Expression of inflammatory genes in the colon of ulcerative colitis patients varies with activity both at the mRNA and protein level.

BACKGROUND Ulcerative colitis (UC) is a chronic inflammatory disorder of the gastrointestinal tract involving aberrant activation of innate and adaptive immune responses. We aimed to study the expression profiles of the susceptibility gene Nod1 and selected pro- and anti- inflammatory cytokines during different stages of UC. METHODS 65 patients with mild, severe or remission stage of UC, and 22 normal colon mucosal biopsies from control individuals were included in the study for measuring the expression of nucleotide binding oligomerization 1(Nod1) and related pro- and anti-inflammatory cytokines using quantitative reverse transcription-PCR (qRT-PCR). mRNA expression levels were then correlated with severity of disease. In order to check their expression at the protein level, immunohistochemistry (IHC) was performed using Nod1, TNF-α, IFN-γ, IL-17, IL-23 and IL-13 antibodies. RESULTS Significant increases in Nod1 expression with simultaneous increases in pro-inflammatory cytokines TNF-α, INF-γ, IL-17 and IL-23 mRNA levels were observed in patients with mild and severe ulcerative colitis versus control individuals. The expression levels reverted back towards normal levels in patients during remission. However, mRNA expression of selected anti-inflammatory cytokines such as IL-11 and IL-13 were substantially lower in patients compared with control samples when measured using qRT PCR. Levels of IL-10 however, although exhibiting a decreasing trend, did not attain significance. CONCLUSIONS Our results show that with simultaneous increase in Nod1 expression, expression profiling of downstream inflammatory cytokines that are activated in UC patients, displayed different patterns according to the severity of the disease. These may be potential prognostic biomarkers for diagnosing UC patients.