timing is everything. fight against infection T H 17 cells (green) in the cause of diseases of the small intestine when the body clock is disrupted.
generated image Xiaofei Yu, Shipra Vaishnava and Yuhao Wang
jet lag, shift work, and even evenings watching your tablet or smartphone can be taken from you 're sick. Indeed, the body's internal clock is set to two periods of light and darkness to 12 hours, and when this rate is broken, so that the immune system. One reason may be that the genes that define the body clock are intimately related to certain immune cells, according to a new study.
The discovery "was a happy accident," says Lora Hooper, an immunologist at the University of Texas Southwestern Medical Center in Dallas. She and her colleagues studied NFIL3, a protein that guides the development of certain system cells immune and turns on the activity of others. the gene encoding this protein is mutated in some human patients with inflammatory bowel disease, and mice lacking the gene NFIL3, the team found, had more so-called T H 17 cells in their intestines.
These cells are a type of immune cell known as a T cell. they derive their name a signal they produce, called interleukin 17, which points to other T cells to increase the immune response. in normal numbers, T H 17 cells, which live in the intestines, helping the body fight against bacterial and fungal infections. But when there are too many, the immune defense begins to cause the disease rather than prevent it. Stimulate NFIL3 levels in T cells growing in laboratory cultures resulted in fewer transform T H 17 cells, the researchers found, suggesting that the work of the protein is prevent T cells from entering this area of specialization. The absence of the protein, the team concluded, led to runaway T H 17 activity.
At this point, researchers had no reason to suspect a connection System- internal timing of our body also known as our circadian clock that responds to daily cycles of light and darkness . But as they continued to explore the link between NFIL3 and T H 17 cells, they found that some of the proteins produced by the "clock genes" of the body attach to genes NFIL3. In addition, cultured cells and mice whose clock genes have been experimentally produced tampered least T H 17 cells. researchers hypothesize that a key protein in the clock network binds to the gene NFIL3 to maintain the production of T H 17 cells synchronized with periods of light and darkness. and the team found that normal mice produce less NFIL3 and therefore more T H 17 cells during the day and night.
in a final experiment, the researchers gave the offset jet mouse. "We did not steal everywhere, "Hooper jokes. instead of this, the team shifted light / dark cycles of 6 hours rodents every 4 days. "It would be like stealing the United States to Europe, India and Japan and spent 4 days in each country," she explains. Mice with altered light cycles were almost twice as T H 17 cells in their spleens and intestines, compared with mice having a normal day, reports online today in Science of team. Mice schedule also mounted offset a stronger inflammatory response to irritation by chemical of an experimental test used to measure the sensitivity of the immune system which refers to animals may be more prone to inflammatory disease.
The finding adds to a body of research shows that a healthy pattern of light and darkness, sleep and waking, is essential for maintaining the immune system in balance more and more, says Hooper. It notes that inflammation is the basis of many chronic diseases, like heart disease, asthma, chronic pain, and many things ending in "-itis" as bursitis and dermatitis. Inflammatory conditions are more prevalent in developed countries, where circadian rhythms of people are chronically disturbed. Even people who do not work shifts or cross areas still wake schedules and sleep with shift light and darkness, Hooper said. "We all messed light cycles. We stay late, keep the lights on, look at our iPhones illuminated at 2 am"
Immunologist Dan Littman of New York University in New York found the results in cultured cells convincing. He cautions, however, that the carefully defined way of clock gene in T H 17 deletion may not be so tidy in a living animal. "Although NFIL3 is involved in how they show circadian disruption affects many other things." Stress hormones, bacteria of the intestine, and the actions of other types of T cells may also explain effects of experimental jet lag, he said.
Littman also notes that increased inflammation in animals jetlag was a response to an induced chemical irritation, and more research is needed to prove a link to an inflammatory disease or autoimmune disease.
Hooper agreed that this study is probably the tip of the iceberg, and more research will give deeper insight into the relationship between immune cells circadian rhythms. It hopes to collaborate with other researchers to determine whether T H 17 cells are increased in men with chronically altered light cycles. for now, she said, she tries to keep his own habits sleep longer aligned with nature, starting by limiting exposure to artificial light at night. "I turn off the lights, I draw the curtains, and I keep my iPhone off."
0 Komentar