This discovery could accelerate the body’s response to infection and autoimmune disorders. UT Southwestern Medical Center researchers report that disrupting the light-dark cycle of mice increased their susceptibility to inflammatory disease, indicating that the production of a key immune cell is controlled by the body’s circadian clock.
The study published in the Nov. 8 edition of Science identifies a previously hidden pathway by which the body’s circadian clock controls the numbers of key inflammatory cells called interleukin-17-producing CD4+ T helper cells (TH17). The work could lead to new ways to rev up the body’s immune response to infection or dampen that response in the case of autoimmune diseases in which the body attacks its own tissues, said senior author Dr. Lora Hooper, Professor of Immunology and Microbiology and a Howard Hughes Medical Institute (HHMI) Investigator.
Co-authors include Neuroscience Chair and HHMI Investigator Dr. Joseph Takahashi, whose discovery of the mouse and human clock genes led to a description of a conserved circadian clock mechanism in animals. The lead author is Xiaofei Yu, an Immunology student in the UT Southwestern Graduate School of Biomedical Sciences.
“Virtually all life forms on Earth undergo physiological and behavioral changes on a 24-hour daily, or circadian, cycle in accordance with the changes in natural light. Human beings are no exception. Many of our physiological processes, such as eating and sleeping, vary dramatically between day and night. Such processes are controlled by a group of proteins, collectively termed the ‘circadian clock,’ which function together in individual cells, capturing light cues from the visual and nervous systems and using these cues to regulate gene expression,” explained Dr. Hooper, who holds appointments in the Center for the Genetics of Host Defense and the Cancer Immunobiology Center.