2021-10-25

Rewriting textbooks, red blood cells have new functions

By yqqlm yqqlm

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a new study published in Science Translational Medicine shows that red blood cells not only carry oxygen, but also carry DNA fragments of other cells, such as DNA from bacteria or parasites, and report directly to the immune system, There may be serious diseases in the body

Rewriting textbooks, red blood cells have new functions

after discovering this new function of red blood cells, researchers at the Perelman School of medicine at the University of Pennsylvania finally solved a puzzle encountered in clinical treatment: why do many patients have anemia in the intensive care unit</ Novel coronavirus pneumonia: “p>

has been developing for a long time what causes acute anemia due to sepsis, trauma, new crown pneumonia, bacterial infection or parasitic infection. This discovery first explains a mechanism of acute inflammatory anemia,” said Professor Nilam Mangalmurti, a research professor. In this study, novel coronavirus pneumonia was examined by p>

in 50 patients with sepsis and 100 new crown pneumonia patients. The red blood cells of these patients were found to be more than 40% of the blood cells, and a protein called TLR9 was detected on the surface. This receptor protein is often associated with inflammation and can activate the immune response

researchers observed through a series of in vitro experiments that through TLR9 on the surface, red blood cells can bind CpG rich DNA molecules, including those from bacteria and Plasmodium, as well as mitochondrial DNA released after cell damage. With the increase of bound DNA, the structure and morphology of erythrocytes changed significantly. The structural changes of cell membrane lead to more exposure of the binding region between TLR9 and nucleic acid, which can bind more DNA molecules

Rewriting textbooks, red blood cells have new functions(1)

these unrecognized red blood cells, like sentinels, quickly alerted the immune system, leading to the rapid arrival of immune cells called macrophages. The researchers injected some red blood cells combined with CpG DNA into mice. After a few hours, these red blood cells were swallowed by immune cells in passive objects. At the same time, the interferon signal pathway in animals is enhanced, indicating that innate immunity has been triggered

Rewriting textbooks, red blood cells have new functions(2)

in this case of inflammation, as these red blood cells carrying DNA are cleared one after another, it is not difficult to understand why patients have related anemia problems. The researchers examined some patients with viral pneumonia and sepsis secondary to new crown infection and found that the more mitochondrial DNA bound to erythrocytes, the higher the severity of anemia and disease

“in our intensive care unit, almost all critically ill patients will have anemia. Usually, when this happens, the standard practice is to give them blood transfusion, but blood transfusion will be accompanied by a series of problems, including acute lung injury and increase the risk of death.” Professor mangalmurti said, “Now that we have a deeper understanding of the mechanism of anemia, we can find new treatments for acute inflammatory anemia without blood transfusion. For example, targeted blocking of TLR9 on red blood cells.”

in addition to developing new therapies for patients with acute inflammatory anemia, this new discovery of red blood cells may also provide new ideas for diagnosis, the researchers pointed out. For example, doctors may be able to test red blood cells in patients with pneumonia and determine the type of pathogen according to the surface bound DNA, so as to use antibiotics more accurately