When you eat, bile may "betray" you! The pathogenic mechanism of norovirus was found

In winter, apart from being easy to gain weight, what else is easy? It seems easy to be harassed by norovirus As a highly infectious disease, norovirus often "knocks down" a large number of people once it appears Since October 2019, norovirus has attacked many universities in China, such as Zhejiang University, Tianjin University of science and technology, Peking University and so on, resulting in vomiting and diarrhea of many students It has been half a century since the discovery of the virus, but no specific vaccine has been developed, and even the mechanism of disease caused by the virus is not clear A new study published in PNAS reveals the reason why norovirus successfully invades human cells: there are "traitors" in the human small intestine When the epithelial barrier is resistant to the virus, bile acids and ceramide in the bile help norovirus successfully cross the barrier and enter the small intestine cells for replication https://doi.org/10.1073/pnas.1910138117 The report comes from a team at Baylor College of medicine, one of the nation's most distinguished medical schools According to the report, the virus, which can cause foodborne diseases and acute diarrhea all over the world, infects small intestinal cells through a normal cellular process called endocytosis, by which cells take in nutrients from outside to maintain normal metabolic activity In experiments as early as 2016, the team found that some strains of norovirus need bile to replicate Therefore, in the recent study, researchers used human enteroids to investigate the bile components related to norovirus This is a kind of experimental model of human intestinal cells with the characteristics of small intestine and physiological activity, which is very close to the actual small intestine tissue During the experiment, the researchers found that bile acids and fatty ceramide in bile were necessary for the successful infection of human small intestine model Bile acid not only activated intestinal endocytosis, but also created an opportunity for norovirus to enter the cell Norovirus successfully infiltrated will replicate in the cell, resulting in human vomiting and diarrhea The researchers say that endocytosis is very effective for food borne viruses, because when people eat food, the normal response of the body is to secrete bile to the small intestine, while the virus infected with food, such as norovirus, is to rely on this natural body response to invade small intestinal cells, replicate and cause disease Of course, regulating the amount of bile acids and / or ceramide will help reduce norovirus infection In conclusion, this study not only introduced the mechanism of norovirus induced disease, but also proposed for the first time that bile acid can stimulate intestinal endocytosis This will support researchers to further explore the possibility of reducing norovirus infection by regulating bile acid and / or ceramide levels, so as to help people resist or get rid of norovirus infection.