A new study led by Marc Veldhoen, group leader at the Instituto de Medicina Molecular João Lobo Antunes (iMM; Portugal) and associate professor at the Faculdade de Medicina de Lisboa (FMUL) and published today in the scientific journal PNAS (Proceedings of the National Academy). of Sciences of the United States of America) discovered that the white blood cells that reside in the intestines, a specific group of immune cells called tissue-resident lymphocytes, use sugar as an energy source and have a faster metabolism than lymphocytes circulating in the blood. . These findings, supported by the “la Caixa” Foundation, show that, during infections, the local availability of sugar in the gut can be useful for the immune response and can have an impact on the faster resolution of an infection by the host, emphasizing the importance of a balanced diet for a healthy immune response.
Lymphocytes are known to circulate around the body in blood vessels, acting as a surveillance system, but there is a specialized group of lymphocytes that reside permanently in tissues. To function properly, it is important for cells to adapt to their environment. In this study, the researchers found that a specific group of lymphocytes that reside in the intestinal wall adapt their metabolism to this tissue.
Circulating lymphocytes spend most of their life in the lymph nodes, where there is a high availability of energy. It’s like the lymph nodes are full of lunch boxes. These cells can be permanently filled with energy, and even take a to-go box when they leave the lymph nodes to circulate around the body.”
Marc Veldhoen, study leader
However, tissue-resident lymphocytes do not have the same amount of energy available. “These cells are constantly in a state of semi-activation, ready to respond to challenges, such as infections. We found that these resident lymphocytes are able to adapt to their environment in the gut, and regulate their activity depending on the availability of glucose,” adds Marc Veldhoen.
“These cells quickly take up glucose to generate lactate or pyruvate, molecules that are used to produce energy,” says Vanessa Morais, also leader of the iMM group and collaborator of the study. In the gut, resident lymphocytes are able to produce energy faster than circulating lymphocytes.
To test whether glucose plays a role in the immune response to infection, the researchers used an intestinal infection model in mice. “We found that in mice infected with an intestinal pathogen, the local availability of glucose can determine the activation of resident lymphocytes and faster clearance of the infection,” explains Špela Konjar, first author of the study. These results show that resident lymphocytes are adapted to their environment, which in turn is used to regulate the response to infection. The effect of local glucose availability now discovered indicates that diet can affect intestinal immune cells, highlighting the importance of a balanced diet for the immune system.
Source:
Institute of Molecular Medicine
Journal reference:
Konjar, S., et al. (2022) Activation of resident T cells in intestinal tissue depends on metabolite availability. PNAS. doi.org/10.1073/pnas.2202144119.