Cell and surrounding vacuoles divide together, outnumbering lysosomes of immune cells
Self-produced protein SopB prevents immune cells from producing lysosomes
Anticipation of infection prevention using small molecule inhibitors or TFEB activators
Food poisoning, which always appears in summer when food is easily corrupted due to high temperatures, can be cured with conservative treatment to prevent dehydration, but if it is serious, it can lead to death, so prevention is important. Recently, a new study related to Salmonella, the causative agent of food poisoning, has appeared. The study, which revealed how Salmonella evades the body’s immunity, can help fight food poisoning infections in the future.
According to a paper published in Science Direct by researchers from the Department of Microbiology and Cell Biology (MCB) at the Indian Institute of Science (IISc) in April, Salmonella produces a protein called SopB that lowers the fusion and production of lysosomes in immune cells, thereby increasing the survival rate.
Salmonella, the causative agent of typhoid fever and food poisoning, is a type of proteobacteria belonging to the genus Salmonella of the family Enterobacteriaceae, and is divided into Salmonella enterica and Salmonella Bongori, and has more than 2600 serotypes (= antigen types). ) is further classified as
Salmonella mainly causes infection through consumption of undercooked or unclean poultry, meat, eggs, fruits and vegetables. Symptoms include fever, diarrhea, abdominal cramps and headaches. In Korea, there were cases of women in their 20s and men in their 60s who ate gimbap and naengmyeon two years ago and last year from food poisoning.
When Salmonella enters the human body, it exists in a bubble-like structure called a vacuole (SVC). The immune cells of our body detecting the bacteria produce reactive oxygen species (ROS) and reactive nitrogen species (RNS), and the vacuole and lysosome fuse with the decomposed vacuole to execute the manual to destroy the bacterial cell.
However, Salmonella escaped the attack of immune cells with a cunning strategy. When a bacterial cell divides, the vacuole also divides to place a new cell inside the vacuole. This strategy outnumbers the number of lysosomes that fuse with the vacuole, increasing the survival rate and leading to full-fledged proliferation.
The research team discovered that SopB, a protein produced by Salmonella bacteria, not only prevents the fusion of vacuoles and lysosomes, but also prevents the formation of lysosomes, and observed how SopB is involved.
As a result, they found that SopB prevents translocation of host cell transcription factor EB (TFEB) from the cytoplasm to the nucleus. Transcription factors are proteins that act as switches that bind to DNA and control the roles of target genes. The research team says this finding is very important because TFEB is responsible for the key regulation of lysosomal production.
“This study is novel in that it identifies a second mechanism by which SopB inhibits vacuole fusion with lysosomes and increases the ratio of vacuoles to lysosomes to survive,” said Deepsika Chakraborty, MCB professor and author of the study. For reference, a study that SopB mediates epithelial cell invasion was published in 2004 by a Canadian research team.
The research team suggested that using small molecule inhibitors of SopB or TFEB activators could help fight Salmonella infection.
Chemical News Reporter Park Chan-seo
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2023-06-01 23:45:06
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