Nerve cells in the gut play a crucial role in the body’s ability to create an immune response to infection, according to new research.
According to scientists, the immune and nervous systems have co-evolved to respond to infectious threats. This means that scientists looking for ways to treat conditions such as inflammatory bowel disease or bronchial asthma associated with an overreaction of the immune system may also benefit from addressing the role of the nervous system.
The immune and neural systems do not act independently, but jointly, the authors say. The gut is home to many cells of the immune system that protect against parasites and other infections. It is also loaded with nerve cells. It has been found that cells of the immune system in the gut, called congenital group 2 lymphoid cells (ILC2s), are intertwined with nerve cells called cholinergic neurons.
The proximity of the cells made researchers wonder if they might be related. It was then that ILC2 cells were discovered to have a receptor for a protein called neuromedin U (NMU), which acts as a messenger for nerve cells. In laboratory experiments, researchers found that irradiating ILC2 cells with NMU causes ILC2 cells to proliferate and release chemicals called cytokines that can help trigger an immune response or inflammation.
The effect on NMU in mice infected with the intestinal parasite triggered inflammation and a potent immune response that helped the animals drive out the parasites faster. Conversely, mice genetically devoid of NMU receptors were more susceptible to parasites, allowing them to proliferate in rodent gut. Research shows that NMU-producing nerve cells help colonize ILC2 cells, allowing them to respond quickly and efficiently to infection.
This is true for multiple chronic inflammatory diseases that may be associated with this neural immune axis. The findings could have important implications for scientists studying inflammatory diseases, including asthma, food allergies, and inflammatory bowel disease. It is too early to say whether the NMU itself or its receptors could be targets for treatment, but the study of these pathways could lead to new therapies for such diseases.