Has the ability to tame harmful microorganisms in human mucus?

In the cold season, a runny nose comes out, but regardless of the season, many parts of the body such as the mouth or digestive tract are covered with sticky mucus. Researchers who were investigating mucus in the body found that mucus has a function to tame harmful microorganisms.

Catalina Ribbeck, a biophysicist at MIT’s College of Engineering, has been studying mucus secreted by humans for a long time. The mucus that covers the human body has a variety of functions, including softening the esophagus and stomach and helping sperm pass through the cervix in the vagina.

The mucin that the research team investigated is a viscous substance called mucin. Mucin is a protein mixture containing a large amount of sugar. It is responsible for cell protection and lubricants. According to the research team, mucins are substances that look like tiny brushes.

He points out that mucin research is not under way, saying that the material that occupies the most on the surface of our body is a substance that has been rarely studied. Another expert said that while mucus in the past thought was bad for public health and medicine, mucus and mucin research is complex and lags behind most other biomedical fields.

It can be explained that usually human mucus acts as a filter to catch external microbes. However, as a result of adding microorganisms to the mucus, the mucus does not completely resolve the microorganisms. Rather, microorganisms float freely in mucus, but in the immune system, it is explained that it is possible to solve the solution by floating mucus rather than agglomerated and difficult to penetrate lumps.

However, it is not necessary for the human body to die of all the microorganisms contained in the mucus. There are actually only a few microorganisms that adversely affect the human body, and a large number of microorganisms live inside and outside the human body. Among these are microorganisms that are beneficial to the human body. For example, microorganisms that live in mucus in the digestive tract help digest food.

The research team explains that the human body provides housing for the microbes, and in return, the microbes provide various services to the human body. Accordingly, the research team believes that the mucus is responsible for taming microorganisms into friendly residents.

The research team conducted an experiment to see how the O-linked sugar chains that make up mucin react to microorganisms. In the experiment, it was cultured with burned pig skin and human epithelial cells contained in Pseudomonas aeruginosa mucus, which does not cause disease even when infected with normal people, but causes disease in people with reduced immunity.

As a result of the experiment, it was found that the ability to infect Pseudomonas aeruginosa was lowered by the function of the O-linked sugar chain. In addition, the O-linked sugar chain blocked various genetic pathways including Pseudomonas aeruginosa attack on cells, secretion of toxins, communication between Pseudomonas aeruginosa, and formation of Pseudomonas aeruginosa masses. The research team expressed the function of the O-linked sugar chains that make up mucins as like fairy powder.

Although not published in this paper, this study also suggests that O-linked sugar chains can tame microorganisms such as Streptococcus mutans and yeast like Pseudomonas aeruginosa. In recent years, against antibiotics that kill microorganisms, the case that microorganisms evolve into superbugs that do not listen to antibiotics is considered dangerous. Therefore, it is explained that there is a possibility that an effective strategy against infection is to adopt a method of taming by weakening the infectivity rather than killing microorganisms. Related information can be found here .