Bacteria may communicate with each other through molecules they produce. The phenomenon is called quorum sensing, and it is important when an infection spreads. Now, it is revealing something more disturbing: how bacteria control processes in human cells by the same mechanism.
When the call is made, more and more bacteria gather at the site of the attack, an injury, for example. When there are enough of them, they begin to act as multicellular organisms. Can form biofilms (also called biofilms) which are capable of resisting dense structures antibiotics attack the body’s immune system.
At the same time become more aggressive and increase their mobility. All these changes are generated when communication molecules (known fatty acids such as AHL) bind to receptors within the bacterial cells and as a result, several genes are activated or deactivated.
These molecules can pass unhindered communication through the cellular membrane, not only in bacterial cells, but also in our own cells, which can promote changes in their functions. At high concentrations, the result may be a weakening of our immune system defenses.
The team of microbiologist Elena Vikstrom, Linkoping University in Sweden, is the first in the world to show how molecules of AHL can affect the body’s cells invaded. Using biochemical methods, researchers have identified a protein, called IQGAP, which they cite as the recipient of the bacteria, and, in a sense, a “double agent”. The protein can both “hear” communications invading bacteria changing the functions in the body’s cells invaded.
Vikstrom team analyzed human epithelial cells of the intestine, which were mixed with the same type of fatty acids produced by Pseudomonas aeruginosa, a bacterium that causes disease resistant in sites such as the lungs, intestines and eyes. With the help of mass spectrometry, researchers have managed to see what proteins bind to the AHL.
Not always required physical contact between bacteria and epithelial cells, the influence distance may occur.
The finding made in this study promises to open the door to new treatment strategies in cases where antibiotics cannot help. One possibility is to design molecules that bind to the receptor and blocking the bacteria the signal path. A strategy that could operate for example against cystic fibrosis, a disease in which patients die from bacterial biofilm infections of the respiratory tract, resistant even more potent antibiotics.