Transcriptomic profiling of white blood cells reveals new insights into the molecular mechanisms of thalidomide in children with inflammatory bowel disease

Thalidomide has emerged as an effective immunomodulator in the treatment of pediatric patients with inflammatory bowel disease (IBD) refractory to standard therapies. Cereblon, a component of E3 protein ligase complex that mediates ubiquitination and proteasomal degradation of target proteins, has been identified as the primary target of thalidomide. Cereblon plays a crucial role in thalidomide teratogenicity, however it is unclear whether it is also involved in the therapeutic effects in IBD patients. This study aimed at identifying the mechanisms underpinning thalidomide action in pediatric IBD. Ten IBD pediatric patients clinically responsive to thalidomide were prospectively enrolled. RNA-sequencing and functional enrichment analysis was carried out on peripheral blood mononuclear cells obtained before and after treatment with thalidomide. RNA-sequencing analysis revealed 378 differentially expressed genes after treatment with thalidomide. The most deregulated pathways were cytosolic calcium ion concentration, cAMP-mediated signaling, eicosanoid signaling and inhibition of matrix metalloproteinases. Neuronal signaling mechanisms such as CREB signaling in neurons and axonal guidance signaling also emerged. Connectivity Map analysis revealed that thalidomide gene expression changes were similar to those induced by MLN4924, an inhibitor of NEDD8 activating enzyme, suggesting that thalidomide exerts its immunomodulatory effects by acting on the ubiquitin-proteasome pathway. In vitro experiments on cell lines confirmed the effect of thalidomide on altered candidate pathways observed in patients. These results represent a unique resource for enhanced understanding of thalidomide mechanism in patients with IBD, providing novel potential targets associated with drug response.Book of abstract: 4th Belgrade Bioinformatics Conference, June 19-23, 202