胆固醇 z-bo 2020-10-30 342

　　A few days ago, in a research report published in the international journal Nature Microbiology, scientists at the University of Texas Southwestern Medical Center and other institutions found that when the immune system detects danger, certain bodies in the body Very sensitive to bacterial infections.

　　It can reorganize surface cholesterol to protect you from harm. It is expected that relevant research results will help develop new therapies that do not use antibiotics to fight infections. Scientists have long known that the mucous membranes of the intestines, lungs and other parts play an important role in protecting the body from systemic infections, but the body's immune system can control mucosal epithelial cells. I don't know how to enhance it. Prevents the defensive properties of bacteria and other infectious substances. Since immune cells such as macrophages are usually located near mucosal epithelial tissues, Alto researchers wanted to know whether these cells can secrete specialized molecules when the immune system detects a threat (such as an infectious agent).

　　I want to clarify through research. Helps epithelial cells improve their defense capabilities. To test this idea, the researchers cultured epithelial cells in a petri dish containing activated macrophages, and then added Listeria monocytogenes (which can cause listeriosis) and macrophages. As far as phage culture dishes are concerned, epithelial cells can show very obvious resistance to bacterial infections in culture dishes containing macrophages. Extensive studies of gene activity in macrophages have shown that infection with Listeria monocytogenes activates a special coding gene called cholesterol 25-hydroxylase (CH25H). Experimental results show that the small molecules produced by this gene can effectively inhibit epithelial cell infection.

　　As early as 25 years ago, researcher Rada Krishnan discovered the CH25H gene and devoted himself to cholesterol metabolism, studied how CH25H plays an important role, and then collaborated to study the gene. Begin to understand how to enhance the body's epithelial cell defense capabilities. competent. According to the researchers, CH25H can change cholesterol into a form called 25-hydroxycholesterol (25HC). Unlike cholesterol, which cannot be mixed with water, 25HC can be slightly mixed with water. Therefore, this characteristic of 25HC can be used to regulate the level of cholesterol in each cell of the human body. The function of 25HC is to turn off the activity of genes involved in cholesterol synthesis and at the same time activate the enzyme activity for cholesterol. Include conversion into a form that can be stored in a cell.

　　Researchers found that when 25HC was used to treat epithelial cells, the total cholesterol of epithelial cells did not change during the experiment. However, the researchers found 25HC using two different types of sensor molecules. It can remove the available cholesterol on the cell surface and suck it into the cell. One sensor molecule can absorb cholesterol that is easily available on the cell surface, while another sensor molecule can detect cholesterol molecules that are not easily available on the cell surface (because it binds to other lipid molecules).

　　Researchers said that within 1 hour of treatment, available cholesterol was severely removed from the cell surface and disappeared completely within 4 hours. Eliminate ready-made cholesterol or protect epithelial cells from Listeria infection, while enhancing their defense capabilities. When researchers take advantage of the ability to convert unavailable cholesterol into usable cholesterol, when the removed cells are treated with special enzymes, these cells become more susceptible to infection. This defense mechanism not only occurs when infected with Listeria monocytogenes, but also when infected with Shigella (the causative agent of bacterial diarrhea). This can explain the protective effect. Broad antibacterial properties. Next, the researchers plan to conduct in-depth studies to clarify the molecular mechanisms behind this phenomenon and determine which parts of the pathway are controlled or enhanced by drugs.

　　At the same time, the researchers plan to test whether this protection can be applied to viruses. infection. Finally, Dr. Aalto said that the detailed study of the above mechanism provides researchers with more clues to help potentially manipulate the cholesterol metabolism of human cells, thereby providing the human body with more clues to resist pathogens. He said that this might boost immunity.