Multi-omics empowered deep phenotyping of ulcerative colitis identifies biomarker signatures reporting functional remission states

Introduction Ulcerative colitis (UC) is a chronic disease with rising incidence and unclear etiology. Deep molecular phenotyping by multi omics analyses may provide novel insights into disease processes and characteristic features of remission states. Methods UC pathomechanisms were assessed by proteome profiling of human tissue specimen, obtained from five distinct colon locations for each of the 12 patients included in the study. Systemic disease-associated alterations were evaluated thanks to a cross-sectional setting of mass spectrometry-based multi-omics analyses comprising proteins, metabolites and eicosanoids of plasma obtained from UC patients during acute episodes and upon remission in comparison to healthy controls. Results Tissue proteome profiling indicated colitis-associated activation of neutrophils, macrophages, B- and T-cells, fibroblasts, endothelial cells and platelets, and hypoxic stress, and suggested a general down-regulation of mitochondrial proteins accompanying the establishment of apparent wound healing-promoting activities including scar formation. While pro-inflammatory proteins were apparently upregulated by immune cells, the colitis-associated epithelial cells, fibroblasts, endothelial cells and platelets seemed to predominantly contribute anti-inflammatory and wound healing-promoting proteins. Blood plasma proteomics indicated chronic inflammation and platelet activation, whereas plasma metabolomics identified disease-associated deregulations of gut and gut microbiome-derived metabolites. Upon remission, several, but not all, molecular candidate biomarker levels recovered back to normal. Conclusions The findings may indicate that microvascular damage and platelet deregulation hardly resolve upon remission but apparently persist as disease-associated molecular signature. This study presents local and systemic molecular alterations integrated in a model for UC pathomechanisms potentially supporting the assessment of disease and remission states in UC patients.