Research - Activity Tests

Inflammatory bowel disease (IBD)

When inflammations are caused by the mailfunction of the immune system without dangerous invaders or necrotic conditions being present pathological inflammations are developed.

One example are inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, whose pathogenesis is widely unknown. A disorder in the regulation/communication of intestinal epithelial cells, immune cells and germs is suspected causing an exaggerated reaction of the immune system (inflammation).

Heme oxygenase-1 enzyme activity

The anti-inflammatory effect of HO-1 is based on the enzyme activity which induces multiple actions that lead overall to a reduction of the inflammation:

Transformation of heme into biliverdin via heme oxygenase-1 (HO-1) and further reaction to bilirubin

In order to search for compounds which act on IBD via HO-1 stimulation different intestinal epithelial cell lines are used as in vitro model systems.

Identification of heme oxygenase-1 stimulators

The gene expression of HO-1 is regulated by the transcription factor Nrf2. In the cell Nrf2 exists as a complex with the chaperon Keap1. The sequential disrupture of the Keap1-Nrf2-complex leads to gene expression of HO-1:

In order to identify unknown HO-1 stimulators the activity of many different compounds, which contain α,β-unsaturated carbonylsubstructures, are tested concerning their ability to activate heme oxygenase-1 stimulation.

To characterize HO-1 stimulation the following methods are used:

• Stimulation of intestinal epithelial cells and quantification of enzyme activity
• Examination of gene expression through mRNA quantification
• Quantification of protein expression with Western blotting and ELISA
• Reaction kinetics with NMR spectroscopy and UV/VIS spectroscopy
• Cytotoxicity tests