Today's Cell reveals another new feature of the nervous system: In the face of bacterial infections, I hit hard!

▎ academic longitude / report scientists from Harvard Medical School published a rather surprising study online in the journal Cell today.in the traditional impression, the nervous system is only the receiver and transmitter of information.but in this paper, scientists point out that it has changed the impression of "yes man" in the fight against bacterial infection and has chosen to fight hard.specifically, this study focused on a structure called Peyer's patches.this is a structure that only exists on the wall of the small intestine and is composed of lymphoid tissue and immune tissue.functionally, it can "scan" the intestinal environment and decide what to swallow into the intestine.it's thanks to their help that we can eat so much nutrition instead of waste.so, how does this structure know what to eat? It turns out that there are some special "M cells" on them.they are like gates that open when they encounter nutrients and close when they encounter harmful substances.this mechanism seems very delicate, but it can be used by harmful bacteria.for example, Salmonella can secrete transcription factors, promote the formation of more M cells and create more gates.then, they will forcibly open these openings, allowing more Salmonella to invade the intestine.according to the statistics of the Centers for Disease Control and Prevention (CDC), more than 1 million people are infected with Salmonella every year, and on average, people die of infection every day.} who would have thought that the nervous system would take the initiative to fight against bacterial infection? (photo source: pixabay) reading this, some friends may ask, what's the relationship between this and the nervous system? Don't worry. It's time for the nervous system.in order to study whether pain sensing gut neurons can protect against bacterial infection, the researchers conducted a comparative experiment: one group of mice had intact neurons, while the other two groups had no function (using genetic and chemical methods respectively).interestingly, mice with complete neuronal function had better resistance to Salmonella.and the reason behind this is quite unexpected - these neurons directly secrete a peptide called CGRP, which in the brain is associated with migraine attacks. in the gut, it can also make Salmonella feel "headache". it turns out that this peptide can inhibit the production of M cells, which virtually reduces the invasion point of Salmonella. In addition, CGRP could promote the growth of segmented filamentous bacteria. this kind of bacteria and Salmonella can be said to be antagonistic, will inhibit the latter's invasion of the intestinal tract. } the illustration of this study (photo source: reference [1]) "it is clear that the nervous system directly acts on infectious organisms and regulates immune capacity in a variety of ways. "said Professor Isaac M. Chiu, the corresponding author of the study. the researchers also pointed out that this could explain why some people who abuse painkillers are more likely to develop infections. in addition, we also hope to find ways to combat intestinal infection or inflammation by regulating neural signals. "our findings suggest that the nervous system is more than a simple 'perception and alarm' system. in the gut, nerve cells have more than these functions. they also regulate the immune capacity of the gut, maintain the homeostasis of the gut, and actively provide protection against infection. "Professor Chiu concluded. References: [1] Nicole y. Lai et al. (2019), gut innovating nociceptor neurons regulate Peyer's patch microfold cells and SFB levels to mediate Salmonella host defense, cell, DOI: more than a watchdog, retrieved December 5, 2019, from