Analysis of Legionella pneumophila balance operation, our scientists find a new clue to conquer "air-conditioned lung"

Legionella pneumophila, a dangerous molecule hidden in the water supply pipes, reservoirs, cooling towers and air conditioning systems of cities, can cause severe pneumonia symptoms, commonly known as "air-conditioned lung" At present, how the "cunning" Legionella pneumophila "breaks through" the human immune system, resulting in "air-conditioned lung" and other diseases, has not been clearly recognized in the scientific community Recently, Professor Ouyang Songying's team from the school of life sciences of Fujian Normal University cooperated with Luo Zhaoqing's research group of Purdue University in the United States, which provided clues for further exploring the process of Legionella pneumophila infection The results were published in the Journal of the European Society of molecular biology "Legionella are not ordinary" bandits " They are not only good at using offensive weapons to" attack cities and pull out strongholds ", but also know how to effectively and reasonably recover and restore resources to ensure long-term sustainable development of Legionella Our research shows us how Legionella can pass the "mutual restriction weapons" of "MVCA mavc" In the process of infection, we can use its unique balance mechanism to prevent the immune system from hurting the bacteria themselves and the host cell from dying and affecting the reproduction of the bacteria because of the continuous suppression of the immune response " Ouyang song should say The "attack" of bacteria also needs to master a "degree" in daily life We have to face the threat of various pathogenic microorganisms, Legionella is one of them It is understood that at present, more than 30 Legionella species have been isolated, at least 19 of which are the pathogens of human pneumonia, the most common of which is Legionella pneumophila, accounting for 85% - 90% The pathogen was first found in Nanjing in 1982, and then in Beijing, Shanghai and other cities There is a long and complex struggle between pathogenic microorganisms and human beings They enhance their own virulence or pathogenicity through continuous reproduction, variation and evolution "Ubiquitination can regulate almost all processes in eukaryotic cells, especially plays an indispensable role in cell division and immune response." Ouyang song should introduce that many pathogens have evolved many ways to intervene the host ubiquitin modification system during the long-term game with the host cells, so as to enhance the infection efficiency and avoid the host immune "surveillance" "Legionella pneumophila mainly secretes about 330 effector proteins' weapons' into the host cells through a type IV secretion system called dot / ICM, and" hijacks "and" interferes "with the host's various signal pathways to inhibit the immune system of the body, so as to assist bacteria in the proliferation of the host cells." Ouyang song should say Ouyang song should point out that it should be noted that Legionella pneumophila can successfully infect the host and needs to master a "degree": these "weapons" need to be able to not only hijack and inhibit the host's immune system to complete the infection, but also can not cause excessive decline of the body's immunity due to over inhibition, resulting in cell death and loss of the "shelter" on which to live This is the secret to keep the balance of bacteria In the process of host immune response and cell survival, there is an important "role" - ube2n In previous studies, Luo Zhaoqing found that the effector protein mavc of Legionella pneumophila connected ubiquitin (UB) to une2n in a certain catalytic way to form ube2n UB, thus completing ubiquitination modification of ube2n and inhibiting its function Continuous inhibition of ube2n function will reduce the immunity of the body, lead to the death of infected cells, and is not conducive to the proliferation of Legionella in cells So what does Legionella pneumophila do to reverse this inhibition? The reporter of science and technology daily learned that in the latest research, scientists gave the answer "In our study, we found that the MvcA gene, located downstream of the effector protein MavC of Legionella pneumophila, encodes an enzyme, MvcA, which can specifically modify UBE2N-Ub Surprisingly, MVCA and mavc are highly similar in protein sequence and structure, and both have ubiquitin deamidase function " Ouyang song should say "If Legionella pneumophila is compared to the leader of" bandit ", the discovery is like the leader of" bandit "sent" two thieves "mavc and MVCA to cooperate with each other Before stealing, mavc is responsible for hoodwinking ube2n to make it easier to control the host After 5 hours, MVCA is responsible for releasing the host and then resuming the function of ube2n " Professor Ouyang song should use metaphor The results showed that Legionella pneumophila could control the expression of mavc and MVCA in the process of infection to meet the needs of balancing the ube2n function of infected cells in different time periods It is reported that another major study on Legionella pneumophila by ouyangsongying research group not only revealed the new function and catalytic mechanism of MVCA, but also provided clues to explore the reasons for the highly similar structure of two proteins but different biochemical functions, and also provided a new direction for the research and development of "air lung regulating" drugs