The immune system exercises constant vigilance to protect the body from external threats, including what the person eats and drinks. A careful balancing act plays out as digested food travels through the intestine. Immune cells must remain alert to protect against harmful pathogens such as Salmonella, however, their activity also needs to be tempered since an overreaction can lead to too much inflammation and permanent tissue damage. Now, a study from researchers at Rockefeller University shows that neurons play a role in protecting intestinal tissue from over-inflammation. The team state that their findings could have treatment implications for gastrointestinal diseases such as irritable bowel syndrome. The study is published in the journal Cell.
Previous studies show that intestinal tissue is continuously exposed to numerous microbe-and food-derived antigens. In order to deal with pathogens, resistance to infections needs to be coupled with tolerance to the delicacy of the system. It is known that different populations of macrophages are among the many types of immune cells present in intestinal tissue. Lamina propria macrophages are found very close to the lining of the intestinal tube, while muscularis macrophages are in the deeper tissue layer, distant from what passes through the intestine. Although the role of environmental cues in the adaptation of immune cells to these conditions has been increasingly investigated, the nature of these signals and the mechanisms by which they influence immune cells are still unclear. The current study identifies a mechanism by which neurons work with immune cells to help intestinal tissue respond to perturbations without going too far.
The current study uses an imaging technique which allows the lab to view cellular structures three-dimensionally, as well as the differences between the two populations. In addition to variations in how the cells look and move, the group also observed that intestinal neurons are surrounded by macrophages. Results show that lamina propria macrophages preferentially express pro-inflammatory genes. Data findings show, in contrast, that the muscularis macrophages preferentially express anti-inflammatory genes, and these are boosted when intestinal infections occur.
Results show that muscularis macrophages carry receptors on their surface that allow them to respond to norepinephrine, a signaling substance produced by neurons. The team state that the presence of this receptor might indicate a mechanism by which neurons signal to the immune cells to put a stop to inflammation. They go on to add this suggests that one of the main signals which induces a different response to infection appears to come from neurons, which are encircled by the muscularis macrophages.
The group also observed that the muscularis macrophages are activated within one to two hours following an infection, significantly faster than a response would take if it were completely immunological, and not mediated by neurons. The lab state that because these deeply embedded macrophages receive signals from neurons, they are able to respond rapidly to an infection, even though they are not in direct contact with the pathogen.
The team surmise that the global medical community now have a much better picture of how the communication between neurons and macrophages in the intestine helps to prevent potential damage from inflammation. They go on to add it’s plausible that a severe infection could disrupt this pathway, leading to the tissue damage and permanent gastrointestinal changes seen in diseases such as irritable bowel syndrome. For the future, the researchers state that these findings could be harnessed to develop treatments for such diseases.
Source: The Rockefeller University
brain circuitry, healthinnovations, immune cell, immune system, immunology, inflammation, intestinal neuron, irritable bowel syndrome, manual body regulation, neuroinnovations, second brain, whole-body manual regulation
Michelle Petersen is the founder of Healthinnovations, having worked in the health and science industry for over 21 years, which includes tenure within the NHS and Oxford University. Healthinnovations is a publication that has reported on, influenced, and researched current and future innovations in health for the past decade.
Michelle has been picked up as an expert writer for Informa publisher’s Clinical Trials community, as well as being listed as a blog source by the world’s leading medical journals, including the acclaimed Nature-Springer journal series.
Healthinnovations is currently indexed by the trusted Altmetric and PlumX metrics systems, respectively, as a blog source for published research globally. Healthinnovations is also featured in the world-renowned BioPortfolio, BioPortfolio.com, the life science, pharmaceutical and healthcare portal.
Most recently the Texas A&M University covered The Top 10 Healthinnovations series on their site with distinguished Professor Stephen Maren calling the inclusion of himself and his team on the list a reflection of “the hard work and dedication of my students and trainees”.
Michelle Petersen’s copy was used in the highly successful marketing campaign for the mega-hit film ‘Jumanji: The Next Level, starring Jack Black, Karen Gilian, Kevin Hart and Dwayne ‘The Rock’ Johnson. Michelle Petersen’s copywriting was part of the film’s coverage by the Republic TV network. Republic TV is the most-watched English language TV channel in India since its inception in 2017.
An avid campaigner in the fight against child sex abuse and trafficking, Michelle is a passionate humanist striving for a better quality of life for all humans by helping to provide traction for new technologies and techniques within healthcare.