PNAS: Host cell fusion alerts the immune system when a bacterial infection occurs, causing damage to the host cell.

26, 2020 /PRNewswire/ -- False nasal anthrax (Burkholderia pseudomallei) is a bacteria in the soil that can cause mold disease, a tropical disease with high morbidity and mortality.
recently, researchers at the Yong Loo Lin School of Medicine (NUSMed) at the National University of Singapore found that a false nasal anthrax Bockhold infection triggers a series of events that stimulate the host's immune system and cause infected cells to self-destruct.
the study was published in the prestigious Proceedings of the National Academy of Sciences.
when the false nasal anthrax Burkhold infects cells, it causes the infected cells to fuse with other cells around them, forming polynuclear cyanosis. Dr. Joanne Wei-Kay Ku and Associate Professor Gan Yunn Hwen of the Department of Biochemistry and Infectious Diseases at the
NUSMed And the Infectious Diseases Project found that this cell fusion event stimulates the type 1 interferon (IFN) signaling pathway, which regulates the immune system against invading pathogens such as bacteria and viruses.
picture source: Tom Misteli, Ph.D., and Karen Meaburn, Ph.D. at THE NIH IRP, it is interesting to note that it is the behavior of cell fusion, not bacterial infection, that triggers the immune system, because when chemicals are added to induce cell fusion, it also stimulates the type 1 IFN signaling pathway.
researchers found that the cytocells behave differently from normal cells.
first, they start to split, but they can't complete the process.
second, DNA in the giant cells is damaged, making it more unstable (prone to mutations, etc.).
these are the mature conditions for cells to convert into cancer cells. One of the characteristics of
damaged, unstable DNA is the presence of micronucleonuclears, which are structures formed when DNA fragments are not properly separated during cell division.
when these microcores break, which break easily, DNA can get close to the factors in the cytoplasm. Professor
Gan and his team observed the corresponding activation of the micronucleus in the giant cells and the immune system cGAS-STING pathway, which senses misplaced DNA and causes type 1 IFN signals.
however, under the impact of wide-ranging cell fusion, the activated cGAS-STING pathway initiates an unusual death procedure called autophagy, rather than producing type 1 IFN.
this causes these abnormal macrocells to self-destruct.
Because unnatural cell fusion is often accompanied by DNA damage and instability, this killing mechanism can be a powerful way to destroy them before cell carcinoma.
our immune system's ability to "perceive" different forms of danger, such as viruses or bacterial invasions, is well known.
, however, researchers need an unusual pathogen, such as Burkhold's bacteria, to discover that abnormal cell fusion is a new kind of warning sign perceived by the immune system.
these findings increase our understanding of how the immune system resists abnormally fused cells -- whether it's due to infection or cell fusion due to exposure to chemicals. Professor
Gan further explains the importance of understanding our enemies: "Our microbial enemies are often our best teachers.
learning how to treat and control infections is extremely important.
However, understanding the interactionbetween pathogens and hosts is equally important because it allows us to discover whether our immune systems are capable of confrontation, and these basic findings can provide us with a new perspective on staying healthy and treating diseases.
" () References: Joanne Wei Kay Ku et al, Breuer-induced cell fusion is a danger signal signal cGAS-STING via micronuclei formation, proceedings of the National Academy of Sciences (2020).
DOI: 10.1073/pnas.2006908117.