Uncovering the Uncontrolled Chain Reaction
Professor Hegazy and his team spent five years investigating the intricate defense mechanisms of the immune system and how they go awry in the gut. Their research focused on a messenger molecule called oncostatin M (OSM). Produced by specific immune cells, OSM is an inflammation-promoting protein that had previously been noted for its presence in high concentrations within the inflamed tissue of IBD patients.
The Charité team sought to understand why OSM was so influential. Through the use of state-of-the-art single-cell sequencing, they were able to map the cellular landscape of the gut in unprecedented detail. They compared healthy tissue samples with those taken from patients at various stages of chronic intestinal disease. The results were striking: in inflamed tissue, an unexpected variety of cell types were found to have developed receptors, or binding sites, for oncostatin M. Simultaneously, an influx of immune cells began producing the protein in large quantities.
However, the most significant discovery involved the interaction between OSM and another protein, Interleukin-22 (IL-22). Under normal circumstances, IL-22 is a "guardian" of the gut. It supports the cells lining the intestine, helping to maintain the protective barrier that keeps bacteria and toxins from entering the bloodstream.
In the context of chronic inflammation, however, this protective mechanism is hijacked. The researchers found that IL-22 actually makes the gut lining more sensitive to the damaging effects of oncostatin M by increasing the number of OSM receptors.
"These two immune messengers work together and amplify the inflammation, drawing more immune cells into the intestine, like a fire that keeps getting more fuel and spreads," Professor Hegazy explains. This synergy creates a self-sustaining cycle of inflammation that the body cannot shut down on its own.
A Biomarker for Treatment Failure
The study’s findings also provide a potential explanation for why certain patients fail to respond to current standard-of-care treatments. The research team observed that patients with particularly high levels of oncostatin M were the most likely to experience treatment failure when using common biologics.
This suggests that OSM could serve as a vital biomarker. By measuring OSM levels in a patient’s tissue or blood, doctors might soon be able to predict whether a specific therapy will be effective before even starting it. This move toward personalized medicine would allow high-risk patients to bypass ineffective treatments and move directly to more aggressive or specialized interventions.
"It was especially interesting for us to see that patients with high levels of oncostatin M do not respond to several common therapies," says Hegazy. "This means that oncostatin M levels could help predict treatment failure and may serve as a biomarker for more severe disease. That’s exactly where we focused our efforts: we wanted to understand this signaling pathway better and find ways to block it with targeted treatments."
