Epithelial stem cell DNA damage can accumulate and turn into bowel cancer if it is not eradicated. Damaged cells can either be repaired, or, if the damage is too excessive, the cells can program their own death. Researchers have discovered that this repair mechanism is not only triggered by stem cells but also by the body's own immune system, thereby preventing colon cancer.
In the study, published in Nature, the investigators discovered that the immune system is able to recognize glucosinolates, naturally occurring plant components that are genotoxic when consumed. Once recognition occurs, the immune system releases interleukin-22 (IL-22), a cytokine that regulates DNA damage repair. Interleukin-22 then alerts epithelial stem cells to the DNA damage so that they can begin repairing the damage.
"The immune system acts like a sensor that detects genotoxic food components," explained one of the study's authors, Andreas Diefenbach, PhD, Director of Charité's Institute of Microbiology, Infectious Diseases and Immunology and Professor in Precision Medicine at the Berlin Institute of Health. "Switching off this sensor results in a significant increase in cases of bowel cancer."
These findings led the scientists to conclude that the immune system is more complex than previously believed. "The immune system monitors both the healthy growth and function of different organs in the body," remarked Dr. Diefenbach.
Further research needs to be conducted concerning the relationship between food components, intestinal flora, the intestinal wall, and the immune system. "It is here that we may find the key to why there are so many inflammatory disorders," commented Dr. Diefenbach.
For More Information
Gronke K, Hernandez PP, Zimmermann J, et al (2019). Interleukin-22 protects intestinal stem cells against genotoxic stress. Nature. [Epub ahead of print] DOI:10.1038/s41586-019-0899-7
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