVE did not produce similar effects. CONCLUSIONS: Although performed in vitro, our study suggested that, in solid organ transplant recipients with CF without a lung transplant, mTOR-I should be used at a low dosage to reduce its contribution to pulmonary inflammation and fibrosis.