TiO2 nanoparticles abrogate the protective effect of the Crohn disease-associated variation within the PTPN22 gene locus

TiO2 levels in intestinal biopsies from IBD patients with or without the autoimmunity- associated PTPN22 variant were measured and correlated to gene expression of immune modulatory molecules. Wild-type and PTPN22 variant mice (PTPN22-R619W) were treated with dextran sodium sulfate (DSS) and TiO2. Changes on the cellular and molecular level were investigated using bulk and single cell RNA sequencing.