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German researchers have discovered why sleep can sometimes be the best medicine. Sleep improves the potential ability of certain immune cells in the body to attach to their targets, according to a new study published Feb. 12 in the Journal of Experimental Medicine. The study, led by Stoyan Dimitrov and Luciana Besedovsky of the University of Tübingen, explains how sleep can fight an infection, while other conditions, such as chronic stress, can increase the vulnerability of the body. to the disease.
T cells are a type of white blood cell that plays a vital role in the body's immune response. When T cells recognize a specific target, such as a virus-infected cell, they activate sticky proteins, called integrins, that allow them to attach to their target and, in the case of one cell infected with a virus, kill it. Much is known about signals that activate integrins, but signals that may impair the ability of T cells to attach to their targets are less well understood.
Stoyan Dimitrov and colleagues at the University of Tübingen decided to study the effects of a diverse group of signaling molecules known as Gαs-coupled receptor agonists. Many of these molecules can suppress the immune system, but it is unclear whether they prevent T cells from activating their integrins and attaching to target cells.
Dimitrov et al. Found that certain Gα-coupled receptor agonists, including the adrenaline and norepinephrine hormones, the pro-inflammatory prostaglandin E2 and D2 molecules, and the neuromodulator adenosine, prevented T cells from activating their integrins after recognizing their target. "The levels of these molecules needed to inhibit the activation of integrins are observed in many pathological conditions, such as tumor growth, malaria infection, hypoxia and stress," Dimitrov explains. "This pathway could therefore contribute to the immune suppression badociated with these pathologies."
The adrenaline and prostaglandin levels drop as the body is asleep. Dimitrov and colleagues compared T-cells taken from healthy volunteers while they were sleeping or sleeping all night. T cells from dormant volunteers had significantly higher integrin activation levels than those from awake subjects. The researchers were able to confirm that the beneficial effect of sleep on the activation of T-cell integrin was due to decreased activation of Gαs-coupled receptors.
"Our results show that sleep can potentially improve the effectiveness of T-cell responses, which is particularly relevant given the high prevalence of sleep disorders and disorders characterized by sleep disorders, such as depression. , chronic stress, aging and shift work., "Luciana Besedovsky, author last author.
In addition to helping to explain the beneficial effects of sleep and the negative effects of conditions such as stress, the study of Dimitrov and colleagues could stimulate the development of new therapeutic strategies improving the ability of T cells to to stick to their targets. This could be useful, for example, for cancer immunotherapy, where T cells are urged to attack and kill tumor cells.
Reference: Dimitrov et al. 2019. J. Exp. Med. http://jem.rupress.org/cgi/doi/10.1084/jem.20181169?PR
Source: Rockefeller University Press
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