Edinburgh Napier University

  Background Genetic studies have strongly linked autophagy to Crohn's disease (CD) and stimulating autophagy in CD patients may be therapeutically beneficial. The aim of this study was to evaluate the effect of current inflammatory bowel disease (IBD) drugs on autophagy and investigate molecular mechanisms of action and functional outcomes in relation to this cellular process. Methods Autophagy marker LC3 was evaluated by confocal fluorescence microscopy and flow cytometry. Drug mechanism of action was investigated by PCR Array with changes in signaling pathways examined by immunoblot and RT-qPCR. Clearance of adherent-invasive Escherichia coli (AIEC) and levels of pro-inflammatory cytokine tumour necrosis factor alpha (TNFα) were evaluated by gentamicin protection assays and RT-qPCR respectively. LC3 was analysed in peripheral blood mononuclear cells (PBMC) from paediatric patients by flow cytometry. Results Azathioprine induces autophagy via mechanisms involving modulation of mechanistic target of rapamycin (mTORC1) signaling and stimulation of the unfolded protein response (UPR) sensor PERK. Induction of autophagy with azathioprine correlated with the enhanced clearance of AIEC and dampened AIEC-induced increases in TNFα. Azathioprine induced significant increase in autophagosome bound LC3-II in PBMC populations ex vivo, supporting in vitro findings. In patients, the CD-associated ATG16L1 T300A single-nucleotide polymorphism did not attenuate azathioprine induction of autophagy. Conclusions Modulation of autophagy via mTORC1 and the UPR may contribute to the therapeutic Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation