The gut bacteria play an important role in order to keep us healthy. Research has indicated that these friendly little microorganisms present in your gut help you stay healthy, young, and lean.
But the question that arises here is how do they do this? One answer to this question is your immune system. Different studies have investigated the complex relationship between body immunity and gut bacteria.
These studies suggest that the interactions taking place between the bacteria and the gut of the host determine how your body responds to illness. The scientists have discovered it for some time how the microbiome of your gut can regulate the immune responses. However, a lot of details regarding the mechanisms by which these interactions occur remain unknown.
For example, how does your body’s immune system affect these bacteria so that they live “happily” inside the gut?
New research provides an answer to this question: vitamin A.
A team of scientists led by a professor of Brown University uncovered that vitamin A in moderate levels can prevent your immune system from becoming overactive and destroying the gut bacteria.
The findings of these studies are present in the journal Immunity and hold significant implications for several autoimmune diseases like Crohn’s disease.
Vitamin A and Immunity: The Relation
The gut microbiome comprises more than 100 trillion bacteria as per the researchers. These bacteria can be divided into Bacteroidetes and Firmicutes phyla.
By using a mouse model, the scientists found that the bacteria present in the human gut regulates the immune system of their host by adjustments in the levels of vitamin A. These adjustments are made by a protein responsible for the activation of this vitamin.
This protein is known as retinol dehydrogenase (Rdh7) because it can transform vitamin A into retinoic acid, the active form of vitamin A.
Moreover, scientists also found that Firmicutes bacteria- the bacteria that belong to the Clostridia family, can reduce the expression of Rdh7. Clostridia bacteria also cause the liver to store more quantities of vitamin A.
The scientists genetically designed mice lacking Rdh7 in the cells lining the intestines. These mice were found to have reduced levels of retinoic acid in their intestines. Moreover, they also had fewer amounts of immune cells that release the IL-22 molecule. IL-22 is a signaling molecule that regulates the antimicrobial response of your immune system.
The lead researcher of the study also pointed out certain other elements of the immune system. For example, immunoglobulin A cells along with other T cells the concentrations of which did not alter in the Rdh7 deficient mice model. This proved that Rdh7 is the only factor that controls how your immune system responds to the gut bacteria.
Novel Strategies for Autoimmune Diseases
The scientists explained the impact of this research. They said that by understanding the complex interactions between your gut bacteria and immunity, it is possible to pave way for newer therapies directed against autoimmune diseases.
Much of these diseases can be linked to an increased immune activation or response. However, in the present study, the scientists were able to unravel a completely new immune response.
This research can prove critical in the determination of therapies directed against autoimmune diseases like Crohn’s disease or IBD. It can prove to be equally efficient in vitamin A deficiency cases.