NOD2- and disease-specific gene expression profiles of peripheral blood mononuclear cells from Crohn’s disease patients

Employing microarray assays, a total of 267 genes were identified that were significantly up- or downregulated in PBMCs of WT-NOD2 patients, compared to healthy donors after challenge with vitamin D (+/-D) and/or a combination (+/-LP) of LPS (lipopolysaccharide) and PGN (peptidoglycan) (p < 0.05; threshold: ≥ 2-fold change). For further analysis by real-time PCR, 12 genes with known impact on inflammation and immunity were selected that fulfilled predefined expression criteria. In a larger cohort of patients and controls, a disease-associated expression pattern, with higher transcript levels in vitamin D-treated PBMCs from 5 patients, was observed for three of these genes, CLEC5A (p < 0.030), lysozyme (LYZ; p < 0.047) and TREM1 (p < 0.023). Six genes were found to be expressed in a NOD2- dependent manner (CD101, p < 0.002; CLEC5A, p < 0.020; CXCL5, p < 0.009; IL-24, p < 0.044; ITGB2, p < 0.041; LYZ, p < 0.042). Interestingly, the highest transcript levels were observed in patients with heterozygous NOD2 mutations. PBMC`s of 3 patient and 3 controls were treated with vitamin D and/or a combination of LPS and PGN resulting in 8 triplicates (24 hybridization samples)